2010 Microchip Technology Inc. Preliminary DS41413A
PIC12F/LF1822/PIC16F/LF1823
Data Sheet
8/14-Pin Flash Microcontrollers
with nanoWatt XLP Technology
DS41413A-page 2 Preliminary 2010 Microchip Technology Inc.
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ISBN: 978-1-60932-051-5
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
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2010 Microchip Technology Inc. Preliminary DS41413A-page 3
High-Performance RISC CPU:
• Only 49 Instructions to Learn:
- All single-cycle instructions except branches
• Operating Speed:
- DC – 32 MHz oscillator/clock input
- DC – 125 ns instruction cycle
• Interrupt Capability with Automatic Context
Saving
• 16-Level Deep Hardware Stack with Optional
Overflow/Underflow Reset
• Direct, Indirect and Relative Addressing modes:
- Two full 16-bit File Select Registers (FSRs)
- FSRs can read program and data memory
Flexible Oscillator Structure:
• Precision 32 MHz internal Oscillator Block:
- Factory calibrated to ± 1%, typical
- Software selectable frequencies range of
31 kHz to 32 MHz
• 31 kHz Low-Power Internal Oscillator
• Four crystal modes up to 32 MHz
• Three external clock modes up to 32 MHz
• 4X Phase Lock Loop (PLL)
• Fail-Safe Clock Monitor:
- Allows for safe shutdown if peripheral clock
stops
• Two-Speed Oscillator Start-up
• Reference Clock Module:
- Programmable clock output frequency and
duty-cycle
Special Microcontroller Features:
• Full 5.5V operation – PIC12F1822/16F1823
• 1.8V-3.6V operation – PIC12LF1822/16LF1823
• Self-reprogrammable under software control
• Power-on Reset (POR), Power-up Timer (PWRT)
and Oscillator Start-up Timer (OST)
• Programmable Brown-out Reset (BOR)
• Extended Watchdog Timer (WDT)
• In-Circuit Serial Programming™ (ICSP™) via
two pins
• In-Circuit Debug (ICD) via two pins
• Enhanced Low-Voltage Programming (LVP)
• Operating Voltage Range:
- 1.8V-5.5V (PIC12F1822/16F1823)
- 1.8V-3.6V (PIC12LF1822/16LF1823)
• Programmable Code Protection
• Self-Programmable under Software Control
Low-Power Features:
• Standby Current (PIC12LF1822/16LF1823):
- 30 nA @ 1.8V, typical
• Operating Current (PIC12LF1822/16LF1823):
-75A @ 1 MHz, 1.8V, typical
• Low-Power Watchdog Timer Current
(PIC12LF1822/16LF1823):
- 500 nA @ 1.8V, typical
Analog Features:
• Analog-to-Digital Converter (ADC) module:
- 10-bit resolution, up to 8 channels
- Conversion available during Sleep
• Analog Comparator module:
- Up to two rail-to-rail analog comparators
- Power mode control
- Software controllable hysteresis
• Voltage Reference module:
- Fixed Voltage Reference (FVR) with 1.024V,
2.048V and 4.096V output levels
- 5-bit rail-to-rail resistive DAC with positive
and negative reference selection
Peripheral Highlights:
• Up to 11 I/O pins and 1 input only pin:
- High current sink/source 25 mA/25 mA
- Programmable weak pull-ups
- Programmable interrupt-on-change pins
• Timer0: 8-Bit Timer/Counter with 8-Bit Prescaler
• Enhanced Timer1:
- 16-bit timer/counter with prescaler
- External Gate Input mode
- Dedicated, low-power 32 kHz oscillator driver
• Timer2: 8-Bit Timer/Counter with 8-Bit Period
Register, Prescaler and Postscaler
• Enhanced CCP (ECCP) modules:
- Software selectable time bases
- Auto-shutdown and auto-restart
- PWM steering
• Master Synchronous Serial Port (MSSP) with SPI
and I2CTM with:
- 7-bit address masking
- SMBus/PMBusTM compatibility
• Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module:
- RS-232, RS-485 and LIN compatible
- Auto-Baud Detect
• mTouch™ Sensing oscillator module:
- Up to 8 input channels
PIC12F/LF1822/16F/LF1823
8/14-Pin Flash Microcontrollers with nanoWatt Technology
PIC12F/LF1822/16F/LF1823
DS41413A-page 4 Preliminary 2010 Microchip Technology Inc.
Peripheral Features (Continued):
• Data Signal Modulator module
- Selectable modulator and carrier sources
•SR Latch:
- Multiple Set/Reset input options
- Emulates 555 Timer applications
PIC12F/LF1822/16F/LF1823 Family Types
Device
Program
Memory
Data
Memory
I/O’s(1)
10-bit ADC (ch)
CapSense (ch)
Comparators
Timers (8/16-bit)
EUSART
MSSP
ECCP (Full-Bridge)
ECCP (Half-Bridge)
SR Latch
Words
SRAM
(bytes)
Data EEPROM
(bytes)
PIC12LF1822 2K 12825664412/111—1Yes
PIC12F1822 2K 128 256 64412/1 1 1 — 1 Yes
PIC16LF1823 2K 128 256 12 8 8 2 2/1 1 1 1 — Yes
PIC16F1823 2K 128 256 12 8822/1 1 1 1 — Ye s
Note 1: One pin is input only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 5
PIC12F/LF1822/16F/LF1823
FIGURE 1: 8-PIN DIAGRAM FOR PIC12F/LF1822
TABLE 1: 8-PIN ALLOCATION TABLE (PIC12F/LF1822)
I/O
8-Pin PDIP/SOIC/DFN
A/D
Reference
Cap Sense
Comparator
SR Latch
Timers
ECCP
EUSART
MSSP
Interrupt
Modulator
Pull-up
Basic
RA0 7AN0 DACOUT CPS0 C1IN+ — — P1B(1) TX(1)
CK(1)
SDO(1)
SS(1)
IOC MDOUT YICSPDAT
ICDDAT
RA1 6AN1 VREF CPS1 C1IN0- SRI — — RX(1)
DT(1)
SCL
SCK
IOC MDMIN Y ICSPCLK
ICPCLK
RA2 5AN2 —CPS2 C1OUT SRQ T0CKI CCP1(1)
P1A(1)
FLT0
—SDA
SDI
INT/
IOC
MDCIN1 Y —
RA3 4—————T1G
(1) ——
SS(1) IOC — Y MCLR
VPP
RA4 3AN3 —CPS3 C1IN1- —T1G(1)
T1OSO
P1B(1) TX(1)
CK(1)
SDO(1) IOC MDCIN2 YOSC2
CLKOUT
CLKR
RA5 2 — — — — SRNQ T1CKI
T1OSI
CCP1(1)
P1A(1)
RX(1)
DT(1)
— IOC — Y OSC1
CLKIN
VDD 1 — — — — — — — — — — — — VDD
VSS 8————————————VSS
Note 1: Pin function is selectable via the APFCON register.
PDIP, SOIC, DFN
1
2
3
4
8
7
6
5
VDD
RX(1)/DT(1)/CCP1(1)/P1A(1)/SRNQ/T1CKI/T1OSI/OSC1/CLKIN/RA5
MDCIN2/T1G(1)/P1B(1)/TX(1)/CK(1)/SDO(1)/CLKR/C1IN1-/T1OSO/CLKOUT/OSC2/CPS3/AN3/RA4
MCLR/VPP/T1G(1)/SS(1)/RA3
VSS
RA0/AN0/CPS0/C1IN+/DACOUT/TX(1)/CK(1)/SDO(1)/SS(1)/P1B(1)/MDOUT/ICSPDAT
RA1/AN1/CPS1/VREF/C1IN0-/SRI/RX(1)/DT(1)/SCL/SCK/MDMIN/ICSPCLK
RA2/AN2/CPS2/C1OUT/SRQ/T0CKI/CCP1(1)/P1A(1)/FLT0/SDA/SDI/INT/MDCIN1
Note 1: Pin function is selectable via the APFCON register.
PIC12F/LF1822/16F/LF1823
DS41413A-page 6 Preliminary 2010 Microchip Technology Inc.
FIGURE 2: 14-PIN DIAGRAM FOR PIC16F/LF1823
PDIP, SOIC, TSSOP
PIC16F/LF1823
1
2
3
4
14
13
12
11
5
6
7
10
9
8
VDD
T1CKI/T1OSI/OSC1/CLKIN/RA5
T1G(1)/SDO(1)/CLKR/T1OSO/CLKOUT/OSC2/CPS3/AN3/RA4
MCLR/VPP/T1G(1)/SS(1)/RA3
MDCIN2/RX(1)/DT(1)/CCP1/P1A/RC5
MDOUT/TX(1)/CK(1)/P1B/SRNQ/C2OUT/RC4
MDMIN/SS(1)/P1C/C12IN3-/CPS7/AN7/RC3
VSS
RA0/AN0/CPS0/C1IN+/DACOUT/TX(1)/CK(1)/ICSPDAT/ICDDAT
RA1/AN1/CPS1/C12IN0-/VREF/SRI/RX(1)/DT(1)/ICSPCLK
RA2/AN2/CPS2/T0CKI/INT/C1OUT/SRQ/FLT0
RC0/AN4/CPS4/C2IN+/SCL/SCK
RC1/AN5/CPS5/C12IN1-/SDA/SDI
RC2/AN6/CPS6/C12IN2-/P1D/SDO(1)/MDCIN1
Note 1: Pin function is selectable via the APFCON register.
2010 Microchip Technology Inc. Preliminary DS41413A-page 7
PIC12F/LF1822/16F/LF1823
FIGURE 3: 14-PIN DIAGRAM FOR PIC16F/LF1823
1
2
3
49
10
11
12
5
6
7
8
16
15
14
13
PIC16F/LF1823
VDD
NC
NC
VSS
T1CKI/T1OSI/OSC1/CLKIN/RA5
T1G(1)/SDO(1)/CLKR/T1OSO/CLKOUT/OSC2/CPS3/AN3/RA4
MCLR/VPP/T1G(1)/SS(1)/RA3
MDCIN2/RX(1)/DT(1)/CCP1/P1A/RC5
RA0/AN0/CPS0/C1IN+/DACOUT/TX(1)/CK(1)/ICSPDAT/ICDDAT
RA1/AN1/CPS1/C12IN0-/VREF/SRI/RX(1)/DT(1)/ICSPCLK
RA2/AN2/CPS2/T0CKI/INT/C1OUT/SRQ/FLT0
RC0/AN4/CPS4/C2IN+/SCL/SCK
MDOUT/TX(1)/CK(1)/P1B/SRNQ/C2OUT/RC4
MDMIN/SS(1)/P1C/C12IN3-/CPS7/AN7/RC3
MDCIN1/SDO(1)/P1D/C12IN2-/CPS6/AN6/RC2
SDI/SDA/C12IN1-/CPS5/AN5/RC1
QFN
Note 1: Pin function is selectable via the APFCON register.
PIC12F/LF1822/16F/LF1823
DS41413A-page 8 Preliminary 2010 Microchip Technology Inc.
TABLE 2: 14-PIN ALLOCATION TABLE (PIC16F/LF1823)
I/O
14-Pin PDIP/SOIC/TSSOP
16-Pin QFN
A/D
Reference
Cap Sense
Comparator
SR Latch
Timers
ECCP
EUSART
MSSP
Interrupt
Modulator
Pull-up
Basic
RA0 13 12 AN0 DACOUT CPS0 C1IN+ — — — TX(1)
CK(1) —IOC — Y ICSPDAT
ICDDAT
RA1 12 11 AN1 VREF CPS1 C12IN0- SRI — — RX(1)
DT(1) — IOC — Y ICSPCLK
ICDCLK
RA2 11 10 AN2 —CPS2 C1OUT SRQ T0CKI FLT0 — — INT/
IOC
— Y —
RA3 4 3 — — — — — T1G(1) ——
SS(1) IOC — Y MCLR
VPP
RA4 3 2 AN3 —CPS3 — — T1G(1)
T1OSO
—SDO(1) IOC — Y OSC2
CLKOUT
CLKR
RA5 2 1 — — — — — T1CKI
T1OSI
—— —IOC—YOSC1
CLKIN
RC0 10 9AN4 —CPS4 C2IN+ — — — — SCL
SCK
— — Y —
RC1 9 8 AN5 — CPS5 C12IN1- — — — — SDA
SDI
——Y—
RC2 8 7 AN6 —CPS6 C12IN2- — — P1D —SDO(1) —MDCIN1 Y —
RC3 7 6 AN7 — CPS7 C12IN3- — — P1C — SS(1) —MDMINY —
RC4 6 5 — — — C2OUT SRNQ —P1B TX(1)
CK(1) — — MDOUT Y —
RC5 5 4 — — — — — — CCP1
P1A
RX(1)
DT(1) — — MDCIN2 Y —
VDD 116 — — — — — — — — — — — — VDD
VSS 1413————————————VSS
Note 1: Pin function is selectable via the APFCON register.
2010 Microchip Technology Inc. Preliminary DS41413A-page 9
PIC12F/LF1822/16F/LF1823
Table of Contents
1.0 Device Overview ........................................................................................................................................................................ 11
2.0 Enhanced Mid-range CPU ......................................................................................................................................................... 19
3.0 Memory Organization ................................................................................................................................................................. 21
4.0 Device Configuration.................................................................................................................................................................. 49
5.0 Oscillator Module (With Fail-Safe Clock Monitor)....................................................................................................................... 55
6.0 Reference Clock Module ............................................................................................................................................................ 71
7.0 Resets ........................................................................................................................................................................................ 75
8.0 Interrupts .................................................................................................................................................................................... 83
9.0 Power-Down Mode (Sleep) ........................................................................................................................................................ 95
10.0 Watchdog Timer (WDT) ............................................................................................................................................................. 99
11.0 Data EEPROM and Flash Program Memory Control ............................................................................................................... 103
12.0 I/O Ports ................................................................................................................................................................................... 117
13.0 Interrupt-on-Change ................................................................................................................................................................. 127
14.0 Fixed Voltage Reference (FVR) ............................................................................................................................................... 131
15.0 Analog-to-Digital Converter (ADC) Module .............................................................................................................................. 133
16.0 Digital-to-Analog Converter (DAC) Module .............................................................................................................................. 147
17.0 SR Latch................................................................................................................................................................................... 153
18.0 Comparator Module.................................................................................................................................................................. 159
19.0 Timer0 Module ......................................................................................................................................................................... 169
20.0 Timer1 Module ......................................................................................................................................................................... 172
21.0 Timer2 Modules........................................................................................................................................................................ 184
22.0 Data Signal Modulator (DSM) .................................................................................................................................................. 189
23.0 Capture/Compare/PWM Module .............................................................................................................................................. 199
24.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 225
25.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 279
26.0 Capacitive Sensing Module...................................................................................................................................................... 307
27.0 In-Circuit Serial Programming™ (ICSP™) ................................................................................................................................ 315
28.0 Instruction Set Summary.......................................................................................................................................................... 319
29.0 Electrical Specifications............................................................................................................................................................ 333
30.0 DC and AC Characteristics Graphs and Tables....................................................................................................................... 365
31.0 Development Support............................................................................................................................................................... 367
32.0 Packaging Information.............................................................................................................................................................. 371
Appendix A: Revision History............................................................................................................................................................. 387
Appendix B: Device Differences ........................................................................................................................................................ 387
Index .................................................................................................................................................................................................. 389
The Microchip Web Site..................................................................................................................................................................... 395
Customer Change Notification Service .............................................................................................................................................. 395
Customer Support .............................................................................................................................................................................. 395
Reader Response .............................................................................................................................................................................. 396
Product Identification System ............................................................................................................................................................ 397
PIC12F/LF1822/16F/LF1823
DS41413A-page 10 Preliminary 2010 Microchip Technology Inc.
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2010 Microchip Technology Inc. Preliminary DS41413A-page 11
PIC12F/LF1822/16F/LF1823
1.0 DEVICE OVERVIEW
The PIC12F/LF1822/16F/LF1823 are described within
this data sheet. They are available in 8/14 pin packages.
Figure 1-1 shows a block diagram of the
PIC12F/LF1822/16F/LF1823 devices. Tables 1-2 and 1-3
show the pinout descriptions.
Reference Table 1-1 for peripherals available per
device.
TABLE 1-1: DEVICE PERIPHERAL
SUMMARY
Peripheral
PIC12F/LF1822
PIC16F/LF1823
ADC ●●
Capacitive Sensing Module (CSM) ●●
Data EEPROM ●●
Digital-to-Analog Converter (DAC) ●●
Digital Signal Modulator (DSM) ●●
EUSART ●●
Fixed Voltage Reference (FVR) ●●
SR Latch ●●
Capture/Compare/PWM Modules
ECCP1 ●●
Comparators
C1 ●●
C2 ●
Master Synchronous Serial Ports
MSSP ●●
Timers
Timer0 ●●
Timer1 ●●
PIC12F/LF1822/16F/LF1823
DS41413A-page 12 Preliminary 2010 Microchip Technology Inc.
FIGURE 1-1: PIC12F/LF1822/16F/LF1823 BLOCK DIAGRAM
PORTA
EUSART
Comparators
MSSP
Timer1Timer0
ECCP1
ADC
10-Bit
PORTC(3)
SR
Latch
Note 1: See applicable chapters for more information on peripherals.
2: See Table 1-1 for peripherals available on specific devices.
3: PIC16F/LF1823 only.
CPU
Program
Flash Memory
EEPROM
RAM
Timing
Generation
INTRC
Oscillator
MCLR
(Figure 2-1)
Modulator CapSense
Clock
CLKR
Reference
DAC
FVR
OSC1/CLKI
OSC2/CLKO
2010 Microchip Technology Inc. Preliminary DS41413A-page 13
PIC12F/LF1822/16F/LF1823
TABLE 1-2: PIC12F/LF1822 PINOUT DESCRIPTION
Name Function Input
Type
Output
Type Description
RA0/AN0/CPS0/C1IN+/
DACOUT/TX(1)/CK(1)/SDO(1)/
SS(1)/P1B(1)/MDOUT/ICSPDAT/
ICDDAT
RA0 TTL CMOS General purpose I/O.
AN0 AN — A/D Channel 0 input.
CPS0 AN — Capacitive sensing input 0.
C1IN+ AN — Comparator C1 positive input.
DACOUT — AN Digital-to-Analog Converter output.
TX — CMOS USART asynchronous transmit.
CK ST CMOS USART synchronous clock.
SDO — CMOS SPI data output.
SS ST — Slave Select input.
P1B — CMOS PWM output.
MDOUT — CMOS Modulator output.
ICSPDAT ST CMOS ICSP™ Data I/O.
RA1/AN1/CPS1/VREF/C1IN0-/
SRI/RX(1)/DT(1)/SCL/SCK/
MDMIN/ICSPCLK/ICDCLK
RA1 TTL CMOS General purpose I/O.
AN1 AN — A/D Channel 1 input.
CPS1 AN — Capacitive sensing input 1.
VREF AN — A/D and DAC Positive Voltage Reference input.
C1IN0- AN — Comparator C1 or C2 negative input.
SRI ST — SR Latch input.
RX ST — USART asynchronous input.
DT ST CMOS USART synchronous data.
SCL I2C™ OD I2C™ clock.
SCK ST CMOS SPI clock.
MDMIN — CMOS Modulator source input.
ICSPCLK ST — Serial Programming Clock.
RA2/AN2/CPS2/C1OUT/SRQ/
T0CKI/CCP1(1)/P1A(1)/FLT0/SD
A/SDI/INT/MDCIN1
RA2 TTL CMOS General purpose I/O.
AN2 AN — A/D Channel 2 input.
CPS2 AN — Capacitive sensing input 2.
C1OUT — CMOS Comparator C1 output.
SRQ — CMOS SR Latch non-inverting output.
T0CKI ST — Timer0 clock input.
CCP1 ST CMOS Capture/Compare/PWM 1.
P1A — CMOS PWM output.
FLT0 ST — ECCP Auto-Shutdown Fault input.
SDA I2C™ OD I2C™ data input/output.
SDI CMOS — SPI data input.
INT ST — External interrupt.
MDCIN1 ST — Modulator Carrier Input 1.
RA3/SS(1)/T1G(1)/VPP/MCLR RA3 TTL — General purpose input.
SS ST — Slave Select input.
T1G ST — Timer1 Gate input.
VPP HV — Programming voltage.
MCLR ST — Master Clear with internal pull-up.
Legend: AN = Analog input or output CMOS= CMOS compatible input or output OD = Open Drain
TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C
HV = High Voltage XTAL = Crystal levels
Note 1: Pin functions can be assigned to one of two pin locations via software. See APFCON register (Register 12-1).
PIC12F/LF1822/16F/LF1823
DS41413A-page 14 Preliminary 2010 Microchip Technology Inc.
RA4/AN3/CPS3/OSC2/
CLKOUT/T1OSO/C1IN1-/CLKR/
SDO(1)/CK(1)/TX(1)/P1B(1)/
T1G(1)/MDCIN2
RA4 TTL CMOS General purpose I/O.
AN3 AN — A/D Channel 3 input.
CPS3 AN — Capacitive sensing input 3.
OSC2 — CMOS Comparator C2 output.
CLKOUT — CMOS FOSC/4 output.
T1OSO XTAL XTAL Timer1 oscillator connection.
C1IN1- AN — Comparator C1 negative input.
CLKR — CMOS Clock Reference output.
SDO — CMOS SPI data output.
CK ST CMOS USART synchronous clock.
TX — CMOS USART asynchronous transmit.
P1B — CMOS PWM output.
T1G ST — Timer1 Gate input.
MDCIN2 ST — Modulator Carrier Input 2.
RA5/CLKIN/OSC1/T1OSI/
T1CKI/SRNQ/P1A(1)/CCP1(1)/
DT(1)/RX(1)
RA5 TTL CMOS General purpose I/O.
CLKIN CMOS — External clock input (EC mode).
OSC1 XTAL — Crystal/Resonator (LP, XT, HS modes).
T1OSI XTAL XTAL Timer1 oscillator connection.
T1CKI ST — Timer1 clock input.
SRNQ — CMOS SR Latch inverting output.
P1A — CMOS PWM output.
CCP1 ST CMOS Capture/Compare/PWM 1.
DT ST CMOS USART synchronous data.
RX ST — USART asynchronous input.
VDD VDD Power — Positive supply.
VSS VSS Power — Ground reference.
TABLE 1-2: PIC12F/LF1822 PINOUT DESCRIPTION (CONTINUED)
Name Function Input
Type
Output
Type Description
Legend: AN = Analog input or output CMOS= CMOS compatible input or output OD = Open Drain
TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C
HV = High Voltage XTAL = Crystal levels
Note 1: Pin functions can be assigned to one of two pin locations via software. See APFCON register (Register 12-1).
2010 Microchip Technology Inc. Preliminary DS41413A-page 15
PIC12F/LF1822/16F/LF1823
TABLE 1-3: PIC16F/LF1823 PINOUT DESCRIPTION
Name Function Input
Type
Output
Type Description
RA0/AN0/CPS0/C1IN+/
DACOUT/TX(1)/CK(1)/ICSPDAT/
ICDDAT
RA0 TTL CMOS General purpose I/O.
AN0 AN — A/D Channel 0 input.
CPS0 AN — Capacitive sensing input 0.
C1IN+ AN — Comparator C1 positive input.
DACOUT — AN Digital-to-Analog Converter output.
TX — CMOS USART asynchronous transmit.
CK ST CMOS USART synchronous clock.
ICSPDAT ST CMOS ICSP™ Data I/O.
RA1/AN1/CPS1/C12IN0-/VREF/
SRI/RX(1)/DT(1)/ICSPCLK/
ICDCLK
RA1 TTL CMOS General purpose I/O.
AN1 AN — A/D Channel 1 input.
CPS1 AN — Capacitive sensing input 1.
C12IN0- AN — Comparator C1 or C2 negative input.
VREF AN — A/D and DAC Positive Voltage Reference input.
SRI ST — SR Latch input.
RX ST — USART asynchronous input.
DT ST CMOS USART synchronous data.
ICSPCLK ST — Serial Programming Clock.
RA2/AN2/CPS2/T0CKI/INT/
C1OUT/SRQ/FLT0
RA2 TTL CMOS General purpose I/O.
AN2 AN — A/D Channel 2 input.
CPS2 AN — Capacitive sensing input 2.
T0CKI ST — Timer0 clock input.
INT ST — External interrupt.
C1OUT — CMOS Comparator C1 output.
SRQ — CMOS SR Latch non-inverting output.
FLT0 ST — ECCP Auto-Shutdown Fault input.
RA3/SS(1)/T1G(1)/VPP/MCLR RA3 TTL — General purpose input.
SS ST — Slave Select input.
T1G ST — Timer1 Gate input.
VPP HV — Programming voltage.
MCLR ST — Master Clear with internal pull-up.
RA4/AN3/CPS3/OSC2/
CLKOUT/T1OSO/CLKR/SDO(1)/
T1G(1)
RA4 TTL CMOS General purpose I/O.
AN3 AN — A/D Channel 3 input.
CPS3 AN — Capacitive sensing input 3.
OSC2 — CMOS Comparator C2 output.
CLKOUT — CMOS FOSC/4 output.
T1OSO XTAL XTAL Timer1 oscillator connection.
CLKR — CMOS Clock Reference output.
SDO — CMOS SPI data output.
T1G ST — Timer1 Gate input.
Legend: AN = Analog input or output CMOS= CMOS compatible input or output OD = Open Drain
TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C
HV = High Voltage XTAL = Crystal levels
Note 1: Pin functions can be assigned to one of two pin locations via software. See APFCON register (Register 12-1).
PIC12F/LF1822/16F/LF1823
DS41413A-page 16 Preliminary 2010 Microchip Technology Inc.
RA5/CLKIN/OSC1/T1OSI/T1CKI RA5 TTL CMOS General purpose I/O.
CLKIN CMOS — External clock input (EC mode).
OSC1 XTAL — Crystal/Resonator (LP, XT, HS modes).
T1OSI XTAL XTAL Timer1 oscillator connection.
T1CKI ST — Timer1 clock input.
RC0/AN4/CPS4/C2IN+/SCL/
SCK
RC0 TTL CMOS General purpose I/O.
AN4 AN — A/D Channel 4 input.
CPS4 AN — Capacitive sensing input 4.
C2IN+ AN — Comparator C2 positive input.
SCL I2C™ OD I2C™ clock.
SCK ST CMOS SPI clock.
RC1/AN5/CPS5/C12IN1-/SDA/
SDI
RC1 TTL CMOS General purpose I/O.
AN5 AN — A/D Channel 5 input.
CPS5 AN — Capacitive sensing input 5.
C12IN1- AN — Comparator C1 or C2 negative input.
SDA I2C™ OD I2C™ data input/output.
SDI CMOS — SPI data input.
RC2/AN6/CPS6/C12IN2-/P1D/
SDO(1)/MDCIN1
RC2 TTL CMOS General purpose I/O.
AN6 AN — A/D Channel 6 input.
CPS6 AN — Capacitive sensing input 6.
C12IN2- AN — Comparator C1 or C2 negative input.
P1D — CMOS PWM output.
SDO — CMOS SPI data output.
MDCIN1 ST — Modulator Carrier Input 1.
RC3/AN7/CPS7/C12IN3-/P1C/
SS(1)/MDMIN
RC6 TTL CMOS General purpose I/O.
AN7 AN — A/D Channel 6 input.
CPS7 AN — Capacitive sensing input 6.
C12IN3- AN — Comparator C1 or C2 negative input.
P1C — CMOS PWM output.
SS ST — Slave Select input.
MDMIN — CMOS Modulator source input.
RC4/C2OUT/SRNQ/P1B/CK(1)/
TX(1)/MDOUT
RC4 TTL CMOS General purpose I/O.
C2OUT — CMOS Comparator C2 output.
SRNQ — CMOS SR Latch inverting output.
P1B — CMOS PWM output.
CK ST CMOS USART synchronous clock.
TX — CMOS USART asynchronous transmit.
MDOUT — CMOS Modulator output.
RC5/P1A/CCP1/DT(1)/RX(1)/
MDCIN2
RC5 TTL CMOS General purpose I/O.
P1A — CMOS PWM output.
CCP1 ST CMOS Capture/Compare/PWM 1.
DT ST CMOS USART synchronous data.
RX ST — USART asynchronous input.
MDCIN2 ST — Modulator Carrier Input 2.
TABLE 1-3: PIC16F/LF1823 PINOUT DESCRIPTION (CONTINUED)
Name Function Input
Type
Output
Type Description
Legend: AN = Analog input or output CMOS= CMOS compatible input or output OD = Open Drain
TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C
HV = High Voltage XTAL = Crystal levels
Note 1: Pin functions can be assigned to one of two pin locations via software. See APFCON register (Register 12-1).
2010 Microchip Technology Inc. Preliminary DS41413A-page 17
PIC12F/LF1822/16F/LF1823
VDD VDD Power — Positive supply.
VSS VSS Power — Ground reference.
TABLE 1-3: PIC16F/LF1823 PINOUT DESCRIPTION (CONTINUED)
Name Function Input
Type
Output
Type Description
Legend: AN = Analog input or output CMOS= CMOS compatible input or output OD = Open Drain
TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C
HV = High Voltage XTAL = Crystal levels
Note 1: Pin functions can be assigned to one of two pin locations via software. See APFCON register (Register 12-1).
PIC12F/LF1822/16F/LF1823
DS41413A-page 18 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 19
PIC12F/LF1822/16F/LF1823
2.0 ENHANCED MID-RANGE CPU
This family of devices contain an enhanced mid-range
8-bit CPU core. The CPU has 49 instructions. Interrupt
capability includes automatic context saving. The
hardware stack is 16 levels deep and has Overflow and
Underflow Reset capability. Direct, Indirect, and
Relative addressing modes are available. Two File
Select Registers (FSRs) provide the ability to read
program and data memory.
• Automatic Interrupt Context Saving
• 16-level Stack with Overflow and Underflow
• File Select Registers
• Instruction Set
2.1 Automatic Interrupt Context
Saving
During interrupts, certain registers are automatically
saved in shadow registers and restored when returning
from the interrupt. This saves stack space and user
code. See Section 8.5 “Automatic Context Saving”,
for more information.
2.2 16-level Stack with Overflow and
Underflow
These devices have an external stack memory 15 bits
wide and 16 words deep. A Stack Overflow or Under-
flow will set the appropriate bit (STKOVF or STKUNF)
in the PCON register, and if enabled will cause a soft-
ware Reset. See section Section 3.4 “Stack” for more
details.
2.3 File Select Registers
There are two 16-bit File Select Registers (FSR). FSRs
can access all file registers and program memory,
which allows one data pointer for all memory. When an
FSR points to program memory, there is 1 additional
instruction cycle in instructions using INDF to allow the
data to be fetched. General purpose memory can now
also be addressed linearly, providing the ability to
access contiguous data larger than 80 bytes. There are
also new instructions to support the FSRs. See
Section 3.5 “Indirect Addressing” for more details.
2.4 Instruction Set
There are 49 instructions for the enhanced mid-range
CPU to support the features of the CPU. See
Section 28.0 “Instruction Set Summary” for more
details.
PIC12F/LF1822/16F/LF1823
DS41413A-page 20 Preliminary 2010 Microchip Technology Inc.
FIGURE 2-1: CORE BLOCK DIAGRAM
Data Bus 8
14
Program
Bus
Instruction reg
Program Counter
8 Level Stack
(13-bit)
Direct Addr 7
12
Addr MUX
FSR reg
STATUS reg
MUX
ALU
Power-up
Timer
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
Instruction
Decode &
Control
Timing
Generation
OSC1/CLKIN
OSC2/CLKOUT
VDD
8
8
Brown-out
Reset
12
3
VSS
Internal
Oscillator
Block
Configuration
Data Bus 8
14
Program
Bus
Instruction reg
Program Counter
8 Level Stack
(13-bit)
Direct Addr 7
Addr MUX
FSR reg
STATUS reg
MUX
ALU
W Reg
Instruction
Decode &
Control
Timing
Generation
VDD
8
8
3
VSS
Internal
Oscillator
Block
Configuration
15 Data Bus 8
14
Program
Bus
Instruction Reg
Program Counter
16-Level Stack
(15-bit)
Direct Addr 7
RAM Addr
Addr MUX
Indirect
Addr
FSR0 Reg
STATUS Reg
MUX
ALU
Instruction
Decode and
Control
Timing
Generation
VDD
8
8
3
VSS
Internal
Oscillator
Block
Configuration
Flash
Program
Memory RAM
FSR regFSR reg
FSR1 Reg
15
15
MUX
15
Program Memory
Read (PMR)
12
FSR regFSR reg
BSR Reg
5
2010 Microchip Technology Inc. Preliminary DS41413A-page 21
PIC12F/LF1822/16F/LF1823
3.0 MEMORY ORGANIZATION
There are three types of memory in
PIC12F/LF1822/16F/LF1823 devices: Data Memory,
Program Memory and Data EEPROM Memory(1).
• Program Memory
• Data Memory
- Core Registers
- Special Function Registers
- General Purpose RAM
- Common RAM
- Device Memory Maps
- Special Function Registers Summary
• Data EEPROM memory(1)
The following features are associated with access and
control of program memory and data memory:
• PCL and PCLATH
•Stack
• Indirect Addressing
3.1 Program Memory Organization
The enhanced mid-range core has a 15-bit program
counter capable of addressing a 32K x 14 program
memory space. Table 3-1 shows the memory sizes
implemented for the PIC12F/LF1822/16F/LF1823
family. Accessing a location above these boundaries will
cause a wrap-around within the implemented memory
space. The Reset vector is at 0000h and the interrupt
vector is at 0004h (see Figures 3-1 and ).
Note 1: The Data EEPROM Memory and the
method to access Flash memory through
the EECON registers is described in
Section 11.0 “Data EEPROM and Flash
Program Memory Control”.
TABLE 3-1: DEVICE SIZES AND ADDRESSES
Device Program Memory Space (Words) Last Program Memory Address
PIC12F/LF1822/16F/LF1823 2,048 07FFh
PIC12F/LF1822/16F/LF1823
DS41413A-page 22 Preliminary 2010 Microchip Technology Inc.
FIGURE 3-1: PROGRAM MEMORY MAP
AND STACK FOR
PIC12F/LF1822/16F/LF1823
3.1.1 READING PROGRAM MEMORY AS
DATA
There are two methods of accessing constants in pro-
gram memory. The first method is to use tables of
RETLW instructions. The second method is to set an
FSR to point to the program memory.
3.1.1.1 RETLW Instruction
The RETLW instruction can be used to provide access
to tables of constants. The recommended way to create
such a table is shown in Example 3-1.
EXAMPLE 3-1: RETLW INSTRUCTION
The BRW instruction makes this type of table very sim-
ple to implement. If your code must remain portable
with previous generations of microcontrollers, then the
BRW instruction is not available so the older table read
method must be used.
PC<14:0>
15
0000h
0004h
Stack Level 0
Stack Level 15
Reset Vector
Interrupt Vector
Stack Level 1
0005h
On-chip
Program
Memory Page 0
07FFh
Wraps to Page 0
Wraps to Page 0
Wraps to Page 0
0800h
CALL, CALLW
RETURN, RETLW
Interrupt, RETFIE
Rollover to Page 0
Rollover to Page 0 7FFFh
constants
brw ;Add Index in W to
;program counter to
;select data
retlw DATA0 ;Index0 data
retlw DATA1 ;Index1 data
retlw DATA2
retlw DATA3
my_function
;… LOTS OF CODE…
movlw DATA_INDEX
call constants
;… THE CONSTANT IS IN W
2010 Microchip Technology Inc. Preliminary DS41413A-page 23
PIC12F/LF1822/16F/LF1823
3.1.1.2 Indirect Read with FSR
The program memory can be accessed as data by set-
ting bit 7 of the FSRxH register and reading the match-
ing INDFx register. The MOVIW instruction will place the
lower 8 bits of the addressed word in the W register.
Writes to the program memory cannot be performed via
the INDF registers. Instructions that access the pro-
gram memory via the FSR require one extra instruction
cycle to complete. Example 3-2 demonstrates access-
ing the program memory via an FSR.
The HIGH directive will set bit<7> if a label points to a
location in program memory.
EXAMPLE 3-2: ACCESSING PROGRAM
MEMORY VIA FSR
3.2 Data Memory Organization
The data memory is partitioned in 32 memory banks
with 128 bytes in a bank. Each bank consists of
(Figure 3-2):
• 12 core registers
• 20 Special Function Registers (SFR)
• Up to 80 bytes of General Purpose RAM (GPR)
• 16 bytes of common RAM
The active bank is selected by writing the bank number
into the Bank Select Register (BSR). Unimplemented
memory will read as ‘0’. All data memory can be
accessed either directly (via instructions that use the
file registers) or indirectly via the two File Select
Registers (FSR). See Section 3.5 “Indirect
Addressing” for more information.
3.2.1 CORE REGISTERS
The core registers contain the registers that directly
affect the basic operation of the
PIC12F/LF1822/16F/LF1823. These registers are
listed below:
• INDF0
• INDF1
•PCL
•STATUS
•FSR0 Low
• FSR0 High
•FSR1 Low
• FSR1 High
• BSR
•WREG
•PCLATH
• INTCON
constants
RETLW DATA0 ;Index0 data
RETLW DATA1 ;Index1 data
RETLW DATA2
RETLW DATA3
my_function
;… LOTS OF CODE…
MOVLW LOW constants
MOVWF FSR1L
MOVLW HIGH constants
MOVWF FSR1H
MOVIW 0[FSR1]
;THE PROGRAM MEMORY IS IN W
Note: The core registers are the first 12
addresses of every data memory bank.
PIC12F/LF1822/16F/LF1823
DS41413A-page 24 Preliminary 2010 Microchip Technology Inc.
3.2.1.1 STATUS Register
The STATUS register, shown in Register 3-1, contains:
• the arithmetic status of the ALU
• the Reset status
The STATUS register can be the destination for any
instruction, like any other register. If the STATUS
register is the destination for an instruction that affects
the Z, DC or C bits, then the write to these three bits is
disabled. These bits are set or cleared according to the
device logic. Furthermore, the TO and PD bits are not
writable. Therefore, the result of an instruction with the
STATUS register as destination may be different than
intended.
For example, CLRF STATUS will clear the upper three
bits and set the Z bit. This leaves the STATUS register
as ‘000u u1uu’ (where u = unchanged).
It is recommended, therefore, that only BCF, BSF,
SWAPF and MOVWF instructions are used to alter the
STATUS register, because these instructions do not
affect any Status bits. For other instructions not
affecting any Status bits (Refer to Section 28.0
“Instruction Set Summary”).
Note 1: The C and DC bits operate as Borrow and
Digit Borrow out bits, respectively, in
subtraction.
REGISTER 3-1: STATUS: STATUS REGISTER
U-0 U-0 U-0 R-1/q R-1/q R/W-0/u R/W-0/u R/W-0/u
— — — TO PD ZDC
(1) C(1)
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition
bit 7-5 Unimplemented: Read as ‘0’
bit 4 TO: Time-out bit
1 = After power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
bit 3 PD: Power-down bit
1 = After power-up or by the CLRWDT instruction
0 = By execution of the SLEEP instruction
bit 2 Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1 DC: Digit Carry/Digit Borrow bit(1)
1 = A carry-out from the 4th low-order bit of the result occurred
0 = No carry-out from the 4th low-order bit of the result
bit 0 C: Carry/Borrow bit(1)
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Note 1: For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand.
2010 Microchip Technology Inc. Preliminary DS41413A-page 25
PIC12F/LF1822/16F/LF1823
3.2.2 SPECIAL FUNCTION REGISTER
The Special Function Registers are registers used by
the application to control the desired operation of
peripheral functions in the device. The registers asso-
ciated with the operation of the peripherals are
described in the appropriate peripheral chapter of this
data sheet.
3.2.3 GENERAL PURPOSE RAM
There are up to 80 bytes of GPR in each data memory
bank.
3.2.3.1 Linear Access to GPR
The general purpose RAM can be accessed in a
non-banked method via the FSRs. This can simplify
access to large memory structures. See Section 3.5.2
“Linear Data Memory” for more information.
3.2.4 COMMON RAM
There are 16 bytes of common RAM accessible from all
banks.
FIGURE 3-2: BANKED MEMORY
PARTITIONING
3.2.5 DEVICE MEMORY MAPS
The memory maps for the device family are as shown
in Table 3-2.
0Bh
0Ch
1Fh
20h
6Fh
70h
7Fh
00h
Common RAM
(16 bytes)
General Purpose RAM
(80 bytes maximum)
Core Registers
(12 bytes)
Special Function Registers
(20 bytes maximum)
Memory Region
7-bit Bank Offset
TABLE 3-2: MEMORY MAP TABLES
Device Banks Table No.
PIC12F/LF1822/16F/LF1823 0-7 Table 3-3
8-15 Table 3-4
16-23 Table 3-5
24-31 Table 3-6
31 Table 3-7
PIC12F/LF1822/16F/LF1823
DS41413A-page 26 Preliminary 2010 Microchip Technology Inc.
TABLE 3-3: PIC12F/LF1822/PIC16F/LF1823 MEMORY MAP, BANKS 0-7
Legend: = Unimplemented data memory locations, read as ‘0’
Note 1: Available only on PIC16F/LF1823.
BANK0 BANK1 BANK2 BANK3 BANK4 BANK5 BANK6 BANK7
000h INDF0 080h INDF0 100h INDF0 180h INDF0 200h INDF0 280h INDF0 300h INDF0 380h INDF0
001h INDF1 081h INDF1 101h INDF1 181h INDF1 201h INDF1 281h INDF1 301h INDF1 381h INDF1
002h PCL 082h PCL 102h PCL 182h PCL 202h PCL 282h PCL 302h PCL 382h PCL
003h STATUS 083h STATUS 103h STATUS 183h STATUS 203h STATUS 283h STATUS 303h STATUS 383h STATUS
004h FSR0L 084h FSR0L 104h FSR0L 184h FSR0L 204h FSR0L 284h FSR0L 304h FSR0L 384h FSR0L
005h FSR0H 085h FSR0H 105h FSR0H 185h FSR0H 205h FSR0H 285h FSR0H 305h FSR0H 385h FSR0H
006h FSR1L 086h FSR1L 106h FSR1L 186h FSR1L 206h FSR1L 286h FSR1L 306h FSR1L 386h FSR1L
007h FSR1H 087h FSR1H 107h FSR1H 187h FSR1H 207h FSR1H 287h FSR1H 307h FSR1H 387h FSR1H
008h BSR 088h BSR 108h BSR 188h BSR 208h BSR 288h BSR 308h BSR 388h BSR
009h WREG 089h WREG 109h WREG 189h WREG 209h WREG 289h WREG 309h WREG 389h WREG
00Ah PCLATH 08Ah PCLATH 10Ah PCLATH 18Ah PCLATH 20Ah PCLATH 28Ah PCLATH 30Ah PCLATH 38Ah PCLATH
00Bh INTCON 08Bh INTCON 10Bh INTCON 18Bh INTCON 20Bh INTCON 28Bh INTCON 30Bh INTCON 38Bh INTCON
00Ch PORTA 08Ch TRISA 10Ch LATA 18Ch ANSELA 20Ch WPUA 28Ch — 30Ch — 38Ch —
00Dh — 08Dh — 10Dh — 18Dh — 20Dh — 28Dh — 30Dh — 38Dh —
00Eh PORTC(1) 08Eh TRISC(1) 10Eh LATC(1) 18Eh ANSELC(1) 20Eh WPUC(1) 28Eh —30Eh—38Eh—
00Fh —08Fh—10Fh—18Fh—20Fh—28Fh—30Fh—38Fh—
010h —090h—110h—190h—210h—290h— 310h — 390h —
011h PIR1 091h PIE1 111h CM1CON0 191h EEADRL 211h SSPBUF 291h CCPR1L 311h — 391h IOCAP
012h PIR2 092h PIE2 112h CM1CON1 192h EEADRH 212h SSPADD 292h CCPR1H 312h — 392h IOCAN
013h —093h— 113h CM2CON0 193h EEDATL 213h SSPMASK 293h CCP1CON 313h — 393h IOCAF
014h —094h— 114h CM2CON1 194h EEDATH 214h SSPSTAT 294h PWM1CON 314h — 394h —
015h TMR0 095h OPTION 115h CMOUT 195h EECON1 215h SSPCON 295h CCP1AS 315h — 395h —
016h TMR1L 096h PCON 116h BORCON 196h EECON2 216h SSPCON2 296h PSTR1CON 316h — 396h —
017h TMR1H 097h WDTCON 117h FVRCON 197h — 217h SSPCON3 297h — 317h — 397h —
018h T1CON 098h OSCTUNE 118h DACCON0 198h —218h—298h—318h —398h —
019h T1GCON 099h OSCCON 119h DACCON1 199h RCREG 219h —299h —319h —399h —
01Ah TMR2 09Ah OSCSTAT 11Ah SRCON0 19Ah TXREG 21Ah —29Ah —31Ah —39Ah CLKRCON
01Bh PR2 09Bh ADRESL 11Bh SRCON1 19Bh SPBRGL 21Bh —29Bh —31Bh —39Bh—
01Ch T2CON 09Ch ADRESH 11Ch — 19Ch SPBRGH 21Ch —29Ch —31Ch — 39Ch MDCON
01Dh — 09Dh ADCON0 11Dh APFCON 19Dh RCSTA 21Dh — 29Dh — 31Dh —39Dh MDSRC
01Eh CPSCON0 09Eh ADCON1 11Eh —19Eh TXSTA 21Eh —29Eh—31Eh—39Eh MDCARL
01Fh CPSCON1 09Fh —11Fh— 19Fh BAUDCON 21Fh —29Fh—31Fh—39Fh
MDCARH
020h
General
Purpose
Register
96 Bytes
0A0h General
Purpose
Register
32 Bytes
120h
Unimplemented
Read as ‘0’
1A0h
Unimplemented
Read as ‘0’
220h
Unimplemented
Read as ‘0’
2A0h
Unimplemented
Read as ‘0’
320h
Unimplemented
Read as ‘0’
3A0h
Unimplemented
Read as ‘0’
0BFh
Unimplemented
Read as ‘0’
06Fh 0EFh 16Fh 1EFh 26Fh 2EFh 36Fh 3EFh
070h 0F0h
Accesses
70h – 7Fh
170h
Accesses
70h – 7Fh
1F0h
Accesses
70h – 7Fh
270h
Accesses
70h – 7Fh
2F0h
Accesses
70h – 7Fh
370h
Accesses
70h – 7Fh
3F0h
Accesses
70h – 7Fh
07Fh 0FFh 17Fh 1FFh 27Fh 2FFh 37Fh 3FFh
2010 Microchip Technology Inc. Preliminary DS41413A-page 27
PIC12F/LF1822/16F/LF1823
TABLE 3-4: PIC12F/LF1822/16F/LF1823 MEMORY MAP, BANKS 8-15
Legend: = Unimplemented data memory locations, read as ‘0’
BANK 8 BANK 9 BANK 10 BANK 11 BANK 12 BANK 13 BANK 14 BANK 15
400h INDF0 480h INDF0 500h INDF0 580h INDF0 600h INDF0 680h INDF0 700h INDF0 780h INDF0
401h INDF1 481h INDF1 501h INDF1 581h INDF1 601h INDF1 681h INDF1 701h INDF1 781h INDF1
402h PCL 482h PCL 502h PCL 582h PCL 602h PCL 682h PCL 702h PCL 782h PCL
403h STATUS 483h STATUS 503h STATUS 583h STATUS 603h STATUS 683h STATUS 703h STATUS 783h STATUS
404h FSR0L 484h FSR0L 504h FSR0L 584h FSR0L 604h FSR0L 684h FSR0L 704h FSR0L 784h FSR0L
405h FSR0H 485h FSR0H 505h FSR0H 585h FSR0H 605h FSR0H 685h FSR0H 705h FSR0H 785h FSR0H
406h FSR1L 486h FSR1L 506h FSR1L 586h FSR1L 606h FSR1L 686h FSR1L 706h FSR1L 786h FSR1L
407h FSR1H 487h FSR1H 507h FSR1H 587h FSR1H 607h FSR1H 687h FSR1H 707h FSR1H 787h FSR1H
408h BSR 488h BSR 508h BSR 588h BSR 608h BSR 688h BSR 708h BSR 788h BSR
409h WREG 489h WREG 509h WREG 589h WREG 609h WREG 689h WREG 709h WREG 789h WREG
40Ah PCLATH 48Ah PCLATH 50Ah PCLATH 58Ah PCLATH 60Ah PCLATH 68Ah PCLATH 70Ah PCLATH 78Ah PCLATH
40Bh INTCON 48Bh INTCON 50Bh INTCON 58Bh INTCON 60Bh INTCON 68Bh INTCON 70Bh INTCON 78Bh INTCON
40Ch —48Ch —50Ch —58Ch —60Ch —68Ch —70Ch —78Ch —
40Dh —48Dh —50Dh —58Dh —60Dh —68Dh —70Dh —78Dh —
40Eh —48Eh —50Eh —58Eh —60Eh —68Eh —70Eh —78Eh —
40Fh —48Fh —50Fh —58Fh —60Fh —68Fh —70Fh —78Fh —
410h —490h —510h —590h —610h —690h —710h —790h —
411h —491h —511h —591h —611h —691h —711h —791h —
412h —492h —512h —592h —612h —692h —712h —792h —
413h —493h —513h —593h —613h —693h —713h —793h —
414h —494h —514h —594h —614h —694h —714h —794h —
415h —495h —515h —595h —615h —695h —715h —795h —
416h —496h —516h —596h —616h —696h —716h —796h —
417h —497h —517h —597h —617h —697h —717h —797h —
418h —498h —518h —598h —618h —698h —718h —798h —
419h —499h —519h —599h —619h —699h —719h —799h —
41Ah —49Ah —51Ah —59Ah —61Ah —69Ah —71Ah —79Ah —
41Bh —49Bh —51Bh —59Bh —61Bh —69Bh —71Bh —79Bh —
41Ch —49Ch —51Ch —59Ch —61Ch —69Ch —71Ch —79Ch —
41Dh —49Dh —51Dh —59Dh —61Dh —69Dh —71Dh —79Dh —
41Eh —49Eh —51Eh —59Eh —61Eh —69Eh —71Eh —79Eh —
41Fh —49Fh —51Fh —59Fh —61Fh —69Fh —71Fh —79Fh —
420h
Unimplemented
Read as ‘0’
4A0h
Unimplemented
Read as ‘0’
520h
Unimplemented
Read as ‘0’
5A0h
Unimplemented
Read as ‘0’
620h
Unimplemented
Read as ‘0’
6A0h
Unimplemented
Read as ‘0’
720h
Unimplemented
Read as ‘0’
7A0h
Unimplemented
Read as ‘0’
46Fh 4EFh 56Fh 5EFh 66Fh 6EFh 76Fh 7EFh
470h
Accesses
70h – 7Fh
4F0h
Accesses
70h – 7Fh
570h
Accesses
70h – 7Fh
5F0h
Accesses
70h – 7Fh
670h
Accesses
70h – 7Fh
6F0h
Accesses
70h – 7Fh
770h
Accesses
70h – 7Fh
7F0h
Accesses
70h – 7Fh
47Fh 4FFh 57Fh 5FFh 67Fh 6FFh 77Fh 7FFh
PIC12F/LF1822/16F/LF1823
DS41413A-page 28 Preliminary 2010 Microchip Technology Inc.
TABLE 3-5: PIC12F/LF1822/16F/LF1823 MEMORY MAP, BANKS 16-23
Legend: = Unimplemented data memory locations, read as ‘0’
BANK16 BANK17 BANK18 BANK19 BANK20 BANK21 BANK22 BANK23
800h INDF0 880h INDF0 900h INDF0 980h INDF0 A00h INDF0 A80h INDF0 B00h INDF0 B80h INDF0
801h INDF1 881h INDF1 901h INDF1 981h INDF1 A01h INDF1 A81h INDF1 B01h INDF1 B81h INDF1
802h PCL 882h PCL 902h PCL 982h PCL A02h PCL A82h PCL B02h PCL B82h PCL
803h STATUS 883h STATUS 903h STATUS 983h STATUS A03h STATUS A83h STATUS B03h STATUS B83h STATUS
804h FSR0L 884h FSR0L 904h FSR0L 984h FSR0L A04h FSR0L A84h FSR0L B04h FSR0L B84h FSR0L
805h FSR0H 885h FSR0H 905h FSR0H 985h FSR0H A05h FSR0H A85h FSR0H B05h FSR0H B85h FSR0H
806h FSR1L 886h FSR1L 906h FSR1L 986h FSR1L A06h FSR1L A86h FSR1L B06h FSR1L B86h FSR1L
807h FSR1H 887h FSR1H 907h FSR1H 987h FSR1H A07h FSR1H A87h FSR1H B07h FSR1H B87h FSR1H
808h BSR 888h BSR 908h BSR 988h BSR A08h BSR A88h BSR B08h BSR B88h BSR
809h WREG 889h WREG 909h WREG 989h WREG A09h WREG A89h WREG B09h WREG B89h WREG
80Ah PCLATH 88Ah PCLATH 90Ah PCLATH 98Ah PCLATH A0Ah PCLATH A8Ah PCLATH B0Ah PCLATH B8Ah PCLATH
80Bh INTCON 88Bh INTCON 90Bh INTCON 98Bh INTCON A0Bh INTCON A8Bh INTCON B0Bh INTCON B8Bh INTCON
80Ch — 88Ch — 90Ch — 98Ch —A0Ch—A8Ch—B0Ch—B8Ch—
80Dh — 88Dh — 90Dh — 98Dh —A0Dh—A8Dh—B0Dh—B8Dh—
80Eh —88Eh—90Eh—98Eh—A0Eh—A8Eh—B0Eh—B8Eh—
80Fh —88Fh—90Fh—98Fh—A0Fh—A8Fh—B0Fh—B8Fh—
810h —890h—910h—990h—A10h—A90h—B10h—B90h—
811h —891h—911h—991h—A11h—A91h—B11h—B91h—
812h —892h—912h—992h—A12h—A92h—B12h—B92h—
813h —893h—913h—993h—A13h—A93h—B13h—B93h—
814h —894h—914h—994h—A14h—A94h—B14h—B94h—
815h —895h—915h—995h—A15h—A95h—B15h—B95h—
816h —896h—916h—996h—A16h—A96h—B16h—B96h—
817h —897h—917h—997h—A17h—A97h—B17h—B97h—
818h —898h—918h—998h—A18h—A98h—B18h—B98h—
819h —899h—919h—999h—A19h—A99h—B19h—B99h—
81Ah —89Ah—91Ah—99Ah—A1Ah—A9Ah—B1Ah—B9Ah—
81Bh —89Bh—91Bh—99Bh—A1Bh—A9Bh—B1Bh—B9Bh—
81Ch — 89Ch — 91Ch — 99Ch —A1Ch—A9Ch—B1Ch—B9Ch—
81Dh — 89Dh — 91Dh — 99Dh —A1Dh—A9Dh—B1Dh—B9Dh—
81Eh —89Eh—91Eh—99Eh—A1Eh—A9Eh—B1Eh—B9Eh—
81Fh —89Fh—91Fh—99Fh—A1Fh—A9Fh—B1Fh—B9Fh—
820h
Unimplemented
Read as ‘0’
8A0h
Unimplemented
Read as ‘0’
920h
Unimplemented
Read as ‘0’
9A0h
Unimplemented
Read as ‘0’
A20h
Unimplemented
Read as ‘0’
AA0h
Unimplemented
Read as ‘0’
B20h
Unimplemented
Read as ‘0’
BA0h
Unimplemented
Read as ‘0’
86Fh 8EFh 96Fh 9EFh A6Fh AEFh B6Fh BEFh
870h
Accesses
70h – 7Fh
8F0h
Accesses
70h – 7Fh
970h
Accesses
70h – 7Fh
9F0h
Accesses
70h – 7Fh
A70h
Accesses
70h – 7Fh
AF0h
Accesses
70h – 7Fh
B70h
Accesses
70h – 7Fh
BF0h
Accesses
70h – 7Fh
87Fh 8FFh 97Fh 9FFh A7Fh AFFh B7Fh BFFh
2010 Microchip Technology Inc. Preliminary DS41413A-page 29
PIC12F/LF1822/16F/LF1823
TABLE 3-6: PIC12F/LF1822/16F/LF1823 MEMORY MAP, BANKS 24-31
Legend: = Unimplemented data memory locations, read as ‘0’
BANK 24 BANK 25 BANK 26 BANK 27 BANK 28 BANK 29 BANK 30 BANK 31
C00h INDF0 C80h INDF0 D00h INDF0 D80h INDF0 E00h INDF0 E80h INDF0 F00h INDF0 F80h INDF0
C01h INDF1 C81h INDF1 D01h INDF1 D81h INDF1 E01h INDF1 E81h INDF1 F01h INDF1 F81h INDF1
C02h PCL C82h PCL D02h PCL D82h PCL E02h PCL E82h PCL F02h PCL F82h PCL
C03h STATUS C83h STATUS D03h STATUS D83h STATUS E03h STATUS E83h STATUS F03h STATUS F83h STATUS
C04h FSR0L C84h FSR0L D04h FSR0L D84h FSR0L E04h FSR0L E84h FSR0L F04h FSR0L F84h FSR0L
C05h FSR0H C85h FSR0H D05h FSR0H D85h FSR0H E05h FSR0H E85h FSR0H F05h FSR0H F85h FSR0H
C06h FSR1L C86h FSR1L D06h FSR1L D86h FSR1L E06h FSR1L E86h FSR1L F06h FSR1L F86h FSR1L
C07h FSR1H C87h FSR1H D07h FSR1H D87h FSR1H E07h FSR1H E87h FSR1H F07h FSR1H F87h FSR1H
C08h BSR C88h BSR D08h BSR D88h BSR E08h BSR E88h BSR F08h BSR F88h BSR
C09h WREG C89h WREG D09h WREG D89h WREG E09h WREG E89h WREG F09h WREG F89h WREG
C0Ah PCLATH C8Ah PCLATH D0Ah PCLATH D8Ah PCLATH E0Ah PCLATH E8Ah PCLATH F0Ah PCLATH F8Ah PCLATH
C0Bh INTCON C8Bh INTCON D0Bh INTCON D8Bh INTCON E0Bh INTCON E8Bh INTCON F0Bh INTCON F8Bh INTCON
C0Ch —C8Ch—D0Ch—D8Ch—E0Ch—E8Ch—F0Ch—F8Ch
See Table 3-7 for
register mapping
details
C0Dh —C8Dh—D0Dh—D8Dh—E0Dh—E8Dh—F0Dh—F8Dh
C0Eh —C8Eh—D0Eh—D8Eh—E0Eh—E8Eh—F0Eh—F8Eh
C0Fh —C8Fh—D0Fh—D8Fh—E0Fh—E8Fh—F0Fh—F8Fh
C10h —C90h—D10h—D90h—E10h—E90h—F10h—F90h
C11h —C91h—D11h—D91h—E11h—E91h—F11h—F91h
C12h —C92h—D12h—D92h—E12h—E92h—F12h—F92h
C13h —C93h—D13h—D93h—E13h—E93h—F13h—F93h
C14h —C94h—D14h—D94h—E14h—E94h—F14h—F94h
C15h —C95h—D15h—D95h—E15h—E95h—F15h—F95h
C16h —C96h—D16h—D96h—E16h—E96h—F16h—F96h
C17h —C97h—D17h—D97h—E17h—E97h—F17h—F97h
C18h —C98h—D18h—D98h—E18h—E98h—F18h—F98h
C19h —C99h—D19h—D99h—E19h—E99h—F19h—F99h
C1Ah —C9Ah—D1Ah—D9Ah—E1Ah—E9Ah—F1Ah—F9Ah
C1Bh —C9Bh—D1Bh—D9Bh—E1Bh—E9Bh—F1Bh—F9Bh
C1Ch —C9Ch—D1Ch—D9Ch—E1Ch—E9Ch—F1Ch—F9Ch
C1Dh —C9Dh—D1Dh—D9Dh—E1Dh—E9Dh—F1Dh—F9Dh
C1Eh —C9Eh—D1Eh—D9Eh—E1Eh—E9Eh—F1Eh—F9Eh
C1Fh —C9Fh—D1Fh—D9Fh—E1Fh—E9Fh—F1Fh—F9Fh
C20h
Unimplemented
Read as ‘0’
CA0h
Unimplemented
Read as ‘0’
D20h
Unimplemented
Read as ‘0’
DA0h
Unimplemented
Read as ‘0’
E20h
Unimplemented
Read as ‘0’
EA0h
Unimplemented
Read as ‘0’
F20h
Unimplemented
Read as ‘0’
FA0h
C6Fh CEFh D6Fh DEFh E6Fh EEFh F6Fh FEFh
C70h
Accesses
70h – 7Fh
CF0h
Accesses
70h – 7Fh
D70h
Accesses
70h – 7Fh
DF0h
Accesses
70h – 7Fh
E70h
Accesses
70h – 7Fh
EF0h
Accesses
70h – 7Fh
F70h
Accesses
70h – 7Fh
FF0h
Accesses
70h – 7Fh
CFFh CFFh D7Fh DFFh E7Fh EFFh F7Fh FFFh
PIC12F/LF1822/16F/LF1823
DS41413A-page 30 Preliminary 2010 Microchip Technology Inc.
TABLE 3-7: PIC12F/LF1822/16F/LF1823
MEMORY MAP, BANK 31
3.2.6 SPECIAL FUNCTION REGISTERS
SUMMARY
The Special Function Register Summary for the device
family are as follows:
Legend: = Unimplemented data memory locations,
read as ‘0’.
Bank 31
FA0h
FE3h
Unimplemented
Read as ‘0’
FE4h STATUS_SHAD
FE5h WREG_SHAD
FE6h BSR_SHAD
FE7h PCLATH_SHAD
FE8h FSR0L_SHAD
FE9h FSR0H_SHAD
FEAh FSR1L_SHAD
FEBh FSR1H_SHAD
FECh —
FEDh STKPTR
FEEh TOSL
FEFh TOSH
Device Bank(s) Page No.
PIC12F/LF1822/16F/LF1823
031
132
233
334
435
536
637
738
839
9-30 40
31 41
2010 Microchip Technology Inc. Preliminary DS41413A-page 31
PIC12F/LF1822/16F/LF1823
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Bank 0
000h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
001h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
002h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
003h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
004h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
005h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
006h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
007h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
008h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
009h(1) WREG Working Register 0000 0000 uuuu uuuu
00Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
00Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
00Ch PORTA —— RA5 RA4 RA3 RA2 RA1 RA0 --xx xxxx --xx xxxx
00Dh —Unimplemented — —
00Eh PORTC(2) —— RC5 RC4 RC3 RC2 RC1 RC0 --xx xxxx --xx xxxx
00Fh —Unimplemented — —
010h —Unimplemented — —
011h PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 0000 0000 0000 0000
012h PIR2 OSFIF C2IF(2) C1IF EEIF BCL1IF — — — 0000 0--- 0000 0---
013h —Unimplemented — —
014h —Unimplemented — —
015h TMR0 Timer0 Module Register xxxx xxxx uuuu uuuu
016h TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu
017h TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu
018h T1CON TMR1CS1 TMR1CS0 T1CKPS<1:0> T1OSCEN T1SYNC —TMR1ON0000 00-0 uuuu uu-u
019h T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/
DONE
T1GVAL T1GSS<1:0> 0000 0x00 uuuu uxuu
01Ah TMR2 Timer2 Module Register 0000 0000 0000 0000
01Bh PR2 Timer2 Period Register 1111 1111 1111 1111
01Ch T2CON — T2OUTPS<3:0> TMR2ON T2CKPS<1:0> -000 0000 -000 0000
01Dh —Unimplemented — —
01Eh CPSCON0 CPSON CPSRM —— CPSRNG<1:0> CPSOUT T0XCS 00-- 0000 00-- 0000
01Fh CPSCON1 — — — — CPSCH<3:2>(2) CPSCH<1:0> ---- 0000 ---- 0000
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 32 Preliminary 2010 Microchip Technology Inc.
Bank 1
080h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
081h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
082h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
083h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
084h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
085h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
086h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
087h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
088h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
089h(1) WREG Working Register 0000 0000 uuuu uuuu
08Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
08Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
08Ch TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 --11 1111 --11 1111
08Dh —Unimplemented — —
08Eh TRISC(2) —— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 --11 1111 --11 1111
08Fh —Unimplemented — —
090h —Unimplemented — —
091h PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 0000 0000 0000 0000
092h PIE2 OSFIE C2IE(2) C1IE EEIE BCL1IE — — — 0000 0--- 0000 0---
093h —Unimplemented — —
094h —Unimplemented — —
095h
OPTION_REG
WPUEN INTEDG TMR0CS TMR0SE PSA PS<2:0> 1111 1111 1111 1111
096h PCON STKOVF STKUNF ——RMCLRRI POR BOR 00-- 11qq qq-- qquu
097h WDTCON —— WDTPS<4:0> SWDTEN --01 0110 --01 0110
098h OSCTUNE —— TUN<5:0> --00 0000 --00 0000
099h OSCCON SPLLEN IRCF<3:0> —SCS<1:0>0011 1-00 0011 1-00
09Ah OSCSTAT T1OSCR PLLR OSTS HFIOFR HFIOFL MFIOFR LFIOFR HFIOFS 10q0 0q00 qqqq qq0q
09Bh ADRESL A/D Result Register Low xxxx xxxx uuuu uuuu
09Ch ADRESH A/D Result Register High xxxx xxxx uuuu uuuu
09Dh ADCON0 — CHS<4:0>
GO/DONE
ADON -000 0000 -000 0000
09Eh ADCON1 ADFM ADCS<2:0> — —
ADPREF<1:0>
0000 --00 0000 --00
09Fh —Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 33
PIC12F/LF1822/16F/LF1823
Bank 2
100h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
101h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
102h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
103h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
104h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
105h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
106h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
107h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
108h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
109h(1) WREG Working Register 0000 0000 uuuu uuuu
10Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
10Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
10Ch LATA ——LATA5LATA4—LATA2LATA1LATA0--xx -xxx --uu -uuu
10Dh —Unimplemented — —
10Eh LATC(2) —— LATC5 LATC4 LATC3 LATC2 LATC1 LATC0 --xx xxxx --uu uuuu
10Fh —Unimplemented — —
110h —Unimplemented — —
111h CM1CON0 C1ON C1OUT C1OE C1POL — C1SP C1HYS C1SYNC 0000 -100 0000 -100
112h CM1CON1 C1INTP C1INTN C1PCH<1:0> — — C1NCH1(2) C1NCH0 0000 ---0 0000 ---0
113h CM2CON0(2) C2ON C2OUT C2OE C2POL — C2SP C2HYS C2SYNC 0000 -100 0000 -100
114h CM2CON1(2) C2INTP C2INTN C2PCH<1:0> —— C2NCH<1:0> 0000 --00 0000 --00
115h CMOUT — — — — — —MC2OUT
(2) MC1OUT ---- --00 ---- --00
116h BORCON SBOREN — — — — — — BORRDY 1--- ---q u--- ---u
117h FVRCON FVREN FVRRDY Reserved Reserved CDAFVR<1:0> ADFVR<1:0> 0qrr 0000 0qrr 0000
118h DACCON0 DACEN DACLPS DACOE --- DACPSS<1:0> --- --- 000- 00-- 000- 00--
119h DACCON1 --- --- --- DACR<4:0> ---0 0000 ---0 0000
11Ah SRCON0 SRLEN SRCLK<2:0> SRQEN SRNQEN SRPS SRPR 0000 0000 0000 0000
11Bh SRCON1 SRSPE SRSCKE SRSC2E(2) SRSC1E SRRPE SRRCKE SRRC2E
(2) SRRC1E 0000 0000 0000 0000
11Ch —Unimplemented — —
11Dh APFCON RXDTSEL SDOSEL SSSEL --- T1GSEL TXCKSEL P1BSEL CCP1SEL 000- 0000 000- 0000
11Eh —Unimplemented — —
11Fh —Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 34 Preliminary 2010 Microchip Technology Inc.
Bank 3
180h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
181h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
182h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
183h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
184h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
185h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
186h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
187h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
188h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
189h(1) WREG Working Register 0000 0000 uuuu uuuu
18Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
18Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
18Ch ANSELA — — — ANSA4 — ANSA2 ANSA1 ANSA0 ---1 -111 ---1 -111
18Dh —Unimplemented — —
18Eh ANSELC(2) — — — — ANSC3 ANSC2 ANSC1 ANSC0 ---- 1111 ---- 1111
18Fh —Unimplemented — —
190h —Unimplemented — —
191h EEADRL EEPROM / Program Memory Address Register Low Byte 0000 0000 0000 0000
192h EEADRH — EEPROM / Program Memory Address Register High Byte -000 0000 -000 0000
193h EEDATL EEPROM / Program Memory Read Data Register Low Byte xxxx xxxx uuuu uuuu
194h EEDATH —— EEPROM / Program Memory Read Data Register High Byte --xx xxxx --uu uuuu
195h EECON1 EEPGD CFGS LWLO FREE WRERR WREN WR RD 0000 x000 0000 q000
196h EECON2 EEPROM control register 2 0000 0000 0000 0000
197h —Unimplemented — —
198h —Unimplemented — —
199h RCREG USART Receive Data Register 0000 0000 0000 0000
19Ah TXREG USART Transmit Data Register 0000 0000 0000 0000
19Bh SPBRGL Baud Rate Generator Data Register Low 0000 0000 0000 0000
19Ch SPBRGH Baud Rate Generator Data Register High 0000 0000 0000 0000
19Dh RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x
19Eh TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 0000 0010 0000 0010
19Fh BAUDCON ABDOVF RCIDL — SCKP BRG16 —WUEABDEN01-0 0-00 01-0 0-00
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 35
PIC12F/LF1822/16F/LF1823
Bank 4
200h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
201h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
202h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
203h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
204h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
205h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
206h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
207h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
208h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
209h(1) WREG Working Register 0000 0000 uuuu uuuu
20Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
20Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
20Ch WPUA —— WPUA5 WPUA4 WPUA3 WPUA2 WPUA1 WPUA0 --11 1111 --11 1111
20Dh —Unimplemented — —
20Eh WPUC(2) —— WPUC5 WPUC4 WPUC3 WPUC2 WPUC1 WPUC0 --11 1111 --11 1111
20Fh —Unimplemented — —
210h —Unimplemented — —
211h SSP1BUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu
212h SSP1ADD ADD<7:0> 0000 0000 0000 0000
213h SSP1MSK MSK<7:0> 1111 1111 1111 1111
214h SSP1STAT SMP CKE D/A PSR/WUA BF 0000 0000 0000 0000
215h SSP1CON1 WCOL SSPOV SSPEN CKP SSPM<3:0> 0000 0000 0000 0000
216h SSP1CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 0000 0000 0000 0000
217h SSP1CON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN 0000 0000 0000 0000
218h —Unimplemented — —
219h —Unimplemented — —
21Ah —Unimplemented — —
21Bh —Unimplemented — —
21Ch —Unimplemented — —
21Dh —Unimplemented — —
21Eh —Unimplemented — —
21Fh —Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 36 Preliminary 2010 Microchip Technology Inc.
Bank 5
280h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
281h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
282h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
283h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
284h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
285h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
286h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
287h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
288h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
289h(1) WREG Working Register 0000 0000 uuuu uuuu
28Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
28Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
28Ch —Unimplemented — —
28Dh —Unimplemented — —
28Eh —Unimplemented — —
28Fh —Unimplemented — —
290h —Unimplemented — —
291h CCPR1L Capture/Compare/PWM Register 1 (LSB) xxxx xxxx uuuu uuuu
292h CCPR1H Capture/Compare/PWM Register 1 (MSB) xxxx xxxx uuuu uuuu
293h CCP1CON P1M<1:0> DC1B<1:0> CCP1M<3:0> 0000 0000 0000 0000
294h PWM1CON P1RSEN P1DC<6:0> 0000 0000 0000 0000
295h CCP1AS CCP1ASE CCP1AS<2:0> PSS1AC<1:0> PSS1BD<1:0> 0000 0000 0000 0000
296h PSTR1CON — — — STR1SYNC STR1D STR1C STR1B STR1A ---0 0001 ---0 0001
297h —Unimplemented — —
298h —Unimplemented — —
299h —Unimplemented — —
29Ah —Unimplemented — —
29Bh —Unimplemented — —
29Ch —Unimplemented — —
29Dh —Unimplemented — —
29Eh —Unimplemented — —
29Fh —Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 37
PIC12F/LF1822/16F/LF1823
Bank 6
300h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
301h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
302h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
303h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
304h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
305h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
306h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
307h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
308h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
309h(1) WREG Working Register 0000 0000 uuuu uuuu
30Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
30Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
30Ch —Unimplemented — —
30Dh —Unimplemented — —
30Eh —Unimplemented — —
30Fh —Unimplemented — —
310h —Unimplemented — —
311h —Unimplemented — —
312h —Unimplemented — —
313h —Unimplemented — —
314h —Unimplemented — —
315h —Unimplemented — —
316h —Unimplemented — —
317h —Unimplemented — —
318h —Unimplemented — —
319h —Unimplemented — —
31Ah —Unimplemented — —
31Bh —Unimplemented — —
31Ch —Unimplemented — —
31Dh —Unimplemented — —
31Eh —Unimplemented — —
31Fh —Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 38 Preliminary 2010 Microchip Technology Inc.
Bank 7
380h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
381h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
382h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
383h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
384h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
385h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
386h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
387h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
388h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
389h(1) WREG Working Register 0000 0000 uuuu uuuu
38Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
38Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
38Ch —Unimplemented — —
38Dh —Unimplemented — —
38Eh —Unimplemented — —
38Fh —Unimplemented — —
390h —Unimplemented — —
391h IOCAP —— IOCAP5 IOCAP4 IOCAP3
IOCAP2 IOCAP1 IOCAP0
--00 0000 --00 0000
392h IOCAN —— IOCAN5 IOCAN4 IOCAN3
IOCAN2 IOCAN1 IOCAN0
--00 0000 --00 0000
393h IOCAF —— IOCAF5 IOCAF4 IOCAF3
IOCAF2 IOCAF1 IOCAF0
--00 0000 --00 0000
394h —Unimplemented — —
395h —Unimplemented — —
396h —Unimplemented — —
397h —Unimplemented — —
398h —Unimplemented — —
399h —Unimplemented — —
39Ah CLKRCON CLKREN CLKROE CLKRSLR CLKRDC<1:0>
CLKRDIV
<2:0> 0011 0000 0011 0000
39Bh —Unimplemented — —
39Ch MDCON MDEN MDOE MDSLR MDOPOL MDOUT — —
MDBIT
0010 ---0 0010 ---0
39Dh MDSRC MDMSODIS — — —
MDMS<3:0>
x--- xxxx u--- uuuu
39Eh MDCARL MDCLODIS MDCLPOL MDCLSYNC —
MDCL<3:0>
xxx- xxxx uuu- uuuu
39Fh MDCARH MDCHODIS MDCHPOL MDCHSYNC —
MDCH<3:0>
xxx- xxxx uuu- uuuu
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 39
PIC12F/LF1822/16F/LF1823
Bank 8
400h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
401h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
402h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
403h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
404h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
405h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
406h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
407h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
408h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
409h(1) WREG Working Register 0000 0000 uuuu uuuu
40Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
40Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
40Ch —Unimplemented — —
40Dh —Unimplemented — —
40Eh —Unimplemented — —
40Fh —Unimplemented — —
410h —Unimplemented — —
411h —Unimplemented — —
412h —Unimplemented — —
413h —Unimplemented — —
414h —Unimplemented — —
415h —Unimplemented — —
416h —Unimplemented — —
417h —Unimplemented — —
418h —Unimplemented — —
419h —Unimplemented — —
41Ah —Unimplemented — —
41Bh —Unimplemented — —
41Ch —Unimplemented — —
41Dh —Unimplemented — —
41Eh —Unimplemented — —
41Fh —Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 40 Preliminary 2010 Microchip Technology Inc.
Banks 9-30
x00h/
x80h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
x00h/
x81h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
x02h/
x82h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
x03h/
x83h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
x04h/
x84h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
x05h/
x85h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
x06h/
x86h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
x07h/
x87h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
x08h/
x88h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
x09h/
x89h(1) WREG Working Register 0000 0000 uuuu uuuu
x0Ah/
x8Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
x0Bh/
x8Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
x0Ch/
x8Ch
—
x1Fh/
x9Fh
—Unimplemented — —
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 41
PIC12F/LF1822/16F/LF1823
Bank 31
F80h(1) INDF0 Addressing this location uses contents of FSR0H/FSR0L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
F81h(1) INDF1 Addressing this location uses contents of FSR1H/FSR1L to address data memory
(not a physical register)
xxxx xxxx xxxx xxxx
F82h(1) PCL Program Counter (PC) Least Significant Byte 0000 0000 0000 0000
F83h(1) STATUS — — —TOPD ZDCC---1 1000 ---q quuu
F84h(1) FSR0L Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu
F85h(1) FSR0H Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000
F86h(1) FSR1L Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu
F87h(1) FSR1H Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000
F88h(1) BSR — — — BSR<4:0> ---0 0000 ---0 0000
F89h(1) WREG Working Register 0000 0000 uuuu uuuu
F8Ah(1) PCLATH — Write Buffer for the upper 7 bits of the Program Counter -000 0000 -000 0000
F8Bh(1) INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 0000 000x 0000 000u
F8Ch
—
FE3h
—Unimplemented — —
FE4h STATUS_
SHAD
— — — — —ZDCC---- -xxx ---- -uuu
FE5h WREG_
SHAD
Working Register Shadow 0000 0000 uuuu uuuu
FE6h BSR_
SHAD
— — — Bank Select Register Shadow ---x xxxx ---u uuuu
FE7h PCLATH_
SHAD
— Program Counter Latch High Register Shadow -xxx xxxx uuuu uuuu
FE8h FSR0L_
SHAD
Indirect Data Memory Address 0 Low Pointer Shadow xxxx xxxx uuuu uuuu
FE9h FSR0H_
SHAD
Indirect Data Memory Address 0 High Pointer Shadow xxxx xxxx uuuu uuuu
FEAh FSR1L_
SHAD
Indirect Data Memory Address 1 Low Pointer Shadow xxxx xxxx uuuu uuuu
FEBh FSR1H_
SHAD
Indirect Data Memory Address 1 High Pointer Shadow xxxx xxxx uuuu uuuu
FECh —Unimplemented — —
FEDh STKPTR — — — Current Stack pointer ---1 1111 ---1 1111
FEEh TOSL Top-of-Stack Low byte xxxx xxxx uuuu uuuu
FEFh TOSH — Top-of-Stack High byte -xxx xxxx -uuu uuuu
TABLE 3-8: SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED)
Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on:
POR, BOR
Value on all
other
resets
Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved.
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 42 Preliminary 2010 Microchip Technology Inc.
3.3 PCL and PCLATH
The Program Counter (PC) is 15 bits wide. The low byte
comes from the PCL register, which is a readable and
writable register. The high byte (PC<14:8>) is not directly
readable or writable and comes from PCLATH. On any
Reset, the PC is cleared. Figure 3-3 shows the five
situations for the loading of the PC.
FIGURE 3-3: LOADING OF PC IN
DIFFERENT SITUATIONS
3.3.1 MODIFYING PCL
Executing any instruction with the PCL register as the
destination simultaneously causes the Program Coun-
ter PC<14:8> bits (PCH) to be replaced by the contents
of the PCLATH register. This allows the entire contents
of the program counter to be changed by writing the
desired upper 7 bits to the PCLATH register. When the
lower 8 bits are written to the PCL register, all 15 bits of
the program counter will change to the values con-
tained in the PCLATH register and those being written
to the PCL register.
3.3.2 COMPUTED GOTO
A computed GOTO is accomplished by adding an offset to
the program counter (ADDWF PCL). When performing a
table read using a computed GOTO method, care should
be exercised if the table location crosses a PCL memory
boundary (each 256-byte block). Refer to the Application
Note AN556, “Implementing a Table Read” (DS00556).
3.3.3 COMPUTED FUNCTION CALLS
A computed function CALL allows programs to maintain
tables of functions and provide another way to execute
state machines or look-up tables. When performing a
table read using a computed function CALL, care
should be exercised if the table location crosses a PCL
memory boundary (each 256-byte block).
If using the CALL instruction, the PCH<2:0> and PCL
registers are loaded with the operand of the CALL
instruction. PCH<6:3> is loaded with PCLATH<6:3>.
The CALLW instruction enables computed calls by com-
bining PCLATH and W to form the destination address.
A computed CALLW is accomplished by loading the W
register with the desired address and executing CALLW.
The PCL register is loaded with the value of W and
PCH is loaded with PCLATH.
3.3.4 BRANCHING
The branching instructions add an offset to the PC.
This allows relocatable code and code that crosses
page boundaries. There are two forms of branching,
BRW and BRA. The PC will have incremented to fetch
the next instruction in both cases. When using either
branching instruction, a PCL memory boundary may be
crossed.
If using BRW, load the W register with the desired
unsigned address and execute BRW. The entire PC will
be loaded with the address PC + 1 + W.
If using BRA, the entire PC will be loaded with PC + 1 +,
the signed value of the operand of the BRA instruction.
PCLPCH 0
14
PC
06 7
ALU Result
8
PCLATH
PCLPCH 0
14
PC
06 4
OPCODE <10:0>
11
PCLATH
PCLPCH 0
14
PC
06 7
W
8
PCLATH
Instruction with
PCL as
Destination
GOTO, CALL
CALLW
PCL
PCH 0
14
PC
PC + W
15
BRW
PCLPCH 0
14
PC
PC + OPCODE <8:0>
15
BRA
2010 Microchip Technology Inc. Preliminary DS41413A-page 43
PIC12F/LF1822/16F/LF1823
3.4 Stack
All devices have a 16-level x 15-bit wide hardware
stack (refer to Figures 3-4 through and 3-7). The stack
space is not part of either program or data space. The
PC is PUSHed onto the stack when CALL or CALLW
instructions are executed or an interrupt causes a
branch. The stack is POPed in the event of a RETURN,
RETLW or a RETFIE instruction execution. PCLATH is
not affected by a PUSH or POP operation.
The stack operates as a circular buffer if the STVREN
bit = 0 (Configuration Word 2). This means that after
the stack has been PUSHed sixteen times, the seven-
teenth PUSH overwrites the value that was stored from
the first PUSH. The eighteenth PUSH overwrites the
second PUSH (and so on). The STKOVF and STKUNF
flag bits will be set on an Overflow/Underflow, regard-
less of whether the Reset is enabled.
3.4.1 ACCESSING THE STACK
The stack is available through the TOSH, TOSL and
STKPTR registers. STKPTR is the current value of the
Stack Pointer. TOSH:TOSL register pair points to the
TOP of the stack. Both registers are read/writable. TOS
is split into TOSH and TOSL due to the 15-bit size of the
PC. To access the stack, adjust the value of STKPTR,
which will position TOSH:TOSL, then read/write to
TOSH:TOSL. STKPTR is 5 bits to allow detection of
overflow and underflow.
During normal program operation, CALL, CALLW and
Interrupts will increment STKPTR while RETLW,
RETURN, and RETFIE will decrement STKPTR. At any
time STKPTR can be inspected to see how much stack
is left. The STKPTR always points at the currently used
place on the stack. Therefore, a CALL or CALLW will
increment the STKPTR and then write the PC, and a
return will unload the PC and then decrement STKPTR.
Reference Figure 3-4 through Figure 3-7 for examples
of accessing the stack.
FIGURE 3-4: ACCESSING THE STACK EXAMPLE 1
Note 1: There are no instructions/mnemonics
called PUSH or POP. These are actions
that occur from the execution of the
CALL, CALLW, RETURN, RETLW and
RETFIE instructions or the vectoring to
an interrupt address.
Note: Care should be taken when modifying the
STKPTR while interrupts are enabled.
0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
0x00
0x0000
STKPTR = 0x1F
Initial Stack Configuration:
After Reset, the stack is empty. The
empty stack is initialized so the Stack
Pointer is pointing at 0x1F. If the Stack
Overflow/Underflow Reset is enabled, the
TOSH/TOSL registers will return ‘0’. If
the Stack Overflow/Underflow Reset is
disabled, the TOSH/TOSL registers will
return the contents of stack address 0x0F.
0x1F STKPTR = 0x1F
Stack Reset Disabled
(STVREN = 0)
Stack Reset Enabled
(STVREN = 1)
TOSH:TOSL
TOSH:TOSL
PIC12F/LF1822/16F/LF1823
DS41413A-page 44 Preliminary 2010 Microchip Technology Inc.
FIGURE 3-5: ACCESSING THE STACK EXAMPLE 2
FIGURE 3-6: ACCESSING THE STACK EXAMPLE 3
0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
Return Address0x00 STKPTR = 0x00
This figure shows the stack configuration
after the first CALL or a single interrupt.
If a RETURN instruction is executed, the
return address will be placed in the
Program Counter and the Stack Pointer
decremented to the empty state (0x1F).
TOSH:TOSL
0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
0x09
0x08
0x07
Return Address0x06
Return Address0x05
Return Address0x04
Return Address0x03
Return Address0x02
Return Address0x01
Return Address0x00
STKPTR = 0x06
After seven CALLs or six CALLs and an
interrupt, the stack looks like the figure
on the left. A series of RETURN instructions
will repeatedly place the return addresses
into the Program Counter and pop the stack.
TOSH:TOSL
2010 Microchip Technology Inc. Preliminary DS41413A-page 45
PIC12F/LF1822/16F/LF1823
FIGURE 3-7: ACCESSING THE STACK EXAMPLE 4
3.4.2 OVERFLOW/UNDERFLOW RESET
If the STVREN bit in Configuration Word 2 is set to ‘1’,
the device will be reset if the stack is PUSHed beyond
the sixteenth level or POPed beyond the first level,
setting the appropriate bits (STKOVF or STKUNF,
respectively) in the PCON register.
3.5 Indirect Addressing
The INDFn registers are not physical registers. Any
instruction that accesses an INDFn register actually
accesses the register at the address specified by the
File Select Registers (FSR). If the FSRn address
specifies one of the two INDFn registers, the read will
return ‘0’ and the write will not occur (though Status bits
may be affected). The FSRn register value is created
by the pair FSRnH and FSRnL.
The FSR registers form a 16-bit address that allows an
addressing space with 65536 locations. These locations
are divided into three memory regions:
• Traditional Data Memory
• Linear Data Memory
• Program Flash Memory
0x0F
0x0E
0x0D
0x0C
0x0B
0x0A
0x09
0x08
0x07
0x06
0x05
0x04
0x03
0x02
0x01
Return Address0x00 STKPTR = 0x10
When the stack is full, the next CALL or
an interrupt will set the Stack Pointer to
0x10. This is identical to address 0x00
so the stack will wrap and overwrite the
return address at 0x00. If the Stack
Overflow/Underflow Reset is enabled, a
Reset will occur and location 0x00 will
not be overwritten.
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
Return Address
TOSH:TOSL
PIC12F/LF1822/16F/LF1823
DS41413A-page 46 Preliminary 2010 Microchip Technology Inc.
FIGURE 3-8: INDIRECT ADDRESSING
0x0000
0x0FFF
Traditional
FSR
Address
Range
Data Memory
0x1000 Reserved
Linear
Data Memory
Reserved
0x2000
0x29AF
0x29B0
0x7FFF
0x8000
0xFFFF
0x0000
0x0FFF
0x0000
0x7FFF
Program
Flash Memory
Note: Not all memory regions are completely implemented. Consult device memory tables for memory limits.
0x1FFF
2010 Microchip Technology Inc. Preliminary DS41413A-page 47
PIC12F/LF1822/16F/LF1823
3.5.1 TRADITIONAL DATA MEMORY
The traditional data memory is a region from FSR
address 0x000 to FSR address 0xFFF. The addresses
correspond to the absolute addresses of all SFR, GPR
and common registers.
FIGURE 3-9: TRADITIONAL DATA MEMORY MAP
Indirect AddressingDirect Addressing
Bank Select Location Select
4 BSR 6 0
From Opcode FSRxL70
Bank Select Location Select
0000 0001 0010 1111
0x00
0x7F
Bank 0 Bank 1 Bank 2 Bank 31
0FSRxH70
0000
PIC12F/LF1822/16F/LF1823
DS41413A-page 48 Preliminary 2010 Microchip Technology Inc.
3.5.2 LINEAR DATA MEMORY
The linear data memory is the region from FSR
address 0x2000 to FSR address 0x29AF. This region is
a virtual region that points back to the 80-byte blocks of
GPR memory in all the banks.
Unimplemented memory reads as 0x00. Use of the
linear data memory region allows buffers to be larger
than 80 bytes because incrementing the FSR beyond
one bank will go directly to the GPR memory of the next
bank.
The 16 bytes of common memory are not included in
the linear data memory region.
FIGURE 3-10: LINEAR DATA MEMORY
MAP
3.5.3 PROGRAM FLASH MEMORY
To make constant data access easier, the entire
program Flash memory is mapped to the upper half of
the FSR address space. When the MSB of FSRnH is
set, the lower 15 bits are the address in program
memory which will be accessed through INDF. Only the
lower 8 bits of each memory location is accessible via
INDF. Writing to the program Flash memory cannot be
accomplished via the FSR/INDF interface. All
instructions that access program Flash memory via the
FSR/INDF interface will require one additional
instruction cycle to complete.
FIGURE 3-11: PROGRAM FLASH
MEMORY MAP
7
01
7
00
Location Select 0x2000
FSRnH FSRnL
0x020
Bank 0
0x06F
0x0A0
Bank 1
0x0EF
0x120
Bank 2
0x16F
0xF20
Bank 30
0xF6F
0x29AF
0
7
1
7
00
Location Select 0x8000
FSRnH FSRnL
0x0000
0x7FFF
0xFFFF
Program
Flash
Memory
(low 8
bits)
2010 Microchip Technology Inc. Preliminary DS41413A-page 49
PIC12F/LF1822/16F/LF1823
4.0 DEVICE CONFIGURATION
Device Configuration consists of Configuration Word 1
and Configuration Word 2, Code Protection and Device
ID.
4.1 Configuration Words
There are several Configuration Word bits that allow
different oscillator and memory protection options.
These are implemented as Configuration Word 1 at
8007h and Configuration Word 2 at 8008h.
PIC12F/LF1822/16F/LF1823
DS41413A-page 50 Preliminary 2010 Microchip Technology Inc.
REGISTER 4-1: CONFIGURATION WORD 1
R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1
FCMEN IESO CLKOUTEN BOREN1 BOREN0 CPD CP
bit 13 bit 7
R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1 R/P-1/1
MCLRE PWRTE WDTE1 WDTE0 FOSC2 FOSC1 FOSC0
bit 6 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared P = Programmable bit
bit 13 FCMEN: Fail-Safe Clock Monitor Enable bit
1 = Fail-Safe Clock Monitor is enabled
0 = Fail-Safe Clock Monitor is disabled
bit 12 IESO: Internal External Switchover bit
1 = Internal/External Switchover mode is enabled
0 = Internal/External Switchover mode is disabled
bit 11 CLKOUTEN: Clock Out Enable bit
If FOSC configuration bits are set to LP, XT, HS modes:
This bit is ignored, CLKOUT function is disabled. Oscillator function on the CLKOUT pin.
All other FOSC modes:
1 = CLKOUT function is disabled. I/O function on the CLKOUT pin.
0 = CLKOUT function is enabled on the CLKOUT pin
bit 10-9 BOREN<1:0>: Brown-out Reset Enable bits(1)
11 = BOR enabled
10 = BOR enabled during operation and disabled in Sleep
01 = BOR controlled by SBOREN bit of the BORCON register
00 = BOR disabled
bit 8 CPD: Data Code Protection bit(2)
1 = Data memory code protection is disabled
0 = Data memory code protection is enabled
bit 7 CP: Code Protection bit(3)
1 = Program memory code protection is disabled
0 = Program memory code protection is enabled
bit 6 MCLRE: RA3/MCLR/VPP Pin Function Select bit
If LVP bit = 1:
This bit is ignored.
If LVP bit = 0:
1 =MCLR
/VPP pin function is MCLR; Weak pull-up enabled.
0 =MCLR
/VPP pin function is digital input; MCLR internally disabled; Weak pull-up under control of
WPUA register.
bit 5 PWRTE: Power-up Timer Enable bit(1)
1 = PWRT disabled
0 = PWRT enabled
bit 4-3 WDTE<1:0>: Watchdog Timer Enable bit
11 = WDT enabled
10 = WDT enabled while running and disabled in Sleep
01 = WDT controlled by the SWDTEN bit in the WDTCON register
00 = WDT disabled
Note 1: Enabling Brown-out Reset does not automatically enable Power-up Timer.
2: The entire data EEPROM will be erased when the code protection is turned off during an erase.
3: The entire program memory will be erased when the code protection is turned off.
2010 Microchip Technology Inc. Preliminary DS41413A-page 51
PIC12F/LF1822/16F/LF1823
bit 2-0 FOSC<2:0>: Oscillator Selection bits
111 = ECH: External Clock, High-Power mode (4-32 MHz): device clock supplied to CLKIN pin
110 = ECM: External Clock, Medium-Power mode (0.5-4 MHz): device clock supplied to CLKIN pin
101 = ECL: External Clock, Low-Power mode (0-0.5 MHz): device clock supplied to CLKIN pin
100 = INTOSC oscillator: I/O function on CLKIN pin
011 = EXTRC oscillator: External RC circuit connected to CLKIN pin
010 = HS oscillator: High-speed crystal/resonator connected between OSC1 and OSC2 pins
001 = XT oscillator: Crystal/resonator connected between OSC1 and OSC2 pins
000 = LP oscillator: Low-power crystal connected between OSC1 and OSC2 pins
REGISTER 4-1: CONFIGURATION WORD 1 (CONTINUED)
Note 1: Enabling Brown-out Reset does not automatically enable Power-up Timer.
2: The entire data EEPROM will be erased when the code protection is turned off during an erase.
3: The entire program memory will be erased when the code protection is turned off.
PIC12F/LF1822/16F/LF1823
DS41413A-page 52 Preliminary 2010 Microchip Technology Inc.
REGISTER 4-2: CONFIGURATION WORD 2
R/P-1/1 R/P-1/1 U-1 R/P-1/1 R/P-1/1 R/P-1/1 U-1
LVP DEBUG — BORV STVREN PLLEN —
bit 13 bit 7
U-1 U-1 R-1 U-1 U-1 R/P-1/1 R/P-1/1
— — Reserved ——WRT1WRT0
bit 6 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared P = Programmable bit
bit 13 LVP: Low-Voltage Programming Enable bit(1)
1 = Low-voltage programming enabled
0 = High-voltage on MCLR must be used for programming
bit 12 DEBUG: In-Circuit Debugger Mode bit
1 = In-Circuit Debugger disabled, ICSPCLK and ICSPDAT are general purpose I/O pins
0 = In-Circuit Debugger enabled, ICSPCLK and ICSPDAT are dedicated to the debugger
bit 11 Unimplemented: Read as ‘1’
bit 10 BORV: Brown-out Reset Voltage Selection bit
1 = Brown-out Reset voltage set to 1.9V (typical)
0 = Brown-out Reset voltage set to 2.5V (typical)
bit 9 STVREN: Stack Overflow/Underflow Reset Enable bit
1 = Stack Overflow or Underflow will cause a Reset
0 = Stack Overflow or Underflow will not cause a Reset
bit 8 PLLEN: PLL Enable bit
1 = 4xPLL enabled
0 = 4xPLL disabled
bit 7-5 Unimplemented: Read as ‘1’
bit 4 Reserved: This location should be programmed to a ‘1’.
bit 3-2 Unimplemented: Read as ‘1’
bit 1-0 WRT<1:0>: Flash Memory Self-Write Protection bits
11 = Write protection off
10 = 000h to 1FFh write-protected, 200h to 7FFh may be modified by EECON control
01 = 000h to 3FFh write-protected, 400h to 7FFh may be modified by EECON control
00 = 000h to 7FFh write-protected, no addresses may be modified by EECON control
Note 1: The LVP bit cannot be programmed to ‘0’ when Programming mode is entered via LVP.
2010 Microchip Technology Inc. Preliminary DS41413A-page 53
PIC12F/LF1822/16F/LF1823
4.2 Code Protection
Code protection allows the device to be protected from
unauthorized access. Program memory protection and
data EEPROM protection are controlled independently.
Internal access to the program memory and data
EEPROM are unaffected by any code protection
setting.
4.2.1 PROGRAM MEMORY PROTECTION
The entire program memory space is protected from
external reads and writes by the CP bit in Configuration
Word 1. When CP = 0, external reads and writes of
program memory are inhibited and a read will return all
‘0’s. The CPU can continue to read program memory,
regardless of the protection bit settings. Writing the
program memory is dependent upon the write
protection setting. See Section 4.3 “Write
Protection” for more information.
4.2.2 DATA EEPROM PROTECTION
The entire data EEPROM is protected from external
reads and writes by the CPD bit. When CPD = 0,
external reads and writes of data EEPROM are
inhibited. The CPU can continue to read and write data
EEPROM regardless of the protection bit settings.
4.3 Write Protection
Write protection allows the device to be protected from
unintended self-writes. Applications, such as
bootloader software, can be protected while allowing
other regions of the program memory to be modified.
The WRT<1:0> bits in Configuration Word 2 define the
size of the program memory block that is protected.
4.4 User ID
Four memory locations (8000h-8003h) are designated as
ID locations where the user can store checksum or other
code identification numbers. These locations are
readable and writable during normal execution. See
Section 11.5 “User ID, Device ID and Configuration
Word Access” for more information on accessing these
memory locations. For more information on checksum
calculation, see the “PIC16F/LF1826/27/PIC12F/LF1822
Memory Programming Specification” (DS41390).
PIC12F/LF1822/16F/LF1823
DS41413A-page 54 Preliminary 2010 Microchip Technology Inc.
4.5 Device ID and Revision ID
The memory location 8006h is where the Device ID and
Revision ID are stored. The upper nine bits hold the
Device ID. The lower five bits hold the Revision ID. See
Section 11.5 “User ID, Device ID and Configuration
Word Access” for more information on accessing
these memory locations.
Development tools, such as device programmers and
debuggers, may be used to read the Device ID and
Revision ID.
REGISTER 4-3: DEVICEID: DEVICE ID REGISTER(1)
RRRRRRR
DEV8 DEV7 DEV6 DEV5 DEV4 DEV3 DEV2
bit 13 bit 7
RRRRRRR
DEV1 DEV0 REV4 REV3 REV2 REV1 REV0
bit 6 bit 0
Legend: U = Unimplemented bit, read as ‘0’
R = Readable bit W = Writable bit ‘0’ = Bit is cleared
-n = Value at POR ‘1’ = Bit is set x = Bit is unknown
bit 13-5 DEV<8:0>: Device ID bits
100111100 = PIC12F1822
100111101 = PIC16F1823
101000100 = PIC12LF1822
101000101 = PIC16LF1823
bit 4-0 REV<4:0>: Revision ID bits
These bits are used to identify the revision.
Note 1: This location cannot be written.
2010 Microchip Technology Inc. Preliminary DS41413A-page 55
PIC12F/LF1822/16F/LF1823
5.0 OSCILLATOR MODULE (WITH
FAIL-SAFE CLOCK MONITOR)
5.1 Overview
The oscillator module has a wide variety of clock
sources and selection features that allow it to be used
in a wide range of applications while maximizing perfor-
mance and minimizing power consumption. Figure 5-1
illustrates a block diagram of the oscillator module.
Clock sources can be supplied from external oscillators,
quartz crystal resonators, ceramic resonators and
Resistor-Capacitor (RC) circuits. In addition, the system
clock source can be supplied from one of two internal
oscillators and PLL circuits, with a choice of speeds
selectable via software. Additional clock features
include:
• Selectable system clock source between external
or internal sources via software.
• Two-Speed Start-up mode, which minimizes
latency between external oscillator start-up and
code execution.
• Fail-Safe Clock Monitor (FSCM) designed to
detect a failure of the external clock source (LP,
XT, HS, EC or RC modes) and switch
automatically to the internal oscillator.
• Oscillator Start-up Timer (OST) ensures stability
of crystal oscillator sources
The oscillator module can be configured in one of six
clock modes.
1. EC – External clock (ECL, ECM, ECH. See
Section 5.2.1.1 “EC Mode”).
2. LP – 32 kHz Low-Power Crystal mode.
3. XT – Medium Gain Crystal or Ceramic Resonator
Oscillator mode.
4. HS – High Gain Crystal or Ceramic Resonator
mode.
5. RC – External Resistor-Capacitor (RC).
6. INTOSC – Internal oscillator.
Clock Source modes are selected by the FOSC<2:0>
bits in the Configuration Word 1. The FOSC bits
determine the type of oscillator that will be used when
the device is first powered.
The EC clock mode relies on an external logic level
signal as the device clock source. The LP, XT, and HS
clock modes require an external crystal or resonator to
be connected to the device. Each mode is optimized for
a different frequency range. The RC clock mode
requires an external resistor and capacitor to set the
oscillator frequency.
The INTOSC internal oscillator block produces low,
medium, and high frequency clock sources, designated
LFINTOSC, MFINTOSC, and HFINTOSC. (see
Internal Oscillator Block, Figure 5-1). A wide selection
of device clock frequencies may be derived from these
three clock sources.
FIGURE 5-1: SIMPLIFIED PIC® MCU CLOCK SOURCE BLOCK DIAGRAM
4 x PLL
FOSC<2:0>
Oscillator
T1OSCEN
Enable
Oscillator
T1OSO
T1OSI
Clock Source Option
for other modules
OSC1
OSC2
Sleep
LP, XT, HS, RC, EC
T1OSC CPU and
Postscaler
MUX
MUX
16 MHz
8 MHz
4 MHz
2 MHz
1 MHz
250 kHz
500 kHz
IRCF<3:0>
31 kHz
500 kHz
Source
Internal
Oscillator
Block
WDT, PWRT, Fail-Safe Clock Monitor
16 MHz
Internal Oscillator
(HFINTOSC)
Clock
Control
SCS<1:0>
HFPLL
31 kHz (LFINTOSC)
Two-Speed Start-up and other modules
Oscillator
31 kHz
Source
500 kHz
(MFINTOSC)
125 kHz
31.25 kHz
62.5 kHz
FOSC<2:0> = 100
Peripherals
Sleep
External
Timer1
PIC12F/LF1822/16F/LF1823
DS41413A-page 56 Preliminary 2010 Microchip Technology Inc.
5.2 Clock Source Types
Clock sources can be classified as external or internal.
External clock sources rely on external circuitry for the
clock source to function. Examples are: oscillator mod-
ules (EC mode), quartz crystal resonators or ceramic
resonators (LP, XT and HS modes) and Resis-
tor-Capacitor (RC) mode circuits.
Internal clock sources are contained internally within
the oscillator module. The internal oscillator block has
two internal oscillators and a dedicated
phase-locked-loop (HFPLL) that are used to generate
three internal system clock sources: the 16 MHz
High-Frequency Internal Oscillator (HFINTOSC), 500
kHZ (MFINTOSC) and the 31 kHz Low-Frequency
Internal Oscillator (LFINTOSC).
The system clock can be selected between external or
internal clock sources via the System Clock Select
(SCS) bits in the OSCCON register. See Section 5.3
“Clock Switching” for additional information.
5.2.1 EXTERNAL CLOCK SOURCES
An external clock source can be used as the device
system clock by performing one of the following
actions:
• Program the FOSC<2:0> bits in the Configuration
Word 1 to select an external clock source that will
be used as the default system clock upon a
device Reset.
• Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to:
- Timer1 Oscillator during run-time, or
- An external clock source determined by the
value of the FOSC bits.
See Section 5.3 “Clock Switching”for more informa-
tion.
5.2.1.1 EC Mode
The External Clock (EC) mode allows an externally
generated logic level signal to be the system clock
source. When operating in this mode, an external clock
source is connected to the OSC1 input.
OSC2/CLKOUT is available for general purpose I/O or
CLKOUT. Figure 5-2 shows the pin connections for EC
mode.
EC mode has 3 power modes to select from through
Configuration Word 1:
• High-power, 4-32 MHz (FOSC = 111)
• Medium power, 0.5-4 MHz (FOSC = 110)
• Low-power, 0-0.5 MHz (FOSC = 101)
The Oscillator Start-up Timer (OST) is disabled when
EC mode is selected. Therefore, there is no delay in
operation after a Power-on Reset (POR) or wake-up
from Sleep. Because the PIC® MCU design is fully
static, stopping the external clock input will have the
effect of halting the device while leaving all data intact.
Upon restarting the external clock, the device will
resume operation as if no time had elapsed.
FIGURE 5-2: EXTERNAL CLOCK (EC)
MODE OPERATION
5.2.1.2 LP, XT, HS Modes
The LP, XT and HS modes support the use of quartz
crystal resonators or ceramic resonators connected to
OSC1 and OSC2 (Figure 5-3). The three modes select
a low, medium or high gain setting of the internal
inverter-amplifier to support various resonator types
and speed.
LP Oscillator mode selects the lowest gain setting of the
internal inverter-amplifier. LP mode current consumption
is the least of the three modes. This mode is designed to
drive only 32.768 kHz tuning-fork type crystals (watch
crystals).
XT Oscillator mode selects the intermediate gain
setting of the internal inverter-amplifier. XT mode
current consumption is the medium of the three modes.
This mode is best suited to drive resonators with a
medium drive level specification.
HS Oscillator mode selects the highest gain setting of the
internal inverter-amplifier. HS mode current consumption
is the highest of the three modes. This mode is best
suited for resonators that require a high drive setting.
Figure 5-3 and Figure 5-4 show typical circuits for
quartz crystal and ceramic resonators, respectively.
OSC1/CLKIN
OSC2/CLKOUT
Clock from
Ext. System
PIC® MCU
FOSC/4 or I/O(1)
Note 1: Output depends upon CLKOUTEN bit of the
Configuration Word 1.
2010 Microchip Technology Inc. Preliminary DS41413A-page 57
PIC12F/LF1822/16F/LF1823
FIGURE 5-3: QUARTZ CRYSTAL
OPERATION (LP, XT OR
HS MODE)
FIGURE 5-4: CERAMIC RESONATOR
OPERATION
(XT OR HS MODE)
5.2.1.3 Oscillator Start-up Timer (OST)
If the oscillator module is configured for LP, XT or HS
modes, the Oscillator Start-up Timer (OST) counts
1024 oscillations from OSC1. This occurs following a
Power-on Reset (POR) and when the Power-up Timer
(PWRT) has expired (if configured), or a wake-up from
Sleep. During this time, the program counter does not
increment and program execution is suspended. The
OST ensures that the oscillator circuit, using a quartz
crystal resonator or ceramic resonator, has started and
is providing a stable system clock to the oscillator
module.
In order to minimize latency between external oscillator
start-up and code execution, the Two-Speed Clock
Start-up mode can be selected (see Section 5.4
“Two-Speed Clock Start-up Mode”).
5.2.1.4 4X PLL
The oscillator module contains a 4X PLL that can be
used with both external and internal clock sources to
provide a system clock source. The input frequency for
the 4X PLL must fall within specifications. See the PLL
Clock Timing Specifications in Section 29.0
“Electrical Specifications”.
The 4X PLL may be enabled for use by one of two
methods:
1. Program the PLLEN bit in Configuration Word 2
to a ‘1’.
2. Write the SPLLEN bit in the OSCCON register to
a ‘1’. If the PLLEN bit in Configuration Word 2 is
programmed to a ‘1’, then the value of SPLLEN
is ignored.
Note 1: Quartz crystal characteristics vary according
to type, package and manufacturer. The
user should consult the manufacturer data
sheets for specifications and recommended
application.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
3: For oscillator design assistance, reference
the following Microchip Applications Notes:
• AN826, “Crystal Oscillator Basics and
Crystal Selection for rfPIC® and PIC®
Devices” (DS00826)
• AN849, “Basic PIC® Oscillator Design”
(DS00849)
• AN943, “Practical PIC® Oscillator
Analysis and Design” (DS00943)
• AN949, “Making Your Oscillator Work”
(DS00949)
Note 1: A series resistor (RS) may be required for
quartz crystals with low drive level.
2: The value of RF varies with the Oscillator mode
selected (typically between 2 M to 10 M.
C1
C2
Quartz
RS(1)
OSC1/CLKIN
RF(2) Sleep
To Internal
Logic
PIC® MCU
Crystal
OSC2/CLKOUT
Note 1: A series resistor (RS) may be required for
ceramic resonators with low drive level.
2: The value of RF varies with the Oscillator mode
selected (typically between 2 M to 10 M.
3: An additional parallel feedback resistor (RP)
may be required for proper ceramic resonator
operation.
C1
C2 Ceramic RS(1)
OSC1/CLKIN
RF(2) Sleep
To Internal
Logic
PIC® MCU
RP(3)
Resonator
OSC2/CLKOUT
PIC12F/LF1822/16F/LF1823
DS41413A-page 58 Preliminary 2010 Microchip Technology Inc.
5.2.1.5 TIMER1 Oscillator
The Timer1 Oscillator is a separate crystal oscillator
that is associated with the Timer1 peripheral. It is opti-
mized for timekeeping operations with a 32.768 kHz
crystal connected between the T1OSO and T1OSI
device pins.
The Timer1 Oscillator can be used as an alternate sys-
tem clock source and can be selected during run-time
using clock switching. Refer to Section 5.3 “Clock
Switching” for more information.
FIGURE 5-5: QUARTZ CRYSTAL
OPERATION (TIMER1
OSCILLATOR)
5.2.1.6 External RC Mode
The external Resistor-Capacitor (RC) modes support
the use of an external RC circuit. This allows the
designer maximum flexibility in frequency choice while
keeping costs to a minimum when clock accuracy is not
required.
The RC circuit connects to OSC1. OSC2/CLKOUT is
available for general purpose I/O or CLKOUT. The
function of the OSC2/CLKOUT pin is determined by the
state of the CLKOUTEN bit in Configuration Word 1.
Figure 5-6 shows the external RC mode connections.
FIGURE 5-6: EXTERNAL RC MODES
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT) values
and the operating temperature. Other factors affecting
the oscillator frequency are:
• threshold voltage variation
• component tolerances
• packaging variations in capacitance
The user also needs to take into account variation due
to tolerance of external RC components used.
Note 1: Quartz crystal characteristics vary according
to type, package and manufacturer. The
user should consult the manufacturer data
sheets for specifications and recommended
application.
2: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
3: For oscillator design assistance, reference
the following Microchip Applications Notes:
• AN826, “Crystal Oscillator Basics and
Crystal Selection for rfPIC® and PIC®
Devices” (DS00826)
• AN849, “Basic PIC® Oscillator Design”
(DS00849)
• AN943, “Practical PIC® Oscillator
Analysis and Design” (DS00943)
• AN949, “Making Your Oscillator Work”
(DS00949)
• TB097, “Interfacing a Micro Crystal
MS1V-T1K 32.768 kHz Tuning Fork
Crystal to a PIC16F690/SS” (DS91097)
• AN1288, “Design Practices for
Low-Power External Oscillators”
(DS01288)
C1
C2
32.768 kHz
T1OSI
To Internal
Logic
PIC® MCU
Crystal
T1OSO
Quartz
OSC2/CLKOUT
CEXT
REXT
PIC® MCU
OSC1/CLKIN
FOSC/4 or
Internal
Clock
VDD
VSS
Recommended values: 10 k REXT 100 k, <3V
3 k REXT 100 k, 3-5V
CEXT > 20 pF, 2-5V
Note 1: Output depends upon CLKOUTEN bit of the
Configuration Word 1.
I/O(1)
2010 Microchip Technology Inc. Preliminary DS41413A-page 59
PIC12F/LF1822/16F/LF1823
5.2.2 INTERNAL CLOCK SOURCES
The device may be configured to use the internal oscil-
lator block as the system clock by performing one of the
following actions:
• Program the FOSC<2:0> bits in Configuration
Word 1 to select the INTOSC clock source, which
will be used as the default system clock upon a
device Reset.
• Write the SCS<1:0> bits in the OSCCON register
to switch the system clock source to the internal
oscillator during run-time. See Section 5.3
“Clock Switching”for more information.
In INTOSC mode, OSC1/CLKIN is available for general
purpose I/O. OSC2/CLKOUT is available for general
purpose I/O or CLKOUT.
The function of the OSC2/CLKOUT pin is determined
by the state of the CLKOUTEN bit in Configuration
Word 1.
The internal oscillator block has two independent
oscillators and a dedicated Phase-Locked Loop,
HFPLL that can produce one of three internal system
clock sources.
1. The HFINTOSC (High-Frequency Internal
Oscillator) is factory calibrated and operates at
16 MHz. The HFINTOSC source is generated
from the 500 kHz MFINTOSC source and the
dedicated Phase-Locked Loop, HFPLL. The
frequency of the HFINTOSC can be
user-adjusted via software using the OSCTUNE
register (Register 5-3).
2. The MFINTOSC (Medium-Frequency Internal
Oscillator) is factory calibrated and operates at
500 kHz. The frequency of the MFINTOSC can
be user-adjusted via software using the
OSCTUNE register (Register 5-3).
3. The LFINTOSC (Low-Frequency Internal
Oscillator) is uncalibrated and operates at
31 kHz.
5.2.2.1 HFINTOSC
The High-Frequency Internal Oscillator (HFINTOSC) is
a factory calibrated 16 MHz internal clock source. The
frequency of the HFINTOSC can be altered via
software using the OSCTUNE register (Register 5-3).
The output of the HFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). One of nine
frequencies derived from the HFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See Section 5.2.2.7 “Internal
Oscillator Clock Switch Timing” for more information.
The HFINTOSC is enabled by:
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
•FOSC<2:0> = 100, or
• Set the System Clock Source (SCS) bits of the
OSCCON register to ‘1x’.
The High Frequency Internal Oscillator Ready bit
(HFIOFR) of the OSCSTAT register indicates when the
HFINTOSC is running and can be utilized.
The High Frequency Internal Oscillator Status Locked
bit (HFIOFL) of the OSCSTAT register indicates when
the HFINTOSC is running within 2% of its final value.
The High Frequency Internal Oscillator Status Stable
bit (HFIOFS) of the OSCSTAT register indicates when
the HFINTOSC is running within 0.5% of its final value.
5.2.2.2 MFINTOSC
The Medium-Frequency Internal Oscillator
(MFINTOSC) is a factory calibrated 500 kHz internal
clock source. The frequency of the MFINTOSC can be
altered via software using the OSCTUNE register
(Register 5-3).
The output of the MFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). One of nine
frequencies derived from the MFINTOSC can be
selected via software using the IRCF<3:0> bits of the
OSCCON register. See Section 5.2.2.7 “Internal
Oscillator Clock Switch Timing” for more information.
The MFINTOSC is enabled by:
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired HF frequency, and
•FOSC<2:0> = 100, or
• Set the System Clock Source (SCS) bits of the
OSCCON register to ‘1x’
The Medium Frequency Internal Oscillator Ready bit
(MFIOFR) of the OSCSTAT register indicates when the
MFINTOSC is running and can be utilized.
PIC12F/LF1822/16F/LF1823
DS41413A-page 60 Preliminary 2010 Microchip Technology Inc.
5.2.2.3 Internal Oscillator Frequency
Adjustment
The 500 kHz internal oscillator is factory calibrated.
This internal oscillator can be adjusted in software by
writing to the OSCTUNE register (Register 5-3). Since
the HFINTOSC and MFINTOSC clock sources are
derived from the 500 kHz internal oscillator a change in
the OSCTUNE register value will apply to both.
The default value of the OSCTUNE register is ‘0’. The
value is a 6-bit two’s complement number. A value of
1Fh will provide an adjustment to the maximum
frequency. A value of 20h will provide an adjustment to
the minimum frequency.
When the OSCTUNE register is modified, the oscillator
frequency will begin shifting to the new frequency. Code
execution continues during this shift. There is no
indication that the shift has occurred.
OSCTUNE does not affect the LFINTOSC frequency.
Operation of features that depend on the LFINTOSC
clock source frequency, such as the Power-up Timer
(PWRT), Watchdog Timer (WDT), Fail-Safe Clock
Monitor (FSCM) and peripherals, are not affected by the
change in frequency.
5.2.2.4 LFINTOSC
The Low-Frequency Internal Oscillator (LFINTOSC) is
an uncalibrated 31 kHz internal clock source.
The output of the LFINTOSC connects to a postscaler
and multiplexer (see Figure 5-1). Select 31 kHz, via
software, using the IRCF<3:0> bits of the OSCCON
register. See Section 5.2.2.7 “Internal Oscillator
Clock Switch Timing” for more information. The
LFINTOSC is also the frequency for the Power-up Timer
(PWRT), Watchdog Timer (WDT) and Fail-Safe Clock
Monitor (FSCM).
The LFINTOSC is enabled by selecting 31 kHz
(IRCF<3:0> bits of the OSCCON register = 000) as the
system clock source (SCS bits of the OSCCON
register = 1x), or when any of the following are
enabled:
• Configure the IRCF<3:0> bits of the OSCCON
register for the desired LF frequency, and
•FOSC<2:0> = 100, or
• Set the System Clock Source (SCS) bits of the
OSCCON register to ‘1x’
Peripherals that use the LFINTOSC are:
• Power-up Timer (PWRT)
• Watchdog Timer (WDT)
• Fail-Safe Clock Monitor (FSCM)
The Low Frequency Internal Oscillator Ready bit
(LFIOFR) of the OSCSTAT register indicates when the
LFINTOSC is running and can be utilized.
5.2.2.5 Internal Oscillator Frequency
Selection
The system clock speed can be selected via software
using the Internal Oscillator Frequency Select bits
IRCF<3:0> of the OSCCON register.
The output of the 16 MHz HFINTOSC and 31 kHz
LFINTOSC connects to a postscaler and multiplexer
(see Figure 5-1). The Internal Oscillator Frequency
Select bits IRCF<3:0> of the OSCCON register select
the frequency output of the internal oscillators. One of
the following frequencies can be selected via software:
• 32 MHz (requires 4X PLL)
•16 MHz
•8 MHz
•4 MHz
•2 MHz
•1 MHz
• 500 kHz (Default after Reset)
•250 kHz
•125 kHz
•62.5 kHz
•31.25 kHz
• 31 kHz (LFINTOSC)
The IRCF<3:0> bits of the OSCCON register allow
duplicate selections for some frequencies. These dupli-
cate choices can offer system design trade-offs. Lower
power consumption can be obtained when changing
oscillator sources for a given frequency. Faster transi-
tion times can be obtained between frequency changes
that use the same oscillator source.
Note: Following any Reset, the IRCF<3:0> bits of
the OSCCON register are set to ‘0111’ and
the frequency selection is set to 500 kHz.
The user can modify the IRCF bits to
select a different frequency.
2010 Microchip Technology Inc. Preliminary DS41413A-page 61
PIC12F/LF1822/16F/LF1823
5.2.2.6 32 MHz Internal Oscillator
Frequency Selection
The Internal Oscillator Block can be used with the 4X
PLL associated with the External Oscillator Block to
produce a 32 MHz internal system clock source. The
following settings are required to use the 32 MHz
internal clock source:
• The FOSC bits in Configuration Word 1 must be
set to use the INTOSC source as the device
system clock (FOSC<2:0> = 100).
• The IRCF bits in the OSCCON register must be
set to the 8 MHz HFINTOSC selection
(IRCF<3:0> = 1110).
• The SPLLEN bit in the OSCCON register must be
set to enable the 4xPLL, or the PLLEN bit of the
Configuration Word 2 must be programmed to a
‘1’.
The 4xPLL is not available for use with the internal
oscillator when the SCS bits of the OSCCON register
are set to ‘1x’. The SCS bits must be set to ‘00’ to use
the 4xPLL with the internal oscilator.
5.2.2.7 Internal Oscillator Clock Switch
Timing
When switching between the HFINTOSC, MFINTOSC
and the LFINTOSC, the new oscillator may already be
shut down to save power (see Figure 5-7). If this is the
case, there is a delay after the IRCF<3:0> bits of the
OSCCON register are modified before the frequency
selection takes place. The OSCSTAT register will
reflect the current active status of the HFINTOSC,
MFINTOSC and LFINTOSC oscillators. The sequence
of a frequency selection is as follows:
1. IRCF<3:0> bits of the OSCCON register are
modified.
2. If the new clock is shut down, a clock start-up
delay is started.
3. Clock switch circuitry waits for a falling edge of
the current clock.
4. The current clock is held low and the clock
switch circuitry waits for a rising edge in the new
clock.
5. The new clock is now active.
6. The OSCSTAT register is updated as required.
7. Clock switch is complete.
See Figure 5-7 for more details.
If the internal oscillator speed is switched between two
clocks of the same source, there is no start-up delay
before the new frequency is selected. Clock switching
time delays are shown in Table 5-1.
Start-up delay specifications are located in the
oscillator tables of Section 29.0 “Electrical
Specifications”.
Note: When using the PLLEN bit of the
Configuration Word 2, the 4xPLL cannot
be disabled by software and the 8 MHz
HFINTOSC option will no longer be
available.
PIC12F/LF1822/16F/LF1823
DS41413A-page 62 Preliminary 2010 Microchip Technology Inc.
FIGURE 5-7: INTERNAL OSCILLATOR SWITCH TIMING
HFINTOSC/
LFINTOSC
IRCF <3:0>
System Clock
HFINTOSC/
LFINTOSC
IRCF <3:0>
System Clock
00
00
Start-up Time 2-cycle Sync Running
2-cycle Sync Running
HFINTOSC/ LFINTOSC (FSCM and WDT disabled)
HFINTOSC/ LFINTOSC (Either FSCM or WDT enabled)
LFINTOSC
HFINTOSC/
IRCF <3:0>
System Clock
= 0 0
Start-up Time 2-cycle Sync Running
LFINTOSC HFINTOSC/MFINTOSC LFINTOSC turns off unless WDT or FSCM is enabled
MFINTOSC
MFINTOSC
MFINTOSC
MFINTOSC
MFINTOSC
2010 Microchip Technology Inc. Preliminary DS41413A-page 63
PIC12F/LF1822/16F/LF1823
5.3 Clock Switching
The system clock source can be switched between
external and internal clock sources via software using
the System Clock Select (SCS) bits of the OSCCON
register. The following clock sources can be selected
using the SCS bits:
• Default system oscillator determined by FOSC
bits in Configuration Word 1
• Timer1 32 kHz crystal oscillator
• Internal Oscillator Block (INTOSC)
5.3.1 SYSTEM CLOCK SELECT (SCS)
BITS
The System Clock Select (SCS) bits of the OSCCON
register selects the system clock source that is used for
the CPU and peripherals.
• When the SCS bits of the OSCCON register = 00,
the system clock source is determined by value of
the FOSC<2:0> bits in the Configuration Word 1.
• When the SCS bits of the OSCCON register = 01,
the system clock source is the Timer1 oscillator.
• When the SCS bits of the OSCCON register = 1x,
the system clock source is chosen by the internal
oscillator frequency selected by the IRCF<3:0>
bits of the OSCCON register. After a Reset, the
SCS bits of the OSCCON register are always
cleared.
When switching between clock sources, a delay is
required to allow the new clock to stabilize. These
oscillator delays are shown in Table 5-1.
5.3.2 OSCILLATOR START-UP TIME-OUT
STATUS (OSTS) BIT
The Oscillator Start-up Time-out Status (OSTS) bit of
the OSCSTAT register indicates whether the system
clock is running from the external clock source, as
defined by the FOSC<2:0> bits in the Configuration
Word 1, or from the internal clock source. In particular,
OSTS indicates that the Oscillator Start-up Timer
(OST) has timed out for LP, XT or HS modes. The OST
does not reflect the status of the Timer1 Oscillator.
5.3.3 TIMER1 OSCILLATOR
The Timer1 Oscillator is a separate crystal oscillator
associated with the Timer1 peripheral. It is optimized
for timekeeping operations with a 32.768 kHz crystal
connected between the T1OSO and T1OSI device
pins.
The Timer1 oscillator is enabled using the T1OSCEN
control bit in the T1CON register. See Section 20.0
“Timer1 Module with Gate Control” for more
information about the Timer1 peripheral.
5.3.4 TIMER1 OSCILLATOR READY
(T1OSCR) BIT
The user must ensure that the Timer1 Oscillator is
ready to be used before it is selected as a system clock
source. The Timer1 Oscillator Ready (T1OSCR) bit of
the OSCSTAT register indicates whether the Timer1
oscillator is ready to be used. After the T1OSCR bit is
set, the SCS bits can be configured to select the Timer1
oscillator.
Note: Any automatic clock switch, which may
occur from Two-Speed Start-up or Fail-Safe
Clock Monitor, does not update the SCS
bits of the OSCCON register. The user can
monitor the OSTS bit of the OSCSTAT
register to determine the current system
clock source.
PIC12F/LF1822/16F/LF1823
DS41413A-page 64 Preliminary 2010 Microchip Technology Inc.
5.4 Two-Speed Clock Start-up Mode
Two-Speed Start-up mode provides additional power
savings by minimizing the latency between external
oscillator start-up and code execution. In applications
that make heavy use of the Sleep mode, Two-Speed
Start-up will remove the external oscillator start-up
time from the time spent awake and can reduce the
overall power consumption of the device. This mode
allows the application to wake-up from Sleep, perform
a few instructions using the INTOSC internal oscillator
block as the clock source and go back to Sleep without
waiting for the external oscillator to become stable.
Two-Speed Start-up provides benefits when the oscil-
lator module is configured for LP, XT, or HS modes.
The Oscillator Start-up Timer (OST) is enabled for
these modes and must count 1024 oscillations before
the oscillator can be used as the system clock source.
If the oscillator module is configured for any mode
other than LP, XT or HS mode, then Two-Speed
Start-up is disabled. This is because the external clock
oscillator does not require any stabilization time after
POR or an exit from Sleep.
If the OST count reaches 1024 before the device
enters Sleep mode, the OSTS bit of the OSCSTAT reg-
ister is set and program execution switches to the
external oscillator. However, the system may never
operate from the external oscillator if the time spent
awake is very short.
5.4.1 TWO-SPEED START-UP MODE
CONFIGURATION
Two-Speed Start-up mode is configured by the
following settings:
• IESO (of the Configuration Word 1) = 1; Inter-
nal/External Switchover bit (Two-Speed Start-up
mode enabled).
• SCS (of the OSCCON register) = 00.
• FOSC<2:0> bits in the Configuration Word 1
configured for LP, XT or HS mode.
Two-Speed Start-up mode is entered after:
• Power-on Reset (POR) and, if enabled, after
Power-up Timer (PWRT) has expired, or
• Wake-up from Sleep.
TABLE 5-1: OSCILLATOR SWITCHING DELAYS
Note: Executing a SLEEP instruction will abort
the oscillator start-up time and will cause
the OSTS bit of the OSCSTAT register to
remain clear.
Switch From Switch To Frequency Oscillator Delay
Sleep/POR
LFINTOSC(1)
MFINTOSC(1)
HFINTOSC(1)
31 kHz
31.25 kHz-500 kHz
31.25kHz-16MHz
Oscillator Warm-up Delay (TWARM)
Sleep/POR EC, RC(1) DC – 32 MHz 2 cycles
LFINTOSC EC, RC(1) DC – 32 MHz 1 cycle of each
Sleep/POR Timer1 Oscillator
LP, XT, HS(1) 32 kHz-20 MHz 1024 Clock Cycles (OST)
Any clock source MFINTOSC(1)
HFINTOSC(1)
31.25 kHz-500 kHz
31.25kHz-16MHz 2s (approx.)
Any clock source LFINTOSC(1) 31 kHz 1 cycle of each
Any clock source Timer1 Oscillator 32 kHz 1024 Clock Cycles (OST)
PLL inactive PLL active 16-32 MHz 2 ms (approx.)
Note 1: PLL inactive.
2010 Microchip Technology Inc. Preliminary DS41413A-page 65
PIC12F/LF1822/16F/LF1823
5.4.2 TWO-SPEED START-UP
SEQUENCE
1. Wake-up from Power-on Reset or Sleep.
2. Instructions begin execution by the internal
oscillator at the frequency set in the IRCF<3:0>
bits of the OSCCON register.
3. OST enabled to count 1024 clock cycles.
4. OST timed out, wait for falling edge of the
internal oscillator.
5. OSTS is set.
6. System clock held low until the next falling edge
of new clock (LP, XT or HS mode).
7. System clock is switched to external clock
source.
5.4.3 CHECKING TWO-SPEED CLOCK
STATUS
Checking the state of the OSTS bit of the OSCSTAT
register will confirm if the microcontroller is running
from the external clock source, as defined by the
FOSC<2:0> bits in the Configuration Word 1, or the
internal oscillator.
FIGURE 5-8: TWO-SPEED START-UP
0 1 1022 1023
PC + 1
TOSTT
INTOSC
OSC1
OSC2
Program Counter
System Clock
PC - N PC
PIC12F/LF1822/16F/LF1823
DS41413A-page 66 Preliminary 2010 Microchip Technology Inc.
5.5 Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) allows the device
to continue operating should the external oscillator fail.
The FSCM can detect oscillator failure any time after
the Oscillator Start-up Timer (OST) has expired. The
FSCM is enabled by setting the FCMEN bit in the
Configuration Word 1. The FSCM is applicable to all
external Oscillator modes (LP, XT, HS, EC, Timer1
Oscillator and RC).
FIGURE 5-9: FSCM BLOCK DIAGRAM
5.5.1 FAIL-SAFE DETECTION
The FSCM module detects a failed oscillator by
comparing the external oscillator to the FSCM sample
clock. The sample clock is generated by dividing the
LFINTOSC by 64. See Figure 5-9. Inside the fail
detector block is a latch. The external clock sets the
latch on each falling edge of the external clock. The
sample clock clears the latch on each rising edge of the
sample clock. A failure is detected when an entire
half-cycle of the sample clock elapses before the
external clock goes low.
5.5.2 FAIL-SAFE OPERATION
When the external clock fails, the FSCM switches the
device clock to an internal clock source and sets the bit
flag OSFIF of the PIR2 register. Setting this flag will
generate an interrupt if the OSFIE bit of the PIE2
register is also set. The device firmware can then take
steps to mitigate the problems that may arise from a
failed clock. The system clock will continue to be
sourced from the internal clock source until the device
firmware successfully restarts the external oscillator
and switches back to external operation.
The internal clock source chosen by the FSCM is
determined by the IRCF<3:0> bits of the OSCCON
register. This allows the internal oscillator to be
configured before a failure occurs.
5.5.3 FAIL-SAFE CONDITION CLEARING
The Fail-Safe condition is cleared after a Reset,
executing a SLEEP instruction or changing the SCS bits
of the OSCCON register. When the SCS bits are
changed, the OST is restarted. While the OST is
running, the device continues to operate from the
INTOSC selected in OSCCON. When the OST times
out, the Fail-Safe condition is cleared and the device
will be operating from the external clock source. The
Fail-Safe condition must be cleared before the OSFIF
flag can be cleared.
5.5.4 RESET OR WAKE-UP FROM SLEEP
The FSCM is designed to detect an oscillator failure
after the Oscillator Start-up Timer (OST) has expired.
The OST is used after waking up from Sleep and after
any type of Reset. The OST is not used with the EC or
RC Clock modes so that the FSCM will be active as
soon as the Reset or wake-up has completed. When
the FSCM is enabled, the Two-Speed Start-up is also
enabled. Therefore, the device will always be executing
code while the OST is operating.
External
LFINTOSC ÷ 64
S
R
Q
31 kHz
(~32 s)
488 Hz
(~2 ms)
Clock Monitor
Latch
Clock
Failure
Detected
Oscillator
Clock
Q
Sample Clock
Note: Due to the wide range of oscillator start-up
times, the Fail-Safe circuit is not active
during oscillator start-up (i.e., after exiting
Reset or Sleep). After an appropriate
amount of time, the user should check the
Status bits in the OSCSTAT register to
verify the oscillator start-up and that the
system clock switchover has successfully
completed.
2010 Microchip Technology Inc. Preliminary DS41413A-page 67
PIC12F/LF1822/16F/LF1823
FIGURE 5-10: FSCM TIMING DIAGRAM
OSCFIF
System
Clock
Output
Sample Clock
Failure
Detected
Oscillator
Failure
Note: The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in
this example have been chosen for clarity.
(Q)
Te s t Test Test
Clock Monitor Output
PIC12F/LF1822/16F/LF1823
DS41413A-page 68 Preliminary 2010 Microchip Technology Inc.
5.6 Oscillator Control Registers
REGISTER 5-1: OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-1/1 R/W-1/1 R/W-1/1 U-0 R/W-0/0 R/W-0/0
SPLLEN IRCF<3:0> —SCS<1:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 SPLLEN: Software PLL Enable bit
If PLLEN in Configuration Word 1 = 1:
SPLLEN bit is ignored. 4x PLL is always enabled (subject to oscillator requirements)
If PLLEN in Configuration Word 1 = 0:
1 = 4x PLL Is enabled
0 = 4x PLL is disabled
bit 6-3 IRCF<3:0>: Internal Oscillator Frequency Select bits
000x =31kHz LF
0010 =31.25kHz MF
0011 =31.25kHz HF
(1)
0100 =62.5kHz MF
0101 =125kHz MF
0110 =250kHz MF
0111 = 500 kHz MF (default upon Reset)
1000 =125kHz HF
(1)
1001 =250kHz HF
(1)
1010 =500kHz HF
(1)
1011 =1MHz HF
1100 =2MHz HF
1101 =4MHz HF
1110 = 8 MHz or 32 MHz HF(see Section 5.2.2.1 “HFINTOSC”)
1111 = 16 MHz HF
bit 2 Unimplemented: Read as ‘0’
bit 1-0 SCS<1:0>: System Clock Select bits
1x = Internal oscillator block
01 = Timer1 oscillator
00 = Clock determined by FOSC<2:0> in Configuration Word 1
Note 1: Duplicate frequency derived from HFINTOSC.
2010 Microchip Technology Inc. Preliminary DS41413A-page 69
PIC12F/LF1822/16F/LF1823
REGISTER 5-2: OSCSTAT: OSCILLATOR STATUS REGISTER
R-1/q R-0/q R-q/q R-0/q R-0/q R-q/q R-0/0 R-0/q
T1OSCR PLLR OSTS HFIOFR HFIOFL MFIOFR LFIOFR HFIOFS
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared q = Conditional
bit 7 T1OSCR: Timer1 Oscillator Ready bit
If T1OSCEN = 1:
1 = Timer1 oscillator is ready
0 = Timer1 oscillator is not ready
If T1OSCEN = 0:
1 = Timer1 clock source is always ready
bit 6 PLLR 4x PLL Ready bit
1 = 4x PLL is ready
0 = 4x PLL is not ready
bit 5 OSTS: Oscillator Start-up Time-out Status bit
1 = Running from the clock defined by the FOSC<2:0> bits of the Configuration Word 1
0 = Running from an internal oscillator (FOSC<2:0> = 100)
bit 4 HFIOFR: High Frequency Internal Oscillator Ready bit
1 = HFINTOSC is ready
0 = HFINTOSC is not ready
bit 3 HFIOFL: High Frequency Internal Oscillator Locked bit
1 = HFINTOSC is at least 2% accurate
0 = HFINTOSC is not 2% accurate
bit 2 MFIOFR: Medium Frequency Internal Oscillator Ready bit
1 = MFINTOSC is ready
0 = MFINTOSC is not ready
bit 1 LFIOFR: Low Frequency Internal Oscillator Ready bit
1 = LFINTOSC is ready
0 = LFINTOSC is not ready
bit 0 HFIOFS: High Frequency Internal Oscillator Stable bit
1 = HFINTOSC is at least 0.5% accurate
0 = HFINTOSC is not 0.5% accurate
PIC12F/LF1822/16F/LF1823
DS41413A-page 70 Preliminary 2010 Microchip Technology Inc.
TABLE 5-2: SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES
TABLE 5-3: SUMMARY OF CONFIGURATION WORD WITH CLOCK SOURCES
REGISTER 5-3: OSCTUNE: OSCILLATOR TUNING REGISTER
U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
—— TUN<5:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 TUN<5:0>: Frequency Tuning bits
011111 = Maximum frequency
011110 =
•
•
•
000001 =
000000 = Oscillator module is running at the factory-calibrated frequency
111111 =
•
•
•
100000 = Minimum frequency
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
OSCCON SPLLEN IRCF<3:0> —SCS<1:0>68
OSCSTAT T1OSCR PLLR OSTS HFIOFR HFIOFL MFIOFR LFIOFR HFIOFS 69
OSCTUNE ——TUN<5:0>70
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE — — —91
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF — — — 93
T1CON TMR1CS<1:0> T1CKPS<1:0> T1OSCEN T1SYNC —TMR1ON 180
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by clock sources.
Note 1: PIC16F/LF1823 only.
Name Bits Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 Bit 10/2 Bit 9/1 Bit 8/0 Register
on Page
CONFIG1 13:8 — — FCMEN IESO CLKOUTEN BOREN<1:0> CPD 50
7:0 CP MCLRE PWRTE WDTE<1:0> FOSC<2:0>
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by clock sources.
Note 1: PIC12F1822/16F1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 71
PIC12F/LF1822/16F/LF1823
6.0 REFERENCE CLOCK MODULE
The reference clock module provides the ability to send
a divided clock to the clock output pin of the device
(CLKR) and provide a secondary internal clock source
to the modulator module. This module is available in all
oscillator configurations and allows the user to select a
greater range of clock submultiples to drive external
devices in the application. The reference clock module
includes the following features:
• System clock is the source
• Available in all oscillator configurations
• Programmable clock divider
• Output enable to a port pin
• Selectable duty cycle
• Slew rate control
The reference clock module is controlled by the CLKR-
CON register (Register 6-1) and is enabled when set-
ting the CLKREN bit. To output the divided clock signal
to the CLKR port pin, the CLKROE bit must be set. The
CLKRDIV<2:0> bits enable the selection of 8 different
clock divider options. The CLKRDC<1:0> bits can be
used to modify the duty cycle of the output clock(1). The
CLKRSLR bit controls slew rate limiting.
For information on using the reference clock output
with the modulator module, see Section 22.0 “Data
Signal Modulator”.
6.1 Slew rate
The slew rate limitation on the output port pin can be
disabled. The Slew Rate limitation can be removed by
clearing the CLKRSLR bit in the CLKRCON register.
6.2 Effects of a Reset
Upon any device Reset, the reference clock module is
disabled. The user’s firmware is responsible for
initializing the module before enabling the output. The
registers are reset to their default values.
6.3 Conflicts with the CLKR pin
There are two cases when the reference clock output
signal cannot be output to the CLKR pin, if:
• LP, XT, or HS oscillator mode is selected.
• CLKOUT function is enabled.
Even if either of these cases are true, the module can
still be enabled and the reference clock signal may be
used in conjunction with the modulator module.
6.3.1 OSCILLATOR MODES
If LP, XT, or HS oscillator modes are selected, the
OSC2/CLKR pin must be used as an oscillator input pin
and the CLKR output cannot be enabled. See
Section 5.2 “Clock Source Types” for more informa-
tion on different oscillator modes.
6.3.2 CLKOUT FUNCTION
The CLKOUT function has a higher priority than the
reference clock module. Therefore, if the CLKOUT
function is enabled by the CLKOUTEN bit in Configura-
tion Word 1, FOSC/4 will always be output on the port
pin. Reference Section 4.0 “Device Configuration”
for more information.
6.4 Operation During Sleep
As the reference clock module relies on the system
clock as its source, and the system clock is disabled in
Sleep, the module does not function in Sleep, even if
an external clock source or the Timer1 clock source is
configured as the system clock. The module outputs
will remain in their current state until the device exits
Sleep.
Note 1: If the base clock rate is selected without a
divider, the output clock will always have
a duty cycle equal to that of the source
clock, unless a 0% duty cycle is selected.
If the clock divider is set to base clock/2,
then 25% and 75% duty cycle accuracy
will be dependent upon the source clock.
PIC12F/LF1822/16F/LF1823
DS41413A-page 72 Preliminary 2010 Microchip Technology Inc.
REGISTER 6-1: CLKRCON: REFERENCE CLOCK CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-1/1 R/W-1/1 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
CLKREN CLKROE CLKRSLR CLKRDC1 CLKRDC0 CLKRDIV2 CLKRDIV1 CLKRDIV0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 CLKREN: Reference Clock Module Enable bit
1 = Reference clock module is enabled
0 = Reference clock module is disabled
bit 6 CLKROE: Reference Clock Output Enable bit(3)
1 = Reference clock output is enabled on CLKR pin
0 = Reference clock output disabled on CLKR pin
bit 5 CLKRSLR: Reference Clock Slew Rate Control limiting enable bit
1 = Slew rate limiting is enabled
0 = Slew rate limiting is disabled
bit 4-3 CLKRDC<1:0>: Reference Clock Duty Cycle bits
11 = Clock outputs duty cycle of 75%
10 = Clock outputs duty cycle of 50%
01 = Clock outputs duty cycle of 25%
00 = Clock outputs duty cycle of 0%
bit 2-0 CLKRDIV<2:0> Reference Clock Divider bits
111 = Base clock value divided by 128
110 = Base clock value divided by 64
101 = Base clock value divided by 32
100 = Base clock value divided by 16
011 = Base clock value divided by 8
010 = Base clock value divided by 4
001 = Base clock value divided by 2(1)
000 = Base clock value(2)
Note 1: In this mode, the 25% and 75% duty cycle accuracy will be dependent on the source clock duty cycle.
2: In this mode, the duty cycle will always be equal to the source clock duty cycle, unless a duty cycle of 0%
is selected.
3: To route CLKR to pin, CLKOUTEN of Configuration Word 1 = 1 is required. CLKOUTEN of Configuration
Word 1 = 0 will result in FOSC/4. See Section 6.3 “Conflicts with the CLKR pin” for details.
2010 Microchip Technology Inc. Preliminary DS41413A-page 73
PIC12F/LF1822/16F/LF1823
TABLE 6-1: SUMMARY OF REGISTERS ASSOCIATED WITH REFERENCE CLOCK SOURCES
TABLE 6-2: SUMMARY OF CONFIGURATION WORD WITH REFERENCE CLOCK SOURCES
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CLKRCON CLKREN CLKROE CLKRSLR CLKRDC1 CLKRDC0
CLKRDIV2 CLKRDIV1 CLKRDIV0
72
Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used by reference clock sources.
Name Bits Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 Bit 10/2 Bit 9/1 Bit 8/0 Register
on Page
CONFIG1 13:8 — — FCMEN IESO CLKOUTEN BOREN1 BOREN0 CPD 50
7:0 CP MCLRE PWRTE WDTE1 WDTE0 FOSC2 FOSC1 FOSC0
Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used by reference clock sources.
PIC12F/LF1822/16F/LF1823
DS41413A-page 74 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 75
PIC12F/LF1822/16F/LF1823
7.0 RESETS
There are multiple ways to reset this device:
• Power-on Reset (POR)
• Brown-out Reset (BOR)
•MCLR
Reset
•WDT Reset
•RESET instruction
• Stack Overflow
• Stack Underflow
• Programming mode exit
To allo w V DD to stabilize, an optional power-up timer
can be enabled to extend the Reset time after a BOR
or POR event.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 7-1.
FIGURE 7-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
External Reset
MCLR
VDD
WDT
Time-out
Power-on
Reset
LFINTOSC
PWRT
64 ms
PWRTEN
Brown-out
Reset
BOR
RESET Instruction
Stack
Pointer
Stack Overflow/Underflow Reset
Sleep
MCLRE
Enable
Device
Reset
Zero
Programming Mode Exit
PIC12F/LF1822/16F/LF1823
DS41413A-page 76 Preliminary 2010 Microchip Technology Inc.
7.1 Power-on Reset (POR)
The POR circuit holds the device in Reset until VDD has
reached an acceptable level for minimum operation.
Slow rising VDD, fast operating speeds or analog
performance may require greater than minimum VDD.
The PWRT, BOR or MCLR features can be used to
extend the start-up period until all device operation
conditions have been met.
7.1.1 POWER-UP TIMER (PWRT)
The Power-up Timer provides a nominal 64 ms time-
out on POR or Brown-out Reset.
The device is held in Reset as long as PWRT is active.
The PWRT delay allows additional time for the VDD to
rise to an acceptable level. The Power-up Timer is
enabled by clearing the PWRTE bit in Configuration
Word 1.
The Power-up Timer starts after the release of the POR
and BOR.
For additional information, refer to Application Note
AN607, “Power-up Trouble Shooting” (DS00607).
7.2 Brown-Out Reset (BOR)
The BOR circuit holds the device in Reset when VDD
reaches a selectable minimum level. Between the
POR and BOR, complete voltage range coverage for
execution protection can be implemented.
The Brown-out Reset module has four operating
modes controlled by the BOREN<1:0> bits in Configu-
ration Word 1. The four operating modes are:
• BOR is always on
• BOR is off when in Sleep
• BOR is controlled by software
• BOR is always off
Refer to Table 7-3 for more information.
The Brown-out Reset voltage level is selectable by
configuring the BORV bit in Configuration Word 2.
A VDD noise rejection filter prevents the BOR from trig-
gering on small events. If VDD falls below VBOR for a
duration greater than parameter TBORDC, the device
will reset. See Figure 7-3 for more information.
TABLE 7-1: BOR OPERATING MODES
7.2.1 BOR IS ALWAYS ON
When the BOREN bits of Configuration Word 1 are set
to ‘11’, the BOR is always on. The device start-up will
be delayed until the BOR is ready and VDD is higher
than the BOR threshold.
BOR protection is active during Sleep. The BOR does
not delay wake-up from Sleep.
7.2.2 BOR IS OFF IN SLEEP
When the BOREN bits of Configuration Word 1 are set
to ‘10’, the BOR is on, except in Sleep. The device
start-up will be delayed until the BOR is ready and VDD
is higher than the BOR threshold.
BOR protection is not active during Sleep. The device
wake-up will be delayed until the BOR is ready.
7.2.3 BOR CONTROLLED BY SOFTWARE
When the BOREN bits of Configuration Word 1 are set
to ‘01’, the BOR is controlled by the SBOREN bit of the
BORCON register. The device start-up is not delayed
by the BOR ready condition or the VDD level.
BOR protection begins as soon as the BOR circuit is
ready. The status of the BOR circuit is reflected in the
BORRDY bit of the BORCON register.
BOR protection is unchanged by Sleep.
BOREN
Config bits SBOREN Device Mode BOR Mode
Device
Operation upon
release of POR
Device
Operation upon
wake- up from
Sleep
BOR_ON (11)XX Active Waits for BOR ready(1)
BOR_NSLEEP (10) X Awake Active Waits for BOR ready
BOR_NSLEEP (10)XSleep Disabled
BOR_SBOREN (01)1X Active Begins immediately
BOR_SBOREN (01)0X Disabled Begins immediately
BOR_OFF (00)XX Disabled Begins immediately
Note 1: Even though this case specifically waits for the BOR, the BOR is already operating, so there is no delay in
start-up.
2010 Microchip Technology Inc. Preliminary DS41413A-page 77
PIC12F/LF1822/16F/LF1823
FIGURE 7-2: BROWN-OUT READY
FIGURE 7-3: BROWN-OUT SITUATIONS
REGISTER 7-1: BORCON: BROWN-OUT RESET CONTROL REGISTER
R/W-1/u U-0 U-0 U-0 U-0 U-0 U-0 R-q/u
SBOREN — — — — — —BORRDY
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition
bit 7 SBOREN: Software Brown-out Reset Enable bit
If BOREN <1:0> in Configuration Word 1 01:
SBOREN is read/write, but has no effect on the BOR.
If BOREN <1:0> in Configuration Word 1 = 01:
1 = BOR Enabled
0 = BOR Disabled
bit 6-1 Unimplemented: Read as ‘0’
bit 0 BORRDY: Brown-out Reset Circuit Ready Status bit
1 = The Brown-out Reset circuit is active
0 = The Brown-out Reset circuit is inactive
TBORRDY
SBOREN
BORRDY BOR Protection Active
TPWRT(1)
VBOR
VDD
Internal
Reset
VBOR
VDD
Internal
Reset TPWRT(1)
< TPWRT
TPWRT(1)
VBOR
VDD
Internal
Reset
Note 1: TPWRT delay only if PWRTE bit is programmed to ‘0’.
PIC12F/LF1822/16F/LF1823
DS41413A-page 78 Preliminary 2010 Microchip Technology Inc.
7.3 MCLR
The MCLR is an optional external input that can reset
the device. The MCLR function is controlled by the
MCLRE bit of Configuration Word 1 and the LVP bit of
Configuration Word 2 (Table 7-2).
7.3.1 MCLR ENABLED
When MCLR is enabled and the pin is held low, the
device is held in Reset. The MCLR pin is connected to
VDD through an internal weak pull-up.
The device has a noise filter in the MCLR Reset path.
The filter will detect and ignore small pulses.
7.3.2 MCLR DISABLED
When MCLR is disabled, the pin functions as a general
purpose input and the internal weak pull-up is under
software control. See Section 12.2 “PORTA Registers”
for more information.
7.4 Watchdog Timer (WDT) Reset
The Watchdog Timer generates a Reset if the firmware
does not issue a CLRWDT instruction within the time-out
period. The TO and PD bits in the STATUS register are
changed to indicate the WDT Reset. See Section 10.0
“Watchdog Timer” for more information.
7.5 RESET Instruction
A RESET instruction will cause a device Reset. The RI
bit in the PCON register will be set to ‘0’. See Table 7-4
for default conditions after a RESET instruction has
occurred.
7.6 Stack Overflow/Underflow Reset
The device can reset when the Stack Overflows or
Underflows. The STKOVF or STKUNF bits of the PCON
register indicate the Reset condition. These Resets are
enabled by setting the STVREN bit in Configuration
Word 2. See Section 3.4.2 “Overflow/Underflow
Reset” for more information.
7.7 Programming Mode Exit
Upon exit of Programming mode, the device will
behave as if a POR had just occurred.
7.8 Power-Up Timer
The Power-up Timer optionally delays device execution
after a BOR or POR event. This timer is typically used to
allow VDD to stabilize before allowing the device to start
running.
The Power-up Timer is controlled by the PWRTE bit of
Configuration Word 1.
7.9 Start-up Sequence
Upon the release of a POR or BOR, the following must
occur before the device will begin executing:
1. Power-up Timer runs to completion (if enabled).
2. Oscillator start-up timer runs to completion (if
required for oscillator source).
3. MCLR must be released (if enabled).
The total time-out will vary based on oscillator configu-
ration and Power-up Timer configuration. See
Section 5.0 “Oscillator Module (With Fail-Safe
Clock Monitor)” for more information.
The Power-up Timer and oscillator start-up timer run
independently of MCLR Reset. If MCLR is kept low long
enough, the Power-up Timer and oscillator start-up
timer will expire. Upon bringing MCLR high, the device
will begin execution immediately (see Figure 7-4). This
is useful for testing purposes or to synchronize more
than one device operating in parallel.
TABLE 7-2: MCLR CONFIGURATION
MCLRE LVP MCLR
00Disabled
10Enabled
x1Enabled
Note: A Reset does not drive the MCLR pin low.
2010 Microchip Technology Inc. Preliminary DS41413A-page 79
PIC12F/LF1822/16F/LF1823
FIGURE 7-4: RESET START-UP SEQUENCE
TOST
TMCLR
TPWRT
VDD
Internal POR
Power-Up Timer
MCLR
Internal RESET
Oscillator Modes
Oscillator Start-Up Timer
Oscillator
FOSC
Internal Oscillator
Oscillator
FOSC
External Clock (EC)
CLKIN
FOSC
External Crystal
PIC12F/LF1822/16F/LF1823
DS41413A-page 80 Preliminary 2010 Microchip Technology Inc.
7.10 Determining the Cause of a Reset
Upon any Reset, multiple bits in the STATUS and
PCON register are updated to indicate the cause of the
Reset. Table 7-3 and Table 7-4 show the Reset condi-
tions of these registers.
TABLE 7-3: RESET STATUS BITS AND THEIR SIGNIFICANCE
TABLE 7-4: RESET CONDITION FOR SPECIAL REGISTERS(2)
STKOVF STKUNF RMCLR RI POR BOR TO PD Condition
00110x11Power-on Reset
00110x0xIllegal, TO is set on POR
00110xx0Illegal, PD is set on POR
0011u011Brown-out Reset
uuuuuu0uWDT Reset
uuuuuu00WDT Wake-up from Sleep
uuuuuu10Interrupt Wake-up from Sleep
uu0uuuuuMCLR Reset during normal operation
uu0uuu10MCLR Reset during Sleep
u u u 0 u u u u RESET Instruction Executed
1uuuuuuuStack Overflow Reset (STVREN = 1)
u1uuuuuuStack Underflow Reset (STVREN = 1)
Condition Program
Counter
STATUS
Register
PCON
Register
Power-on Reset 0000h ---1 1000 00-- 110x
MCLR Reset during normal operation 0000h ---u uuuu uu-- 0uuu
MCLR Reset during Sleep 0000h ---1 0uuu uu-- 0uuu
WDT Reset 0000h ---0 uuuu uu-- uuuu
WDT Wake-up from Sleep PC + 1 ---0 0uuu uu-- uuuu
Brown-out Reset 0000h ---1 1uuu 00-- 11u0
Interrupt Wake-up from Sleep PC + 1(1) ---1 0uuu uu-- uuuu
RESET Instruction Executed 0000h ---u uuuu uu-- u0uu
Stack Overflow Reset (STVREN = 1) 0000h ---u uuuu 1u-- uuuu
Stack Underflow Reset (STVREN = 1) 0000h ---u uuuu u1-- uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, reads as ‘0’.
Note 1: When the wake-up is due to an interrupt and Global Enable bit (GIE) is set, the return address is pushed on
the stack and PC is loaded with the interrupt vector (0004h) after execution of PC + 1.
2: If a Status bit is not implemented, that bit will be read as ‘0’.
2010 Microchip Technology Inc. Preliminary DS41413A-page 81
PIC12F/LF1822/16F/LF1823
7.11 Power Control (PCON) Register
The Power Control (PCON) register contains flag bits
to differentiate between a:
• Power-on Reset (POR)
• Brown-out Reset (BOR)
• Reset Instruction Reset (RI)
• Stack Overflow Reset (STKOVF)
• Stack Underflow Reset (STKUNF)
•MCLR
Reset (RMCLR)
The PCON register bits are shown in Register 7-2.
REGISTER 7-2: PCON: POWER CONTROL REGISTER
R/W/HS-0/q R/W/HS-0/q U-0 U-0 R/W/HC-1/q R/W/HC-1/q R/W/HC-q/u R/W/HC-q/u
STKOVF STKUNF — — RMCLR RI POR BOR
bit 7 bit 0
Legend:
HC = Bit is cleared by hardware HS = Bit is set by hardware
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -m/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition
bit 7 STKOVF: Stack Overflow Flag bit
1 = A Stack Overflow occurred
0 = A Stack Overflow has not occurred or set to ‘0’ by firmware
bit 6 STKUNF: Stack Underflow Flag bit
1 = A Stack Underflow occurred
0 = A Stack Underflow has not occurred or set to ‘0’ by firmware
bit 5-4 Unimplemented: Read as ‘0’
bit 3 RMCLR: MCLR Reset Flag bit
1 = A MCLR Reset has not occurred or set to ‘1’ by firmware
0 = A MCLR Reset has occurred (set to ‘0’ in hardware when a MCLR Reset occurs)
bit 2 RI: RESET Instruction Flag bit
1 = A RESET instruction has not been executed or set to ‘1’ by firmware
0 = A RESET instruction has been executed (set to ‘0’ in hardware upon executing a RESET instruction)
bit 1 POR: Power-on Reset Status bit
1 = No Power-on Reset occurred
0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)
bit 0 BOR: Brown-out Reset Status bit
1 = No Brown-out Reset occurred
0 = A Brown-out Reset occurred (must be set in software after a Power-on Reset or Brown-out Reset
occurs)
PIC12F/LF1822/16F/LF1823
DS41413A-page 82 Preliminary 2010 Microchip Technology Inc.
TABLE 7-5: SUMMARY OF REGISTERS ASSOCIATED WITH RESETS
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BORCON SBOREN —————— BORRDY 77
PCON STKOVF STKUNF ——RMCLRRI POR BOR 81
STATUS — — —TOPD ZDC C24
WDTCON —— WDTPS4 WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN 101
Legend: — = unimplemented bit, reads as ‘0’. Shaded cells are not used by Resets.
Note 1: Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation.
2010 Microchip Technology Inc. Preliminary DS41413A-page 83
PIC12F/LF1822/16F/LF1823
8.0 INTERRUPTS
The interrupt feature allows certain events to preempt
normal program flow. Firmware is used to determine
the source of the interrupt and act accordingly. Some
interrupts can be configured to wake the MCU from
Sleep mode.
This chapter contains the following information for
Interrupts:
• Operation
• Interrupt Latency
• Interrupts During Sleep
•INT Pin
• Automatic Context Saving
Many peripherals produce Interrupts. Refer to the
corresponding chapters for details.
A block diagram of the interrupt logic is shown in
Figure 8-1 and Figure 8-2.
FIGURE 8-1: INTERRUPT LOGIC
TMR0IF
TMR0IE
INTF
INTE
IOCIF
IOCIE
GIE
PEIE
Wake-up (If in Sleep mode)
Interrupt to CPU
From Peripheral Interrupt
Logic (Figure 8-2)
PIC12F/LF1822/16F/LF1823
DS41413A-page 84 Preliminary 2010 Microchip Technology Inc.
FIGURE 8-2: PERIPHERAL INTERRUPT LOGIC
CCP1IF
CCP1IE
TMR1IF
TMR1IE
TMR2IF
TMR2IE
EEIF
EEIE
OSFIF
OSFIE
C1IF
C1IE
C2IF(1)
C2IE(1)
BCLIF
BCLIE
TMR1GIF
TMR1GIE
ADIF
ADIE
RCIF
RCIE
TXIF
TXIE
SSPIF
SSPIE
To Interrupt Logic
(Figure 8-1)
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 85
PIC12F/LF1822/16F/LF1823
8.1 Operation
Interrupts are disabled upon any device Reset. They
are enabled by setting the following bits:
• GIE bit of the INTCON register
• Interrupt Enable bit(s) for the specific interrupt
event(s)
• PEIE bit of the INTCON register (if the Interrupt
Enable bit of the interrupt event is contained in the
PIEx register)
The INTCON, PIR1, and PIR2 registers record individual
interrupts via interrupt flag bits. Interrupt flag bits will be
set, regardless of the status of the GIE, PEIE and
individual interrupt enable bits.
The following events happen when an interrupt event
occurs while the GIE bit is set:
• Current prefetched instruction is flushed
• GIE bit is cleared
• Current Program Counter (PC) is pushed onto the
stack
• Critical registers are automatically saved to the
shadow registers (See Section 8.5 “Automatic
Context Saving”)
• PC is loaded with the interrupt vector 0004h
The firmware within the Interrupt Service Routine (ISR)
should determine the source of the interrupt by polling
the interrupt flag bits. The interrupt flag bits must be
cleared before exiting the ISR to avoid repeated
interrupts. Because the GIE bit is cleared, any interrupt
that occurs while executing the ISR will be recorded
through its interrupt flag, but will not cause the
processor to redirect to the interrupt vector.
The RETFIE instruction exits the ISR by popping the
previous address from the stack, restoring the saved
context from the shadow registers and setting the GIE
bit.
For additional information on a specific interrupt’s
operation, refer to its peripheral chapter.
8.2 Interrupt Latency
Interrupt latency is defined as the time from when the
interrupt event occurs to the time code execution at the
interrupt vector begins. The latency for synchronous
interrupts is 3 or 4 instruction cycles. For asynchronous
interrupts, the latency is 3 to 5 instruction cycles,
depending on when the interrupt occurs. See Figure 8-3
and Figure 8-4 for more details.
Note 1: Individual interrupt flag bits are set,
regardless of the state of any other
enable bits.
2: All interrupts will be ignored while the GIE
bit is cleared. Any interrupt occurring
while the GIE bit is clear will be serviced
when the GIE bit is set again.
PIC12F/LF1822/16F/LF1823
DS41413A-page 86 Preliminary 2010 Microchip Technology Inc.
FIGURE 8-3: INTERRUPT LATENCY
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
CLKOUT
PC 0004h 0005h
PC
Inst(0004h)NOP
GIE
Q1 Q2 Q3 Q4Q1 Q2 Q3 Q4
1 Cycle Instruction at PC
PC
Inst(0004h)NOP
2 Cycle Instruction at PC
FSR ADDR PC+1 PC+2 0004h 0005h
PC
Inst(0004h)NOP
GIE
PCPC-1
3 Cycle Instruction at PC
Execute
Interrupt
Inst(PC)
Interrupt Sampled
during Q1
Inst(PC)
PC-1 PC+1
NOP
PC New PC/
PC+1 0005hPC-1 PC+1/FSR
ADDR 0004h
NOP
Interrupt
GIE
Interrupt
INST(PC) NOPNOP
FSR ADDR PC+1 PC+2 0004h 0005h
PC
Inst(0004h)NOP
GIE
PCPC-1
3 Cycle Instruction at PC
Interrupt
INST(PC) NOPNOP NOP
Inst(0005h)
Execute
Execute
Execute
2010 Microchip Technology Inc. Preliminary DS41413A-page 87
PIC12F/LF1822/16F/LF1823
FIGURE 8-4: INT PIN INTERRUPT TIMING
Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4 Q2Q1 Q3 Q4
OSC1
CLKOUT
INT pin
INTF
GIE
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
Interrupt Latency
PC PC + 1 PC + 1 0004h 0005h
Inst (0004h) Inst (0005h)
Dummy Cycle
Inst (PC) Inst (PC + 1)
Inst (PC – 1) Inst (0004h)
Dummy Cycle
Inst (PC)
—
Note 1: INTF flag is sampled here (every Q1).
2: Asynchronous interrupt latency = 3-5 TCY. Synchronous latency = 3-4 TCY, where TCY = instruction cycle time.
Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction.
3: CLKOUT not available in all oscillator modes.
4: For minimum width of INT pulse, refer to AC specifications in Section 29.0 “Electrical Specifications”.
5: INTF is enabled to be set any time during the Q4-Q1 cycles.
(1)
(2)
(3)
(4)
(5)
(1)
PIC12F/LF1822/16F/LF1823
DS41413A-page 88 Preliminary 2010 Microchip Technology Inc.
8.3 Interrupts During Sleep
Some interrupts can be used to wake from Sleep. To
wake from Sleep, the peripheral must be able to
operate without the system clock. The interrupt source
must have the appropriate Interrupt Enable bit(s) set
prior to entering Sleep.
On waking from Sleep, if the GIE bit is also set, the
processor will branch to the interrupt vector. Otherwise,
the processor will continue executing instructions after
the SLEEP instruction. The instruction directly after the
SLEEP instruction will always be executed before
branching to the ISR. Refer to the Section 9.0 “Power-
Down Mode (Sleep)” for more details.
8.4 INT Pin
The INT pin can be used to generate an asynchronous
edge-triggered interrupt. This interrupt is enabled by
setting the INTE bit of the INTCON register. The
INTEDG bit of the OPTION register determines on which
edge the interrupt will occur. When the INTEDG bit is
set, the rising edge will cause the interrupt. When the
INTEDG bit is clear, the falling edge will cause the
interrupt. The INTF bit of the INTCON register will be set
when a valid edge appears on the INT pin. If the GIE and
INTE bits are also set, the processor will redirect
program execution to the interrupt vector.
8.5 Automatic Context Saving
Upon entering an interrupt, the return PC address is
saved on the stack. Additionally, the following registers
are automatically saved in the Shadow registers:
• W register
• STATUS register (except for TO and PD)
• BSR register
• FSR registers
• PCLATH register
Upon exiting the Interrupt Service Routine, these regis-
ters are automatically restored. Any modifications to
these registers during the ISR will be lost. If modifica-
tions to any of these registers are desired, the corre-
sponding Shadow register should be modified and the
value will be restored when exiting the ISR. The
Shadow registers are available in Bank 31 and are
readable and writable. Depending on the user’s appli-
cation, other registers may also need to be saved.
2010 Microchip Technology Inc. Preliminary DS41413A-page 89
PIC12F/LF1822/16F/LF1823
8.5.1 INTCON REGISTER
The INTCON register is a readable and writable
register, which contains the various enable and flag bits
for TMR0 register overflow, interrupt-on-change and
external INT pin interrupts.
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the Global
Enable bit, GIE, of the INTCON register.
User software should ensure the appropri-
ate interrupt flag bits are clear prior to
enabling an interrupt.
REGISTER 8-1: INTCON: INTERRUPT CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R-0/0
GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 GIE: Global Interrupt Enable bit
1 = Enables all active interrupts
0 = Disables all interrupts
bit 6 PEIE: Peripheral Interrupt Enable bit
1 = Enables all active peripheral interrupts
0 = Disables all peripheral interrupts
bit 5 TMR0IE: Timer0 Overflow Interrupt Enable bit
1 = Enables the Timer0 interrupt
0 = Disables the Timer0 interrupt
bit 4 INTE: INT External Interrupt Enable bit
1 = Enables the INT external interrupt
0 = Disables the INT external interrupt
bit 3 IOCIE: Interrupt-on-Change Enable bit
1 = Enables the interrupt-on-change
0 = Disables the interrupt-on-change
bit 2 TMR0IF: Timer0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed
0 = TMR0 register did not overflow
bit 1 INTF: INT External Interrupt Flag bit
1 = The INT external interrupt occurred
0 = The INT external interrupt did not occur
bit 0 IOCIF: Interrupt-on-Change Interrupt Flag bit
1 = When at least one of the interrupt-on-change pins changed state
0 = None of the interrupt-on-change pins have changed state
PIC12F/LF1822/16F/LF1823
DS41413A-page 90 Preliminary 2010 Microchip Technology Inc.
8.5.2 PIE1 REGISTER
The PIE1 register contains the interrupt enable bits, as
shown in Register 8-2.
Note: Bit PEIE of the INTCON register must be
set to enable any peripheral interrupt.
REGISTER 8-2: PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 TMR1GIE: Timer1 Gate Interrupt Enable bit
1 = Enables the Timer1 Gate Acquisition interrupt
0 = Disables the Timer1 Gate Acquisition interrupt
bit 6 ADIE: A/D Converter (ADC) Interrupt Enable bit
1 = Enables the ADC interrupt
0 = Disables the ADC interrupt
bit 5 RCIE: USART Receive Interrupt Enable bit
1 = Enables the USART receive interrupt
0 = Disables the USART receive interrupt
bit 4 TXIE: USART Transmit Interrupt Enable bit
1 = Enables the USART transmit interrupt
0 = Disables the USART transmit interrupt
bit 3 SSP1IE: Synchronous Serial Port (MSSP) Interrupt Enable bit
1 = Enables the MSSP interrupt
0 = Disables the MSSP interrupt
bit 2 CCP1IE: CCP1 Interrupt Enable bit
1 = Enables the CCP1 interrupt
0 = Disables the CCP1 interrupt
bit 1 TMR2IE: TMR2 to PR2 Match Interrupt Enable bit
1 = Enables the Timer2 to PR2 match interrupt
0 = Disables the Timer2 to PR2 match interrupt
bit 0 TMR1IE: Timer1 Overflow Interrupt Enable bit
1 = Enables the Timer1 overflow interrupt
0 = Disables the Timer1 overflow interrupt
2010 Microchip Technology Inc. Preliminary DS41413A-page 91
PIC12F/LF1822/16F/LF1823
8.5.3 PIE2 REGISTER
The PIE2 register contains the interrupt enable bits, as
shown in Register 8-3.
Note: Bit PEIE of the INTCON register must be
set to enable any peripheral interrupt.
REGISTER 8-3: PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 U-0 U-0
OSFIE C2IE(1) C1IE EEIE BCL1IE — — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 OSFIE: Oscillator Fail Interrupt Enable bit
1 = Enables the Oscillator Fail interrupt
0 = Disables the Oscillator Fail interrupt
bit 6 C2IE: Comparator C2 Interrupt Enable bit(1)
1 = Enables the Comparator C2 interrupt
0 = Disables the Comparator C2 interrupt
bit 5 C1IE: Comparator C1 Interrupt Enable bit
1 = Enables the Comparator C1 interrupt
0 = Disables the Comparator C1 interrupt
bit 4 EEIE: EEPROM Write Completion Interrupt Enable bit
1 = Enables the EEPROM Write Completion interrupt
0 = Disables the EEPROM Write Completion interrupt
bit 3 BCL1IE: MSSP Bus Collision Interrupt Enable bit
1 = Enables the MSSP Bus Collision Interrupt
0 = Disables the MSSP Bus Collision Interrupt
bit 2-0 Unimplemented: Read as ‘0’
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 92 Preliminary 2010 Microchip Technology Inc.
8.5.4 PIR1 REGISTER
The PIR1 register contains the interrupt flag bits, as
shown in Register 8-4.
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the Global
Enable bit, GIE, of the INTCON register.
User software should ensure the
appropriate interrupt flag bits are clear prior
to enabling an interrupt.
REGISTER 8-4: PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1
R/W-0/0 R/W-0/0 R-0/0 R-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 TMR1GIF: Timer1 Gate Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 6 ADIF: A/D Converter Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 5 RCIF: USART Receive Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 4 TXIF: USART Transmit Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 3 SSP1IF: Synchronous Serial Port (MSSP) Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 2 CCP1IF: CCP1 Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 1 TMR2IF: Timer2 to PR2 Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 0 TMR1IF: Timer1 Overflow Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
2010 Microchip Technology Inc. Preliminary DS41413A-page 93
PIC12F/LF1822/16F/LF1823
8.5.5 PIR2 REGISTER
The PIR2 register contains the interrupt flag bits, as
shown in Register 8-5.
Note: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the Global
Enable bit, GIE, of the INTCON register.
User software should ensure the
appropriate interrupt flag bits are clear prior
to enabling an interrupt.
REGISTER 8-5: PIR2: PERIPHERAL INTERRUPT REQUEST REGISTER 2
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 U-0 U-0
OSFIF C2IF(1) C1IF EEIF BCL1IF — — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 OSFIF: Oscillator Fail Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 6 C2IF: Comparator C2 Interrupt Flag bit(1)
1 = Interrupt is pending
0 = Interrupt is not pending
bit 5 C1IF: Comparator C1 Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 4 EEIF: EEPROM Write Completion Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 3 BCL1IF: MSSP Bus Collision Interrupt Flag bit
1 = Interrupt is pending
0 = Interrupt is not pending
bit 2-0 Unimplemented: Read as ‘0’
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 94 Preliminary 2010 Microchip Technology Inc.
TABLE 8-1: SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPTS
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
OPTION_REG WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 171
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE — — — 91
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF — — — 93
Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used by Interrupts.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 95
PIC12F/LF1822/16F/LF1823
9.0 POWER-DOWN MODE (SLEEP)
The Power-Down mode is entered by executing a
SLEEP instruction.
Upon entering Sleep mode, the following conditions
exist:
1. WDT will be cleared but keeps running, if
enabled for operation during Sleep.
2. PD bit of the STATUS register is cleared.
3. TO bit of the STATUS register is set.
4. CPU clock is disabled.
5. 31 kHz LFINTOSC is unaffected and peripherals
that operate from it may continue operation in
Sleep.
6. Timer1 oscillator is unaffected and peripherals
that operate from it may continue operation in
Sleep.
7. ADC is unaffected, if the dedicated FRC clock is
selected.
8. Capacitive Sensing oscillator is unaffected.
9. I/O ports maintain the status they had before
SLEEP was executed (driving high, low or high-
impedance).
10. Resets other than WDT are not affected by
Sleep mode.
Refer to individual chapters for more details on
peripheral operation during Sleep.
To minimize current consumption, the following condi-
tions should be considered:
• I/O pins should not be floating
• External circuitry sinking current from I/O pins
• Internal circuitry sourcing current from I/O pins
• Current draw from pins with internal weak pull-ups
• Modules using 31 kHz LFINTOSC
• Modules using Timer1 oscillator
I/O pins that are high-impedance inputs should be
pulled to VDD or VSS externally to avoid switching
currents caused by floating inputs.
Examples of internal circuitry that might be sourcing
current include modules such as the DAC and FVR
modules. See Section 16.0 “Digital-to-Analog
Converter (DAC) Module” and Section 14.0 “Fixed
Voltage Reference (FVR)” for more information on
these modules.
9.1 Wake-up from Sleep
The device can wake-up from Sleep through one of the
following events:
1. External Reset input on MCLR pin, if enabled
2. BOR Reset, if enabled
3. POR Reset
4. Watchdog Timer, if enabled
5. Any external interrupt
6. Interrupts by peripherals capable of running dur-
ing Sleep (see individual peripheral for more
information)
The first three events will cause a device Reset. The
last three events are considered a continuation of pro-
gram execution. To determine whether a device Reset
or wake-up event occurred, refer to Section 7.10
“Determining the Cause of a Reset”.
When the SLEEP instruction is being executed, the next
instruction (PC + 1) is prefetched. For the device to
wake-up through an interrupt event, the corresponding
interrupt enable bit must be enabled. Wake-up will
occur regardless of the state of the GIE bit. If the GIE
bit is disabled, the device continues execution at the
instruction after the SLEEP instruction. If the GIE bit is
enabled, the device executes the instruction after the
SLEEP instruction, the device will call the Interrupt Ser-
vice Routine. In cases where the execution of the
instruction following SLEEP is not desirable, the user
should have a NOP after the SLEEP instruction.
The WDT is cleared when the device wakes up from
Sleep, regardless of the source of wake-up.
PIC12F/LF1822/16F/LF1823
DS41413A-page 96 Preliminary 2010 Microchip Technology Inc.
9.1.1 WAKE-UP USING INTERRUPTS
When global interrupts are disabled (GIE cleared) and
any interrupt source has both its interrupt enable bit
and interrupt flag bit set, one of the following will occur:
• If the interrupt occurs before the execution of a
SLEEP instruction
-SLEEP instruction will execute as a NOP.
- WDT and WDT prescaler will not be cleared
-TO
bit of the STATUS register will not be set
-PD
bit of the STATUS register will not be
cleared.
• If the interrupt occurs during or after the execu-
tion of a SLEEP instruction
-SLEEP instruction will be completely exe-
cuted
- Device will immediately wake-up from Sleep
- WDT and WDT prescaler will be cleared
-TO
bit of the STATUS register will be set
-PD bit of the STATUS register will be cleared.
Even if the flag bits were checked before executing a
SLEEP instruction, it may be possible for flag bits to
become set before the SLEEP instruction completes. To
determine whether a SLEEP instruction executed, test
the PD bit. If the PD bit is set, the SLEEP instruction
was executed as a NOP.
FIGURE 9-1: WAKE-UP FROM SLEEP THROUGH INTERRUPT
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1(1)
CLKOUT(2)
Interrupt flag
GIE bit
(INTCON reg.)
Instruction Flow
PC
Instruction
Fetched
Instruction
Executed
PC PC + 1 PC + 2
Inst(PC) = Sleep
Inst(PC - 1)
Inst(PC + 1)
Sleep
Processor in
Sleep
Interrupt Latency(4)
Inst(PC + 2)
Inst(PC + 1)
Inst(0004h) Inst(0005h)
Inst(0004h)
Dummy Cycle
PC + 2 0004h 0005h
Dummy Cycle
TOST(3)
PC + 2
Note 1: XT, HS or LP Oscillator mode assumed.
2: CLKOUT is not available in XT, HS, or LP Oscillator modes, but shown here for timing reference.
3: TOST = 1024 TOSC (drawing not to scale). This delay applies only to XT, HS or LP Oscillator modes.
4: GIE = 1 assumed. In this case after wake-up, the processor calls the ISR at 0004h. If GIE = 0, execution will continue in-line.
2010 Microchip Technology Inc. Preliminary DS41413A-page 97
PIC12F/LF1822/16F/LF1823
TABLE 9-1: SUMMARY OF REGISTERS ASSOCIATED WITH POWER-DOWN MODE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on
Page
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
IOCAF —— IOCAF5 IOCAF4 IOCAF3 IOCAF2 IOCAF1 IOCAF0 128
IOCAN —— IOCAN5 IOCAN4 IOCAN3 IOCAN2 IOCAN1 IOCAN0 128
IOCAP —— IOCAP5 IOCAP4 IOCAP3 IOCAP2 IOCAP1 IOCAP0 128
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE ———91
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF ———93
STATUS — — —TOPD ZDC C24
WDTCON —— WDTPS4 WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN 101
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used in Power-down mode.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 98 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 99
PIC12F/LF1822/16F/LF1823
10.0 WATCHDOG TIMER
The Watchdog Timer is a system timer that generates
a Reset if the firmware does not issue a CLRWDT
instruction within the time-out period. The Watchdog
Timer is typically used to recover the system from
unexpected events.
The WDT has the following features:
• Independent clock source
• Multiple operating modes
- WDT is always on
- WDT is off when in Sleep
- WDT is controlled by software
- WDT is always off
• Configurable time-out period is from 1 ms to 268
seconds (typical)
• Multiple Reset conditions
• Operation during Sleep
FIGURE 10-1: WATCHDOG TIMER BLOCK DIAGRAM
LFINTOSC 23-bit Programmable
Prescaler WDT WDT Time-out
WDTPS<4:0>
SWDTEN
Sleep
WDTE<1:0> = 11
WDTE<1:0> = 01
WDTE<1:0> = 10
PIC12F/LF1822/16F/LF1823
DS41413A-page 100 Preliminary 2010 Microchip Technology Inc.
10.1 Independent Clock Source
The WDT derives its time base from the 31 kHz
LFINTOSC internal oscillator.
10.2 WDT Operating Modes
The Watchdog Timer module has four operating modes
controlled by the WDTE<1:0> bits in Configuration
Word 1. See Table 10-1.
10.2.1 WDT IS ALWAYS ON
When the WDTE bits of Configuration Word 1 are set to
‘11’, the WDT is always on.
WDT protection is active during Sleep.
10.2.2 WDT IS OFF IN SLEEP
When the WDTE bits of Configuration Word 1 are set to
‘10’, the WDT is on, except in Sleep.
WDT protection is not active during Sleep.
10.2.3 WDT CONTROLLED BY SOFTWARE
When the WDTE bits of Configuration Word 1 are set to
‘01’, the WDT is controlled by the SWDTEN bit of the
WDTCON register.
WDT protection is unchanged by Sleep. See
Table 10-1 for more details.
TABLE 10-1: WDT OPERATING MODES
10.3 Time-Out Period
The WDTPS bits of the WDTCON register set the
time-out period from 1ms to 268 seconds. After a
Reset, the default time-out period is 2 seconds.
10.4 Clearing the WDT
The WDT is cleared when any of the following condi-
tions occur:
•Any Reset
•CLRWDT instruction is executed
• Device enters Sleep
• Device wakes up from Sleep
• Oscillator fail event
• WDT is disabled
•OST is running
See Table 10-2 for more information.
10.5 Operation During Sleep
When the device enters Sleep, the WDT is cleared. If
the WDT is enabled during Sleep, the WDT resumes
counting.
When the device exits Sleep, the WDT is cleared
again. The WDT remains clear until the OST, if
enabled, completes. See Section 5.0 “Oscillator
Module (With Fail-Safe Clock Monitor)” for more
information on the OST.
When a WDT time-out occurs while the device is in
Sleep, no Reset is generated. Instead, the device
wakes up and resumes operation. The TO and PD bits
in the STATUS register are changed to indicate the
event. See Section 3.0 “Memory Organization” and
The STATUS register (Register 3-1) for more
information.
WDTE
Config bits SWDTEN Device
Mode
WDT
Mode
WDT_ON (11)XXActive
WDT_NSLEEP (10) X Awake Active
WDT_NSLEEP (10)XSleep Disabled
WDT_SWDTEN (01)1XActive
WDT_SWDTEN (01)0X Disabled
WDT_OFF (00)XX Disabled
TABLE 10-2: WDT CLEARING CONDITIONS
Conditions WDT
WDTE<1:0> = 00
Cleared
WDTE<1:0> = 01 and SWDTEN = 0
WDTE<1:0> = 10 and enter Sleep
CLRWDT Command
Oscillator Fail Detected
Exit Sleep + System Clock = T1OSC, EXTRC, INTOSC, EXTCLK
Exit Sleep + System Clock = XT, HS, LP Cleared until the end of OST
Change INTOSC divider (IRCF bits) Unaffected
2010 Microchip Technology Inc. Preliminary DS41413A-page 101
PIC12F/LF1822/16F/LF1823
REGISTER 10-1: WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0 U-0 R/W-0/0 R/W-1/1 R/W-0/0 R/W-1/1 R/W-1/1 R/W-0/0
—— WDTPS4 WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -m/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-1 WDTPS<4:0>: Watchdog Timer Period Select bits
Bit Value = Prescale Rate
00000 = 1:32 (Interval 1 ms typ)
00001 = 1:64 (Interval 2 ms typ)
00010 = 1:128 (Interval 4 ms typ)
00011 = 1:256 (Interval 8 ms typ)
00100 = 1:512 (Interval 16 ms typ)
00101 = 1:1024 (Interval 32 ms typ)
00110 = 1:2048 (Interval 64 ms typ)
00111 = 1:4096 (Interval 128 ms typ)
01000 = 1:8192 (Interval 256 ms typ)
01001 = 1:16384 (Interval 512 ms typ)
01010 = 1:32768 (Interval 1s typ)
01011 = 1:65536 (Interval 2s typ) (Reset value)
01100 = 1:131072 (217) (Interval 4s typ)
01101 = 1:262144 (218) (Interval 8s typ)
01110 = 1:524288 (219) (Interval 16s typ)
01111 = 1:1048576 (220) (Interval 32s typ)
10000 = 1:2097152 (221) (Interval 64s typ)
10001 = 1:4194304 (222) (Interval 128s typ)
10010 = 1:8388608 (223) (Interval 256s typ)
10011 = Reserved. Results in minimum interval (1:32)
•
•
•
11111 = Reserved. Results in minimum interval (1:32)
bit 0 SWDTEN: Software Enable/Disable for Watchdog Timer bit
If WDTE<1:0> = 00:
This bit is ignored.
If WDTE<1:0> = 01:
1 = WDT is turned on
0 = WDT is turned off
If WDTE<1:0> = 1x:
This bit is ignored.
PIC12F/LF1822/16F/LF1823
DS41413A-page 102 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 103
PIC12F/LF1822/16F/LF1823
11.0 DATA EEPROM AND FLASH
PROGRAM MEMORY
CONTROL
The Data EEPROM and Flash program memory are
readable and writable during normal operation (full VDD
range). These memories are not directly mapped in the
register file space. Instead, they are indirectly
addressed through the Special Function Registers
(SFRs). There are six SFRs used to access these
memories:
• EECON1
• EECON2
• EEDATL
•EEDATH
• EEADRL
•EEADRH
When interfacing the data memory block, EEDATL
holds the 8-bit data for read/write, and EEADRL holds
the address of the EEDATL location being accessed.
These devices have 256 bytes of data EEPROM with
an address range from 0h to 0FFh.
When accessing the program memory block, the EED-
ATH:EEDATL register pair forms a 2-byte word that
holds the 14-bit data for read/write, and the EEADRL
and EEADRH registers form a 2-byte word that holds
the 15-bit address of the program memory location
being read.
The EEPROM data memory allows byte read and write.
An EEPROM byte write automatically erases the loca-
tion and writes the new data (erase before write).
The write time is controlled by an on-chip timer. The
write/erase voltages are generated by an on-chip
charge pump rated to operate over the voltage range of
the device for byte or word operations.
Depending on the setting of the Flash Program
Memory Self Write Enable bits WRT<1:0> of the
Configuration Word 2, the device may or may not be
able to write certain blocks of the program memory.
However, reads from the program memory are always
allowed.
When the device is code-protected, the device
programmer can no longer access data or program
memory. When code-protected, the CPU may continue
to read and write the data EEPROM memory and Flash
program memory.
11.1 EEADRL and EEADRH Registers
The EEADRH:EEADRL register pair can address up to
a maximum of 256 bytes of data EEPROM or up to a
maximum of 32K words of program memory.
When selecting a program address value, the MSB of
the address is written to the EEADRH register and the
LSB is written to the EEADRL register. When selecting
a EEPROM address value, only the LSB of the address
is written to the EEADRL register.
11.1.1 EECON1 AND EECON2 REGISTERS
EECON1 is the control register for EE memory
accesses.
Control bit EEPGD determines if the access will be a
program or data memory access. When clear, any
subsequent operations will operate on the EEPROM
memory. When set, any subsequent operations will
operate on the program memory. On Reset, EEPROM is
selected by default.
Control bits RD and WR initiate read and write,
respectively. These bits cannot be cleared, only set, in
software. They are cleared in hardware at completion
of the read or write operation. The inability to clear the
WR bit in software prevents the accidental, premature
termination of a write operation.
The WREN bit, when set, will allow a write operation to
occur. On power-up, the WREN bit is clear. The
WRERR bit is set when a write operation is interrupted
by a Reset during normal operation. In these situations,
following Reset, the user can check the WRERR bit
and execute the appropriate error handling routine.
Interrupt flag bit EEIF of the PIR2 register is set when
write is complete. It must be cleared in the software.
Reading EECON2 will read all ‘0’s. The EECON2 reg-
ister is used exclusively in the data EEPROM write
sequence. To enable writes, a specific pattern must be
written to EECON2.
PIC12F/LF1822/16F/LF1823
DS41413A-page 104 Preliminary 2010 Microchip Technology Inc.
11.2 Using the Data EEPROM
The data EEPROM is a high-endurance, byte address-
able array that has been optimized for the storage of
frequently changing information (e.g., program vari-
ables or other data that are updated often). When vari-
ables in one section change frequently, while variables
in another section do not change, it is possible to
exceed the total number of write cycles to the
EEPROM without exceeding the total number of write
cycles to a single byte. Refer to Section 29.0 “Electri-
cal Specifications”. If this is the case, then a refresh
of the array must be performed. For this reason, vari-
ables that change infrequently (such as constants, IDs,
calibration, etc.) should be stored in Flash program
memory.
11.2.1 READING THE DATA EEPROM
MEMORY
To read a data memory location, the user must write the
address to the EEADRL register, clear the EEPGD and
CFGS control bits of the EECON1 register, and then
set control bit RD. The data is available at the very next
cycle, in the EEDATL register; therefore, it can be read
in the next instruction. EEDATL will hold this value until
another read or until it is written to by the user (during
a write operation).
EXAMPLE 11-1: DATA EEPROM READ
11.2.2 WRITING TO THE DATA EEPROM
MEMORY
To write an EEPROM data location, the user must first
write the address to the EEADRL register and the data
to the EEDATL register. Then the user must follow a
specific sequence to initiate the write for each byte.
The write will not initiate if the above sequence is not
followed exactly (write 55h to EECON2, write AAh to
EECON2, then set WR bit) for each byte. Interrupts
should be disabled during this code segment.
Additionally, the WREN bit in EECON1 must be set to
enable write. This mechanism prevents accidental
writes to data EEPROM due to errant (unexpected)
code execution (i.e., lost programs). The user should
keep the WREN bit clear at all times, except when
updating EEPROM. The WREN bit is not cleared
by hardware.
After a write sequence has been initiated, clearing the
WREN bit will not affect this write cycle. The WR bit will
be inhibited from being set unless the WREN bit is set.
At the completion of the write cycle, the WR bit is
cleared in hardware and the EE Write Complete
Interrupt Flag bit (EEIF) is set. The user can either
enable this interrupt or poll this bit. EEIF must be
cleared by software.
11.2.3 PROTECTION AGAINST SPURIOUS
WRITE
There are conditions when the user may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built-in. On power-up, WREN is cleared. Also, the
Power-up Timer (64 ms duration) prevents EEPROM
write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during:
• Brown-out
• Power Glitch
• Software Malfunction
11.2.4 DATA EEPROM OPERATION
DURING CODE-PROTECT
Data memory can be code-protected by programming
the CPD bit in the Configuration Word 1 (Register 5-1)
to ‘0’.
When the data memory is code-protected, only the
CPU is able to read and write data to the data
EEPROM. It is recommended to code-protect the pro-
gram memory when code-protecting data memory.
This prevents anyone from replacing your program with
a program that will access the contents of the data
EEPROM.
Note: Data EEPROM can be read regardless of
the setting of the CPD bit.
BANKSEL EEADRL ;
MOVLW DATA_EE_ADDR ;
MOVWF EEADRL ;Data Memory
;Address to read
BCF EECON1, CFGS ;Deselect Config space
BCF EECON1, EEPGD;Point to DATA memory
BSF EECON1, RD ;EE Read
MOVF EEDATL, W ;W = EEDATL
2010 Microchip Technology Inc. Preliminary DS41413A-page 105
PIC12F/LF1822/16F/LF1823
EXAMPLE 11-2: DATA EEPROM WRITE
FIGURE 11-1: FLASH PROGRAM MEMORY READ CYCLE EXECUTION
BANKSEL EEADRL ;
MOVLW DATA_EE_ADDR ;
MOVWF EEADRL ;Data Memory Address to write
MOVLW DATA_EE_DATA ;
MOVWF EEDATL ;Data Memory Value to write
BCF EECON1, CFGS ;Deselect Configuration space
BCF EECON1, EEPGD ;Point to DATA memory
BSF EECON1, WREN ;Enable writes
BCF INTCON, GIE ;Disable INTs.
MOVLW 55h ;
MOVWF EECON2 ;Write 55h
MOVLW 0AAh ;
MOVWF EECON2 ;Write AAh
BSF EECON1, WR ;Set WR bit to begin write
BSF INTCON, GIE ;Enable Interrupts
BCF EECON1, WREN ;Disable writes
BTFSC EECON1, WR ;Wait for write to complete
GOTO $-2 ;Done
Required
Sequence
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
BSF EECON1,RD
executed here INSTR(PC + 1)
executed here Forced NOP
executed here
PC
PC + 1 EEADRH,EEADRL PC+3 PC + 5
Flash ADDR
RD bit
EEDATH,EEDATL
PC + 3 PC + 4
INSTR (PC + 1)
INSTR(PC - 1)
executed here INSTR(PC + 3)
executed here INSTR(PC + 4)
executed here
Flash Data
EEDATH
EEDATL
Register
EERHLT
INSTR (PC) INSTR (PC + 3) INSTR (PC + 4)
PIC12F/LF1822/16F/LF1823
DS41413A-page 106 Preliminary 2010 Microchip Technology Inc.
11.3 Flash Program Memory Overview
It is important to understand the Flash program mem-
ory structure for erase and programming operations.
Flash Program memory is arranged in rows. A row con-
sists of a fixed number of 14-bit program memory
words. A row is the minimum block size that can be
erased by user software.
Flash program memory may only be written or erased
if the destination address is in a segment of memory
that is not write-protected, as defined in bits WRT<1:0>
of Configuration Word 2.
After a row has been erased, the user can reprogram
all or a portion of this row. Data to be written into the
program memory row is written to 14-bit wide data write
latches. These write latches are not directly accessible
to the user, but may be loaded via sequential writes to
the EEDATH:EEDATL register pair.
The number of data write latches is not equivalent to
the number of row locations. During programming, user
software will need to fill the set of write latches and ini-
tiate a programming operation multiple times in order to
fully reprogram an erased row. For example, a device
with a row size of 32 words and eight write latches will
need to load the write latches with data and initiate a
programming operation four times.
The size of a program memory row and the number of
program memory write latches may vary by device.
See Table 11-1 for details.
11.3.1 READING THE FLASH PROGRAM
MEMORY
To read a program memory location, the user must:
1. Write the Least and Most Significant address
bits to the EEADRH:EEADRL register pair.
2. Clear the CFGS bit of the EECON1 register.
3. Set the EEPGD control bit of the EECON1
register.
4. Then, set control bit RD of the EECON1 register.
Once the read control bit is set, the program memory
Flash controller will use the second instruction cycle to
read the data. This causes the second instruction
immediately following the “BSF EECON1,RD” instruction
to be ignored. The data is available in the very next cycle,
in the EEDATH:EEDATL register pair; therefore, it can
be read as two bytes in the following instructions.
EEDATH:EEDATL register pair will hold this value until
another read or until it is written to by the user.
Note: If the user wants to modify only a portion
of a previously programmed row, then the
contents of the entire row must be read
and saved in RAM prior to the erase.
TABLE 11-1: FLASH MEMORY
ORGANIZATION BY DEVICE
Device
Erase Block
(Row) Size/
Boundary
Number of
Write Latches/
Boundary
PIC12F/LF1822/
16F/LF1823
16 words,
EEADRL<3:0>
= 0000
16 words,
EEADRL<3:0>
= 0000
Note 1: The two instructions following a program
memory read are required to be NOPs.
This prevents the user from executing a
two-cycle instruction on the next
instruction after the RD bit is set.
2: Flash program memory can be read
regardless of the setting of the CP bit.
2010 Microchip Technology Inc. Preliminary DS41413A-page 107
PIC12F/LF1822/16F/LF1823
EXAMPLE 11-3: FLASH PROGRAM MEMORY READ
* This code block will read 1 word of program
* memory at the memory address:
PROG_ADDR_HI : PROG_ADDR_LO
* data will be returned in the variables;
* PROG_DATA_HI, PROG_DATA_LO
BANKSEL EEADRL ; Select Bank for EEPROM registers
MOVLW PROG_ADDR_LO ;
MOVWF EEADRL ; Store LSB of address
MOVLW PROG_ADDR_HI ;
MOVWL EEADRH ; Store MSB of address
BCF EECON1,CFGS ; Do not select Configuration Space
BSF EECON1,EEPGD ; Select Program Memory
BCF INTCON,GIE ; Disable interrupts
BSF EECON1,RD ; Initiate read
NOP ; Executed (Figure 11-1)
NOP ; Ignored (Figure 11-1)
BSF INTCON,GIE ; Restore interrupts
MOVF EEDATL,W ; Get LSB of word
MOVWF PROG_DATA_LO ; Store in user location
MOVF EEDATH,W ; Get MSB of word
MOVWF PROG_DATA_HI ; Store in user location
PIC12F/LF1822/16F/LF1823
DS41413A-page 108 Preliminary 2010 Microchip Technology Inc.
11.3.2 ERASING FLASH PROGRAM
MEMORY
While executing code, program memory can only be
erased by rows. To erase a row:
1. Load the EEADRH:EEADRL register pair with
the address of new row to be erased.
2. Clear the CFGS bit of the EECON1 register.
3. Set the EEPGD, FREE, and WREN bits of the
EECON1 register.
4. Write 55h, then AAh, to EECON2 (Flash
programming unlock sequence).
5. Set control bit WR of the EECON1 register to
begin the erase operation.
6. Poll the FREE bit in the EECON1 register to
determine when the row erase has completed.
See Example 11-4.
After the “BSF EECON1,WR” instruction, the processor
requires two cycles to set up the erase operation. The
user must place two NOP instructions after the WR bit is
set. The processor will halt internal operations for the
typical 2 ms erase time. This is not Sleep mode as the
clocks and peripherals will continue to run. After the
erase cycle, the processor will resume operation with
the third instruction after the EECON1 write instruction.
11.3.3 WRITING TO FLASH PROGRAM
MEMORY
Program memory is programmed using the following
steps:
1. Load the starting address of the word(s) to be
programmed.
2. Load the write latches with data.
3. Initiate a programming operation.
4. Repeat steps 1 through 3 until all data is written.
Before writing to program memory, the word(s) to be
written must be erased or previously unwritten. Pro-
gram memory can only be erased one row at a time. No
automatic erase occurs upon the initiation of the write.
Program memory can be written one or more words at
a time. The maximum number of words written at one
time is equal to the number of write latches. See
Figure 11-2 (block writes to program memory with 16
write latches) for more details. The write latches are
aligned to the address boundary defined by EEADRL
as shown in Table 11-1. Write operations do not cross
these boundaries. At the completion of a program
memory write operation, the write latches are reset to
contain 0x3FFF.
The following steps should be completed to load the
write latches and program a block of program memory.
These steps are divided into two parts. First, all write
latches are loaded with data except for the last program
memory location. Then, the last write latch is loaded
and the programming sequence is initiated. A special
unlock sequence is required to load a write latch with
data or initiate a Flash programming operation. This
unlock sequence should not be interrupted.
1. Set the EEPGD and WREN bits of the EECON1
register.
2. Clear the CFGS bit of the EECON1 register.
3. Set the LWLO bit of the EECON1 register. When
the LWLO bit of the EECON1 register is ‘1’, the
write sequence will only load the write latches
and will not initiate the write to Flash program
memory.
4. Load the EEADRH:EEADRL register pair with
the address of the location to be written.
5. Load the EEDATH:EEDATL register pair with
the program memory data to be written.
6. Write 55h, then AAh, to EECON2, then set the
WR bit of the EECON1 register (Flash
programming unlock sequence). The write latch
is now loaded.
7. Increment the EEADRH:EEADRL register pair
to point to the next location.
8. Repeat steps 5 through 7 until all but the last
write latch has been loaded.
9. Clear the LWLO bit of the EECON1 register.
When the LWLO bit of the EECON1 register is
‘0’, the write sequence will initiate the write to
Flash program memory.
10. Load the EEDATH:EEDATL register pair with
the program memory data to be written.
11. Write 55h, then AAh, to EECON2, then set the
WR bit of the EECON1 register (Flash
programming unlock sequence). The entire
latch block is now written to Flash program
memory.
It is not necessary to load the entire write latch block
with user program data. However, the entire write latch
block will be written to program memory.
An example of the complete write sequence for eight
words is shown in Example 11-5. The initial address is
loaded into the EEADRH:EEADRL register pair; the
eight words of data are loaded using indirect address-
ing.
Note: The code sequence provided in
Example 11-5 must be repeated multiple
times to fully program an erased program
memory row.
2010 Microchip Technology Inc. Preliminary DS41413A-page 109
PIC12F/LF1822/16F/LF1823
After the “BSF EECON1,WR” instruction, the processor
requires two cycles to set up the write operation. The
user must place two NOP instructions after the WR bit is
set. The processor will halt internal operations for the
typical 2 ms, only during the cycle in which the write
takes place (i.e., the last word of the block write). This
is not Sleep mode as the clocks and peripherals will
continue to run. The processor does not stall when
LWLO = 1, loading the write latches. After the write
cycle, the processor will resume operation with the third
instruction after the EECON1 write instruction.
FIGURE 11-2: BLOCK WRITES TO FLASH PROGRAM MEMORY WITH 16 WRITE LATCHES
14 14 14 14
Program Memory
Buffer Register
EEADRL<3:0> = 0000
Buffer Register
EEADRL<3:0> = 0001
Buffer Register
EEADRL<3:0> = 0010
Buffer Register
EEADRL<3:0> = 1111
EEDATA
EEDATH
75 07 0
68
First word of block
to be written
Last word of block
to be written
PIC12F/LF1822/16F/LF1823
DS41413A-page 110 Preliminary 2010 Microchip Technology Inc.
EXAMPLE 11-4: ERASING ONE ROW OF PROGRAM MEMORY
; This row erase routine assumes the following:
; 1. A valid address within the erase block is loaded in ADDRH:ADDRL
; 2. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F
BCF INTCON,GIE ; Disable ints so required sequences will execute properly
BANKSEL EEADRL
MOVF ADDRL,W ; Load lower 8 bits of erase address boundary
MOVWF EEADRL
MOVF ADDRH,W ; Load upper 6 bits of erase address boundary
MOVWF EEADRH
BSF EECON1,EEPGD ; Point to program memory
BCF EECON1,CFGS ; Not configuration space
BSF EECON1,FREE ; Specify an erase operation
BSF EECON1,WREN ; Enable writes
MOVLW 55h ; Start of required sequence to initiate erase
MOVWF EECON2 ; Write 55h
MOVLW 0AAh ;
MOVWF EECON2 ; Write AAh
BSF EECON1,WR ; Set WR bit to begin erase
NOP ; Any instructions here are ignored as processor
; halts to begin erase sequence
NOP ; Processor will stop here and wait for erase complete.
; after erase processor continues with 3rd instruction
BCF EECON1,WREN ; Disable writes
BSF INTCON,GIE ; Enable interrupts
Required
Sequence
2010 Microchip Technology Inc. Preliminary DS41413A-page 111
PIC12F/LF1822/16F/LF1823
EXAMPLE 11-5: WRITING TO FLASH PROGRAM MEMORY
; This write routine assumes the following:
; 1. The 16 bytes of data are loaded, starting at the address in DATA_ADDR
; 2. Each word of data to be written is made up of two adjacent bytes in DATA_ADDR,
; stored in little endian format
; 3. A valid starting address (the least significant bits = 000) is loaded in ADDRH:ADDRL
; 4. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F
;
BCF INTCON,GIE ; Disable ints so required sequences will execute properly
BANKSEL EEADRH ; Bank 3
MOVF ADDRH,W ; Load initial address
MOVWF EEADRH ;
MOVF ADDRL,W ;
MOVWF EEADRL ;
MOVLW LOW DATA_ADDR ; Load initial data address
MOVWF FSR0L ;
MOVLW HIGH DATA_ADDR ; Load initial data address
MOVWF FSR0H ;
BSF EECON1,EEPGD ; Point to program memory
BCF EECON1,CFGS ; Not configuration space
BSF EECON1,WREN ; Enable writes
BSF EECON1,LWLO ; Only Load Write Latches
LOOP
MOVIW FSR0++ ; Load first data byte into lower
MOVWF EEDATL ;
MOVIW FSR0++ ; Load second data byte into upper
MOVWF EEDATH ;
MOVF EEADRL,W ; Check if lower bits of address are '000'
XORLW 0x07 ; Check if we're on the last of 8 addresses
ANDLW 0x07 ;
BTFSC STATUS,Z ; Exit if last of eight words,
GOTO START_WRITE ;
MOVLW 55h ; Start of required write sequence:
MOVWF EECON2 ; Write 55h
MOVLW 0AAh ;
MOVWF EECON2 ; Write AAh
BSF EECON1,WR ; Set WR bit to begin write
NOP ; Any instructions here are ignored as processor
; halts to begin write sequence
NOP ; Processor will stop here and wait for write to complete.
; After write processor continues with 3rd instruction.
INCF EEADRL,F ; Still loading latches Increment address
GOTO LOOP ; Write next latches
START_WRITE
BCF EECON1,LWLO ; No more loading latches - Actually start Flash program
; memory write
MOVLW 55h ; Start of required write sequence:
MOVWF EECON2 ; Write 55h
MOVLW 0AAh ;
MOVWF EECON2 ; Write AAh
BSF EECON1,WR ; Set WR bit to begin write
NOP ; Any instructions here are ignored as processor
; halts to begin write sequence
NOP ; Processor will stop here and wait for write complete.
; after write processor continues with 3rd instruction
BCF EECON1,WREN ; Disable writes
BSF INTCON,GIE ; Enable interrupts
Required
Sequence
Required
Sequence
PIC12F/LF1822/16F/LF1823
DS41413A-page 112 Preliminary 2010 Microchip Technology Inc.
11.4 Modifying Flash Program Memory
When modifying existing data in a program memory
row, and data within that row must be preserved, it must
first be read and saved in a RAM image. Program
memory is modified using the following steps:
1. Load the starting address of the row to be mod-
ified.
2. Read the existing data from the row into a RAM
image.
3. Modify the RAM image to contain the new data
to be written into program memory.
4. Load the starting address of the row to be rewrit-
ten.
5. Erase the program memory row.
6. Load the write latches with data from the RAM
image.
7. Initiate a programming operation.
8. Repeat steps 6 and 7 as many times as required
to reprogram the erased row.
11.5 User ID, Device ID and
Configuration Word Access
Instead of accessing program memory or EEPROM
data memory, the User ID’s, Device ID/Revision ID and
Configuration Words can be accessed when CFGS = 1
in the EECON1 register. This is the region that would
be pointed to by PC<15> = 1, but not all addresses are
accessible. Different access may exist for reads and
writes. Refer to Table 11-2.
When read access is initiated on an address outside
the parameters listed in Table 11-2, the EEDATH:EED-
ATL register pair is cleared.
TABLE 11-2: USER ID, DEVICE ID AND CONFIGURATION WORD ACCESS (CFGS = 1)
EXAMPLE 11-3: CONFIGURATION WORD AND DEVICE ID ACCESS
Address Function Read Access Write Access
8000h-8003h User IDs Yes Yes
8006h Device ID/Revision ID Yes No
8007h-8008h Configuration Words 1 and 2 Yes No
* This code block will read 1 word of program memory at the memory address:
* PROG_ADDR_LO (must be 00h-08h) data will be returned in the variables;
* PROG_DATA_HI, PROG_DATA_LO
BANKSEL EEADRL ; Select correct Bank
MOVLW PROG_ADDR_LO ;
MOVWF EEADRL ; Store LSB of address
CLRF EEADRH ; Clear MSB of address
BSF EECON1,CFGS ; Select Configuration Space
BCF INTCON,GIE ; Disable interrupts
BSF EECON1,RD ; Initiate read
NOP ; Executed (See Figure 11-1)
NOP ; Ignored (See Figure 11-1)
BSF INTCON,GIE ; Restore interrupts
MOVF EEDATL,W ; Get LSB of word
MOVWF PROG_DATA_LO ; Store in user location
MOVF EEDATH,W ; Get MSB of word
MOVWF PROG_DATA_HI ; Store in user location
2010 Microchip Technology Inc. Preliminary DS41413A-page 113
PIC12F/LF1822/16F/LF1823
11.6 Write Verify
Depending on the application, good programming
practice may dictate that the value written to the data
EEPROM or program memory should be verified (see
Example 11-6) to the desired value to be written.
Example 11-6 shows how to verify a write to EEPROM.
EXAMPLE 11-6: EEPROM WRITE VERIFY
BANKSEL EEDATL ;
MOVF EEDATL, W ;EEDATL not changed
;from previous write
BSF EECON1, RD ;YES, Read the
;value written
XORWF EEDATL, W ;
BTFSS STATUS, Z ;Is data the same
GOTO WRITE_ERR ;No, handle error
: ;Yes, continue
PIC12F/LF1822/16F/LF1823
DS41413A-page 114 Preliminary 2010 Microchip Technology Inc.
REGISTER 11-1: EEDATL: EEPROM DATA REGISTER
R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
EEDAT<7:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-0 EEDAT<7:0>: Read/write value for EEPROM data byte or Least Significant bits of program memory
REGISTER 11-2: EEDATH: EEPROM DATA HIGH BYTE REGISTER
U-0 U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
—— EEDAT<13:8>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 EEDAT<13:8>: Read/write value for Most Significant bits of program memory
REGISTER 11-3: EEADRL: EEPROM ADDRESS REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
EEADR<7:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-0 EEADR<7:0>: Specifies the Least Significant bits for program memory address or EEPROM address
REGISTER 11-4: EEADRH: EEPROM ADDRESS HIGH BYTE REGISTER
U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
— EEADR<14:8>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 Unimplemented: Read as ‘0’
bit 6-0 EEADR<14:8>: Specifies the Most Significant bits for program memory address or EEPROM address
2010 Microchip Technology Inc. Preliminary DS41413A-page 115
PIC12F/LF1822/16F/LF1823
REGISTER 11-5: EECON1: EEPROM CONTROL 1 REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W/HC-0/0 R/W-x/q R/W-0/0 R/S/HC-0/0 R/S/HC-0/0
EEPGD CFGS LWLO FREE WRERR WREN WR RD
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
S = Bit can only be set x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared HC = Bit is cleared by hardware
bit 7 EEPGD: Flash Program/Data EEPROM Memory Select bit
1 = Accesses program space Flash memory
0 = Accesses data EEPROM memory
bit 6 CFGS: Flash Program/Data EEPROM or Configuration Select bit
1 = Accesses Configuration, User ID and Device ID Registers
0 = Accesses Flash Program or data EEPROM Memory
bit 5 LWLO: Load Write Latches Only bit
If CFGS = 1 (Configuration space) OR CFGS = 0 and EEPGD = 1 (program Flash):
1 = The next WR command does not initiate a write; only the program memory latches are
updated.
0 = The next WR command writes a value from EEDATH:EEDATL into program memory latches
and initiates a write of all the data stored in the program memory latches.
If CFGS = 0 and EEPGD = 0: (Accessing data EEPROM)
LWLO is ignored. The next WR command initiates a write to the data EEPROM.
bit 4 FREE: Program Flash Erase Enable bit
If CFGS = 1 (Configuration space) OR CFGS = 0 and EEPGD = 1 (program Flash):
1 = Performs an erase operation on the next WR command (cleared by hardware after comple-
tion of erase).
0 = Performs a write operation on the next WR command.
If EEPGD = 0 and CFGS = 0: (Accessing data EEPROM)
FREE is ignored. The next WR command will initiate both a erase cycle and a write cycle.
bit 3 WRERR: EEPROM Error Flag bit
1 = Condition indicates an improper program or erase sequence attempt or termination (bit is set
automatically on any set attempt (write ‘1’) of the WR bit).
0 = The program or erase operation completed normally.
bit 2 WREN: Program/Erase Enable bit
1 = Allows program/erase cycles
0 = Inhibits programming/erasing of program Flash and data EEPROM
bit 1 WR: Write Control bit
1 = Initiates a program Flash or data EEPROM program/erase operation.
The operation is self-timed and the bit is cleared by hardware once operation is complete.
The WR bit can only be set (not cleared) in software.
0 = Program/erase operation to the Flash or data EEPROM is complete and inactive.
bit 0 RD: Read Control bit
1 = Initiates an program Flash or data EEPROM read. Read takes one cycle. RD is cleared in
hardware. The RD bit can only be set (not cleared) in software.
0 = Does not initiate a program Flash or data EEPROM data read.
PIC12F/LF1822/16F/LF1823
DS41413A-page 116 Preliminary 2010 Microchip Technology Inc.
TABLE 11-3: SUMMARY OF REGISTERS ASSOCIATED WITH DATA EEPROM
REGISTER 11-6: EECON2: EEPROM CONTROL 2 REGISTER
W-0/0 W-0/0 W-0/0 W-0/0 W-0/0 W-0/0 W-0/0 W-0/0
EEPROM Control Register 2
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
S = Bit can only be set x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-0 Data EEPROM Unlock Pattern bits
To unlock writes, a 55h must be written first, followed by an AAh, before setting the WR bit of the
EECON1 register. The value written to this register is used to unlock the writes. There are specific
timing requirements on these writes. Refer to Section 11.2.2 “Writing to the Data EEPROM
Memory” for more information.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
EECON1 EEPGD CFGS LWLO FREE WRERR WREN WR RD 115
EECON2 EEPROM Control Register 2 (not a physical register) 116*
EEADRL EEADRL<7:0> 114
EEADRH — EEADRH<6:0 114
EEDATL EEDATL<7:0> 114
EEDATH —— EEDATH<5:0> 114
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE ———91
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF ———93
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by Data EEPROM module.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 117
PIC12F/LF1822/16F/LF1823
12.0 I/O PORTS
Depending on the device selected and peripherals
enabled, there are up to two ports available. In general,
when a peripheral is enabled, that pin may not be used
as a general purpose I/O pin.
Each port has three registers for its operation. These
registers are:
• TRISx registers (data direction register)
• PORTx registers (reads the levels on the pins of
the device)
• LATx registers (output latch)
The Data Latch (LATx registers) is useful for
read-modify-write operations on the value that the I/O
pins are driving.
A write operation to the LATx register has the same
affect as a write to the corresponding PORTx register.
A read of the LATx register reads of the values held in
the I/O PORT latches, while a read of the PORTx
register reads the actual I/O pin value.
Ports with analog functions also have an ANSELx
register which can disable the digital input and save
power. A simplified model of a generic I/O port, without
the interfaces to other peripherals, is shown in
Figure 12-1.
FIGURE 12-1: GENERIC I/O PORT
OPERATION
12.1 Alternate Pin Function
The Alternate Pin Function Control (APFCON)
registers are used to steer specific peripheral input and
output functions between different pins. The APFCON
registers are shown in Register 12-1. For this device
family, the following functions can be moved between
different pins.
• RX/DT/TX/CK
•SDO
•SS
(Slave Select)
•T1G
•P1B
• CCP1/P1A
These bits have no effect on the values of any TRIS
register. PORT and TRIS overrides will be routed to the
correct pin. The unselected pin will be unaffected.
QD
CK
Write LATx
Data Register
I/O pin
Read PORTx
Write PORTx
TRISx
Read LATx
Data Bus
To peripherals
ANSELx
VDD
VSS
PIC12F/LF1822/16F/LF1823
DS41413A-page 118 Preliminary 2010 Microchip Technology Inc.
REGISTER 12-1: APFCON: ALTERNATE PIN FUNCTION CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
RXDTSEL SDOSEL SSSEL —T1GSEL TXCKSEL P1BSEL CCP1SEL
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 RXDTSEL: Pin Selection bit
For 8 Pin Devices (PIC12F/LF1822):
0 = RX/DT function is on RA1
1 = RX/DT function is on RA5
For 14 Pin Devices (PIC16F/LF1823):
0 = RX/DT function is on RC5
1 = RX/DT function is on RA1
bit 6 SDOSEL: Pin Selection bit
For 8 Pin Devices (PIC12F/LF1822):
0 = SDO function is on RA0
1 = SDO function is on RA4
For 14 Pin Devices (PIC16F/LF1823):
0 = SDO function is on RC2
1 = SDO function is on RA4
bit 5 SSSEL: Pin Selection bit
For 8 Pin Devices (PIC12F/LF1822):
0 =SS
function is on RA3
1 =SS
function is on RA0
For 14 Pin Devices (PIC16F/LF1823):
0 =SS
function is on RC3
1 =SS
function is on RA3
bit 4 Unimplemented: Read as ‘0’
bit 3 T1GSEL: Pin Selection bit
0 = T1G function is on RA4
1 = T1G function is on RA3
bit 2 TXCKSEL: Pin Selection bit
For 8 Pin Devices (PIC12F/LF1822):
0 = TX/CK function is on RA0
1 = TX/CK function is on RA4
For 14 Pin Devices (PIC16F/LF1823):
0 = TX/CK function is on RC4
1 = TX/CK function is on RA0
bit 1 P1BSEL: Pin Selection bit
For 8 Pin Devices (PIC12F/LF1822):
0 = P1B function is on RA0
1 = P1B function is on RA4
For 14 Pin Devices (PIC16F/LF1823):
P1B function is always on RC4
bit 0 CCP1SEL: Pin Selection bit
For 8 Pin Devices (PIC12F/LF1822):
0 = CCP1/P1A function is on RA2
1 = CCP1/P1A function is on RA5
For 14 Pin Devices (PIC16F/LF1823):
CCP1/P1A function is always on RC5
2010 Microchip Technology Inc. Preliminary DS41413A-page 119
PIC12F/LF1822/16F/LF1823
12.2 PORTA Registers
PORTA is a 6-bit wide, bidirectional port. The
corresponding data direction register is TRISA
(Register 12-3). Setting a TRISA bit (= 1) will make the
corresponding PORTA pin an input (i.e., disable the
output driver). Clearing a TRISA bit (= 0) will make the
corresponding PORTA pin an output (i.e., enables
output driver and puts the contents of the output latch
on the selected pin). The exception is RA3, which is
input only and its TRIS bit will always read as ‘1’.
Example 12-1 shows how to initialize PORTA.
Reading the PORTA register (Register 12-2) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then
written to the PORT data latch (LATA).
The TRISA register (Register 12-3) controls the
PORTA pin output drivers, even when they are being
used as analog inputs. The user should ensure the bits
in the TRISA register are maintained set when using
them as analog inputs. I/O pins configured as analog
input always read ‘0’.
12.2.1 ANSELA REGISTER
The ANSELA register (Register 12-5) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELA bit high will cause all
digital reads on the pin to be read as ‘0’ and allow
analog functions on the pin to operate correctly.
The state of the ANSELA bits has no affect on digital
output functions. A pin with TRIS clear and ANSEL set
will still operate as a digital output, but the Input mode
will be analog. This can cause unexpected behavior
when executing read-modify-write instructions on the
affected port.
EXAMPLE 12-1: INITIALIZING PORTA
Note: The ANSELA register must be initialized to
configure an analog channel as a digital
input. Pins configured as analog inputs will
read ‘0’.
BANKSEL PORTA ;
CLRF PORTA ;Init PORTA
BANKSEL LATA ;Data Latch
CLRF LATA ;
BANKSEL ANSELA ;
CLRF ANSELA ;digital I/O
BANKSEL TRISA ;
MOVLW B'00111000' ;Set RA<5:3> as inputs
MOVWF TRISA ;and set RA<2:0> as
;outputs
PIC12F/LF1822/16F/LF1823
DS41413A-page 120 Preliminary 2010 Microchip Technology Inc.
12.2.2 PORTA FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTA pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are briefly described here. For additional information,
refer to the appropriate section in this data sheet.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the lowest number in
the following lists.
Analog input functions, such as ADC, comparator and
CapSense inputs, are not shown in the priority lists.
These inputs are active when the I/O pin is set for
Analog mode using the ANSELx registers. Digital
output functions may control the pin when it is in Analog
mode with the priority shown below.
RA0
1. ICSPDAT
2. ICDDAT
3. DACOUT (DAC)
4. MDOUT (PIC12F/LF1822 only)
5. TX/CK (EUSART)
6. SDO (PIC12F/LF1822 only)
7. P1B (PIC12F/LF1822 only)
RA1
1. ICSPCLK
2. ICDCLK
3. SCL (PIC12F/LF1822 only)
4. RX/DT (EUSART)
5. SCK (PIC12F/LF1822 only)
RA2
1. SRQ
2. C1OUT (Comparator)
3. SDA (PIC12F/LF1822 only)
4. CCP1/P1A (PIC12F/LF1822 only)
RA3
No output priorities. Input only pin.
RA4
1. OSC2
2. CLKOUT
3. T1OSO
4. CLKR
5. TX/CK (PIC12F/LF1822 only)
6. SDO
7. P1B (PIC12F/LF1822 only)
RA5
1. OSC1
2. T1OSI (Timer1 Oscillator)
3. SRNQ (PIC12F/LF1822 only)
4. RX/DT (PIC12F/LF1822 only)
5. CCP1/P1A (PIC12F/LF1822 only)
2010 Microchip Technology Inc. Preliminary DS41413A-page 121
PIC12F/LF1822/16F/LF1823
REGISTER 12-2: PORTA: PORTA REGISTER
U-0 U-0 R/W-x/x R/W-x/x R-x/x R/W-x/x R/W-x/x R/W-x/x
—— RA5 RA4 RA3 RA2 RA1 RA0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0
bit 5-0 RA<5:0>: PORTA I/O Value bits(1)
1 = Port pin is > VIH
0 = Port pin is < VIL
Note 1: Writes to PORTA are actually written to corresponding LATA register. Reads from PORTA register is return
of actual I/O pin values.
REGISTER 12-3: TRISA: PORTA TRI-STATE REGISTER
U-0 U-0 R/W-1/1 R/W-1/1 R-1/1 R/W-1/1 R/W-1/1 R/W-1/1
—— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0
bit 5-4 TRISA<5:4>: PORTA Tri-State Control bits
1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output
bit 3 TRISA3: RA3 Port Tri-State Control bit
This bit is always ‘1’ as RA3 is an input only
bit 2-0 TRISA<2:0>: PORTA Tri-State Control bits
1 = PORTA pin configured as an input (tri-stated)
0 = PORTA pin configured as an output
PIC12F/LF1822/16F/LF1823
DS41413A-page 122 Preliminary 2010 Microchip Technology Inc.
REGISTER 12-4: LATA: PORTA DATA LATCH REGISTER
U-0 U-0 R/W-x/u R/W-x/u U-0 R/W-x/u R/W-x/u R/W-x/u
——LATA5LATA4— LATA2 LATA1 LATA0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0
bit 5-4 LATA<5:4>: RA<5:4> Output Latch Value bits(1)
bit 3 Unimplemented: Read as ‘0
bit 2-0 LATA<2:0>: RA<2:0> Output Latch Value bits(1)
Note 1: Writes to PORTA are actually written to corresponding LATA register. Reads from PORTA register is return
of actual I/O pin values.
REGISTER 12-5: ANSELA: PORTA ANALOG SELECT REGISTER
U-0 U-0 U-0 R/W-1/1 U-0 R/W-1/1 R/W-1/1 R/W-1/1
— — — ANSA4 — ANSA2 ANSA1 ANSA0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-5 Unimplemented: Read as ‘0’
bit 4 ANSA4: Analog Select between Analog or Digital Function on pins RA4, respectively
0 = Digital I/O. Pin is assigned to port or digital special function.
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
bit 3 Unimplemented: Read as ‘0’
bit 2-0 ANSA<2:0>: Analog Select between Analog or Digital Function on pins RA<2:0>, respectively
0 = Digital I/O. Pin is assigned to port or digital special function.
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
Note 1: When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to
allow external control of the voltage on the pin.
2010 Microchip Technology Inc. Preliminary DS41413A-page 123
PIC12F/LF1822/16F/LF1823
TABLE 12-1: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
TABLE 12-2: SUMMARY OF CONFIGURATION WORD WITH PORTA
REGISTER 12-6: WPUA: WEAK PULL-UP PORTA REGISTER
U-0 U-0 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1
—— WPUA5 WPUA4 WPUA3 WPUA2 WPUA1 WPUA0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 WPUB<5:0>: Weak Pull-up Register bits
1 = Pull-up enabled
0 = Pull-up disabled
Note 1: Global WPUEN bit of the OPTION register must be cleared for individual pull-ups to be enabled.
2: The weak pull-up device is automatically disabled if the pin is in configured as an output.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA ———ANSA4 — ANSA2 ANSA1 ANSA0 122
APFCON RXDTSEL SDOSEL SSSEL --- T1GSEL TXCKSEL P1BSEL CCP1SEL 118
LATA ——LATA5LATA4—LATA2LATA1LATA0
122
OPTION_REG WPUEN INTEDG TMR0CS TMR0SE PSA PS<2:0> 171
PORTA —— RA5 RA4 RA3 RA2 RA1 RA0 121
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
WPUA —— WPUA5 WPUA4 WPUA3 WPUA2 WPUA1 WPUA0 123
Legend: x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.
Note 1: PIC12F1822/16F1823 only.
2: PIC16F/LF1823 only.
Name Bits Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 Bit 10/2 Bit 9/1 Bit 8/0 Register
on Page
CONFIG1 13:8 — — FCMEN IESO CLKOUTEN BOREN<1:0> CPD 50
7:0 CP MCLRE PWRTE WDTE<1:0> FOSC<2:0>
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by PORTA.
Note 1: PIC12F1822/16F1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 124 Preliminary 2010 Microchip Technology Inc.
12.3 PORTC Registers
(PIC16F/LF1823 only)
PORTC is a 6-bit wide, bidirectional port. The
corresponding data direction register is TRISC
(Register 12-8). Setting a TRISC bit (= 1) will make the
corresponding PORTC pin an input (i.e., put the
corresponding output driver in a High-Impedance mode).
Clearing a TRISC bit (= 0) will make the corresponding
PORTC pin an output (i.e., enable the output driver and
put the contents of the output latch on the selected pin).
Example 12-2 shows how to initialize PORTC.
Reading the PORTC register (Register 12-7) reads the
status of the pins, whereas writing to it will write to the
PORT latch. All write operations are read-modify-write
operations. Therefore, a write to a port implies that the
port pins are read, this value is modified and then written
to the PORT data latch (LATC).
The TRISC register (Register 12-8) controls the PORTC
pin output drivers, even when they are being used as
analog inputs. The user should ensure the bits in the
TRISC register are maintained set when using them as
analog inputs. I/O pins configured as analog input always
read ‘0’.
12.3.1 ANSELC REGISTER
The ANSELC register (Register 12-10) is used to
configure the Input mode of an I/O pin to analog.
Setting the appropriate ANSELC bit high will cause all
digital reads on the pin to be read as ‘0’ and allow
analog functions on the pin to operate correctly.
The state of the ANSELC bits has no affect on digital out-
put functions. A pin with TRIS clear and ANSELC set will
still operate as a digital output, but the Input mode will be
analog. This can cause unexpected behavior when exe-
cuting read-modify-write instructions on the affected
port.
EXAMPLE 12-2: INITIALIZING PORTC
12.3.2 PORTC FUNCTIONS AND OUTPUT
PRIORITIES
Each PORTC pin is multiplexed with other functions. The
pins, their combined functions and their output priorities
are briefly described here. For additional information,
refer to the appropriate section in this data sheet.
When multiple outputs are enabled, the actual pin
control goes to the peripheral with the lowest number in
the following lists.
Analog input and some digital input functions are not
included in the list below. These input functions can
remain active when the pin is configured as an output.
Certain digital input functions override other port
functions and are included in the priority list.
RC0
1. SCL (MSSP)
2. SCK (MSSP)
RC1
1. SDA (MSSP)
RC2
1. SDO (MSSP)
2. P1D
RC3
1. P1C
RC4
1. MDOUT
2. SRNQ
3. C2OUT
4. TX/CK
5. P1B
RC5
1. RX/DT
2. CCP1/P1A
Note: The ANSELC register must be initialized
to configure an analog channel as a digital
input. Pins configured as analog inputs will
read ‘0’.
BANKSEL PORTC ;
CLRF PORTC ;Init PORTC
BANKSEL LATC ;Data Latch
CLRF LATC ;
BANKSEL ANSELC
CLRF ANSELC ;Make RC<5:0> digital
BANKSEL TRISB ;
MOVLW B’00110000’;Set RC<5:4> as inputs
;and RC<3:0> as outputs
MOVWF TRISC ;
2010 Microchip Technology Inc. Preliminary DS41413A-page 125
PIC12F/LF1822/16F/LF1823
REGISTER 12-7: PORTC: PORTC REGISTER
U-0 U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
—— RC5 RC4 RC3 RC2 RC1 RC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 RC<5:0>: PORTC General Purpose I/O Pin bits
1 = Port pin is > VIH
0 = Port pin is < VIL
REGISTER 12-8: TRISC: PORTC TRI-STATE REGISTER
U-0 U-0 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1
—— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 TRISC<5:0>: PORTC Tri-State Control bits
1 = PORTC pin configured as an input (tri-stated)
0 = PORTC pin configured as an output
REGISTER 12-9: LATC: PORTC DATA LATCH REGISTER
U-0 U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
—— LATC5 LATC4 LATC3 LATC2 LATC1 LATC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 LATC<5:0>: PORTC Output Latch Value bits(1)
Note 1: Writes to PORTC are actually written to corresponding LATC register. Reads from PORTC register is
return of actual I/O pin values.
PIC12F/LF1822/16F/LF1823
DS41413A-page 126 Preliminary 2010 Microchip Technology Inc.
TABLE 12-3: SUMMARY OF REGISTERS ASSOCIATED WITH PORTC(1)
REGISTER 12-10: ANSELC: PORTC ANALOG SELECT REGISTER
U-0 U-0 U-0 U-0 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1
— — — — ANSC3 ANSC2 ANSC1 ANSC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-4 Unimplemented: Read as ‘0’
bit 3-0 ANSC<3:0>: Analog Select between Analog or Digital Function on pins RC<3:0>, respectively
0 = Digital I/O. Pin is assigned to port or digital special function.
1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled.
Note 1: When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to
allow external control of the voltage on the pin.
REGISTER 12-11: WPUC: WEAK PULL-UP PORTC REGISTER
U-0 U-0 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1
—— WPUC5 WPUC4 WPUC3 WPUC2 WPUC1 WPUC0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 WPUC<5:0>: Weak Pull-up Register bits
1 = Pull-up enabled
0 = Pull-up disabled
Note 1: Global WPUEN bit of the OPTION register must be cleared for individual pull-ups to be enabled.
2: The weak pull-up device is automatically disabled if the pin is in configured as an output.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELC ———— ANSC3 ANSC2 ANSC1 ANSC0 126
LATC —— LATC5 LATC4 LATC3 LATC2 LATC1 LATC0 125
OPTION_REG WPUEN INTEDG TMR0CS TMR0SE PSA PS<2:0> 171
PORTC —— RC5 RC4 RC3 RC2 RC1 RC0 125
TRISC —— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
WPUC —— WPUC5 WPUC4 WPUC3 WPUC2 WPUC1 WPUC0 126
Legend: x = unknown, u = unchanged, - = unimplemented locations read as ‘0’. Shaded cells are not used by PORTC.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 127
PIC12F/LF1822/16F/LF1823
13.0 INTERRUPT-ON-CHANGE
The PORTA pins can be configured to operate as
Interrupt-On-Change (IOC) pins. An interrupt can be
generated by detecting a signal that has either a rising
edge or a falling edge. Any individual PORTA pin, or
combination of PORTA pins, can be configured to
generate an interrupt. The interrupt-on-change module
has the following features:
• Interrupt-on-Change enable (Master Switch)
• Individual pin configuration
• Rising and falling edge detection
• Individual pin interrupt flags
Figure 13-1 is a block diagram of the IOC module.
13.1 Enabling the Module
To allow individual PORTA pins to generate an interrupt,
the IOCIE bit of the INTCON register must be set. If the
IOCIE bit is disabled, the edge detection on the pin will
still occur, but an interrupt will not be generated.
13.2 Individual Pin Configuration
For each PORTA pin, a rising edge detector and a falling
edge detector are present. To enable a pin to detect a
rising edge, the associated IOCAPx bit of the IOCAP
register is set. To enable a pin to detect a falling edge,
the associated IOCANx bit of the IOCAN register is set.
A pin can be configured to detect rising and falling
edges simultaneously by setting both the IOCAPx bit
and the IOCANx bit of the IOCAP and IOCAN registers,
respectively.
13.3 Interrupt Flags
The IOCAFx bits located in the IOCAF register are
status flags that correspond to the Interrupt-on-change
pins of PORTA. If an expected edge is detected on an
appropriately enabled pin, then the status flag for that pin
will be set, and an interrupt will be generated if the IOCIE
bit is set. The IOCIF bit of the INTCON register reflects
the status of all IOCAFx bits.
13.4 Clearing Interrupt Flags
The individual status flags, (IOCAFx bits), can be
cleared by resetting them to zero. If another edge is
detected during this clearing operation, the associated
status flag will be set at the end of the sequence,
regardless of the value actually being written.
In order to ensure that no detected edge is lost while
clearing flags, only AND operations masking out known
changed bits should be performed. The following
sequence is an example of what should be performed.
EXAMPLE 13-1:
13.5 Operation in Sleep
The interrupt-on-change interrupt sequence will wake
the device from Sleep mode, if the IOCIE bit is set.
If an edge is detected while in Sleep mode, the IOCAF
register will be updated prior to the first instruction
executed out of Sleep.
FIGURE 13-1: INTERRUPT-ON-CHANGE BLOCK DIAGRAM
MOVLW 0xff
XORWF IOCAF, W
ANDWF IOCAF, F
RAx
From all other IOCAFx
individual pin detectors
DQ
CK
R
DQ
CK
R
IOCANx
IOCAPx
Q2 Clock Cycle
IOCIE
IOC Interrupt to
CPU Core
IOCAFx
PIC12F/LF1822/16F/LF1823
DS41413A-page 128 Preliminary 2010 Microchip Technology Inc.
REGISTER 13-1: IOCAP: INTERRUPT-ON-CHANGE PORTA POSITIVE EDGE REGISTER
U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
—— IOCAP5 IOCAP4 IOCAP3 IOCAP2 IOCAP1 IOCAP0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 IOCAP<5:0>: Interrupt-on-Change PORTA Positive Edge Enable bits
1 = Interrupt-on-Change enabled on the pin for a positive going edge. Associated Status bit and interrupt
flag will be set upon detecting an edge.
0 = Interrupt-on-Change disabled for the associated pin.
REGISTER 13-2: IOCAN: INTERRUPT-ON-CHANGE PORTA NEGATIVE EDGE REGISTER
U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
—— IOCAN5 IOCAN4 IOCAN3 IOCAN2 IOCAN1 IOCAN0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 IOCAN<5:0>: Interrupt-on-Change PORTA Negative Edge Enable bits
1 = Interrupt-on-Change enabled on the pin for a negative going edge. Associated Status bit and interrupt
flag will be set upon detecting an edge.
0 = Interrupt-on-Change disabled for the associated pin.
REGISTER 13-3: IOCAF: INTERRUPT-ON-CHANGE PORTA FLAG REGISTER
U-0 U-0 R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0
—— IOCAF5 IOCAF4 IOCAF3 IOCAF2 IOCAF1 IOCAF0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared HS - Bit is set in hardware
bit 7-6 Unimplemented: Read as ‘0’
bit 5-0 IOCAF<5:0>: Interrupt-on-Change PORTA Flag bits
1 = An enabled change was detected on the associated pin.
Set when IOCAPx = 1 and a rising edge was detected on RAx, or when IOCANx = 1 and a falling edge
was detected on RAx.
0 = No change was detected, or the user cleared the detected change.
2010 Microchip Technology Inc. Preliminary DS41413A-page 129
PIC12F/LF1822/16F/LF1823
TABLE 13-1: SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPT-ON-CHANGE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA — — — ANSA4 — ANSA2 ANSA1 ANSA0 122
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
IOCAF — — IOCAF5 IOCAF4 IOCAF3 IOCAF2 IOCAF1 IOCAF0 128
IOCAN — — IOCAN5 IOCAN4 IOCAN3 IOCAN2 IOCAN1 IOCAN0 128
IOCAP — — IOCAP5 IOCAP4 IOCAP3 IOCAP2 IOCAP1 IOCAP0 128
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by Interrupt-on-Change.
PIC12F/LF1822/16F/LF1823
DS41413A-page 130 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 131
PIC12F/LF1822/16F/LF1823
14.0 FIXED VOLTAGE REFERENCE
(FVR)
The Fixed Voltage Reference, or FVR, is a stable
voltage reference, independent of VDD, with 1.024V,
2.048V or 4.096V selectable output levels. The output
of the FVR can be configured to supply a reference
voltage to the following:
• ADC input channel
• ADC positive reference
• Comparator positive input
• Digital-to-Analog Converter (DAC)
The FVR can be enabled by setting the FVREN bit of
the FVRCON register.
14.1 Independent Gain Amplifiers
The output of the FVR supplied to the ADC,
Comparators, and DAC is routed through two
independent programmable gain amplifiers. Each
amplifier can be configured to amplify the reference
voltage by 1x, 2x or 4x, to produce the three possible
voltage levels.
The ADFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the ADC module. Refer-
ence Section 15.0 “Analog-to-Digital Converter
(ADC) Module” for additional information.
The CDAFVR<1:0> bits of the FVRCON register are
used to enable and configure the gain amplifier settings
for the reference supplied to the DAC and comparator
module. Reference Section 16.0 “Digital-to-Analog
Converter (DAC) Module” and Section 18.0 “Com-
parator Module” for additional information.
14.2 FVR Stabilization Period
When the Fixed Voltage Reference module is enabled, it
requires time for the reference and amplifier circuits to
stabilize. Once the circuits stabilize and are ready for use,
the FVRRDY bit of the FVRCON register will be set. See
Section 29.0 “Electrical Specifications” for the
minimum delay requirement.
FIGURE 14-1: VOLTAGE REFERENCE BLOCK DIAGRAM
ADFVR<1:0>
CDAFVR<1:0>
X1
X2
X4
X1
X2
X4
2
2
FVR BUFFER1
(To ADC Module)
FVR BUFFER2
(To Comparators, DAC)
+
_
FVREN
FVRRDY
1.024V Fixed
Reference
PIC12F/LF1822/16F/LF1823
DS41413A-page 132 Preliminary 2010 Microchip Technology Inc.
TABLE 14-1: SUMMARY OF REGISTERS ASSOCIATED WITH THE FIXED VOLTAGE REFERENCE
REGISTER 14-1: FVRCON: FIXED VOLTAGE REFERENCE CONTROL REGISTER
R/W-0/0 R-q/q R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
FVREN FVRRDY(1) Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition
bit 7 FVREN: Fixed Voltage Reference Enable bit
0 = Fixed Voltage Reference is disabled
1 = Fixed Voltage Reference is enabled
bit 6 FVRRDY: Fixed Voltage Reference Ready Flag bit(1)
0 = Fixed Voltage Reference output is not ready or not enabled
1 = Fixed Voltage Reference output is ready for use
bit 5-4 Reserved: Read as ‘0’. Maintain these bits clear.
bit 3-2 CDAFVR<1:0>: Comparator and DAC Fixed Voltage Reference Selection bits
00 = Comparator and DAC Fixed Voltage Reference Peripheral output is off
01 = Comparator and DAC Fixed Voltage Reference Peripheral output is 1x (1.024V)
10 = Comparator and DAC Fixed Voltage Reference Peripheral output is 2x (2.048V)(2)
11 = Comparator and DAC Fixed Voltage Reference Peripheral output is 4x (4.096V)(2)
bit 1-0 ADFVR<1:0>: ADC Fixed Voltage Reference Selection bits
00 = ADC Fixed Voltage Reference Peripheral output is off
01 = ADC Fixed Voltage Reference Peripheral output is 1x (1.024V)
10 = ADC Fixed Voltage Reference Peripheral output is 2x (2.048V)(2)
11 = ADC Fixed Voltage Reference Peripheral output is 4x (4.096V)(2)
Note 1: FVRRDY is always ‘1’ on devices with the LDO (PIC12F1822/16F1823).
2: Fixed Voltage Reference output cannot exceed VDD.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on page
FVRCON FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 132
Legend: Shaded cells are unused by the Fixed Voltage Reference module.
2010 Microchip Technology Inc. Preliminary DS41413A-page 133
PIC12F/LF1822/16F/LF1823
15.0 ANALOG-TO-DIGITAL
CONVERTER (ADC) MODULE
The Analog-to-Digital Converter (ADC) allows
conversion of an analog input signal to a 10-bit binary
representation of that signal. This device uses analog
inputs, which are multiplexed into a single sample and
hold circuit. The output of the sample and hold is
connected to the input of the converter. The converter
generates a 10-bit binary result via successive
approximation and stores the conversion result into the
ADC result registers (ADRESH:ADRESL register pair).
Figure 15-1 shows the block diagram of the ADC.
The ADC voltage reference is software selectable to be
either internally generated or externally supplied.
The ADC can generate an interrupt upon completion of
a conversion. This interrupt can be used to wake-up the
device from Sleep.
FIGURE 15-1: ADC BLOCK DIAGRAM
Note 1: When ADON = 0, all multiplexer inputs are disconnected.
2: Not available on PIC12F/LF1822.
DAC
VDD
VREF+ADPREF = 10
ADPREF = 00
ADPREF = 11
FVR Buffer1
ADON(1)
GO/DONE
VSS
ADC
00000
00001
00010
00011
00100
00101
00111
00110
11110
CHS<4:0>
AN0
AN1
AN2
AN4(2)
AN5(2)
AN6(2)
AN7(2)
AN3
11111
ADRESH ADRESL
10
16
ADFM 0 = Left Justify
1 = Right Justify
PIC12F/LF1822/16F/LF1823
DS41413A-page 134 Preliminary 2010 Microchip Technology Inc.
15.1 ADC Configuration
When configuring and using the ADC the following
functions must be considered:
• Port configuration
• Channel selection
• ADC voltage reference selection
• ADC conversion clock source
• Interrupt control
• Result formatting
15.1.1 PORT CONFIGURATION
The ADC can be used to convert both analog and
digital signals. When converting analog signals, the I/O
pin should be configured for analog by setting the
associated TRIS and ANSEL bits. Refer to
Section 12.0 “I/O Ports” for more information.
15.1.2 CHANNEL SELECTION
There are up to 10 channel selections available:
• AN<3:0> pins (PIC12F/LF1822 only)
• AN<7:0> pins (PIC16F/LF1823 only)
• DAC Output
• FVR (Fixed Voltage Reference) Output
Refer to Section 16.0 “Digital-to-Analog Converter
(DAC) Module” and Section 14.0 “Fixed Voltage
Reference (FVR)” for more information on these chan-
nel selections.
The CHS bits of the ADCON0 register determine which
channel is connected to the sample and hold circuit.
When changing channels, a delay is required before
starting the next conversion. Refer to Section 15.2
“ADC Operation” for more information.
15.1.3 ADC VOLTAGE REFERENCE
The ADPREF bits of the ADCON1 register provides
control of the positive voltage reference. The positive
voltage reference can be:
•V
REF+ pin
•VDD
•FVR
See Section 14.0 “Fixed Voltage Reference (FVR)”
for more details on the fixed voltage reference.
15.1.4 CONVERSION CLOCK
The source of the conversion clock is software select-
able via the ADCS bits of the ADCON1 register. There
are seven possible clock options:
•F
OSC/2
•FOSC/4
•FOSC/8
•F
OSC/16
•FOSC/32
•FOSC/64
•F
RC (dedicated internal oscillator)
The time to complete one bit conversion is defined as
TAD. One full 10-bit conversion requires 11.5 TAD peri-
ods as shown in Figure 15-2.
For correct conversion, the appropriate TAD specifica-
tion must be met. Refer to the A/D conversion require-
ments in Section 29.0 “Electrical Specifications” for
more information. Table 15-1 gives examples of appro-
priate ADC clock selections.
Note: Analog voltages on any pin that is defined
as a digital input may cause the input buf-
fer to conduct excess current.
Note: Unless using the FRC, any changes in the
system clock frequency will change the
ADC clock frequency, which may
adversely affect the ADC result.
2010 Microchip Technology Inc. Preliminary DS41413A-page 135
PIC12F/LF1822/16F/LF1823
TABLE 15-1: ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES
FIGURE 15-2: ANALOG-TO-DIGITAL CONVERSION TAD CYCLES
ADC Clock Period (TAD)Device Frequency (FOSC)
Device Frequency (FOSC)
ADC
Clock Source ADCS<2:0> 32 MHz 20 MHz 16 MHz 8 MHz 4 MHz 1 MHz
Fosc/2 000 62.5ns(2) 100 ns(2) 125 ns(2) 250 ns(2) 500 ns(2) 2.0 s
Fosc/4 100 125 ns(2) 200 ns(2) 250 ns(2) 500 ns(2) 1.0 s4.0 s
Fosc/8 001 0.5 s(2) 400 ns(2) 0.5 s(2) 1.0 s2.0 s8.0 s(3)
Fosc/16 101 800 ns 800 ns 1.0 s2.0 s4.0 s16.0 s(3)
Fosc/32 010 1.0 s1.6 s2.0 s4.0 s8.0 s(3) 32.0 s(3)
Fosc/64 110 2.0 s3.2 s4.0 s8.0 s(3) 16.0 s(3) 64.0 s(3)
FRC x11 1.0-6.0 s(1,4) 1.0-6.0 s(1,4) 1.0-6.0 s(1,4) 1.0-6.0 s(1,4) 1.0-6.0 s(1,4) 1.0-6.0 s(1,4)
Legend: Shaded cells are outside of recommended range.
Note 1: The FRC source has a typical TAD time of 1.6 s for VDD.
2: These values violate the minimum required TAD time.
3: For faster conversion times, the selection of another clock source is recommended.
4: When the device frequency is greater than 1 MHz, the FRC clock source is only recommended if the conversion will be
performed during Sleep.
5: The ADC clock period (TAD) and total ADC conversion time can be minimized when the ADC clock is derived from the
system clock FOSC. However, the FRC clock source must be used when conversions are to be performed with the
device in Sleep mode.
TAD1TAD2TAD3TAD4 TAD5TAD6 TAD7TAD8 TAD11
Set GO bit
Holding capacitor is disconnected from analog input (typically 100 ns)
TAD9 TAD10
TCY - TAD
ADRESH:ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
Conversion starts
b0
b9 b6 b5 b4 b3 b2 b1
b8 b7
On the following cycle:
PIC12F/LF1822/16F/LF1823
DS41413A-page 136 Preliminary 2010 Microchip Technology Inc.
15.1.5 INTERRUPTS
The ADC module allows for the ability to generate an
interrupt upon completion of an Analog-to-Digital
conversion. The ADC Interrupt Flag is the ADIF bit in
the PIR1 register. The ADC Interrupt Enable is the
ADIE bit in the PIE1 register. The ADIF bit must be
cleared in software.
This interrupt can be generated while the device is
operating or while in Sleep. If the device is in Sleep, the
interrupt will wake-up the device. Upon waking from
Sleep, the next instruction following the SLEEP instruc-
tion is always executed. If the user is attempting to
wake-up from Sleep and resume in-line code execu-
tion, the GIE and PEIE bits of the INTCON register
must be disabled. If the GIE and PEIE bits of the
INTCON register are enabled, execution will switch to
the Interrupt Service Routine.
Please refer to Section 8.0 “Interrupts” for more
information.
15.1.6 RESULT FORMATTING
The 10-bit A/D conversion result can be supplied in two
formats, left justified or right justified. The ADFM bit of
the ADCON1 register controls the output format.
Figure 15-3 shows the two output formats.
FIGURE 15-3: 10-BIT A/D CONVERSION RESULT FORMAT
Note 1: The ADIF bit is set at the completion of
every conversion, regardless of whether
or not the ADC interrupt is enabled.
2: The ADC operates during Sleep only
when the FRC oscillator is selected.
ADRESH ADRESL
(ADFM = 0)MSB LSB
bit 7 bit 0 bit 7 bit 0
10-bit A/D Result Unimplemented: Read as ‘0’
(ADFM = 1)MSB LSB
bit 7 bit 0 bit 7 bit 0
Unimplemented: Read as ‘0’ 10-bit A/D Result
2010 Microchip Technology Inc. Preliminary DS41413A-page 137
PIC12F/LF1822/16F/LF1823
15.2 ADC Operation
15.2.1 STARTING A CONVERSION
To enable the ADC module, the ADON bit of the
ADCON0 register must be set to a ‘1’. Setting the GO/
DONE bit of the ADCON0 register to a ‘1’ will start the
Analog-to-Digital conversion.
15.2.2 COMPLETION OF A CONVERSION
When the conversion is complete, the ADC module will:
• Clear the GO/DONE bit
• Set the ADIF Interrupt Flag bit
• Update the ADRESH and ADRESL registers with
new conversion result
15.2.3 TERMINATING A CONVERSION
If a conversion must be terminated before completion,
the GO/DONE bit can be cleared in software. The
ADRESH and ADRESL registers will be updated with
the partially complete Analog-to-Digital conversion
sample. Incomplete bits will match the last bit
converted.
15.2.4 ADC OPERATION DURING SLEEP
The ADC module can operate during Sleep. This
requires the ADC clock source to be set to the FRC
option. When the FRC clock source is selected, the
ADC waits one additional instruction before starting the
conversion. This allows the SLEEP instruction to be
executed, which can reduce system noise during the
conversion. If the ADC interrupt is enabled, the device
will wake-up from Sleep when the conversion
completes. If the ADC interrupt is disabled, the ADC
module is turned off after the conversion completes,
although the ADON bit remains set.
When the ADC clock source is something other than
FRC, a SLEEP instruction causes the present conver-
sion to be aborted and the ADC module is turned off,
although the ADON bit remains set.
15.2.5 SPECIAL EVENT TRIGGER
The Special Event Trigger of the CCP1 module allows
periodic ADC measurements without software inter-
vention. When this trigger occurs, the GO/DONE bit is
set by hardware and the Timer1 counter resets to zero.
Using the Special Event Trigger does not assure proper
ADC timing. It is the user’s responsibility to ensure that
the ADC timing requirements are met.
Refer to Section 23.0 “Capture/Compare/PWM Mod-
ules” for more information.
Note: The GO/DONE bit should not be set in the
same instruction that turns on the ADC.
Refer to Section 15.2.6 “A/D Conver-
sion Procedure”.
Note: A device Reset forces all registers to their
Reset state. Thus, the ADC module is
turned off and any pending conversion is
terminated.
PIC12F/LF1822/16F/LF1823
DS41413A-page 138 Preliminary 2010 Microchip Technology Inc.
15.2.6 A/D CONVERSION PROCEDURE
This is an example procedure for using the ADC to
perform an Analog-to-Digital conversion:
1. Configure Port:
• Disable pin output driver (Refer to the TRIS
register)
• Configure pin as analog (Refer to the ANSEL
register)
2. Configure the ADC module:
• Select ADC conversion clock
• Configure voltage reference
• Select ADC input channel
• Turn on ADC module
3. Configure ADC interrupt (optional):
• Clear ADC interrupt flag
• Enable ADC interrupt
• Enable peripheral interrupt
• Enable global interrupt(1)
4. Wait the required acquisition time(2).
5. Start conversion by setting the GO/DONE bit.
6. Wait for ADC conversion to complete by one of
the following:
• Polling the GO/DONE bit
• Waiting for the ADC interrupt (interrupts
enabled)
7. Read ADC Result.
8. Clear the ADC interrupt flag (required if interrupt
is enabled).
EXAMPLE 15-1: A/D CONVERSION
Note 1: The global interrupt can be disabled if the
user is attempting to wake-up from Sleep
and resume in-line code execution.
2: Refer to Section 15.3 “A/D Acquisition
Requirements”.
;This code block configures the ADC
;for polling, Vdd and Vss references, Frc
;clock and AN0 input.
;
;Conversion start & polling for completion
; are included.
;
BANKSEL ADCON1 ;
MOVLW B’11110000’ ;Right justify, Frc
;clock
MOVWF ADCON1 ;Vdd and Vss Vref
BANKSEL TRISA ;
BSF TRISA,0 ;Set RA0 to input
BANKSEL ANSEL ;
BSF ANSEL,0 ;Set RA0 to analog
BANKSEL ADCON0 ;
MOVLW B’00000001’ ;Select channel AN0
MOVWF ADCON0 ;Turn ADC On
CALL SampleTime ;Acquisiton delay
BSF ADCON0,ADGO ;Start conversion
BTFSC ADCON0,ADGO ;Is conversion done?
GOTO $-1 ;No, test again
BANKSEL ADRESH ;
MOVF ADRESH,W ;Read upper 2 bits
MOVWF RESULTHI ;store in GPR space
BANKSEL ADRESL ;
MOVF ADRESL,W ;Read lower 8 bits
MOVWF RESULTLO ;Store in GPR space
2010 Microchip Technology Inc. Preliminary DS41413A-page 139
PIC12F/LF1822/16F/LF1823
15.2.7 ADC REGISTER DEFINITIONS
The following registers are used to control the
operation of the ADC.
REGISTER 15-1: ADCON0: A/D CONTROL REGISTER 0
U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
— CHS4 CHS3 CHS2 CHS1 CHS0 GO/DONE ADON
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 Unimplemented: Read as ‘0’
bit 6-2 CHS<4:0>: Analog Channel Select bits
00000 =AN0
00001 =AN1
00010 =AN2
00011 =AN3
00100 =AN4
(1)
00101 =AN5
(1)
00110 =AN6
(1)
00111 =AN7
(1)
01001 = Reserved. No channel connected.
•
•
•
11101 = Reserved. No channel connected.
11110 = DAC output(2)
11111 = FVR (Fixed Voltage Reference) Buffer 1 Output(3)
bit 1 GO/DONE: A/D Conversion Status bit
1 = A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle.
This bit is automatically cleared by hardware when the A/D conversion has completed.
0 = A/D conversion completed/not in progress
bit 0 ADON: ADC Enable bit
1 = ADC is enabled
0 = ADC is disabled and consumes no operating current
Note 1: PIC16F/LF1823 only. For PIC12F/LF1822 it is “Reserved. No channel connected”.
2: See Section 16.0 “Digital-to-Analog Converter (DAC) Module” for more information.
3: See Section 14.0 “Fixed Voltage Reference (FVR)” for more information.
PIC12F/LF1822/16F/LF1823
DS41413A-page 140 Preliminary 2010 Microchip Technology Inc.
REGISTER 15-2: ADCON1: A/D CONTROL REGISTER 1
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 U-0 R/W-0/0 R/W-0/0
ADFM ADCS2 ADCS1 ADCS0 —— ADPREF1 ADPREF0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 ADFM: A/D Result Format Select bit
1 = Right justified. Six Most Significant bits of ADRESH are set to ‘0’ when the conversion result is
loaded.
0 = Left justified. Six Least Significant bits of ADRESL are set to ‘0’ when the conversion result is
loaded.
bit 6-4 ADCS<2:0>: A/D Conversion Clock Select bits
000 =F
OSC/2
001 =F
OSC/8
010 =F
OSC/32
011 =F
RC (clock supplied from a dedicated RC oscillator)
100 =F
OSC/4
101 =F
OSC/16
110 =F
OSC/64
111 =F
RC (clock supplied from a dedicated RC oscillator)
bit 3-2 Unimplemented: Read as ‘0’
bit 1-0 ADPREF<1:0>: A/D Positive Voltage Reference Configuration bits
00 =VREF+ is connected to AVDD
01 = Reserved
10 =V
REF+ is connected to external VREF+
11 =V
REF+ is connected to internal fixed voltage reference
2010 Microchip Technology Inc. Preliminary DS41413A-page 141
PIC12F/LF1822/16F/LF1823
REGISTER 15-3: ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 0
R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
ADRES9 ADRES8 ADRES7 ADRES6 ADRES5 ADRES4 ADRES3 ADRES2
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-0 ADRES<9:2>: ADC Result Register bits
Upper 8 bits of 10-bit conversion result
REGISTER 15-4: ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 0
R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
ADRES1 ADRES0 — — — — — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 ADRES<1:0>: ADC Result Register bits
Lower 2 bits of 10-bit conversion result
bit 5-0 Reserved: Do not use.
PIC12F/LF1822/16F/LF1823
DS41413A-page 142 Preliminary 2010 Microchip Technology Inc.
REGISTER 15-5: ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 1
R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
— — — — — — ADRES9 ADRES8
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-2 Reserved: Do not use.
bit 1-0 ADRES<9:8>: ADC Result Register bits
Upper 2 bits of 10-bit conversion result
REGISTER 15-6: ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 1
R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u
ADRES7 ADRES6 ADRES5 ADRES4 ADRES3 ADRES2 ADRES1 ADRES0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-0 ADRES<7:0>: ADC Result Register bits
Lower 8 bits of 10-bit conversion result
2010 Microchip Technology Inc. Preliminary DS41413A-page 143
PIC12F/LF1822/16F/LF1823
15.3 A/D Acquisition Requirements
For the ADC to meet its specified accuracy, the charge
holding capacitor (CHOLD) must be allowed to fully
charge to the input channel voltage level. The Analog
Input model is shown in Figure 15-4. The source
impedance (RS) and the internal sampling switch (RSS)
impedance directly affect the time required to charge
the capacitor CHOLD. The sampling switch (RSS)
impedance varies over the device voltage (VDD), refer
to Figure 15-4. The maximum recommended
impedance for analog sources is 10 k. As the
source impedance is decreased, the acquisition time
may be decreased. After the analog input channel is
selected (or changed), an A/D acquisition must be
done before the conversion can be started. To calculate
the minimum acquisition time, Equation 15-1 may be
used. This equation assumes that 1/2 LSb error is used
(1,024 steps for the ADC). The 1/2 LSb error is the
maximum error allowed for the ADC to meet its
specified resolution.
EQUATION 15-1: ACQUISITION TIME EXAMPLE
TACQ Amplifier Settling Time Hold Capacitor Charging Time Temperature Coefficient++=
TAMP TCTCOFF++=
2µs TCTemperature - 25°C0.05µs/°C++=
TCCHOLD RIC RSS RS++ ln(1/511)–=
10pF 1k
7k
10k
++– ln(0.001957)=
1.12=µs
VAPPLIED 1e
Tc–
RC
---------
–
VAPPLIED 11
2n1+
1–
--------------------------–
=
VAPPLIED 11
2n1+
1–
--------------------------
–
VCHOLD=
VAPPLIED 1e
TC–
RC
----------
–
VCHOLD=
;[1] VCHOLD charged to within 1/2 lsb
;[2] VCHOLD charge response to VAPPLIED
;combining [1] and [2]
The value for TC can be approximated with the following equations:
Solving for TC:
Temperature 50°C and external impedance of 10k
5.0V VDD=
Assumptions:
Note: Where n = number of bits of the ADC.
Therefore:
4.42µs=
TACQ = 2µs + 1.12µs + [(50°C - 25°C) (0.05µs/°C)]
Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out.
2: The charge holding capacitor (CHOLD) is not discharged after each conversion.
3: The maximum recommended impedance for analog sources is 10 k. This is required to meet the pin
leakage specification.
PIC12F/LF1822/16F/LF1823
DS41413A-page 144 Preliminary 2010 Microchip Technology Inc.
FIGURE 15-4: ANALOG INPUT MODEL
FIGURE 15-5: ADC TRANSFER FUNCTION
CPIN
VA
Rs ANx
5 pF
VDD
VT 0.6V
VT 0.6V I LEAKAGE(1)
RIC 1k
Sampling
Switch
SS Rss
CHOLD = 10 pF
VSS/VREF-
6V
Sampling Switch
5V
4V
3V
2V
567891011
(k)
VDD
Legend:
CPIN
VT
I LEAKAGE
RIC
SS
CHOLD
= Input Capacitance
= Threshold Voltage
= Leakage current at the pin due to
= Interconnect Resistance
= Sampling Switch
= Sample/Hold Capacitance
various junctions
RSS
Note 1: Refer to Section 29.0 “Electrical Specifications”.
RSS = Resistance of Sampling Switch
FFh
FEh
ADC Output Code
FDh
FCh
04h
03h
02h
01h
00h
Full-Scale
FBh
1 LSB ideal
VSS Zero-Scale
Transition VREF
Transition
1 LSB ideal
Full-Scale Range
Analog Input Voltage
2010 Microchip Technology Inc. Preliminary DS41413A-page 145
PIC12F/LF1822/16F/LF1823
TABLE 15-2: SUMMARY OF REGISTERS ASSOCIATED WITH ADC
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ADCON0 — CHS4 CHS3 CHS2 CHS1 CHS0 GO/DONE ADON 139
ADCON1 ADFM ADCS2 ADCS1 ADCS0 —— ADPREF1 ADPREF0 140
ADRESH A/D Result Register High 141*
ADRESL A/D Result Register Low 141*
ANSELA ———ANSA4— ANSA2 ANSA1 ANSA0 122
ANSELC(1) ———— ANSC3 ANSC2 ANSC1 ANSC0 126
CCP1CON P1M1 P1M0 DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 221
DACCON0 DACEN DACLPS DACOE — DACPSS1 DACPSS0 — — 151
DACCON1 ——— DACR4 DACR3 DACR2 DACR1 DACR0 151
FVRCON FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 132
INTCON GIE PEIE TMR0IE INTE IOCE TMR0IF INTF IOCF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = unimplemented read as ‘0’. Shaded cells are not used for ADC module.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 146 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 147
PIC12F/LF1822/16F/LF1823
16.0 DIGITAL-TO-ANALOG
CONVERTER (DAC) MODULE
The Digital-to-Analog Converter supplies a variable
voltage reference, ratiometric with the input source,
with 32 selectable output levels.
The input of the DAC can be connected to:
•External V
REF pins
•VDD supply voltage
• FVR (Fixed Voltage Reference)
The output of the DAC can be configured to supply a
reference voltage to the following:
• Comparator positive input
• ADC input channel
•DACOUT pin
The Digital-to-Analog Converter (DAC) can be enabled
by setting the DACEN bit of the DACCON0 register.
16.1 Output Voltage Selection
The DAC has 32 voltage level ranges. The 32 levels
are set with the DACR<4:0> bits of the DACCON1
register.
The DAC output voltage is determined by the following
equations:
EQUATION 16-1: DAC OUTPUT VOLTAGE
16.2 Ratiometric Output Level
The DAC output value is derived using a resistor ladder
with each end of the ladder tied to a positive and
negative voltage reference input source. If the voltage
of either input source fluctuates, a similar fluctuation will
result in the DAC output value.
The value of the individual resistors within the ladder
can be found in Section 29.0 “Electrical
Specifications”.
16.3 Low-Power Voltage State
In order for the DAC module to consume the least
amount of power, one of the two voltage reference input
sources to the resistor ladder must be disconnected.
Either the positive voltage source, (VSRC+), or the
negative voltage source, (VSRC-) can be disabled.
The negative voltage source is disabled by setting the
DACLPS bit in the DACCON0 register. Clearing the
DACLPS bit in the DACCON0 register disables the
positive voltage source.
16.3.1 OUTPUT CLAMPED TO POSITIVE
VOLTAGE SOURCE
The DAC output voltage can be set to VSRC+ with the
least amount of power consumption by performing the
following:
• Clearing the DACEN bit in the DACCON0 register.
• Setting the DACLPS bit in the DACCON0 register.
• Configuring the DACPSS bits to the proper
positive source.
• Configuring the DACR<4:0> bits to ‘11111’ in the
DACCON1 register.
This is also the method used to output the voltage level
from the FVR to an output pin. See Section 16.4 “DAC
Voltage Reference Output” for more information.
Reference Figure 16-1 for output clamping examples.
16.3.2 OUTPUT CLAMPED TO NEGATIVE
VOLTAGE SOURCE
The DAC output voltage can be set to VSRC- with the
least amount of power consumption by performing the
following:
• Clearing the DACEN bit in the DACCON0 register.
• Clearing the DACLPS bit in the DACCON0 register.
• Configuring the DACNSS bits to the proper
negative source.
• Configuring the DACR<4:0> bits to ‘00000’ in the
DACCON1 register.
This allows the comparator to detect a zero-crossing
while not consuming additional current through the DAC
module.
Reference Figure 16-1 for output clamping examples.
VOUT VSOURCE+VSOURCE-–
DACR<4:0>
25
-------------------------------
=+ VSRC-
Note: VSOURCE+ can equal FVR Buffer 2, VDD or
VREF+. VSOURCE- can equal VSS or VREF-.
PIC12F/LF1822/16F/LF1823
DS41413A-page 148 Preliminary 2010 Microchip Technology Inc.
FIGURE 16-1: OUTPUT VOLTAGE CLAMPING EXAMPLES
R
R
R
DAC Voltage Ladder
(see Figure 16-2)
VSRC+
DACEN = 0
DACLPS = 1
DACR<4:0> = 11111
VSRC-
R
R
R
DAC Voltage Ladder
(see Figure 16-2)
VSRC+
DACEN = 0
DACLPS = 0
DACR<4:0> = 00000
VSRC-
Output Clamped to Positive Voltage Source Output Clamped to Positive Voltage Source
2010 Microchip Technology Inc. Preliminary DS41413A-page 149
PIC12F/LF1822/16F/LF1823
16.4 DAC Voltage Reference Output
The DAC can be output to the DACOUT pin by setting
the DACOE bit of the DACCON0 register to ‘1’. Selecting
the DAC reference voltage for output on the DACOUT
pin automatically overrides the digital output buffer and
digital input threshold detector functions of that pin.
Reading the DACOUT pin when it has been configured
for DAC reference voltage output will always return a ‘0’.
Due to the limited current drive capability, a buffer must
be used on the DAC voltage reference output for
external connections to DACOUT. Figure 16-3 shows
an example buffering technique.
FIGURE 16-2: DIGITAL-TO-ANALOG CONVERTER BLOCK DIAGRAM
32-to-1 MUX
DACR<4:0>
R
VREF-
R
R
R
R
R
R
32 DAC
DACOUT
5
(To Comparator, CSM and
ADC Modules)
DACOE
VDD
VREF+
DACPSS<1:0> 2
DACEN
Steps
Digital-to-Analog Converter (DAC)
FVR BUFFER2
R
VSRC-
VSRC+
VSS
DACLPS
PIC12F/LF1822/16F/LF1823
DS41413A-page 150 Preliminary 2010 Microchip Technology Inc.
FIGURE 16-3: VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
16.5 Operation During Sleep
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the DACCON0 register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
16.6 Effects of a Reset
A device Reset affects the following:
• DAC is disabled.
• DAC output voltage is removed from the
DACOUT pin.
• The DACR<4:0> range select bits are cleared.
DACOUT Buffered DAC Output
+
–
DAC
Module
Voltage
Reference
Output
Impedance
R
PIC® MCU
2010 Microchip Technology Inc. Preliminary DS41413A-page 151
PIC12F/LF1822/16F/LF1823
REGISTER 16-1: DACCON0: VOLTAGE REFERENCE CONTROL REGISTER 0
R/W-0/0 R/W-0/0 R/W-0/0 U-0 R/W-0/0 R/W-0/0 U-0 U-0
DACEN DACLPS DACOE — DACPSS<1:0> — —
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 DACEN: DAC Enable bit
1 = DAC is enabled
0 = DAC is disabled
bit 6 DACLPS: DAC Low-Power Voltage State Select bit
1 = DAC Positive reference source selected
0 = DAC Negative reference source selected
bit 5 DACOE: DAC Voltage Output Enable bit
1 = DAC voltage level is also an output on the DACOUT pin
0 = DAC voltage level is disconnected from the DACOUT pin
bit 4 Unimplemented: Read as ‘0’
bit 3-2 DACPSS<1:0>: DAC Positive Source Select bits
00 =V
DD
01 =VREF+
10 = FVR Buffer2 output
11 = Reserved, do not use
bit 1-0 Unimplemented: Read as ‘0’
REGISTER 16-2: DACCON1: VOLTAGE REFERENCE CONTROL REGISTER 1
U-0 U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
— — —DACR<4:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-5 Unimplemented: Read as ‘0’
bit 4-0 DACR<4:0>: DAC Voltage Output Select bits
VOUT = ((VSRC+) - (VSRC-))*(DACR<4:0>/(25)) + VSRC-
Note 1: The output select bits are always right justified to ensure that any number of bits can be used without
affecting the register layout.
PIC12F/LF1822/16F/LF1823
DS41413A-page 152 Preliminary 2010 Microchip Technology Inc.
TABLE 16-1: SUMMARY OF REGISTERS ASSOCIATED WITH THE DAC MODULE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on page
FVRCON FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 132
DACCON0 DACEN DACLPS DACOE — DACPSS1 DACPSS0 — — 151
DACCON1 — — — DACR4 DACR3 DACR2 DACR1 DACR0 151
Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the DAC module.
2010 Microchip Technology Inc. Preliminary DS41413A-page 153
PIC12F/LF1822/16F/LF1823
17.0 SR LATCH
The module consists of a single SR Latch with multiple
Set and Reset inputs as well as separate latch outputs.
The SR Latch module includes the following features:
• Programmable input selection
• SR Latch output is available externally
• Separate Q and Q outputs
• Firmware Set and Reset
The SR Latch can be used in a variety of analog appli-
cations, including oscillator circuits, one-shot circuit,
hysteretic controllers, and analog timing applications.
17.1 Latch Operation
The latch is a Set-Reset Latch that does not depend on
a clock source. Each of the Set and Reset inputs are
active-high. The latch can be Set or Reset by:
• Software control (SRPS and SRPR bits)
• Comparator C1 output (SYNCC1OUT)
• Comparator C2 output (SYNCC2OUT)
(PIC16F/LF1823 only)
•SRI pin
• Programmable clock (SRCLK)
The SRPS and the SRPR bits of the SRCON0 register
may be used to Set or Reset the SR Latch, respec-
tively. The latch is Reset-dominant. Therefore, if both
Set and Reset inputs are high, the latch will go to the
Reset state. Both the SRPS and SRPR bits are self
resetting which means that a single write to either of the
bits is all that is necessary to complete a latch Set or
Reset operation.
The output from Comparator C1 or C2 can be used as
the Set or Reset inputs of the SR Latch. The output of
either Comparator can be synchronized to the Timer1
clock source. See Section 18.0 “Comparator
Module” and Section 20.0 “Timer1 Module with
Gate Control” for more information.
An external source on the SRI pin can be used as the
Set or Reset inputs of the SR Latch.
An internal clock source is available that can periodically
set or reset the SR Latch. The SRCLK<2:0> bits in the
SRCON0 register are used to select the clock source
period. The SRSCKE and SRRCKE bits of the SRCON1
register enable the clock source to Set or Reset the SR
Latch, respectively.
17.2 Latch Output
The SRQEN and SRNQEN bits of the SRCON0 regis-
ter control the Q and Q latch outputs. Both of the SR
Latch outputs may be directly output to an I/O pin at the
same time.
The applicable TRIS bit of the corresponding port must
be cleared to enable the port pin output driver.
17.3 Effects of a Reset
Upon any device Reset, the SR Latch output is not ini-
tialized to a known state. The user’s firmware is
responsible for initializing the latch output before
enabling the output pins.
Note: Enabling both the Set and Reset inputs
from any one source at the same time may
result in indeterminate operation, as the
Reset dominance cannot be assured.
PIC12F/LF1822/16F/LF1823
DS41413A-page 154 Preliminary 2010 Microchip Technology Inc.
FIGURE 17-1: SR LATCH SIMPLIFIED BLOCK DIAGRAM
SRPS
S
R
Q
Q
Note 1: If R = 1 and S = 1 simultaneously, Q = 0, Q =1
2: Pulse generator causes a 1 Q-state pulse width.
3: Name denotes the connection point at the comparator output.
4: PIC16F/LF1823 only.
Pulse
Gen(2)
SR
Latch(1)
SRQEN
SRSPE
SRSC2E(4)
SRSCKE
SRCLK
SYNCC2OUT(3, 4)
SRSC1E
SYNCC1OUT(3)
SRPR Pulse
Gen(2)
SRRPE
SRRC2E(4)
SRRCKE
SRCLK
SYNCC2OUT(3, 4)
SRRC1E
SYNCC1OUT(3)
SRLEN
SRNQEN
SRLEN
SRQ
SRNQ
SRI
SRI
2010 Microchip Technology Inc. Preliminary DS41413A-page 155
PIC12F/LF1822/16F/LF1823
TABLE 17-1: SRCLK FREQUENCY TABLE
SRCLK Divider FOSC = 32 MHz FOSC = 20 MHz FOSC = 16 MHz FOSC = 4 MHz FOSC = 1 MHz
111 512 62.5 kHz 39.0 kHz 31.3 kHz 7.81 kHz 1.95 kHz
110 256 125 kHz 78.1 kHz 62.5 kHz 15.6 kHz 3.90 kHz
101 128 250 kHz 156 kHz 125 kHz 31.25 kHz 7.81 kHz
100 64 500 kHz 313 kHz 250 kHz 62.5 kHz 15.6 kHz
011 32 1 MHz 625 kHz 500 kHz 125 kHz 31.3 kHz
010 16 2 MHz 1.25 MHz 1 MHz 250 kHz 62.5 kHz
001 8 4 MHz 2.5 MHz 2 MHz 500 kHz 125 kHz
000 4 8 MHz 5 MHz 4 MHz 1 MHz 250 kHz
REGISTER 17-1: SRCON0: SR LATCH CONTROL 0 REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/S-0/0 R/S-0/0
SRLEN SRCLK2 SRCLK1 SRCLK0 SRQEN SRNQEN SRPS SRPR
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared S = Bit is set only
bit 7 SRLEN: SR Latch Enable bit
1 = SR Latch is enabled
0 = SR Latch is disabled
bit 6-4 SRCLK<2:0>: SR Latch Clock Divider bits
000 = Generates a 1 FOSC wide pulse every 4th FOSC cycle clock
001 = Generates a 1 FOSC wide pulse every 8th FOSC cycle clock
010 = Generates a 1 FOSC wide pulse every 16th FOSC cycle clock
011 = Generates a 1 FOSC wide pulse every 32nd FOSC cycle clock
100 = Generates a 1 FOSC wide pulse every 64th FOSC cycle clock
101 = Generates a 1 FOSC wide pulse every 128th FOSC cycle clock
110 = Generates a 1 FOSC wide pulse every 256th FOSC cycle clock
111 = Generates a 1 FOSC wide pulse every 512th FOSC cycle clock
bit 3 SRQEN: SR Latch Q Output Enable bit
If SRLEN = 1:
1 = Q is present on the SRQ pin
0 = External Q output is disabled
If SRLEN = 0:
SR Latch is disabled
bit 2 SRNQEN: SR Latch Q Output Enable bit
If SRLEN = 1:
1 =Q
is present on the SRnQ pin
0 = External Q output is disabled
If SRLEN = 0:
SR Latch is disabled
bit 1 SRPS: Pulse Set Input of the SR Latch bit(1)
1 = Pulse set input for 1 Q-clock period
0 = No effect on set input.
bit 0 SRPR: Pulse Reset Input of the SR Latch bit(1)
1 = Pulse reset input for 1 Q-clock period
0 = No effect on reset input.
Note 1: Set only, always reads back ‘0’.
PIC12F/LF1822/16F/LF1823
DS41413A-page 156 Preliminary 2010 Microchip Technology Inc.
REGISTER 17-2: SRCON1: SR LATCH CONTROL 1 REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
SRSPE SRSCKE SRSC2E(1) SRSC1E SRRPE SRRCKE SRRC2E(1) SRRC1E
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 SRSPE: SR Latch Peripheral Set Enable bit
1 = SR Latch is set when the SRI pin is high
0 = SRI pin has no effect on the set input of the SR Latch
bit 6 SRSCKE: SR Latch Set Clock Enable bit
1 = Set input of SR Latch is pulsed with SRCLK
0 = SRCLK has no effect on the set input of the SR Latch
bit 5 SRSC2E: SR Latch C2 Set Enable bit(1)
1 = SR Latch is set when the C2 Comparator output is high
0 = C2 Comparator output has no effect on the set input of the SR Latch
bit 4 SRSC1E: SR Latch C1 Set Enable bit
1 = SR Latch is set when the C1 Comparator output is high
0 = C1 Comparator output has no effect on the set input of the SR Latch
bit 3 SRRPE: SR Latch Peripheral Reset Enable bit
1 = SR Latch is reset when the SRI pin is high
0 = SRI pin has no effect on the reset input of the SR Latch
bit 2 SRRCKE: SR Latch Reset Clock Enable bit
1 = Reset input of SR Latch is pulsed with SRCLK
0 = SRCLK has no effect on the reset input of the SR Latch
bit 1 SRRC2E: SR Latch C2 Reset Enable bit(1)
1 = SR Latch is reset when the C2 Comparator output is high
0 = C2 Comparator output has no effect on the reset input of the SR Latch
bit 0 SRRC1E: SR Latch C1 Reset Enable bit
1 = SR Latch is reset when the C1 Comparator output is high
0 = C1 Comparator output has no effect on the reset input of the SR Latch
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 157
PIC12F/LF1822/16F/LF1823
TABLE 17-2: SUMMARY OF REGISTERS ASSOCIATED WITH SR LATCH MODULE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 122
SRCON0 SRLEN SRCLK2 SRCLK1 SRCLK0 SRQEN SRNQEN SRPS SRPR 155
SRCON1 SRSPE SRSCKE SRSC2E(1) SRSC1E SRRPE SRRCKE SRRC2E(1) SRRC1E 156
TRISA ——TRISA5TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the SR Latch module.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 158 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 159
PIC12F/LF1822/16F/LF1823
18.0 COMPARATOR MODULE
Comparators are used to interface analog circuits to a
digital circuit by comparing two analog voltages and
providing a digital indication of their relative magnitudes.
Comparators are very useful mixed signal building
blocks because they provide analog functionality
independent of program execution. The analog
comparator module includes the following features:
• Independent comparator control
• Programmable input selection
• Comparator output is available internally/externally
• Programmable output polarity
• Interrupt-on-change
• Wake-up from Sleep
• Programmable Speed/Power optimization
•PWM shutdown
• Programmable and fixed voltage reference
18.1 Comparator Overview
A single comparator is shown in Figure 18-1 along with
the relationship between the analog input levels and
the digital output. When the analog voltage at VIN+ is
less than the analog voltage at VIN-, the output of the
comparator is a digital low level. When the analog
voltage at VIN+ is greater than the analog voltage at
VIN-, the output of the comparator is a digital high level.
The PIC12F/LF1822 devices contain one comparator,
while the PIC16F/LF1823 devices contain two.
FIGURE 18-1: SINGLE COMPARATOR
–
+
VIN+
VIN-Output
Output
VIN+
VIN-
Note: The black areas of the output of the
comparator represents the uncertainty
due to input offsets and response time.
PIC12F/LF1822/16F/LF1823
DS41413A-page 160 Preliminary 2010 Microchip Technology Inc.
FIGURE 18-2: COMPARATOR 1 MODULE SIMPLIFIED BLOCK DIAGRAM (PIC12F/LF1822)
Note 1: When C1ON = 0, the Comparator will produce a ‘0’ at the output.
2: When C1ON = 0, all multiplexer inputs are disconnected.
3: Output of comparator can be frozen during debugging.
MUX
Cx(3)
0
1
C1ON(1)
CxNCH<1:0>
2
0
1
C1PCH<1:0>
C1IN1-
C1IN+
MUX
-
+
C1VN
C1VP
C1OUT
To ECCP PWM Logic
Q1
D
EN
Q
C1POL
MC1OUT
Set C1IF
0
1
C1SYNC C1OE
C1OUT
DQ
SYNCC1OUT
DAC
FVR Buffer2
C1IN0-
2
C1SP
C1HYS
det
Interrupt
det
Interrupt
C1INTN
C1INTP
To Data Bu s
2
3
TRIS bit
C1ON
(2)
(2)
(from Timer1)
T1CLK To Timer1 or SR Latch
VSS
2010 Microchip Technology Inc. Preliminary DS41413A-page 161
PIC12F/LF1822/16F/LF1823
FIGURE 18-3: COMPARATOR 1 AND 2 MODULES SIMPLIFIED BLOCK DIAGRAM
(PIC16F/LF1823)
Note 1: When CxON = 0, the Comparator will produce a ‘0’ at the output.
2: When CxON = 0, all multiplexer inputs are disconnected.
3: Output of comparator can be frozen during debugging.
MUX
Cx(3)
0
1
2
3
CxON(1)
CxNCH<1:0>
2
0
1
CXPCH<1:0>
C12IN1-
C12IN2-
C12IN3-
CXIN+
MUX
-
+
CxVN
CxVP
CXOUT
To ECCP PWM Logic
Q1
D
EN
Q
CXPOL
MCXOUT
Set CxIF
0
1
CXSYNC CXOE
CXOUT
DQ
SYNCCXOUT
DAC
FVR Buffer2
C12IN0-
2
CxSP
CxHYS
det
Interrupt
det
Interrupt
CxINTN
CxINTP
To Data Bu s
2
3
VSS TRIS bit
CxON
(2)
(2)
(from Timer1)
T1CLK To Timer1 or SR Latch
PIC12F/LF1822/16F/LF1823
DS41413A-page 162 Preliminary 2010 Microchip Technology Inc.
18.2 Comparator Control
Each comparator has 2 control registers: CMxCON0 and
CMxCON1.
The CMxCON0 registers (see Register 18-1) contain
Control and Status bits for the following:
• Enable
•Output selection
• Output polarity
• Speed/Power selection
• Hysteresis enable
• Output synchronization
The CMxCON1 registers (see Register 18-2) contain
Control bits for the following:
• Interrupt enable
• Interrupt edge polarity
• Positive input channel selection
• Negative input channel selection
18.2.1 COMPARATOR ENABLE
Setting the CxON bit of the CMxCON0 register enables
the comparator for operation. Clearing the CxON bit
disables the comparator resulting in minimum current
consumption.
18.2.2 COMPARATOR OUTPUT
SELECTION
The output of the comparator can be monitored by
reading either the CxOUT bit of the CMxCON0 register
or the MCxOUT bit of the CMOUT register. In order to
make the output available for an external connection,
the following conditions must be true:
• CxOE bit of the CMxCON0 register must be set
• Corresponding TRIS bit must be cleared
• CxON bit of the CMxCON0 register must be set
18.2.3 COMPARATOR OUTPUT POLARITY
Inverting the output of the comparator is functionally
equivalent to swapping the comparator inputs. The
polarity of the comparator output can be inverted by
setting the CxPOL bit of the CMxCON0 register.
Clearing the CxPOL bit results in a non-inverted output.
Table 18-1 shows the output state versus input
conditions, including polarity control.
18.2.4 COMPARATOR SPEED/POWER
SELECTION
The trade-off between speed or power can be opti-
mized during program execution with the CxSP control
bit. The default state for this bit is ‘1’ which selects the
normal speed mode. Device power consumption can
be optimized at the cost of slower comparator propaga-
tion delay by clearing the CxSP bit to ‘0’.
Note 1: The CxOE bit of the CMxCON0 register
overrides the PORT data latch. Setting
the CxON bit of the CMxCON0 register
has no impact on the port override.
2: The internal output of the comparator is
latched with each instruction cycle.
Unless otherwise specified, external
outputs are not latched.
TABLE 18-1: COMPARATOR OUTPUT
STATE VS. INPUT
CONDITIONS
Input Condition CxPOL CxOUT
CxVN > CxVP00
CxVN < CxVP01
CxVN > CxVP10
CxVN < CxVP11
2010 Microchip Technology Inc. Preliminary DS41413A-page 163
PIC12F/LF1822/16F/LF1823
18.3 Comparator Hysteresis
A selectable amount of separation voltage can be
added to the input pins of each comparator to provide a
hysteresis function to the overall operation. Hysteresis
is enabled by setting the CxHYS bit of the CMxCON0
register.
These hysteresis levels change as a function of the
comparator’s Speed/Power mode selection.
Table 18-2 shows the hysteresis levels.
These levels are approximate.
See Section 29.0 “Electrical Specifications” for
more information.
18.4 Timer1 Gate Operation
The output resulting from a comparator operation can
be used as a source for gate control of Timer1. See
Section 20.6 “Timer1 Gate” for more information.
This feature is useful for timing the duration or interval
of an analog event.
It is recommended that the comparator output be syn-
chronized to Timer1. This ensures that Timer1 does not
increment while a change in the comparator is occur-
ring.
18.4.1 COMPARATOR OUTPUT
SYNCHRONIZATION
The output from either comparator, C1 or C2, can be
synchronized with Timer1 by setting the CxSYNC bit of
the CMxCON0 register.
Once enabled, the comparator output is latched on the
falling edge of the Timer1 source clock. If a prescaler is
used with Timer1, the comparator output is latched after
the prescaling function. To prevent a race condition, the
comparator output is latched on the falling edge of the
Timer1 clock source and Timer1 increments on the
rising edge of its clock source. See the Comparator
Block Diagram (Figure ) and the Timer1 Block Diagram
(Figure 20-1) for more information.
18.5 Comparator Interrupt
An interrupt can be generated upon a change in the
output value of the comparator for each comparator, a
rising edge detector and a falling edge detector are
present.
When either edge detector is triggered and its associ-
ated enable bit is set (CxINTP and/or CxINTN bits of
the CMxCON1 register), the Corresponding Interrupt
Flag bit (CxIF bit of the PIR2 register) will be set.
To enable the interrupt, you must set the following bits:
• CxON, CxPOL and CxSP bits of the CMxCON0
register
• CxIE bit of the PIE2 register
• CxINTP bit of the CMxCON1 register (for a rising
edge detection)
• CxINTN bit of the CMxCON1 register (for a falling
edge detection)
• PEIE and GIE bits of the INTCON register
The associated interrupt flag bit, CxIF bit of the PIR2
register, must be cleared in software. If another edge is
detected while this flag is being cleared, the flag will still
be set at the end of the sequence.
18.6 Comparator Positive Input
Selection
Configuring the CxPCH<1:0> bits of the CMxCON1
register directs an internal voltage reference or an
analog pin to the non-inverting input of the comparator:
• C1IN+ or C2IN+ analog pin
•DAC
• FVR (Fixed Voltage Reference)
•V
SS (Ground)
See Section 14.0 “Fixed Voltage Reference (FVR)”
for more information on the Fixed Voltage Reference
module.
See Section 16.0 “Digital-to-Analog Converter
(DAC) Module” for more information on the DAC input
signal.
Any time the comparator is disabled (CxON = 0), all
comparator inputs are disabled.
TABLE 18-2: HYSTERESIS LEVELS
CxSP CxHYS Enabled CxHYS Disabled
0 ± 3mV << ± 1mV
1± 20mV ± 3mV
Note: Although a comparator is disabled, an
interrupt can be generated by changing
the output polarity with the CxPOL bit of
the CMxCON0 register, or by switching the
comparator on or off with the CxON bit of
the CMxCON0 register.
PIC12F/LF1822/16F/LF1823
DS41413A-page 164 Preliminary 2010 Microchip Technology Inc.
18.7 Comparator Negative Input
Selection
The CxNCH<1:0> bits of the CMxCON0 register direct
one of the analog pins to the comparator inverting
input.
18.8 Comparator Response Time
The comparator output is indeterminate for a period of
time after the change of an input source or the selection
of a new reference voltage. This period is referred to as
the response time. The response time of the comparator
differs from the settling time of the voltage reference.
Therefore, both of these times must be considered when
determining the total response time to a comparator
input change. See the Comparator and Voltage Refer-
ence Specifications in Section 29.0 “Electrical Specifi-
cations” for more details.
18.9 Interaction with ECCP Logic
The C1 and C2 comparators can be used as general
purpose comparators. Their outputs can be brought
out to the C1OUT and C2OUT pins. When the ECCP
Auto-Shutdown is active it can use one or both
comparators. If auto-restart is also enabled, the
comparators can be configured as a closed loop
analog feedback to the ECCP, thereby, creating an
analog controlled PWM.
18.10 Analog Input Connection
Considerations
A simplified circuit for an analog input is shown in
Figure 18-4. Since the analog input pins share their
connection with a digital input, they have reverse
biased ESD protection diodes to VDD and VSS. The
analog input, therefore, must be between VSS and VDD.
If the input voltage deviates from this range by more
than 0.6V in either direction, one of the diodes is for-
ward biased and a latch-up may occur.
A maximum source impedance of 10 k is recommended
for the analog sources. Also, any external component
connected to an analog input pin, such as a capacitor or
a Zener diode, should have very little leakage current to
minimize inaccuracies introduced.
FIGURE 18-4: ANALOG INPUT MODEL
Note: To use CxIN+ and CxINx- pins as analog
input, the appropriate bits must be set in
the ANSEL register and the corresponding
TRIS bits must also be set to disable the
output drivers.
Note 1: When reading a PORT register, all pins
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert as an analog input, according to
the input specification.
2: Analog levels on any pin defined as a
digital input, may cause the input buffer to
consume more current than is specified.
VA
Rs < 10K
CPIN
5 pF
VDD
VT 0.6V
VT 0.6V
RIC
ILEAKAGE(1)
Vss
Legend: CPIN = Input Capacitance
ILEAKAGE = Leakage Current at the pin due to various junctions
RIC = Interconnect Resistance
RS= Source Impedance
VA= Analog Voltage
VT= Threshold Voltage
To Comparator
Note 1: See Section 29.0 “Electrical Specifications”.
Analog
Input
pin
2010 Microchip Technology Inc. Preliminary DS41413A-page 165
PIC12F/LF1822/16F/LF1823
REGISTER 18-1: CMxCON0: COMPARATOR X CONTROL REGISTER 0
R/W-0/0 R-0/0 R/W-0/0 R/W-0/0 U-0 R/W-1/1 R/W-0/0 R/W-0/0
CxON CxOUT CxOE CxPOL —CxSP CxHYS CxSYNC
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 CxON: Comparator Enable bit
1 = Comparator is enabled and consumes no active power
0 = Comparator is disabled
bit 6 CxOUT: Comparator Output bit
If CxPOL = 1 (inverted polarity):
1 = CxVP < CxVN
0 = CxVP > CxVN
If CxPOL = 0 (non-inverted polarity):
1 = CxVP > CxVN
0 = CxVP < CxVN
bit 5 CxOE: Comparator Output Enable bit
1 = CxOUT is present on the CxOUT pin. Requires that the associated TRIS bit be cleared to actually
drive the pin. Not affected by CxON.
0 = CxOUT is internal only
bit 4 CxPOL: Comparator Output Polarity Select bit
1 = Comparator output is inverted
0 = Comparator output is not inverted
bit 3 Unimplemented: Read as ‘0’
bit 2 CxSP: Comparator Speed/Power Select bit
1 = Comparator operates in normal power, higher speed mode
0 = Comparator operates in low-power, low-speed mode
bit 1 CxHYS: Comparator Hysteresis Enable bit
1 = Comparator hysteresis enabled
0 = Comparator hysteresis disabled
bit 0 CxSYNC: Comparator Output Synchronous Mode bit
1 = Comparator output to Timer1 and I/O pin is synchronous to changes on Timer1 clock source.
Output updated on the falling edge of Timer1 clock source.
0 = Comparator output to Timer1 and I/O pin is asynchronous.
PIC12F/LF1822/16F/LF1823
DS41413A-page 166 Preliminary 2010 Microchip Technology Inc.
REGISTER 18-2: CMxCON1: COMPARATOR CX CONTROL REGISTER 1
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 U-0 R/W-0/0 R/W-0/0
CxINTP CxINTN CxPCH<1:0> — — CxNCH1(1) CxNCH0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 CxINTP: Comparator Interrupt on Positive Going Edge Enable bits
1 = The CxIF interrupt flag will be set upon a positive going edge of the CxOUT bit
0 = No interrupt flag will be set on a positive going edge of the CxOUT bit
bit 6 CxINTN: Comparator Interrupt on Negative Going Edge Enable bits
1 = The CxIF interrupt flag will be set upon a negative going edge of the CxOUT bit
0 = No interrupt flag will be set on a negative going edge of the CxOUT bit
bit 5-4 CxPCH<1:0>: Comparator Positive Input Channel Select bits
00 = CxVP connects to CxIN+ pin
01 = CxVP connects to DAC Voltage Reference
10 = CxVP connects to FVR Voltage Reference
bit 3-2 Unimplemented: Read as ‘0’
bit 1-0 CxNCH<1:0>: Comparator Negative Input Channel Select bits
PIC12F/LF1822:
0 = C1VN connects to C1IN0- pin
1 = C1VN connects to C1IN1- pin
PIC16F/LF1823:
00 = CxVN connects to C12IN0- pin
01 = CxVN connects to C12IN1- pin
10 = CxVN connects to C12IN2- pin
11 = CxVN connects to C12IN3- pin
Note 1: PIC16F/LF1823 only.
REGISTER 18-3: CMOUT: COMPARATOR OUTPUT REGISTER
U-0 U-0 U-0 U-0 U-0 U-0 R-0/0 R-0/0
— — — — — — MC2OUT(1) MC1OUT
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-2 Unimplemented: Read as ‘0’
bit 1 MC2OUT: Mirror Copy of C2OUT bit(1)
bit 0 MC1OUT: Mirror Copy of C1OUT bit
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 167
PIC12F/LF1822/16F/LF1823
TABLE 18-3: SUMMARY OF REGISTERS ASSOCIATED WITH COMPARATOR MODULE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 122
CM1CON0 C1ON C1OUT C1OE C1POL — C1SP C1HYS C1SYNC 165
CM1CON1 C1INTP C1INTN C1PCH1 C1PCH0 — — — C1NCH0 166
CM2CON0(1) C2ON C2OUT C2OE C2POL — C2SP C2HYS C2SYNC 165
CM2CON1(1) C2INTP C2INTN C2PCH1 C2PCH0 —— C2NCH1 C2NCH0 166
CMOUT — — — — — —MC2OUT
(1) MC1OUT 166
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE ———91
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF ———93
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) —— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the comparator module.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 168 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 169
PIC12F/LF1822/16F/LF1823
19.0 TIMER0 MODULE
The Timer0 module is an 8-bit timer/counter with the
following features:
• 8-bit timer/counter register (TMR0)
• 8-bit prescaler (independent of Watchdog Timer)
• Programmable internal or external clock source
• Programmable external clock edge selection
• Interrupt on overflow
• TMR0 can be used to gate Timer1
Figure 19-1 is a block diagram of the Timer0 module.
19.1 Timer0 Operation
The Timer0 module can be used as either an 8-bit timer
or an 8-bit counter.
19.1.1 8-BIT TIMER MODE
The Timer0 module will increment every instruction
cycle, if used without a prescaler. 8-Bit Timer mode is
selected by clearing the TMR0CS bit of the OPTION
register.
When TMR0 is written, the increment is inhibited for
two instruction cycles immediately following the write.
19.1.2 8-BIT COUNTER MODE
In 8-bit Counter mode, the Timer0 module will increment
on every rising or falling edge of the T0CKI pin or the
Capacitive Sensing Oscillator (CPSCLK) signal.
8-Bit Counter mode using the T0CKI pin is selected by
setting the TMR0CS bit in the OPTION register to ‘1’
and resetting the T0XCS bit in the CPSCON0 register to
‘0’.
8-Bit Counter mode using the Capacitive Sensing
Oscillator (CPSCLK) signal is selected by setting the
TMR0CS bit in the OPTION register to ‘1’ and setting
the T0XCS bit in the CPSCON0 register to ‘1’.
The rising or falling transition of the incrementing edge
for either input source is determined by the TMR0SE bit
in the OPTION register.
FIGURE 19-1: BLOCK DIAGRAM OF THE TIMER0
Note: The value written to the TMR0 register can
be adjusted, in order to account for the two
instruction cycle delay when TMR0 is
written.
T0CKI
TMR0SE
TMR0
PS<2:0>
Data Bus
Set Flag bit TMR0IF
on Overflow
TMR0CS
0
1
0
1
8
8
8-bit
Prescaler
FOSC/4
PSA
Sync
2 TCY
Overflow to Timer1
1
0
From CPSCLK
T0XCS
PIC12F/LF1822/16F/LF1823
DS41413A-page 170 Preliminary 2010 Microchip Technology Inc.
19.1.3 SOFTWARE PROGRAMMABLE
PRESCALER
A software programmable prescaler is available for
exclusive use with Timer0. The prescaler is enabled by
clearing the PSA bit of the OPTION register.
There are 8 prescaler options for the Timer0 module
ranging from 1:2 to 1:256. The prescale values are
selectable via the PS<2:0> bits of the OPTION register.
In order to have a 1:1 prescaler value for the Timer0
module, the prescaler must be disabled by setting the
PSA bit of the OPTION register.
The prescaler is not readable or writable. All instructions
writing to the TMR0 register will clear the prescaler.
19.1.4 TIMER0 INTERRUPT
Timer0 will generate an interrupt when the TMR0
register overflows from FFh to 00h. The TMR0IF
interrupt flag bit of the INTCON register is set every
time the TMR0 register overflows, regardless of
whether or not the Timer0 interrupt is enabled. The
TMR0IF bit can only be cleared in software. The Timer0
interrupt enable is the TMR0IE bit of the INTCON
register.
19.1.5 8-BIT COUNTER MODE
SYNCHRONIZATION
When in 8-Bit Counter mode, the incrementing edge on
the T0CKI pin must be synchronized to the instruction
clock. Synchronization can be accomplished by
sampling the prescaler output on the Q2 and Q4 cycles
of the instruction clock. The high and low periods of the
external clocking source must meet the timing
requirements as shown in Section 29.0 “Electrical
Specifications”.
19.1.6 OPERATION DURING SLEEP
Timer0 cannot operate while the processor is in Sleep
mode. The contents of the TMR0 register will remain
unchanged while the processor is in Sleep mode.
Note: The Watchdog Timer (WDT) uses its own
independent prescaler.
Note: The Timer0 interrupt cannot wake the
processor from Sleep since the timer is
frozen during Sleep.
2010 Microchip Technology Inc. Preliminary DS41413A-page 171
PIC12F/LF1822/16F/LF1823
TABLE 19-1: SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0
REGISTER 19-1: OPTION_REG: OPTION REGISTER
R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1
WPUEN INTEDG TMR0CS TMR0SE PSA PS<2:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 WPUEN: Weak Pull-up Enable bit
1 = All weak pull-ups are disabled (except MCLR, if it is enabled)
0 = Weak pull-ups are enabled by individual WPUx latch values
bit 6 INTEDG: Interrupt Edge Select bit
1 = Interrupt on rising edge of RA2/INT pin
0 = Interrupt on falling edge of RA2/INT pin
bit 5 TMR0CS: Timer0 Clock Source Select bit
1 = Transition on RA2/T0CKI pin
0 = Internal instruction cycle clock (FOSC/4)
bit 4 TMR0SE: Timer0 Source Edge Select bit
1 = Increment on high-to-low transition on RA2/T0CKI pin
0 = Increment on low-to-high transition on RA2/T0CKI pin
bit 3 PSA: Prescaler Assignment bit
1 = Prescaler is not assigned to the Timer0 module
0 = Prescaler is assigned to the Timer0 module
bit 2-0 PS<2:0>: Prescaler Rate Select bits
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CPSCON0 CPSON CPSRM — — CPSRNG1 CPSRNG0 CPSOUT T0XCS 313
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
OPTION_REG WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 171
TMR0 Timer0 Module Register 169*
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by the Timer0 module.
* Page provides register information.
000
001
010
011
100
101
110
111
1 : 2
1 : 4
1 : 8
1 : 16
1 : 32
1 : 64
1 : 128
1 : 256
Bit Value Timer0 Rate
PIC12F/LF1822/16F/LF1823
DS41413A-page 172 Preliminary 2010 Microchip Technology Inc.
20.0 TIMER1 MODULE WITH GATE
CONTROL
The Timer1 module is a 16-bit timer/counter with the
following features:
• 16-bit timer/counter register pair (TMR1H:TMR1L)
• Programmable internal or external clock source
• 2-bit prescaler
• Dedicated 32 kHz oscillator circuit
• Optionally synchronized comparator out
• Multiple Timer1 gate (count enable) sources
• Interrupt on overflow
• Wake-up on overflow (external clock,
Asynchronous mode only)
• Time base for the Capture/Compare function
• Special Event Trigger (with CCP/ECCP)
• Selectable Gate Source Polarity
• Gate Toggle Mode
• Gate Single-pulse Mode
• Gate Value Status
• Gate Event Interrupt
Figure 20-1 is a block diagram of the Timer1 module.
FIGURE 20-1: TIMER1 BLOCK DIAGRAM
TMR1H TMR1L
T1SYNC
T1CKPS<1:0>
Prescaler
1, 2, 4, 8
0
1
Synchronized
clock input
2
Set flag bit
TMR1IF on
Overflow TMR1(2)
TMR1ON
Note 1: ST Buffer is high speed type when using T1CKI.
2: Timer1 register increments on rising edge.
3: Synchronize does not operate while in Sleep.
T1G
T1OSC
FOSC/4
Internal
Clock
T1OSO
T1OSI
T1OSCEN
1
0
T1CKI
TMR1CS<1:0>
(1)
Synchronize(3)
det
Sleep input
TMR1GE
0
1
00
01
10
11
T1GPOL
D
Q
CK
Q
0
1
T1GVAL
T1GTM
Single Pulse
Acq. Control
T1GSPM
T1GGO/DONE
T1GSS<1:0>
EN
OUT
10
11
00
01
FOSC
Internal
Clock
Cap. Sensing
R
D
EN
Q
Q1
RD
T1GCON
Data Bus
det
Interrupt
TMR1GIF
Set
T1CLK
FOSC/2
Internal
Clock
D
EN
Q
T1G_IN
TMR1ON
Oscillator
From Timer0
Comparator 1
Overflow
Comparator 2
SYNCC2OUT
SYNCC1OUT
To Comparator Module
To Clock Switching Modules
2010 Microchip Technology Inc. Preliminary DS41413A-page 173
PIC12F/LF1822/16F/LF1823
20.1 Timer1 Operation
The Timer1 module is a 16-bit incrementing counter
which is accessed through the TMR1H:TMR1L register
pair. Writes to TMR1H or TMR1L directly update the
counter.
When used with an internal clock source, the module is
a timer and increments on every instruction cycle.
When used with an external clock source, the module
can be used as either a timer or counter and incre-
ments on every selected edge of the external source.
Timer1 is enabled by configuring the TMR1ON and
TMR1GE bits in the T1CON and T1GCON registers,
respectively. Table 20-1 displays the Timer1 enable
selections.
20.2 Clock Source Selection
The TMR1CS<1:0> and T1OSCEN bits of the T1CON
register are used to select the clock source for Timer1.
Table 20-2 displays the clock source selections.
20.2.1 INTERNAL CLOCK SOURCE
When the internal clock source is selected the
TMR1H:TMR1L register pair will increment on multiples
of FOSC as determined by the Timer1 prescaler.
When the FOSC internal clock source is selected, the
Timer1 register value will increment by four counts every
instruction clock cycle. Due to this condition, a 2 LSB
error in resolution will occur when reading the Timer1
value. To utilize the full resolution of Timer1, an
asynchronous input signal must be used to gate the
Timer1 clock input.
The following asynchronous sources may be used:
• Asynchronous event on the T1G pin to Timer1
Gate
• C1 or C2 comparator input to Timer1 Gate
20.2.2 EXTERNAL CLOCK SOURCE
When the external clock source is selected, the Timer1
module may work as a timer or a counter.
When enabled to count, Timer1 is incremented on the
rising edge of the external clock input T1CKI or the
capacitive sensing oscillator signal. Either of these
external clock sources can be synchronized to the
microcontroller system clock or they can run
asynchronously.
When used as a timer with a clock oscillator, an
external 32.768 kHz crystal can be used in conjunction
with the dedicated internal oscillator circuit.
TABLE 20-1: TIMER1 ENABLE
SELECTIONS
TMR1ON TMR1GE Timer1
Operation
00Off
01Off
10Always On
11Count Enabled
Note: In Counter mode, a falling edge must be
registered by the counter prior to the first
incrementing rising edge after any one or
more of the following conditions:
• Timer1 enabled after POR
• Write to TMR1H or TMR1L
• Timer1 is disabled
• Timer1 is disabled (TMR1ON = 0)
when T1CKI is high then Timer1 is
enabled (TMR1ON=1) when T1CKI is
low.
TABLE 20-2: CLOCK SOURCE SELECTIONS
TMR1CS1 TMR1CS0 T1OSCEN Clock Source
01xSystem Clock (FOSC)
00xInstruction Clock (FOSC/4)
11xCapacitive Sensing Oscillator
100External Clocking on T1CKI Pin
101Osc.Circuit On T1OSI/T1OSO Pins
PIC12F/LF1822/16F/LF1823
DS41413A-page 174 Preliminary 2010 Microchip Technology Inc.
20.3 Timer1 Prescaler
Timer1 has four prescaler options allowing 1, 2, 4 or 8
divisions of the clock input. The T1CKPS bits of the
T1CON register control the prescale counter. The
prescale counter is not directly readable or writable;
however, the prescaler counter is cleared upon a write to
TMR1H or TMR1L.
20.4 Timer1 Oscillator
A dedicated low-power 32.768 kHz oscillator circuit is
built-in between pins T1OSI (input) and T1OSO
(amplifier output). This internal circuit is to be used in
conjunction with an external 32.768 kHz crystal.
The oscillator circuit is enabled by setting the
T1OSCEN bit of the T1CON register. The oscillator will
continue to run during Sleep.
20.5 Timer1 Operation in
Asynchronous Counter Mode
If control bit T1SYNC of the T1CON register is set, the
external clock input is not synchronized. The timer
increments asynchronously to the internal phase
clocks. If external clock source is selected then the
timer will continue to run during Sleep and can
generate an interrupt on overflow, which will wake-up
the processor. However, special precautions in
software are needed to read/write the timer (see
Section 20.5.1 “Reading and Writing Timer1 in
Asynchronous Counter Mode”).
20.5.1 READING AND WRITING TIMER1 IN
ASYNCHRONOUS COUNTER
MODE
Reading TMR1H or TMR1L while the timer is running
from an external asynchronous clock will ensure a valid
read (taken care of in hardware). However, the user
should keep in mind that reading the 16-bit timer in two
8-bit values itself, poses certain problems, since the
timer may overflow between the reads.
For writes, it is recommended that the user simply stop
the timer and write the desired values. A write
contention may occur by writing to the timer registers,
while the register is incrementing. This may produce an
unpredictable value in the TMR1H:TMR1L register pair.
20.6 Timer1 Gate
Timer1 can be configured to count freely or the count
can be enabled and disabled using Timer1 Gate
circuitry. This is also referred to as Timer1 Gate Enable.
Timer1 Gate can also be driven by multiple selectable
sources.
20.6.1 TIMER1 GATE ENABLE
The Timer1 Gate Enable mode is enabled by setting
the TMR1GE bit of the T1GCON register. The polarity
of the Timer1 Gate Enable mode is configured using
the T1GPOL bit of the T1GCON register.
When Timer1 Gate Enable mode is enabled, Timer1
will increment on the rising edge of the Timer1 clock
source. When Timer1 Gate Enable mode is disabled,
no incrementing will occur and Timer1 will hold the
current count. See Figure 20-3 for timing details.
20.6.2 TIMER1 GATE SOURCE
SELECTION
The Timer1 Gate source can be selected from one of
four different sources. Source selection is controlled by
the T1GSS bits of the T1GCON register. The polarity
for each available source is also selectable. Polarity
selection is controlled by the T1GPOL bit of the
T1GCON register.
TABLE 20-4: TIMER1 GATE SOURCES
Note: The oscillator requires a start-up and
stabilization time before use. Thus,
T1OSCEN should be set and a suitable
delay observed prior to enabling Timer1.
Note: When switching from synchronous to
asynchronous operation, it is possible to
skip an increment. When switching from
asynchronous to synchronous operation,
it is possible to produce an additional
increment.
TABLE 20-3: TIMER1 GATE ENABLE
SELECTIONS
T1CLK T1GPOL T1G Timer1 Operation
00Counts
01Holds Count
10Holds Count
11Counts
T1GSS Timer1 Gate Source
00 Timer1 Gate Pin
01 Overflow of Timer0
(TMR0 increments from FFh to 00h)
10 Comparator 1 Output SYNCC1OUT
(optionally Timer1 synchronized output)
11 Comparator 2 Output SYNCC2OUT
(optionally Timer1 synchronized output)
2010 Microchip Technology Inc. Preliminary DS41413A-page 175
PIC12F/LF1822/16F/LF1823
20.6.2.1 T1G Pin Gate Operation
The T1G pin is one source for Timer1 Gate Control. It
can be used to supply an external source to the Timer1
Gate circuitry.
20.6.2.2 Timer0 Overflow Gate Operation
When Timer0 increments from FFh to 00h, a
low-to-high pulse will automatically be generated and
internally supplied to the Timer1 Gate circuitry.
20.6.2.3 Comparator C1 Gate Operation
The output resulting from a Comparator 1 operation can
be selected as a source for Timer1 Gate Control. The
Comparator 1 output (SYNCC1OUT) can be
synchronized to the Timer1 clock or left asynchronous.
For more information see Section 18.4.1 “Comparator
Output Synchronization”.
20.6.2.4 Comparator C2 Gate Operation
(PIC16F/LF1823)
The output resulting from a Comparator 2 operation
can be selected as a source for Timer1 Gate Control.
The Comparator 2 output (SYNCC2OUT) can be
synchronized to the Timer1 clock or left asynchronous.
For more information see Section 18.4.1 “Comparator
Output Synchronization”.
20.6.3 TIMER1 GATE TOGGLE MODE
When Timer1 Gate Toggle mode is enabled, it is possi-
ble to measure the full-cycle length of a Timer1 gate
signal, as opposed to the duration of a single level
pulse.
The Timer1 Gate source is routed through a flip-flop
that changes state on every incrementing edge of the
signal. See Figure 20-4 for timing details.
Timer1 Gate Toggle mode is enabled by setting the
T1GTM bit of the T1GCON register. When the T1GTM
bit is cleared, the flip-flop is cleared and held clear. This
is necessary in order to control which edge is
measured.
20.6.4 TIMER1 GATE SINGLE-PULSE
MODE
When Timer1 Gate Single-Pulse mode is enabled, it is
possible to capture a single pulse gate event. Timer1
Gate Single-Pulse mode is first enabled by setting the
T1GSPM bit in the T1GCON register. Next, the
T1GGO/DONE bit in the T1GCON register must be set.
The Timer1 will be fully enabled on the next
incrementing edge. On the next trailing edge of the
pulse, the T1GGO/DONE bit will automatically be
cleared. No other gate events will be allowed to
increment Timer1 until the T1GGO/DONE bit is once
again set in software.
Clearing the T1GSPM bit of the T1GCON register will
also clear the T1GGO/DONE bit. See Figure 20-5 for
timing details.
Enabling the Toggle mode and the Single-Pulse mode
simultaneously will permit both sections to work
together. This allows the cycle times on the Timer1
Gate source to be measured. See Figure 20-6 for
timing details.
20.6.5 TIMER1 GATE VALUE STATUS
When Timer1 Gate Value Status is utilized, it is possible
to read the most current level of the gate control value.
The value is stored in the T1GVAL bit in the T1GCON
register. The T1GVAL bit is valid even when the Timer1
Gate is not enabled (TMR1GE bit is cleared).
20.6.6 TIMER1 GATE EVENT INTERRUPT
When Timer1 Gate Event Interrupt is enabled, it is pos-
sible to generate an interrupt upon the completion of a
gate event. When the falling edge of T1GVAL occurs,
the TMR1GIF flag bit in the PIR1 register will be set. If
the TMR1GIE bit in the PIE1 register is set, then an
interrupt will be recognized.
The TMR1GIF flag bit operates even when the Timer1
Gate is not enabled (TMR1GE bit is cleared).
Note: Enabling Toggle mode at the same time as
changing the gate polarity may result in
indeterminate operation.
PIC12F/LF1822/16F/LF1823
DS41413A-page 176 Preliminary 2010 Microchip Technology Inc.
20.7 Timer1 Interrupt
The Timer1 register pair (TMR1H:TMR1L) increments
to FFFFh and rolls over to 0000h. When Timer1 rolls
over, the Timer1 interrupt flag bit of the PIR1 register is
set. To enable the interrupt on rollover, you must set
these bits:
• TMR1ON bit of the T1CON register
• TMR1IE bit of the PIE1 register
• PEIE bit of the INTCON register
• GIE bit of the INTCON register
The interrupt is cleared by clearing the TMR1IF bit in
the Interrupt Service Routine.
20.8 Timer1 Operation During Sleep
Timer1 can only operate during Sleep when setup in
Asynchronous Counter mode. In this mode, an external
crystal or clock source can be used to increment the
counter. To set up the timer to wake the device:
• TMR1ON bit of the T1CON register must be set
• TMR1IE bit of the PIE1 register must be set
• PEIE bit of the INTCON register must be set
• T1SYNC bit of the T1CON register must be set
• TMR1CS bits of the T1CON register must be
configured
• T1OSCEN bit of the T1CON register must be
configured
The device will wake-up on an overflow and execute
the next instructions. If the GIE bit of the INTCON
register is set, the device will call the Interrupt Service
Routine.
Timer1 oscillator will continue to operate in Sleep
regardless of the T1SYNC bit setting.
20.9 ECCP/CCP Capture/Compare Time
Base
The CCP1 module uses the TMR1H:TMR1L register
pair as the time base when operating in Capture or
Compare mode.
In Capture mode, the value in the TMR1H:TMR1L
register pair is copied into the CCPR1H:CCPR1L
register pair on a configured event.
In Compare mode, an event is triggered when the value
CCPR1H:CCPR1L register pair matches the value in
the TMR1H:TMR1L register pair. This event can be a
Special Event Trigger.
For more information, see Section 23.0
“Capture/Compare/PWM Modules”.
20.10 ECCP/CCP Special Event Trigger
When any of the CCP’s are configured to trigger a spe-
cial event, the trigger will clear the TMR1H:TMR1L reg-
ister pair. This special event does not cause a Timer1
interrupt. The CCP1 module may still be configured to
generate a CCP interrupt.
In this mode of operation, the CCPR1H:CCPR1L
register pair becomes the period register for Timer1.
Timer1 should be synchronized and FOSC/4 should be
selected as the clock source in order to utilize the Spe-
cial Event Trigger. Asynchronous operation of Timer1
can cause a Special Event Trigger to be missed.
In the event that a write to TMR1H or TMR1L coincides
with a Special Event Trigger from the CCP, the write will
take precedence.
For more information, see Section 15.2.5 “Special
Event Trigger”.
FIGURE 20-2: TIMER1 INCREMENTING EDGE
Note: The TMR1H:TMR1L register pair and the
TMR1IF bit should be cleared before
enabling interrupts.
T1CKI = 1
when TMR1
Enabled
T1CKI = 0
when TMR1
Enabled
Note 1: Arrows indicate counter increments.
2: In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock.
2010 Microchip Technology Inc. Preliminary DS41413A-page 177
PIC12F/LF1822/16F/LF1823
FIGURE 20-3: TIMER1 GATE ENABLE MODE
FIGURE 20-4: TIMER1 GATE TOGGLE MODE
TMR1GE
T1GPOL
T1G_IN
T1CKI
T1GVAL
Timer1 N N + 1 N + 2 N + 3 N + 4
TMR1GE
T1GPOL
T1GTM
T1G_IN
T1CKI
T1GVAL
Timer1 N N + 1 N + 2 N + 3 N + 4 N + 5 N + 6 N + 7 N + 8
PIC12F/LF1822/16F/LF1823
DS41413A-page 178 Preliminary 2010 Microchip Technology Inc.
FIGURE 20-5: TIMER1 GATE SINGLE-PULSE MODE
TMR1GE
T1GPOL
T1G_IN
T1CKI
T1GVAL
Timer1 N N + 1 N + 2
T1GSPM
T1GGO/
DONE
Set by software
Cleared by hardware on
falling edge of T1GVAL
Set by hardware on
falling edge of T1GVAL
Cleared by software
Cleared by
software
TMR1GIF
Counting enabled on
rising edge of T1G
2010 Microchip Technology Inc. Preliminary DS41413A-page 179
PIC12F/LF1822/16F/LF1823
FIGURE 20-6: TIMER1 GATE SINGLE-PULSE AND TOGGLE COMBINED MODE
TMR1GE
T1GPOL
T1G_IN
T1CKI
T1GVAL
Timer1 NN + 1
N + 2
T1GSPM
T1GGO/
DONE
Set by software
Cleared by hardware on
falling edge of T1GVAL
Set by hardware on
falling edge of T1GVAL
Cleared by software
Cleared by
software
TMR1GIF
T1GTM
Counting enabled on
rising edge of T1G
N + 4
N + 3
PIC12F/LF1822/16F/LF1823
DS41413A-page 180 Preliminary 2010 Microchip Technology Inc.
20.11 Timer1 Control Register
The Timer1 Control register (T1CON), shown in
Register 20-1, is used to control Timer1 and select the
various features of the Timer1 module.
REGISTER 20-1: T1CON: TIMER1 CONTROL REGISTER
R/W-0/u R/W-0/u R/W-0/u R/W-0/u R/W-0/u R/W-0/u U-0 R/W-0/u
TMR1CS<1:0> T1CKPS<1:0> T1OSCEN T1SYNC —TMR1ON
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 TMR1CS<1:0>: Timer1 Clock Source Select bits
11 = Timer1 clock source is Capacitive Sensing Oscillator (CAPOSC)
10 = Timer1 clock source is pin or oscillator:
If T1OSCEN = 0:
External clock from T1CKI pin (on the rising edge)
If T1OSCEN = 1:
Crystal oscillator on T1OSI/T1OSO pins
01 = Timer1 clock source is system clock (FOSC)
00 = Timer1 clock source is instruction clock (FOSC/4)
bit 5-4 T1CKPS<1:0>: Timer1 Input Clock Prescale Select bits
11 = 1:8 Prescale value
10 = 1:4 Prescale value
01 = 1:2 Prescale value
00 = 1:1 Prescale value
bit 3 T1OSCEN: LP Oscillator Enable Control bit
1 = Dedicated Timer1 oscillator circuit enabled
0 = Dedicated Timer1 oscillator circuit disabled
bit 2 T1SYNC: Timer1 External Clock Input Synchronization Control bit
TMR1CS<1:0> = 1X
1 = Do not synchronize external clock input
0 = Synchronize external clock input with system clock (FOSC)
TMR1CS<1:0> = 0X
This bit is ignored. Timer1 uses the internal clock when TMR1CS<1:0> = 1X.
bit 1 Unimplemented: Read as ‘0’
bit 0 TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Clears Timer1 Gate flip-flop
2010 Microchip Technology Inc. Preliminary DS41413A-page 181
PIC12F/LF1822/16F/LF1823
20.12 Timer1 Gate Control Register
The Timer1 Gate Control register (T1GCON), shown in
Register 20-2, is used to control Timer1 Gate.
REGISTER 20-2: T1GCON: TIMER1 GATE CONTROL REGISTER
R/W-0/u R/W-0/u R/W-0/u R/W-0/u R/W/HC-0/u R-x/x R/W-0/u R/W-0/u
TMR1GE T1GPOL T1GTM T1GSPM T1GGO/
DONE
T1GVAL T1GSS<1:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared HC = Bit is cleared by hardware
bit 7 TMR1GE: Timer1 Gate Enable bit
If TMR1ON = 0:
This bit is ignored
If TMR1ON = 1:
1 = Timer1 counting is controlled by the Timer1 gate function
0 = Timer1 counts regardless of Timer1 gate function
bit 6 T1GPOL: Timer1 Gate Polarity bit
1 = Timer1 gate is active-high (Timer1 counts when gate is high)
0 = Timer1 gate is active-low (Timer1 counts when gate is low)
bit 5 T1GTM: Timer1 Gate Toggle Mode bit
1 = Timer1 Gate Toggle mode is enabled
0 = Timer1 Gate Toggle mode is disabled and toggle flip-flop is cleared
Timer1 gate flip-flop toggles on every rising edge.
bit 4 T1GSPM: Timer1 Gate Single-Pulse Mode bit
1 = Timer1 gate Single-Pulse mode is enabled and is controlling Timer1 gate
0 = Timer1 gate Single-Pulse mode is disabled
bit 3 T1GGO/DONE: Timer1 Gate Single-Pulse Acquisition Status bit
1 = Timer1 gate single-pulse acquisition is ready, waiting for an edge
0 = Timer1 gate single-pulse acquisition has completed or has not been started
This bit is automatically cleared when T1GSPM is cleared.
bit 2 T1GVAL: Timer1 Gate Current State bit
Indicates the current state of the Timer1 gate that could be provided to TMR1H:TMR1L.
Unaffected by Timer1 Gate Enable (TMR1GE).
bit 1-0 T1GSS<1:0>: Timer1 Gate Source Select bits
00 = Timer1 Gate pin
01 = Timer0 overflow output
10 = Comparator 1 optionally synchronized output (SYNCC1OUT)
11 = Comparator 2 optionally synchronized output (SYNCC2OUT)(1)
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 182 Preliminary 2010 Microchip Technology Inc.
TABLE 20-5: SUMMARY OF REGISTERS ASSOCIATED WITH TIMER1
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA — — — ANSA4 — ANSA2 ANSA1 ANSA0 122
CCP1CON P1M1 P1M0 DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 221
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register 172*
TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register 172*
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
T1CON TMR1CS1 TMR1CS0 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC —TMR1ON
180
T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/
DONE
T1GVAL T1GSS1 T1GSS0 181
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 183
PIC12F/LF1822/16F/LF1823
NOTES:
PIC12F/LF1822/16F/LF1823
DS41413A-page 184 Preliminary 2010 Microchip Technology Inc.
21.0 TIMER2 MODULE
The Timer2 module incorporate the following features:
• 8-bit Timer and Period registers (TMR2 and PR2,
respectively)
• Readable and writable (both registers)
• Software programmable prescaler (1:1, 1:4, 1:16,
and 1:64)
• Software programmable postscaler (1:1 to 1:16)
• Interrupt on TMR2 match with PR2, respectively
• Optional use as the shift clock for the MSSP1
modules (Timer2 only)
See Figure 21-1 for a block diagram of Timer2.
FIGURE 21-1: TIMER2 BLOCK DIAGRAM
Comparator
TMRx Sets Flag
TMR2
Outp2t
Reset
Postscaler
Prescaler
PR2
2
FOSC/4
1:1 to 1:16
1:1, 1:4, 1:16, 1:64
EQ
4
bit TMR2IF
T2OUTPS<3:0>
T2CKPS<1:0>
2010 Microchip Technology Inc. Preliminary DS41413A-page 185
PIC12F/LF1822/16F/LF1823
21.1 Timer2 Operation
The clock input to the Timer2 modules is the system
instruction clock (FOSC/4).
TMR2 increments from 00h on each clock edge.
A 4-bit counter/prescaler on the clock input allows direct
input, divide-by-4 and divide-by-16 prescale options.
These options are selected by the prescaler control bits,
T2CKPS<1:0> of the T2CON register. The value of
TMR2 is compared to that of the Period register, PR2, on
each clock cycle. When the two values match, the
comparator generates a match signal as the timer
output. This signal also resets the value of TMR2 to 00h
on the next cycle and drives the output
counter/postscaler (see Section 21.2 “Timer2
Interrupt”).
The TMR2 and PR2 registers are both directly readable
and writable. The TMR2 register is cleared on any
device Reset, whereas the PR2 register initializes to
FFh. Both the prescaler and postscaler counters are
cleared on the following events:
• a write to the TMR2 register
• a write to the T2CON register
• Power-on Reset (POR)
• Brown-out Reset (BOR)
•MCLR
Reset
• Watchdog Timer (WDT) Reset
• Stack Overflow Reset
• Stack Underflow Reset
•RESET Instruction
21.2 Timer2 Interrupt
Timer2 can also generate an optional device interrupt.
The Timer2 output signal (TMR2-to-PR2 match)
provides the input for the 4-bit counter/postscaler. This
counter generates the TMR2 match interrupt flag which
is latched in TMR2IF of the PIR1 register. The interrupt
is enabled by setting the TMR2 Match Interrupt Enable
bit, TMR2IE of the PIE1 register.
A range of 16 postscale options (from 1:1 through 1:16
inclusive) can be selected with the postscaler control
bits, T2OUTPS<3:0>, of the T2CON register.
21.3 Timer2 Output
The unscaled output of TMR2 is available primarily to
the CCP1 module, where it is used as a time base for
operations in PWM mode.
Timer2 can be optionally used as the shift clock source
for the MSSP1 module operating in SPI mode.
Additional information is provided in Section 24.1
“Master SSP (MSSP1) Module Overview”
21.4 Timer2 Operation During Sleep
The Timer2 timers cannot be operated while the
processor is in Sleep mode. The contents of the TMR2
and PR2 registers will remain unchanged while the
processor is in Sleep mode.
Note: TMR2 is not cleared when T2CON is
written.
PIC12F/LF1822/16F/LF1823
DS41413A-page 186 Preliminary 2010 Microchip Technology Inc.
REGISTER 21-1: T2CON: TIMER2 CONTROL REGISTER
U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
— TOUTPS<3:0> TMR2ON T2CKPS<1:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 Unimplemented: Read as ‘0’
bit 6-3 TOUTPS<3:0>: Timer Output Postscaler Select bits
0000 = 1:1 Postscaler
0001 = 1:2 Postscaler
0010 = 1:3 Postscaler
0011 = 1:4 Postscaler
0100 = 1:5 Postscaler
0101 = 1:6 Postscaler
0110 = 1:7 Postscaler
0111 = 1:8 Postscaler
1000 = 1:9 Postscaler
1001 = 1:10 Postscaler
1010 = 1:11 Postscaler
1011 = 1:12 Postscaler
1100 = 1:13 Postscaler
1101 = 1:14 Postscaler
1110 = 1:15 Postscaler
1111 = 1:16 Postscaler
bit 2 TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
bit 1-0 T2CKPS<1:0>: Timer2 Clock Prescale Select bits
00 =Prescaler is 1
01 =Prescaler is 4
10 = Prescaler is 16
11 = Prescaler is 64
2010 Microchip Technology Inc. Preliminary DS41413A-page 187
PIC12F/LF1822/16F/LF1823
TABLE 21-1: SUMMARY OF REGISTERS ASSOCIATED WITH TIMER2
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CCP1CON P1M<1:0> DC1B<1:0> CCP1M<3:0> 221
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 92
PR2 Timer2 Module Period Register 184*
T2CON — TOUTPS<3:0> TMR2ON T2CKPS1 T2CKPS0 186
TMR2 Holding Register for the 8-bit TMR2 Register 184*
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Timer2 module.
* Page provides register information.
PIC12F/LF1822/16F/LF1823
DS41413A-page 188 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 189
PIC12F/LF1822/16F/LF1823
22.0 DATA SIGNAL MODULATOR
The Data Signal Modulator (DSM) is a peripheral which
allows the user to mix a data stream, also known as a
modulator signal, with a carrier signal to produce a
modulated output.
Both the carrier and the modulator signals are supplied
to the DSM module either internally, from the output of
a peripheral, or externally through an input pin.
The modulated output signal is generated by perform-
ing a logical “AND” operation of both the carrier and
modulator signals and then provided to the MDOUT pin.
The carrier signal is comprised of two distinct and sep-
arate signals. A carrier high (CARH) signal and a car-
rier low (CARL) signal. During the time in which the
modulator (MOD) signal is in a logic high state, the
DSM mixes the carrier high signal with the modulator
signal. When the modulator signal is in a logic low
state, the DSM mixes the carrier low signal with the
modulator signal.
Using this method, the DSM can generate the following
types of Key Modulation schemes:
• Frequency-Shift Keying (FSK)
• Phase-Shift Keying (PSK)
• On-Off Keying (OOK)
Additionally, the following features are provided within
the DSM module:
• Carrier Synchronization
• Carrier Source Polarity Select
• Carrier Source Pin Disable
• Programmable Modulator Data
• Modulator Source Pin Disable
• Modulated Output Polarity Select
• Slew Rate Control
Figure 22-1 shows a Simplified Block Diagram of the
Data Signal Modulator peripheral.
FIGURE 22-1: SIMPLIFIED BLOCK DIAGRAM OF THE DATA SIGNAL MODULATOR
D
Q
MDBIT
MDMIN
CCP1
Comparator C1
Comparator C2(1)
Reserved
0000
0001
0010
0011
0101
0110
0111
1000
0011
1001
1010
No Channel
Selected
VSS
MDCIN1
MDCIN2
CLKR
CCP1
Reserved
0000
0001
0010
0011
0100
0101
0110
1111
*
*
No Channel
Selected
VSS
MDCIN1
MDCIN2
CLKR
CCP1
Reserved
0000
0001
0010
0011
0100
0101
0110
0111
1000
1111
*
*
No Channel
Selected
MDCH<3:0>
MDMS<3:0>
MDCL<3:0>
1111
*
*
MSSP1 SDO1
Reserved
EUSART
SYNC
MDCHPOL
MDCLPOL
D
Q1
0
SYNC
1
0
MDCHSYNC
MDCLSYNC
MDOUT
MDOPOL
CARH
CARL
EN
MDEN
Data Signal
Modulator
MOD
MDOE
*
*
Reserved
No Channel
Selected *
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 190 Preliminary 2010 Microchip Technology Inc.
22.1 DSM Operation
The DSM module can be enabled by setting the MDEN
bit in the MDCON register. Clearing the MDEN bit in the
MDCON register, disables the DSM module by auto-
matically switching the carrier high and carrier low sig-
nals to the VSS signal source. The modulator signal
source is also switched to the MDBIT in the MDCON
register. This not only assures that the DSM module is
inactive, but that it is also consuming the least amount
of current.
The values used to select the carrier high, carrier low,
and modulator sources held by the Modulation Source,
Modulation High Carrier, and Modulation Low Carrier
control registers are not affected when the MDEN bit is
cleared and the DSM module is disabled. The values
inside these registers remain unchanged while the
DSM is inactive. The sources for the carrier high, car-
rier low and modulator signals will once again be
selected when the MDEN bit is set and the DSM
module is again enabled and active.
The modulated output signal can be disabled without
shutting down the DSM module. The DSM module will
remain active and continue to mix signals, but the out-
put value will not be sent to the MDOUT pin. During the
time that the output is disabled, the MDOUT pin will
remain low. The modulated output can be disabled by
clearing the MDOE bit in the MDCON register.
22.2 Modulator Signal Sources
The modulator signal can be supplied from the
following sources:
• CCP1 Signal
• MSSP1 SDO1 Signal (SPI Mode Only)
• Comparator C1 Signal
• Comparator C2 Signal (PIC16F/LF1823 only)
• EUSART TX Signal
• External Signal on MDMIN1 pin
• MDBIT bit in the MDCON register
The modulator signal is selected by configuring the
MDMS <3:0> bits in the MDSRC register.
22.3 Carrier Signal Sources
The carrier high signal and carrier low signal can be
supplied from the following sources:
• CCP1 Signal
• Reference Clock Module Signal
• External Signal on MDCIN1 pin
• External Signal on MDCIN2 pin
•V
SS
The carrier high signal is selected by configuring the
MDCH <3:0> bits in the MDCARH register. The carrier
low signal is selected by configuring the MDCL <3:0>
bits in the MDCARL register.
22.4 Carrier Synchronization
During the time when the DSM switches between car-
rier high and carrier low signal sources, the carrier data
in the modulated output signal can become truncated.
To prevent this, the carrier signal can be synchronized
to the modulator signal. When synchronization is
enabled, the carrier pulse that is being mixed at the
time of the transition is allowed to transition low before
the DSM switches over to the next carrier source.
Synchronization is enabled separately for the carrier
high and carrier low signal sources. Synchronization for
the carrier high signal can be enabled by setting the
MDCHSYNC bit in the MDCARH register. Synchroniza-
tion for the carrier low signal can be enabled by setting
the MDCLSYNC bit in the MDCARL register.
Figure 22-1 through Figure 22-5 show timing diagrams
of using various synchronization methods.
2010 Microchip Technology Inc. Preliminary DS41413A-page 191
PIC12F/LF1822/16F/LF1823
FIGURE 22-2: ON OFF KEYING (OOK) SYNCHRONIZATION
EXAMPLE 22-1: NO SYNCHRONIZATION (MDSHSYNC = 0, MDCLSYNC = 0)
FIGURE 22-3: CARRIER HIGH SYNCHRONIZATION (MDSHSYNC = 1, MDCLSYNC = 0)
Carrier Low (CARL)
MDCHSYNC = 1
MDCLSYNC = 0
MDCHSYNC = 1
MDCLSYNC = 1
MDCHSYNC = 0
MDCLSYNC = 0
MDCHSYNC = 0
MDCLSYNC = 1
Carrier High (CARH)
Modulator (MOD)
MDCHSYNC = 0
MDCLSYNC = 0
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier CARH CARL CARL
CARH
State
MDCHSYNC = 1
MDCLSYNC = 0
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier
CARH CARL CARL
CARH
State
both both
PIC12F/LF1822/16F/LF1823
DS41413A-page 192 Preliminary 2010 Microchip Technology Inc.
FIGURE 22-4: CARRIER LOW SYNCHRONIZATION (MDSHSYNC = 0, MDCLSYNC = 1)
FIGURE 22-5: FULL SYNCHRONIZATION (MDSHSYNC = 1, MDCLSYNC = 1)
MDCHSYNC = 0
MDCLSYNC = 1
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier CARH CARL CARL
CARH
State
MDCHSYNC = 1
MDCLSYNC = 1
Modulator (MOD)
Carrier High (CARH)
Carrier Low (CARL)
Active Carrier CARH CARL CARL
CARH
State
Falling edges
used to sync
2010 Microchip Technology Inc. Preliminary DS41413A-page 193
PIC12F/LF1822/16F/LF1823
22.5 CARRIER SOURCE POLARITY
SELECT
The signal provided from any selected input source for
the carrier high and carrier low signals can be inverted.
Inverting the signal for the carrier high source is
enabled by setting the MDCHPOL bit of the MDCARH
register. Inverting the signal for the carrier low source is
enabled by setting the MDCLPOL bit of the MDCARL
register.
22.6 CARRIER SOURCE PIN DISABLE
Some peripherals assert control over their correspond-
ing output pin when they are enabled. For example,
when the CCP1 module is enabled, the output of CCP1
is connected to the CCP1 pin.
This default connection to a pin can be disabled by set-
ting the MDCHODIS bit in the MDCARH register for the
carrier high source and the MDCLODIS bit in the
MDCARL register for the carrier low source.
22.7 PROGRAMMABLE MODULATOR
DATA
The MDBIT of the MDCON register can be selected as
the source for the modulator signal. This gives the user
the ability to program the value used for modulation.
22.8 MODULATOR SOURCE PIN
DISABLE
The modulator source default connection to a pin can
be disabled by setting the MDMSODIS bit in the
MDSRC register.
22.9 MODULATED OUTPUT POLARITY
The modulated output signal provided on the MDOUT
pin can also be inverted. Inverting the modulated out-
put signal is enabled by setting the MDOPOL bit of the
MDCON register.
22.10 SLEW RATE CONTROL
The slew rate limitation on the output port pin can be
disabled. The slew rate limitation can be removed by
clearing the MDSLR bit in the MDCON register.
22.11 OPERATION IN SLEEP MODE
The DSM module is not affected by Sleep mode. The
DSM can still operate during Sleep, if the Carrier and
Modulator input sources are also still operable during
Sleep.
22.12 Effects of a Reset
Upon any device Reset, the Data Signal Modulator
module is disabled. The user’s firmware is responsible
for initializing the module before enabling the output.
The registers are reset to their default values.
PIC12F/LF1822/16F/LF1823
DS41413A-page 194 Preliminary 2010 Microchip Technology Inc.
REGISTER 22-1: MDCON: MODULATION CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-1/1 R/W-0/0 R/W-0/0 U-0 U-0 R/W-0/0
MDEN MDOE MDSLR MDOPOL MDOUT ——MDBIT
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 MDEN: Modulator Module Enable bit
1 = Modulator module is enabled and mixing input signals
0 = Modulator module is disabled and has no output
bit 6 MDOE: Modulator Module Pin Output Enable bit
1 = Modulator pin output enabled
0 = Modulator pin output disabled
bit 5 MDSLR: MDOUT Pin Slew Rate Limiting bit
1 = MDOUT pin slew rate limiting enabled
0 = MDOUT pin slew rate limiting disabled
bit 4 MDOPOL: Modulator Output Polarity Select bit
1 = Modulator output signal is inverted
0 = Modulator output signal is not inverted
bit 3 MDOUT: Modulator Output bit
Displays the current output value of the Modulator module.(1)
bit 2-1 Unimplemented: Read as ‘0’
bit 0 MDBIT: Allows software to manually set modulation source input to module(1)
Note 1: The modulated output frequency can be greater and asynchronous from the clock that updates this
register bit, the bit value may not be valid for higher speed modulator or carrier signals.
2: MDBIT must be selected as the modulation source in the MDSRC register for this operation.
2010 Microchip Technology Inc. Preliminary DS41413A-page 195
PIC12F/LF1822/16F/LF1823
REGISTER 22-2: MDSRC: MODULATION SOURCE CONTROL REGISTER
R/W-x/u U-0 U-0 U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u
MDMSODIS — — —MDMS<3:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 MDMSODIS: Modulation Source Output Disable
1 = Output signal driving the peripheral output pin (selected by MDMS<3:0>) is disabled
0 = Output signal driving the peripheral output pin (selected by MDMS<3:0>) is enabled
bit 6-4 Unimplemented: Read as ‘0’
bit 3-0 MDMS<3:0> Modulation Source Selection bits
1111 = Reserved. No channel connected.
1110 = Reserved. No channel connected.
1101 = Reserved. No channel connected.
1100 = Reserved. No channel connected.
1011 = Reserved. No channel connected.
1010 = EUSART TX output
1001 = Reserved. No channel selected.
1000 = MSSP1 SDOx output
0111 = Comparator 2 output (PIC16F/LF1823 only. PIC12F/LF1822; Reserved, no channel connected.)
0110 = Comparator 1 output
0101 = Reserved. No channel connected.
0100 = Reserved. No channel connected.
0011 = Reserved. No channel connected.
0010 = CCP1 output (PWM Output mode only)
0001 = MDMIN port pin
0000 = MDBIT bit of MDCON register is modulation source
Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not synchronized.
PIC12F/LF1822/16F/LF1823
DS41413A-page 196 Preliminary 2010 Microchip Technology Inc.
REGISTER 22-3: MDCARH: MODULATION HIGH CARRIER CONTROL REGISTER
R/W-x/u R/W-x/u R/W-x/u U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u
MDCHODIS MDCHPOL MDCHSYNC — MDCH<3:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 MDCHODIS: Modulator High Carrier Output Disable bit
1 = Output signal driving the peripheral output pin (selected by MDCH<3:0>) is disabled
0 = Output signal driving the peripheral output pin (selected by MDCH<3:0>) is enabled
bit 6 MDCHPOL: Modulator High Carrier Polarity Select bit
1 = Selected high carrier signal is inverted
0 = Selected high carrier signal is not inverted
bit 5 MDCHSYNC: Modulator High Carrier Synchronization Enable bit
1 = Modulator waits for a falling edge on the high time carrier signal before allowing a switch to the
low time carrier
0 = Modulator Output is not synchronized to the high time carrier signal(1)
bit 4 Unimplemented: Read as ‘0’
bit 3-0 MDCH<3:0> Modulator Data High Carrier Selection bits (1)
1111 = Reserved. No channel connected.
•
•
•
1000 = Reserved. No channel connected.
0111 = Reserved. No channel connected.
0110 = Reserved. No channel connected.
0101 = Reserved. No channel connected.
0100 = CCP1 output (PWM Output mode only)
0011 = Reference Clock module signal
0010 = Reserved. No channel connected.
0001 = MDCIN1 port pin
0000 =V
SS
Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not synchronized.
2010 Microchip Technology Inc. Preliminary DS41413A-page 197
PIC12F/LF1822/16F/LF1823
TABLE 22-1: SUMMARY OF REGISTERS ASSOCIATED WITH DATA SIGNAL MODULATOR MODE
REGISTER 22-4: MDCARL: MODULATION LOW CARRIER CONTROL REGISTER
R/W-x/u R/W-x/u R/W-x/u U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u
MDCLODIS MDCLPOL MDCLSYNC — MDCL<3:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 MDCLODIS: Modulator Low Carrier Output Disable bit
1 = Output signal driving the peripheral output pin (selected by MDCL<3:0> of the MDCARL register)
is disabled
0 = Output signal driving the peripheral output pin (selected by MDCL<3:0> of the MDCARL register)
is enabled
bit 6 MDCLPOL: Modulator Low Carrier Polarity Select bit
1 = Selected low carrier signal is inverted
0 = Selected low carrier signal is not inverted
bit 5 MDCLSYNC: Modulator Low Carrier Synchronization Enable bit
1 = Modulator waits for a falling edge on the low time carrier signal before allowing a switch to the high
time carrier
0 = Modulator Output is not synchronized to the low time carrier signal(1)
bit 4 Unimplemented: Read as ‘0’
bit 3-0 MDCL<3:0> Modulator Data High Carrier Selection bits (1)
1111 = Reserved. No channel connected.
•
•
•
0101 = Reserved. No channel connected.
0100 = CCP1 output (PWM Output mode only)
0011 = Reference Clock module signal
0010 = Reserved. No channel connected.
0001 = MDCIN1 port pin
0000 =V
SS
Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not synchronized.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
MDCARH MDCHODIS MDCHPOL MDCHSYNC —
MDCH<3:0>
196
MDCARL MDCLODIS MDCLPOL MDCLSYNC —
MDCL<3:0>
197
MDCON MDEN MDOE MDSLR MDOPOL MDOUT — —
MDBIT
194
MDSRC MDMSODIS — — —
MDMS<3:0>
195
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used in the Data Signal Modulator mode.
PIC12F/LF1822/16F/LF1823
DS41413A-page 198 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 199
PIC12F/LF1822/16F/LF1823
23.0 CAPTURE/COMPARE/PWM
MODULES
The Capture/Compare/PWM module is a peripheral
which allows the user to time and control different
events, and to generate Pulse-Width Modulation
(PWM) signals. In Capture mode, the peripheral allows
the timing of the duration of an event. The Compare
mode allows the user to trigger an external event when
a predetermined amount of time has expired. The
PWM mode can generate Pulse-Width Modulated
signals of varying frequency and duty cycle.
This family of devices contains one Enhanced Capture/
Compare/PWM module (ECCP1).
The Full-Bridge ECCP module has four available I/O
pins, while the Half-Bridge ECCP module only has two.
See Table 23-1.
TABLE 23-1: PWM RESOURCES
Device Name ECCP1
PIC12F/LF1822 Enhanced PWM Half-Bridge
PIC16F/LF1823 Enhanced PWM Full-Bridge
PIC12F/LF1822/16F/LF1823
DS41413A-page 200 Preliminary 2010 Microchip Technology Inc.
23.1 Capture Mode
Capture mode makes use of the 16-bit Timer1
resource. When an event occurs on the CCP1 pin, the
16-bit CCPR1H:CCPR1L register pair captures and
stores the 16-bit value of the TMR1H:TMR1L register
pair, respectively. An event is defined as one of the
following and is configured by the CCP1M<3:0> bits of
the CCP1CON register:
• Every falling edge
• Every rising edge
• Every 4th rising edge
• Every 16th rising edge
When a capture is made, the Interrupt Request Flag bit
CCP1IF of the PIR1 register is set. The interrupt flag
must be cleared in software. If another capture occurs
before the value in the CCPR1H, CCPR1L register pair
is read, the old captured value is overwritten by the new
captured value.
Figure 23-1 shows a simplified diagram of the Capture
operation.
23.1.1 CCP1 PIN CONFIGURATION
In Capture mode, the CCP1 pin should be configured
as an input by setting the associated TRIS control bit.
Also, the CCP1 pin function may be moved to
alternative pins using the APFCON register. Refer to
Section 12.1 “Alternate Pin Function” for more
details.
FIGURE 23-1: CAPTURE MODE
OPERATION BLOCK
DIAGRAM
23.1.2 TIMER1 MODE RESOURCE
Timer1 must be running in Timer mode or Synchronized
Counter mode for the CCP1 module to use the capture
feature. In Asynchronous Counter mode, the capture
operation may not work.
See Section 20.0 “Timer1 Module with Gate Control”
for more information on configuring Timer1.
23.1.3 SOFTWARE INTERRUPT MODE
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep the
CCP1IE interrupt enable bit of the PIE1 register clear to
avoid false interrupts. Additionally, the user should
clear the CCP1IF interrupt flag bit of the PIR1 register
following any change in Operating mode.
23.1.4 CCP1 PRESCALER
There are four prescaler settings specified by the
CCP1M<3:0> bits of the CCP1CON register.
Whenever the CCP1 module is turned off, or the CCP1
module is not in Capture mode, the prescaler counter
is cleared. Any Reset will clear the prescaler counter.
Switching from one capture prescaler to another does not
clear the prescaler and may generate a false interrupt. To
avoid this unexpected operation, turn the module off by
clearing the CCP1CON register before changing the
prescaler. Example 23-1 demonstrates the code to
perform this function.
EXAMPLE 23-1: CHANGING BETWEEN
CAPTURE PRESCALERS
Note: If the CCP1 pin is configured as an output,
a write to the port can cause a capture
condition.
CCPR1H CCPR1L
TMR1H TMR1L
Set Flag bit CCP1IF
(PIR1 register)
Capture
Enable
CCP1M<3:0>
Prescaler
1, 4, 16
and
Edge Detect
pin
CCP1
System Clock (FOSC)
Note: Clocking Timer1 from the system clock
(FOSC) should not be used in Capture
mode. In order for Capture mode to
recognize the trigger event on the CCP1
pin, Timer1 must be clocked from the
instruction clock (FOSC/4) or from an
external clock source.
BANKSEL CCP1CON ;Set Bank bits to point
;to CCP1CON
CLRF CCP1CON ;Turn CCP1 module off
MOVLW NEW_CAPT_PS ;Load the W reg with
;the new prescaler
;move value and CCP1 ON
MOVWF CCP1CON ;Load CCP1CON with this
;value
2010 Microchip Technology Inc. Preliminary DS41413A-page 201
PIC12F/LF1822/16F/LF1823
23.1.5 CAPTURE DURING SLEEP
Capture mode depends upon the Timer1 module for
proper operation. There are two options for driving the
Timer1 module in Capture mode. It can be driven by the
instruction clock (FOSC/4), or by an external clock source.
When Timer1 is clocked by FOSC/4, Timer1 will not
increment during Sleep. When the device wakes from
Sleep, Timer1 will continue from its previous state.
Capture mode will operate during Sleep when Timer1
is clocked by an external clock source.
TABLE 23-2: SUMMARY OF REGISTERS ASSOCIATED WITH CAPTURE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CCP1CON P1M<1:0> DC1B<1:0> CCP1M<3:0> 221
CCPR1L Capture/Compare/PWM Register x Low Byte (LSB) 200
CCPR1H Capture/Compare/PWM Register x High Byte (MSB) 200
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE — — —91
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF — — —93
T1CON TMR1CS<1:0> T1CKPS<1:0> T1OSCEN T1SYNC —TMR1ON
180
T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/DONE T1GVAL T1GSS<1:0> 181
TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register 172
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register 172
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) ——TRISC5TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = Unimplemented location, read as ‘0’. Shaded cells are not used by Capture mode.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 202 Preliminary 2010 Microchip Technology Inc.
23.2 Compare Mode
Compare mode makes use of the 16-bit Timer1
resource. The 16-bit value of the CCPR1H:CCPR1L
register pair is constantly compared against the 16-bit
value of the TMR1H:TMR1L register pair. When a
match occurs, one of the following events can occur:
• Toggle the CCP1 output
• Set the CCP1 output
• Clear the CCP1 output
• Generate a Special Event Trigger
• Generate a Software Interrupt
The action on the pin is based on the value of the
CCP1M<3:0> control bits of the CCP1CON register. At
the same time, the interrupt flag CCP1IF bit is set.
All Compare modes can generate an interrupt.
Figure 23-2 shows a simplified diagram of the
Compare operation.
FIGURE 23-2: COMPARE MODE
OPERATION BLOCK
DIAGRAM
23.2.1 CCP1 PIN CONFIGURATION
The user must configure the CCP1 pin as an output by
clearing the associated TRIS bit.
Also, the CCP1 pin function may be moved to
alternative pins using the APFCON register. Refer to
Section 12.1 “Alternate Pin Function” for more
details.
23.2.2 TIMER1 MODE RESOURCE
In Compare mode, Timer1 must be running in either
Timer mode or Synchronized Counter mode. The
compare operation may not work in Asynchronous
Counter mode.
See Section 20.0 “Timer1 Module with Gate Control”
for more information on configuring Timer1.
23.2.3 SOFTWARE INTERRUPT MODE
When Generate Software Interrupt mode is chosen
(CCP1M<3:0> = 1010), the CCP1 module does not
assert control of the CCP1 pin (see the CCP1CON
register).
23.2.4 SPECIAL EVENT TRIGGER
When Special Event Trigger mode is chosen
(CCP1M<3:0> = 1011), the CCP1 module does the
following:
• Resets Timer1
• Starts an ADC conversion if ADC is enabled
The CCP1 module does not assert control of the CCP1
pin in this mode.
The Special Event Trigger output of the CCP1 occurs
immediately upon a match between the TMR1H,
TMR1L register pair and the CCPR1H, CCPR1L
register pair. The TMR1H, TMR1L register pair is not
reset until the next rising edge of the Timer1 clock. The
Special Event Trigger output starts an A/D conversion
(if the A/D module is enabled). This allows the
CCPR1H, CCPR1L register pair to effectively provide a
16-bit programmable period register for Timer1.
23.2.5 COMPARE DURING SLEEP
The Compare mode is dependent upon the system
clock (FOSC) for proper operation. Since FOSC is shut
down during Sleep mode, the Compare mode will not
function properly during Sleep.
Note: Clearing the CCP1CON register will force
the CCP1 compare output latch to the
default low level. This is not the PORT I/O
data latch.
CCPR1H CCPR1L
TMR1H TMR1L
Comparator
QS
R
Output
Logic
Special Event Trigger
Set CCP1IF Interrupt Flag
(PIR1)
Match
TRIS
CCP1M<3:0>
Mode Select
Output Enable
Pin
Special Event Trigger will:
• CCP1: Reset Timer1, but not set interrupt flag bit TMR1IF
and set bit GO/DONE (ADCON0<1>).
CCP1
4
Note: Clocking Timer1 from the system clock
(FOSC) should not be used in Capture
mode. In order for Capture mode to
recognize the trigger event on the CCP1
pin, TImer1 must be clocked from the
instruction clock (FOSC/4) or from an
external clock source.
Note 1: The Special Event Trigger from the CCP1
module does not set interrupt flag bit
TMR1IF of the PIR1 register.
2: Removing the match condition by
changing the contents of the CCPR1H
and CCPR1L register pair, between the
clock edge that generates the Special
Event Trigger and the clock edge that
generates the Timer1 Reset, will preclude
the Reset from occurring.
2010 Microchip Technology Inc. Preliminary DS41413A-page 203
PIC12F/LF1822/16F/LF1823
TABLE 23-3: SUMMARY OF REGISTERS ASSOCIATED WITH COMPARE
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CCP1CON P1M<1:0> DC1B<1:0> CCP1M<3:0> 221
CCPR1L Capture/Compare/PWM Register 1 Low Byte (LSB) 200
CCPR1H Capture/Compare/PWM Register 1 High Byte (MSB) 200
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE — — — 91
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF — — — 93
T1CON TMR1CS<1:0> T1CKPS<1:0> T1OSCEN T1SYNC —TMR1ON
180
T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/DONE T1GVAL T1GSS<1:0> 181
TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register 172
TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register 172
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) ——TRISC5TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = Unimplemented location, read as ‘0’. Shaded cells are not used by Compare mode.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 204 Preliminary 2010 Microchip Technology Inc.
23.3 PWM Overview
Pulse-Width Modulation (PWM) is a scheme that
provides power to a load by switching quickly between
fully on and fully off states. The PWM signal resembles
a square wave where the high portion of the signal is
considered the on state and the low portion of the signal
is considered the off state. The high portion, also known
as the pulse width, can vary in time and is defined in
steps. A larger number of steps applied, which
lengthens the pulse width, also supplies more power to
the load. Lowering the number of steps applied, which
shortens the pulse width, supplies less power. The
PWM period is defined as the duration of one complete
cycle or the total amount of on and off time combined.
PWM resolution defines the maximum number of steps
that can be present in a single PWM period. A higher
resolution allows for more precise control of the pulse
width time and in turn the power that is applied to the
load.
The term duty cycle describes the proportion of the on
time to the off time and is expressed in percentages,
where 0% is fully off and 100% is fully on. A lower duty
cycle corresponds to less power applied and a higher
duty cycle corresponds to more power applied.
Figure 23-3 shows a typical waveform of the PWM
signal.
23.3.1 STANDARD PWM OPERATION
The standard PWM mode generates a Pulse-Width
modulation (PWM) signal on the CCP1 pin with up to 10
bits of resolution. The period, duty cycle, and resolution
are controlled by the following registers:
• PR2 registers
• T2CON registers
• CCPR1L registers
• CCP1CON registers
Figure 23-4 shows a simplified block diagram of PWM
operation.
FIGURE 23-3: CCP1 PWM OUTPUT
SIGNAL
FIGURE 23-4: SIMPLIFIED PWM BLOCK
DIAGRAM
Note 1: The corresponding TRIS bit must be
cleared to enable the PWM output on the
CCP1 pin.
2: Clearing the CCP1CON register will
relinquish control of the CCP1 pin.
Period
Pulse Width
TMR2 = 0
TMR2 = CCPR1H:CCP1CON<5:4>
TMR2 = PR2
CCPR1L
CCPR1H(2) (Slave)
Comparator
TMR2
PR2
(1)
RQ
S
Duty Cycle Registers CCP1CON<5:4>
Clear Timer,
toggle CCP1 pin and
latch duty cycle
Note 1: The 8-bit timer TMR2 register is concatenated
with the 2-bit internal system clock (FOSC), or
2 bits of the prescaler, to create the 10-bit time
base.
2: In PWM mode, CCPR1H is a read-only register.
TRIS
CCP1
Comparator
2010 Microchip Technology Inc. Preliminary DS41413A-page 205
PIC12F/LF1822/16F/LF1823
23.3.2 SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the CCP1 module for standard PWM operation:
1. Disable the CCP1 pin output driver by setting
the associated TRIS bit.
2. Load the PR2 register with the PWM period
value.
3. Configure the CCP1 module for the PWM mode
by loading the CCP1CON register with the
appropriate values.
4. Load the CCPR1L register and the DC1B1 bits
of the CCP1CON register, with the PWM duty
cycle value.
5. Configure and start Timer2:
• Clear the TMR2IF interrupt flag bit of the
PIR1 register. See Note below.
• Configure the T2CKPS bits of the T2CON
register with the Timer prescale value.
• Enable the Timer by setting the TMR2ON
bit of the T2CON register.
6. Enable PWM output pin:
• Wait until the Timer overflows and the
TMR2IF bit of the PIR1 register is set. See
Note below.
• Enable the CCP1 pin output driver by clear-
ing the associated TRIS bit.
23.3.3 PWM PERIOD
The PWM period is specified by the PR2 register of
Timer2. The PWM period can be calculated using the
formula of Equation 23-1.
EQUATION 23-1: PWM PERIOD
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
•TMR2 is cleared
• The CCP1 pin is set. (Exception: If the PWM duty
cycle = 0%, the pin will not be set.)
• The PWM duty cycle is latched from CCPR1L into
CCPR1H.
23.3.4 PWM DUTY CYCLE
The PWM duty cycle is specified by writing a 10-bit
value to multiple registers: CCPR1L register and
DC1B<1:0> bits of the CCP1CON register. The
CCPR1L contains the eight MSbs and the DC1B<1:0>
bits of the CCP1CON register contain the two LSbs.
CCPR1L and DC1B<1:0> bits of the CCP1CON
register can be written to at any time. The duty cycle
value is not latched into CCPR1H until after the period
completes (i.e., a match between PR2 and TMR2
registers occurs). While using the PWM, the CCPR1H
register is read-only.
Equation 23-2 is used to calculate the PWM pulse
width.
Equation 23-3 is used to calculate the PWM duty cycle
ratio.
EQUATION 23-2: PULSE WIDTH
EQUATION 23-3: DUTY CYCLE RATIO
The CCPR1H register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitchless PWM operation.
The 8-bit timer TMR2 register is concatenated with
either the 2-bit internal system clock (FOSC), or 2 bits of
the prescaler, to create the 10-bit time base. The system
clock is used if the Timer2 prescaler is set to 1:1.
When the 10-bit time base matches the CCPR1H and
2-bit latch, then the CCP1 pin is cleared (see
Figure 23-4).
Note: In order to send a complete duty cycle and
period on the first PWM output, the above
steps must be included in the setup
sequence. If it is not critical to start with a
complete PWM signal on the first output,
then step 6 may be ignored.
PWM Period PR21+4TOSC =
(TMR2 Prescale Value)
Note 1: TOSC = 1/FOSC
Note: The Timer postscaler (see Section 21.1
“Timer2 Operation”) is not used in the
determination of the PWM frequency.
Pulse Width CCPR1L:CCP1CON<5:4>
=
TOSC
(TMR2 Prescale Value)
Duty Cycle Ratio CCPRxL:CCPxCON<5:4>
4 PRx 1+
-----------------------------------------------------------------------=
PIC12F/LF1822/16F/LF1823
DS41413A-page 206 Preliminary 2010 Microchip Technology Inc.
23.3.5 PWM RESOLUTION
The resolution determines the number of available duty
cycles for a given period. For example, a 10-bit resolution
will result in 1024 discrete duty cycles, whereas an 8-bit
resolution will result in 256 discrete duty cycles.
The maximum PWM resolution is 10 bits when PR2 is
255. The resolution is a function of the PR2 register
value as shown by Equation 23-4.
EQUATION 23-4: PWM RESOLUTION
TABLE 23-4: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 32 MHz)
TABLE 23-5: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
TABLE 23-6: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz)
Note: If the pulse width value is greater than the
period the assigned PWM pin(s) will
remain unchanged.
Resolution 4PR21+log
2log
------------------------------------------ bits=
PWM Frequency 1.95 kHz 7.81 kHz 31.25 kHz 125 kHz 250 kHz 333.3 kHz
Timer Prescale (1, 4, 16) 16 4 1 1 1 1
PR2 Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 10 10 10 8 7 6.6
PWM Frequency 1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
Timer Prescale (1, 4, 16) 16 4 1 1 1 1
PR2 Value 0xFF 0xFF 0xFF 0x3F 0x1F 0x17
Maximum Resolution (bits) 10 10 10 8 7 6.6
PWM Frequency 1.22 kHz 4.90 kHz 19.61 kHz 76.92 kHz 153.85 kHz 200.0 kHz
Timer Prescale (1, 4, 16) 16 4 1 1 1 1
PR2 Value 0x65 0x65 0x65 0x19 0x0C 0x09
Maximum Resolution (bits) 8 8 8 6 5 5
2010 Microchip Technology Inc. Preliminary DS41413A-page 207
PIC12F/LF1822/16F/LF1823
23.3.6 OPERATION IN SLEEP MODE
In Sleep mode, the TMR2 register will not increment
and the state of the module will not change. If the CCP1
pin is driving a value, it will continue to drive that value.
When the device wakes up, TMR2 will continue from its
previous state.
23.3.7 CHANGES IN SYSTEM CLOCK
FREQUENCY
The PWM frequency is derived from the system clock
frequency. Any changes in the system clock frequency
will result in changes to the PWM frequency. See
Section 5.0 “Oscillator Module (With Fail-Safe
Clock Monitor)” for additional details.
23.3.8 EFFECTS OF RESET
Any Reset will force all ports to Input mode and the
CCP registers to their Reset states.
TABLE 23-7: SUMMARY OF REGISTERS ASSOCIATED WITH STANDARD PWM
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CCP1CON P1M<1:0> DC1B<1:0> CCP1M<3:0> 221
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
PR2 Timer2 Period Register 184*
T2CON — T2OUTPS<3:0> TMR2ON T2CKPS<:0>1 186
TMR2 Timer2 Module Register 184
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) —— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = Unimplemented location, read as ‘0’. Shaded cells are not used by the PWM.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 208 Preliminary 2010 Microchip Technology Inc.
23.4 PWM (Enhanced Mode)
The enhanced PWM mode generates a Pulse-Width
Modulation (PWM) signal on up to four different output
pins with up to 10 bits of resolution. The period, duty
cycle, and resolution are controlled by the following
registers:
• PR2 registers
• T2CON registers
• CCPR1L registers
• CCP1CON registers
The ECCP modules have the following additional PWM
registers which control Auto-shutdown, Auto-restart,
Dead-band Delay and PWM Steering modes:
• CCP1AS registers
• PSTR1CON registers
• PWM1CON registers
The enhanced PWM module can generate the following
four PWM Output modes:
• Single PWM
• Half-Bridge PWM
• Full-Bridge PWM (PIC16F/LF1823 only)
• Single PWM with PWM Steering Mode
To select an Enhanced PWM Output mode, the P1M bits
of the CCP1CON register must be configured
appropriately.
The PWM outputs are multiplexed with I/O pins and are
designated P1A, P1B, P1C and P1D. The polarity of the
PWM pins is configurable and is selected by setting the
bits CCP1M<3:0> in the CCP1CON register
appropriately.
Figure 23-5 shows an example of a simplified block
diagram of the Enhanced PWM module.
Table 23-8 shows the pin assignments for various
Enhanced PWM modes.
FIGURE 23-5: EXAMPLE SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODE
Note 1: The corresponding TRIS bit must be
cleared to enable the PWM output on the
CCP1 pin.
2: Clearing the CCP1CON register will
relinquish control of the CCP1 pin.
3: Any pin not used in the enhanced PWM
mode is available for alternate pin
functions, if applicable.
4: To prevent the generation of an
incomplete waveform when the PWM is
first enabled, the ECCP module waits
until the start of a new PWM period before
generating a PWM signal.
CCPR1L
CCPR1H (Slave)
Comparator
TMR2
Comparator
PR2
(1)
RQ
S
Duty Cycle Registers DC1B<1:0>
Clear Timer,
toggle PWM pin and
latch duty cycle
Note 1: The 8-bit timer TMR1 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit time
base.
2: PIC16F/LF1823 only.
TRISx
CCP1/P1A
TRISx
P1B
TRISx
P1C(2)
TRISx
P1D(2)
Output
Controller
P1M<1:0>
2
CCP1M<3:0>
4
PWM1CON
CCP1/P1A
P1B
P1C(2)
P1D(2)
2010 Microchip Technology Inc. Preliminary DS41413A-page 209
PIC12F/LF1822/16F/LF1823
TABLE 23-8: EXAMPLE PIN ASSIGNMENTS FOR VARIOUS PWM ENHANCED MODES
FIGURE 23-6: EXAMPLE PWM (ENHANCED MODE) OUTPUT RELATIONSHIPS (ACTIVE-HIGH
STATE)
ECCP Mode P1M<1:0> CCP1/P1A P1B P1C(2) P1D(2)
Single 00 Yes(1) Yes(1) Yes(1) Yes(1)
Half-Bridge 10 Yes Yes No No
Full-Bridge, Forward(2) 01 Yes Yes Yes Yes
Full-Bridge, Reverse(2) 11 Yes Yes Yes Yes
Note 1: PWM Steering enables outputs in Single mode.
2: PIC16F/LF1823 only.
0
Period
00
10
01
11
Signal PRX+1
PxM<1:0>
PxA Modulated
PxA Modulated
PxB Modulated
PxA Active
PxB Inactive
PxC Inactive
PxD Modulated
PxA Inactive
PxB Modulated
PxC Active
PxD Inactive
Pulse
Width
(Single Output)
(Half-Bridge)
(Full-Bridge,
Forward)
(Full-Bridge,
Reverse)
Delay Delay
Relationships:
• Period = 4 * TOSC * (PRx + 1) * (TMRx Prescale Value)
• Pulse Width = TOSC * (CCPRxL<7:0>:CCPxCON<5:4>) * (TMRx Prescale Value)
• Delay = 4 * TOSC * (PWMxCON<6:0>)
PIC12F/LF1822/16F/LF1823
DS41413A-page 210 Preliminary 2010 Microchip Technology Inc.
FIGURE 23-7: EXAMPLE ENHANCED PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
0
Period
00
10
01
11
Signal PRx+1
PxM<1:0>
PxA Modulated
PxA Modulated
PxB Modulated
PxA Active
PxB Inactive
PxC Inactive
PxD Modulated
PxA Inactive
PxB Modulated
PxC Active
PxD Inactive
Pulse
Width
(Single Output)
(Half-Bridge)
(Full-Bridge,
Forward)
(Full-Bridge,
Reverse)
Delay Delay
Relationships:
• Period = 4 * TOSC * (PRx + 1) * (TMRx Prescale Value)
• Pulse Width = TOSC * (CCPRxL<7:0>:CCPxCON<5:4>) * (TMRx Prescale Value)
• Delay = 4 * TOSC * (PWMxCON<6:0>)
2010 Microchip Technology Inc. Preliminary DS41413A-page 211
PIC12F/LF1822/16F/LF1823
23.4.1 HALF-BRIDGE MODE
In Half-Bridge mode, two pins are used as outputs to
drive push-pull loads. The PWM output signal is output
on the CCP1/P1A pin, while the complementary PWM
output signal is output on the P1B pin (see Figure 23-9).
This mode can be used for Half-Bridge applications, as
shown in Figure 23-9, or for Full-Bridge applications,
where four power switches are being modulated with
two PWM signals.
In Half-Bridge mode, the programmable dead-band delay
can be used to prevent shoot-through current in Half-
Bridge power devices. The value of the PDC<6:0> bits of
the PWM1CON register sets the number of instruction
cycles before the output is driven active. If the value is
greater than the duty cycle, the corresponding output
remains inactive during the entire cycle. See
Section 23.4.5 “Programmable Dead-Band Delay
Mode” for more details of the dead-band delay
operations.
Since the P1A and P1B outputs are multiplexed with
the PORT data latches, the associated TRIS bits must
be cleared to configure P1A and P1B as outputs.
FIGURE 23-8: EXAMPLE OF HALF-
BRIDGE PWM OUTPUT
FIGURE 23-9: EXAMPLE OF HALF-BRIDGE APPLICATIONS
Period
Pulse Width
td
td
(1)
P1A(2)
P1B(2)
td = Dead-Band Delay
Period
(1) (1)
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
P1A
P1B
FET
Driver
FET
Driver
Load
+
-
+
-
FET
Driver
FET
Driver
V+
Load
FET
Driver
FET
Driver
P1A
P1B
Standard Half-Bridge Circuit (“Push-Pull”)
Half-Bridge Output Driving a Full-Bridge Circuit
PIC12F/LF1822/16F/LF1823
DS41413A-page 212 Preliminary 2010 Microchip Technology Inc.
23.4.2 FULL-BRIDGE MODE
(PIC16F/LF1823 ONLY)
In Full-Bridge mode, all four pins are used as outputs.
An example of Full-Bridge application is shown in
Figure 23-10.
In the Forward mode, pin CCP1/P1A is driven to its
active state, pin P1D is modulated, while P1B and P1C
will be driven to their inactive state as shown in
Figure 23-11.
In the Reverse mode, P1C is driven to its active state,
pin P1B is modulated, while P1A and P1D will be driven
to their inactive state as shown Figure 23-11.
P1A, P1B, P1C and P1D outputs are multiplexed with
the PORT data latches. The associated TRIS bits must
be cleared to configure the P1A, P1B, P1C and P1D
pins as outputs.
FIGURE 23-10: EXAMPLE OF FULL-BRIDGE APPLICATION
P1A
P1C
FET
Driver
FET
Driver
V+
V-
Load
FET
Driver
FET
Driver
P1B
P1D
QA
QB QD
QC
2010 Microchip Technology Inc. Preliminary DS41413A-page 213
PIC12F/LF1822/16F/LF1823
FIGURE 23-11: EXAMPLE OF FULL-BRIDGE PWM OUTPUT
Period
Pulse Width
P1A(2)
P1B(2)
P1C(2)
P1D(2)
Forward Mode
(1)
Period
Pulse Width
P1A(2)
P1C(2)
P1D(2)
P1B(2)
Reverse Mode
(1)
(1)
(1)
Note 1: At this time, the TMR2 register is equal to the PR2 register.
2: Output signal is shown as active-high.
PIC12F/LF1822/16F/LF1823
DS41413A-page 214 Preliminary 2010 Microchip Technology Inc.
23.4.2.1 Direction Change in Full-Bridge
Mode
In the Full-Bridge mode, the P1M1 bit in the CCP1CON
register allows users to control the forward/reverse
direction. When the application firmware changes this
direction control bit, the module will change to the new
direction on the next PWM cycle.
A direction change is initiated in software by changing
the P1M1 bit of the CCP1CON register. The following
sequence occurs four Timer cycles prior to the end of
the current PWM period:
• The modulated outputs (P1B and P1D) are placed
in their inactive state.
• The associated unmodulated outputs (P1A and
P1C) are switched to drive in the opposite
direction.
• PWM modulation resumes at the beginning of the
next period.
See Figure 23-12 for an illustration of this sequence.
The Full-Bridge mode does not provide dead-band
delay. As one output is modulated at a time, dead-band
delay is generally not required. There is a situation
where dead-band delay is required. This situation
occurs when both of the following conditions are true:
1. The direction of the PWM output changes when
the duty cycle of the output is at or near 100%.
2. The turn-off time of the power switch, including
the power device and driver circuit, is greater
than the turn-on time.
Figure 23-13 shows an example of the PWM direction
changing from forward to reverse, at a near 100% duty
cycle. In this example, at time t1, the output P1A and
P1D become inactive, while output P1C becomes
active. Since the turn off time of the power devices is
longer than the turn on time, a shoot-through current
will flow through power devices QC and QD (see
Figure 23-10) for the duration of ‘t’. The same
phenomenon will occur to power devices QA and QB
for PWM direction change from reverse to forward.
If changing PWM direction at high duty cycle is required
for an application, two possible solutions for eliminating
the shoot-through current are:
1. Reduce PWM duty cycle for one PWM period
before changing directions.
2. Use switch drivers that can drive the switches off
faster than they can drive them on.
Other options to prevent shoot-through current may
exist.
FIGURE 23-12: EXAMPLE OF PWM DIRECTION CHANGE
Pulse Width
Period(1)
Signal
Note 1: The direction bit P1M1 of the CCP1CON register is written any time during the PWM cycle.
2: When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle. The
modulated P1B and P1D signals are inactive at this time. The length of this time is four Timer counts.
Period
(2)
P1A (Active-High)
P1B (Active-High)
P1C (Active-High)
P1D (Active-High)
Pulse Width
2010 Microchip Technology Inc. Preliminary DS41413A-page 215
PIC12F/LF1822/16F/LF1823
FIGURE 23-13: EXAMPLE OF PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
23.4.3 ENHANCED PWM AUTO-
SHUTDOWN MODE
The PWM mode supports an Auto-Shutdown mode that
will disable the PWM outputs when an external
shutdown event occurs. Auto-Shutdown mode places
the PWM output pins into a predetermined state. This
mode is used to help prevent the PWM from damaging
the application.
The auto-shutdown sources are selected using the
CCP1AS<2:0> bits of the CCP1AS register. A shutdown
event may be generated by:
•A logic ‘0’ on the INT pin
• Comparator C1
• Setting the CCP1ASE bit in firmware
A shutdown condition is indicated by the CCP1ASE
(Auto-Shutdown Event Status) bit of the CCP1AS
register. If the bit is a ‘0’, the PWM pins are operating
normally. If the bit is a ‘1’, the PWM outputs are in the
shutdown state.
When a shutdown event occurs, two things happen:
The CCP1ASE bit is set to ‘1’. The CCP1ASE will
remain set until cleared in firmware or an auto-restart
occurs (see Section 23.4.4 “Auto-Restart Mode”).
The enabled PWM pins are asynchronously placed in
their shutdown states. The PWM output pins are
grouped into pairs [P1A/P1C] and [P1B/P1D]. The state
of each pin pair is determined by the PSS1AC and
PSS1BD bits of the CCP1AS register. Each pin pair may
be placed into one of three states:
• Drive logic ‘1’
• Drive logic ‘0’
• Tri-state (high-impedance)
Forward Period Reverse Period
P1A
TON
TOFF
T = TOFF – TON
P1B
P1C
P1D
External Switch D
Potential
Shoot-Through Current
Note 1: All signals are shown as active-high.
2: TON is the turn-on delay of power switch QC and its driver.
3: TOFF is the turn-off delay of power switch QD and its driver.
External Switch C
t1
PW
PW
Note 1: The auto-shutdown condition is a level-
based signal, not an edge-based signal.
As long as the level is present, the auto-
shutdown will persist.
2: Writing to the CCP1ASE bit is disabled
while an auto-shutdown condition
persists.
3: Once the auto-shutdown condition has
been removed and the PWM restarted
(either through firmware or auto-restart)
the PWM signal will always restart at the
beginning of the next PWM period.
PIC12F/LF1822/16F/LF1823
DS41413A-page 216 Preliminary 2010 Microchip Technology Inc.
FIGURE 23-14: PWM AUTO-SHUTDOWN WITH FIRMWARE RESTART (P1RSEN = 0)
23.4.4 AUTO-RESTART MODE
The Enhanced PWM can be configured to automati-
cally restart the PWM signal once the auto-shutdown
condition has been removed. Auto-restart is enabled by
setting the P1RSEN bit in the PWM1CON register.
If auto-restart is enabled, the CCP1ASE bit will remain
set as long as the auto-shutdown condition is active.
When the auto-shutdown condition is removed, the
CCP1ASE bit will be cleared via hardware and normal
operation will resume.
FIGURE 23-15: PWM AUTO-SHUTDOWN WITH AUTO-RESTART (P1RSEN = 1)
Shutdown
PWM
CCP1ASE bit
Activity
Event
Shutdown
Event Occurs Shutdown
Event Clears
PWM
Resumes
PWM Period
Start of
PWM Period
CCP1ASE
Cleared by
Firmware
Timer
Overflow Timer
Overflow
Timer
Overflow Timer
Overflow
Missing Pulse
(Auto-Shutdown) Missing Pulse
(CCP1ASE not clear)
Timer
Overflow
Shutdown
PWM
CCP1ASE bit
Activity
Event
Shutdown
Event Occurs
Shutdown
Event Clears
PWM Period
Start of
PWM Period
CCP1ASE
Cleared by
Hardware
Timer
Overflow Timer
Overflow
Timer
Overflow Timer
Overflow
Missing Pulse
(Auto-Shutdown) Missing Pulse
(CCP1ASE not clear)
Timer
Overflow
PWM
Resumes
2010 Microchip Technology Inc. Preliminary DS41413A-page 217
PIC12F/LF1822/16F/LF1823
23.4.5 PROGRAMMABLE DEAD-BAND
DELAY MODE
In Half-Bridge applications where all power switches
are modulated at the PWM frequency, the power
switches normally require more time to turn off than to
turn on. If both the upper and lower power switches are
switched at the same time (one turned on, and the
other turned off), both switches may be on for a short
period of time until one switch completely turns off.
During this brief interval, a very high current (shoot-
through current) will flow through both power switches,
shorting the bridge supply. To avoid this potentially
destructive shoot-through current from flowing during
switching, turning on either of the power switches is
normally delayed to allow the other switch to
completely turn off.
In Half-Bridge mode, a digitally programmable dead-
band delay is available to avoid shoot-through current
from destroying the bridge power switches. The delay
occurs at the signal transition from the non-active state
to the active state. See Figure 23-16 for illustration.
The lower seven bits of the associated PWM1CON
register (Register 23-3) sets the delay period in terms
of microcontroller instruction cycles (TCY or 4 TOSC).
FIGURE 23-16: EXAMPLE OF HALF-
BRIDGE PWM OUTPUT
FIGURE 23-17: EXAMPLE OF HALF-BRIDGE APPLICATIONS
Period
Pulse Width
td
td
(1)
P1A(2)
P1B(2)
td = Dead-Band Delay
Period
(1) (1)
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
P1A
P1B
FET
Driver
FET
Driver
V+
V-
Load
+
V
-
+
V
-
Standard Half-Bridge Circuit (“Push-Pull”)
PIC12F/LF1822/16F/LF1823
DS41413A-page 218 Preliminary 2010 Microchip Technology Inc.
23.4.6 PWM STEERING MODE
In Single Output mode, PWM steering allows any of the
PWM pins to be the modulated signal. Additionally, the
same PWM signal can be simultaneously available on
multiple pins.
Once the Single Output mode is selected
(CCP1M<3:2> = 11 and P1M<1:0> = 00 of the
CCP1CON register), the user firmware can bring out
the same PWM signal to one, two, three or four output
pins by setting the appropriate STR1 bits of the
PSTR1CON register, as shown in Table 23-8.
While the PWM Steering mode is active, the
CCP1M<1:0> bits of the CCP1CON register determine
the polarity of the output pins.
The PWM auto-shutdown operation also applies to
PWM Steering mode as described in Section 23.4.3
“Enhanced PWM Auto-shutdown mode”. An auto-
shutdown event will only affect pins that have PWM
outputs enabled.
FIGURE 23-18: SIMPLIFIED STEERING
BLOCK DIAGRAM
Note: The associated TRIS bits must be set to
output (‘0’) to enable the pin output driver
in order to see the PWM signal on the pin.
1
0TRIS
P1A pin
PORT Data
P1A Signal
STR1A
1
0
TRIS
P1B pin
PORT Data
STR1B
1
0
TRIS
P1C pin(3)
PORT Data
STR1C
1
0
TRIS
P1D pin(3)
PORT Data
STR1D
Note 1: Port outputs are configured as shown when
the CCP1CON register bits P1M<1:0> = 00
and CCP1M<3:2> = 11.
2: Single PWM output requires setting at least
one of the STR1 bits.
3: PIC16F/LF1823 only.
CCP1M1
CCP1M0
CCP1M1
CCP1M0
2010 Microchip Technology Inc. Preliminary DS41413A-page 219
PIC12F/LF1822/16F/LF1823
23.4.6.1 Steering Synchronization
The STR1SYNC bit of the PSTR1CON register gives
the user two selections of when the steering event will
happen. When the STR1SYNC bit is ‘0’, the steering
event will happen at the end of the instruction that
writes to the PSTR1CON register. In this case, the
output signal at the output pins may be an incomplete
PWM waveform. This operation is useful when the user
firmware needs to immediately remove a PWM signal
from the pin.
When the STR1SYNC bit is ‘1’, the effective steering
update will happen at the beginning of the next PWM
period. In this case, steering on/off the PWM output will
always produce a complete PWM waveform.
Figures 23-19 and 23-20 illustrate the timing diagrams
of the PWM steering depending on the STR1SYNC
setting.
23.4.7 START-UP CONSIDERATIONS
When any PWM mode is used, the application
hardware must use the proper external pull-up and/or
pull-down resistors on the PWM output pins.
The CCP1M<1:0> bits of the CCP1CON register allow
the user to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output
pins (P1A/P1C and P1B/P1D). The PWM output
polarities must be selected before the PWM pin output
drivers are enabled. Changing the polarity
configuration while the PWM pin output drivers are
enable is not recommended since it may result in
damage to the application circuits.
The P1A, P1B, P1C and P1D output latches may not be
in the proper states when the PWM module is
initialized. Enabling the PWM pin output drivers at the
same time as the Enhanced PWM modes may cause
damage to the application circuit. The Enhanced PWM
modes must be enabled in the proper Output mode and
complete a full PWM cycle before enabling the PWM
pin output drivers. The completion of a full PWM cycle
is indicated by the TMR2IF bit of the PIR1 register
being set as the second PWM period begins.
FIGURE 23-19: EXAMPLE OF STEERING EVENT AT END OF INSTRUCTION (STR1SYNC = 0)
FIGURE 23-20: EXAMPLE OF STEERING EVENT AT BEGINNING OF INSTRUCTION
(STR1SYNC = 1)
Note: When the microcontroller is released from
Reset, all of the I/O pins are in the high-
impedance state. The external circuits
must keep the power switch devices in the
Off state until the microcontroller drives
the I/O pins with the proper signal levels or
activates the PWM output(s).
PWM
P1n = PWM
STR1
P1<D:A> PORT Data
PWM Period
PORT Data
PWM
PORT Data
P1n = PWM
STR1
P1<D:A> PORT Data
PIC12F/LF1822/16F/LF1823
DS41413A-page 220 Preliminary 2010 Microchip Technology Inc.
TABLE 23-9: SUMMARY OF REGISTERS ASSOCIATED WITH ENHANCED PWM
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
CCP1CON P1M<1:0> DC1B<1:0> CCP1M<3:0> 221
CCP1AS CCP1ASE CCP1AS<2:0> PSS1AC<1:0> PSS1BD<1:0> 222
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
PR2 Timer2 Period Register 184*
PSTR1CON — — — STR1SYNC STR1D(1) STR1C(1) STR1B STR1A 224
PWM1CON P1RSEN P1DC<6:0> 223
T2CON — T2OUTPS<3:0> TMR2ON T2CKPS<:0>1 186
TMR2 Timer2 Module Register 184
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) —— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = Unimplemented location, read as ‘0’. Shaded cells are not used by the PWM.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 221
PIC12F/LF1822/16F/LF1823
REGISTER 23-1: CCP1CON: CCP1 CONTROL REGISTER
R/W-00 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
P1M<1:0>(1) DC1B<1:0> CCP1M<3:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Reset
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-6 P1M<1:0>: Enhanced PWM Output Configuration bits(1)
Capture mode:
Unused
Compare mode:
Unused
PWM mode:
If CCP1M<3:2> = 00, 01, 10:
xx = P1A assigned as Capture/Compare input; P1B, P1C, P1D assigned as port pins(1)
If CCP1M<3:2> = 11:
00 = Single output; P1A modulated; P1B, P1C, P1D assigned as port pins
01 = Full-Bridge output forward; P1D modulated; P1A active; P1B, P1C inactive(1)
10 = Half-Bridge output; P1A, P1B modulated with dead-band control; P1C, P1D assigned as port pins
11 = Full-Bridge output reverse; P1B modulated; P1C active; P1A, P1D inactive(1)
bit 5-4 DC1B<1:0>: PWM Duty Cycle Least Significant bits
Capture mode:
Unused
Compare mode:
Unused
PWM mode:
These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L.
bit 3-0 CCP1M<3:0>: ECCP1 Mode Select bits
0000 = Capture/Compare/PWM off (resets ECCP1 module)
0001 = Reserved
0010 = Compare mode: toggle output on match
0011 = Reserved
0100 = Capture mode: every falling edge
0101 = Capture mode: every rising edge
0110 = Capture mode: every 4th rising edge
0111 = Capture mode: every 16th rising edge
1000 = Compare mode: initialize ECCP1 pin low; set output on compare match (set CCP1IF)
1001 = Compare mode: initialize ECCP1 pin high; clear output on compare match (set CCP1IF)
1010 = Compare mode: generate software interrupt only; ECCP1 pin reverts to I/O state
1011 = Compare mode: Special Event Trigger (CCP1 resets TMR1, sets CCP1IF bit, and starts A/D conversion
if A/D module is enabled)
PWM mode:
1100 = PWM mode: P1A, P1C active-high; P1B, P1D active-high
1101 = PWM mode: P1A, P1C active-high; P1B, P1D active-low
1110 = PWM mode: P1A, P1C active-low; P1B, P1D active-high
1111 = PWM mode: P1A, P1C active-low; P1B, P1D active-low
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 222 Preliminary 2010 Microchip Technology Inc.
REGISTER 23-2: CCP1AS: CCP1 AUTO-SHUTDOWN CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
CCP1ASE CCP1AS<2:0> PSS1AC<1:0> PSS1BD<1:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 CCP1ASE: CCP1 Auto-Shutdown Event Status bit
1 = A shutdown event has occurred; CCP1 outputs are in shutdown state
0 = CCP1 outputs are operating
bit 6-4 CC1PAS<2:0>: CCP1 Auto-Shutdown Source Select bits
000 = Auto-shutdown is disabled
001 = Comparator C1 output low(1)
010 = Comparator C2 output low(1, 2)
011 = Either Comparator C1 or C2 low(1, 2)
100 =VIL on INT pin
101 =V
IL on INT pin or Comparator C1 low(1)
110 =VIL on INT pin or Comparator C2 low(1, 2)
111 =VIL on INT pin or Comparator C1 or Comparator C2 low(1, 2)
bit 3-2 PSS1AC<1:0>: Pins P1A and P1C Shutdown State Control bits(2)
00 = Drive pins P1A and P1C to ‘0’ (2)
01 = Drive pins P1A and P1C to ‘1’ (2)
1x = Pins P1A and P1C tri-state(2)
bit 1-0 PSS1BD<1:0>: Pins P1B and P1D Shutdown State Control bits(2)
00 = Drive pins P1B and P1D to ‘0’
01 = Drive pins P1B and P1D to ‘1’
1x = Pins P1B and P1D tri-state
Note 1: If C1SYNC is enabled, the shutdown will be delayed by Timer1.
2: C2, P1C and P1D available on PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 223
PIC12F/LF1822/16F/LF1823
REGISTER 23-3: PWM1CON: ENHANCED PWM CONTROL REGISTER
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
P1RSEN P1DC<6:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 P1RSEN: PWM Restart Enable bit
1 = Upon auto-shutdown, the CCP1ASE bit clears automatically once the shutdown event goes
away; the PWM restarts automatically
0 = Upon auto-shutdown, CCP1ASE must be cleared in software to restart the PWM
bit 6-0 P1DC<6:0>: PWM Delay Count bits
P1DC1 = Number of FOSC/4 (4 * TOSC) cycles between the scheduled time when a PWM signal
should transition active and the actual time it transitions active
Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe
mode is enabled.
PIC12F/LF1822/16F/LF1823
DS41413A-page 224 Preliminary 2010 Microchip Technology Inc.
REGISTER 23-4: PSTR1CON: PWM STEERING CONTROL REGISTER(1)
U-0 U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-1/1
— — — STR1SYNC STR1D STR1C STR1B STR1A
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-5 Unimplemented: Read as ‘0’
bit 4 STR1SYNC: Steering Sync bit
1 = Output steering update occurs on next PWM period
0 = Output steering update occurs at the beginning of the instruction cycle boundary
bit 3 STR1D: Steering Enable bit D(2)
1 = P1D pin has the PWM waveform with polarity control from CCP1M<1:0>
0 = P1D pin is assigned to port pin
bit 2 STR1C: Steering Enable bit C(2)
1 = P1C pin has the PWM waveform with polarity control from CCP1M<1:0>
0 = P1C pin is assigned to port pin
bit 1 STR1B: Steering Enable bit B
1 = P1B pin has the PWM waveform with polarity control from CCP1M<1:0>
0 = P1B pin is assigned to port pin
bit 0 STR1A: Steering Enable bit A
1 = P1A pin has the PWM waveform with polarity control from CCP1M<1:0>
0 = P1A pin is assigned to port pin
Note 1: The PWM Steering mode is available only when the CCP1CON register bits CCP1M<3:2> = 11 and
P1M<1:0> = 00.
2: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 225
PIC12F/LF1822/16F/LF1823
24.0 MASTER SYNCHRONOUS
SERIAL PORT MODULE
24.1 Master SSP (MSSP1) Module
Overview
The Master Synchronous Serial Port (MSSP1) module
is a serial interface useful for communicating with other
peripheral or microcontroller devices. These peripheral
devices may be Serial EEPROMs, shift registers, dis-
play drivers, A/D converters, etc. The MSSP1 module
can operate in one of two modes:
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit (I2C™)
The SPI interface supports the following modes and
features:
•Master mode
• Slave mode
• Clock Parity
• Slave Select Synchronization (Slave mode only)
• Daisy chain connection of slave devices
Figure 24-1 is a block diagram of the SPI interface
module.
FIGURE 24-1: MSSP1 BLOCK DIAGRAM (SPI MODE)
( )
Read Write
Data Bus
SSP1SR Reg
SSP1M<3:0>
bit 0 Shift
Clock
SS Control
Enable
Edge
Select
Clock Select
TMR2 Output
TOSC
Prescaler
4, 16, 64
2
Edge
Select
2 (CKP, CKE)
4
TRIS bit
SDO
SSP1BUF Reg
SDI
SS
SCK
Baud rate
generator
(SSP1ADD)
PIC12F/LF1822/16F/LF1823
DS41413A-page 226 Preliminary 2010 Microchip Technology Inc.
The I2C interface supports the following modes and
features:
•Master mode
• Slave mode
• Byte NACKing (Slave mode)
• Limited Multi-master support
• 7-bit and 10-bit addressing
• Start and Stop interrupts
• Interrupt masking
• Clock stretching
• Bus collision detection
• General call address matching
•Address masking
• Address Hold and Data Hold modes
• Selectable SDA hold times
Figure 24-2 is a block diagram of the I2C interface mod-
ule in Master mode. Figure 24-3 is a diagram of the I2C
interface module in Slave mode.
FIGURE 24-2: MSSP1 BLOCK DIAGRAM (I2C™ MASTER MODE)
Read Write
SSP1SR
Start bit, Stop bit,
Start bit detect,
SSP1BUF
Internal
data bus
Set/Reset: S, P, SSP1STAT, WCOL, SSP1OV
Shift
Clock
MSb LSb
SDA
Acknowledge
Generate (SSP1CON2)
Stop bit detect
Write collision detect
Clock arbitration
State counter for
end of XMIT/RCV
SCL
SCL in
Bus Collision
SDA in
Receive Enable (RCEN)
Clock Cntl
Clock arbitrate/BCOL detect
(Hold off clock source)
[SSP1M 3:0]
Baud rate
Reset SEN, PEN (SSP1CON2)
generator
(SSP1ADD)
Address Match detect
Set SSP1IF, BCL1IF
2010 Microchip Technology Inc. Preliminary DS41413A-page 227
PIC12F/LF1822/16F/LF1823
FIGURE 24-3: MSSP1 BLOCK DIAGRAM (I2C™ SLAVE MODE)
Read Write
SSP1SR Reg
Match Detect
SSP1ADD Reg
Start and
Stop bit Detect
SSP1BUF Reg
Internal
Data Bus
Addr Match
Set, Reset
S, P bits
(SSP1STAT Reg)
SCL
SDA
Shift
Clock
MSb LSb
SSP1MSK Reg
PIC12F/LF1822/16F/LF1823
DS41413A-page 228 Preliminary 2010 Microchip Technology Inc.
24.2 SPI Mode Overview
The Serial Peripheral Interface (SPI) bus is a
synchronous serial data communication bus that
operates in Full Duplex mode. Devices communicate in
a master/slave environment where the master device
initiates the communication. A slave device is
controlled through a chip select known as Slave Select.
The SPI bus specifies four signal connections:
• Serial Clock (SCK)
• Serial Data Out (SDO)
• Serial Data In (SDI)
• Slave Select (SS)
Figure 24-1 shows the block diagram of the MSSP1
module when operating in SPI Mode.
The SPI bus operates with a single master device and
one or more slave devices. When multiple slave
devices are used, an independent Slave Select con-
nection is required from the master device to each
slave device.
Figure 24-4 shows a typical connection between a
master device and multiple slave devices.
The master selects only one slave at a time. Most slave
devices have tri-state outputs so their output signal
appears disconnected from the bus when they are not
selected.
Transmissions involve two shift registers, eight bits in
size, one in the master and one in the slave. With either
the master or the slave device, data is always shifted
out one bit at a time, with the Most Significant bit (MSb)
shifted out first. At the same time, a new Least
Significant bit (LSb) is shifted into the same register.
Figure 24-5 shows a typical connection between two
processors configured as master and slave devices.
Data is shifted out of both shift registers on the pro-
grammed clock edge and latched on the opposite edge
of the clock.
The master device transmits information out on its SDO
output pin which is connected to, and received by, the
slave’s SDI input pin. The slave device transmits infor-
mation out on its SDO output pin, which is connected
to, and received by, the master’s SDI input pin.
To begin communication, the master device first sends
out the clock signal. Both the master and the slave
devices should be configured for the same clock polar-
ity.
The master device starts a transmission by sending out
the MSb from its shift register. The slave device reads
this bit from that same line and saves it into the LSb
position of its shift register.
During each SPI clock cycle, a full duplex data
transmission occurs. This means that while the master
device is sending out the MSb from its shift register (on
its SDO pin) and the slave device is reading this bit and
saving it as the LSb of its shift register, that the slave
device is also sending out the MSb from its shift register
(on its SDO pin) and the master device is reading this
bit and saving it as the LSb of its shift register.
After 8 bits have been shifted out, the master and slave
have exchanged register values.
If there is more data to exchange, the shift registers are
loaded with new data and the process repeats itself.
Whether the data is meaningful or not (dummy data),
depends on the application software. This leads to
three scenarios for data transmission:
• Master sends useful data and slave sends dummy
data.
• Master sends useful data and slave sends useful
data.
• Master sends dummy data and slave sends useful
data.
Transmissions may involve any number of clock
cycles. When there is no more data to be transmitted,
the master stops sending the clock signal and it dese-
lects the slave.
Every slave device connected to the bus that has not
been selected through its slave select line must disre-
gard the clock and transmission signals and must not
transmit out any data of its own.
2010 Microchip Technology Inc. Preliminary DS41413A-page 229
PIC12F/LF1822/16F/LF1823
FIGURE 24-4: SPI MASTER AND MULTIPLE SLAVE CONNECTION
24.2.1 SPI MODE REGISTERS
The MSSP1 module has five registers for SPI mode
operation. These are:
• MSSP1 STATUS register (SSP1STAT)
• MSSP1 Control Register 1 (SSP1CON1)
• MSSP1 Control Register 3 (SSP1CON3)
• MSSP1 Data Buffer register (SSP1BUF)
• MSSP1 Address register (SSP1ADD)
• MSSP1 Shift register (SSP1SR)
(Not directly accessible)
SSP1CON1 and SSP1STAT are the control and
STATUS registers in SPI mode operation. The
SSP1CON1 register is readable and writable. The
lower 6 bits of the SSP1STAT are read-only. The upper
two bits of the SSP1STAT are read/write.
In one SPI master mode, SSP1ADD can be loaded
with a value used in the Baud Rate Generator. More
information on the Baud Rate Generator is available in
Section 24.7 “Baud Rate Generator”.
SSP1SR is the shift register used for shifting data in
and out. SSP1BUF provides indirect access to the
SSP1SR register. SSP1BUF is the buffer register to
which data bytes are written, and from which data
bytes are read.
In receive operations, SSP1SR and SSP1BUF
together create a buffered receiver. When SSP1SR
receives a complete byte, it is transferred to SSP1BUF
and the SSP1IF interrupt is set.
During transmission, the SSP1BUF is not buffered. A
write to SSP1BUF will write to both SSP1BUF and
SSP1SR.
SPI Master SCK
SDO
SDI
General I/O
General I/O
General I/O
SCK
SDI
SDO
SS
SPI Slave
#1
SCK
SDI
SDO
SS
SPI Slave
#2
SCK
SDI
SDO
SS
SPI Slave
#3
PIC12F/LF1822/16F/LF1823
DS41413A-page 230 Preliminary 2010 Microchip Technology Inc.
24.2.2 SPI MODE OPERATION
When initializing the SPI, several options need to be
specified. This is done by programming the appropriate
control bits (SSP1CON1<5:0> and SSP1STAT<7:6>).
These control bits allow the following to be specified:
• Master mode (SCK1 is the clock output)
• Slave mode (SCK1 is the clock input)
• Clock Polarity (Idle state of SCK1)
• Data Input Sample Phase (middle or end of data
output time)
• Clock Edge (output data on rising/falling edge of
SCK1)
• Clock Rate (Master mode only)
• Slave Select mode (Slave mode only)
To enable the serial port, SSP1 Enable bit, SSP1EN of
the SSP1CON1 register must be set. To reset or recon-
figure SPI mode, clear the SSP1EN bit, re-initialize the
SSP1CONx registers and then set the SSP1EN bit.
This configures the SDI, SDO, SCK and SS pins as
serial port pins. For the pins to behave as the serial port
function, some must have their data direction bits (in
the TRIS register) appropriately programmed as
follows:
• SDI must have corresponding TRIS bit set
• SDO must have corresponding TRIS bit cleared
• SCK (Master mode) must have corresponding
TRIS bit cleared
• SCK (Slave mode) must have corresponding
TRIS bit set
•SS
must have corresponding TRIS bit set
Any serial port function that is not desired may be
overridden by programming the corresponding data
direction (TRIS) register to the opposite value.
The MSSP1 consists of a transmit/receive shift register
(SSP1SR) and a buffer register (SSP1BUF). The
SSP1SR shifts the data in and out of the device, MSb
first. The SSP1BUF holds the data that was written to
the SSP1SR until the received data is ready. Once the
8 bits of data have been received, that byte is moved to
the SSP1BUF register. Then, the Buffer Full Detect bit,
BF of the SSP1STAT register, and the interrupt flag bit,
SSP1IF, are set. This double-buffering of the received
data (SSP1BUF) allows the next byte to start reception
before reading the data that was just received. Any
write to the SSP1BUF register during
transmission/reception of data will be ignored and the
write collision detect bit, WCOL, of the SSP1CON1
register, will be set. User software must clear the
WCOL bit to allow the following write(s) to the
SSP1BUF register to complete successfully.
When the application software is expecting to receive
valid data, the SSP1BUF should be read before the
next byte of data to transfer is written to the SSP1BUF.
The Buffer Full bit, BF of the SSP1STAT register,
indicates when SSP1BUF has been loaded with the
received data (transmission is complete). When the
SSP1BUF is read, the BF bit is cleared. This data may
be irrelevant if the SPI is only a transmitter. Generally,
the MSSP1 interrupt is used to determine when the
transmission/reception has completed. If the interrupt
method is not going to be used, then software polling
can be done to ensure that a write collision does not
occur.
The SSP1SR is not directly readable or writable and
can only be accessed by addressing the SSP1BUF
register. Additionally, the SSP1STAT register indicates
the various Status conditions.
2010 Microchip Technology Inc. Preliminary DS41413A-page 231
PIC12F/LF1822/16F/LF1823
FIGURE 24-5: SPI MASTER/SLAVE CONNECTION
Serial Input Buffer
(BUF)
Shift Register
(SSP1SR)
MSb LSb
SDO
SDI
Processor 1
SCK
SPI Master SSP1M<3:0> = 00xx
Serial Input Buffer
(SSP1BUF)
Shift Register
(SSP1SR)
LSb
MSb
SDI
SDO
Processor 2
SCK
SPI Slave SSP1M<3:0> = 010x
Serial Clock
SS
Slave Select
General I/O (optional)
= 1010
PIC12F/LF1822/16F/LF1823
DS41413A-page 232 Preliminary 2010 Microchip Technology Inc.
24.2.3 SPI MASTER MODE
The master can initiate the data transfer at any time
because it controls the SCK line. The master
determines when the slave (Processor 2, Figure 24-5)
is to broadcast data by the software protocol.
In Master mode, the data is transmitted/received as
soon as the SSP1BUF register is written to. If the SPI
is only going to receive, the SDO output could be dis-
abled (programmed as an input). The SSP1SR register
will continue to shift in the signal present on the SDI pin
at the programmed clock rate. As each byte is
received, it will be loaded into the SSP1BUF register as
if a normal received byte (interrupts and Status bits
appropriately set).
The clock polarity is selected by appropriately
programming the CKP bit of the SSP1CON1 register
and the CKE bit of the SSP1STAT register. This then,
would give waveforms for SPI communication as
shown in Figure 24-6, Figure 24-8 and Figure 24-9,
where the MSB is transmitted first. In Master mode, the
SPI clock rate (bit rate) is user programmable to be one
of the following:
•F
OSC/4 (or TCY)
•FOSC/16 (or 4 * TCY)
•FOSC/64 (or 16 * TCY)
• Timer2 output/2
• Fosc/(4 * (SSP1ADD + 1))
Figure 24-6 shows the waveforms for Master mode.
When the CKE bit is set, the SDO data is valid before
there is a clock edge on SCK. The change of the input
sample is shown based on the state of the SMP bit. The
time when the SSP1BUF is loaded with the received
data is shown.
FIGURE 24-6: SPI MODE WAVEFORM (MASTER MODE)
SCK
(CKP = 0
SCK
(CKP = 1
SCK
(CKP = 0
SCK
(CKP = 1
4 Clock
Modes
Input
Sample
Input
Sample
SDI
bit 7 bit 0
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
bit 7
SDI
SSP1IF
(SMP = 1)
(SMP = 0)
(SMP = 1)
CKE = 1)
CKE = 0)
CKE = 1)
CKE = 0)
(SMP = 0)
Write to
SSP1BUF
SSP1SR to
SSP1BUF
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
(CKE = 0)
(CKE = 1)
bit 0
2010 Microchip Technology Inc. Preliminary DS41413A-page 233
PIC12F/LF1822/16F/LF1823
24.2.4 SPI SLAVE MODE
In Slave mode, the data is transmitted and received as
external clock pulses appear on SCK. When the last
bit is latched, the SSP1IF interrupt flag bit is set.
Before enabling the module in SPI Slave mode, the clock
line must match the proper Idle state. The clock line can
be observed by reading the SCK pin. The Idle state is
determined by the CKP bit of the SSP1CON1 register.
While in Slave mode, the external clock is supplied by
the external clock source on the SCK pin. This external
clock must meet the minimum high and low times as
specified in the electrical specifications.
While in Sleep mode, the slave can transmit/receive
data. The shift register is clocked from the SCK pin
input and when a byte is received, the device will gen-
erate an interrupt. If enabled, the device will wake-up
from Sleep.
24.2.4.1 Daisy-Chain Configuration
The SPI bus can sometimes be connected in a
daisy-chain configuration. The first slave output is con-
nected to the second slave input, the second slave
output is connected to the third slave input, and so on.
The final slave output is connected to the master input.
Each slave sends out, during a second group of clock
pulses, an exact copy of what was received during the
first group of clock pulses. The whole chain acts as
one large communication shift register. The
daisy-chain feature only requires a single Slave Select
line from the master device.
Figure 24-7 shows the block diagram of a typical
daisy-chain connection when operating in SPI Mode.
In a daisy-chain configuration, only the most recent
byte on the bus is required by the slave. Setting the
BOEN bit of the SSP1CON3 register will enable writes
to the SSP1BUF register, even if the previous byte has
not been read. This allows the software to ignore data
that may not apply to it.
24.2.5 SLAVE SELECT
SYNCHRONIZATION
The Slave Select can also be used to synchronize com-
munication. The Slave Select line is held high until the
master device is ready to communicate. When the
Slave Select line is pulled low, the slave knows that a
new transmission is starting.
If the slave fails to receive the communication properly,
it will be reset at the end of the transmission, when the
Slave Select line returns to a high state. The slave is
then ready to receive a new transmission when the
Slave Select line is pulled low again. If the Slave Select
line is not used, there is a risk that the slave will even-
tually become out of sync with the master. If the slave
misses a bit, it will always be one bit off in future trans-
missions. Use of the Slave Select line allows the slave
and master to align themselves at the beginning of
each transmission.
The SS pin allows a Synchronous Slave mode. The
SPI must be in Slave mode with SS pin control enabled
(SSP1CON1<3:0> = 0100).
When the SS pin is low, transmission and reception are
enabled and the SDO pin is driven.
When the SS pin goes high, the SDO pin is no longer
driven, even if in the middle of a transmitted byte and
becomes a floating output. External pull-up/pull-down
resistors may be desirable depending on the applica-
tion.
When the SPI module resets, the bit counter is forced
to ‘0’. This can be done by either forcing the SS pin to
a high level or clearing the SSP1EN bit.
Note 1: When the SPI is in Slave mode with SS pin
control enabled (SSP1CON1<3:0> =
0100), the SPI module will reset if the SS
pin is set to VDD.
2: When the SPI is used in Slave mode with
CKE set; the user must enable SS pin
control.
3: While operated in SPI Slave mode the
SMP bit of the SSP1STAT register must
remain clear.
PIC12F/LF1822/16F/LF1823
DS41413A-page 234 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-7: SPI DAISY-CHAIN CONNECTION
FIGURE 24-8: SLAVE SELECT SYNCHRONOUS WAVEFORM
SPI Master SCK
SDO
SDI
General I/O
SCK
SDI
SDO
SS
SPI Slave
#1
SCK
SDI
SDO
SS
SPI Slave
#2
SCK
SDI
SDO
SS
SPI Slave
#3
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit 7
SDO bit 7 bit 6 bit 7
SSP1IF
Interrupt
CKE = 0)
CKE = 0)
Write to
SSP1BUF
SSP1SR to
SSP1BUF
SS
Flag
bit 0
bit 7
bit 0
bit 6
SSP1BUF to
SSP1SR
Shift register SSP1SR
and bit count are reset
2010 Microchip Technology Inc. Preliminary DS41413A-page 235
PIC12F/LF1822/16F/LF1823
FIGURE 24-9: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0)
FIGURE 24-10: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1)
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit 7
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SSP1IF
Interrupt
CKE = 0)
CKE = 0)
Write to
SSP1BUF
SSP1SR to
SSP1BUF
SS
Flag
Optional
bit 0
detection active
Write Collision
Valid
SCK
(CKP = 1
SCK
(CKP = 0
Input
Sample
SDI
bit 7 bit 0
SDO bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0
SSP1IF
Interrupt
CKE = 1)
CKE = 1)
Write to
SSP1BUF
SSP1SR to
SSP1BUF
SS
Flag
Not Optional
Write Collision
detection active
Valid
PIC12F/LF1822/16F/LF1823
DS41413A-page 236 Preliminary 2010 Microchip Technology Inc.
24.2.6 SPI OPERATION IN SLEEP MODE
In SPI Master mode, module clocks may be operating
at a different speed than when in full power mode; in
the case of the Sleep mode, all clocks are halted.
Special care must be taken by the user when the
MSSP1 clock is much faster than the system clock.
In Slave mode, when MSSP1 interrupts are enabled,
after the master completes sending data, an MSSP1
interrupt will wake the controller from Sleep.
If an exit from Sleep mode is not desired, MSSP1
interrupts should be disabled.
In SPI Master mode, when the Sleep mode is selected,
all module clocks are halted and the transmis-
sion/reception will remain in that state until the device
wakes. After the device returns to Run mode, the mod-
ule will resume transmitting and receiving data.
In SPI Slave mode, the SPI Transmit/Receive Shift
register operates asynchronously to the device. This
allows the device to be placed in Sleep mode and data
to be shifted into the SPI Transmit/Receive Shift
register. When all 8 bits have been received, the
MSSP1 interrupt flag bit will be set and if enabled, will
wake the device.
TABLE 24-1: SUMMARY OF REGISTERS ASSOCIATED WITH SPI OPERATION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA — — —ANSA4 —ANSA2 ANSA1 ANSA0 122
ANSELC — — — — ANSC3 ANSC2 ANSC1 ANSC0 126
APFCON RXDTSEL SDOSEL SSSEL —T1GSEL TXCKSEL P1BSEL CCP1SEL 118
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
SSP1BUF Synchronous Serial Port Receive Buffer/Transmit Register 229*
SSP1CON1 WCOL SSPOV SSPEN CKP SSPM<3:0> 275
SSP1CON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN 277
SSP1STAT SMP CKE D/A P S R/W UA BF 274
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = Unimplemented location, read as ‘0’. Shaded cells are not used by the MSSP1 in SPI mode.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 237
PIC12F/LF1822/16F/LF1823
24.3 I2C MODE OVERVIEW
The Inter-Integrated Circuit Bus (I²C) is a multi-master
serial data communication bus. Devices communicate
in a master/slave environment where the master
devices initiate the communication. A Slave device is
controlled through addressing.
The I2C bus specifies two signal connections:
• Serial Clock (SCL)
• Serial Data (SDA)
Figure 24-11 shows the block diagram of the MSSP1
module when operating in I2C Mode.
Both the SCL and SDA connections are bidirectional
open-drain lines, each requiring pull-up resistors for the
supply voltage. Pulling the line to ground is considered
a logical zero and letting the line float is considered a
logical one.
Figure 24-11 shows a typical connection between two
processors configured as master and slave devices.
The I2C bus can operate with one or more master
devices and one or more slave devices.
There are four potential modes of operation for a given
device:
• Master Transmit mode
(master is transmitting data to a slave)
• Master Receive mode
(master is receiving data from a slave)
•Slave Transmit mode
(slave is transmitting data to a master)
• Slave Receive mode
(slave is receiving data from the master)
To begin communication, a master device starts out in
Master Transmit mode. The master device sends out a
Start bit followed by the address byte of the slave it
intends to communicate with. This is followed by a sin-
gle Read/Write bit, which determines whether the mas-
ter intends to transmit to or receive data from the slave
device.
If the requested slave exists on the bus, it will respond
with an Acknowledge bit, otherwise known as an ACK.
The master then continues in either Transmit mode or
Receive mode and the slave continues in the comple-
ment, either in Receive mode or Transmit mode,
respectively.
A Start bit is indicated by a high-to-low transition of the
SDA line while the SCL line is held high. Address and
data bytes are sent out, Most Significant bit (MSb) first.
The Read/Write bit is sent out as a logical one when the
master intends to read data from the slave, and is sent
out as a logical zero when it intends to write data to the
slave.
FIGURE 24-11: I2C MASTER/
SLAVE CONNECTION
The Acknowledge bit (ACK) is an active-low signal,
which holds the SDA line low to indicate to the transmit-
ter that the slave device has received the transmitted
data and is ready to receive more.
The transition of a data bit is always performed while
the SCL line is held low. Transitions that occur while the
SCL line is held high are used to indicate Start and Stop
bits.
If the master intends to write to the slave, then it repeat-
edly sends out a byte of data, with the slave responding
after each byte with an ACK bit. In this example, the
master device is in Master Transmit mode and the
slave is in Slave Receive mode.
If the master intends to read from the slave, then it
repeatedly receives a byte of data from the slave, and
responds after each byte with an ACK bit. In this exam-
ple, the master device is in Master Receive mode and
the slave is Slave Transmit mode.
On the last byte of data communicated, the master
device may end the transmission by sending a Stop bit.
If the master device is in Receive mode, it sends the
Stop bit in place of the last ACK bit. A Stop bit is indi-
cated by a low-to-high transition of the SDA line while
the SCL line is held high.
In some cases, the master may want to maintain con-
trol of the bus and re-initiate another transmission. If
so, the master device may send another Start bit in
place of the Stop bit or last ACK bit when it is in receive
mode.
The I2C bus specifies three message protocols;
• Single message where a master writes data to a
slave.
• Single message where a master reads data from
a slave.
• Combined message where a master initiates a
minimum of two writes, or two reads, or a
combination of writes and reads, to one or more
slaves.
Master
SCL
SDA
SCL
SDA
Slave
VDD
VDD
PIC12F/LF1822/16F/LF1823
DS41413A-page 238 Preliminary 2010 Microchip Technology Inc.
When one device is transmitting a logical one, or letting
the line float, and a second device is transmitting a log-
ical zero, or holding the line low, the first device can
detect that the line is not a logical one. This detection,
when used on the SCL line, is called clock stretching.
Clock stretching gives slave devices a mechanism to
control the flow of data. When this detection is used on
the SDA line, it is called arbitration. Arbitration ensures
that there is only one master device communicating at
any single time.
24.3.1 CLOCK STRETCHING
When a slave device has not completed processing
data, it can delay the transfer of more data through the
process of Clock Stretching. An addressed slave
device may hold the SCL clock line low after receiving
or sending a bit, indicating that it is not yet ready to con-
tinue. The master that is communicating with the slave
will attempt to raise the SCL line in order to transfer the
next bit, but will detect that the clock line has not yet
been released. Because the SCL connection is
open-drain, the slave has the ability to hold that line low
until it is ready to continue communicating.
Clock stretching allows receivers that cannot keep up
with a transmitter to control the flow of incoming data.
24.3.2 ARBITRATION
Each master device must monitor the bus for Start and
Stop bits. If the device detects that the bus is busy, it
cannot begin a new message until the bus returns to an
Idle state.
However, two master devices may try to initiate a trans-
mission on or about the same time. When this occurs,
the process of arbitration begins. Each transmitter
checks the level of the SDA data line and compares it
to the level that it expects to find. The first transmitter to
observe that the two levels don’t match, loses arbitra-
tion, and must stop transmitting on the SDA line.
For example, if one transmitter holds the SDA line to a
logical one (lets it float) and a second transmitter holds
it to a logical zero (pulls it low), the result is that the
SDA line will be low. The first transmitter then observes
that the level of the line is different than expected and
concludes that another transmitter is communicating.
The first transmitter to notice this difference is the one
that loses arbitration and must stop driving the SDA
line. If this transmitter is also a master device, it also
must stop driving the SCL line. It then can monitor the
lines for a Stop condition before trying to reissue its
transmission. In the meantime, the other device that
has not noticed any difference between the expected
and actual levels on the SDA line continues with its
original transmission. It can do so without any compli-
cations, because so far, the transmission appears
exactly as expected with no other transmitter disturbing
the message.
Slave Transmit mode can also be arbitrated, when a
master addresses multiple slaves, but this is less com-
mon.
If two master devices are sending a message to two dif-
ferent slave devices at the address stage, the master
sending the lower slave address always wins arbitra-
tion. When two master devices send messages to the
same slave address, and addresses can sometimes
refer to multiple slaves, the arbitration process must
continue into the data stage.
Arbitration usually occurs very rarely, but it is a neces-
sary process for proper multi-master support.
24.4 I2C Mode Operation
All MSSP1 I2C communication is byte oriented and
shifted out MSb first. Six SFR registers and 2 interrupt
flags interface the module with the PIC® microcon-
troller and user software. Two pins, SDA and SCL, are
exercised by the module to communicate with other
external I2C devices.
24.4.1 BYTE FORMAT
All communication in I2C is done in 9-bit segments. A
byte is sent from a Master to a Slave or vice-versa, fol-
lowed by an Acknowledge bit sent back. After the 8th
falling edge of the SCL line, the device outputting data
on the SDA changes that pin to an input and reads in
an acknowledge value on the next clock pulse.
The clock signal, SCL, is provided by the master. Data
is valid to change while the SCL signal is low, and
sampled on the rising edge of the clock. Changes on
the SDA line while the SCL line is high define special
conditions on the bus, explained below.
24.4.2 DEFINITION OF I2C TERMINOLOGY
There is language and terminology in the description
of I2C communication that have definitions specific to
I2C. That word usage is defined below and may be
used in the rest of this document without explana-
tion. This table was adapted from the Phillips I2C™
specification.
24.4.3 SDA AND SCL PINS
Selection of any I2C mode with the SSP1EN bit set,
forces the SCL and SDA pins to be open-drain. These
pins should be set by the user to inputs by setting the
appropriate TRIS bits.
24.4.4 SDA HOLD TIME
The hold time of the SDA pin is selected by the SDAHT
bit of the SSP1CON3 register. Hold time is the time
SDA is held valid after the falling edge of SCL. Setting
the SDAHT bit selects a longer 300 ns minimum hold
time and may help on buses with large capacitance.
Note: Data is tied to output zero when an I2C mode
is enabled.
2010 Microchip Technology Inc. Preliminary DS41413A-page 239
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TABLE 24-2: I2C BUS TERMS 24.4.5 START CONDITION
The I2C specification defines a Start condition as a
transition of SDA from a high to a low state while SCL
line is high. A Start condition is always generated by
the master and signifies the transition of the bus from
an Idle to an Active state. Figure 24-10 shows wave
forms for Start and Stop conditions.
A bus collision can occur on a Start condition if the
module samples the SDA line low before asserting it
low. This does not conform to the I2C Specification that
states no bus collision can occur on a Start.
24.4.6 STOP CONDITION
A Stop condition is a transition of the SDA line from
low-to-high state while the SCL line is high.
24.4.7 RESTART CONDITION
A Restart is valid any time that a Stop would be valid.
A master can issue a Restart if it wishes to hold the
bus after terminating the current transfer. A Restart
has the same effect on the slave that a Start would,
resetting all slave logic and preparing it to clock in an
address. The master may want to address the same or
another slave.
In 10-bit Addressing Slave mode a Restart is required
for the master to clock data out of the addressed
slave. Once a slave has been fully addressed, match-
ing both high and low address bytes, the master can
issue a Restart and the high address byte with the
R/W bit set. The slave logic will then hold the clock
and prepare to clock out data.
After a full match with R/W clear in 10-bit mode, a prior
match flag is set and maintained. Until a Stop condi-
tion, a high address with R/W clear, or high address
match fails.
24.4.8 START/STOP CONDITION INTERRUPT
MASKING
The SCIE and PCIE bits of the SSP1CON3 register
can enable the generation of an interrupt in Slave
modes that do not typically support this function. Slave
modes where interrupt on Start and Stop detect are
already enabled, these bits will have no effect.
TERM Description
Transmitter The device which shifts data out
onto the bus.
Receiver The device which shifts data in
from the bus.
Master The device that initiates a transfer,
generates clock signals and termi-
nates a transfer.
Slave The device addressed by the mas-
ter.
Multi-master A bus with more than one device
that can initiate data transfers.
Arbitration Procedure to ensure that only one
master at a time controls the bus.
Winning arbitration ensures that
the message is not corrupted.
Synchronization Procedure to synchronize the
clocks of two or more devices on
the bus.
Idle No master is controlling the bus,
and both SDA and SCL lines are
high.
Active Any time one or more master
devices are controlling the bus.
Addressed
Slave
Slave device that has received a
matching address and is actively
being clocked by a master.
Matching
Address
Address byte that is clocked into a
slave that matches the value
stored in SSP1ADD.
Write Request Slave receives a matching
address with R/W bit clear, and is
ready to clock in data.
Read Request Master sends an address byte with
the R/W bit set, indicating that it
wishes to clock data out of the
Slave. This data is the next and all
following bytes until a Restart or
Stop.
Clock Stretching When a device on the bus hold
SCL low to stall communication.
Bus Collision Any time the SDA line is sampled
low by the module while it is out-
putting and expected high state.
Note: At least one SCL low time must appear
before a Stop is valid, therefore, if the SDA
line goes low then high again while the SCL
line stays high, only the Start condition is
detected.
PIC12F/LF1822/16F/LF1823
DS41413A-page 240 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-12: I2C START AND STOP CONDITIONS
FIGURE 24-13: I2C RESTART CONDITION
SDA
SCL
P
Stop
Condition
S
Start
Condition
Change of
Data Allowed
Change of
Data Allowed
Restart
Condition
Sr
Change of
Data Allowed
Change of
Data Allowed
2010 Microchip Technology Inc. Preliminary DS41413A-page 241
PIC12F/LF1822/16F/LF1823
24.4.9 ACKNOWLEDGE SEQUENCE
The 9th SCL pulse for any transferred byte in I2C is
dedicated as an Acknowledge. It allows receiving
devices to respond back to the transmitter by pulling
the SDA line low. The transmitter must release control
of the line during this time to shift in the response. The
Acknowledge (ACK) is an active-low signal, pulling the
SDA line low indicated to the transmitter that the
device has received the transmitted data and is ready
to receive more.
The result of an ACK is placed in the ACKSTAT bit of
the SSP1CON2 register.
Slave software, when the AHEN and DHEN bits are
set, allow the user to set the ACK value sent back to
the transmitter. The ACKDT bit of the SSP1CON2 reg-
ister is set/cleared to determine the response.
Slave hardware will generate an ACK response if the
AHEN and DHEN bits of the SSP1CON3 register are
clear.
There are certain conditions where an ACK will not be
sent by the slave. If the BF bit of the SSP1STAT regis-
ter or the SSP1OV bit of the SSP1CON1 register are
set when a byte is received.
When the module is addressed, after the 8th falling
edge of SCL on the bus, the ACKTIM bit of the
SSP1CON3 register is set. The ACKTIM bit indicates
the acknowledge time of the active bus. The ACKTIM
Status bit is only active when the AHEN bit or DHEN
bit is enabled.
24.5 I2C SLAVE MODE OPERATION
The MSSP1 Slave mode operates in one of four
modes selected in the SSP1M bits of SSP1CON1 reg-
ister. The modes can be divided into 7-bit and 10-bit
Addressing mode. 10-bit Addressing modes operate
the same as 7-bit with some additional overhead for
handling the larger addresses.
Modes with Start and Stop bit interrupts operated the
same as the other modes with SSP1IF additionally
getting set upon detection of a Start, Restart, or Stop
condition.
24.5.1 SLAVE MODE ADDRESSES
The SSP1ADD register (Register 24-6) contains the
Slave mode address. The first byte received after a
Start or Restart condition is compared against the
value stored in this register. If the byte matches, the
value is loaded into the SSP1BUF register and an
interrupt is generated. If the value does not match, the
module goes idle and no indication is given to the soft-
ware that anything happened.
The SSP Mask register (Register 24-5) affects the
address matching process. See Section 24.5.9
“SSP1 Mask Register” for more information.
24.5.1.1 I2C Slave 7-bit Addressing Mode
In 7-bit Addressing mode, the LSb of the received data
byte is ignored when determining if there is an address
match.
24.5.1.2 I2C Slave 10-bit Addressing Mode
In 10-bit Addressing mode, the first received byte is
compared to the binary value of ‘1 1 1 1 0 A9 A8
0’. A9 and A8 are the two MSb’s of the 10-bit address
and stored in bits 2 and 1 of the SSP1ADD register.
After the acknowledge of the high byte the UA bit is set
and SCL is held low until the user updates SSP1ADD
with the low address. The low address byte is clocked
in and all 8 bits are compared to the low address value
in SSP1ADD. Even if there is not an address match;
SSP1IF and UA are set, and SCL is held low until
SSP1ADD is updated to receive a high byte again.
When SSP1ADD is updated the UA bit is cleared. This
ensures the module is ready to receive the high
address byte on the next communication.
A high and low address match as a write request is
required at the start of all 10-bit addressing communi-
cation. A transmission can be initiated by issuing a
Restart once the slave is addressed, and clocking in
the high address with the R/W bit set. The slave hard-
ware will then acknowledge the read request and pre-
pare to clock out data. This is only valid for a slave
after it has received a complete high and low address
byte match.
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24.5.2 SLAVE RECEPTION
When the R/W bit of a matching received address byte
is clear, the R/W bit of the SSP1STAT register is
cleared. The received address is loaded into the
SSP1BUF register and acknowledged.
When the overflow condition exists for a received
address, then not Acknowledge is given. An overflow
condition is defined as either bit BF of the SSP1STAT
register is set, or bit SSP1OV of the SSP1CON1 regis-
ter is set. The BOEN bit of the SSP1CON3 register
modifies this operation. For more information see
Register 24-4.
An MSSP1 interrupt is generated for each transferred
data byte. Flag bit, SSP1IF, must be cleared by soft-
ware.
When the SEN bit of the SSP1CON2 register is set,
SCL will be held low (clock stretch) following each
received byte. The clock must be released by setting
the CKP bit of the SSP1CON1 register, except
sometimes in 10-bit mode. See Section 24.2.3 “SPI
Master Mode” for more detail.
24.5.2.1 7-bit Addressing Reception
This section describes a standard sequence of events
for the MSSP1 module configured as an I2C Slave in
7-bit Addressing mode. All decisions made by hard-
ware or software and their effect on reception.
Figure 24-13 and Figure 24-14 is used as a visual
reference for this description.
This is a step by step process of what typically must
be done to accomplish I2C communication.
1. Start bit detected.
2. S bit of SSP1STAT is set; SSP1IF is set if inter-
rupt on Start detect is enabled.
3. Matching address with R/W bit clear is received.
4. The slave pulls SDA low sending an ACK to the
master, and sets SSP1IF bit.
5. Software clears the SSP1IF bit.
6. Software reads received address from
SSP1BUF clearing the BF flag.
7. If SEN = 1; Slave software sets CKP bit to
release the SCL line.
8. The master clocks out a data byte.
9. Slave drives SDA low sending an ACK to the
master, and sets SSP1IF bit.
10. Software clears SSP1IF.
11. Software reads the received byte from
SSP1BUF clearing BF.
12. Steps 8-12 are repeated for all received bytes
from the Master.
13. Master sends Stop condition, setting P bit of
SSP1STAT, and the bus goes idle.
24.5.2.2 7-bit Reception with AHEN and DHEN
Slave device reception with AHEN and DHEN set
operate the same as without these options with extra
interrupts and clock stretching added after the 8th fall-
ing edge of SCL. These additional interrupts allow the
slave software to decide whether it wants to ACK the
receive address or data byte, rather than the hard-
ware. This functionality adds support for PMBus™ that
was not present on previous versions of this module.
This list describes the steps that need to be taken by
slave software to use these options for I2C commun-
cation. Figure 24-15 displays a module using both
address and data holding. Figure 24-16 includes the
operation with the SEN bit of the SSP1CON2 register
set.
1. S bit of SSP1STAT is set; SSP1IF is set if inter-
rupt on Start detect is enabled.
2. Matching address with R/W bit clear is clocked
in. SSP1IF is set and CKP cleared after the 8th
falling edge of SCL.
3. Slave clears the SSP1IF.
4. Slave can look at the ACKTIM bit of the
SSP1CON3 register to determine if the SSP1IF
was after or before the ACK.
5. Slave reads the address value from SSP1BUF,
clearing the BF flag.
6. Slave sets ACK value clocked out to the master
by setting ACKDT.
7. Slave releases the clock by setting CKP.
8. SSP1IF is set after an ACK, not after a NACK.
9. If SEN = 1 the slave hardware will stretch the
clock after the ACK.
10. Slave clears SSP1IF.
11. SSP1IF set and CKP cleared after 8th falling
edge of SCL for a received data byte.
12. Slave looks at ACKTIM bit of SSP1CON3 to
determine the source of the interrupt.
13. Slave reads the received data from SSP1BUF
clearing BF.
14. Steps 7-14 are the same for each received data
byte.
15. Communication is ended by either the slave
sending an ACK =1, or the master sending a
Stop condition. If a Stop is sent and Interrupt on
Stop Detect is disabled, the slave will only know
by polling the P bit of the SSTSTAT register.
Note: SSP1IF is still set after the 9th falling edge of
SCL even if there is no clock stretching and
BF has been cleared. Only if NACK is sent to
Master is SSP1IF not set
2010 Microchip Technology Inc. Preliminary DS41413A-page 243
PIC12F/LF1822/16F/LF1823
FIGURE 24-14: I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 0, DHEN = 0)
Receiving Address
ACK
Receiving Data
ACK
Receiving Data ACK =1
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
SSP1IF
BF
SSP1OV
12345678 12345678 12345678
999
ACK is not sent.
SSP1OV set because
SSP1BUF is still full.
Cleared by software
First byte
of data is
available
in SSP1BUF
SSP1BUF is read
SSP1IF set on 9th
falling edge of
SCL
Cleared by software
P
Bus Master sends
Stop condition
S
From Slave to Master
PIC12F/LF1822/16F/LF1823
DS41413A-page 244 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-15: I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 0, DHEN = 0)
SEN SEN
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0SDA
SCL 123456789 123456789 123456789 P
SSP1IF set on 9th
SCL is not held
CKP is written to ‘1’ in software,
CKP is written to ‘1’ in software,
ACK
low because
falling edge of SCL
releasing SCL
ACK is not sent.
Bus Master sends
CKP
SSP1OV
BF
SSP1IF
SSP1OV set because
SSP1BUF is still full.
Cleared by software
First byte
of data is
available
in SSP1BUF
ACK=1
Cleared by software
SSP1BUF is read
Clock is held low until CKP is set to ‘1’
releasing SCL
Stop condition
S
ACK
ACK
Receive Address Receive Data Receive Data
R/W=0
2010 Microchip Technology Inc. Preliminary DS41413A-page 245
PIC12F/LF1822/16F/LF1823
FIGURE 24-16: I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 1, DHEN = 1)
Receiving Address Receiving Data Received Data
P
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
BF
CKP
S
P
12 3 456 7 8 912345678 9
12345678
Master sends
Stop condition
S
Data is read from SSP1BUF
Cleared by software
SSP1IF is set on
9th falling edge of
SCL, after ACK
CKP set by software,
SCL is released
Slave software
9
ACKTIM cleared by
hardware in 9th
rising edge of SCL
sets ACKDT to
not ACK
When DHEN = 1:
CKP is cleared by
hardware on 8th falling
edge of SCL
Slave software
clears ACKDT to
ACK the received
byte
ACKTIM set by hardware
on 8th falling edge of SCL
When AHEN = 1:
CKP is cleared by hardware
and SCL is stretched
Address is
read from
SSBUF
ACKTIM set by hardware
on 8th falling edge of SCL
ACK
Master Releases SDA
to slave for ACK sequence
No interrupt
after not ACK
from Slave
ACK= 1
ACK
ACKDT
ACKTIM
SSP1IF
If AHEN = 1:
SSP1IF is set
PIC12F/LF1822/16F/LF1823
DS41413A-page 246 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-17: I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 1, DHEN = 1)
Receiving Address Receive Data Receive Data
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
SSP1IF
BF
ACKDT
CKP
S
P
ACK
S12
345678 912
34567 8 9 1234567 8 9
ACK
ACK
Cleared by software
ACKTIM is cleared by hardware
SSP1BUF can be
Set by software,
read any time before
next byte is loaded
release SCL
on 9th rising edge of SCL
Received
address is loaded into
SSP1BUF
Slave software clears
ACKDT to ACK
R/W = 0Master releases
SDA to slave for ACK sequence
the received byte
When AHEN = 1;
on the 8th falling edge
of SCL of an address
byte, CKP is cleared
ACKTIM is set by hardware
on 8th falling edge of SCL
When DHEN = 1;
on the 8th falling edge
of SCL of a received
data byte, CKP is cleared
Received data is
available on SSP1BUF
Slave sends
not ACK
CKP is not cleared
if not ACK
P
Master sends
Stop condition
No interrupt after
if not ACK
from Slave
ACKTIM
2010 Microchip Technology Inc. Preliminary DS41413A-page 247
PIC12F/LF1822/16F/LF1823
24.5.3 SLAVE TRANSMISSION
When the R/W bit of the incoming address byte is set
and an address match occurs, the R/W bit of the
SSP1STAT register is set. The received address is
loaded into the SSP1BUF register, and an ACK pulse
is sent by the slave on the ninth bit.
Following the ACK, slave hardware clears the CKP bit
and the SCL pin is held low (see Section 24.5.6
“Clock Stretching” for more detail). By stretching the
clock, the master will be unable to assert another clock
pulse until the slave is done preparing the transmit
data.
The transmit data must be loaded into the SSP1BUF
register which also loads the SSP1SR register. Then
the SCL pin should be released by setting the CKP bit
of the SSP1CON1 register. The eight data bits are
shifted out on the falling edge of the SCL input. This
ensures that the SDA signal is valid during the SCL
high time.
The ACK pulse from the master-receiver is latched on
the rising edge of the ninth SCL input pulse. This ACK
value is copied to the ACKSTAT bit of the SSP1CON2
register. If ACKSTAT is set (not ACK), then the data
transfer is complete. In this case, when the not ACK is
latched by the slave, the slave goes idle and waits for
another occurrence of the Start bit. If the SDA line was
low (ACK), the next transmit data must be loaded into
the SSP1BUF register. Again, the SCL pin must be
released by setting bit CKP.
An MSSP1 interrupt is generated for each data transfer
byte. The SSP1IF bit must be cleared by software and
the SSP1STAT register is used to determine the status
of the byte. The SSP1IF bit is set on the falling edge of
the ninth clock pulse.
24.5.3.1 Slave Mode Bus Collision
A slave receives a Read request and begins shifting
data out on the SDA line. If a bus collision is detected
and the SBCDE bit of the SSP1CON3 register is set,
the BCL1IF bit of the PIRx register is set. Once a bus
collision is detected, the slave goes Idle and waits to be
addressed again. User software can use the BCL1IF bit
to handle a slave bus collision.
24.5.3.2 7-bit Transmission
A master device can transmit a read request to a
slave, and then clock data out of the slave. The list
below outlines what software for a slave will need to
do to accomplish a standard transmission.
Figure 24-17 can be used as a reference to this list.
1. Master sends a Start condition on SDA and
SCL.
2. S bit of SSP1STAT is set; SSP1IF is set if inter-
rupt-on-Start detect is enabled.
3. Matching address with R/W bit set is received by
the Slave setting SSP1IF bit.
4. Slave hardware generates an ACK and sets
SSP1IF.
5. SSP1IF bit is cleared by user.
6. Software reads the received address from
SSP1BUF, clearing BF.
7. R/W is set so CKP was automatically cleared
after the ACK.
8. The slave software loads the transmit data into
SSP1BUF.
9. CKP bit is set releasing SCL, allowing the mas-
ter to clock the data out of the slave.
10. SSP1IF is set after the ACK response from the
master is loaded into the ACKSTAT register.
11. SSP1IF bit is cleared.
12. The slave software checks the ACKSTAT bit to
see if the master wants to clock out more data.
13. Steps 9-13 are repeated for each transmitted
byte.
14. If the master sends a not ACK; the clock is not
held, but SSP1IF is still set.
15. The master sends a Restart condition or a Stop.
16. The slave is no longer addressed.
Note 1: If the master ACKs the clock will be
stretched.
2: ACKSTAT is the only bit updated on the
rising edge of SCL (9th) rather than the
falling.
PIC12F/LF1822/16F/LF1823
DS41413A-page 248 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-18: I2C SLAVE, 7-BIT ADDRESS, TRANSMISSION (AHEN = 0)
Receiving Address Automatic Transmitting Data Automatic Transmitting Data
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
SDA
SCL
SSP1IF
BF
CKP
ACKSTAT
R/W
D/A
S
P
Received address
When R/W is set
R/W is copied from the
Indicates an address
is read from SSP1BUF
SCL is always
held low after 9th SCL
falling edge
matching address byte
has been received
Masters not ACK
is copied to
ACKSTAT
CKP is not
held for not
ACK
BF is automatically
cleared after 8th falling
edge of SCL
Data to transmit is
loaded into SSP1BUF
Set by software
Cleared by software
ACK
ACK
ACK
R/W = 1
SP
Master sends
Stop condition
2010 Microchip Technology Inc. Preliminary DS41413A-page 249
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24.5.3.3 7-bit Transmission with Address
Hold Enabled
Setting the AHEN bit of the SSP1CON3 register
enables additional clock stretching and interrupt gen-
eration after the 8th falling edge of a received match-
ing address. Once a matching address has been
clocked in, CKP is cleared and the SSP1IF interrupt is
set.
Figure 24-18 displays a standard waveform of a 7-bit
Address Slave Transmission with AHEN enabled.
1. Bus starts Idle.
2. Master sends Start condition; the S bit of
SSP1STAT is set; SSP1IF is set if inter-
rupt-on-Start detect is enabled.
3. Master sends matching address with R/W bit
set. After the 8th falling edge of the SCL line the
CKP bit is cleared and SSP1IF interrupt is gen-
erated.
4. Slave software clears SSP1IF.
5. Slave software reads ACKTIM bit of SSP1CON3
register, and R/W and D/A of the SSP1STAT
register to determine the source of the interrupt.
6. Slave reads the address value from the
SSP1BUF register clearing the BF bit.
7. Slave software decides from this information if it
wishes to ACK or not ACK and sets ACKDT bit
of the SSP1CON2 register accordingly.
8. Slave sets the CKP bit releasing SCL.
9. Master clocks in the ACK value from the slave.
10. Slave hardware automatically clears the CKP bit
and sets SSP1IF after the ACK if the R/W bit is
set.
11. Slave software clears SSP1IF.
12. Slave loads value to transmit to the master into
SSP1BUF setting the BF bit.
13. Slave sets CKP bit releasing the clock.
14. Master clocks out the data from the slave and
sends an ACK value on the 9th SCL pulse.
15. Slave hardware copies the ACK value into the
ACKSTAT bit of the SSP1CON2 register.
16. Steps 10-15 are repeated for each byte transmit-
ted to the master from the slave.
17. If the master sends a not ACK the slave
releases the bus, allowing the master to send a
Stop and end the communication.
Note: SSP1BUF cannot be loaded until after the
ACK.
Note: Master must send a not ACK on the last byte
to ensure that the slave releases the SCL
line to receive a Stop.
PIC12F/LF1822/16F/LF1823
DS41413A-page 250 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-19: I2C SLAVE, 7-BIT ADDRESS, TRANSMISSION (AHEN = 1)
Receiving Address Automatic Transmitting Data Automatic Transmitting Data
A7 A6 A5 A4 A3 A2 A1 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
SDA
SCL
SSP1IF
BF
ACKDT
ACKSTAT
CKP
R/W
D/A
Received address
is read from SSP1BUF
BF is automatically
cleared after 8th falling
edge of SCL
Data to transmit is
loaded into SSP1BUF
Cleared by software
Slave clears
ACKDT to ACK
address
Master’s ACK
response is copied
to SSP1STAT
CKP not cleared
after not ACK
Set by software,
releases SCL
ACKTIM is cleared
on 9th rising edge of SCL
ACKTIM is set on 8th falling
edge of SCL
When AHEN = 1;
CKP is cleared by hardware
after receiving matching
address.
When R/W = 1;
CKP is always
cleared after ACK
SP
Master sends
Stop condition
ACK
R/W = 1
Master releases SDA
to slave for ACK sequence
ACK
ACK
ACKTIM
2010 Microchip Technology Inc. Preliminary DS41413A-page 251
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24.5.4 SLAVE MODE 10-BIT ADDRESS
RECEPTION
This section describes a standard sequence of events
for the MSSP1 module configured as an I2C Slave in
10-bit Addressing mode.
Figure 24-19 is used as a visual reference for this
description.
This is a step by step process of what must be done by
slave software to accomplish I2C communication.
1. Bus starts Idle.
2. Master sends Start condition; S bit of
SSP1STAT is set; SSP1IF is set if inter-
rupt-on-Start detect is enabled.
3. Master sends matching high address with R/W
bit clear; UA bit of the SSP1STAT register is set.
4. Slave sends ACK and SSP1IF is set.
5. Software clears the SSP1IF bit.
6. Software reads received address from
SSP1BUF clearing the BF flag.
7. Slave loads low address into SSP1ADD,
releasing SCL.
8. Master sends matching low address byte to the
Slave; UA bit is set.
9. Slave sends ACK and SSP1IF is set.
10. Slave clears SSP1IF.
11. Slave reads the received matching address
from SSP1BUF clearing BF.
12. Slave loads high address into SSP1ADD.
13. Master clocks a data byte to the slave and
clocks out the slaves ACK on the 9th SCL pulse;
SSP1IF is set.
14. If SEN bit of SSP1CON2 is set, CKP is cleared
by hardware and the clock is stretched.
15. Slave clears SSP1IF.
16. Slave reads the received byte from SSP1BUF
clearing BF.
17. If SEN is set the slave sets CKP to release the
SCL.
18. Steps 13-17 repeat for each received byte.
19. Master sends Stop to end the transmission.
24.5.5 10-BIT ADDRESSING WITH ADDRESS OR
DATA HOLD
Reception using 10-bit addressing with AHEN or
DHEN set is the same as with 7-bit modes. The only
difference is the need to update the SSP1ADD register
using the UA bit. All functionality, specifically when the
CKP bit is cleared and SCL line is held low are the
same. Figure 24-20 can be used as a reference of a
slave in 10-bit addressing with AHEN set.
Figure 24-21 shows a standard waveform for a slave
transmitter in 10-bit Addressing mode.
Note: Updates to the SSP1ADD register are not
allowed until after the ACK sequence.
Note: If the low address does not match, SSP1IF
and UA are still set so that the slave software
can set SSP1ADD back to the high address.
BF is not set because there is no match.
CKP is unaffected.
PIC12F/LF1822/16F/LF1823
DS41413A-page 252 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-20: I2C SLAVE, 10-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 0, DHEN = 0)
SSP1IF
Receive First Address Byte
ACK
Receive Second Address Byte
ACK
Receive Data
ACK
Receive Data
ACK
11110
A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5 D4 D3 D2 D1 D0
SDA
SCL
UA
CKP
12345678912345678
912345678
9123456789P
Master sends
Stop condition
Cleared by software
Receive address is
Software updates SSP1ADD
Data is read
SCL is held low
Set by software,
while CKP =
0
from SSP1BUF
releasing SCL
When SEN =
1
;
CKP is cleared after
9th falling edge of received byte
read from SSP1BUF
and releases SCL
When UA =
1
;
If address matches
Set by hardware
on 9th falling edge
SSP1ADD it is loaded into
SSP1BUF
SCL is held low
S
BF
2010 Microchip Technology Inc. Preliminary DS41413A-page 253
PIC12F/LF1822/16F/LF1823
FIGURE 24-21: I2C SLAVE, 10-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 1, DHEN = 0)
Receive First Address Byte
UA
Receive Second Address Byte
UA
Receive Data
ACK
Receive Data
1 1 1 1 0
A9 A8 A7 A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 D7 D6 D5SDA
SCL
SSP1IF
BF
ACKDT
UA
CKP
ACKTIM
12345678 9
S
ACK
ACK
12345678 912345678 91
2
SSP1BUF
is read from
Received data
SSP1BUF can be
read anytime before
the next received byte
Cleared by software
falling edge of SCL
not allowed until 9th
Update to SSP1ADD is
Set CKP with software
releases SCL
SCL
clears UA and releases
Update of SSP1ADD,
Set by hardware
on 9th falling edge
Slave software clears
ACKDT to ACK
the received byte
If when AHEN = 1;
on the 8th falling edge
of SCL of an address
byte, CKP is cleared
ACKTIM is set by hardware
on 8th falling edge of SCL
Cleared by software
R/W = 0
PIC12F/LF1822/16F/LF1823
DS41413A-page 254 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-22: I2C SLAVE, 10-BIT ADDRESS, TRANSMISSION (SEN = 0, AHEN = 0, DHEN = 0)
Receiving Address
ACK
Receiving Second Address Byte
Sr
Receive First Address Byte
ACK
Transmitting Data Byte
1 1 1 1 0
A9 A8 A7 A6 A5 A4 A3 A2 A1 A0
1 1 1 1 0
A9 A8 D7 D6 D5 D4 D3 D2 D1 D0SDA
SCL
SSP1IF
BF
UA
CKP
R/W
D/A
123456789 123456789 1234 56789 123456789
ACK = 1
P
Master sends
Stop condition
Master sends
not ACK
Master sends
Restart event
ACK
R/W = 0
S
Cleared by software
After SSP1ADD is
updated, UA is cleared
and SCL is released
High address is loaded
Received address is Data to transmit is
Set by software
Indicates an address
When R/W = 1;
R/W is copied from the
Set by hardware
UA indicates SSP1ADD
SSP1BUF loaded
with received address
must be updated
has been received
loaded into SSP1BUF
releases SCL
Masters not ACK
is copied
matching address byte
CKP is cleared on
9th falling edge of SCL
read from SSP1BUF
back into SSP1ADD
ACKSTAT
Set by hardware
2010 Microchip Technology Inc. Preliminary DS41413A-page 255
PIC12F/LF1822/16F/LF1823
24.5.6 CLOCK STRETCHING
Clock stretching occurs when a device on the bus
holds the SCL line low effectively pausing communica-
tion. The slave may stretch the clock to allow more
time to handle data or prepare a response for the mas-
ter device. A master device is not concerned with
stretching as anytime it is active on the bus and not
transferring data it is stretching. Any stretching done
by a slave is invisible to the master software and han-
dled by the hardware that generates SCL.
The CKP bit of the SSP1CON1 register is used to con-
trol stretching in software. Any time the CKP bit is
cleared, the module will wait for the SCL line to go low
and then hold it. Setting CKP will release SCL and
allow more communication.
24.5.6.1 Normal Clock Stretching
Following an ACK if the R/W bit of SSP1STAT is set, a
read request, the slave hardware will clear CKP. This
allows the slave time to update SSP1BUF with data to
transfer to the master. If the SEN bit of SSP1CON2 is
set, the slave hardware will always stretch the clock
after the ACK sequence. Once the slave is ready; CKP
is set by software and communication resumes.
24.5.6.2 10-bit Addressing Mode
In 10-bit Addressing mode, when the UA bit is set, the
clock is always stretched. This is the only time the SCL
is stretched without CKP being cleared. SCL is
released immediately after a write to SSP1ADD.
24.5.6.3 Byte NACKing
When AHEN bit of SSP1CON3 is set; CKP is cleared
by hardware after the 8th falling edge of SCL for a
received matching address byte. When DHEN bit of
SSP1CON3 is set; CKP is cleared after the 8th falling
edge of SCL for received data.
Stretching after the 8th falling edge of SCL allows the
slave to look at the received address or data and
decide if it wants to ACK the received data.
24.5.7 CLOCK SYNCHRONIZATION AND
THE CKP BIT
Any time the CKP bit is cleared, the module will wait
for the SCL line to go low and then hold it. However,
clearing the CKP bit will not assert the SCL output low
until the SCL output is already sampled low. There-
fore, the CKP bit will not assert the SCL line until an
external I2C master device has already asserted the
SCL line. The SCL output will remain low until the CKP
bit is set and all other devices on the I2C bus have
released SCL. This ensures that a write to the CKP bit
will not violate the minimum high time requirement for
SCL (see Figure 24-22).
FIGURE 24-23: CLOCK SYNCHRONIZATION TIMING
Note 1: The BF bit has no effect on if the clock will
be stretched or not. This is different than
previous versions of the module that
would not stretch the clock, clear CKP, if
SSP1BUF was read before the 9th falling
edge of SCL.
2: Previous versions of the module did not
stretch the clock for a transmission if
SSP1BUF was loaded before the 9th fall-
ing edge of SCL. It is now always cleared
for read requests.
Note: Previous versions of the module did not
stretch the clock if the second address byte
did not match.
SDA
SCL
DX ‚ – 1DX
WR
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SSP1CON1
CKP
Master device
releases clock
Master device
asserts clock
PIC12F/LF1822/16F/LF1823
DS41413A-page 256 Preliminary 2010 Microchip Technology Inc.
24.5.8 GENERAL CALL ADDRESS SUPPORT
The addressing procedure for the I2C bus is such that
the first byte after the Start condition usually deter-
mines which device will be the slave addressed by the
master device. The exception is the general call
address which can address all devices. When this
address is used, all devices should, in theory, respond
with an acknowledge.
The general call address is a reserved address in the
I2C protocol, defined as address 0x00. When the
GCEN bit of the SSP1CON2 register is set, the slave
module will automatically ACK the reception of this
address regardless of the value stored in SSP1ADD.
After the slave clocks in an address of all zeros with
the R/W bit clear, an interrupt is generated and slave
software can read SSP1BUF and respond.
Figure 24-23 shows a general call reception
sequence.
In 10-bit Address mode, the UA bit will not be set on
the reception of the general call address. The slave
will prepare to receive the second byte as data, just as
it would in 7-bit mode.
If the AHEN bit of the SSP1CON3 register is set, just
as with any other address reception, the slave hard-
ware will stretch the clock after the 8th falling edge of
SCL. The slave must then set its ACKDT value and
release the clock with communication progressing as it
would normally.
FIGURE 24-24: SLAVE MODE GENERAL CALL ADDRESS SEQUENCE
24.5.9 SSP1 MASK REGISTER
An SSP1 Mask (SSP1MSK) register (Register 24-5) is
available in I2C Slave mode as a mask for the value
held in the SSP1SR register during an address
comparison operation. A zero (‘0’) bit in the SSP1MSK
register has the effect of making the corresponding bit
of the received address a “don’t care”.
This register is reset to all ‘1’s upon any Reset
condition and, therefore, has no effect on standard
SSP1 operation until written with a mask value.
The SSP1 Mask register is active during:
• 7-bit Address mode: address compare of A<7:1>.
• 10-bit Address mode: address compare of A<7:0>
only. The SSP1 mask has no effect during the
reception of the first (high) byte of the address.
SDA
SCL
S
SSP1IF
BF (SSP1STAT<0>)
Cleared by software
SSP1BUF is read
R/W = 0
ACK
General Call Address
Address is compared to General Call Address
Receiving Data ACK
123456789123456789
D7 D6 D5 D4 D3 D2 D1 D0
after ACK, set interrupt
GCEN (SSP1CON2<7>)
’1’
2010 Microchip Technology Inc. Preliminary DS41413A-page 257
PIC12F/LF1822/16F/LF1823
24.6 I2C MASTER MODE
Master mode is enabled by setting and clearing the
appropriate SSP1M bits in the SSP1CON1 register and
by setting the SSP1EN bit. In Master mode, the SCL
and SDA lines are set as inputs and are manipulated by
the MSSP1 hardware.
Master mode of operation is supported by interrupt
generation on the detection of the Start and Stop con-
ditions. The Stop (P) and Start (S) bits are cleared from
a Reset or when the MSSP1 module is disabled. Con-
trol of the I2C bus may be taken when the P bit is set,
or the bus is Idle.
In Firmware Controlled Master mode, user code
conducts all I2C bus operations based on Start and
Stop bit condition detection. Start and Stop condition
detection is the only active circuitry in this mode. All
other communication is done by the user software
directly manipulating the SDA and SCL lines.
The following events will cause the SSP1 Interrupt Flag
bit, SSP1IF, to be set (SSP1 interrupt, if enabled):
• Start condition detected
• Stop condition detected
• Data transfer byte transmitted/received
• Acknowledge transmitted/received
• Repeated Start generated
24.6.1 I2C MASTER MODE OPERATION
The master device generates all of the serial clock
pulses and the Start and Stop conditions. A transfer is
ended with a Stop condition or with a Repeated Start
condition. Since the Repeated Start condition is also
the beginning of the next serial transfer, the I2C bus will
not be released.
In Master Transmitter mode, serial data is output
through SDA, while SCL outputs the serial clock. The
first byte transmitted contains the slave address of the
receiving device (7 bits) and the Read/Write (R/W) bit.
In this case, the R/W bit will be logic ‘0’. Serial data is
transmitted 8 bits at a time. After each byte is transmit-
ted, an Acknowledge bit is received. Start and Stop
conditions are output to indicate the beginning and the
end of a serial transfer.
In Master Receive mode, the first byte transmitted con-
tains the slave address of the transmitting device
(7 bits) and the R/W bit. In this case, the R/W bit will be
logic ‘1’. Thus, the first byte transmitted is a 7-bit slave
address followed by a ‘1’ to indicate the receive bit.
Serial data is received via SDA, while SCL outputs the
serial clock. Serial data is received 8 bits at a time. After
each byte is received, an Acknowledge bit is transmit-
ted. Start and Stop conditions indicate the beginning
and end of transmission.
A Baud Rate Generator is used to set the clock
frequency output on SCL. See Section 24.7 “Baud
Rate Generator” for more detail.
Note 1: The MSSP1 module, when configured in
I2C Master mode, does not allow queue-
ing of events. For instance, the user is not
allowed to initiate a Start condition and
immediately write the SSP1BUF register
to initiate transmission before the Start
condition is complete. In this case, the
SSP1BUF will not be written to and the
WCOL bit will be set, indicating that a write
to the SSP1BUF did not occur
2: When in Master mode, Start/Stop detec-
tion is masked and an interrupt is gener-
ated when the SEN/PEN bit is cleared and
the generation is complete.
PIC12F/LF1822/16F/LF1823
DS41413A-page 258 Preliminary 2010 Microchip Technology Inc.
24.6.2 CLOCK ARBITRATION
Clock arbitration occurs when the master, during any
receive, transmit or Repeated Start/Stop condition,
releases the SCL pin (SCL allowed to float high). When
the SCL pin is allowed to float high, the Baud Rate Gen-
erator (BRG) is suspended from counting until the SCL
pin is actually sampled high. When the SCL pin is sam-
pled high, the Baud Rate Generator is reloaded with
the contents of SSP1ADD<7:0> and begins counting.
This ensures that the SCL high time will always be at
least one BRG rollover count in the event that the clock
is held low by an external device (Figure 24-25).
FIGURE 24-25: BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION
24.6.3 WCOL STATUS FLAG
If the user writes the SSP1BUF when a Start, Restart,
Stop, Receive or Transmit sequence is in progress, the
WCOL is set and the contents of the buffer are
unchanged (the write doesn’t occur). Any time the
WCOL bit is set it indicates that an action on SSP1BUF
was attempted while the module was not Idle.
SDA
SCL
SCL deasserted but slave holds
DX ‚ – 1DX
BRG
SCL is sampled high, reload takes
place and BRG starts its count
03h 02h 01h 00h (hold off) 03h 02h
Reload
BRG
Value
SCL low (clock arbitration)
SCL allowed to transition high
BRG decrements on
Q2 and Q4 cycles
Note: Because queueing of events is not
allowed, writing to the lower 5 bits of
SSP1CON2 is disabled until the Start
condition is complete.
2010 Microchip Technology Inc. Preliminary DS41413A-page 259
PIC12F/LF1822/16F/LF1823
24.6.4 I2C MASTER MODE START
CONDITION TIMING
To initiate a Start condition, the user sets the Start
Enable bit, SEN bit of the SSP1CON2 register. If the
SDA and SCL pins are sampled high, the Baud Rate
Generator is reloaded with the contents of
SSP1ADD<7:0> and starts its count. If SCL and SDA
are both sampled high when the Baud Rate Generator
times out (TBRG), the SDA pin is driven low. The action
of the SDA being driven low while SCL is high is the
Start condition and causes the S bit of the SSP1STAT1
register to be set. Following this, the Baud Rate Gen-
erator is reloaded with the contents of SSP1ADD<7:0>
and resumes its count. When the Baud Rate Genera-
tor times out (TBRG), the SEN bit of the SSP1CON2
register will be automatically cleared by hardware; the
Baud Rate Generator is suspended, leaving the SDA
line held low and the Start condition is complete.
FIGURE 24-26: FIRST START BIT TIMING
Note 1: If at the beginning of the Start condition,
the SDA and SCL pins are already sam-
pled low, or if during the Start condition,
the SCL line is sampled low before the
SDA line is driven low, a bus collision
occurs, the Bus Collision Interrupt Flag,
BCL1IF, is set, the Start condition is
aborted and the I2C module is reset into its
Idle state.
2: The Philips I2C Specification states that a
bus collision cannot occur on a Start.
SDA
SCL
S
TBRG
1st bit 2nd bit
TBRG
SDA = 1, At completion of Start bit,
SCL = 1
Write to SSP1BUF occurs here
TBRG
hardware clears SEN bit
TBRG
Write to SEN bit occurs here Set S bit (SSP1STAT<3>)
and sets SSP1IF bit
PIC12F/LF1822/16F/LF1823
DS41413A-page 260 Preliminary 2010 Microchip Technology Inc.
24.6.5 I2C MASTER MODE REPEATED
START CONDITION TIMING
A Repeated Start condition occurs when the RSEN bit
of the SSP1CON2 register is programmed high and the
Master state machine is no longer active. When the
RSEN bit is set, the SCL pin is asserted low. When the
SCL pin is sampled low, the Baud Rate Generator is
loaded and begins counting. The SDA pin is released
(brought high) for one Baud Rate Generator count
(TBRG). When the Baud Rate Generator times out, if
SDA is sampled high, the SCL pin will be deasserted
(brought high). When SCL is sampled high, the Baud
Rate Generator is reloaded and begins counting. SDA
and SCL must be sampled high for one TBRG. This
action is then followed by assertion of the SDA pin
(SDA = 0) for one TBRG while SCL is high. SCL is
asserted low. Following this, the RSEN bit of the
SSP1CON2 register will be automatically cleared and
the Baud Rate Generator will not be reloaded, leaving
the SDA pin held low. As soon as a Start condition is
detected on the SDA and SCL pins, the S bit of the
SSP1STAT register will be set. The SSP1IF bit will not
be set until the Baud Rate Generator has timed out.
FIGURE 24-27: REPEAT START CONDITION WAVEFORM
Note 1: If RSEN is programmed while any other
event is in progress, it will not take effect.
2: A bus collision during the Repeated Start
condition occurs if:
• SDA is sampled low when SCL
goes from low-to-high.
• SCL goes low before SDA is
asserted low. This may indicate that
another master is attempting to
transmit a data ‘1’.
SDA
SCL
Repeated Start
Write to SSP1CON2
Write to SSP1BUF occurs here
At completion of Start bit,
hardware clears RSEN bit
1st bit
S bit set by hardware
TBRG
TBRG
SDA = 1,SDA = 1,
SCL (no change) SCL = 1
occurs here
TBRG TBRG TBRG
and sets SSP1IF
Sr
2010 Microchip Technology Inc. Preliminary DS41413A-page 261
PIC12F/LF1822/16F/LF1823
24.6.6 I2C MASTER MODE TRANSMISSION
Transmission of a data byte, a 7-bit address or the
other half of a 10-bit address is accomplished by simply
writing a value to the SSP1BUF register. This action will
set the Buffer Full flag bit, BF, and allow the Baud Rate
Generator to begin counting and start the next trans-
mission. Each bit of address/data will be shifted out
onto the SDA pin after the falling edge of SCL is
asserted. SCL is held low for one Baud Rate Generator
rollover count (TBRG). Data should be valid before SCL
is released high. When the SCL pin is released high, it
is held that way for TBRG. The data on the SDA pin
must remain stable for that duration and some hold
time after the next falling edge of SCL. After the eighth
bit is shifted out (the falling edge of the eighth clock),
the BF flag is cleared and the master releases SDA.
This allows the slave device being addressed to
respond with an ACK bit during the ninth bit time if an
address match occurred, or if data was received prop-
erly. The status of ACK is written into the ACKSTAT bit
on the rising edge of the ninth clock. If the master
receives an Acknowledge, the Acknowledge Status bit,
ACKSTAT, is cleared. If not, the bit is set. After the ninth
clock, the SSP1IF bit is set and the master clock (Baud
Rate Generator) is suspended until the next data byte
is loaded into the SSP1BUF, leaving SCL low and SDA
unchanged (Figure 24-27).
After the write to the SSP1BUF, each bit of the address
will be shifted out on the falling edge of SCL until all
seven address bits and the R/W bit are completed. On
the falling edge of the eighth clock, the master will
release the SDA pin, allowing the slave to respond with
an Acknowledge. On the falling edge of the ninth clock,
the master will sample the SDA pin to see if the address
was recognized by a slave. The status of the ACK bit is
loaded into the ACKSTAT Status bit of the SSP1CON2
register. Following the falling edge of the ninth clock
transmission of the address, the SSP1IF is set, the BF
flag is cleared and the Baud Rate Generator is turned
off until another write to the SSP1BUF takes place,
holding SCL low and allowing SDA to float.
24.6.6.1 BF Status Flag
In Transmit mode, the BF bit of the SSP1STAT register
is set when the CPU writes to SSP1BUF and is cleared
when all 8 bits are shifted out.
24.6.6.2 WCOL Status Flag
If the user writes the SSP1BUF when a transmit is
already in progress (i.e., SSP1SR is still shifting out a
data byte), the WCOL is set and the contents of the buf-
fer are unchanged (the write doesn’t occur).
WCOL must be cleared by software before the next
transmission.
24.6.6.3 ACKSTAT Status Flag
In Transmit mode, the ACKSTAT bit of the SSP1CON2
register is cleared when the slave has sent an Acknowl-
edge (ACK =0) and is set when the slave does not
Acknowledge (ACK =1). A slave sends an Acknowl-
edge when it has recognized its address (including a
general call), or when the slave has properly received
its data.
24.6.6.4 Typical transmit sequence:
1. The user generates a Start condition by setting
the SEN bit of the SSP1CON2 register.
2. SSP1IF is set by hardware on completion of the
Start.
3. SSP1IF is cleared by software.
4. The MSSP1 module will wait the required start
time before any other operation takes place.
5. The user loads the SSP1BUF with the slave
address to transmit.
6. Address is shifted out the SDA pin until all 8 bits
are transmitted. Transmission begins as soon
as SSP1BUF is written to.
7. The MSSP1 module shifts in the ACK bit from
the slave device and writes its value into the
ACKSTAT bit of the SSP1CON2 register.
8. The MSSP1 module generates an interrupt at
the end of the ninth clock cycle by setting the
SSP1IF bit.
9. The user loads the SSP1BUF with eight bits of
data.
10. Data is shifted out the SDA pin until all 8 bits are
transmitted.
11. The MSSP1 module shifts in the ACK bit from
the slave device and writes its value into the
ACKSTAT bit of the SSP1CON2 register.
12. Steps 8-11 are repeated for all transmitted data
bytes.
13. The user generates a Stop or Restart condition
by setting the PEN or RSEN bits of the
SSP1CON2 register. Interrupt is generated
once the Stop/Restart condition is complete.
PIC12F/LF1822/16F/LF1823
DS41413A-page 262 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-28: I2C MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS)
SDA
SCL
SSP1IF
BF (SSP1STAT<0>)
SEN
A7 A6 A5 A4 A3 A2 A1 ACK = 0D7 D6 D5 D4 D3 D2 D1 D0
ACK
Transmitting Data or Second Half
R/W = 0Transmit Address to Slave
123456789 123456789 P
Cleared by software service routine
SSP1BUF is written by software
from SSP1 interrupt
After Start condition, SEN cleared by hardware
S
SSP1BUF written with 7-bit address and R/W
start transmit
SCL held low
while CPU
responds to SSP1IF
SEN = 0
of 10-bit Address
Write SSP1CON2<0> SEN = 1
Start condition begins From slave, clear ACKSTAT bit SSP1CON2<6>
ACKSTAT in
SSP1CON2 = 1
Cleared by software
SSP1BUF written
PEN
R/W
Cleared by software
2010 Microchip Technology Inc. Preliminary DS41413A-page 263
PIC12F/LF1822/16F/LF1823
24.6.7 I2C MASTER MODE RECEPTION
Master mode reception is enabled by programming the
Receive Enable bit, RCEN bit of the SSP1CON2
register.
The Baud Rate Generator begins counting and on each
rollover, the state of the SCL pin changes
(high-to-low/low-to-high) and data is shifted into the
SSP1SR. After the falling edge of the eighth clock, the
receive enable flag is automatically cleared, the con-
tents of the SSP1SR are loaded into the SSP1BUF, the
BF flag bit is set, the SSP1IF flag bit is set and the Baud
Rate Generator is suspended from counting, holding
SCL low. The MSSP1 is now in Idle state awaiting the
next command. When the buffer is read by the CPU,
the BF flag bit is automatically cleared. The user can
then send an Acknowledge bit at the end of reception
by setting the Acknowledge Sequence Enable, ACKEN
bit of the SSP1CON2 register.
24.6.7.1 BF Status Flag
In receive operation, the BF bit is set when an address
or data byte is loaded into SSP1BUF from SSP1SR. It
is cleared when the SSP1BUF register is read.
24.6.7.2 SSP1OV Status Flag
In receive operation, the SSP1OV bit is set when 8 bits
are received into the SSP1SR and the BF flag bit is
already set from a previous reception.
24.6.7.3 WCOL Status Flag
If the user writes the SSP1BUF when a receive is
already in progress (i.e., SSP1SR is still shifting in a
data byte), the WCOL bit is set and the contents of the
buffer are unchanged (the write doesn’t occur).
24.6.7.4 Typical Receive Sequence:
1. The user generates a Start condition by setting
the SEN bit of the SSP1CON2 register.
2. SSP1IF is set by hardware on completion of the
Start.
3. SSP1IF is cleared by software.
4. User writes SSP1BUF with the slave address to
transmit and the R/W bit set.
5. Address is shifted out the SDA pin until all 8 bits
are transmitted. Transmission begins as soon
as SSP1BUF is written to.
6. The MSSP1 module shifts in the ACK bit from
the slave device and writes its value into the
ACKSTAT bit of the SSP1CON2 register.
7. The MSSP1 module generates an interrupt at
the end of the ninth clock cycle by setting the
SSP1IF bit.
8. User sets the RCEN bit of the SSP1CON2 regis-
ter and the Master clocks in a byte from the slave.
9. After the 8th falling edge of SCL, SSP1IF and
BF are set.
10. Master clears SSP1IF and reads the received
byte from SSP1UF, clears BF.
11. Master sets ACK value sent to slave in ACKDT
bit of the SSP1CON2 register and initiates the
ACK by setting the ACKEN bit.
12. Masters ACK is clocked out to the Slave and
SSP1IF is set.
13. User clears SSP1IF.
14. Steps 8-13 are repeated for each received byte
from the slave.
15. Master sends a not ACK or Stop to end
communication.
Note: The MSSP1 module must be in an Idle
state before the RCEN bit is set or the
RCEN bit will be disregarded.
PIC12F/LF1822/16F/LF1823
DS41413A-page 264 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-29: I2C MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS)
P
9
87
6
5
D0
D1
D2
D3D4
D5
D6D7
S
A7 A6 A5 A4 A3 A2 A1
SDA
SCL 12345678912345678 9 1234
Bus master
terminates
transfer
ACK
Receiving Data from Slave
Receiving Data from Slave
D0
D1
D2
D3D4
D5
D6D7
ACK
R/W = 0
Transmit Address to Slave
SSP1IF
BF
ACK is not sent
Write to SSP1CON2<0>(SEN = 1),
Write to SSP1BUF occurs here, ACK from Slave
Master configured as a receiver
by programming SSP1CON2<3> (RCEN = 1)
PEN bit = 1
written here
Data shifted in on falling edge of CLK
Cleared by software
start XMIT
SEN = 0
SSP1OV
SDA = 0, SCL = 1
while CPU
(SSP1STAT<0>)
ACK
Cleared by software
Cleared by software
Set SSP1IF interrupt
at end of receive
Set P bit
(SSP1STAT<4>)
and SSP1IF
Cleared in
software
ACK from Master
Set SSP1IF at end
Set SSP1IF interrupt
at end of Acknowledge
sequence
Set SSP1IF interrupt
at end of Acknow-
ledge sequence
of receive
Set ACKEN, start Acknowledge sequence
SSP1OV is set because
SSP1BUF is still full
SDA = ACKDT = 1
RCEN cleared
automatically
RCEN = 1, start
next receive
Write to SSP1CON2<4>
to start Acknowledge sequence
SDA = ACKDT (SSP1CON2<5>) = 0
RCEN cleared
automatically
responds to SSP1IF
ACKEN
begin Start condition
Cleared by software
SDA = ACKDT = 0
Last bit is shifted into SSP1SR and
contents are unloaded into SSP1BUF
RCEN
Master configured as a receiver
by programming SSP1CON2<3> (RCEN = 1)
RCEN cleared
automatically
ACK from Master
SDA\ = ACKDT = 0 RCEN cleared
automatically
2010 Microchip Technology Inc. Preliminary DS41413A-page 265
PIC12F/LF1822/16F/LF1823
24.6.8 ACKNOWLEDGE SEQUENCE
TIMING
An Acknowledge sequence is enabled by setting the
Acknowledge Sequence Enable bit, ACKEN bit of the
SSP1CON2 register. When this bit is set, the SCL pin is
pulled low and the contents of the Acknowledge data bit
are presented on the SDA pin. If the user wishes to gen-
erate an Acknowledge, then the ACKDT bit should be
cleared. If not, the user should set the ACKDT bit before
starting an Acknowledge sequence. The Baud Rate
Generator then counts for one rollover period (TBRG)
and the SCL pin is deasserted (pulled high). When the
SCL pin is sampled high (clock arbitration), the Baud
Rate Generator counts for TBRG. The SCL pin is then
pulled low. Following this, the ACKEN bit is automatically
cleared, the Baud Rate Generator is turned off and the
MSSP1 module then goes into Idle mode
(Figure 24-29).
24.6.8.1 WCOL Status Flag
If the user writes the SSP1BUF when an Acknowledge
sequence is in progress, then WCOL is set and the
contents of the buffer are unchanged (the write doesn’t
occur).
24.6.9 STOP CONDITION TIMING
A Stop bit is asserted on the SDA pin at the end of a
receive/transmit by setting the Stop Sequence Enable
bit, PEN bit of the SSP1CON2 register. At the end of a
receive/transmit, the SCL line is held low after the
falling edge of the ninth clock. When the PEN bit is set,
the master will assert the SDA line low. When the SDA
line is sampled low, the Baud Rate Generator is
reloaded and counts down to ‘0’. When the Baud Rate
Generator times out, the SCL pin will be brought high
and one TBRG (Baud Rate Generator rollover count)
later, the SDA pin will be deasserted. When the SDA
pin is sampled high while SCL is high, the P bit of the
SSP1STAT register is set. A TBRG later, the PEN bit is
cleared and the SSP1IF bit is set (Figure 24-30).
24.6.9.1 WCOL Status Flag
If the user writes the SSP1BUF when a Stop sequence
is in progress, then the WCOL bit is set and the
contents of the buffer are unchanged (the write doesn’t
occur).
FIGURE 24-30: ACKNOWLEDGE SEQUENCE WAVEFORM
Note: TBRG = one Baud Rate Generator period.
SDA
SCL
SSP1IF set at
Acknowledge sequence starts here,
write to SSP1CON2 ACKEN automatically cleared
Cleared in
TBRG TBRG
the end of receive
8
ACKEN = 1, ACKDT = 0
D0
9
SSP1IF
software SSP1IF set at the end
of Acknowledge sequence
Cleared in
software
ACK
PIC12F/LF1822/16F/LF1823
DS41413A-page 266 Preliminary 2010 Microchip Technology Inc.
FIGURE 24-31: STOP CONDITION RECEIVE OR TRANSMIT MODE
24.6.10 SLEEP OPERATION
While in Sleep mode, the I2C slave module can receive
addresses or data and when an address match or
complete byte transfer occurs, wake the processor
from Sleep (if the MSSP1 interrupt is enabled).
24.6.11 EFFECTS OF A RESET
A Reset disables the MSSP1 module and terminates
the current transfer.
24.6.12 MULTI-MASTER MODE
In Multi-Master mode, the interrupt generation on the
detection of the Start and Stop conditions allows the
determination of when the bus is free. The Stop (P) and
Start (S) bits are cleared from a Reset or when the
MSSP1 module is disabled. Control of the I2C bus may
be taken when the P bit of the SSP1STAT register is
set, or the bus is Idle, with both the S and P bits clear.
When the bus is busy, enabling the SSP interrupt will
generate the interrupt when the Stop condition occurs.
In multi-master operation, the SDA line must be
monitored for arbitration to see if the signal level is the
expected output level. This check is performed by
hardware with the result placed in the BCL1IF bit.
The states where arbitration can be lost are:
• Address Transfer
• Data Transfer
• A Start Condition
• A Repeated Start Condition
• An Acknowledge Condition
24.6.13 MULTI -MASTER COMMUNICATION,
BUS COLLISION AND BUS
ARBITRATION
Multi-Master mode support is achieved by bus arbitra-
tion. When the master outputs address/data bits onto
the SDA pin, arbitration takes place when the master
outputs a ‘1’ on SDA, by letting SDA float high and
another master asserts a ‘0’. When the SCL pin floats
high, data should be stable. If the expected data on
SDA is a ‘1’ and the data sampled on the SDA pin is ‘0’,
then a bus collision has taken place. The master will set
the Bus Collision Interrupt Flag, BCL1IF, and reset the
I2C port to its Idle state (Figure 24-31).
If a transmit was in progress when the bus collision
occurred, the transmission is halted, the BF flag is
cleared, the SDA and SCL lines are deasserted and the
SSP1BUF can be written to. When the user services
the bus collision Interrupt Service Routine and if the I2C
bus is free, the user can resume communication by
asserting a Start condition.
If a Start, Repeated Start, Stop or Acknowledge condi-
tion was in progress when the bus collision occurred, the
condition is aborted, the SDA and SCL lines are deas-
serted and the respective control bits in the SSP1CON2
register are cleared. When the user services the bus col-
lision Interrupt Service Routine and if the I2C bus is free,
the user can resume communication by asserting a Start
condition.
The master will continue to monitor the SDA and SCL
pins. If a Stop condition occurs, the SSP1IF bit will be set.
A write to the SSP1BUF will start the transmission of
data at the first data bit, regardless of where the
transmitter left off when the bus collision occurred.
In Multi-Master mode, the interrupt generation on the
detection of Start and Stop conditions allows the deter-
mination of when the bus is free. Control of the I2C bus
can be taken when the P bit is set in the SSP1STAT
register, or the bus is Idle and the S and P bits are
cleared.
SCL
SDA
SDA asserted low before rising edge of clock
Write to SSP1CON2,
set PEN
Falling edge of
SCL = 1 for TBRG, followed by SDA = 1 for TBRG
9th clock
SCL brought high after TBRG
Note: TBRG = one Baud Rate Generator period.
TBRG TBRG
after SDA sampled high. P bit (SSP1STAT<4>) is set.
TBRG
to setup Stop condition
ACK
P
TBRG
PEN bit (SSP1CON2<2>) is cleared by
hardware and the SSP1IF bit is set
2010 Microchip Technology Inc. Preliminary DS41413A-page 267
PIC12F/LF1822/16F/LF1823
FIGURE 24-32: BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE
SDA
SCL
BCL1IF
SDA released
SDA line pulled low
by another source
Sample SDA. While SCL is high,
data doesn’t match what is driven
Bus collision has occurred.
Set bus collision
interrupt (BCL1IF)
by the master.
by master
Data changes
while SCL = 0
PIC12F/LF1822/16F/LF1823
DS41413A-page 268 Preliminary 2010 Microchip Technology Inc.
24.6.13.1 Bus Collision During a Start
Condition
During a Start condition, a bus collision occurs if:
a) SDA or SCL are sampled low at the beginning of
the Start condition (Figure 24-32).
b) SCL is sampled low before SDA is asserted low
(Figure 24-33).
During a Start condition, both the SDA and the SCL
pins are monitored.
If the SDA pin is already low, or the SCL pin is already
low, then all of the following occur:
• the Start condition is aborted,
• the BCL1IF flag is set and
• the MSSP1 module is reset to its Idle state
(Figure 24-32).
The Start condition begins with the SDA and SCL pins
deasserted. When the SDA pin is sampled high, the
Baud Rate Generator is loaded and counts down. If the
SCL pin is sampled low while SDA is high, a bus colli-
sion occurs because it is assumed that another master
is attempting to drive a data ‘1’ during the Start
condition.
If the SDA pin is sampled low during this count, the
BRG is reset and the SDA line is asserted early
(Figure 24-34). If, however, a ‘1’ is sampled on the SDA
pin, the SDA pin is asserted low at the end of the BRG
count. The Baud Rate Generator is then reloaded and
counts down to zero; if the SCL pin is sampled as ‘0’
during this time, a bus collision does not occur. At the
end of the BRG count, the SCL pin is asserted low.
FIGURE 24-33: BUS COLLISION DURING START CONDITION (SDA ONLY)
Note: The reason that bus collision is not a factor
during a Start condition is that no two bus
masters can assert a Start condition at the
exact same time. Therefore, one master
will always assert SDA before the other.
This condition does not cause a bus colli-
sion because the two masters must be
allowed to arbitrate the first address fol-
lowing the Start condition. If the address is
the same, arbitration must be allowed to
continue into the data portion, Repeated
Start or Stop conditions.
SDA
SCL
SEN
SDA sampled low before
SDA goes low before the SEN bit is set.
S bit and SSP1IF set because
SSP1 module reset into Idle state.
SEN cleared automatically because of bus collision.
S bit and SSP1IF set because
Set SEN, enable Start
condition if SDA = 1, SCL = 1
SDA = 0, SCL = 1.
BCL1IF
S
SSP1IF
SDA = 0, SCL = 1.
SSP1IF and BCL1IF are
cleared by software
SSP1IF and BCL1IF are
cleared by software
Set BCL1IF,
Start condition. Set BCL1IF.
2010 Microchip Technology Inc. Preliminary DS41413A-page 269
PIC12F/LF1822/16F/LF1823
FIGURE 24-34: BUS COLLISION DURING START CONDITION (SCL = 0)
FIGURE 24-35: BRG RESET DUE TO SDA ARBITRATION DURING START CONDITION
SDA
SCL
SEN bus collision occurs. Set BCL1IF.
SCL = 0 before SDA = 0,
Set SEN, enable Start
sequence if SDA = 1, SCL = 1
TBRG TBRG
SDA = 0, SCL = 1
BCL1IF
S
SSP1IF
Interrupt cleared
by software
bus collision occurs. Set BCL1IF.
SCL = 0 before BRG time-out,
’0’’0’
’0’’0’
SDA
SCL
SEN
Set S
Less than TBRG TBRG
SDA = 0, SCL = 1
BCL1IF
S
SSP1IF
S
Interrupts cleared
by software
set SSP1IF
SDA = 0, SCL = 1,
SCL pulled low after BRG
time-out
Set SSP1IF
’0’
SDA pulled low by other master.
Reset BRG and assert SDA.
Set SEN, enable Start
sequence if SDA = 1, SCL = 1
PIC12F/LF1822/16F/LF1823
DS41413A-page 270 Preliminary 2010 Microchip Technology Inc.
24.6.13.2 Bus Collision During a Repeated
Start Condition
During a Repeated Start condition, a bus collision
occurs if:
a) A low level is sampled on SDA when SCL goes
from low level to high level.
b) SCL goes low before SDA is asserted low,
indicating that another master is attempting to
transmit a data ‘1’.
When the user releases SDA and the pin is allowed to
float high, the BRG is loaded with SSP1ADD and
counts down to zero. The SCL pin is then deasserted
and when sampled high, the SDA pin is sampled.
If SDA is low, a bus collision has occurred (i.e., another
master is attempting to transmit a data ‘0’, Figure 24-35).
If SDA is sampled high, the BRG is reloaded and begins
counting. If SDA goes from high-to-low before the BRG
times out, no bus collision occurs because no two
masters can assert SDA at exactly the same time.
If SCL goes from high-to-low before the BRG times out
and SDA has not already been asserted, a bus collision
occurs. In this case, another master is attempting to
transmit a data ‘1’ during the Repeated Start condition,
see Figure 24-36.
If, at the end of the BRG time-out, both SCL and SDA
are still high, the SDA pin is driven low and the BRG is
reloaded and begins counting. At the end of the count,
regardless of the status of the SCL pin, the SCL pin is
driven low and the Repeated Start condition is
complete.
FIGURE 24-36: BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)
FIGURE 24-37: BUS COLLISION DURING REPEATED START CONDITION (CASE 2)
SDA
SCL
RSEN
BCL1IF
S
SSP1IF
Sample SDA when SCL goes high.
If SDA = 0, set BCL1IF and release SDA and SCL.
Cleared by software
’0’
’0’
SDA
SCL
BCL1IF
RSEN
S
SSP1IF
Interrupt cleared
by software
SCL goes low before SDA,
set BCL1IF. Release SDA and SCL.
TBRG TBRG
’0’
2010 Microchip Technology Inc. Preliminary DS41413A-page 271
PIC12F/LF1822/16F/LF1823
24.6.13.3 Bus Collision During a Stop
Condition
Bus collision occurs during a Stop condition if:
a) After the SDA pin has been deasserted and
allowed to float high, SDA is sampled low after
the BRG has timed out.
b) After the SCL pin is deasserted, SCL is sampled
low before SDA goes high.
The Stop condition begins with SDA asserted low.
When SDA is sampled low, the SCL pin is allowed to
float. When the pin is sampled high (clock arbitration),
the Baud Rate Generator is loaded with SSP1ADD and
counts down to 0. After the BRG times out, SDA is
sampled. If SDA is sampled low, a bus collision has
occurred. This is due to another master attempting to
drive a data ‘0’ (Figure 24-37). If the SCL pin is sampled
low before SDA is allowed to float high, a bus collision
occurs. This is another case of another master
attempting to drive a data ‘0’ (Figure 24-38).
FIGURE 24-38: BUS COLLISION DURING A STOP CONDITION (CASE 1)
FIGURE 24-39: BUS COLLISION DURING A STOP CONDITION (CASE 2)
SDA
SCL
BCL1IF
PEN
P
SSP1IF
TBRG TBRG TBRG
SDA asserted low
SDA sampled
low after TBRG,
set BCL1IF
’0’
’0’
SDA
SCL
BCL1IF
PEN
P
SSP1IF
TBRG TBRG TBRG
Assert SDA SCL goes low before SDA goes high,
set BCL1IF
’0’
’0’
PIC12F/LF1822/16F/LF1823
DS41413A-page 272 Preliminary 2010 Microchip Technology Inc.
TABLE 24-3: SUMMARY OF REGISTERS ASSOCIATED WITH I2C™ OPERATION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reset
Values on
Page
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIE2 OSFIE C2IE(1) C1IE EEIE BCL1IE ———91
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF 92
PIR2 OSFIF C2IF(1) C1IF EEIF BCL1IF — — —93
SSP1ADD ADD7 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0 278
SSP1BUF Synchronous Serial Port Receive Buffer/Transmit Register 229*
SSP1CON1 WCOL SSPOV SSPEN CKP SSPM<3:0> 275
SSP1CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 276
SSP1CON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN 277
SSP1MSK MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0 278
SSP1STAT SMP CKE D/A P S R/W UA BF 274
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used by the MSSP module in I2C™ mode.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 273
PIC12F/LF1822/16F/LF1823
24.7 BAUD RATE GENERATOR
The MSSP1 module has a Baud Rate Generator avail-
able for clock generation in both I2C and SPI Master
modes. The Baud Rate Generator (BRG) reload value
is placed in the SSP1ADD register (Register 24-6).
When a write occurs to SSP1BUF, the Baud Rate Gen-
erator will automatically begin counting down.
Once the given operation is complete, the internal clock
will automatically stop counting and the clock pin will
remain in its last state.
An internal signal “Reload” in Figure 24-39 triggers the
value from SSP1ADD to be loaded into the BRG
counter. This occurs twice for each oscillation of the
module clock line. The logic dictating when the reload
signal is asserted depends on the mode the MSSP1 is
being operated in.
Table 24-4 demonstrates clock rates based on
instruction cycles and the BRG value loaded into
SSP1ADD.
EQUATION 24-1:
FIGURE 24-40: BAUD RATE GENERATOR BLOCK DIAGRAM
TABLE 24-4: MSSP1 CLOCK RATE W/BRG
FCLOCK FOSC
SSPxADD 1+4
-------------------------------------------------=
Note: Values of 0x00, 0x01 and 0x02 are not valid
for SSP1ADD when used as a Baud Rate
Generator for I2C. This is an implementation
limitation.
FOSC FCY BRG Value FCLOCK
(2 Rollovers of BRG)
32 MHz 8 MHz 13h 400 kHz(1)
32 MHz 8 MHz 19h 308 kHz
32 MHz 8 MHz 4Fh 100 kHz
16 MHz 4 MHz 09h 400 kHz(1)
16 MHz 4 MHz 0Ch 308 kHz
16 MHz 4 MHz 27h 100 kHz
4 MHz 1 MHz 09h 100 kHz
Note 1: The I2C interface does not conform to the 400 kHz I2C specification (which applies to rates greater than
100 kHz) in all details, but may be used with care where higher rates are required by the application.
SSP1M<3:0>
BRG Down Counter
SSP1CLK FOSC/2
SSP1ADD<7:0>
SSP1M<3:0>
SCL
Reload
Control
Reload
PIC12F/LF1822/16F/LF1823
DS41413A-page 274 Preliminary 2010 Microchip Technology Inc.
REGISTER 24-1: SSP1STAT: SSP1 STATUS REGISTER
R/W-0/0 R/W-0/0 R-0/0 R-0/0 R-0/0 R-0/0 R-0/0 R-0/0
SMP CKE D/A PSR/WUA BF
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 SMP: SPI Data Input Sample bit
SPI Master mode:
1 = Input data sampled at end of data output time
0 = Input data sampled at middle of data output time
SPI Slave mode:
SMP must be cleared when SPI is used in Slave mode
In I2 C Master or Slave mode:
1 = Slew rate control disabled for standard speed mode (100 kHz and 1 MHz)
0 = Slew rate control enabled for high speed mode (400 kHz)
bit 6 CKE: SPI Clock Edge Select bit (SPI mode only)
In SPI Master or Slave mode:
1 = Transmit occurs on transition from active to Idle clock state
0 = Transmit occurs on transition from Idle to active clock state
In I2 C™ mode only:
1 = Enable input logic so that thresholds are compliant with SMBus specification
0 = Disable SMBus specific inputs
bit 5 D/A: Data/Address bit (I2C mode only)
1 = Indicates that the last byte received or transmitted was data
0 = Indicates that the last byte received or transmitted was address
bit 4 P: Stop bit
(I2C mode only. This bit is cleared when the MSSP1 module is disabled, SSP1EN is cleared.)
1 = Indicates that a Stop bit has been detected last (this bit is ‘0’ on Reset)
0 = Stop bit was not detected last
bit 3 S: Start bit
(I2C mode only. This bit is cleared when the MSSP1 module is disabled, SSP1EN is cleared.)
1 = Indicates that a Start bit has been detected last (this bit is ‘0’ on Reset)
0 = Start bit was not detected last
bit 2 R/W: Read/Write bit information (I2C mode only)
This bit holds the R/W bit information following the last address match. This bit is only valid from the address match
to the next Start bit, Stop bit, or not ACK bit.
In I2 C Slave mode:
1 = Read
0 = Write
In I2 C Master mode:
1 = Transmit is in progress
0 = Transmit is not in progress
OR-ing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSP1 is in Idle mode.
bit 1 UA: Update Address bit (10-bit I2C mode only)
1 = Indicates that the user needs to update the address in the SSP1ADD register
0 = Address does not need to be updated
bit 0 BF: Buffer Full Status bit
Receive (SPI and I2 C modes):
1 = Receive complete, SSP1BUF is full
0 = Receive not complete, SSP1BUF is empty
Transmit (I2 C mode only):
1 = Data transmit in progress (does not include the ACK and Stop bits), SSP1BUF is full
0 = Data transmit complete (does not include the ACK and Stop bits), SSP1BUF is empty
2010 Microchip Technology Inc. Preliminary DS41413A-page 275
PIC12F/LF1822/16F/LF1823
REGISTER 24-2: SSP1CON1: SSP1 CONTROL REGISTER 1
R/C/HS-0/0 R/C/HS-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
WCOL SSP1OV SSP1EN CKP SSP1M<3:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared HS = Bit is set by hardware C = User cleared
bit 7 WCOL: Write Collision Detect bit
Master mode:
1 = A write to the SSP1BUF register was attempted while the I2C conditions were not valid for a transmission to be started
0 = No collision
Slave mode:
1 = The SSP1BUF register is written while it is still transmitting the previous word (must be cleared in software)
0 = No collision
bit 6 SSP1OV: Receive Overflow Indicator bit(1)
In SPI mode:
1 = A new byte is received while the SSP1BUF register is still holding the previous data. In case of overflow, the data in SSP1SR
is lost. Overflow can only occur in Slave mode. In Slave mode, the user must read the SSP1BUF, even if only transmitting
data, to avoid setting overflow. In Master mode, the overflow bit is not set since each new reception (and transmission) is
initiated by writing to the SSP1BUF register (must be cleared in software).
0 = No overflow
In I2 C mode:
1 = A byte is received while the SSP1BUF register is still holding the previous byte. SSP1OV is a “don’t care” in Transmit
mode (must be cleared in software).
0 = No overflow
bit 5 SSP1EN: Synchronous Serial Port Enable bit
In both modes, when enabled, these pins must be properly configured as input or output
In SPI mode:
1 = Enables serial port and configures SCK, SDO, SDI and SS as the source of the serial port pins(2)
0 = Disables serial port and configures these pins as I/O port pins
In I2 C mode:
1 = Enables the serial port and configures the SDA and SCL pins as the source of the serial port pins(3)
0 = Disables serial port and configures these pins as I/O port pins
bit 4 CKP: Clock Polarity Select bit
In SPI mode:
1 = Idle state for clock is a high level
0 = Idle state for clock is a low level
In I2 C Slave mode:
SCL release control
1 = Enable clock
0 = Holds clock low (clock stretch). (Used to ensure data setup time.)
In I2 C Master mode:
Unused in this mode
bit 3-0 SSP1M<3:0>: Synchronous Serial Port Mode Select bits
0000 = SPI Master mode, clock = FOSC/4
0001 = SPI Master mode, clock = FOSC/16
0010 = SPI Master mode, clock = FOSC/64
0011 = SPI Master mode, clock = TMR2 output/2
0100 = SPI Slave mode, clock = SCK pin, SS pin control enabled
0101 = SPI Slave mode, clock = SCK pin, SS pin control disabled, SS can be used as I/O pin
0110 = I2C Slave mode, 7-bit address
0111 = I2C Slave mode, 10-bit address
1000 = I2C Master mode, clock = FOSC / (4 * (SSP1ADD+1))(4)
1001 = Reserved
1010 = SPI Master mode, clock = FOSC/(4 * (SSP1ADD+1))
1011 = I2C firmware controlled Master mode (Slave idle)
1100 = Reserved
1101 = Reserved
1110 = I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled
1111 = I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled
Note 1: In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the SSP1BUF
register.
2: When enabled, these pins must be properly configured as input or output.
3: When enabled, the SDA and SCL pins must be configured as inputs.
4: SSP1ADD values of 0, 1 or 2 are not supported for I2C Mode.
PIC12F/LF1822/16F/LF1823
DS41413A-page 276 Preliminary 2010 Microchip Technology Inc.
REGISTER 24-3: SSP1CON2: SSP1 CONTROL REGISTER 2
R/W-0/0 R-0/0 R/W-0/0 R/S/HS-0/0 R/S/HS-0/0 R/S/HS-0/0 R/S/HS-0/0 R/W/HS-0/0
GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared HC = Cleared by hardware S = User set
bit 7 GCEN: General Call Enable bit (in I2C Slave mode only)
1 = Enable interrupt when a general call address (0x00 or 00h) is received in the SSP1SR
0 = General call address disabled
bit 6 ACKSTAT: Acknowledge Status bit (in I2C mode only)
1 = Acknowledge was not received
0 = Acknowledge was received
bit 5 ACKDT: Acknowledge Data bit (in I2C mode only)
In Receive mode:
Value transmitted when the user initiates an Acknowledge sequence at the end of a receive
1 = Not Acknowledge
0 = Acknowledge
bit 4 ACKEN: Acknowledge Sequence Enable bit (in I2C Master mode only)
In Master Receive mode:
1 = Initiate Acknowledge sequence on SDA and SCL pins, and transmit ACKDT data bit.
Automatically cleared by hardware.
0 = Acknowledge sequence idle
bit 3 RCEN: Receive Enable bit (in I2C Master mode only)
1 = Enables Receive mode for I2C
0 = Receive idle
bit 2 PEN: Stop Condition Enable bit (in I2C Master mode only)
SCK Release Control:
1 = Initiate Stop condition on SDA and SCL pins. Automatically cleared by hardware.
0 = Stop condition Idle
bit 1 RSEN: Repeated Start Condition Enabled bit (in I2C Master mode only)
1 = Initiate Repeated Start condition on SDA and SCL pins. Automatically cleared by hardware.
0 = Repeated Start condition Idle
bit 0 SEN: Start Condition Enabled bit (in I2C Master mode only)
In Master mode:
1 = Initiate Start condition on SDA and SCL pins. Automatically cleared by hardware.
0 = Start condition Idle
In Slave mode:
1 = Clock stretching is enabled for both slave transmit and slave receive (stretch enabled)
0 = Clock stretching is disabled
Note 1: For bits ACKEN, RCEN, PEN, RSEN, SEN: If the I2C module is not in the Idle mode, this bit may not be
set (no spooling) and the SSP1BUF may not be written (or writes to the SSP1BUF are disabled).
2010 Microchip Technology Inc. Preliminary DS41413A-page 277
PIC12F/LF1822/16F/LF1823
REGISTER 24-4: SSP1CON3: SSP1 CONTROL REGISTER 3
R-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 ACKTIM: Acknowledge Time Status bit (I2C mode only)(3)
1 = Indicates the I2C bus is in an Acknowledge sequence, set on 8TH falling edge of SCL clock
0 = Not an Acknowledge sequence, cleared on 9TH rising edge of SCL clock
bit 6 PCIE: Stop Condition Interrupt Enable bit (I2C mode only)
1 = Enable interrupt on detection of Stop condition
0 = Stop detection interrupts are disabled(2)
bit 5 SCIE: Start Condition Interrupt Enable bit (I2C mode only)
1 = Enable interrupt on detection of Start or Restart conditions
0 = Start detection interrupts are disabled(2)
bit 4 BOEN: Buffer Overwrite Enable bit
In SPI Slave mode:(1)
1 = SSP1BUF updates every time that a new data byte is shifted in ignoring the BF bit
0 = If new byte is received with BF bit of the SSP1STAT register already set, SSP1OV bit of the
SSP1CON1 register is set, and the buffer is not updated
In I2C Master mode and SPI Master mode:
This bit is ignored.
In I2C Slave mode:
1 = SSP1BUF is updated and ACK is generated for a received address/data byte, ignoring the
state of the SSP1OV bit only if the BF bit = 0.
0 = SSP1BUF is only updated when SSP1OV is clear
bit 3 SDAHT: SDA Hold Time Selection bit (I2C mode only)
1 = Minimum of 300 ns hold time on SDA after the falling edge of SCL
0 = Minimum of 100 ns hold time on SDA after the falling edge of SCL
bit 2 SBCDE: Slave Mode Bus Collision Detect Enable bit (I2C Slave mode only)
If on the rising edge of SCL, SDA is sampled low when the module is outputting a high state, the
BCL1IF bit of the PIR2 register is set, and bus goes idle
1 = Enable slave bus collision interrupts
0 = Slave bus collision interrupts are disabled
bit 1 AHEN: Address Hold Enable bit (I2C Slave mode only)
1 = Following the 8th falling edge of SCL for a matching received address byte; CKP bit of the
SSP1CON1 register will be cleared and the SCL will be held low.
0 = Address holding is disabled
bit 0 DHEN: Data Hold Enable bit (I2C Slave mode only)
1 = Following the 8th falling edge of SCL for a received data byte; slave hardware clears the CKP bit
of the SSP1CON1 register and SCL is held low.
0 = Data holding is disabled
Note 1: For daisy-chained SPI operation; allows the user to ignore all but the last received byte. SSP1OV is still set
when a new byte is received and BF = 1, but hardware continues to write the most recent byte to
SSP1BUF.
2: This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as enabled.
3: The ACKTIM Status bit is only active when the AHEN bit or DHEN bit is set.
PIC12F/LF1822/16F/LF1823
DS41413A-page 278 Preliminary 2010 Microchip Technology Inc.
REGISTER 24-5: SSP1MSK: SSP1 MASK REGISTER
R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1
MSK<7:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-1 MSK<7:1>: Mask bits
1 = The received address bit n is compared to SSP1ADD<n> to detect I2C address match
0 = The received address bit n is not used to detect I2C address match
bit 0 MSK<0>: Mask bit for I2C Slave mode, 10-bit Address
I2C Slave mode, 10-bit address (SSP1M<3:0> = 0111 or 1111):
1 = The received address bit 0 is compared to SSP1ADD<0> to detect I2C address match
0 = The received address bit 0 is not used to detect I2C address match
I2C Slave mode, 7-bit address, the bit is ignored
REGISTER 24-6: SSP1ADD: MSSP1 ADDRESS AND BAUD RATE REGISTER (I2C MODE)
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0
ADD<7:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
Master mode:
bit 7-0 ADD<7:0>: Baud Rate Clock Divider bits
SCL pin clock period = ((ADD<7:0> + 1) *4)/FOSC
10-Bit Slave mode — Most Significant Address byte:
bit 7-3 Not used: Unused for Most Significant Address byte. Bit state of this register is a “don’t care”. Bit pat-
tern sent by master is fixed by I2C specification and must be equal to ‘11110’. However, those bits are
compared by hardware and are not affected by the value in this register.
bit 2-1 ADD<2:1>: Two Most Significant bits of 10-bit address
bit 0 Not used: Unused in this mode. Bit state is a “don’t care”.
10-Bit Slave mode — Least Significant Address byte:
bit 7-0 ADD<7:0>: Eight Least Significant bits of 10-bit address
7-Bit Slave mode:
bit 7-1 ADD<7:1>: 7-bit address
bit 0 Not used: Unused in this mode. Bit state is a “don’t care”.
2010 Microchip Technology Inc. Preliminary DS41413A-page 279
PIC12F/LF1822/16F/LF1823
25.0 ENHANCED UNIVERSAL
SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) module is a serial I/O
communications peripheral. It contains all the clock
generators, shift registers and data buffers necessary
to perform an input or output serial data transfer
independent of device program execution. The
EUSART, also known as a Serial Communications
Interface (SCI), can be configured as a full-duplex
asynchronous system or half-duplex synchronous
system. Full-Duplex mode is useful for
communications with peripheral systems, such as CRT
terminals and personal computers. Half-Duplex
Synchronous mode is intended for communications
with peripheral devices, such as A/D or D/A integrated
circuits, serial EEPROMs or other microcontrollers.
These devices typically do not have internal clocks for
baud rate generation and require the external clock
signal provided by a master synchronous device.
The EUSART module includes the following capabilities:
• Full-duplex asynchronous transmit and receive
• Two-character input buffer
• One-character output buffer
• Programmable 8-bit or 9-bit character length
• Address detection in 9-bit mode
• Input buffer overrun error detection
• Received character framing error detection
• Half-duplex synchronous master
• Half-duplex synchronous slave
• Programmable clock polarity in synchronous
modes
• Sleep operation
The EUSART module implements the following
additional features, making it ideally suited for use in
Local Interconnect Network (LIN) bus systems:
• Automatic detection and calibration of the baud rate
• Wake-up on Break reception
• 13-bit Break character transmit
Block diagrams of the EUSART transmitter and
receiver are shown in Figure 25-1 and Figure 25-2.
FIGURE 25-1: EUSART TRANSMIT BLOCK DIAGRAM
TXIF
TXIE
Interrupt
TXEN
TX9D
MSb LSb
Data Bus
TXREG Register
Transmit Shift Register (TSR)
(8) 0
TX9
TRMT SPEN
TX/CK pin
Pin Buffer
and Control
8
SPBRGL
SPBRGH
BRG16
FOSC ÷ n
n
+ 1 Multiplier x4 x16 x64
SYNC 1X00 0
BRGH X110 0
BRG16 X101 0
Baud Rate Generator
•••
PIC12F/LF1822/16F/LF1823
DS41413A-page 280 Preliminary 2010 Microchip Technology Inc.
FIGURE 25-2: EUSART RECEIVE BLOCK DIAGRAM
The operation of the EUSART module is controlled
through three registers:
• Transmit Status and Control (TXSTA)
• Receive Status and Control (RCSTA)
• Baud Rate Control (BAUDCON)
These registers are detailed in Register 25-1,
Register 25-2 and Register 25-3, respectively.
When the receiver or transmitter section is not enabled
then the corresponding RX or TX pin may be used for
general purpose input and output.
RX/DT pin
Pin Buffer
and Control
SPEN
Data
Recovery
CREN OERR
FERR
RSR Register
MSb LSb
RX9D RCREG Register FIFO
Interrupt
RCIF
RCIE
Data Bus
8
Stop START
(8) 7 1 0
RX9
• • •
SPBRGLSPBRGH
BRG16
RCIDL
FOSC ÷ n
n
+ 1 Multiplier x4 x16 x64
SYNC 1X00 0
BRGH X110 0
BRG16 X101 0
Baud Rate Generator
2010 Microchip Technology Inc. Preliminary DS41413A-page 281
PIC12F/LF1822/16F/LF1823
25.1 EUSART Asynchronous Mode
The EUSART transmits and receives data using the
standard non-return-to-zero (NRZ) format. NRZ is
implemented with two levels: a VOH mark state which
represents a ‘1’ data bit, and a VOL space state which
represents a ‘0’ data bit. NRZ refers to the fact that
consecutively transmitted data bits of the same value
stay at the output level of that bit without returning to a
neutral level between each bit transmission. An NRZ
transmission port idles in the mark state. Each character
transmission consists of one Start bit followed by eight
or nine data bits and is always terminated by one or
more Stop bits. The Start bit is always a space and the
Stop bits are always marks. The most common data
format is 8 bits. Each transmitted bit persists for a period
of 1/(Baud Rate). An on-chip dedicated 8-bit/16-bit Baud
Rate Generator is used to derive standard baud rate
frequencies from the system oscillator. See Table 25-5
for examples of baud rate configurations.
The EUSART transmits and receives the LSb first. The
EUSART’s transmitter and receiver are functionally
independent, but share the same data format and baud
rate. Parity is not supported by the hardware, but can
be implemented in software and stored as the ninth
data bit.
25.1.1 EUSART ASYNCHRONOUS
TRANSMITTER
The EUSART transmitter block diagram is shown in
Figure 25-1. The heart of the transmitter is the serial
Transmit Shift Register (TSR), which is not directly
accessible by software. The TSR obtains its data from
the transmit buffer, which is the TXREG register.
25.1.1.1 Enabling the Transmitter
The EUSART transmitter is enabled for asynchronous
operations by configuring the following three control
bits:
•TXEN = 1
• SYNC = 0
• SPEN = 1
All other EUSART control bits are assumed to be in
their default state.
Setting the TXEN bit of the TXSTA register enables the
transmitter circuitry of the EUSART. Clearing the SYNC
bit of the TXSTA register configures the EUSART for
asynchronous operation. Setting the SPEN bit of the
RCSTA register enables the EUSART. The programmer
must set the corresponding TRIS bit to configure the
TX/CK I/O pin as an output.
25.1.1.2 Transmitting Data
A transmission is initiated by writing a character to the
TXREG register. If this is the first character, or the
previous character has been completely flushed from
the TSR, the data in the TXREG is immediately
transferred to the TSR register. If the TSR still contains
all or part of a previous character, the new character
data is held in the TXREG until the Stop bit of the
previous character has been transmitted. The pending
character in the TXREG is then transferred to the TSR
in one TCY immediately following the Stop bit
transmission. The transmission of the Start bit, data bits
and Stop bit sequence commences immediately
following the transfer of the data to the TSR from the
TXREG.
25.1.1.3 Transmit Interrupt Flag
The TXIF interrupt flag bit of the PIR1 register is set
whenever the EUSART transmitter is enabled and no
character is being held for transmission in the TXREG.
In other words, the TXIF bit is only clear when the TSR
is busy with a character and a new character has been
queued for transmission in the TXREG. The TXIF flag bit
is not cleared immediately upon writing TXREG. TXIF
becomes valid in the second instruction cycle following
the write execution. Polling TXIF immediately following
the TXREG write will return invalid results. The TXIF bit
is read-only, it cannot be set or cleared by software.
The TXIF interrupt can be enabled by setting the TXIE
interrupt enable bit of the PIE1 register. However, the
TXIF flag bit will be set whenever the TXREG is empty,
regardless of the state of TXIE enable bit.
To use interrupts when transmitting data, set the TXIE
bit only when there is more data to send. Clear the
TXIE interrupt enable bit upon writing the last character
of the transmission to the TXREG.
Note 1: The TXIF Transmitter Interrupt flag is set
when the TXEN enable bit is set.
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DS41413A-page 282 Preliminary 2010 Microchip Technology Inc.
25.1.1.4 TSR Status
The TRMT bit of the TXSTA register indicates the
status of the TSR register. This is a read-only bit. The
TRMT bit is set when the TSR register is empty and is
cleared when a character is transferred to the TSR
register from the TXREG. The TRMT bit remains clear
until all bits have been shifted out of the TSR register.
No interrupt logic is tied to this bit, so the user has to
poll this bit to determine the TSR status.
25.1.1.5 Transmitting 9-Bit Characters
The EUSART supports 9-bit character transmissions.
When the TX9 bit of the TXSTA register is set, the
EUSART will shift 9 bits out for each character transmit-
ted. The TX9D bit of the TXSTA register is the ninth,
and Most Significant, data bit. When transmitting 9-bit
data, the TX9D data bit must be written before writing
the 8 Least Significant bits into the TXREG. All nine bits
of data will be transferred to the TSR shift register
immediately after the TXREG is written.
A special 9-bit Address mode is available for use with
multiple receivers. See Section 25.1.2.7 “Address
Detection” for more information on the address mode.
25.1.1.6 Asynchronous Transmission Set-up:
1. Initialize the SPBRGH, SPBRGL register pair and
the BRGH and BRG16 bits to achieve the desired
baud rate (see Section 25.3 “EUSART Baud
Rate Generator (BRG)”).
2. Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
3. If 9-bit transmission is desired, set the TX9 con-
trol bit. A set ninth data bit will indicate that the 8
Least Significant data bits are an address when
the receiver is set for address detection.
4. Enable the transmission by setting the TXEN
control bit. This will cause the TXIF interrupt bit
to be set.
5. If interrupts are desired, set the TXIE interrupt
enable bit of the PIE1 register. An interrupt will
occur immediately provided that the GIE and
PEIE bits of the INTCON register are also set.
6. If 9-bit transmission is selected, the ninth bit
should be loaded into the TX9D data bit.
7. Load 8-bit data into the TXREG register. This
will start the transmission.
FIGURE 25-3: ASYNCHRONOUS TRANSMISSION
FIGURE 25-4: ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK)
Note: The TSR register is not mapped in data
memory, so it is not available to the user.
Word 1
Stop bit
Word 1
Transmit Shift Reg.
Start bit bit 0 bit 1 bit 7/8
Write to TXREG
Word 1
BRG Output
(Shift Clock)
TX/CK
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
1 TCY
pin
Transmit Shift Reg.
Write to TXREG
BRG Output
(Shift Clock)
TX/CK
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Word 1 Word 2
Word 1 Word 2
Start bit Stop bit Start bit
Transmit Shift Reg.
Word 1 Word 2
bit 0 bit 1 bit 7/8 bit 0
Note: This timing diagram shows two consecutive transmissions.
1 TCY
1 TCY
pin
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
2010 Microchip Technology Inc. Preliminary DS41413A-page 283
PIC12F/LF1822/16F/LF1823
TABLE 25-1: SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL — SCKP BRG16 —WUE ABDEN 290
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
SPBRGL BRG7 BRG6 BRG5 BRG4 BRG3 BRG2 BRG1 BRG0 291*
SPBRGH BRG15 BRG14 BRG13 BRG12 BRG11 BRG10 BRG9 BRG8 291*
TRISA —— TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
TXREG EUSART Transmit Data Register 281*
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Asynchronous Transmission.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 284 Preliminary 2010 Microchip Technology Inc.
25.1.2 EUSART ASYNCHRONOUS
RECEIVER
The Asynchronous mode is typically used in RS-232
systems. The receiver block diagram is shown in
Figure 25-2. The data is received on the RX/DT pin and
drives the data recovery block. The data recovery block
is actually a high-speed shifter operating at 16 times
the baud rate, whereas the serial Receive Shift
Register (RSR) operates at the bit rate. When all 8 or 9
bits of the character have been shifted in, they are
immediately transferred to a two character
First-In-First-Out (FIFO) memory. The FIFO buffering
allows reception of two complete characters and the
start of a third character before software must start
servicing the EUSART receiver. The FIFO and RSR
registers are not directly accessible by software.
Access to the received data is via the RCREG register.
25.1.2.1 Enabling the Receiver
The EUSART receiver is enabled for asynchronous
operation by configuring the following three control bits:
• CREN = 1
• SYNC = 0
• SPEN = 1
All other EUSART control bits are assumed to be in
their default state.
Setting the CREN bit of the RCSTA register enables the
receiver circuitry of the EUSART. Clearing the SYNC bit
of the TXSTA register configures the EUSART for
asynchronous operation. Setting the SPEN bit of the
RCSTA register enables the EUSART. The programmer
must set the corresponding TRIS bit to configure the
TX/CK I/O pin as an input.
25.1.2.2 Receiving Data
The receiver data recovery circuit initiates character
reception on the falling edge of the first bit. The first bit,
also known as the Start bit, is always a zero. The data
recovery circuit counts one-half bit time to the center of
the Start bit and verifies that the bit is still a zero. If it is
not a zero then the data recovery circuit aborts
character reception, without generating an error, and
resumes looking for the falling edge of the Start bit. If
the Start bit zero verification succeeds then the data
recovery circuit counts a full bit time to the center of the
next bit. The bit is then sampled by a majority detect
circuit and the resulting ‘0’ or ‘1’ is shifted into the RSR.
This repeats until all data bits have been sampled and
shifted into the RSR. One final bit time is measured and
the level sampled. This is the Stop bit, which is always
a ‘1’. If the data recovery circuit samples a ‘0’ in the
Stop bit position then a framing error is set for this
character, otherwise the framing error is cleared for this
character. See Section 25.1.2.4 “Receive Framing
Error” for more information on framing errors.
Immediately after all data bits and the Stop bit have
been received, the character in the RSR is transferred
to the EUSART receive FIFO and the RCIF interrupt
flag bit of the PIR1 register is set. The top character in
the FIFO is transferred out of the FIFO by reading the
RCREG register.
25.1.2.3 Receive Interrupts
The RCIF interrupt flag bit of the PIR1 register is set
whenever the EUSART receiver is enabled and there is
an unread character in the receive FIFO. The RCIF
interrupt flag bit is read-only, it cannot be set or cleared
by software.
RCIF interrupts are enabled by setting all of the
following bits:
• RCIE interrupt enable bit of the PIE1 register
• PEIE peripheral interrupt enable bit of the
INTCON register
• GIE global interrupt enable bit of the INTCON
register
The RCIF interrupt flag bit will be set when there is an
unread character in the FIFO, regardless of the state of
interrupt enable bits.
Note 1: If the RX/DT function is on an analog pin,
the corresponding ANSEL bit must be
cleared for the receiver to function.
Note: If the receive FIFO is overrun, no additional
characters will be received until the overrun
condition is cleared. See Section 25.1.2.5
“Receive Overrun Error” for more
information on overrun errors.
2010 Microchip Technology Inc. Preliminary DS41413A-page 285
PIC12F/LF1822/16F/LF1823
25.1.2.4 Receive Framing Error
Each character in the receive FIFO buffer has a
corresponding framing error Status bit. A framing error
indicates that a Stop bit was not seen at the expected
time. The framing error status is accessed via the
FERR bit of the RCSTA register. The FERR bit
represents the status of the top unread character in the
receive FIFO. Therefore, the FERR bit must be read
before reading the RCREG.
The FERR bit is read-only and only applies to the top
unread character in the receive FIFO. A framing error
(FERR = 1) does not preclude reception of additional
characters. It is not necessary to clear the FERR bit.
Reading the next character from the FIFO buffer will
advance the FIFO to the next character and the next
corresponding framing error.
The FERR bit can be forced clear by clearing the SPEN
bit of the RCSTA register which resets the EUSART.
Clearing the CREN bit of the RCSTA register does not
affect the FERR bit. A framing error by itself does not
generate an interrupt.
25.1.2.5 Receive Overrun Error
The receive FIFO buffer can hold two characters. An
overrun error will be generated if a third character, in its
entirety, is received before the FIFO is accessed. When
this happens the OERR bit of the RCSTA register is set.
The characters already in the FIFO buffer can be read
but no additional characters will be received until the
error is cleared. The error must be cleared by either
clearing the CREN bit of the RCSTA register or by
resetting the EUSART by clearing the SPEN bit of the
RCSTA register.
25.1.2.6 Receiving 9-bit Characters
The EUSART supports 9-bit character reception. When
the RX9 bit of the RCSTA register is set, the EUSART
will shift 9 bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth and Most Significant data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the 8 Least Significant bits from
the RCREG.
25.1.2.7 Address Detection
A special Address Detection mode is available for use
when multiple receivers share the same transmission
line, such as in RS-485 systems. Address detection is
enabled by setting the ADDEN bit of the RCSTA
register.
Address detection requires 9-bit character reception.
When address detection is enabled, only characters
with the ninth data bit set will be transferred to the
receive FIFO buffer, thereby setting the RCIF interrupt
bit. All other characters will be ignored.
Upon receiving an address character, user software
determines if the address matches its own. Upon
address match, user software must disable address
detection by clearing the ADDEN bit before the next
Stop bit occurs. When user software detects the end of
the message, determined by the message protocol
used, software places the receiver back into the
Address Detection mode by setting the ADDEN bit.
Note: If all receive characters in the receive
FIFO have framing errors, repeated reads
of the RCREG will not clear the FERR bit.
PIC12F/LF1822/16F/LF1823
DS41413A-page 286 Preliminary 2010 Microchip Technology Inc.
25.1.2.8 Asynchronous Reception Set-up:
1. Initialize the SPBRGH, SPBRGL register pair
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 25.3 “EUSART
Baud Rate Generator (BRG)”).
2. Clear the ANSEL bit for the RX pin (if applicable).
3. Enable the serial port by setting the SPEN bit.
The SYNC bit must be clear for asynchronous
operation.
4. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
5. If 9-bit reception is desired, set the RX9 bit.
6. Enable reception by setting the CREN bit.
7. The RCIF interrupt flag bit will be set when a
character is transferred from the RSR to the
receive buffer. An interrupt will be generated if
the RCIE interrupt enable bit was also set.
8. Read the RCSTA register to get the error flags
and, if 9-bit data reception is enabled, the ninth
data bit.
9. Get the received 8 Least Significant data bits
from the receive buffer by reading the RCREG
register.
10. If an overrun occurred, clear the OERR flag by
clearing the CREN receiver enable bit.
25.1.2.9 9-bit Address Detection Mode Set-up
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1. Initialize the SPBRGH, SPBRGL register pair
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 25.3 “EUSART
Baud Rate Generator (BRG)”).
2. Clear the ANSEL bit for the RX pin (if applicable).
3. Enable the serial port by setting the SPEN bit.
The SYNC bit must be clear for asynchronous
operation.
4. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
5. Enable 9-bit reception by setting the RX9 bit.
6. Enable address detection by setting the ADDEN
bit.
7. Enable reception by setting the CREN bit.
8. The RCIF interrupt flag bit will be set when a
character with the ninth bit set is transferred
from the RSR to the receive buffer. An interrupt
will be generated if the RCIE interrupt enable bit
was also set.
9. Read the RCSTA register to get the error flags.
The ninth data bit will always be set.
10. Get the received 8 Least Significant data bits
from the receive buffer by reading the RCREG
register. Software determines if this is the
device’s address.
11. If an overrun occurred, clear the OERR flag by
clearing the CREN receiver enable bit.
12. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and generate interrupts.
FIGURE 25-5: ASYNCHRONOUS RECEPTION
Start
bit bit 7/8
bit 1bit 0 bit 7/8 bit 0Stop
bit
Start
bit
Start
bit
bit 7/8 Stop
bit
RX/DT pin
Reg
Rcv Buffer Reg.
Rcv Shift
Read Rcv
Buffer Reg.
RCREG
RCIF
(Interrupt Flag)
OERR bit
CREN
Word 1
RCREG
Word 2
RCREG
Stop
bit
Note: This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word,
causing the OERR (overrun) bit to be set.
RCIDL
2010 Microchip Technology Inc. Preliminary DS41413A-page 287
PIC12F/LF1822/16F/LF1823
TABLE 25-2: SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL —SCKP BRG16 —WUEABDEN 290
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
RCREG EUSART Receive Data Register 284*
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
SPBRGL BRG7 BRG6 BRG5 BRG4 BRG3 BRG2 BRG1 BRG0 291*
SPBRGH BRG15 BRG14 BRG13 BRG12 BRG11 BRG10 BRG9 BRG8 291*
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) ——TRISC5TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Asynchronous Reception.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 288 Preliminary 2010 Microchip Technology Inc.
25.2 Clock Accuracy with
Asynchronous Operation
The factory calibrates the internal oscillator block out-
put (INTOSC). However, the INTOSC frequency may
drift as VDD or temperature changes, and this directly
affects the asynchronous baud rate. Two methods may
be used to adjust the baud rate clock, but both require
a reference clock source of some kind.
The first (preferred) method uses the OSCTUNE
register to adjust the INTOSC output. Adjusting the
value in the OSCTUNE register allows for fine resolution
changes to the system clock source. See Section 5.2.2
“Internal Clock Sources” for more information.
The other method adjusts the value in the Baud Rate
Generator. This can be done automatically with the
Auto-Baud Detect feature (see Section 25.3.1
“Auto-Baud Detect”). There may not be fine enough
resolution when adjusting the Baud Rate Generator to
compensate for a gradual change in the peripheral
clock frequency.
REGISTER 25-1: TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R-1/1 R/W-0/0
CSRC TX9 TXEN(1) SYNC SENDB BRGH TRMT TX9D
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6 TX9: 9-bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5 TXEN: Transmit Enable bit(1)
1 = Transmit enabled
0 = Transmit disabled
bit 4 SYNC: EUSART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3 SENDB: Send Break Character bit
Asynchronous mode:
1 = Send Sync Break on next transmission (cleared by hardware upon completion)
0 = Sync Break transmission completed
Synchronous mode:
Don’t care
bit 2 BRGH: High Baud Rate Select bit
Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode
bit 1 TRMT: Transmit Shift Register Status bit
1 = TSR empty
0 = TSR full
bit 0 TX9D: Ninth bit of Transmit Data
Can be address/data bit or a parity bit.
Note 1: SREN/CREN overrides TXEN in Sync mode.
2010 Microchip Technology Inc. Preliminary DS41413A-page 289
PIC12F/LF1822/16F/LF1823
REGISTER 25-2: RCSTA: RECEIVE STATUS AND CONTROL REGISTER(1)
R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R-0/0 R-0/0 R-x/x
SPEN RX9 SREN CREN ADDEN FERR OERR RX9D
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 SPEN: Serial Port Enable bit
1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins)
0 = Serial port disabled (held in Reset)
bit 6 RX9: 9-bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5 SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care
Synchronous mode – Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode – Slave
Don’t care
bit 4 CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3 ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, enable interrupt and load the receive buffer when RSR<8> is set
0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 8-bit (RX9 = 0):
Don’t care
bit 2 FERR: Framing Error bit
1 = Framing error (can be updated by reading RCREG register and receive next valid byte)
0 = No framing error
bit 1 OERR: Overrun Error bit
1 = Overrun error (can be cleared by clearing bit CREN)
0 = No overrun error
bit 0 RX9D: Ninth bit of Received Data
This can be address/data bit or a parity bit and must be calculated by user firmware.
PIC12F/LF1822/16F/LF1823
DS41413A-page 290 Preliminary 2010 Microchip Technology Inc.
REGISTER 25-3: BAUDCON: BAUD RATE CONTROL REGISTER
R-0/0 R-1/1 U-0 R/W-0/0 R/W-0/0 U-0 R/W-0/0 R/W-0/0
ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 ABDOVF: Auto-Baud Detect Overflow bit
Asynchronous mode:
1 = Auto-baud timer overflowed
0 = Auto-baud timer did not overflow
Synchronous mode:
Don’t care
bit 6 RCIDL: Receive Idle Flag bit
Asynchronous mode:
1 = Receiver is Idle
0 = Start bit has been received and the receiver is receiving
Synchronous mode:
Don’t care
bit 5 Unimplemented: Read as ‘0’
bit 4 SCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
1 = Transmit inverted data
0 = Transmit non-inverted data
Synchronous mode:
1 = Data is clocked on rising edge of the clock
0 = Data is clocked on falling edge of the clock
bit 3 BRG16: 16-bit Baud Rate Generator bit
1 = 16-bit Baud Rate Generator is used
0 = 8-bit Baud Rate Generator is used
bit 2 Unimplemented: Read as ‘0’
bit 1 WUE: Wake-up Enable bit
Asynchronous mode:
1 = Receiver is waiting for a falling edge. No character will be received, byte RCIF will be set. WUE
will automatically clear after RCIF is set.
0 = Receiver is operating normally
Synchronous mode:
Don’t care
bit 0 ABDEN: Auto-Baud Detect Enable bit
Asynchronous mode:
1 = Auto-Baud Detect mode is enabled (clears when auto-baud is complete)
0 = Auto-Baud Detect mode is disabled
Synchronous mode:
Don’t care
2010 Microchip Technology Inc. Preliminary DS41413A-page 291
PIC12F/LF1822/16F/LF1823
25.3 EUSART Baud Rate Generator
(BRG)
The Baud Rate Generator (BRG) is an 8-bit or 16-bit
timer that is dedicated to the support of both the
asynchronous and synchronous EUSART operation.
By default, the BRG operates in 8-bit mode. Setting the
BRG16 bit of the BAUDCON register selects 16-bit
mode.
The SPBRGH, SPBRGL register pair determines the
period of the free running baud rate timer. In
Asynchronous mode the multiplier of the baud rate
period is determined by both the BRGH bit of the TXSTA
register and the BRG16 bit of the BAUDCON register. In
Synchronous mode, the BRGH bit is ignored.
Table 25-3 contains the formulas for determining the
baud rate. Example 25-1 provides a sample calculation
for determining the baud rate and baud rate error.
Typical baud rates and error values for various
asynchronous modes have been computed for your
convenience and are shown in Table 25-3. It may be
advantageous to use the high baud rate (BRGH = 1),
or the 16-bit BRG (BRG16 = 1) to reduce the baud rate
error. The 16-bit BRG mode is used to achieve slow
baud rates for fast oscillator frequencies.
Writing a new value to the SPBRGH, SPBRGL register
pair causes the BRG timer to be reset (or cleared). This
ensures that the BRG does not wait for a timer overflow
before outputting the new baud rate.
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit to
make sure that the receive operation is Idle before
changing the system clock.
EXAMPLE 25-1: CALCULATING BAUD
RATE ERROR
For a device with FOSC of 16 MHz, desired baud rate
of 9600, Asynchronous mode, 8-bit BRG:
Solving for SPBRGH:SPBRGL:
X
FOSC
Desired Baud Rate
---------------------------------------------
64
--------------------------------------------- 1–=
Desired Baud Rate FOSC
64 [SPBRGH:SPBRGL] 1+
------------------------------------------------------------------------=
16000000
9600
------------------------
64
------------------------1–=
25.04225==
Calculated Baud Rate 16000000
64 25 1+
---------------------------=
9615=
Error Calc. Baud Rate Desired Baud Rate –
Desired Baud Rate
--------------------------------------------------------------------------------------------=
9615 9600–
9600
---------------------------------- 0 . 1 6 %==
PIC12F/LF1822/16F/LF1823
DS41413A-page 292 Preliminary 2010 Microchip Technology Inc.
TABLE 25-3: BAUD RATE FORMULAS
TABLE 25-4: SUMMARY OF REGISTERS ASSOCIATED WITH THE BAUD RATE GENERATOR
Configuration Bits
BRG/EUSART Mode Baud Rate Formula
SYNC BRG16 BRGH
000 8-bit/Asynchronous FOSC/[64 (n+1)]
001 8-bit/Asynchronous FOSC/[16 (n+1)]
010 16-bit/Asynchronous
011 16-bit/Asynchronous
FOSC/[4 (n+1)]10x 8-bit/Synchronous
11x 16-bit/Synchronous
Legend: x = Don’t care, n = value of SPBRGH, SPBRGL register pair
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL —SCKP BRG16 —WUE ABDEN 290
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
SPBRGL BRG7 BRG6 BRG5 BRG4 BRG3 BRG2 BRG1 BRG0 291*
SPBRGH BRG15 BRG14 BRG13 BRG12 BRG11 BRG10 BRG9 BRG8 291*
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for the Baud Rate Generator.
* Page provides register information.
2010 Microchip Technology Inc. Preliminary DS41413A-page 293
PIC12F/LF1822/16F/LF1823
TABLE 25-5: BAUD RATES FOR ASYNCHRONOUS MODES
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 0
FOSC = 32.000 MHz FOSC = 20.000 MHz FOSC = 18.432 MHz FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300—— — —— — —— — —— —
1200 — — — 1221 1.73 255 1200 0.00 239 1200 0.00 143
2400 2404 0.16 207 2404 0.16 129 2400 0.00 119 2400 0.00 71
9600 9615 0.16 51 9470 -1.36 32 9600 0.00 29 9600 0.00 17
10417 10417 0.00 47 10417 0.00 29 10286 -1.26 27 10165 -2.42 16
19.2k 19.23k 0.16 25 19.53k 1.73 15 19.20k 0.00 14 19.20k 0.00 8
57.6k 55.55k -3.55 3 — — — 57.60k 0.00 7 57.60k 0.00 2
115.2k — — — — — — — — — — — —
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 0
FOSC = 8.000 MHz FOSC = 4.000 MHz FOSC = 3.6864 MHz FOSC = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 — — — 300 0.16 207 300 0.00 191 300 0.16 51
1200 1202 0.16 103 1202 0.16 51 1200 0.00 47 1202 0.16 12
2400 2404 0.16 51 2404 0.16 25 2400 0.00 23 — — —
9600 9615 0.16 12 — — — 9600 0.00 5 — — —
10417 10417 0.00 11 10417 0.00 5 — — — — — —
19.2k — — — — — — 19.20k 0.00 2 — — —
57.6k — — — — — — 57.60k 0.00 0 — — —
115.2k — — — — — — — — — — — —
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 0
FOSC = 32.000 MHz FOSC = 20.000 MHz FOSC = 18.432 MHz FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 —— — —— — —— — —— —
1200 — — — — — — — — — — — —
2400 — — — — — — — — — —— —
9600 9615 0.16 207 9615 0.16 129 9600 0.00 119 9600 0.00 71
10417 10417 0.00 191 10417 0.00 119 10378 -0.37 110 10473 0.53 65
19.2k 19.23k 0.16 103 19.23k 0.16 64 19.20k 0.00 59 19.20k 0.00 35
57.6k 57.14k -0.79 34 56.82k -1.36 21 57.60k 0.00 19 57.60k 0.00 11
115.2k 117.64k 2.12 16 113.64k -1.36 10 115.2k 0.00 9 115.2k 0.00 5
PIC12F/LF1822/16F/LF1823
DS41413A-page 294 Preliminary 2010 Microchip Technology Inc.
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 0
FOSC = 8.000 MHz FOSC = 4.000 MHz FOSC = 3.6864 MHz FOSC = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 —— — — — — — — — 300 0.16 207
1200 — — — 1202 0.16 207 1200 0.00 191 1202 0.16 51
2400 2404 0.16 207 2404 0.16 103 2400 0.00 95 2404 0.16 25
9600 9615 0.16 51 9615 0.16 25 9600 0.00 23 — — —
10417 10417 0.00 47 10417 0.00 23 10473 0.53 21 10417 0.00 5
19.2k 19231 0.16 25 19.23k 0.16 12 19.2k 0.00 11 — — —
57.6k 55556 -3.55 8 — — — 57.60k 0.00 3 — — —
115.2k — — — — — — 115.2k 0.00 1 — — —
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 1
FOSC = 32.000 MHz FOSC = 20.000 MHz FOSC = 18.432 MHz FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300.0 0.00 6666 300.0 -0.01 4166 300.0 0.00 3839 300.0 0.00 2303
1200 1200 -0.02 3332 1200 -0.03 1041 1200 0.00 959 1200 0.00 575
2400 2401 -0.04 832 2399 -0.03 520 2400 0.00 479 2400 0.00 287
9600 9615 0.16 207 9615 0.16 129 9600 0.00 119 9600 0.00 71
10417 10417 0.00 191 10417 0.00 119 10378 -0.37 110 10473 0.53 65
19.2k 19.23k 0.16 103 19.23k 0.16 64 19.20k 0.00 59 19.20k 0.00 35
57.6k 57.14k -0.79 34 56.818 -1.36 21 57.60k 0.00 19 57.60k 0.00 11
115.2k 117.6k 2.12 16 113.636 -1.36 10 115.2k 0.00 9 115.2k 0.00 5
BAUD
RATE
SYNC = 0, BRGH = 0, BRG16 = 1
FOSC = 8.000 MHz FOSC = 4.000 MHz FOSC = 3.6864 MHz FOSC = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 299.9 -0.02 1666 300.1 0.04 832 300.0 0.00 767 300.5 0.16 207
1200 1199 -0.08 416 1202 0.16 207 1200 0.00 191 1202 0.16 51
2400 2404 0.16 207 2404 0.16 103 2400 0.00 95 2404 0.16 25
9600 9615 0.16 51 9615 0.16 25 9600 0.00 23 — — —
10417 10417 0.00 47 10417 0.00 23 10473 0.53 21 10417 0.00 5
19.2k 19.23k 0.16 25 19.23k 0.16 12 19.20k 0.00 11 — — —
57.6k 55556 -3.55 8 — — — 57.60k 0.00 3 — — —
115.2k — — — — — — 115.2k 0.00 1 — — —
TABLE 25-5: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
2010 Microchip Technology Inc. Preliminary DS41413A-page 295
PIC12F/LF1822/16F/LF1823
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
FOSC = 32.000 MHz FOSC = 20.000 MHz FOSC = 18.432 MHz FOSC = 11.0592 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300.0 0.00 26666 300.0 0.00 16665 300.0 0.00 15359 300.0 0.00 9215
1200 1200 0.00 6666 1200 -0.01 4166 1200 0.00 3839 1200 0.00 2303
2400 2400 0.01 3332 2400 0.02 2082 2400 0.00 1919 2400 0.00 1151
9600 9604 0.04 832 9597 -0.03 520 9600 0.00 479 9600 0.00 287
10417 10417 0.00 767 10417 0.00 479 10425 0.08 441 10433 0.16 264
19.2k 19.18k -0.08 416 19.23k 0.16 259 19.20k 0.00 239 19.20k 0.00 143
57.6k 57.55k -0.08 138 57.47k -0.22 86 57.60k 0.00 79 57.60k 0.00 47
115.2k 115.9k 0.64 68 116.3k 0.94 42 115.2k 0.00 39 115.2k 0.00 23
BAUD
RATE
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
FOSC = 8.000 MHz FOSC = 4.000 MHz FOSC = 3.6864 MHz FOSC = 1.000 MHz
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
Actual
Rate
%
Error
SPBRG
value
(decimal)
300 300.0 0.00 6666 300.0 0.01 3332 300.0 0.00 3071 300.1 0.04 832
1200 1200 -0.02 1666 1200 0.04 832 1200 0.00 767 1202 0.16 207
2400 2401 0.04 832 2398 0.08 416 2400 0.00 383 2404 0.16 103
9600 9615 0.16 207 9615 0.16 103 9600 0.00 95 9615 0.16 25
10417 10417 0 191 10417 0.00 95 10473 0.53 87 10417 0.00 23
19.2k 19.23k 0.16 103 19.23k 0.16 51 19.20k 0.00 47 19.23k 0.16 12
57.6k 57.14k -0.79 34 58.82k 2.12 16 57.60k 0.00 15 — — —
115.2k 117.6k 2.12 16 111.1k -3.55 8 115.2k 0.00 7 — — —
TABLE 25-5: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
PIC12F/LF1822/16F/LF1823
DS41413A-page 296 Preliminary 2010 Microchip Technology Inc.
25.3.1 AUTO-BAUD DETECT
The EUSART module supports automatic detection
and calibration of the baud rate.
In the Auto-Baud Detect (ABD) mode, the clock to the
BRG is reversed. Rather than the BRG clocking the
incoming RX signal, the RX signal is timing the BRG.
The Baud Rate Generator is used to time the period of
a received 55h (ASCII “U”) which is the Sync character
for the LIN bus. The unique feature of this character is
that it has five rising edges including the Stop bit edge.
Setting the ABDEN bit of the BAUDCON register starts
the auto-baud calibration sequence (Figure 25-6).
While the ABD sequence takes place, the EUSART
state machine is held in Idle. On the first rising edge of
the receive line, after the Start bit, the SPBRG begins
counting up using the BRG counter clock as shown in
Table 25-6. The fifth rising edge will occur on the RX pin
at the end of the eighth bit period. At that time, an
accumulated value totaling the proper BRG period is
left in the SPBRGH, SPBRGL register pair, the ABDEN
bit is automatically cleared and the RCIF interrupt flag
is set. The value in the RCREG needs to be read to
clear the RCIF interrupt. RCREG content should be
discarded. When calibrating for modes that do not use
the SPBRGH register the user can verify that the
SPBRGL register did not overflow by checking for 00h
in the SPBRGH register.
The BRG auto-baud clock is determined by the BRG16
and BRGH bits as shown in Table 25-6. During ABD,
both the SPBRGH and SPBRGL registers are used as
a 16-bit counter, independent of the BRG16 bit setting.
While calibrating the baud rate period, the SPBRGH
and SPBRGL registers are clocked at 1/8th the BRG
base clock rate. The resulting byte measurement is the
average bit time when clocked at full speed.
TABLE 25-6: BRG COUNTER CLOCK RATES
FIGURE 25-6: AUTOMATIC BAUD RATE CALIBRATION
Note 1: If the WUE bit is set with the ABDEN bit,
auto-baud detection will occur on the byte
following the Break character (see
Section 25.3.3 “Auto-Wake-up on
Break”).
2: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some combinations of oscillator frequency
and EUSART baud rates are not possible.
3: During the auto-baud process, the
auto-baud counter starts counting at 1.
Upon completion of the auto-baud
sequence, to achieve maximum accuracy,
subtract 1 from the SPBRGH:SPBRGL
register pair.
BRG16 BRGH BRG Base
Clock
BRG ABD
Clock
00FOSC/64 FOSC/512
01FOSC/16 FOSC/128
10FOSC/16 FOSC/128
11 FOSC/4 FOSC/32
Note: During the ABD sequence, SPBRGL and
SPBRGH registers are both used as a 16-bit
counter, independent of BRG16 setting.
BRG Value
RX pin
ABDEN bit
RCIF bit
bit 0 bit 1
(Interrupt)
Read
RCREG
BRG Clock
Start
Auto Cleared
Set by User
XXXXh 0000h
Edge #1
bit 2 bit 3
Edge #2
bit 4 bit 5
Edge #3
bit 6 bit 7
Edge #4
Stop bit
Edge #5
001Ch
Note 1: The ABD sequence requires the EUSART module to be configured in Asynchronous mode.
SPBRGL XXh 1Ch
SPBRGH XXh 00h
RCIDL
2010 Microchip Technology Inc. Preliminary DS41413A-page 297
PIC12F/LF1822/16F/LF1823
25.3.2 AUTO-BAUD OVERFLOW
During the course of automatic baud detection, the
ABDOVF bit of the BAUDCON register will be set if the
baud rate counter overflows before the fifth rising edge
is detected on the RX pin. The ABDOVF bit indicates
that the counter has exceeded the maximum count that
can fit in the 16 bits of the SPBRGH:SPBRGL register
pair. After the ABDOVF has been set, the counter con-
tinues to count until the fifth rising edge is detected on
the RX pin. Upon detecting the fifth RX edge, the hard-
ware will set the RCIF interrupt flag and clear the
ABDEN bit of the BAUDCON register. The RCIF flag
can be subsequently cleared by reading the RCREG
register. The ABDOVF flag of the BAUDCON register
can be cleared by software directly.
To terminate the auto-baud process before the RCIF
flag is set, clear the ABDEN bit then clear the ABDOVF
bit of the BAUDCON register. The ABDOVF bit will
remain set if the ABDEN bit is not cleared first.
25.3.3 AUTO-WAKE-UP ON BREAK
During Sleep mode, all clocks to the EUSART are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper character reception cannot be
performed. The Auto-Wake-up feature allows the
controller to wake-up due to activity on the RX/DT line.
This feature is available only in Asynchronous mode.
The Auto-Wake-up feature is enabled by setting the
WUE bit of the BAUDCON register. Once set, the normal
receive sequence on RX/DT is disabled, and the
EUSART remains in an Idle state, monitoring for a
wake-up event independent of the CPU mode. A
wake-up event consists of a high-to-low transition on the
RX/DT line. (This coincides with the start of a Sync Break
or a wake-up signal character for the LIN protocol.)
The EUSART module generates an RCIF interrupt
coincident with the wake-up event. The interrupt is
generated synchronously to the Q clocks in normal CPU
operating modes (Figure 25-7), and asynchronously if
the device is in Sleep mode (Figure 25-8). The interrupt
condition is cleared by reading the RCREG register.
The WUE bit is automatically cleared by the low-to-high
transition on the RX line at the end of the Break. This
signals to the user that the Break event is over. At this
point, the EUSART module is in Idle mode waiting to
receive the next character.
25.3.3.1 Special Considerations
Break Character
To avoid character errors or character fragments during
a wake-up event, the wake-up character must be all
zeros.
When the wake-up is enabled the function works
independent of the low time on the data stream. If the
WUE bit is set and a valid non-zero character is
received, the low time from the Start bit to the first rising
edge will be interpreted as the wake-up event. The
remaining bits in the character will be received as a
fragmented character and subsequent characters can
result in framing or overrun errors.
Therefore, the initial character in the transmission must
be all ‘0’s. This must be 10 or more bit times, 13-bit
times recommended for LIN bus, or any number of bit
times for standard RS-232 devices.
Oscillator Startup Time
Oscillator start-up time must be considered, especially
in applications using oscillators with longer start-up
intervals (i.e., LP, XT or HS/PLL mode). The Sync
Break (or wake-up signal) character must be of
sufficient length, and be followed by a sufficient
interval, to allow enough time for the selected oscillator
to start and provide proper initialization of the EUSART.
WUE Bit
The wake-up event causes a receive interrupt by
setting the RCIF bit. The WUE bit is cleared in
hardware by a rising edge on RX/DT. The interrupt
condition is then cleared in software by reading the
RCREG register and discarding its contents.
To ensure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process
before setting the WUE bit. If a receive operation is not
occurring, the WUE bit may then be set just prior to
entering the Sleep mode.
PIC12F/LF1822/16F/LF1823
DS41413A-page 298 Preliminary 2010 Microchip Technology Inc.
FIGURE 25-7: AUTO-WAKE-UP BIT (WUE) TIMING DURING NORMAL OPERATION
FIGURE 25-8: AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
WUE bit
RX/DT Line
RCIF
Bit set by user Auto Cleared
Cleared due to User Read of RCREG
Note 1: The EUSART remains in Idle while the WUE bit is set.
Q1Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4
OSC1
WUE bit
RX/DT Line
RCIF
Bit Set by User Auto Cleared
Cleared due to User Read of RCREG
Sleep Command Executed
Note 1
Note 1: If the wake-up event requires long oscillator warm-up time, the automatic clearing of the WUE bit can occur while the stposc signal is
still active. This sequence should not depend on the presence of Q clocks.
2: The EUSART remains in Idle while the WUE bit is set.
Sleep Ends
2010 Microchip Technology Inc. Preliminary DS41413A-page 299
PIC12F/LF1822/16F/LF1823
25.3.4 BREAK CHARACTER SEQUENCE
The EUSART module has the capability of sending the
special Break character sequences that are required by
the LIN bus standard. A Break character consists of a
Start bit, followed by 12 ‘0’ bits and a Stop bit.
To send a Break character, set the SENDB and TXEN
bits of the TXSTA register. The Break character trans-
mission is then initiated by a write to the TXREG. The
value of data written to TXREG will be ignored and all
‘0’s will be transmitted.
The SENDB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN specification).
The TRMT bit of the TXSTA register indicates when the
transmit operation is active or Idle, just as it does during
normal transmission. See Figure 25-9 for the timing of
the Break character sequence.
25.3.4.1 Break and Sync Transmit Sequence
The following sequence will start a message frame
header made up of a Break, followed by an auto-baud
Sync byte. This sequence is typical of a LIN bus
master.
1. Configure the EUSART for the desired mode.
2. Set the TXEN and SENDB bits to enable the
Break sequence.
3. Load the TXREG with a dummy character to
initiate transmission (the value is ignored).
4. Write ‘55h’ to TXREG to load the Sync character
into the transmit FIFO buffer.
5. After the Break has been sent, the SENDB bit is
reset by hardware and the Sync character is
then transmitted.
When the TXREG becomes empty, as indicated by the
TXIF, the next data byte can be written to TXREG.
25.3.5 RECEIVING A BREAK CHARACTER
The Enhanced EUSART module can receive a Break
character in two ways.
The first method to detect a Break character uses the
FERR bit of the RCSTA register and the Received data
as indicated by RCREG. The Baud Rate Generator is
assumed to have been initialized to the expected baud
rate.
A Break character has been received when;
• RCIF bit is set
• FERR bit is set
• RCREG = 00h
The second method uses the Auto-Wake-up feature
described in Section 25.3.3 “Auto-Wake-up on
Break”. By enabling this feature, the EUSART will
sample the next two transitions on RX/DT, cause an
RCIF interrupt, and receive the next data byte followed
by another interrupt.
Note that following a Break character, the user will
typically want to enable the Auto-Baud Detect feature.
For both methods, the user can set the ABDEN bit of
the BAUDCON register before placing the EUSART in
Sleep mode.
FIGURE 25-9: SEND BREAK CHARACTER SEQUENCE
Write to TXREG Dummy Write
BRG Output
(Shift Clock)
Start bit bit 0 bit 1 bit 11 Stop bit
Break
TXIF bit
(Transmit
Interrupt Flag)
TX (pin)
TRMT bit
(Transmit Shift
Empty Flag)
SENDB
(send Break
control bit)
SENDB Sampled Here Auto Cleared
PIC12F/LF1822/16F/LF1823
DS41413A-page 300 Preliminary 2010 Microchip Technology Inc.
25.4 EUSART Synchronous Mode
Synchronous serial communications are typically used
in systems with a single master and one or more
slaves. The master device contains the necessary cir-
cuitry for baud rate generation and supplies the clock
for all devices in the system. Slave devices can take
advantage of the master clock by eliminating the inter-
nal clock generation circuitry.
There are two signal lines in Synchronous mode: a bidi-
rectional data line and a clock line. Slaves use the
external clock supplied by the master to shift the serial
data into and out of their respective receive and trans-
mit shift registers. Since the data line is bidirectional,
synchronous operation is half-duplex only. Half-duplex
refers to the fact that master and slave devices can
receive and transmit data but not both simultaneously.
The EUSART can operate as either a master or slave
device.
Start and Stop bits are not used in synchronous trans-
missions.
25.4.1 SYNCHRONOUS MASTER MODE
The following bits are used to configure the EUSART
for Synchronous Master operation:
• SYNC = 1
• CSRC = 1
• SREN = 0 (for transmit); SREN = 1 (for receive)
• CREN = 0 (for transmit); CREN = 1 (for receive)
• SPEN = 1
Setting the SYNC bit of the TXSTA register configures
the device for synchronous operation. Setting the CSRC
bit of the TXSTA register configures the device as a
master. Clearing the SREN and CREN bits of the RCSTA
register ensures that the device is in the Transmit mode,
otherwise the device will be configured to receive. Setting
the SPEN bit of the RCSTA register enables the
EUSART.
25.4.1.1 Master Clock
Synchronous data transfers use a separate clock line,
which is synchronous with the data. A device config-
ured as a master transmits the clock on the TX/CK line.
The TX/CK pin output driver is automatically enabled
when the EUSART is configured for synchronous
transmit or receive operation. Serial data bits change
on the leading edge to ensure they are valid at the trail-
ing edge of each clock. One clock cycle is generated
for each data bit. Only as many clock cycles are gener-
ated as there are data bits.
25.4.1.2 Clock Polarity
A clock polarity option is provided for Microwire
compatibility. Clock polarity is selected with the SCKP
bit of the BAUDCON register. Setting the SCKP bit sets
the clock Idle state as high. When the SCKP bit is set,
the data changes on the falling edge of each clock.
Clearing the SCKP bit sets the Idle state as low. When
the SCKP bit is cleared, the data changes on the rising
edge of each clock.
25.4.1.3 Synchronous Master Transmission
Data is transferred out of the device on the RX/DT pin.
The RX/DT and TX/CK pin output drivers are automat-
ically enabled when the EUSART is configured for
synchronous master transmit operation.
A transmission is initiated by writing a character to the
TXREG register. If the TSR still contains all or part of a
previous character, the new character data is held in
the TXREG until the last bit of the previous character
has been transmitted. If this is the first character, or the
previous character has been completely flushed from
the TSR, the data in the TXREG is immediately trans-
ferred to the TSR. The transmission of the character
commences immediately following the transfer of the
data to the TSR from the TXREG.
Each data bit changes on the leading edge of the mas-
ter clock and remains valid until the subsequent leading
clock edge.
25.4.1.4 Synchronous Master Transmission
Set-up:
1. Initialize the SPBRGH, SPBRGL register pair
and the BRGH and BRG16 bits to achieve the
desired baud rate (see Section 25.3 “EUSART
Baud Rate Generator (BRG)”).
2. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
3. Disable Receive mode by clearing bits SREN
and CREN.
4. Enable Transmit mode by setting the TXEN bit.
5. If 9-bit transmission is desired, set the TX9 bit.
6. If interrupts are desired, set the TXIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
7. If 9-bit transmission is selected, the ninth bit
should be loaded in the TX9D bit.
8. Start transmission by loading data to the TXREG
register.
Note: The TSR register is not mapped in data
memory, so it is not available to the user.
2010 Microchip Technology Inc. Preliminary DS41413A-page 301
PIC12F/LF1822/16F/LF1823
FIGURE 25-10: SYNCHRONOUS TRANSMISSION
FIGURE 25-11: SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
TABLE 25-7: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER
TRANSMISSION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL — SCKP BRG16 —WUE ABDEN 290
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
SPBRGL BRG7 BRG6 BRG5 BRG4 BRG3 BRG2 BRG1 BRG0 291*
SPBRGH BRG15 BRG14 BRG13 BRG12 BRG11 BRG10 BRG9 BRG8 291*
TRISC(1) — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
TXREG EUSART Transmit Data Register 281*
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Master Transmission.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
bit 0 bit 1 bit 7
Word 1
bit 2 bit 0 bit 1 bit 7
RX/DT
Write to
TXREG Reg
TXIF bit
(Interrupt Flag)
TXEN bit ‘1’ ‘1’
Word 2
TRMT bit
Write Word 1 Write Word 2
Note: Sync Master mode, SPBRGL = 0, continuous transmission of two 8-bit words.
pin
TX/CK pin
TX/CK pin
(SCKP = 0)
(SCKP = 1)
RX/DT pin
TX/CK pin
Write to
TXREG reg
TXIF bit
TRMT bit
bit 0 bit 1 bit 2 bit 6 bit 7
TXEN bit
PIC12F/LF1822/16F/LF1823
DS41413A-page 302 Preliminary 2010 Microchip Technology Inc.
25.4.1.5 Synchronous Master Reception
Data is received at the RX/DT pin. The RX/DT pin
output driver is automatically disabled when the
EUSART is configured for synchronous master receive
operation.
In Synchronous mode, reception is enabled by setting
either the Single Receive Enable bit (SREN of the
RCSTA register) or the Continuous Receive Enable bit
(CREN of the RCSTA register).
When SREN is set and CREN is clear, only as many
clock cycles are generated as there are data bits in a
single character. The SREN bit is automatically cleared
at the completion of one character. When CREN is set,
clocks are continuously generated until CREN is
cleared. If CREN is cleared in the middle of a character
the CK clock stops immediately and the partial charac-
ter is discarded. If SREN and CREN are both set, then
SREN is cleared at the completion of the first character
and CREN takes precedence.
To initiate reception, set either SREN or CREN. Data is
sampled at the RX/DT pin on the trailing edge of the
TX/CK clock pin and is shifted into the Receive Shift
Register (RSR). When a complete character is
received into the RSR, the RCIF bit is set and the char-
acter is automatically transferred to the two character
receive FIFO. The Least Significant eight bits of the top
character in the receive FIFO are available in RCREG.
The RCIF bit remains set as long as there are unread
characters in the receive FIFO.
25.4.1.6 Slave Clock
Synchronous data transfers use a separate clock line,
which is synchronous with the data. A device configured
as a slave receives the clock on the TX/CK line. The
TX/CK pin output driver is automatically disabled when
the device is configured for synchronous slave transmit
or receive operation. Serial data bits change on the
leading edge to ensure they are valid at the trailing edge
of each clock. One data bit is transferred for each clock
cycle. Only as many clock cycles should be received as
there are data bits.
25.4.1.7 Receive Overrun Error
The receive FIFO buffer can hold two characters. An
overrun error will be generated if a third character, in its
entirety, is received before RCREG is read to access
the FIFO. When this happens the OERR bit of the
RCSTA register is set. Previous data in the FIFO will
not be overwritten. The two characters in the FIFO
buffer can be read, however, no additional characters
will be received until the error is cleared. The OERR bit
can only be cleared by clearing the overrun condition.
If the overrun error occurred when the SREN bit is set
and CREN is clear then the error is cleared by reading
RCREG. If the overrun occurred when the CREN bit is
set then the error condition is cleared by either clearing
the CREN bit of the RCSTA register or by clearing the
SPEN bit which resets the EUSART.
25.4.1.8 Receiving 9-bit Characters
The EUSART supports 9-bit character reception. When
the RX9 bit of the RCSTA register is set, the EUSART
will shift 9-bits into the RSR for each character
received. The RX9D bit of the RCSTA register is the
ninth, and Most Significant, data bit of the top unread
character in the receive FIFO. When reading 9-bit data
from the receive FIFO buffer, the RX9D data bit must
be read before reading the 8 Least Significant bits from
the RCREG.
25.4.1.9 Synchronous Master Reception
Set-up:
1. Initialize the SPBRGH, SPBRGL register pair for
the appropriate baud rate. Set or clear the
BRGH and BRG16 bits, as required, to achieve
the desired baud rate.
2. Clear the ANSEL bit for the RX pin (if applicable).
3. Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
4. Ensure bits CREN and SREN are clear.
5. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
6. If 9-bit reception is desired, set bit RX9.
7. Start reception by setting the SREN bit or for
continuous reception, set the CREN bit.
8. Interrupt flag bit RCIF will be set when reception
of a character is complete. An interrupt will be
generated if the enable bit RCIE was set.
9. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
10. Read the 8-bit received data by reading the
RCREG register.
11. If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTA
register or by clearing the SPEN bit which resets
the EUSART.
Note: If the RX/DT function is on an analog pin,
the corresponding ANSEL bit must be
cleared for the receiver to function.
Note: If the device is configured as a slave and
the TX/CK function is on an analog pin, the
corresponding ANSEL bit must be cleared.
2010 Microchip Technology Inc. Preliminary DS41413A-page 303
PIC12F/LF1822/16F/LF1823
FIGURE 25-12: SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
TABLE 25-8: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER
RECEPTION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL — SCKP BRG16 —WUE ABDEN 290
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
RCREG EUSART Receive Data Register 284*
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
SPBRGL BRG7 BRG6 BRG5 BRG4 BRG3 BRG2 BRG1 BRG0 291*
SPBRGH BRG15 BRG14 BRG13 BRG12 BRG11 BRG10 BRG9 BRG8 291*
TRISC(1) — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Master Reception.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
CREN bit
RX/DT
Write to
bit SREN
SREN bit
RCIF bit
(Interrupt)
Read
RCREG
‘0’
bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7
‘0’
Note: Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.
TX/CK pin
TX/CK pin
pin
(SCKP = 0)
(SCKP = 1)
PIC12F/LF1822/16F/LF1823
DS41413A-page 304 Preliminary 2010 Microchip Technology Inc.
25.4.2 SYNCHRONOUS SLAVE MODE
The following bits are used to configure the EUSART
for Synchronous slave operation:
• SYNC = 1
• CSRC = 0
• SREN = 0 (for transmit); SREN = 1 (for receive)
• CREN = 0 (for transmit); CREN = 1 (for receive)
• SPEN = 1
Setting the SYNC bit of the TXSTA register configures the
device for synchronous operation. Clearing the CSRC bit
of the TXSTA register configures the device as a slave.
Clearing the SREN and CREN bits of the RCSTA register
ensures that the device is in the Transmit mode,
otherwise the device will be configured to receive. Setting
the SPEN bit of the RCSTA register enables the
EUSART.
25.4.2.1 EUSART Synchronous Slave
Transmit
The operation of the Synchronous Master and Slave
modes are identical (see Section 25.4.1.3
“Synchronous Master Transmission”), except in the
case of the Sleep mode.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
1. The first character will immediately transfer to
the TSR register and transmit.
2. The second word will remain in TXREG register.
3. The TXIF bit will not be set.
4. After the first character has been shifted out of
TSR, the TXREG register will transfer the second
character to the TSR and the TXIF bit will now be
set.
5. If the PEIE and TXIE bits are set, the interrupt
will wake the device from Sleep and execute the
next instruction. If the GIE bit is also set, the
program will call the Interrupt Service Routine.
25.4.2.2 Synchronous Slave Transmission
Set-up:
1. Set the SYNC and SPEN bits and clear the
CSRC bit.
2. Clear the ANSEL bit for the CK pin (if applicable).
3. Clear the CREN and SREN bits.
4. If interrupts are desired, set the TXIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
5. If 9-bit transmission is desired, set the TX9 bit.
6. Enable transmission by setting the TXEN bit.
7. If 9-bit transmission is selected, insert the Most
Significant bit into the TX9D bit.
8. Start transmission by writing the Least
Significant 8 bits to the TXREG register.
TABLE 25-9: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE
TRANSMISSION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL —SCKPBRG16 —WUE ABDEN 290
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
TRISC(1) — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
TXREG EUSART Transmit Data Register 281*
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Slave Transmission.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 305
PIC12F/LF1822/16F/LF1823
25.4.2.3 EUSART Synchronous Slave
Reception
The operation of the Synchronous Master and Slave
modes is identical (Section 25.4.1.5 “Synchronous
Master Reception”), with the following exceptions:
• Sleep
• CREN bit is always set, therefore the receiver is
never Idle
• SREN bit, which is a “don’t care” in Slave mode
A character may be received while in Sleep mode by
setting the CREN bit prior to entering Sleep. Once the
word is received, the RSR register will transfer the data
to the RCREG register. If the RCIE enable bit is set, the
interrupt generated will wake the device from Sleep
and execute the next instruction. If the GIE bit is also
set, the program will branch to the interrupt vector.
25.4.2.4 Synchronous Slave Reception
Set-up:
1. Set the SYNC and SPEN bits and clear the
CSRC bit.
2. Clear the ANSEL bit for both the CK and DT pins
(if applicable).
3. If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
4. If 9-bit reception is desired, set the RX9 bit.
5. Set the CREN bit to enable reception.
6. The RCIF bit will be set when reception is
complete. An interrupt will be generated if the
RCIE bit was set.
7. If 9-bit mode is enabled, retrieve the Most
Significant bit from the RX9D bit of the RCSTA
register.
8. Retrieve the 8 Least Significant bits from the
receive FIFO by reading the RCREG register.
9. If an overrun error occurs, clear the error by
either clearing the CREN bit of the RCSTA
register or by clearing the SPEN bit which resets
the EUSART.
TABLE 25-10: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE
RECEPTION
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
BAUDCON ABDOVF RCIDL —SCKPBRG16 —WUE ABDEN 290
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 90
PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 92
RCREG EUSART Receive Data Register 284*
RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 289
TRISC(1) — — TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 288
Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Slave Reception.
* Page provides register information.
Note 1: PIC16F/LF1823 only.
PIC12F/LF1822/16F/LF1823
DS41413A-page 306 Preliminary 2010 Microchip Technology Inc.
25.5 EUSART Operation During Sleep
The EUSART will remain active during Sleep only in the
Synchronous Slave mode. All other modes require the
system clock; and therefore, cannot generate the
necessary signals to run the Transmit or Receive Shift
registers during Sleep.
Synchronous Slave mode uses an externally generated
clock to run the Transmit and Receive Shift registers.
25.5.1 SYNCHRONOUS RECEIVE DURING
SLEEP
To receive during Sleep, all the following conditions
must be met before entering Sleep mode:
• RCSTA and TXSTA Control registers must be
configured for Synchronous Slave Reception (see
Section 25.4.2.4 “Synchronous Slave
Reception Set-up:”).
• If interrupts are desired, set the RCIE bit of the
PIE1 register and the GIE and PEIE bits of the
INTCON register.
• The RCIF interrupt flag must be cleared by read-
ing RCREG to unload any pending characters in
the receive buffer.
Upon entering Sleep mode, the device will be ready to
accept data and clocks on the RX/DT and TX/CK pins,
respectively. When the data word has been completely
clocked in by the external device, the RCIF interrupt
flag bit of the PIR1 register will be set. Thereby, waking
the processor from Sleep.
Upon waking from Sleep, the instruction following the
SLEEP instruction will be executed. If the Global Inter-
rupt Enable (GIE) bit of the INTCON register is also set,
then the Interrupt Service Routine at address 004h will
be called.
25.5.2 SYNCHRONOUS TRANSMIT
DURING SLEEP
To transmit during Sleep, all the following conditions
must be met before entering Sleep mode:
• RCSTA and TXSTA Control registers must be
configured for Synchronous Slave Transmission
(see Section 25.4.2.2 “Synchronous Slave
Transmission Set-up:”).
• The TXIF interrupt flag must be cleared by writing
the output data to the TXREG, thereby, filling the
TSR and transmit buffer.
• If interrupts are desired, set the TXIE bit of the
PIE1 register and the PEIE bit of the INTCON
register.
• Interrupt enable bits TXIE of the PIE1 register and
PEIE of the INTCON register must set.
Upon entering Sleep mode, the device will be ready to
accept clocks on TX/CK pin and transmit data on the
RX/DT pin. When the data word in the TSR has been
completely clocked out by the external device, the
pending byte in the TXREG will transfer to the TSR and
the TXIF flag will be set. Thereby, waking the processor
from Sleep. At this point, the TXREG is available to
accept another character for transmission, which will
clear the TXIF flag.
Upon waking from Sleep, the instruction following the
SLEEP instruction will be executed. If the Global
Interrupt Enable (GIE) bit is also set then the Interrupt
Service Routine at address 0004h will be called.
2010 Microchip Technology Inc. Preliminary DS41413A-page 307
PIC12F/LF1822/16F/LF1823
26.0 CAPACITIVE SENSING
MODULE
The capacitive sensing module allows for an interaction
with an end user without a mechanical interface. In a
typical application, the capacitive sensing module is
attached to a pad on a Printed Circuit Board (PCB),
which is electrically isolated from the end user. When the
end user places their finger over the PCB pad, a
capacitive load is added, causing a frequency shift in the
capacitive sensing module. The capacitive sensing
module requires software and at least one timer
resource to determine the change in frequency. Key
features of this module include:
• Analog MUX for monitoring multiple inputs
• Capacitive sensing oscillator
• Multiple Power modes
• High power range with variable voltage references
• Multiple timer resources
• Software control
• Operation during Sleep
FIGURE 26-1: CAPACITIVE SENSING BLOCK DIAGRAM
Note 1: Reference CPSCON1 register (Register 26-2) for channels implemented on each device.
2: If CPSON = 0, disabling capacitive sensing, no channel is selected.
TMR0CS
CPS0
CPS1
CPS2
CPS3
CPS4(1)
CPS5(1)
CPS6(1)
CPSCH<3:0>
Capacitive
Sensing
Oscillator
CPSOSC
CPSON
CPSRNG<1:0>
TMR0
0
1
Set
TMR0IF
Overflow
T0XCS
0
1
T0CKI
CPSOUT
CPS7(1)
CPSCLK
FOSC/4
Timer0 Module
CPSON(2)
T1CS<1:0>
T1OSC/
T1CKI
TMR1H:TMR1L
EN
T1GSEL<1:0>
Timer1 Gate
Control Logic
T1G
FOSC
FOSC/4
Timer1 Module
SYNCC1OUT
SYNCC2OUT
0
1
Int.
Ref.
FVR
DAC
Ref+
Ref-
CPSRM
0
1
PIC12F/LF1822/16F/LF1823
DS41413A-page 308 Preliminary 2010 Microchip Technology Inc.
FIGURE 26-2: CAPACITIVE SENSING OSCILLATOR BLOCK DIAGRAM
Note 1: Module Enable and Power mode selections are not shown.
2: Comparators remain active in Noise Detection mode.
0
1
VDD
CPSCLK
Oscillator Module
CPSx SQ
R
+
-
+
-
(2)
(1)
(1) (2)
0
1
Internal
References
FVR
DAC
CPSRM
Analog Pin
Ref- Ref+
2010 Microchip Technology Inc. Preliminary DS41413A-page 309
PIC12F/LF1822/16F/LF1823
26.1 Analog MUX
The capacitive sensing module can monitor up to four
inputs for the PIC12F/LF1822 (CPSCH<3:0>) and up
to eight inputs for the PIC16F/LF1823 (CPSCH<7:0>).
See Register 26-2 for details. The capacitive sensing
inputs are defined as CPS<7:0>, as applicable to
device. To determine if a frequency change has
occurred the user must:
• Select the appropriate CPS pin by setting the
appropriate CPSCH bits of the CPSCON1 register.
• Set the corresponding ANSEL bit.
• Set the corresponding TRIS bit.
• Run the software algorithm.
Selection of the CPSx pin while the module is enabled
will cause the capacitive sensing oscillator to be on the
CPSx pin. Failure to set the corresponding ANSEL and
TRIS bits can cause the capacitive sensing oscillator to
stop, leading to false frequency readings.
26.2 Capacitive Sensing Oscillator
The capacitive sensing oscillator consists of a constant
current source and a constant current sink, to produce
a triangle waveform. The CPSOUT bit of the
CPSCON0 register shows the status of the capacitive
sensing oscillator, whether it is a sinking or sourcing
current. The oscillator is designed to drive a capacitive
load (single PCB pad) and at the same time, be a clock
source to either Timer0 or Timer1. The oscillator has
three different current settings as defined by
CPSRNG<1:0> of the CPSCON0 register. The different
current settings for the oscillator serve two purposes:
• Maximize the number of counts in a timer for a
fixed time base.
• Maximize the count differential in the timer during
a change in frequency.
26.3 Voltage References
The capacitive sensing oscillator uses voltage refer-
ences to provide two voltage thresholds for oscillation.
The upper voltage threshold is referred to as Ref+ and
the lower voltage threshold is referred to as Ref-.
The user can elect to use fixed voltage references,
which are internal to the capacitive sensing oscillator,
or variable voltage references, which are supplied by
the Fixed Voltage Reference (FVR) module and the
Digital-to-Analog Converter (DAC) module.
When the fixed voltage references are used, the VSS
voltage determines the lower threshold level (Ref-) and
the VDD voltage determines the upper threshold level
(Ref+).
When the variable voltage references are used, the
DAC voltage determines the lower threshold level
(Ref-) and the FVR voltage determines the upper
threshold level (Ref+). An advantage of using these ref-
erence sources is that oscillation frequency remains
constant with changes in VDD.
Different oscillation frequencies can be obtained
through the use of these variable voltage references.
The more the upper voltage reference level is lowered
and the more the lower voltage reference level is
raised, the higher the capacitive sensing oscillator
frequency becomes.
Selection between the voltage references is controlled
by the CPSRM bit of the CPSCON0 register. Setting
this bit selects the variable voltage references and
clearing this bit selects the fixed voltage references.
Please see Section 14.0 “Fixed Voltage Reference
(FVR)” and Section 16.0 “Digital-to-Analog Converter
(DAC) Module” for more information on configuring the
variable voltage levels.
PIC12F/LF1822/16F/LF1823
DS41413A-page 310 Preliminary 2010 Microchip Technology Inc.
26.4 Power Modes
The capacitive sensing oscillator can operate in one of
seven different power modes. The power modes are
separated into two ranges; the low range and the high
range.
When the oscillator’s low range is selected, the fixed
internal voltage references of the capacitive sensing
oscillator are being used. When the oscillator’s high
range is selected, the variable voltage references
supplied by the FVR and DAC modules are being used.
Selection between the voltage references is controlled
by the CPSRM bit of the CPSCON0 register. See
Section 26.3 “Voltage References” for more
information.
Within each range there are three distinct Power modes;
low, medium and high. Current consumption is dependent
upon the range and mode selected. Selecting Power
modes within each range is accomplished by configuring
the CPSRNG <1:0> bits in the CPSCON0 register. See
Table 26-1 for proper Power mode selection.
The remaining mode is a Noise Detection mode that
resides within the high range. The Noise Detection
mode is unique in that it disables the sinking and sourc-
ing of current on the analog pin but leaves the rest of
the oscillator circuitry active. This reduces the oscilla-
tion frequency on the analog pin to zero and also
greatly reduces the current consumed by the oscillator
module.
When noise is introduced onto the pin, the oscillator is
driven at the frequency determined by the noise. This
produces a detectable signal at the comparator output,
indicating the presence of activity on the pin.
Figure 26-2 shows a more detailed drawing of the
current sources and comparators associated with the
oscillator.
TABLE 26-1: POWER MODE SELECTION
CPSRM Range CPSRNG<1:0> Mode Nominal Current(1)
0Low
00 Off 0.0 A
01 Low 0.1 A
10 Medium 1.2 A
11 High 18 A
1High
00 Noise Detection 0.0 A
01 Low 9 A
10 Medium 30 A
11 High 100 A
Note 1: See Section 29.0 “Electrical Specifications” for more information.
2010 Microchip Technology Inc. Preliminary DS41413A-page 311
PIC12F/LF1822/16F/LF1823
26.5 Timer Resources
To measure the change in frequency of the capacitive
sensing oscillator, a fixed time base is required. For the
period of the fixed time base, the capacitive sensing
oscillator is used to clock either Timer0 or Timer1. The
frequency of the capacitive sensing oscillator is equal
to the number of counts in the timer, divided by the
period of the fixed time base.
26.6 Fixed Time Base
To measure the frequency of the capacitive sensing
oscillator, a fixed time base is required. Any timer
resource or software loop can be used to establish the
fixed time base. It is up to the end user to determine the
method in which the fixed time base is generated.
26.6.1 TIMER0
To select Timer0 as the timer resource for the capacitive
sensing module:
• Set the T0XCS bit of the CPSCON0 register.
• Clear the TMR0CS bit of the OPTION register.
When Timer0 is chosen as the timer resource, the
capacitive sensing oscillator will be the clock source for
Timer0. Refer to Section 19.0 “Timer0 Module” for
additional information.
26.6.2 TIMER1
To select Timer1 as the timer resource for the
capacitive sensing module, set the TMR1CS<1:0> of
the T1CON register to ‘11’. When Timer1 is chosen as
the timer resource, the capacitive sensing oscillator will
be the clock source for Timer1. Because the Timer1
module has a gate control, developing a time base for
the frequency measurement can be simplified by using
the Timer0 overflow flag.
It is recommend that the Timer0 overflow flag, in con-
junction with the Toggle mode of the Timer1 Gate, be
used to develop the fixed time base required by the
software portion of the capacitive sensing module.
Refer to Section 20.12 “Timer1 Gate Control Regis-
ter” for additional information.
TABLE 26-2: TIMER1 ENABLE FUNCTION
26.7 Software Control
The software portion of the capacitive sensing module
is required to determine the change in frequency of the
capacitive sensing oscillator. This is accomplished by
the following:
• Setting a fixed time base to acquire counts on
Timer0 or Timer1.
• Establishing the nominal frequency for the
capacitive sensing oscillator.
• Establishing the reduced frequency for the capac-
itive sensing oscillator due to an additional capac-
itive load.
• Set the frequency threshold.
26.7.1 NOMINAL FREQUENCY
(NO CAPACITIVE LOAD)
To determine the nominal frequency of the capacitive
sensing oscillator:
• Remove any extra capacitive load on the selected
CPSx pin.
• At the start of the fixed time base, clear the timer
resource.
• At the end of the fixed time base save the value in
the timer resource.
The value of the timer resource is the number of
oscillations of the capacitive sensing oscillator for the
given time base. The frequency of the capacitive
sensing oscillator is equal to the number of counts on
in the timer, divided by the period of the fixed time base.
26.7.2 REDUCED FREQUENCY
(ADDITIONAL CAPACITIVE LOAD)
The extra capacitive load will cause the frequency of the
capacitive sensing oscillator to decrease. To determine
the reduced frequency of the capacitive sensing
oscillator:
• Add a typical capacitive load on the selected
CPSx pin.
• Use the same fixed time base as the nominal
frequency measurement.
• At the start of the fixed time base, clear the timer
resource.
• At the end of the fixed time base, save the value
in the timer resource.
The value of the timer resource is the number of oscil-
lations of the capacitive sensing oscillator with an addi-
tional capacitive load. The frequency of the capacitive
sensing oscillator is equal to the number of counts on
in the timer, divided by the period of the fixed time base.
This frequency should be less than the value obtained
during the nominal frequency measurement.
Note: The fixed time base can not be generated
by the timer resource that the capacitive
sensing oscillator is clocking.
TMR1ON TMR1GE Timer1 Operation
00 Off
01 Off
10 On
11Count Enabled by input
PIC12F/LF1822/16F/LF1823
DS41413A-page 312 Preliminary 2010 Microchip Technology Inc.
26.7.3 FREQUENCY THRESHOLD
The frequency threshold should be placed midway
between the value of nominal frequency and the
reduced frequency of the capacitive sensing oscillator.
Refer to Application Note AN1103, “Software Handling
for Capacitive Sensing” (DS01103) for more detailed
information on the software required for capacitive
sensing module.
26.8 Operation during Sleep
The capacitive sensing oscillator will continue to run as
long as the module is enabled, independent of the part
being in Sleep. In order for the software to determine if
a frequency change has occurred, the part must be
awake. However, the part does not have to be awake
when the timer resource is acquiring counts.
Note: For more information on general capacitive
sensing refer to Application Notes:
• AN1101, “Introduction to Capacitive
Sensing” (DS01101)
• AN1102, “Layout and Physical Design
Guidelines for Capacitive Sensing”
(DS01102)
Note: Timer0 does not operate when in Sleep,
and therefore, cannot be used for
capacitive sense measurements in Sleep.
2010 Microchip Technology Inc. Preliminary DS41413A-page 313
PIC12F/LF1822/16F/LF1823
REGISTER 26-1: CPSCON0: CAPACITIVE SENSING CONTROL REGISTER 0
R/W-0/0 R/W-0/0 U-0 U-0 R/W-0/0 R/W-0/0 R-0/0 R/W-0/0
CPSON CPSRM —— CPSRNG<1:0> CPSOUT T0XCS
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7 CPSON: Capacitive Sensing Module Enable bit
1 = Capacitive sensing module is enabled
0 = Capacitive sensing module is disabled
bit 6 CPSRM: Capacitive Sensing Reference Mode bit
1 = Capacitive sensing module is in high range. DAC and FVR provide oscillator voltage references.
0 = Capacitive sensing module is in the low range. Internal oscillator voltage references are used.
bit 5-4 Unimplemented: Read as ‘0’
bit 3-2 CPSRNG<1:0>: Capacitive Sensing Current Range bit
If CPSRM = 0 (low range):
00 = Oscillator is off
01 = Oscillator is in Low Range. Charge/Discharge Current is nominally 0.1 µA
10 = Oscillator is in Medium Range. Charge/Discharge Current is nominally 1.2 µA
11 = Oscillator is in High Range. Charge/Discharge Current is nominally 18 µA
If CPSRM = 1 (high range):
00 = Oscillator is on. Noise Detection mode. No Charge/Discharge current is supplied.
01 = Oscillator is in Low Range. Charge/Discharge Current is nominally 9 µA
10 = Oscillator is in Medium Range. Charge/Discharge Current is nominally 30 µA
11 = Oscillator is in High Range. Charge/Discharge Current is nominally 100 µA
bit 1 CPSOUT: Capacitive Sensing Oscillator Status bit
1 = Oscillator is sourcing current (Current flowing out of the pin)
0 = Oscillator is sinking current (Current flowing into the pin)
bit 0 T0XCS: Timer0 External Clock Source Select bit
If TMR0CS = 1:
The T0XCS bit controls which clock external to the core/Timer0 module supplies Timer0:
1 = Timer0 clock source is the capacitive sensing oscillator
0 = Timer0 clock source is the T0CKI pin
If TMR0CS = 0:
Timer0 clock source is controlled by the core/Timer0 module and is FOSC/4
PIC12F/LF1822/16F/LF1823
DS41413A-page 314 Preliminary 2010 Microchip Technology Inc.
TABLE 26-3: SUMMARY OF REGISTERS ASSOCIATED WITH CAPACITIVE SENSING
REGISTER 26-2: CPSCON1: CAPACITIVE SENSING CONTROL REGISTER 1
U-0 U-0 U-0 U-0 R/W-0/0(1) R/W-0/0 R/W-0/0 R/W-0/0
— — — — CPSCH<3:2>(2) CPSCH<1:0>
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set ‘0’ = Bit is cleared
bit 7-4 Unimplemented: Read as ‘0’
bit 3-0 CPSCH<3:0>: Capacitive Sensing Channel Select bits
If CPSON = 0:
These bits are ignored. No channel is selected.
If CPSON = 1:
0000 = channel 0, (CPS0)
0001 = channel 1, (CPS1)
0010 = channel 2, (CPS2)
0011 = channel 3, (CPS3)
0100 = channel 4, (CPS4)(1)
0101 = channel 5, (CPS5)(1)
0110 = channel 6, (CPS6)(1)
0111 = channel 7, (CPS7)(1)
1000 = Reserved. Do not use.
•
•
•
1111 = Reserved. Do not use.
Note 1: These channels are only implemented on the PIC16F/LF1823.
2: PIC16F/LF1823 only.
Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register
on Page
ANSELA ———ANSA4— ANSA2 ANSA1 ANSA0 122
ANSELC(1) ———— ANSC3 ANSC2 ANSC1 ANSC0 126
CPSCON0 CPSON CPSRM —— CPSRNG1 CPSRNG0 CPSOUT T0XCS 313
CPSCON1 ———— CPSCH3(1) CPSCH2(1) CPSCH1 CPSCH0 314
INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 89
OPTION_REG WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 171
T1CON TMR1CS1 TMR1CS0 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC —TMR1ON
180
TRISA — — TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 121
TRISC(1) —— TRISC5 TRISC4 TRISC3 TRISC2 TRISC1 TRISC0 125
Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by the capacitive sensing module.
Note 1: PIC16F/LF1823 only.
2010 Microchip Technology Inc. Preliminary DS41413A-page 315
PIC12F/LF1822/16F/LF1823
27.0 IN-CIRCUIT SERIAL
PROGRAMMING™ (ICSP™)
ICSP™ programming allows customers to manufacture
circuit boards with unprogrammed devices. Programming
can be done after the assembly process allowing the
device to be programmed with the most recent firmware
or a custom firmware. Five pins are needed for ICSP™
programming:
• ICSPCLK
• ICSPDAT
•MCLR
/VPP
•VDD
•VSS
In Program/Verify mode the program memory, user IDs
and the Configuration Words are programmed through
serial communications. The ICSPDAT pin is a bidirec-
tional I/O used for transferring the serial data and the
ICSPCLK pin is the clock input. For more information on
ICSP™ refer to the “PIC16F/LF182X/PIC12F/LF1822
Memory Programming Specification” (DS41403).
27.1 High-Voltage Programming Entry
Mode
The device is placed into High-Voltage Programming
Entry mode by holding the ICSPCLK and ICSPDAT
pins low then raising the voltage on MCLR/VPP to VIHH.
Some programmers produce VPP greater than VIHH
(9.0V), an external circuit is required to limit the VPP
voltage. See Figure 27-1 for example circuit.
FIGURE 27-1: VPP LIMITER EXAMPLE CIRCUIT
VREF
VPP
VDD
VSS
ICSP_DATA
ICSP_CLOCK
NC
RJ11-6PIN
RJ11-6PIN
R1
270 Ohm
To MPL A B ® ICD 2 To Targ et Bo ar d
1
2
3
4
5
61
2
3
4
5
6
R2 R3
10k 1% 24k 1%
U1
LM431BCMX
A
2
3
6
7
8
A
A
A
K
NC
NC
1
4
5
Note: The ICD 2 produces a VPP voltage greater
than the maximum VPP specification of the
PIC12F/LF1822/16F/LF1823.
PIC12F/LF1822/16F/LF1823
DS41413A-page 316 Preliminary 2010 Microchip Technology Inc.
27.2 Low-Voltage Programming Entry
Mode
The Low-Voltage Programming Entry mode allows the
PIC12F/LF1822/16F/LF1823 devices to be
programmed using VDD only, without high voltage.
When the LVP bit of Configuration Word 2 is set to ‘1’,
the low-voltage ICSP programming entry is enabled. To
disable the Low-Voltage ICSP mode, the LVP bit must
be programmed to ‘0’.
Entry into the Low-Voltage Programming Entry mode
requires the following steps:
1. MCLR is brought to VIL.
2. A 32-bit key sequence is presented on
ICSPDAT, while clocking ICSPCLK.
Once the key sequence is complete, MCLR must be
held at VIL for as long as Program/Verify mode is to be
maintained.
If low-voltage programming is enabled (LVP = 1), the
MCLR Reset function is automatically enabled and
cannot be disabled. See Section 7.3 “MCLR” for more
information.
The LVP bit can only be reprogrammed to ‘0’ by using
the High-Voltage Programming mode.
27.3 Common Programming Interfaces
Connection to a target device is typically done through
an ICSP™ header. A commonly found connector on
development tools is the RJ-11 in the 6P6C (6 pin, 6
connector) configuration. See Figure 27-2.
FIGURE 27-2: ICD RJ-11 STYLE
CONNECTOR INTERFACE
Another connector often found in use with the PICkit™
programmers is a standard 6-pin header with 0.1 inch
spacing. Refer to Figure 27-3.
FIGURE 27-3: PICkit™ STYLE CONNECTOR INTERFACE
1
2
3
4
5
6
Target
Bottom Side
PC Board
VPP/MCLR VSS
ICSPCLK
VDD
ICSPDAT
NC
Pin Description*
1 = VPP/MCLR
2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
5 = ICSPCLK
6 = No Connect
1
2
3
4
5
6
* The 6-pin header (0.100" spacing) accepts 0.025" square pins.
Pin Description*
1 = VPP/MCLR
2 = VDD Target
3 = VSS (ground)
4 = ICSPDAT
5 = ICSPCLK
6 = No Connect
Pin 1 Indicator
2010 Microchip Technology Inc. Preliminary DS41413A-page 317
PIC12F/LF1822/16F/LF1823
For additional interface recommendations, refer to your
specific device programmer manual prior to PCB
design.
It is recommended that isolation devices be used to
separate the programming pins from other circuitry.
The type of isolation is highly dependent on the specific
application and may include devices such as resistors,
diodes, or even jumpers. See Figure 27-4 for more
information.
FIGURE 27-4: TYPICAL CONNECTION FOR ICSP™ PROGRAMMING
VDD
VPP
VSS
External
Device to be
Data
Clock
VDD
MCLR/VPP
VSS
ICSPDAT
ICSPCLK
**
*
To Normal Connections
*Isolation devices (as required).
Programming
Signals Programmed
VDD
PIC12F/LF1822/16F/LF1823
DS41413A-page 318 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 319
PIC12F/LF1822/16F/LF1823
28.0 INSTRUCTION SET SUMMARY
Each PIC16 instruction is a 14-bit word containing the
operation code (opcode) and all required operands.
The opcodes are broken into three broad categories.
• Byte Oriented
• Bit Oriented
• Literal and Control
The literal and control category contains the most var-
ied instruction word format.
Table 28-3 lists the instructions recognized by the
MPASMTM assembler.
All instructions are executed within a single instruction
cycle, with the following exceptions, which may take
two or three cycles:
• Subroutine takes two cycles (CALL, CALLW)
• Returns from interrupts or subroutines take two
cycles (RETURN, RETLW, RETFIE)
• Program branching takes two cycles (GOTO, BRA,
BRW, BTFSS, BTFSC, DECFSZ, INCSFZ)
• One additional instruction cycle will be used when
any instruction references an indirect file register
and the file select register is pointing to program
memory.
One instruction cycle consists of 4 oscillator cycles; for
an oscillator frequency of 4 MHz, this gives a nominal
instruction execution rate of 1 MHz.
All instruction examples use the format ‘0xhh’ to
represent a hexadecimal number, where ‘h’ signifies a
hexadecimal digit.
28.1 Read-Modify-Write Operations
Any instruction that specifies a file register as part of
the instruction performs a Read-Modify-Write (R-M-W)
operation. The register is read, the data is modified,
and the result is stored according to either the instruc-
tion, or the destination designator ‘d’. A read operation
is performed on a register even if the instruction writes
to that register.
TABLE 28-1: OPCODE FIELD
DESCRIPTIONS
TABLE 28-2: ABBREVIATION
DESCRIPTIONS
Field Description
fRegister file address (0x00 to 0x7F)
WWorking register (accumulator)
bBit address within an 8-bit file register
kLiteral field, constant data or label
xDon’t care location (= 0 or 1).
The assembler will generate code with x = 0.
It is the recommended form of use for
compatibility with all Microchip software tools.
dDestination select; d = 0: store result in W,
d = 1: store result in file register f.
Default is d = 1.
nFSR or INDF number. (0-1)
mm Pre-post increment-decrement mode
selection
Field Description
PC Program Counter
TO Time-out bit
CCarry bit
DC Digit carry bit
ZZero bit
PD Power-down bit
PIC12F/LF1822/16F/LF1823
DS41413A-page 320 Preliminary 2010 Microchip Technology Inc.
FIGURE 28-1: GENERAL FORMAT FOR
INSTRUCTIONS
Byte-oriented file register operations
13 8 7 6 0
d = 0 for destination W
OPCODE d f (FILE #)
d = 1 for destination f
f = 7-bit file register address
Bit-oriented file register operations
13 10 9 7 6 0
OPCODE b (BIT #) f (FILE #)
b = 3-bit bit address
f = 7-bit file register address
Literal and control operations
13 8 7 0
OPCODE k (literal)
k = 8-bit immediate value
13 11 10 0
OPCODE k (literal)
k = 11-bit immediate value
General
CALL and GOTO instructions only
MOVLP instruction only
13 5 4 0
OPCODE k (literal)
k = 5-bit immediate value
MOVLB instruction only
13 9 8 0
OPCODE k (literal)
k = 9-bit immediate value
BRA instruction only
FSR Offset instructions
13 7 6 5 0
OPCODE n k (literal)
n = appropriate FSR
FSR Increment instructions
13 7 6 0
OPCODE k (literal)
k = 7-bit immediate value
13 3 2 1 0
OPCODE n m (mode)
n = appropriate FSR
m = 2-bit mode value
k = 6-bit immediate value
13 0
OPCODE
OPCODE only
2010 Microchip Technology Inc. Preliminary DS41413A-page 321
PIC12F/LF1822/16F/LF1823
TABLE 28-3: PIC12F/LF1822/16F/LF1823 ENHANCED INSTRUCTION SET
Mnemonic,
Operands Description Cycles
14-Bit Opcode Status
Affected Notes
MSb LSb
BYTE-ORIENTED FILE REGISTER OPERATIONS
ADDWF
ADDWFC
ANDWF
ASRF
LSLF
LSRF
CLRF
CLRW
COMF
DECF
INCF
IORWF
MOVF
MOVWF
RLF
RRF
SUBWF
SUBWFB
SWAPF
XORWF
f, d
f, d
f, d
f, d
f, d
f, d
f
–
f, d
f, d
f, d
f, d
f, d
f
f, d
f, d
f, d
f, d
f, d
f, d
Add W and f
Add with Carry W and f
AND W with f
Arithmetic Right Shift
Logical Left Shift
Logical Right Shift
Clear f
Clear W
Complement f
Decrement f
Increment f
Inclusive OR W with f
Move f
Move W to f
Rotate Left f through Carry
Rotate Right f through Carry
Subtract W from f
Subtract with Borrow W from f
Swap nibbles in f
Exclusive OR W with f
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
00
11
00
11
11
11
00
00
00
00
00
00
00
00
00
00
00
11
00
00
0111
1101
0101
0111
0101
0110
0001
0001
1001
0011
1010
0100
1000
0000
1101
1100
0010
1011
1110
0110
dfff
dfff
dfff
dfff
dfff
dfff
lfff
0000
dfff
dfff
dfff
dfff
dfff
1fff
dfff
dfff
dfff
dfff
dfff
dfff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
00xx
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
C, DC, Z
C, DC, Z
Z
C, Z
C, Z
C, Z
Z
Z
Z
Z
Z
Z
Z
C
C
C, DC, Z
C, DC, Z
Z
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
BYTE ORIENTED SKIP OPERATIONS
DECFSZ
INCFSZ
f, d
f, d
Decrement f, Skip if 0
Increment f, Skip if 0
1(2)
1(2)
00
00
1011
1111
dfff
dfff
ffff
ffff
1, 2
1, 2
BIT-ORIENTED FILE REGISTER OPERATIONS
BCF
BSF
f, b
f, b
Bit Clear f
Bit Set f
1
1
01
01
00bb
01bb
bfff
bfff
ffff
ffff
2
2
BIT-ORIENTED SKIP OPERATIONS
BTFSC
BTFSS
f, b
f, b
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
1 (2)
1 (2)
01
01
10bb
11bb
bfff
bfff
ffff
ffff
1, 2
1, 2
LITERAL OPERATIONS
ADDLW
ANDLW
IORLW
MOVLB
MOVLP
MOVLW
SUBLW
XORLW
k
k
k
k
k
k
k
k
Add literal and W
AND literal with W
Inclusive OR literal with W
Move literal to BSR
Move literal to PCLATH
Move literal to W
Subtract W from literal
Exclusive OR literal with W
1
1
1
1
1
1
1
1
11
11
11
00
11
11
11
11
1110
1001
1000
0000
0001
0000
1100
1010
kkkk
kkkk
kkkk
001k
1kkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
C, DC, Z
Z
Z
C, DC, Z
Z
Note 1: If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle
is executed as a NOP.
2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require one
additional instruction cycle.
PIC12F/LF1822/16F/LF1823
DS41413A-page 322 Preliminary 2010 Microchip Technology Inc.
TABLE 28-3: PIC12F/LF1822/16F/LF1823 ENHANCED INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands Description Cycles
14-Bit Opcode Status
Affected Notes
MSb LSb
CONTROL OPERATIONS
BRA
BRW
CALL
CALLW
GOTO
RETFIE
RETLW
RETURN
k
–
k
–
k
k
k
–
Relative Branch
Relative Branch with W
Call Subroutine
Call Subroutine with W
Go to address
Return from interrupt
Return with literal in W
Return from Subroutine
2
2
2
2
2
2
2
2
11
00
10
00
10
00
11
00
001k
0000
0kkk
0000
1kkk
0000
0100
0000
kkkk
0000
kkkk
0000
kkkk
0000
kkkk
0000
kkkk
1011
kkkk
1010
kkkk
1001
kkkk
1000
INHERENT OPERATIONS
CLRWDT
NOP
OPTION
RESET
SLEEP
TRIS
–
–
–
–
–
f
Clear Watchdog Timer
No Operation
Load OPTION_REG register with W
Software device Reset
Go into Standby mode
Load TRIS register with W
1
1
1
1
1
1
00
00
00
00
00
00
0000
0000
0000
0000
0000
0000
0110
0000
0110
0000
0110
0110
0100
0000
0010
0001
0011
0fff
TO, PD
TO, PD
C-COMPILER OPTIMIZED
ADDFSR
MOVIW
MOVWI
n, k
n
k[n]
n
k[n]
Add Literal k to FSR, n = FSR0 or FSR1
Move indirect to W, n = FSR0 or FSR1, with
pre/post inc/dec modifier.
Move INDFn to W, Indexed Indirect.
Move W to indirect, n = FSR0 or FSR1, with
pre/post inc/dec modifier.
Move W to INDFn, Indexed Indirect.
1
1
1
1
1
11
00
11
00
11
0001
0000
1111
0000
1111
0nkk
0001
0nkk
0001
1nkk
kkkk
0nmm
kkkk
1nmm
kkkk
Z
Z
2
2
2
2
Note 1: If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle
is executed as a NOP.
2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require
one additional instruction cycle.
2010 Microchip Technology Inc. Preliminary DS41413A-page 323
PIC12F/LF1822/16F/LF1823
28.2 Instruction Descriptions
ADDFSR Add Literal to FSRn
Syntax: [ label ] ADDFSR FSRn, k
Operands: -32 k 31
n [ 0, 1]
Operation: FSR(n) + k FSR(n)
Status Affected: None
Description: The signed 6-bit literal ‘k’ is added to
the contents of the FSRnH:FSRnL
register pair.
FSRn is limited to the range
0000h-FFFFh. Moving beyond these
bounds will cause the FSR to
wrap-around.
ADDLW Add literal and W
Syntax: [ label ] ADDLW k
Operands: 0 k 255
Operation: (W) + k (W)
Status Affected: C, DC, Z
Description: The contents of the W register are
added to the eight-bit literal ‘k’ and the
result is placed in the W register.
ADDWF Add W and f
Syntax: [ label ] ADDWF f,d
Operands: 0 f 127
d 0,1
Operation: (W) + (f) (destination)
Status Affected: C, DC, Z
Description: Add the contents of the W register
with register ‘f’. If ‘d’ is ‘0’, the result is
stored in the W register. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
ADDWFC ADD W and CARRY bit to f
Syntax: [ label ] ADDWFC f {,d}
Operands: 0 f 127
d [0,1]
Operation: (W) + (f) + (C) dest
Status Affected: C, DC, Z
Description: Add W, the Carry flag and data mem-
ory location ‘f’. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed in data memory location ‘f’.
ANDLW AND literal with W
Syntax: [ label ] ANDLW k
Operands: 0 k 255
Operation: (W) .AND. (k) (W)
Status Affected: Z
Description: The contents of W register are
AND’ed with the eight-bit literal ‘k’.
The result is placed in the W register.
ANDWF AND W with f
Syntax: [ label ] ANDWF f,d
Operands: 0 f 127
d 0,1
Operation: (W) .AND. (f) (destination)
Status Affected: Z
Description: AND the W register with register ‘f’. If
‘d’ is ‘0’, the result is stored in the W
register. If ‘d’ is ‘1’, the result is stored
back in register ‘f’.
ASRF Arithmetic Right Shift
Syntax: [ label ] ASRF f {,d}
Operands: 0 f 127
d [0,1]
Operation: (f<7>) dest<7>
(f<7:1>) dest<6:0>,
(f<0>) C,
Status Affected: C, Z
Description: The contents of register ‘f’ are shifted
one bit to the right through the Carry
flag. The MSb remains unchanged. If
‘d’ is ‘0’, the result is placed in W. If ‘d’
is ‘1’, the result is stored back in reg-
ister ‘f’.
register f C
PIC12F/LF1822/16F/LF1823
DS41413A-page 324 Preliminary 2010 Microchip Technology Inc.
BCF Bit Clear f
Syntax: [ label ] BCF f,b
Operands: 0 f 127
0 b 7
Operation: 0 (f<b>)
Status Affected: None
Description: Bit ‘b’ in register ‘f’ is cleared.
BRA Relative Branch
Syntax: [ label ] BRA label
[ label ] BRA $+k
Operands: -256 label - PC + 1 255
-256 k 255
Operation: (PC) + 1 + k PC
Status Affected: None
Description: Add the signed 9-bit literal ‘k’ to the
PC. Since the PC will have incre-
mented to fetch the next instruction,
the new address will be PC + 1 + k.
This instruction is a two-cycle instruc-
tion. This branch has a limited range.
BRW Relative Branch with W
Syntax: [ label ] BRW
Operands: None
Operation: (PC) + (W) PC
Status Affected: None
Description: Add the contents of W (unsigned) to
the PC. Since the PC will have incre-
mented to fetch the next instruction,
the new address will be PC + 1 + (W).
This instruction is a two-cycle instruc-
tion.
BSF Bit Set f
Syntax: [ label ] BSF f,b
Operands: 0 f 127
0 b 7
Operation: 1 (f<b>)
Status Affected: None
Description: Bit ‘b’ in register ‘f’ is set.
BTFSC Bit Test f, Skip if Clear
Syntax: [ label ] BTFSC f,b
Operands: 0 f 127
0 b 7
Operation: skip if (f<b>) = 0
Status Affected: None
Description: If bit ‘b’ in register ‘f’ is ‘1’, the next
instruction is executed.
If bit ‘b’, in register ‘f’, is ‘0’, the next
instruction is discarded, and a NOP is
executed instead, making this a
2-cycle instruction.
BTFSS Bit Test f, Skip if Set
Syntax: [ label ] BTFSS f,b
Operands: 0 f 127
0 b < 7
Operation: skip if (f<b>) = 1
Status Affected: None
Description: If bit ‘b’ in register ‘f’ is ‘0’, the next
instruction is executed.
If bit ‘b’ is ‘1’, then the next
instruction is discarded and a NOP is
executed instead, making this a
2-cycle instruction.
2010 Microchip Technology Inc. Preliminary DS41413A-page 325
PIC12F/LF1822/16F/LF1823
CALL Call Subroutine
Syntax: [ label ] CALL k
Operands: 0 k 2047
Operation: (PC)+ 1 TOS,
k PC<10:0>,
(PCLATH<4:3>) PC<12:11>
Status Affected: None
Description: Call Subroutine. First, return address
(PC + 1) is pushed onto the stack.
The eleven-bit immediate address is
loaded into PC bits <10:0>. The upper
bits of the PC are loaded from
PCLATH. CALL is a two-cycle instruc-
tion.
CALLW Subroutine Call With W
Syntax: [ label ] CALLW
Operands: None
Operation: (PC) +1 TOS,
(W) PC<7:0>,
(PCLATH<6:0>) PC<14:8>
Status Affected: None
Description: Subroutine call with W. First, the
return address (PC + 1) is pushed
onto the return stack. Then, the con-
tents of W is loaded into PC<7:0>,
and the contents of PCLATH into
PC<14:8>. CALLW is a two-cycle
instruction.
CLRF Clear f
Syntax: [ label ] CLRF f
Operands: 0 f 127
Operation: 00h (f)
1 Z
Status Affected: Z
Description: The contents of register ‘f’ are cleared
and the Z bit is set.
CLRW Clear W
Syntax: [ label ] CLRW
Operands: None
Operation: 00h (W)
1 Z
Status Affected: Z
Description: W register is cleared. Zero bit (Z) is
set.
CLRWDT Clear Watchdog Timer
Syntax: [ label ] CLRWDT
Operands: None
Operation: 00h WDT
0 WDT prescaler,
1 TO
1 PD
Status Affected: TO, PD
Description: CLRWDT instruction resets the Watch-
dog Timer. It also resets the prescaler
of the WDT.
Status bits TO and PD are set.
COMF Complement f
Syntax: [ label ] COMF f,d
Operands: 0 f 127
d [0,1]
Operation: (f) (destination)
Status Affected: Z
Description: The contents of register ‘f’ are com-
plemented. If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
DECF Decrement f
Syntax: [ label ] DECF f,d
Operands: 0 f 127
d [0,1]
Operation: (f) - 1 (destination)
Status Affected: Z
Description: Decrement register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W
register. If ‘d’ is ‘1’, the result is stored
back in register ‘f’.
PIC12F/LF1822/16F/LF1823
DS41413A-page 326 Preliminary 2010 Microchip Technology Inc.
DECFSZ Decrement f, Skip if 0
Syntax: [ label ] DECFSZ f,d
Operands: 0 f 127
d [0,1]
Operation: (f) - 1 (destination);
skip if result = 0
Status Affected: None
Description: The contents of register ‘f’ are decre-
mented. If ‘d’ is ‘0’, the result is placed
in the W register. If ‘d’ is ‘1’, the result
is placed back in register ‘f’.
If the result is ‘1’, the next instruction is
executed. If the result is ‘0’, then a
NOP is executed instead, making it a
2-cycle instruction.
GOTO Unconditional Branch
Syntax: [ label ] GOTO k
Operands: 0 k 2047
Operation: k PC<10:0>
PCLATH<4:3> PC<12:11>
Status Affected: None
Description: GOTO is an unconditional branch. The
eleven-bit immediate value is loaded
into PC bits <10:0>. The upper bits of
PC are loaded from PCLATH<4:3>.
GOTO is a two-cycle instruction.
INCF Increment f
Syntax: [ label ] INCF f,d
Operands: 0 f 127
d [0,1]
Operation: (f) + 1 (destination)
Status Affected: Z
Description: The contents of register ‘f’ are incre-
mented. If ‘d’ is ‘0’, the result is placed
in the W register. If ‘d’ is ‘1’, the result
is placed back in register ‘f’.
INCFSZ Increment f, Skip if 0
Syntax: [ label ] INCFSZ f,d
Operands: 0 f 127
d [0,1]
Operation: (f) + 1 (destination),
skip if result = 0
Status Affected: None
Description: The contents of register ‘f’ are incre-
mented. If ‘d’ is ‘0’, the result is placed
in the W register. If ‘d’ is ‘1’, the result
is placed back in register ‘f’.
If the result is ‘1’, the next instruction is
executed. If the result is ‘0’, a NOP is
executed instead, making it a 2-cycle
instruction.
IORLW Inclusive OR literal with W
Syntax: [ label ] IORLW k
Operands: 0 k 255
Operation: (W) .OR. k (W)
Status Affected: Z
Description: The contents of the W register are
OR’ed with the eight-bit literal ‘k’. The
result is placed in the W register.
IORWF Inclusive OR W with f
Syntax: [ label ] IORWF f,d
Operands: 0 f 127
d [0,1]
Operation: (W) .OR. (f) (destination)
Status Affected: Z
Description: Inclusive OR the W register with regis-
ter ‘f’. If ‘d’ is ‘0’, the result is placed in
the W register. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
2010 Microchip Technology Inc. Preliminary DS41413A-page 327
PIC12F/LF1822/16F/LF1823
LSLF Logical Left Shift
Syntax: [ label ] LSLF f {,d}
Operands: 0 f 127
d [0,1]
Operation: (f<7>) C
(f<6:0>) dest<7:1>
0 dest<0>
Status Affected: C, Z
Description: The contents of register ‘f’ are shifted
one bit to the left through the Carry flag.
A ‘0’ is shifted into the LSb. If ‘d’ is ‘0’,
the result is placed in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’.
LSRF Logical Right Shift
Syntax: [ label ] LSLF f {,d}
Operands: 0 f 127
d [0,1]
Operation: 0 dest<7>
(f<7:1>) dest<6:0>,
(f<0>) C,
Status Affected: C, Z
Description: The contents of register ‘f’ are shifted
one bit to the right through the Carry
flag. A ‘0’ is shifted into the MSb. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is ‘1’,
the result is stored back in register ‘f’.
register f 0
C
register f C0
MOVF Move f
Syntax: [ label ] MOVF f,d
Operands: 0 f 127
d [0,1]
Operation: (f) (dest)
Status Affected: Z
Description: The contents of register f is moved to
a destination dependent upon the
status of d. If d = 0,
destination is W register. If d = 1, the
destination is file register f itself. d = 1
is useful to test a file register since
status flag Z is affected.
Words: 1
Cycles: 1
Example: MOVF FSR, 0
After Instruction
W = value in FSR register
Z= 1
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DS41413A-page 328 Preliminary 2010 Microchip Technology Inc.
MOVIW Move INDFn to W
Syntax: [ label ] MOVIW ++FSRn
[ label ] MOVIW --FSRn
[ label ] MOVIW FSRn++
[ label ] MOVIW FSRn--
[ label ] MOVIW k[FSRn]
Operands: n [0,1]
-32 k 31
If not present, k = 0.
Operation: INDFn W
Effective address is determined by
• FSR + 1 (preincrement)
• FSR - 1 (predecrement)
• FSR + k (relative offset)
After the Move, the FSR value will be
either:
• FSR + 1 (all increments)
• FSR - 1 (all decrements)
• Unchanged
Status Affected: Z
Mode Syntax
Preincrement ++FSRn
Predecrement --FSRn
Postincrement FSRn++
Postdecrement FSRn--
Description: This instruction is used to move data
between W and one of the indirect
registers (INDFn). Before/after this
move, the pointer (FSRn) is updated by
pre/post incrementing/decrementing it.
Note: The INDFn registers are not
physical registers. Any instruction that
accesses an INDFn register actually
accesses the register at the address
specified by the FSRn.
FSRn is limited to the range 0000h -
FFFFh. Incrementing/decrementing it
beyond these bounds will cause it to
wrap-around.
MOVLB Move literal to BSR
Syntax: [ label ] MOVLB k
Operands: 0 k 15
Operation: k BSR
Status Affected: None
Description: The five-bit literal ‘k’ is loaded into the
Bank Select Register (BSR).
MOVLP Move literal to PCLATH
Syntax: [ label ] MOVLP k
Operands: 0 k 127
Operation: k PCLATH
Status Affected: None
Description: The seven-bit literal ‘k’ is loaded into the
PCLATH register.
MOVLW Move literal to W
Syntax: [ label ] MOVLW k
Operands: 0 k 255
Operation: k (W)
Status Affected: None
Description: The eight-bit literal ‘k’ is loaded into W
register. The “don’t cares” will assem-
ble as ‘0’s.
Words: 1
Cycles: 1
Example: MOVLW 0x5A
After Instruction
W = 0x5A
MOVWF Move W to f
Syntax: [ label ] MOVWF f
Operands: 0 f 127
Operation: (W) (f)
Status Affected: None
Description: Move data from W register to register
‘f’.
Words: 1
Cycles: 1
Example: MOVWF OPTION
Before Instruction
OPTION = 0xFF
W = 0x4F
After Instruction
OPTION = 0x4F
W = 0x4F
2010 Microchip Technology Inc. Preliminary DS41413A-page 329
PIC12F/LF1822/16F/LF1823
MOVWI Move W to INDFn
Syntax: [ label ] MOVWI ++FSRn
[ label ] MOVWI --FSRn
[ label ] MOVWI FSRn++
[ label ] MOVWI FSRn--
[ label ] MOVWI k[FSRn]
Operands: n [0,1].
-32 k 31
If not present, k = 0.
Operation: W INDFn
Effective address is determined by
• FSR + 1 (preincrement)
• FSR - 1 (predecrement)
• FSR + k (relative offset)
After the Move, the FSR value will be
either:
• FSR + 1 (all increments)
• FSR - 1 (all decrements)
Unchanged
Status Affected: None
Mode Syntax
Preincrement ++FSRn
Predecrement --FSRn
Postincrement FSRn++
Postdecrement FSRn--
Description: This instruction is used to move data
between W and one of the indirect
registers (INDFn). Before/after this
move, the pointer (FSRn) is updated by
pre/post incrementing/decrementing it.
Note: The INDFn registers are not
physical registers. Any instruction that
accesses an INDFn register actually
accesses the register at the address
specified by the FSRn.
FSRn is limited to the range
0000h-FFFFh.
Incrementing/decrementing it beyond
these bounds will cause it to
wrap-around.
The increment/decrement operation on
FSRn WILL NOT affect any Status bits.
NOP No Operation
Syntax: [ label ] NOP
Operands: None
Operation: No operation
Status Affected: None
Description: No operation.
Words: 1
Cycles: 1
Example: NOP
OPTION Load OPTION_REG Register
with W
Syntax: [ label ] OPTION
Operands: None
Operation: (W) OPTION_REG
Status Affected: None
Description: Move data from W register to
OPTION_REG register.
RESET Software Reset
Syntax: [ label ] RESET
Operands: None
Operation: Execute a device Reset. Resets the
nRI flag of the PCON register.
Status Affected: None
Description: This instruction provides a way to
execute a hardware Reset by soft-
ware.
PIC12F/LF1822/16F/LF1823
DS41413A-page 330 Preliminary 2010 Microchip Technology Inc.
RETFIE Return from Interrupt
Syntax: [ label ] RETFIE k
Operands: None
Operation: TOS PC,
1 GIE
Status Affected: None
Description: Return from Interrupt. Stack is POPed
and Top-of-Stack (TOS) is loaded in
the PC. Interrupts are enabled by
setting Global
Interrupt Enable bit, GIE
(INTCON<7>). This is a two-cycle
instruction.
Words: 1
Cycles: 2
Example: RETFIE
After Interrupt
PC = TOS
GIE = 1
RETLW Return with literal in W
Syntax: [ label ] RETLW k
Operands: 0 k 255
Operation: k (W);
TOS PC
Status Affected: None
Description: The W register is loaded with the eight
bit literal ‘k’. The program counter is
loaded from the top of the stack (the
return address). This is a two-cycle
instruction.
Words: 1
Cycles: 2
Example:
TABLE
CALL TABLE;W contains table
;offset value
• ;W now has table value
•
•
ADDWF PC ;W = offset
RETLW k1 ;Begin table
RETLW k2 ;
•
•
•
RETLW kn ; End of table
Before Instruction
W = 0x07
After Instruction
W = value of k8
RETURN Return from Subroutine
Syntax: [ label ] RETURN
Operands: None
Operation: TOS PC
Status Affected: None
Description: Return from subroutine. The stack is
POPed and the top of the stack (TOS)
is loaded into the program counter.
This is a two-cycle instruction.
RLF Rotate Left f through Carry
Syntax: [ label ] RLF f,d
Operands: 0 f 127
d [0,1]
Operation: See description below
Status Affected: C
Description: The contents of register ‘f’ are rotated
one bit to the left through the Carry
flag. If ‘d’ is ‘0’, the result is placed in
the W register. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
Words: 1
Cycles: 1
Example: RLF REG1,0
Before Instruction
REG1 = 1110 0110
C=0
After Instruction
REG1 = 1110 0110
W = 1100 1100
C=1
Register fC
2010 Microchip Technology Inc. Preliminary DS41413A-page 331
PIC12F/LF1822/16F/LF1823
RRF Rotate Right f through Carry
Syntax: [ label ] RRF f,d
Operands: 0 f 127
d [0,1]
Operation: See description below
Status Affected: C
Description: The contents of register ‘f’ are rotated
one bit to the right through the Carry
flag. If ‘d’ is ‘0’, the result is placed in
the W register. If ‘d’ is ‘1’, the result is
placed back in register ‘f’.
SLEEP Enter Sleep mode
Syntax: [ label ]SLEEP
Operands: None
Operation: 00h WDT,
0 WDT prescaler,
1 TO,
0 PD
Status Affected: TO, PD
Description: The power-down Status bit, PD is
cleared. Time-out Status bit, TO is
set. Watchdog Timer and its pres-
caler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.
Register fC
SUBLW Subtract W from literal
Syntax: [ label ]SUBLW k
Operands: 0 k 255
Operation: k - (W) W)
Status Affected: C, DC, Z
Description: The W register is subtracted (2’s com-
plement method) from the eight-bit
literal ‘k’. The result is placed in the W
register.
SUBWF Subtract W from f
Syntax: [ label ] SUBWF f,d
Operands: 0 f 127
d [0,1]
Operation: (f) - (W) destination)
Status Affected: C, DC, Z
Description: Subtract (2’s complement method) W
register from register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W
register. If ‘d’ is ‘1’, the result is stored
back in register ‘f.
SUBWFB Subtract W from f with Borrow
Syntax: SUBWFB f {,d}
Operands: 0 f 127
d [0,1]
Operation: (f) – (W) – (B) dest
Status Affected: C, DC, Z
Description: Subtract W and the BORROW flag
(CARRY) from register ‘f’ (2’s comple-
ment method). If ‘d’ is ‘0’, the result is
stored in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’.
C = 0W k
C = 1W k
DC = 0W<3:0> k<3:0>
DC = 1W<3:0> k<3:0>
C = 0W f
C = 1W f
DC = 0W<3:0> f<3:0>
DC = 1W<3:0> f<3:0>
PIC12F/LF1822/16F/LF1823
DS41413A-page 332 Preliminary 2010 Microchip Technology Inc.
SWAPF Swap Nibbles in f
Syntax: [ label ] SWAPF f,d
Operands: 0 f 127
d [0,1]
Operation: (f<3:0>) (destination<7:4>),
(f<7:4>) (destination<3:0>)
Status Affected: None
Description: The upper and lower nibbles of regis-
ter ‘f’ are exchanged. If ‘d’ is ‘0’, the
result is placed in the W register. If ‘d’
is ‘1’, the result is placed in register ‘f’.
TRIS Load TRIS Register with W
Syntax: [ label ] TRIS f
Operands: 5 f 7
Operation: (W) TRIS register ‘f’
Status Affected: None
Description: Move data from W register to TRIS
register.
When ‘f’ = 5, TRISA is loaded.
When ‘f’ = 6, TRISB is loaded.
When ‘f’ = 7, TRISC is loaded.
XORLW Exclusive OR literal with W
Syntax: [ label ] XORLW k
Operands: 0 k 255
Operation: (W) .XOR. k W)
Status Affected: Z
Description: The contents of the W register are
XOR’ed with the eight-bit
literal ‘k’. The result is placed in the
W register.
XORWF Exclusive OR W with f
Syntax: [ label ] XORWF f,d
Operands: 0 f 127
d [0,1]
Operation: (W) .XOR. (f) destination)
Status Affected: Z
Description: Exclusive OR the contents of the W
register with register ‘f’. If ‘d’ is ‘0’, the
result is stored in the W register. If ‘d’
is ‘1’, the result is stored back in regis-
ter ‘f’.
2010 Microchip Technology Inc. Preliminary DS41413A-page 333
PIC12F/LF1822/16F/LF1823
29.0 ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings(†)
Ambient temperature under bias....................................................................................................... -40°C to +125°C
Storage temperature ........................................................................................................................ -65°C to +150°C
Voltage on VDD with respect to VSS, PIC12F1822/16F1823 .............................................................. -0.3V to +6.5V
Voltage on VDD with respect to VSS, PIC12LF1822/16LF1823 .......................................................... -0.3V to +4.0V
Voltage on MCLR with respect to Vss ................................................................................................. -0.3V to +9.0V
Voltage on all other pins with respect to VSS ........................................................................... -0.3V to (VDD + 0.3V)
Total power dissipation(1) ............................................................................................................................... 800 mW
Maximum current out of VSS pin, -40°C TA +85°C for industrial................................................................. 85 mA
Maximum current out of VSS pin, -40°C TA +125°C for extended .............................................................. 35 mA
Maximum current into VDD pin, -40°C TA +85°C for industrial.................................................................. 800 mA
Maximum current into VDD pin, -40°C TA +125°C for extended ................................................................. 30 mA
Clamp current, IK (VPIN < 0 or VPIN > VDD)20 mA
Maximum output current sunk by any I/O pin.................................................................................................... 25 mA
Maximum output current sourced by any I/O pin .............................................................................................. 25 mA
Note 1: Power dissipation is calculated as follows: PDIS = VDD x {IDD – IOH} + {(VDD – VOH) x IOH} + (VOl x IOL).
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the
device. This is a stress rating only and functional operation of the device at those or any other conditions above those
indicated in the operation listings of this specification is not implied. Exposure above maximum rating conditions for
extended periods may affect device reliability.
PIC12F/LF1822/16F/LF1823
DS41413A-page 334 Preliminary 2010 Microchip Technology Inc.
FIGURE 29-1: PIC12F1822/16F1823 VOLTAGE FREQUENCY GRAPH, -40°C
TA
+125°C
FIGURE 29-2: PIC12LF1822/16LF1823 VOLTAGE FREQUENCY GRAPH, -40°C
TA
+125°C
1.8
2.5
2.0
0
2.3
Frequency (MHz)
VDD (V)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
2: Refer to Table 29-1 for each Oscillator mode’s supported frequencies.
43210 16
5.5
3.6
1.8
2.5
2.0
0
2.3
Frequency (MHz)
VDD (V)
Note 1: The shaded region indicates the permissible combinations of voltage and frequency.
2: Refer to Table 29-1 for each Oscillator mode’s supported frequencies.
432
10 16
3.6
2010 Microchip Technology Inc. Preliminary DS41413A-page 335
PIC12F/LF1822/16F/LF1823
FIGURE 29-3: HFINTOSC FREQUENCY ACCURACY OVER DEVICE VDD AND TEMPERATURE
125
25
2.0
0
60
85
VDD (V)
4.0 5.04.5
Temperature (°C)
2.5 3.0 3.5 5.51.8
-40
-20
± 5%
± 2%
± 5%
± 2.5%
PIC12F/LF1822/16F/LF1823
DS41413A-page 336 Preliminary 2010 Microchip Technology Inc.
29.1 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Industrial, Extended)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param.
No.
Sym. Characteristic Min. Typ† Max. Units Conditions
D001 VDD Supply Voltage
PIC12LF1822/16LF1823 1.8
2.3
—
—
3.6
3.6
V
V
FOSC 16 MHz:
FOSC 32 MHz (NOTE 2)
D001 PIC12F1822/16F1823 1.8
2.3
—
—
5.5
5.5
V
V
FOSC 16 MHz:
FOSC 32 MHz (NOTE 2)
D002* VDR RAM Data Retention Voltage(1)
PIC12LF1822/16LF1823 1.5 — — V Device in Sleep mode
D002* PIC12F1822/16F1823 1.7 — — V Device in Sleep mode
VPOR*Power-on Reset Release Voltage —1.6— V
VPORR*Power-on Reset Rearm Voltage
PIC12LF1822/16LF1823 — 0.8 — V Device in Sleep mode
PIC12F1822/16F1823 —1.7 — V Device in Sleep mode
D003 VADFVR Fixed Voltage Reference Voltage for
ADC, Initial Accuracy
-5.5
-6.0
-5.5
-6.0
-5.5
-6.0
5.5
6
5.5
6
5.5
6
% 1.024V, VDD 2.5V, 85°C
1.024V, VDD 2.5V, 125°C
2.048V, VDD 2.5V, 85°C
2.048V, VDD 2.5V, 125°C
4.096V, VDD 4.75V, 85°C
4.096V, VDD 4.75V, 125°C
VCDAFVR Fixed Voltage Reference Voltage for
Comparator and DAC, Initial Accu-
racy
-5.5
-6.0
-5.5
-6.0
-5.5
-6.0
5.5
6
5.5
6
5.5
6
% 1.024V, VDD 2.5V, 85°C
1.024V, VDD 2.5V, 125°C
2.048V, VDD 2.5V, 85°C
2.048V, VDD 2.5V, 125°C
4.096V, VDD 4.75V, 85°C
4.096V, VDD 4.75V, 125°C
D004* SVDD VDD Rise Rate to ensure internal
Power-on Reset signal
0.05 — — V/ms See Section 7.1 “Power-on Reset
(POR)” for details.
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data.
2: PLL required for 32 MHz operation.
2010 Microchip Technology Inc. Preliminary DS41413A-page 337
PIC12F/LF1822/16F/LF1823
FIGURE 29-4: POR AND POR REARM WITH SLOW RISING VDD
VDD
VPOR
VPORR
VSS
VSS
NPOR
TPOR(3)
POR REARM
Note 1: When NPOR is low, the device is held in Reset.
2: TPOR 1 s typical.
3: TVLOW 2.7 s typical.
TVLOW(2)
PIC12F/LF1822/16F/LF1823
DS41413A-page 338 Preliminary 2010 Microchip Technology Inc.
29.2 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Industrial, Extended)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No.
Device
Characteristics Min. Typ† Max. Units
Conditions
VDD Note
Supply Current (IDD)(1, 2)
D010 — 8.0 —A1.8
FOSC = 32 kHz
LP Oscillator mode
— 12.0 —A3.0
D010 —23 —A1.8 FOSC = 32 kHz
LP Oscillator mode
—28 —A3.0
—33 —A5.0
D011 — 60 —A1.8F
OSC = 1 MHz
XT Oscillator mode
—110 —A3.0
D011 —82 —A1.8 FOSC = 1 MHz
XT Oscillator mode
—141 —A3.0
—200 —A5.0
D012 — 145 —A1.8F
OSC = 4 MHz
XT Oscillator mode
— 260 —A3.0
D012 —165 —A1.8 FOSC = 4 MHz
XT Oscillator mode
—290 —A3.0
—368 —A5.0
D013 — 34 —A1.8F
OSC = 1 MHz
EC Oscillator mode, Medium-power mode
—59 —A3.0
D013 —60 —A1.8 FOSC = 1 MHz
EC Oscillator mode
Medium-power mode
—92 —A3.0
—126 —A5.0
D014 — 118 —A1.8F
OSC = 4 MHz
EC Oscillator mode,
Medium-power mode
— 210 —A3.0
D014 —143 —A1.8 FOSC = 4 MHz
EC Oscillator mode
Medium-power mode
—240 —A3.0
—300 —A5.0
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from
rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading
and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current
consumption.
3: 8 MHz internal RC oscillator with 4x PLL enabled.
4: 8 MHz crystal oscillator with 4x PLL enabled.
5: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended
by the formula IR = VDD/2REXT (mA) with REXT in k.
2010 Microchip Technology Inc. Preliminary DS41413A-page 339
PIC12F/LF1822/16F/LF1823
Supply Current (IDD)(1, 2)
D015 — 2.0 —A1.8FOSC = 31 kHz
LFINTOSC mode
—4.0 —A3.0
D015 —18 —A1.8 FOSC = 31 kHz
LFINTOSC mode
—24 —A3.0
—25 —A5.0
D016 — 110 —A1.8F
OSC = 500 kHz
MFINTOSC mode
— 150 —A3.0
D016 —150 —A1.8 FOSC = 500 kHz
MFINTOSC mode
—210 —A3.0
—270 —A5.0
D017* — .25 —mA 1.8 FOSC = 8 MHz
HFINTOSC mode
—.45 —mA 3.0
D017* —.35 —mA 1.8 FOSC = 8 MHz
HFINTOSC mode
—.55 —mA 3.0
—.75 —mA 5.0
D018 — .47 —mA 1.8 FOSC = 16 MHz
HFINTOSC mode
—.84 —mA 3.0
D018 —.7 —mA 1.8 FOSC = 16 MHz
HFINTOSC mode
—1.0 —mA 3.0
—1.4 —mA 5.0
D019 — 1.6 —mA 3.0 FOSC = 32 MHz
HFINTOSC mode (Note 3)
—1.8 —mA 3.6
D019 —1.6 —mA 3.0 FOSC = 32 MHz
HFINTOSC mode (Note 3)
—1.8 —mA 5.0
29.2 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Industrial, Extended)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No.
Device
Characteristics Min. Typ† Max. Units
Conditions
VDD Note
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from
rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading
and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current
consumption.
3: 8 MHz internal RC oscillator with 4x PLL enabled.
4: 8 MHz crystal oscillator with 4x PLL enabled.
5: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended
by the formula IR = VDD/2REXT (mA) with REXT in k.
PIC12F/LF1822/16F/LF1823
DS41413A-page 340 Preliminary 2010 Microchip Technology Inc.
Supply Current (IDD)(1, 2)
D020 — 1.3 —mA 3.0 FOSC = 32 MHz
HS Oscillator mode (Note 4)
—1.6 —mA 3.6
D020 —3.3 —mA 3.0 FOSC = 32 MHz
HS Oscillator mode (Note 4)
—3.8 —mA 5.0
D021 — 300 —A1.8F
OSC = 4 MHz
EXTRC mode (Note 5)
— 500 —A3.0
D021 —350 —A1.8 FOSC = 4 MHz
EXTRC mode (Note 5)
—550 —A3.0
—620 —A5.0
29.2 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Industrial, Extended)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No.
Device
Characteristics Min. Typ† Max. Units
Conditions
VDD Note
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from
rail-to-rail; all I/O pins tri-stated, pulled to VDD; MCLR = VDD; WDT disabled.
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading
and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current
consumption.
3: 8 MHz internal RC oscillator with 4x PLL enabled.
4: 8 MHz crystal oscillator with 4x PLL enabled.
5: For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended
by the formula IR = VDD/2REXT (mA) with REXT in k.
2010 Microchip Technology Inc. Preliminary DS41413A-page 341
PIC12F/LF1822/16F/LF1823
29.3 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Power-Down)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No. Device Characteristics Min. Typ† Max.
+85°C
Max.
+125°C Units
Conditions
VDD Note
Power-down Base Current (IPD)(2)
D022 — 0.02 — — A 1.8 WDT, BOR, FVR, and T1OSC
disabled, all Peripherals Inactive
—0.03 — — A3.0
D022 —14 — — A1.8 WDT, BOR, FVR, and T1OSC
disabled, all Peripherals Inactive
—14.5 — — A3.0
—15.5 — — A5.0
D023 — 0.3 — — A 1.8 LPWDT Current (Note 1)
—0.75 — — A3.0
D023 —14 — — A1.8 LPWDT Current (Note 1)
—17 — — A3.0
—18 — — A5.0
D023A — 8.5 — — A 1.8 FVR current (Note 1)
—8.5 — — A3.0
D023A —32 — — A1.8 FVR current (Note 1)
—38 — — A3.0
—68 — — mA 5.0
D024 — 8.0 — — A 3.0 BOR Current (Note 1)
D024 —30 — — A3.0 BOR Current (Note 1)
—33 — — A5.0
D025 — 0.6 — — A 1.8 T1OSC Current (Note 1)
—1.8 — — A3.0
D025 —3.0 — — A1.8 T1OSC Current (Note 1)
—3.5 — — A3.0
—4.0 — — A5.0
D026 — 0.1 — — A 1.8 A/D Current (Note 1, Note 3), no
conversion in progress
—0.1 — — A3.0
D026 —15 — — A1.8 A/D Current (Note 1, Note 3), no
conversion in progress
—20 — — A3.0
—24 — — A5.0
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is
enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max
values should be used when calculating total current consumption.
2: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
3: A/D oscillator source is FRC.
PIC12F/LF1822/16F/LF1823
DS41413A-page 342 Preliminary 2010 Microchip Technology Inc.
Power-down Base Current (IPD)(2)
D026A* — 250 — — A 1.8 A/D Current (Note 1, Note 3),
conversion in progress
—250 — — A3.0
D026A* —280 — — A1.8 A/D Current (Note 1, Note 3),
conversion in progress
—280 — — A3.0
—280 — — A5.0
D027 — 2.9 — — A 1.8 Cap Sense Low Power
Oscillator mode (Note 1)
—3.8 — — A3.0
D027 —15 — — A1.8 Cap Sense Low Power
Oscillator mode (Note 1)
—19 — — A3.0
—20 — — A5.0
D027A — 6.3 — — A 1.8 Cap Sense Medium Power
Oscillator mode (Note 1)
—7.9 — — A3.0
D027A —20 — — A1.8 Cap Sense Medium Power
Oscillator mode (Note 1)
—22 — — A3.0
—23 — — A5.0
D027B — 16 — — A 1.8 Cap Sense High Power
Oscillator mode (Note 1)
—41 — — A3.0
D027B —28 — — A1.8 Cap Sense High Power
Oscillator mode (Note 1)
—52 — — A3.0
—60 — — A5.0
D028 — 7.3 — — A 1.8 Comparator Current, Low Power
mode, one comparator enabled
(Note 1)
—7.4 — — A3.0
D028 —19 — — A1.8 Comparator Current, Low Power
mode, one comparator enabled
(Note 1)
—20 — — A3.0
—21 — — A5.0
D028A — 7.5 — — A 1.8 Comparator Current, Low Power
mode, two comparators enabled
(Note 1)
—7.6 — — A3.0
D028A —20 — — A1.8 Comparator Current, Low Power
mode, two comparators enabled
(Note 1)
—21 — — A3.0
—22 — — A5.0
29.3 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Power-Down) (Continued)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No. Device Characteristics Min. Typ† Max.
+85°C
Max.
+125°C Units
Conditions
VDD Note
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is
enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max
values should be used when calculating total current consumption.
2: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
3: A/D oscillator source is FRC.
2010 Microchip Technology Inc. Preliminary DS41413A-page 343
PIC12F/LF1822/16F/LF1823
Power-down Base Current (IPD)(2)
D028B — 46 — — A 1.8 Comparator Current, High Power
mode, one comparator enabled
(Note 1)
—47 — — A3.0
D028B —60 — — A1.8 Comparator Current, High Power
mode, one comparator enabled
(Note 1)
—62 — — A3.0
—64 — — A5.0
D028C — 47 — — A 1.8 Comparator Current, High Power
mode, two comparators enabled
—48 — — A3.0
D028C —61 — — A1.8 Comparator Current, High Power
mode, two comparators enabled
(Note 1)
—63 — — A3.0
—65 — — A5.0
29.3 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E (Power-Down) (Continued)
PIC12LF1822/16LF1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
PIC12F1822/16F1823
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No. Device Characteristics Min. Typ† Max.
+85°C
Max.
+125°C Units
Conditions
VDD Note
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is
enabled. The peripheral current can be determined by subtracting the base IDD or IPD current from this limit. Max
values should be used when calculating total current consumption.
2: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with
the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD.
3: A/D oscillator source is FRC.
PIC12F/LF1822/16F/LF1823
DS41413A-page 344 Preliminary 2010 Microchip Technology Inc.
29.4 DC Characteristics: PIC12F/LF1822/16F/LF1823-I/E
DC CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
-40°C TA +125°C for extended
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
VIL Input Low Voltage
I/O PORT:
D030 with TTL buffer — — 0.8 V 4.5V VDD 5.5V
D030A — — 0.15 VDD V1.8V VDD 4.5V
D031 with Schmitt Trigger buffer — — 0.2 VDD V2.0V VDD 5.5V
with I2C™ levels — — 0.3 VDD V
with SMBus levels — — 0.8 V 2.7V VDD 5.5V
D032 MCLR, OSC1 (RC mode)(1) ——0.2VDD V
D033 OSC1 (HS mode) — — 0.3 VDD V
VIH Input High Voltage
I/O ports: — —
D040 with TTL buffer 2.0 — — V 4.5V VDD 5.5V
D040A 0.25 VDD +
0.8
——V1.8V VDD 4.5V
D041 with Schmitt Trigger buffer 0.8 VDD ——V2.0V VDD 5.5V
with I2C™ levels 0.7 VDD ——V
with SMBus levels 2.1 — — V 2.7V VDD 5.5V
D042 MCLR 0.8 VDD ——V
D043A OSC1 (HS mode) 0.7 VDD ——V
D043B OSC1 (RC mode) 0.9 VDD ——V(Note 1)
IIL Input Leakage Current(2)
D060 I/O ports — ± 5
± 5
± 125
± 1000
nA
nA
VSS VPIN VDD, Pin at high-
impedance at 85°C
125°C
D061 MCLR(3) —± 50± 200nAVSS VPIN VDD at 85°C
IPUR Weak Pull-up Current
D070* 25
25
100
140
200
300 A
VDD = 3.3V, VPIN = VSS
VDD = 5.0V, VPIN = VSS
VOL Output Low Voltage(4)
D080 I/O ports
——0.6V
IOL = 8mA, VDD = 5V
IOL = 6mA, VDD = 3.3V
IOL = 1.8mA, VDD = 1.8V
VOH Output High Voltage(4)
D090 I/O ports
VDD - 0.7 — — V
IOH = 3.5mA, VDD = 5V
IOH = 3mA, VDD = 3.3V
IOH = 1mA, VDD = 1.8V
Capacitive Loading Specs on Output Pins
D101* COSC2 OSC2 pin — — 15 pF In XT, HS and LP modes when
external clock is used to drive
OSC1
D101A* CIO All I/O pins — — 50 pF
*These parameters are characterized but not tested.
†Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
Note 1: In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external
clock in RC mode.
2: Negative current is defined as current sourced by the pin.
3: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent
normal operating conditions. Higher leakage current may be measured at different input voltages.
4: Including OSC2 in CLKOUT mode.
2010 Microchip Technology Inc. Preliminary DS41413A-page 345
PIC12F/LF1822/16F/LF1823
29.5 Memory Programming Requirements
DC CHARACTERISTICS Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
Program Memory
Programming Specifications
D110 VIHH Voltage on MCLR/VPP/RA5 pin 8.0 — 9.0 V (Note 3, Note 4)
D111 IDDP Supply Current during
Programming
——10mA
D112 VDD for Bulk Erase 2.7 — VDD
max.
V
D113 VPEW VDD for Write or Row Erase VDD
min.
—V
DD
max.
V
D114 IPPPGM Current on MCLR/VPP during Erase/
Write
——1.0mA
D115 IDDPGM Current on VDD during Erase/Write — 5.0 mA
Data EEPROM Memory
D116 EDByte Endurance 100K — — E/W -40C to +85C
D117 VDRW VDD for Read/Write VDD
min.
—V
DD
max.
V
D118 TDEW Erase/Write Cycle Time — 4.0 5.0 ms
D119 TRETD Characteristic Retention 40 — — Year Provided no other
specifications are violated
D120 TREF Number of Total Erase/Write
Cycles before Refresh(2)
1M 10M — E/W -40°C to +85°C
Program Flash Memory
D121 EPCell Endurance 10K — — E/W -40C to +85C (Note 1)
D122 VPR VDD for Read VDD
min.
—V
DD
max.
V
D123 TIW Self-timed Write Cycle Time — 2 2.5 ms
D124 TRETD Characteristic Retention 40 — — Year Provided no other
specifications are violated
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Self-write and Block Erase.
2: Refer to Section 11.2 “Using the Data EEPROM” for a more detailed discussion on data EEPROM
endurance.
3: Required only if single-supply programming is disabled.
4: The MPLAB ICD 2 does not support variable VPP output. Circuitry to limit the ICD 2 VPP voltage must be
placed between the ICD 2 and target system when programming or debugging with the ICD 2.
PIC12F/LF1822/16F/LF1823
DS41413A-page 346 Preliminary 2010 Microchip Technology Inc.
29.6 Thermal Considerations
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +125°C
Param
No. Sym. Characteristic Typ. Units Conditions
TH01 JA Thermal Resistance Junction to Ambient TBD C/W 8-pin PDIP package
TBD C/W 8-pin SOIC package
TBD C/W 8-pin DFN 3X3mm package
TBD C/W 14-pin PDIP package
TBD C/W 14-pin SOIC package
TBD C/W 14-pin TSSOP 4x4mm package
TBD C/W 16-pin QFN 4X4mm package
TH02 JC Thermal Resistance Junction to Case TBD C/W 8-pin PDIP package
TBD C/W 8-pin SOIC package
TBD C/W 8-pin DFN 3X3mm package
TBD C/W 14-pin PDIP package
TBD C/W 14-pin SOIC package
TBD C/W 14-pin TSSOP 4x4mm package
TBD C/W 16-pin QFN 4X4mm package
TH03 TJMAX Maximum Junction Temperature 150 C
TH04 PD Power Dissipation — W PD = PINTERNAL + PI/O
TH05 PINTERNAL Internal Power Dissipation — W PINTERNAL = IDD x VDD(1)
TH06 PI/OI/O Power Dissipation — W PI/O = (IOL * VOL) + (IOH * (VDD - VOH))
TH07 PDER Derated Power — W PDER = PDMAX (TJ - TA)/JA(2)
Legend: TBD = To Be Determined
Note 1: IDD is current to run the chip alone without driving any load on the output pins.
2: TA = Ambient Temperature.
3: TJ = Junction Temperature.
2010 Microchip Technology Inc. Preliminary DS41413A-page 347
PIC12F/LF1822/16F/LF1823
29.7 Timing Parameter Symbology
The timing parameter symbols have been created with
one of the following formats:
FIGURE 29-5: LOAD CONDITIONS
1. TppS2ppS
2. TppS
T
F Frequency T Time
Lowercase letters (pp) and their meanings:
pp
cc CCP1 osc OSC1
ck CLKOUT rd RD
cs CS rw RD or WR
di SDIx sc SCKx
do SDO ss SS
dt Data in t0 T0CKI
io I/O PORT t1 T1CKI
mc MCLR wr WR
Uppercase letters and their meanings:
S
FFall PPeriod
HHigh RRise
I Invalid (High-impedance) V Valid
L Low Z High-impedance
V
SS
C
L
Legend: CL = 50 pF for all pins, 15 pF for
OSC2 output
Load Condition
Pin
PIC12F/LF1822/16F/LF1823
DS41413A-page 348 Preliminary 2010 Microchip Technology Inc.
29.8 AC Characteristics: PIC12F/LF1822/16F/LF1823-I/E
FIGURE 29-6: CLOCK TIMING
TABLE 29-1: CLOCK OSCILLATOR TIMING REQUIREMENTS
OSC1/CLKIN
OSC2/CLKOUT
Q4 Q1 Q2 Q3 Q4 Q1
OS02
OS03
OS04 OS04
OSC2/CLKOUT
(LP,XT,HS Modes)
(CLKOUT Mode)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
OS01 FOSC External CLKIN Frequency(1) DC — 0.5 MHz EC Oscillator mode (low)
DC — 4 MHz EC Oscillator mode (medium)
DC — 32 MHz EC Oscillator mode (high)
Oscillator Frequency(1) — 32.768 — kHz LP Oscillator mode
0.1 — 4 MHz XT Oscillator mode
1 — 4 MHz HS Oscillator mode, VDD 2.3V
1 — 20 MHz HS Oscillator mode, VDD > 2.3V
DC — 4 MHz RC Oscillator mode
OS02 TOSC External CLKIN Period(1) 27 — s LP Oscillator mode
250 — ns XT Oscillator mode
50 — ns HS Oscillator mode
31.25 — ns EC Oscillator mode
Oscillator Period(1) — 30.5 — s LP Oscillator mode
250 — 10,000 ns XT Oscillator mode
50 — 1,000 ns HS Oscillator mode
250 — — ns RC Oscillator mode
OS03 TCY Instruction Cycle Time(1) 125 — DC ns TCY = FOSC/4
OS04* TosH,
TosL
External CLKIN High,
External CLKIN Low
2——s LP oscillator
100 — — ns XT oscillator
20 — — ns HS oscillator
OS05* TosR,
TosF
External CLKIN Rise,
External CLKIN Fall
0—ns LP oscillator
0—ns XT oscillator
0—ns HS oscillator
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: Instruction cycle period (T
CY) equals four times the input oscillator time base period. All specified values are based on
characterization data for that particular oscillator type under standard operating conditions with the device executing code.
Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current con-
sumption. All devices are tested to operate at “min” values with an external clock applied to OSC1 pin. When an external
clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices.
2010 Microchip Technology Inc. Preliminary DS41413A-page 349
PIC12F/LF1822/16F/LF1823
TABLE 29-2: OSCILLATOR PARAMETERS
TABLE 29-3: PLL CLOCK TIMING SPECIFICATIONS (VDD = 2.7V TO 5.5V)
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param
No. Sym. Characteristic Freq.
Tolerance Min. Typ† Max. Units Conditions
OS08 HFOSC Internal Calibrated HFINTOSC
Frequency(2)
2% — 16.0 — MHz 0°C TA +60°C, VDD 2.5V
2.5% — 16.0 — MHz 60°C TA +85°C, VDD 2.5V
5% — 16.0 — MHz -40°C TA +125°C
OS08A MFOSC Internal Calibrated MFINTOSC
Frequency(2)
2% — 500 — kHz 60°C TA +60°C, VDD 2.5V
2.5% — 500 — kHz 0°C TA +85°C, VDD 2.5V
5% — 500 — kHz -40°C TA +125°C
OS10* TIOSC ST HFINTOSC
Wake-up from Sleep Start-up Time
MFINTOSC
Wake-up from Sleep Start-up Time
—
—
—
—
5
20
8
30
s
s
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on
characterization data for that particular oscillator type under standard operating conditions with the device executing code.
Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current con-
sumption. All devices are tested to operate at “min” values with an external clock applied to the OSC1 pin. When an exter-
nal clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices.
2: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 F and 0.01 F values in parallel are recommended.
3: By design.
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
F10 FOSC Oscillator Frequency Range 4 — 8 MHz
F11 FSYS On-Chip VCO System Frequency 16 — 32 MHz
F12 TRC PLL Start-up Time (Lock Time) — — 2 ms
F13* CLK CLKOUT Stability (Jitter) -0.25% — +0.25% %
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3V, 25C unless otherwise stated. These parameters are for design guidance
only and are not tested.
PIC12F/LF1822/16F/LF1823
DS41413A-page 350 Preliminary 2010 Microchip Technology Inc.
FIGURE 29-7: CLKOUT AND I/O TIMING
FOSC
CLKOUT
I/O pin
(Input)
I/O pin
(Output)
Q4 Q1 Q2 Q3
OS11
OS19
OS13
OS15
OS18, OS19
OS20
OS21
OS17
OS16
OS14
OS12
OS18
Old Value New Value
Write Fetch Read ExecuteCycle
2010 Microchip Technology Inc. Preliminary DS41413A-page 351
PIC12F/LF1822/16F/LF1823
TABLE 29-4: CLKOUT AND I/O TIMING PARAMETERS
FIGURE 29-8: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
OS11 TosH2ckL FOSC to CLKOUT (1) ——70nsVDD = 3.3-5.0V
OS12 TosH2ckH FOSC to CLKOUT (1) ——72nsVDD = 3.3-5.0V
OS13 TckL2ioV CLKOUT to Port out valid(1) ——20ns
OS14 TioV2ckH Port input valid before CLKOUT(1) TOSC + 200 ns — — ns
OS15 TosH2ioV Fosc (Q1 cycle) to Port out valid — 50 70* ns VDD = 3.3-5.0V
OS16 TosH2ioI Fosc (Q2 cycle) to Port input invalid
(I/O in hold time)
50 — — ns VDD = 3.3-5.0V
OS17 TioV2osH Port input valid to Fosc(Q2 cycle)
(I/O in setup time)
20 — — ns
OS18 TioR Port output rise time(2) —
—
40
15
72
32
ns VDD = 1.8V
VDD = 3.3-5.0V
OS19 TioF Port output fall time(2) —
—
28
15
55
30
ns VDD = 1.8V
VDD = 3.3-5.0V
OS20* Tinp INT pin input high or low time 25 — — ns
OS21* Tioc Interrupt-on-change new input level
time
25 — — ns
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25C unless otherwise stated.
Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC.
2: Includes OSC2 in CLKOUT mode.
VDD
MCLR
Internal
POR
PWRT
Time-out
OSC
Start-Up Time
Internal Reset(1)
Watchdog Timer
33
32
30
31
34
I/O pins
34
Note 1: Asserted low.
Reset(1)
PIC12F/LF1822/16F/LF1823
DS41413A-page 352 Preliminary 2010 Microchip Technology Inc.
FIGURE 29-9: BROWN-OUT RESET TIMING AND CHARACTERISTICS
VBOR
VDD
(Device in Brown-out Reset) (Device not in Brown-out Reset)
33(1)
Note 1: 64 ms delay only if PWRTE bit in the Configuration Word 1 is programmed to ‘0’.
2 ms delay if PWRTE = 0 and VREGEN = 1.
Reset
(due to BOR)
VBOR and VHYST
37
2010 Microchip Technology Inc. Preliminary DS41413A-page 353
PIC12F/LF1822/16F/LF1823
TABLE 29-5: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET PARAMETERS
FIGURE 29-10: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
30 TMCLMCLR Pulse Width (low) 2
5
—
—
—
—
s
s
VDD = 3.3-5V, -40°C to +85°C
VDD = 3.3-5V
31 TWDTLP Low-Power Watchdog Timer
Time-out Period (No Prescaler)
10 18 27 ms VDD = 3.3V-5V
32 TOST Oscillator Start-up Timer Period(1), (2) — 1024 — Tosc (Note 3)
33* TPWRT Power-up Timer Period, PWRTE =040 65 140 ms
34* TIOZ I/O high-impedance from MCLR Low
or Watchdog Timer Reset
——2.0s
35 VBOR Brown-out Reset Voltage 2.38
1.80
2.5
1.9
2.65
2.05
VBORV=2.5V
BORV=1.9V
36* VHYST Brown-out Reset Hysteresis 0 25 50 mV -40°C to +85°C
37* TBORDC Brown-out Reset DC Response
Time
135sVDD VBOR
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are
based on characterization data for that particular oscillator type under standard operating conditions with the
device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or
higher than expected current consumption. All devices are tested to operate at “min” values with an external
clock applied to the OSC1 pin. When an external clock input is used, the “max” cycle time limit is “DC” (no
clock) for all devices.
2: By design.
3: Period of the slower clock.
4: To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the device as
possible. 0.1 F and 0.01 F values in parallel are recommended.
T0CKI
T1CKI
40 41
42
45 46
47 49
TMR0 or
TMR1
PIC12F/LF1822/16F/LF1823
DS41413A-page 354 Preliminary 2010 Microchip Technology Inc.
TABLE 29-6: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
FIGURE 29-11: CAPTURE/COMPARE/PWM TIMINGS (CCP)
TABLE 29-7: CAPTURE/COMPARE/PWM REQUIREMENTS (CCP)
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
40* TT0H T0CKI High Pulse Width No Prescaler 0.5 TCY + 20 — — ns
With Prescaler 10 — — ns
41* TT0L T0CKI Low Pulse Width No Prescaler 0.5 TCY + 20 — — ns
With Prescaler 10 — — ns
42* TT0P T0CKI Period Greater of:
20 or TCY + 40
N
— — ns N = prescale value
(2, 4, ..., 256)
45* TT1H T1CKI High
Time
Synchronous, No Prescaler 0.5 TCY + 20 — — ns
Synchronous,
with Prescaler
15 — — ns
Asynchronous 30 — — ns
46* TT1L T1CKI Low
Time
Synchronous, No Prescaler 0.5 TCY + 20 — — ns
Synchronous, with Prescaler 15 — — ns
Asynchronous 30 — — ns
47* TT1P T1CKI Input
Period
Synchronous Greater of:
30 or TCY + 40
N
— — ns N = prescale value
(1, 2, 4, 8)
Asynchronous 60 — — ns
48 FT1 Timer1 Oscillator Input Frequency Range
(oscillator enabled by setting bit T1OSCEN)
32.4 32.768 33.1 kHz
49* TCKEZTMR1 Delay from External Clock Edge to Timer
Increment
2 TOSC —7 TOSC — Timers in Sync
mode
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
CC01* TccL CCP Input Low Time No Prescaler 0.5TCY + 20 — — ns
With Prescaler 20 — — ns
CC02* TccH CCP Input High Time No Prescaler 0.5TCY + 20 — — ns
With Prescaler 20 — — ns
CC03* TccP CCP Input Period 3TCY + 40
N
— — ns N = prescale value (1, 4 or 16)
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note: Refer to Figure 29-5 for load conditions.
(Capture mode)
CC01 CC02
CC03
CCP
2010 Microchip Technology Inc. Preliminary DS41413A-page 355
PIC12F/LF1822/16F/LF1823
TABLE 29-8: PIC12F/LF1822/16F/LF1823 A/D CONVERTER (ADC) CHARACTERISTICS:
TABLE 29-9: PIC12F/LF1822/16F/LF1823 A/D CONVERSION REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
AD01 NRResolution — — 10 bit
AD02 EIL Integral Error — — ±1.7 LSb VREF = 3.0V
AD03 EDL Differential Error — — ±1 LSb No missing codes
VREF = 3.0V
AD04 EOFF Offset Error — — ±2 LSb VREF = 3.0V
AD05 EGN Gain Error — — ±1.5 LSb VREF = 3.0V
AD06 VREF Reference Voltage(3) 1.8 — VDD V
AD07 VAIN Full-Scale Range VSS —VREF V
AD08 ZAIN Recommended Impedance of
Analog Voltage Source
—— 50kCan go higher if external 0.01F capacitor is
present on input pin.
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: Total Absolute Error includes integral, differential, offset and gain errors.
2: The A/D conversion result never decreases with an increase in the input voltage and has no missing codes.
3: ADC VREF is from external VREF, VDD pin or FVREF, whichever is selected as reference input.
4: When ADC is off, it will not consume any current other than leakage current. The power-down current specification
includes any such leakage from the ADC module.
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
AD130* TAD A/D Clock Period 1.0 — 9.0 sTOSC-based
A/D Internal RC Oscillator
Period
1.0 1.6 6.0 s ADCS<1:0> = 11 (ADRC mode)
AD131 TCNV Conversion Time (not including
Acquisition Time)(1)
—11—TAD Set GO/DONE bit to conversion
complete
AD132* TACQ Acquisition Time — 5.0 — s
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
Note 1: The ADRES register may be read on the following TCY cycle.
PIC12F/LF1822/16F/LF1823
DS41413A-page 356 Preliminary 2010 Microchip Technology Inc.
FIGURE 29-12: PIC12F/LF1822/16F/LF1823 A/D CONVERSION TIMING (NORMAL MODE)
FIGURE 29-13: PIC12F/LF1822/16F/LF1823 A/D CONVERSION TIMING (SLEEP MODE)
AD131
AD130
BSF ADCON0, GO
Q4
A/D CLK
A/D Data
ADRES
ADIF
GO
Sample
OLD_DATA
Sampling Stopped
DONE
NEW_DATA
765 3210
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
1 TCY
4
AD134 (TOSC/2(1))
1 TCY
AD132
AD132
AD131
AD130
BSF ADCON0, GO
Q4
A/D CLK
A/D Data
ADRES
ADIF
GO
Sample
OLD_DATA
Sampling Stopped
DONE
NEW_DATA
7 5 3210
Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the
SLEEP instruction to be executed.
AD134
4
6
1 TCY
(TOSC/2 + TCY(1))
1 TCY
2010 Microchip Technology Inc. Preliminary DS41413A-page 357
PIC12F/LF1822/16F/LF1823
TABLE 29-10: COMPARATOR SPECIFICATIONS
TABLE 29-11: DIGITAL-TO-ANALOG CONVERTER (DAC) SPECIFICATIONS
TABLE 29-12: PIC12F/LF1822/16F/LF1823 LOW DROPOUT (LDO) REGULATOR
CHARACTERISTICS:
Operating Conditions: 1.8V < VDD < 5.5V, -40°C < TA < +125°C (unless otherwise stated).
Param
No. Sym. Characteristics Min. Typ. Max. Units Comments
CM01 VIOFF Input Offset Voltage — ±7.5 ±60 mV
CM02 VICM Input Common Mode Voltage 0 — VDD V
CM03 CMRR Common Mode Rejection Ratio — 50 — dB
CM04 TRESP Response Time — 150 400 ns Note 1
CM05 TMC2OV Comparator Mode Change to
Output Valid*
——10s
CM06 CHYSTER Comparator Hysteresis — 65 — mV
* These parameters are characterized but not tested.
Note 1: Response time measured with one comparator input at VDD/2, while the other input transitions
from VSS to VDD.
Operating Conditions: 1.8V < VDD < 5.5V, -40°C < TA < +125°C (unless otherwise stated).
Param
No. Sym. Characteristics Min. Typ. Max. Units Comments
DAC01* CLSB Step Size(2) —VDD/32 — V
DAC02* CACC Absolute Accuracy — — 1/2 LSb
DAC03* CRUnit Resistor Value (R) — TBD —
DAC04* CST Settling Time(1) ——10s
* These parameters are characterized but not tested.
Legend: TBD = To Be Determined
Note 1: Settling time measured while DACR<4:0> transitions from ‘0000’ to ‘1111’.
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +125°C
Param
No. Sym. Characteristic Min. Typ† Max. Units Conditions
LD001 LDO Regulation Voltage — 3.2 — V
LD002 LDO External Capacitor 0.1 — 1 F
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not
tested.
PIC12F/LF1822/16F/LF1823
DS41413A-page 358 Preliminary 2010 Microchip Technology Inc.
FIGURE 29-14: USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
TABLE 29-13: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS
FIGURE 29-15: USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
TABLE 29-14: USART SYNCHRONOUS RECEIVE REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param.
No. Symbol Characteristic Min. Max. Units Conditions
US120 TCKH2DTV SYNC XMIT (Master and Slave)
Clock high to data-out valid
3.0-5.5V — 80 ns
1.8-5.5V — 100 ns
US121 TCKRF Clock out rise time and fall time
(Master mode)
3.0-5.5V — 45 ns
1.8-5.5V — 50 ns
US122 TDTRF Data-out rise time and fall time 3.0-5.5V — 45 ns
1.8-5.5V — 50 ns
Standard Operating Conditions (unless otherwise stated)
Operating Temperature -40°C TA +125°C
Param.
No. Symbol Characteristic Min. Max. Units Conditions
US125 TDTV2CKL SYNC RCV (Master and Slave)
Data-hold before CK (DT hold time) 10 — ns
US126 T
CKL2DTL Data-hold after CK (DT hold time) 15 — ns
Note: Refer to Figure 29-5 for load conditions.
US121 US121
US120 US122
CK
DT
Note: Refer to Figure 29-5 for load conditions.
US125
US126
CK
DT
2010 Microchip Technology Inc. Preliminary DS41413A-page 359
PIC12F/LF1822/16F/LF1823
FIGURE 29-16: SPI MASTER MODE TIMING (CKE = 0, SMP = 0)
FIGURE 29-17: SPI MASTER MODE TIMING (CKE = 1, SMP = 1)
SSx
SCKx
(CKP = 0)
SCKx
(CKP = 1)
SDOx
SDIx
SP70
SP71 SP72
SP73
SP74
SP75, SP76
SP78
SP79
SP80
SP79
SP78
MSb LSb
bit 6 - - - - - -1
MSb In LSb In
bit 6 - - - -1
Note: Refer to Figure 29-5 for load conditions.
SSx
SCKx
(CKP = 0)
SCKx
(CKP = 1)
SDOx
SDIx
SP81
SP71 SP72
SP74
SP75, SP76
SP78
SP80
MSb
SP79
SP73
MSb In
bit 6 - - - - - -1
LSb In
bit 6 - - - -1
LSb
Note: Refer to Figure 29-5 for load conditions.
PIC12F/LF1822/16F/LF1823
DS41413A-page 360 Preliminary 2010 Microchip Technology Inc.
FIGURE 29-18: SPI SLAVE MODE TIMING (CKE = 0)
FIGURE 29-19: SPI SLAVE MODE TIMING (CKE = 1)
SSx
SCKx
(CKP = 0)
SCKx
(CKP = 1)
SDOx
SDIx
SP70
SP71 SP72
SP73
SP74
SP75, SP76 SP77
SP78
SP79
SP80
SP79
SP78
MSb LSb
bit 6 - - - - - -1
MSb In bit 6 - - - -1 LSb In
SP83
Note: Refer to Figure 29-5 for load conditions.
SSx
SCKx
(CKP = 0)
SCKx
(CKP = 1)
SDOx
SDIx
SP70
SP71 SP72
SP82
SP74
SP75, SP76
MSb bit 6 - - - - - -1 LSb
SP77
MSb In bit 6 - - - -1 LSb In
SP80
SP83
Note: Refer to Figure 29-5 for load conditions.
2010 Microchip Technology Inc. Preliminary DS41413A-page 361
PIC12F/LF1822/16F/LF1823
TABLE 29-15: SPI MODE REQUIREMENTS
FIGURE 29-20: I2C™ BUS START/STOP BITS TIMING
Param
No. Symbol Characteristic Min. Typ† Max. Units Conditions
SP70* TSSL2SCH,
TSSL2SCL
SSx to SCKx or SCKx input TCY ——ns
SP71* TSCH SCKx input high time (Slave mode) TCY + 20 — — ns
SP72* TSCL SCKx input low time (Slave mode) TCY + 20 — — ns
SP73* TDIV2SCH,
TDIV2SCL
Setup time of SDIx data input to SCKx edge 100 — — ns
SP74* TSCH2DIL,
TSCL2DIL
Hold time of SDIx data input to SCKx edge 100 — — ns
SP75* TDOR SDO data output rise time 3.0-5.5V — 10 25 ns
1.8-5.5V — 25 50 ns
SP76* TDOF SDOx data output fall time — 10 25 ns
SP77* TSSH2DOZ SSx to SDOx output high-impedance 10 — 50 ns
SP78* TSCR SCKx output rise time
(Master mode)
3.0-5.5V — 10 25 ns
1.8-5.5V — 25 50 ns
SP79* TSCF SCKx output fall time (Master mode) — 10 25 ns
SP80* TSCH2DOV,
TSCL2DOV
SDOx data output valid after
SCKx edge
3.0-5.5V — — 50 ns
1.8-5.5V — — 145 ns
SP81* TDOV2SCH,
TDOV2SCL
SDOx data output setup to SCKx edge Tcy — — ns
SP82* TSSL2DOV SDOx data output valid after SS edge — — 50 ns
SP83* TSCH2SSH,
TSCL2SSH
SSx after SCKx edge 1.5TCY + 40 — — ns
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note: Refer to Figure 29-5 for load conditions.
SP91
SP92
SP93
SCLx
SDAx
Start
Condition
Stop
Condition
SP90
2010 Microchip Technology Inc. Preliminary DS41413A-page 363
PIC12F/LF1822/16F/LF1823
TABLE 29-16: I2C™ BUS DATA REQUIREMENTS
Param.
No. Symbol Characteristic Min. Max. Units Conditions
SP100* THIGH Clock high time 100 kHz mode 4.0 — s Device must operate at a
minimum of 1.5 MHz
400 kHz mode 0.6 — s Device must operate at a
minimum of 10 MHz
SSPx module 1.5TCY ——
SP101* TLOW Clock low time 100 kHz mode 4.7 — s Device must operate at a
minimum of 1.5 MHz
400 kHz mode 1.3 — s Device must operate at a
minimum of 10 MHz
SSPx module 1.5TCY ——
SP102* TRSDAx and SCLx
rise time
100 kHz mode — 1000 ns
400 kHz mode 20 + 0.1CB300 ns CB is specified to be from
10-400 pF
SP103* TFSDAx and SCLx fall
time
100 kHz mode — 250 ns
400 kHz mode 20 + 0.1CB250 ns CB is specified to be from
10-400 pF
SP106* THD:DAT Data input hold time 100 kHz mode 0 — ns
400 kHz mode 0 0.9 s
SP107* TSU:DAT Data input setup
time
100 kHz mode 250 — ns (Note 2)
400 kHz mode 100 — ns
SP109* TAA Output valid from
clock
100 kHz mode — 3500 ns (Note 1)
400 kHz mode — — ns
SP110* TBUF Bus free time 100 kHz mode 4.7 — s Time the bus must be free
before a new transmission
can start
400 kHz mode 1.3 — s
SP111 CBBus capacitive loading — 400 pF
* These parameters are characterized but not tested.
Note 1: As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region
(min. 300 ns) of the falling edge of SCLx to avoid unintended generation of Start or Stop conditions.
2: A Fast mode (400 kHz) I2C™ bus device can be used in a Standard mode (100 kHz) I2C bus system, but
the requirement T
SU:DAT 250 ns must then be met. This will automatically be the case if the device does
not stretch the low period of the SCLx signal. If such a device does stretch the low period of the SCLx sig-
nal, it must output the next data bit to the SDAx line TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according
to the Standard mode I2C bus specification), before the SCLx line is released.
PIC12F/LF1822/16F/LF1823
DS41413A-page 364 Preliminary 2010 Microchip Technology Inc.
TABLE 29-17: CAP SENSE OSCILLATOR SPECIFICATIONS
FIGURE 29-22: CAP SENSE OSCILLATOR
Param.
No. Symbol Characteristic Min. Typ† Max. Units Conditions
CS01 ISRC Current Source High -3 -8 -15 A
Medium -0.8 -1.5 -3 A
Low -0.1 -0.3 -0.4 A
CS02 ISNK Current Sink High 2.5 7.5 14 A
Medium 0.6 1.5 2.9 A
Low 0.1 0.25 0.6 A
CS03 VCTH Cap Threshold — 0.8 — mV
CS04 VCTL Cap Threshold — 0.4 — mV
CS05 VCHYST CAP HYSTERESIS
(VCTH - VCTL)
High 350 525 725 mV
Medium 250 375 500 mV
Low 175 300 425 mV
* These parameters are characterized but not tested.
† Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
ISRC
VCTH
VCTL
ISNK
EnabledEnabled
2010 Microchip Technology Inc. Preliminary DS41413A-page 365
PIC12F/LF1822/16F/LF1823
30.0 DC AND AC
CHARACTERISTICS GRAPHS
AND CHARTS
Graphs and charts are not available at this time.
PIC12F/LF1822/16F/LF1823
DS41413A-page 366 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 367
PIC12F/LF1822/16F/LF1823
31.0 DEVELOPMENT SUPPORT
The PIC® microcontrollers are supported with a full
range of hardware and software development tools:
• Integrated Development Environment
- MPLAB® IDE Software
• Assemblers/Compilers/Linkers
- MPASMTM Assembler
- MPLAB C18 and MPLAB C30 C Compilers
-MPLINK
TM Object Linker/
MPLIBTM Object Librarian
- MPLAB ASM30 Assembler/Linker/Library
• Simulators
- MPLAB SIM Software Simulator
•Emulators
- MPLAB ICE 2000 In-Circuit Emulator
- MPLAB REAL ICE™ In-Circuit Emulator
• In-Circuit Debugger
- MPLAB ICD 2
• Device Programmers
- PICSTART® Plus Development Programmer
- MPLAB PM3 Device Programmer
- PICkit™ 2 Development Programmer
• Low-Cost Demonstration and Development
Boards and Evaluation Kits
31.1 MPLAB Integrated Development
Environment Software
The MPLAB IDE software brings an ease of software
development previously unseen in the 8/16-bit micro-
controller market. The MPLAB IDE is a Windows®
operating system-based application that contains:
• A single graphical interface to all debugging tools
- Simulator
- Programmer (sold separately)
- Emulator (sold separately)
- In-Circuit Debugger (sold separately)
• A full-featured editor with color-coded context
• A multiple project manager
• Customizable data windows with direct edit of
contents
• High-level source code debugging
• Visual device initializer for easy register
initialization
• Mouse over variable inspection
• Drag and drop variables from source to watch
windows
• Extensive on-line help
• Integration of select third party tools, such as
HI-TECH Software C Compilers and IAR
C Compilers
The MPLAB IDE allows you to:
• Edit your source files (either assembly or C)
• One touch assemble (or compile) and download
to PIC MCU emulator and simulator tools
(automatically updates all project information)
• Debug using:
- Source files (assembly or C)
- Mixed assembly and C
- Machine code
MPLAB IDE supports multiple debugging tools in a
single development paradigm, from the cost-effective
simulators, through low-cost in-circuit debuggers, to
full-featured emulators. This eliminates the learning
curve when upgrading to tools with increased flexibility
and power.
PIC12F/LF1822/16F/LF1823
DS41413A-page 368 Preliminary 2010 Microchip Technology Inc.
31.2 MPASM Assembler
The MPASM Assembler is a full-featured, universal
macro assembler for all PIC MCUs.
The MPASM Assembler generates relocatable object
files for the MPLINK Object Linker, Intel® standard HEX
files, MAP files to detail memory usage and symbol
reference, absolute LST files that contain source lines
and generated machine code and COFF files for
debugging.
The MPASM Assembler features include:
• Integration into MPLAB IDE projects
• User-defined macros to streamline
assembly code
• Conditional assembly for multi-purpose
source files
• Directives that allow complete control over the
assembly process
31.3 MPLAB C18 and MPLAB C30
C Compilers
The MPLAB C18 and MPLAB C30 Code Development
Systems are complete ANSI C compilers for
Microchip’s PIC18 and PIC24 families of microcon-
trollers and the dsPIC30 and dsPIC33 family of digital
signal controllers. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use not found with other compilers.
For easy source level debugging, the compilers provide
symbol information that is optimized to the MPLAB IDE
debugger.
31.4 MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK Object Linker combines relocatable
objects created by the MPASM Assembler and the
MPLAB C18 C Compiler. It can link relocatable objects
from precompiled libraries, using directives from a
linker script.
The MPLIB Object Librarian manages the creation and
modification of library files of precompiled code. When
a routine from a library is called from a source file, only
the modules that contain that routine will be linked in
with the application. This allows large libraries to be
used efficiently in many different applications.
The object linker/library features include:
• Efficient linking of single libraries instead of many
smaller files
• Enhanced code maintainability by grouping
related modules together
• Flexible creation of libraries with easy module
listing, replacement, deletion and extraction
31.5 MPLAB ASM30 Assembler, Linker
and Librarian
MPLAB ASM30 Assembler produces relocatable
machine code from symbolic assembly language for
dsPIC30F devices. MPLAB C30 C Compiler uses the
assembler to produce its object file. The assembler
generates relocatable object files that can then be
archived or linked with other relocatable object files and
archives to create an executable file. Notable features
of the assembler include:
• Support for the entire dsPIC30F instruction set
• Support for fixed-point and floating-point data
• Command line interface
• Rich directive set
• Flexible macro language
• MPLAB IDE compatibility
31.6 MPLAB SIM Software Simulator
The MPLAB SIM Software Simulator allows code
development in a PC-hosted environment by simulat-
ing the PIC MCUs and dsPIC® DSCs on an instruction
level. On any given instruction, the data areas can be
examined or modified and stimuli can be applied from
a comprehensive stimulus controller. Registers can be
logged to files for further run-time analysis. The trace
buffer and logic analyzer display extend the power of
the simulator to record and track program execution,
actions on I/O, most peripherals and internal registers.
The MPLAB SIM Software Simulator fully supports
symbolic debugging using the MPLAB C18 and
MPLAB C30 C Compilers, and the MPASM and
MPLAB ASM30 Assemblers. The software simulator
offers the flexibility to develop and debug code outside
of the hardware laboratory environment, making it an
excellent, economical software development tool.
2010 Microchip Technology Inc. Preliminary DS41413A-page 369
PIC12F/LF1822/16F/LF1823
31.7 MPLAB ICE 2000
High-Performance
In-Circuit Emulator
The MPLAB ICE 2000 In-Circuit Emulator is intended
to provide the product development engineer with a
complete microcontroller design tool set for PIC
microcontrollers. Software control of the MPLAB ICE
2000 In-Circuit Emulator is advanced by the MPLAB
Integrated Development Environment, which allows
editing, building, downloading and source debugging
from a single environment.
The MPLAB ICE 2000 is a full-featured emulator
system with enhanced trace, trigger and data monitor-
ing features. Interchangeable processor modules allow
the system to be easily reconfigured for emulation of
different processors. The architecture of the MPLAB
ICE 2000 In-Circuit Emulator allows expansion to
support new PIC microcontrollers.
The MPLAB ICE 2000 In-Circuit Emulator system has
been designed as a real-time emulation system with
advanced features that are typically found on more
expensive development tools. The PC platform and
Microsoft® Windows® 32-bit operating system were
chosen to best make these features available in a
simple, unified application.
31.8 MPLAB REAL ICE In-Circuit
Emulator System
MPLAB REAL ICE In-Circuit Emulator System is
Microchip’s next generation high-speed emulator for
Microchip Flash DSC and MCU devices. It debugs and
programs PIC® Flash MCUs and dsPIC® Flash DSCs
with the easy-to-use, powerful graphical user interface of
the MPLAB Integrated Development Environment (IDE),
included with each kit.
The MPLAB REAL ICE probe is connected to the design
engineer’s PC using a high-speed USB 2.0 interface and
is connected to the target with either a connector
compatible with the popular MPLAB ICD 2 system
(RJ11) or with the new high-speed, noise tolerant, Low-
Voltage Differential Signal (LVDS) interconnection
(CAT5).
MPLAB REAL ICE is field upgradeable through future
firmware downloads in MPLAB IDE. In upcoming
releases of MPLAB IDE, new devices will be supported,
and new features will be added, such as software break-
points and assembly code trace. MPLAB REAL ICE
offers significant advantages over competitive emulators
including low-cost, full-speed emulation, real-time
variable watches, trace analysis, complex breakpoints, a
ruggedized probe interface and long (up to three meters)
interconnection cables.
31.9 MPLAB ICD 2 In-Circuit Debugger
Microchip’s In-Circuit Debugger, MPLAB ICD 2, is a
powerful, low-cost, run-time development tool,
connecting to the host PC via an RS-232 or high-speed
USB interface. This tool is based on the Flash PIC
MCUs and can be used to develop for these and other
PIC MCUs and dsPIC DSCs. The MPLAB ICD 2 utilizes
the in-circuit debugging capability built into the Flash
devices. This feature, along with Microchip’s In-Circuit
Serial ProgrammingTM (ICSPTM) protocol, offers cost-
effective, in-circuit Flash debugging from the graphical
user interface of the MPLAB Integrated Development
Environment. This enables a designer to develop and
debug source code by setting breakpoints, single step-
ping and watching variables, and CPU status and
peripheral registers. Running at full speed enables
testing hardware and applications in real time. MPLAB
ICD 2 also serves as a development programmer for
selected PIC devices.
31.10 MPLAB PM3 Device Programmer
The MPLAB PM3 Device Programmer is a universal,
CE compliant device programmer with programmable
voltage verification at VDDMIN and VDDMAX for
maximum reliability. It features a large LCD display
(128 x 64) for menus and error messages and a modu-
lar, detachable socket assembly to support various
package types. The ICSP™ cable assembly is included
as a standard item. In Stand-Alone mode, the MPLAB
PM3 Device Programmer can read, verify and program
PIC devices without a PC connection. It can also set
code protection in this mode. The MPLAB PM3
connects to the host PC via an RS-232 or USB cable.
The MPLAB PM3 has high-speed communications and
optimized algorithms for quick programming of large
memory devices and incorporates an SD/MMC card for
file storage and secure data applications.
PIC12F/LF1822/16F/LF1823
DS41413A-page 370 Preliminary 2010 Microchip Technology Inc.
31.11 PICSTART Plus Development
Programmer
The PICSTART Plus Development Programmer is an
easy-to-use, low-cost, prototype programmer. It
connects to the PC via a COM (RS-232) port. MPLAB
Integrated Development Environment software makes
using the programmer simple and efficient. The
PICSTART Plus Development Programmer supports
most PIC devices in DIP packages up to 40 pins.
Larger pin count devices, such as the PIC16C92X and
PIC17C76X, may be supported with an adapter socket.
The PICSTART Plus Development Programmer is CE
compliant.
31.12 PICkit 2 Development Programmer
The PICkit™ 2 Development Programmer is a low-cost
programmer and selected Flash device debugger with
an easy-to-use interface for programming many of
Microchip’s baseline, mid-range and PIC18F families of
Flash memory microcontrollers. The PICkit 2 Starter Kit
includes a prototyping development board, twelve
sequential lessons, software and HI-TECH’s PICC™
Lite C compiler, and is designed to help get up to speed
quickly using PIC® microcontrollers. The kit provides
everything needed to program, evaluate and develop
applications using Microchip’s powerful, mid-range
Flash memory family of microcontrollers.
31.13 Demonstration, Development and
Evaluation Boards
A wide variety of demonstration, development and
evaluation boards for various PIC MCUs and dsPIC
DSCs allows quick application development on fully func-
tional systems. Most boards include prototyping areas for
adding custom circuitry and provide application firmware
and source code for examination and modification.
The boards support a variety of features, including LEDs,
temperature sensors, switches, speakers, RS-232
interfaces, LCD displays, potentiometers and additional
EEPROM memory.
The demonstration and development boards can be
used in teaching environments, for prototyping custom
circuits and for learning about various microcontroller
applications.
In addition to the PICDEM™ and dsPICDEM™ demon-
stration/development board series of circuits, Microchip
has a line of evaluation kits and demonstration software
for analog filter design, KEELOQ® security ICs, CAN,
IrDA®, PowerSmart battery management, SEEVAL®
evaluation system, Sigma-Delta ADC, flow rate
sensing, plus many more.
Check the Microchip web page (www.microchip.com)
for the complete list of demonstration, development
and evaluation kits.
2010 Microchip Technology Inc. Preliminary DS41413A-page 371
PIC12F/LF1822/16F/LF1823
32.0 PACKAGING INFORMATION
32.1 Package Marking Information
*Standard PICmicro® device marking consists of Microchip part number, year code, week code and
traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check
with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP
price.
Legend: XX...X Customer-specific information
Y Year code (last digit of calendar year)
YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
*This package is Pb-free. The Pb-free JEDEC designator ( )
can be found on the outer packaging for this package.
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
3
e
3
e
XXXXXNNN
8-Lead PDIP
XXXXXXXX
YYWW
017
Example
12F1822/P
0910
8-Lead SOIC (.150”)
XXXXXXXX
XXXXYYWW
NNN
Example
PIC12F1822
/SN0910
017
XXXX
8-Lead DFN (3x3x0.9 mm)
YYWW
NNN
BEQX
Example
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017
PIC12F/LF1822/16F/LF1823
DS41413A-page 372 Preliminary 2010 Microchip Technology Inc.
32.2 Package Marking Information
*Standard PICmicro® device marking consists of Microchip part number, year code, week code and
traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check
with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP
price.
Legend: XX...X Customer-specific information
Y Year code (last digit of calendar year)
YY Year code (last 2 digits of calendar year)
WW Week code (week of January 1 is week ‘01’)
NNN Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
*This package is Pb-free. The Pb-free JEDEC designator ( )
can be found on the outer packaging for this package.
Note: In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
3
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Example
PIC16F1823-I/P
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Example
PIC16F1823
-I/SL
0910017
14-Lead TSSOP
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Example
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16-Lead QFN (4x4x0.9 mm)
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Example
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16F1823
2010 Microchip Technology Inc. Preliminary DS41413A-page 373
PIC12F/LF1822/16F/LF1823
32.3 Package Details
The following sections give the technical details of the packages.
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2010 Microchip Technology Inc. Preliminary DS41413A-page 377
PIC12F/LF1822/16F/LF1823
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DS41413A-page 382 Preliminary 2010 Microchip Technology Inc.
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
2010 Microchip Technology Inc. Preliminary DS41413A-page 383
PIC12F/LF1822/16F/LF1823
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2010 Microchip Technology Inc. Preliminary DS41413A-page 385
PIC12F/LF1822/16F/LF1823
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DS41413A-page 386 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 387
PIC12F/LF1822/16F/LF1823
APPENDIX A: DATA SHEET
REVISION HISTORY
Revision A
Original release (03/2010)
APPENDIX B: MIGRATING FROM
OTHER PIC®
DEVICES
This section provides comparisons when migrating
from other similar PIC® devices to the
PIC12F/LF1822/16F/LF1823 family of devices.
B.1 PIC16F648A to PIC16F/LF1823
TABLE B-1: FEATURE COMPARISON
Feature PIC16F648A PIC16F/LF1823
Max. Operating
Speed
20 MHz 32 MHz
Max. Program
Memory (Words)
4K 4K
Max. SRAM (Bytes) 256 384
Max. EEPROM
(Bytes)
256 256
A/D Resolution 10-bit 10-bit
Timers (8/16-bit) 2/1 4/1
Brown-out Reset Y Y
Internal Pull-ups RB<7:0> RA<5:0>, RA2
Interrupt-on-change RB<7:4> RA<5:0>, Edge
Selectable
Comparator 2 2
AUSART/EUSART 1/0 0/2
Extended WDT N Y
Software Control
Option of WDT/BOR
NY
INTOSC
Frequencies
48 kHz or
4 MHz
31 kHz -
32 MHz
Clock Switching Y Y
Capacitive Sensing N Y
CCP/ECCP 2/0 2/2
Enhanced PIC16
CPU
NY
MSSPx/SSPx 0 2/0
Reference Clock N Y
Data Signal
Modulator
NY
SR Latch N Y
Voltage Reference N Y
DAC Y Y
PIC12F/LF1822/16F/LF1823
DS41413A-page 388 Preliminary 2010 Microchip Technology Inc.
NOTES:
2010 Microchip Technology Inc. Preliminary DS41413A-page 389
PIC12F/LF1822/16F/LF1823
INDEX
A
A/D
Specifications............................................................ 355
Absolute Maximum Ratings .............................................. 333
AC Characteristics
Industrial and Extended ............................................ 348
Load Conditions ........................................................ 347
ACKSTAT ......................................................................... 261
ACKSTAT Status Flag ...................................................... 261
ADC .................................................................................. 133
Acquisition Requirements ......................................... 143
Associated registers.................................................. 145
Block Diagram........................................................... 133
Calculating Acquisition Time..................................... 143
Channel Selection..................................................... 134
Configuration............................................................. 134
Configuring Interrupt ................................................. 138
Conversion Clock...................................................... 134
Conversion Procedure .............................................. 138
Internal Sampling Switch (RSS) Impedance.............. 143
Interrupts................................................................... 136
Operation .................................................................. 137
Operation During Sleep ............................................ 137
Port Configuration..................................................... 134
Reference Voltage (VREF)......................................... 134
Source Impedance.................................................... 143
Special Event Trigger................................................ 137
Starting an A/D Conversion ......................................136
ADCON0 Register....................................................... 32, 139
ADCON1 Register....................................................... 32, 140
ADDFSR ........................................................................... 323
ADDWFC .......................................................................... 323
ADRESH Register............................................................... 32
ADRESH Register (ADFM = 0) ......................................... 141
ADRESH Register (ADFM = 1) ......................................... 142
ADRESL Register (ADFM = 0).......................................... 141
ADRESL Register (ADFM = 1).......................................... 142
Alternate Pin Function.......................................................117
Analog-to-Digital Converter. See ADC
ANSELA Register ............................................................. 122
ANSELC Register ............................................................. 126
APFCON0 Register........................................................... 118
Assembler
MPASM Assembler................................................... 368
B
BAUDCON Register.......................................................... 290
BF ............................................................................. 261, 263
BF Status Flag .......................................................... 261, 263
Block Diagram
Capacitive Sensing ........................................... 307, 308
Block Diagrams
(CCP) Capture Mode Operation ............................... 200
ADC .......................................................................... 133
ADC Transfer Function ............................................. 144
Analog Input Model ........................................... 144, 164
CCP PWM................................................................. 204
Clock Source............................................................... 55
Comparator ............................................................... 160
Compare ................................................................... 202
Crystal Operation .................................................. 57, 58
Digital-to-Analog Converter (DAC)............................ 149
EUSART Receive ..................................................... 280
EUSART Transmit .................................................... 279
External RC Mode ...................................................... 58
Fail-Safe Clock Monitor (FSCM)................................. 66
Generic I/O Port........................................................ 117
Interrupt Logic............................................................. 83
On-Chip Reset Circuit................................................. 75
Peripheral Interrupt Logic ........................................... 84
PIC16F/LF1826/27 ..................................................... 12
PIC16F193X/LF193X ................................................. 20
PWM (Enhanced) ..................................................... 208
Resonator Operation .................................................. 57
Timer0 ...................................................................... 169
Timer1 ...................................................................... 172
Timer1 Gate.............................................. 177, 178, 179
Timer2 ...................................................................... 184
Voltage Reference.................................................... 131
Voltage Reference Output Buffer Example .............. 150
BORCON Register.............................................................. 77
BRA .................................................................................. 324
Break Character (12-bit) Transmit and Receive ............... 299
Brown-out Reset (BOR)...................................................... 77
Specifications ........................................................... 353
Timing and Characteristics ....................................... 352
C
C Compilers
MPLAB C18.............................................................. 368
MPLAB C30.............................................................. 368
CALL................................................................................. 325
CALLW ............................................................................. 325
Capacitive Sensing ........................................................... 307
Associated registers w/ Capacitive Sensing............. 314
Specifications ........................................................... 364
Capture Module. See Enhanced Capture/Compare/
PWM (ECCP)
Capture/Compare/PWM ................................................... 199
Capture/Compare/PWM (CCP)
Associated Registers w/ Capture ............................. 201
Associated Registers w/ Compare ........................... 203
Associated Registers w/ PWM ......................... 207, 220
Capture Mode........................................................... 200
CCPx Pin Configuration............................................ 200
Compare Mode......................................................... 202
CCPx Pin Configuration.................................... 202
Software Interrupt Mode........................... 200, 202
Special Event Trigger ....................................... 202
Timer1 Mode Resource ............................ 200, 202
Prescaler .................................................................. 200
PWM Mode
Duty Cycle ........................................................ 205
Effects of Reset ................................................ 207
Example PWM Frequencies and
Resolutions, 20 MHZ................................ 206
Example PWM Frequencies and
Resolutions, 32 MHZ................................ 206
Example PWM Frequencies and
Resolutions, 8 MHz .................................. 206
Operation in Sleep Mode.................................. 207
Resolution ........................................................ 206
System Clock Frequency Changes .................. 207
PWM Operation ........................................................ 204
PWM Overview......................................................... 204
PWM Period ............................................................. 205
PWM Setup .............................................................. 205
PIC12F/LF1822/16F/LF1823
DS41413A-page 390 Preliminary 2010 Microchip Technology Inc.
CCP1AS Register ............................................................. 222
CCP1CON Register ............................................................36
CCPR1H Register ...............................................................36
CCPR1L Register................................................................ 36
CCPxCON (ECCPx) Register ........................................... 221
CLKRCON Register ............................................................ 72
Clock Accuracy with Asynchronous Operation ................. 288
Clock Sources
External Modes ...........................................................56
EC ....................................................................... 56
HS ....................................................................... 56
LP........................................................................56
OST..................................................................... 57
RC....................................................................... 58
XT ....................................................................... 56
Internal Modes ............................................................ 59
HFINTOSC.......................................................... 59
Internal Oscillator Clock Switch Timing...............61
LFINTOSC .......................................................... 60
MFINTOSC ......................................................... 59
Clock Switching................................................................... 63
CMOUT Register............................................................... 166
CMxCON0 Register ..........................................................165
CMxCON1 Register ..........................................................166
Code Examples
A/D Conversion......................................................... 138
Changing Between Capture Prescalers .................... 200
Initializing PORTA.....................................................119
Initializing PORTC.....................................................124
Write Verify ............................................................... 113
Writing to Flash Program Memory ............................111
Comparator
Associated Registers ................................................ 167
Operation .................................................................. 159
Comparator Module ..........................................................159
Cx Output State Versus Input Conditions ................. 162
Comparator Specifications................................................ 357
Comparators
C2OUT as T1 Gate ...................................................174
Compare Module. See Enhanced Capture/
Compare/PWM (ECCP)
CONFIG1 Register..............................................................50
CONFIG2 Register..............................................................52
CPSCON0 Register .......................................................... 313
CPSCON1 Register .......................................................... 314
Customer Change Notification Service ............................. 395
Customer Notification Service...........................................395
Customer Support ............................................................. 395
D
DACCON0 (Digital-to-Analog Converter Control 0)
Register....................................................................151
DACCON1 (Digital-to-Analog Converter Control 1)
Register....................................................................151
Data EEPROM Memory .................................................... 103
Associated Registers ................................................ 116
Code Protection ........................................................ 104
Reading..................................................................... 104
Writing....................................................................... 104
Data Memory....................................................................... 23
DC and AC Characteristics ............................................... 365
DC Characteristics
Extended and Industrial ............................................ 344
Industrial and Extended ............................................ 336
Development Support ....................................................... 367
Device Configuration...........................................................49
Code Protection.......................................................... 53
Configuration Word..................................................... 49
User ID ................................................................. 53, 54
Device Overview........................................................... 11, 99
Digital-to-Analog Converter (DAC) ................................... 147
Associated Registers ................................................ 152
Effects of a Reset ..................................................... 149
Specifications ........................................................... 357
E
ECCP/CCP. See Enhanced Capture/Compare/PWM
EEADR Registers ............................................................. 103
EEADRH Registers........................................................... 103
EEADRL Register............................................................. 114
EEADRL Registers ........................................................... 103
EECON1 Register..................................................... 103, 115
EECON2 Register..................................................... 103, 116
EEDATH Register............................................................. 114
EEDATL Register ............................................................. 114
EEPROM Data Memory
Avoiding Spurious Write ........................................... 104
Write Verify ............................................................... 113
Effects of Reset
PWM mode............................................................... 207
Electrical Specifications.................................................... 333
Enhanced Capture/Compare/PWM (ECCP)..................... 200
Enhanced PWM Mode.............................................. 208
Auto-Restart ..................................................... 216
Auto-shutdown.................................................. 215
Direction Change in Full-Bridge Output Mode.. 214
Full-Bridge Application...................................... 212
Full-Bridge Mode .............................................. 212
Half-Bridge Application ..................................... 211
Half-Bridge Application Examples .................... 217
Half-Bridge Mode.............................................. 211
Output Relationships (Active-High and
Active-Low)............................................... 209
Output Relationships Diagram.......................... 210
Programmable Dead Band Delay..................... 217
Shoot-through Current...................................... 217
Start-up Considerations .................................... 219
Specifications ........................................................... 354
Enhanced Mid-range CPU.................................................. 19
Enhanced Universal Synchronous Asynchronous
Receiver Transmitter (EUSART) .............................. 279
Errata .................................................................................. 10
EUSART ........................................................................... 279
Associated Registers
Baud Rate Generator ....................................... 292
Asynchronous Mode ................................................. 281
12-bit Break Transmit and Receive .................. 299
Associated Registers
Receive .................................................... 287
Transmit.................................................... 283
Auto-Wake-up on Break ................................... 297
Baud Rate Generator (BRG) ............................ 291
Clock Accuracy................................................. 288
Receiver ........................................................... 284
Setting up 9-bit Mode with Address Detect ...... 286
Transmitter ....................................................... 281
Baud Rate Generator (BRG)
Auto Baud Rate Detect..................................... 296
Baud Rate Error, Calculating............................ 291
Baud Rates, Asynchronous Modes .................. 293
Formulas........................................................... 292
High Baud Rate Select (BRGH Bit) .................. 291
2010 Microchip Technology Inc. Preliminary DS41413A-page 391
PIC12F/LF1822/16F/LF1823
Synchronous Master Mode ............................... 300, 304
Associated Registers
Receive..................................................... 303
Transmit.................................................... 301
Reception.......................................................... 302
Transmission .................................................... 300
Synchronous Slave Mode
Associated Registers
Receive..................................................... 305
Transmit.................................................... 304
Reception.......................................................... 305
Transmission .................................................... 304
Extended Instruction Set
ADDFSR ................................................................... 323
F
Fail-Safe Clock Monitor....................................................... 66
Fail-Safe Condition Clearing....................................... 66
Fail-Safe Detection ..................................................... 66
Fail-Safe Operation..................................................... 66
Reset or Wake-up from Sleep..................................... 66
Firmware Instructions........................................................ 319
Fixed Voltage Reference (FVR)........................................ 131
Associated Registers ................................................ 132
Flash Program Memory .................................................... 103
Erasing...................................................................... 108
Modifying................................................................... 112
Writing....................................................................... 108
FSR Register .......... 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
FVRCON (Fixed Voltage Reference Control) Register..... 132
I
I2C Mode (MSSPx)
Acknowledge Sequence Timing................................ 265
Bus Collision
During a Repeated Start Condition................... 270
During a Stop Condition.................................... 271
Effects of a Reset...................................................... 266
I2C Clock Rate w/BRG.............................................. 273
Master Mode
Operation .......................................................... 257
Reception.......................................................... 263
Start Condition Timing .............................. 259, 260
Transmission .................................................... 261
Multi-Master Communication, Bus Collision
and Arbitration .................................................. 266
Multi-Master Mode .................................................... 266
Read/Write Bit Information (R/W Bit) ........................ 242
Slave Mode
Transmission .................................................... 247
Sleep Operation ........................................................ 266
Stop Condition Timing............................................... 265
INDF Register ......... 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
Indirect Addressing ............................................................. 45
Instruction Format............................................................. 320
Instruction Set ................................................................... 319
ADDLW ..................................................................... 323
ADDWF..................................................................... 323
ADDWFC .................................................................. 323
ANDLW ..................................................................... 323
ANDWF..................................................................... 323
BRA........................................................................... 324
CALL ......................................................................... 325
CALLW...................................................................... 325
LSLF ......................................................................... 327
LSRF......................................................................... 327
MOVF ....................................................................... 327
MOVIW ..................................................................... 328
MOVLB ..................................................................... 328
MOVWI..................................................................... 329
OPTION.................................................................... 329
RESET...................................................................... 329
SUBWFB .................................................................. 331
TRIS ......................................................................... 332
BCF .......................................................................... 324
BSF........................................................................... 324
BTFSC...................................................................... 324
BTFSS ...................................................................... 324
CALL......................................................................... 325
CLRF ........................................................................ 325
CLRW ....................................................................... 325
CLRWDT .................................................................. 325
COMF ....................................................................... 325
DECF........................................................................ 325
DECFSZ ................................................................... 326
GOTO ....................................................................... 326
INCF ......................................................................... 326
INCFSZ..................................................................... 326
IORLW...................................................................... 326
IORWF...................................................................... 326
MOVLW .................................................................... 328
MOVWF.................................................................... 328
NOP.......................................................................... 329
RETFIE..................................................................... 330
RETLW ..................................................................... 330
RETURN................................................................... 330
RLF........................................................................... 330
RRF .......................................................................... 331
SLEEP ...................................................................... 331
SUBLW..................................................................... 331
SUBWF..................................................................... 331
SWAPF..................................................................... 332
XORLW .................................................................... 332
XORWF .................................................................... 332
INTCON Register................................................................ 89
Internal Oscillator Block
INTOSC
Specifications ................................................... 349
Internal Sampling Switch (RSS) Impedance ..................... 143
Internet Address ............................................................... 395
Interrupt-On-Change......................................................... 127
Associated Registers................................................ 129
Interrupts ............................................................................ 83
ADC .......................................................................... 138
Associated registers w/ Interrupts .............................. 94
Configuration Word w/ Clock Sources........................ 70
Configuration Word w/ Reference Clock Sources ...... 73
TMR1........................................................................ 176
INTOSC Specifications ..................................................... 349
IOCAF Register ................................................................ 128
IOCAN Register................................................................ 128
IOCAP Register ................................................................ 128
L
LATA Register .......................................................... 122, 125
Load Conditions................................................................ 347
LSLF ................................................................................. 327
LSRF ................................................................................ 327
M
Master Synchronous Serial Port. See MSSPx
MCLR ................................................................................. 78
PIC12F/LF1822/16F/LF1823
DS41413A-page 392 Preliminary 2010 Microchip Technology Inc.
Internal ........................................................................78
MDCARH Register............................................................196
MDCARL Register.............................................................197
MDCON Register .............................................................. 194
MDSRC Register...............................................................195
Memory Organization.......................................................... 21
Data ............................................................................ 23
Program ......................................................................21
Microchip Internet Web Site..............................................395
Migrating from other PIC Microcontroller Devices............. 387
MOVIW.............................................................................. 328
MOVLB.............................................................................. 328
MOVWI.............................................................................. 329
MPLAB ASM30 Assembler, Linker, Librarian ................... 368
MPLAB ICD 2 In-Circuit Debugger.................................... 369
MPLAB ICE 2000 High-Performance Universal
In-Circuit Emulator ....................................................369
MPLAB Integrated Development Environment Software .. 367
MPLAB PM3 Device Programmer.....................................369
MPLAB REAL ICE In-Circuit Emulator System.................369
MPLINK Object Linker/MPLIB Object Librarian ................368
MSSPx .............................................................................. 225
I2C Mode Operation .................................................. 238
SPI Mode ..................................................................228
SSPxBUF Register ...................................................232
SSPxSR Register...................................................... 232
O
OPCODE Field Descriptions ............................................. 319
OPTION ............................................................................ 329
OPTION Register..............................................................171
OSCCON Register.............................................................. 68
Oscillator
Associated Registers ..................................................70
Oscillator Module ................................................................55
EC ............................................................................... 55
HS ............................................................................... 55
INTOSC ......................................................................55
LP................................................................................ 55
RC............................................................................... 55
XT ............................................................................... 55
Oscillator Parameters........................................................ 349
Oscillator Specifications.................................................... 348
Oscillator Start-up Timer (OST)
Specifications............................................................ 353
Oscillator Switching
Fail-Safe Clock Monitor...............................................66
Two-Speed Clock Start-up.......................................... 64
OSCSTAT Register.............................................................69
OSCTUNE Register ............................................................ 70
P
P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/PWM
(ECCP)......................................................................208
Packaging ......................................................................... 371
Marking ............................................................. 371, 372
PDIP Details..............................................................373
PCL and PCLATH ............................................................... 20
PCL Register...........31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
PCLATH Register.... 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
PCON Register ............................................................. 32, 81
PICSTART Plus Development Programmer ..................... 370
PIE1 Register................................................................32, 90
PIE2 Register......................................................................91
Pinout Descriptions
PIC16F/LF1826/27................................................ 13, 15
PIR1 Register ............................................................... 31, 92
PIR2 Register ......................................................... 31, 32, 93
PORTA ............................................................................. 119
ANSELA Register ..................................................... 119
Associated Registers ................................................ 123
Configuration Word w/ PORTA................................. 123
LATA Register ............................................................ 33
PORTA Register......................................................... 31
Specifications ........................................................... 351
PORTA Register............................................................... 121
PORTC ............................................................................. 124
ANSELC Register ..................................................... 124
Associated Registers ................................................ 126
LATC Register ............................................................ 33
Pin Descriptions and Diagrams ................................ 124
PORTC Register......................................................... 31
PORTC Register............................................................... 125
Power-Down Mode (Sleep)................................................. 95
Associated Registers.......................................... 97, 197
Power-on Reset.................................................................. 76
Power-up Time-out Sequence ............................................ 78
Power-up Timer (PWRT) .................................................... 76
Specifications ........................................................... 353
PR2 Register ...................................................................... 31
Precision Internal Oscillator Parameters .......................... 349
Program Memory ................................................................ 21
Map and Stack (PIC16F/LF1826) ............................... 22
Map and Stack (PIC16F/LF1826/27) .................... 21, 22
Programming, Device Instructions.................................... 319
PSTRxCON Register........................................................ 224
PWM (ECCP Module)
PWM Steering........................................................... 218
Steering Synchronization.......................................... 219
PWM Mode. See Enhanced Capture/Compare/PWM ...... 208
PWM Steering................................................................... 218
PWM1CON Register......................................................... 223
R
RCREG............................................................................. 286
RCREG Register ................................................................ 34
RCSTA Register ......................................................... 34, 289
Reader Response............................................................. 396
Read-Modify-Write Operations ......................................... 319
Reference Clock ................................................................. 71
Associated Registers .................................................. 73
Registers
ADCON0 (ADC Control 0) ........................................ 139
ADCON1 (ADC Control 1) ........................................ 140
ADRESH (ADC Result High) with ADFM = 0) .......... 141
ADRESH (ADC Result High) with ADFM = 1) .......... 142
ADRESL (ADC Result Low) with ADFM = 0)............ 141
ADRESL (ADC Result Low) with ADFM = 1)............ 142
ANSELA (PORTA Analog Select)............................. 122
ANSELC (PORTC Analog Select) ............................ 126
APFCON0 (Alternate Pin Function Control 0) .......... 118
BAUDCON (Baud Rate Control)............................... 290
BORCON Brown-out Reset Control) .......................... 77
CCP1AS (CCP1 Auto-Shutdown Control) ................ 222
CCPxCON (ECCPx Control)..................................... 221
CLKRCON (Reference Clock Control)........................ 72
CMOUT (Comparator Output) .................................. 166
CMxCON0 (Cx Control)............................................ 165
CMxCON1 (Cx Control 1)......................................... 166
Configuration Word 1.................................................. 50
Configuration Word 2.................................................. 52
2010 Microchip Technology Inc. Preliminary DS41413A-page 393
PIC12F/LF1822/16F/LF1823
CPSCON0 (Capacitive Sensing Control
Register 0) ........................................................ 313
CPSCON1 (Capacitive Sensing Control Register 1) 314
DACCON0 ................................................................ 151
DACCON1 ................................................................ 151
EEADRL (EEPROM Address) .................................. 114
EECON1 (EEPROM Control 1)................................. 115
EECON2 (EEPROM Control 2)................................. 116
EEDATH (EEPROM Data)........................................ 114
EEDATL (EEPROM Data) ........................................ 114
FVRCON................................................................... 132
INTCON (Interrupt Control)......................................... 89
IOCAF (Interrupt-on-Change PORTA Flag).............. 128
IOCAN (Interrupt-on-Change PORTA
Negative Edge) ................................................. 128
IOCAP (Interrupt-on-Change PORTA
Positive Edge)................................................... 128
LATA (Data Latch PORTA)....................................... 122
LATC (Data Latch PORTC) ...................................... 125
MDCARH (Modulation High Carrier
Control Register)............................................... 196
MDCARL (Modulation Low Carrier
Control Register)............................................... 197
MDCON (Modulation Control Register) .................... 194
MDSRC (Modulation Source Control Register) ........ 195
OPTION_REG (OPTION) ......................................... 171
OSCCON (Oscillator Control) ..................................... 68
OSCSTAT (Oscillator Status) ..................................... 69
OSCTUNE (Oscillator Tuning).................................... 70
PCON (Power Control Register) ................................. 81
PCON (Power Control) ............................................... 81
PIE1 (Peripheral Interrupt Enable 1)........................... 90
PIE2 (Peripheral Interrupt Enable 2)........................... 91
PIR1 (Peripheral Interrupt Register 1) ........................ 92
PIR2 (Peripheral Interrupt Request 2) ........................ 93
PORTA...................................................................... 121
PORTC ..................................................................... 125
PSTRxCON (PWM Steering Control) ....................... 224
PWM1CON (Enhanced PWM Control) ..................... 223
RCREG ..................................................................... 296
RCSTA (Receive Status and Control)....................... 289
SPBRGH................................................................... 291
SPBRGL ................................................................... 291
Special Function, Summary ........................................ 31
SRCON0 (SR Latch Control 0) ................................. 155
SRCON1 (SR Latch Control 1) ................................. 156
SSPxADD (MSSPx Address and Baud Rate,
I2C Mode) ......................................................... 278
SSPxCON1 (MSSPx Control 1) ................................ 275
SSPxCON2 (SSPx Control 2)................................... 276
SSPxCON3 (SSPx Control 3)................................... 277
SSPxMSK (SSPx Mask) ........................................... 278
SSPxSTAT (SSPx Status) ........................................ 274
STATUS...................................................................... 24
T1CON (Timer1 Control)........................................... 180
T1GCON (Timer1 Gate Control)............................... 181
T2CON...................................................................... 186
TRISA (Tri-State PORTA)......................................... 121
TRISC (Tri-State PORTC) ........................................ 125
TXSTA (Transmit Status and Control) ...................... 288
WDTCON (Watchdog Timer Control) ....................... 101
WPUB (Weak Pull-up PORTB)................................. 123
WPUC (Weak Pull-up PORTC)................................. 126
RESET .............................................................................. 329
Reset................................................................................... 75
Reset Instruction................................................................. 78
Resets ................................................................................ 75
Associated Registers.................................................. 82
Revision History................................................................ 387
S
Shoot-through Current ...................................................... 217
Software Simulator (MPLAB SIM) .................................... 368
SPBRG Register................................................................. 34
SPBRGH Register ............................................................ 291
SPBRGL Register............................................................. 291
Special Event Trigger ....................................................... 137
Special Function Registers (SFRs)..................................... 31
SPI Mode (MSSPx)
Associated Registers................................................ 236
SPI Clock.................................................................. 232
SR Latch........................................................................... 153
Associated registers w/ SR Latch............................. 157
SRCON0 Register ............................................................ 155
SRCON1 Register ............................................................ 156
SSP1ADD Register............................................................. 35
SSP1BUF Register ............................................................. 35
SSP1CON Register ............................................................ 35
SSP1CON2 Register .......................................................... 35
SSP1CON3 Register .......................................................... 35
SSP1MSK Register ............................................................ 35
SSP1STAT Register ........................................................... 35
SSPxADD Register........................................................... 278
SSPxCON1 Register ........................................................ 275
SSPxCON2 Register ........................................................ 276
SSPxCON3 Register ........................................................ 277
SSPxMSK Register........................................................... 278
SSPxOV ........................................................................... 263
SSPxOV Status Flag ........................................................ 263
SSPxSTAT Register ......................................................... 274
R/W Bit ..................................................................... 242
Stack................................................................................... 43
Accessing ................................................................... 43
Reset .......................................................................... 45
Stack Overflow/Underflow .................................................. 78
STATUS Register ............................................................... 24
SUBWFB .......................................................................... 331
T
T1CON Register ......................................................... 31, 180
T1GCON Register ............................................................ 181
T2CON (Timer2) Register................................................. 186
T2CON Register ................................................................. 31
Thermal Considerations.................................................... 346
Timer0 .............................................................................. 169
Associated Registers................................................ 171
Operation.................................................................. 169
Specifications ........................................................... 354
Timer1 .............................................................................. 172
Associated registers ................................................. 182
Asynchronous Counter Mode ................................... 174
Reading and Writing......................................... 174
Clock Source Selection ............................................ 173
Interrupt .................................................................... 176
Operation.................................................................. 173
Operation During Sleep ............................................ 176
Oscillator................................................................... 174
Prescaler .................................................................. 174
Specifications ........................................................... 354
Timer1 Gate
Selecting Source .............................................. 174
PIC12F/LF1822/16F/LF1823
DS41413A-page 394 Preliminary 2010 Microchip Technology Inc.
TMR1H Register ....................................................... 172
TMR1L Register........................................................ 172
Timer2 ............................................................................... 184
Associated registers.................................................. 187
Timer2/4/6
Associated registers.................................................. 187
Timers
Timer1
T1CON.............................................................. 180
T1GCON ........................................................... 181
Timer2
T2CON.............................................................. 186
Timing Diagrams
A/D Conversion......................................................... 356
A/D Conversion (Sleep Mode) .................................. 356
Acknowledge Sequence ........................................... 265
Asynchronous Reception .......................................... 286
Asynchronous Transmission ..................................... 282
Asynchronous Transmission (Back to Back) ............ 282
Auto Wake-up Bit (WUE) During Normal Operation . 298
Auto Wake-up Bit (WUE) During Sleep .................... 298
Automatic Baud Rate Calibration.............................. 296
Baud Rate Generator with Clock Arbitration ............. 258
BRG Reset Due to SDA Arbitration During Start
Condition........................................................... 269
Brown-out Reset (BOR) ............................................ 352
Brown-out Reset Situations ........................................77
Bus Collision During a Repeated Start Condition
(Case 1) ............................................................270
Bus Collision During a Repeated Start Condition
(Case 2) ............................................................270
Bus Collision During a Start Condition (SCL = 0) .....269
Bus Collision During a Stop Condition (Case 1) .......271
Bus Collision During a Stop Condition (Case 2) .......271
Bus Collision During Start Condition (SDA only) ...... 268
Bus Collision for Transmit and Acknowledge............ 267
CLKOUT and I/O....................................................... 350
Clock Synchronization .............................................. 255
Clock Timing .............................................................348
Comparator Output ...................................................159
Enhanced Capture/Compare/PWM (ECCP) ............. 354
Fail-Safe Clock Monitor (FSCM) .................................67
First Start Bit Timing .................................................259
Full-Bridge PWM Output ........................................... 213
Half-Bridge PWM Output .................................. 211, 217
I2C Bus Data .............................................................362
I2C Bus Start/Stop Bits.............................................. 361
I2C Master Mode (7 or 10-Bit Transmission) ............ 262
I2C Master Mode (7-Bit Reception)........................... 264
I2C Stop Condition Receive or Transmit Mode ......... 266
INT Pin Interrupt.......................................................... 87
Internal Oscillator Switch Timing.................................62
PWM Auto-shutdown ................................................216
Firmware Restart ..............................................216
PWM Direction Change ............................................ 214
PWM Direction Change at Near 100% Duty Cycle ... 215
PWM Output (Active-High)........................................209
PWM Output (Active-Low) ........................................210
Repeat Start Condition.............................................. 260
Reset Start-up Sequence............................................79
Reset, WDT, OST and Power-up Timer ................... 351
Send Break Character Sequence ............................. 299
SPI Master Mode (CKE = 1, SMP = 1) .....................359
SPI Mode (Master Mode) .......................................... 232
SPI Slave Mode (CKE = 0) .......................................360
SPI Slave Mode (CKE = 1) ....................................... 360
Synchronous Reception (Master Mode, SREN) ....... 303
Synchronous Transmission ...................................... 301
Synchronous Transmission (Through TXEN) ........... 301
Timer0 and Timer1 External Clock ........................... 353
Timer1 Incrementing Edge ....................................... 176
Two Speed Start-up.................................................... 65
USART Synchronous Receive (Master/Slave) ......... 358
USART Synchronous Transmission
(Master/Slave) .................................................. 358
Wake-up from Interrupt............................................... 96
Timing Diagrams and Specifications
PLL Clock ................................................................. 349
Timing Parameter Symbology .......................................... 347
Timing Requirements
I2C Bus Data............................................................. 363
SPI Mode .................................................................. 361
TMR0 Register.................................................................... 31
TMR1H Register................................................................. 31
TMR1L Register.................................................................. 31
TMR2 Register.................................................................... 31
TRIS.................................................................................. 332
TRISA Register........................................................... 32, 121
TRISC Register........................................................... 32, 125
Two-Speed Clock Start-up Mode........................................ 64
TXREG ............................................................................. 281
TXREG Register................................................................. 34
TXSTA Register.......................................................... 34, 288
BRGH Bit .................................................................. 291
U
USART
Synchronous Master Mode
Requirements, Synchronous Receive .............. 358
Requirements, Synchronous Transmission...... 358
Timing Diagram, Synchronous Receive ........... 358
Timing Diagram, Synchronous Transmission... 358
V
VREF. SEE ADC Reference Voltage
W
Wake-up on Break............................................................ 297
Wake-up Using Interrupts ................................................... 96
Watchdog Timer (WDT)...................................................... 78
Modes ....................................................................... 100
Specifications ........................................................... 353
WCOL ....................................................... 258, 261, 263, 265
WCOL Status Flag.................................... 258, 261, 263, 265
WDTCON Register ........................................................... 101
WPUB Register................................................................. 123
WPUC Register ................................................................ 126
Write Protection .................................................................. 53
WWW Address ................................................................. 395
WWW, On-Line Support ..................................................... 10
2010 Microchip Technology Inc. Preliminary DS41413A-page 395
PIC12F/LF1822/16F/LF1823
THE MICROCHIP WEB SITE
Microchip provides online support via our WWW site at
www.microchip.com. This web site is used as a means
to make files and information easily available to
customers. Accessible by using your favorite Internet
browser, the web site contains the following
information:
•Product Support – Data sheets and errata,
application notes and sample programs, design
resources, user’s guides and hardware support
documents, latest software releases and archived
software
•General Technical Support – Frequently Asked
Questions (FAQ), technical support requests,
online discussion groups, Microchip consultant
program member listing
•Business of Microchip – Product selector and
ordering guides, latest Microchip press releases,
listing of seminars and events, listings of
Microchip sales offices, distributors and factory
representatives
CUSTOMER CHANGE NOTIFICATION
SERVICE
Microchip’s customer notification service helps keep
customers current on Microchip products. Subscribers
will receive e-mail notification whenever there are
changes, updates, revisions or errata related to a
specified product family or development tool of interest.
To register, access the Microchip web site at
www.microchip.com, click on Customer Change
Notification and follow the registration instructions.
CUSTOMER SUPPORT
Users of Microchip products can receive assistance
through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Technical Support
• Development Systems Information Line
Customers should contact their distributor,
representative or field application engineer (FAE) for
support. Local sales offices are also available to help
customers. A listing of sales offices and locations is
included in the back of this document.
Technical support is available through the web site
at: http://support.microchip.com
PIC12F/LF1822/16F/LF1823
DS41413A-page 396 Preliminary 2010 Microchip Technology Inc.
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip prod-
uct. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150.
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DS41413APIC12F/LF1822/16F/LF1823
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
2010 Microchip Technology Inc. Preliminary DS41413A-page 397
PIC12F/LF1822/16F/LF1823
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO. X/XX XXX
PatternPackageTemperature
Range
Device
Device: PIC12F1822(1), PIC16F1823(1), PIC12F1822T(2),
PIC16F1823T(2);
VDD range 1.8V to 5.5V
PIC12LF1822(1), PIC16LF1823(1), PIC12LF1822T(2),
PIC16LF1823T(2);
VDD range 1.8V to 3.6V
Temperature
Range:
I= -40C to +85C (Industrial)
E= -40C to +125C (Extended)
Package: MF = Micro Lead Frame (DFN) 3x3
ML = Micro Lead Frame (QFN) 6x6
P = Plastic DIP
SL = SOIC, 14 lead
SN = SOIC, 8 lead
SS = SSOP
ST = TSSOP
Pattern: QTP, SQTP, Code or Special Requirements
(blank otherwise)
Examples:
a) PIC12F1822 - I/ML 301 = Industrial temp., QFN
package, Extended VDD limits, QTP pattern
#301.
b) PIC16F1823 - I/P = Industrial temp., PDIP
package, Extended VDD limits.
c) PIC16F1823 - E/SS= Extended temp., SSOP
package, normal VDD limits.
Note 1: F = Wide Voltage Range
LF = Standard Voltage Range
2: T = in tape and reel SOIC, SSOP,
TSSOP, and QFN packages only.
DS41413A-page 398 Preliminary 2010 Microchip Technology Inc.
AMERICAS
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://support.microchip.com
Web Address:
www.microchip.com
Atlanta
Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
Chicago
Itasca, IL
Tel: 630-285-0071
Fax: 630-285-0075
Cleveland
Independence, OH
Tel: 216-447-0464
Fax: 216-447-0643
Dallas
Addison, TX
Tel: 972-818-7423
Fax: 972-818-2924
Detroit
Farmington Hills, MI
Tel: 248-538-2250
Fax: 248-538-2260
Kokomo
Kokomo, IN
Tel: 765-864-8360
Fax: 765-864-8387
Los Angeles
Mission Viejo, CA
Tel: 949-462-9523
Fax: 949-462-9608
Santa Clara
Santa Clara, CA
Tel: 408-961-6444
Fax: 408-961-6445
Toronto
Mississauga, Ontario,
Canada
Tel: 905-673-0699
Fax: 905-673-6509
ASIA/PACIFIC
Asia Pacific Office
Suites 3707-14, 37th Floor
Tower 6, The Gateway
Harbour City, Kowloon
Hong Kong
Tel: 852-2401-1200
Fax: 852-2401-3431
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
China - Beijing
Tel: 86-10-8528-2100
Fax: 86-10-8528-2104
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
China - Chongqing
Tel: 86-23-8980-9588
Fax: 86-23-8980-9500
China - Hong Kong SAR
Tel: 852-2401-1200
Fax: 852-2401-3431
China - Nanjing
Tel: 86-25-8473-2460
Fax: 86-25-8473-2470
China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
China - Shenyang
Tel: 86-24-2334-2829
Fax: 86-24-2334-2393
China - Shenzhen
Tel: 86-755-8203-2660
Fax: 86-755-8203-1760
China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
China - Xian
Tel: 86-29-8833-7252
Fax: 86-29-8833-7256
China - Xiamen
Tel: 86-592-2388138
Fax: 86-592-2388130
China - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049
ASIA/PACIFIC
India - Bangalore
Tel: 91-80-3090-4444
Fax: 91-80-3090-4123
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
India - Pune
Tel: 91-20-2566-1512
Fax: 91-20-2566-1513
Japan - Yokohama
Tel: 81-45-471- 6166
Fax: 81-45-471-6122
Korea - Daegu
Tel: 82-53-744-4301
Fax: 82-53-744-4302
Korea - Seoul
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
Malaysia - Kuala Lumpur
Tel: 60-3-6201-9857
Fax: 60-3-6201-9859
Malaysia - Penang
Tel: 60-4-227-8870
Fax: 60-4-227-4068
Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069
Singapore
Tel: 65-6334-8870
Fax: 65-6334-8850
Taiwan - Hsin Chu
Tel: 886-3-6578-300
Fax: 886-3-6578-370
Taiwan - Kaohsiung
Tel: 886-7-536-4818
Fax: 886-7-536-4803
Taiwan - Taipei
Tel: 886-2-2500-6610
Fax: 886-2-2508-0102
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
EUROPE
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
UK - Wokingham
Tel: 44-118-921-5869
Fax: 44-118-921-5820
WORLDWIDE SALES AND SERVICE
01/05/10
