PIC16F819-I/PG - Microchip Technology

 2004 Microchip Technology Inc. DS39598E

PIC16F818/819

Data Sheet

18/20-Pin

Enhanced Flash Microcontrollers

with nanoWatt Technology

DS39598E-page ii  2004 Microchip Technology Inc.

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Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our

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 2004 Microchip Technology Inc. DS39598E-page 1

PIC16F818/819

Low-Power Features:

• Power-Managed modes:

- Primary Run: XT, RC oscillator,

87 µA, 1 MHz, 2V

-INTRC: 7µA, 31.25 kHz, 2V

- Sleep: 0.2 µA, 2V

• Timer1 oscillator: 1.8 µA, 32 kHz, 2V

• Watchdog Timer: 0.7 µA, 2V

• Wide operating voltage range:

- Industrial: 2.0V to 5.5V

Oscillators:

• Three Crystal modes:

- LP, XT, HS: up to 20 MHz

• Two External RC modes

• One External Clock mode:

- ECIO: up to 20 MHz

• Internal oscillator block:

- 8 use r s el ec tabl e fre quenci es : 3 1 kHz, 12 5 kHz,

250kHz, 500kHz, 1MHz, 2 MHz, 4 MHz, 8 MHz

Peripheral Feat ures:

• 16 I/O pins with individual direction control

• High sink/source current: 25 mA

• Timer0: 8-bit timer/counter with 8-bit prescaler

• Ti m er1 : 1 6-b it tim er/ co un ter wi th presc a le r, can b e

incremented during Sleep via external crystal/clock

• Timer2: 8-bit timer/counter with 8-bit period

• Capture, Compare, PWM (CCP) module:

- Capture is 16-bit, max. resolution is 12.5 ns

- Compare is 16-bit, max. resolution is 200 ns

- PWM max. resolution is 10-bit

• 10-bit, 5-channel Analog-to-Digital converter

• Synchronous Serial Port (SSP) with

SPI™ (Master/Slave) and I2C™ (Slave)

Pin Diagram

Special Microcontroller Features:

• 100,000 eras e/w ri t e cycles Enhanc ed Flash

program memory typical

• 1,000,000 typical erase/write cycles EEPROM

data memory typical

• EEPROM Data Retention: > 40 years

• In-Circuit Serial ProgrammingTM (ICSPTM) via t wo pins

• Processor read/write access to program memory

• Low-Voltage Prog ramming

• In-Circuit Debugging via two pins

RA1/AN1

RA0/AN0

RA7/OSC1/CLKI

RA6/OSC2/CLKO

VDD

RB7/T1OSI/PGD

RB6/T1OSO/T1CKI/PGC

RB5/SS

RB4/SCK/SCL

RA2/AN2/VREF-

RA3/AN3/VREF+

RA4/AN4/T0CKI

RA5/MCLR/VPP

VSS

RB0/INT

RB1/SDI/SDA

RB2/SDO/CCP1

RB3/CCP1/PGM

•1

PIC16F818/819

18-Pin PD I P, SO IC

Device

Prog ram Me mory Data Memor y

I/O Pins 10-bit

A/D (ch) CCP

(PWM)

SSP Timers

8/16-bit

Flash

(Bytes) # Single-Word

Instructions SRAM

(Bytes) EEPROM

(Bytes) SPI™ Slave

I2C™

PIC16F818 1792 1024 128 128 16 5 1 Y Y 2/1

PIC16F819 3584 2048 256 256 16 5 1 Y Y 2/1

18/20-Pin Enhanced Flash Microcontrollers

with nanoWatt Technology

PIC16F818/819

DS39598E-page 2  2004 Microchip Technology Inc.

Pin Diagrams

RA1/AN1

RA0/AN0

RA7/OSC1/CLKI

RA6/OSC2/CLKO

VDD

RB7/T1OSI/PGD

RB6/T1OSO/T1CKI/PGC

RB5/SS

RB4/SCK/SCL

RA2/AN2/VREF-

RA3/AN3/VREF+

RA4/AN4/T0CKI

RA5/MCLR/VPP

VSS

RB0/INT

RB1/SDI/SDA

RB2/SDO/CCP1

RB3/CCP1/PGM

•1

18-Pin PDIP, SOIC

PIC16F818/819

RA1/AN1

RA0/AN0

RA7/OSC1/CLKI

RA6/OSC2/CLKO

VDD

RB7/T1OSI/PGD

RB6/T1OSO/T1CKI/PGC

RB5/SS

RB4/SCK/SCL

RA2/AN2/VREF-

RA3/AN3/VREF+

RA4/AN4/T0CKI

RA5/MCLR/VPP

VSS

RB0/INT

RB1/SDI/SDA

RB2/SDO/CCP1

RB3/CCP1/PGM

•1

20-Pin SSOP

10 11

VSS VDD

PIC16F818/819

28-Pin QFN

RA2/AN2/VREF-

RA0/AN0

RA4/AN4/T0CKI

RA5/MCLR/VPP

VSS

RB0/INT

RB1/SDI/SDA

RA3/AN3/VREF+

RA7/OSC1/CLKI

RA6/OSC2/CLKO

VDD

RB7/T1OSI/PGD

RB6/T1OSO/T1CKI/PGC

RB5/SS

RB4/SCK/SCL

PIC16F818/819

VSS

RA1/AN1

RB2/SDO/CCP1

RB3/CCP1/PGM

NC NC

 2004 Microchip Technology Inc. DS39598E-page 3
PIC16F818/819
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 5
2.0 Memory O rganization................................................................................................................................................................... 9
3.0 Data EEPROM and Flash Program Memory............................................................. ............... .... .............................................. 25
4.0 Oscillator Configurations............................................................................................................................................................ 33
5.0 I/O Ports................ ........................................ ................................... .......................................................................................... 39
6.0 Timer0 Module ........................................................................................................................................................................... 53
7.0 Timer1 Module ........................................................................................................................................................................... 57
8.0 Timer2 Module ........................................................................................................................................................................... 63
9.0 Capture/Compare/PWM (CCP) Module ............................................................ ...... ................. ...... ............................................ 65
10.0 Synchronous Serial Port (SSP) Module..................................................................................................................................... 71
11.0 Analog-t o-Digital Converter (A/D) Module.................................................................................................................................. 81
12.0 Specia l Features of the  CPU.................. ............................ ........................... ............................................................................. 89
13.0 Instruction Set Summary.......................................................................................................................................................... 103
14.0 Development Support............................................................................................................................................................... 111
15.0 Electrical Characteristics.......................................................................................................................................................... 117
16.0 DC and AC Characteristics Graphs and Tables.......... .... ......... .. .... .... ......... .. .... .... .... ....... .... .... .... ............................................ 143
17.0 Packagin g  In fo rmation. ................... ............................... ................................ ........................................................................... 157
Appendix A: Revision History . ............................................................................................................................................................ 163
Appendix B: Device Differences ........................................................................................................................................................ 163
Index .................................................................................................................................................................................................. 165
On-Line Support.................... .... .... .. ......... .... .. .... .. ......... .... .. .... ......... .. .... .. .... ......... .. .... .... .. ................................................................. 171
Systems Information and Upgrade Hot Line...................................................................................................................................... 171
Reader Response.............................................................................................................................................................................. 172
PIC16F818/819 Product Identification System .................................................................................................................................. 173
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PIC16F818/819

DS39598E-page 4  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 5

PIC16F818/819

1.0 DEVICE OVERVIEW

This document contains device specific information for

the operation of the PIC16F818/819 devices. Additional

information may be found in the “PICmicro® Mid-Range

MCU Family Reference Manual” (DS33023) which may

be downloaded from the Microchip web site. The

Reference Manual should be con sidered a comp lemen-

tary document to this data sheet and is highly

recommended reading for a better understanding of the

device architecture and operation of the peripheral

modules.

The PIC16F818/819 belongs to the Mid-Range family

of the PICmicro® devices. The de vice s dif f er from eac h

other in the amount of Flash program memory, data

memory and data EEPROM (see Table 1-1). A block

diagram of the devices is shown in Figure 1-1. These

devices contain features that are new to the PIC16

produ ct lin e:

• Internal RC oscillator with eight selectable

frequencies, including 31.25 kHz, 125 kHz,

250 kHz, 500 kHz, 1 MHz, 2 MHz, 4 MHz and

8 MHz. The INTRC can be configured as the

system clock via the configuration bits. Refer to

Section 4 .5 “Internal Oscillator Block” and

Section 1 2.1 “Configuration Bits” for further

details.

• The Timer1 module current consumption has

been gre atly reduc ed from 20 µA (previous PIC1 6

devi ces) to 1. 8 µA typical (32 kHz at 2V), which is

ideal for real-time clock applications. Refer to

Section 6.0 “Timer0 Module” for further details.

• The amou nt of oscillator selections has in creased.

The RC and INTRC modes can be selected with

an I/O pin configured as an I/O or a clock output

(FOSC/4). An external clock can be configured

with an I/O pin. Refer to Section 4.0 “Oscillator

Configurations” for further details.

TABLE 1-1: AVAILABLE MEMORY IN

PIC16F818/819 DEVICES

There are 16 I/O pins that are user configurable on a

pin-to-pin basis. Some pins are multiplexed with other

device functions. These functions include:

• External Inte rrupt

• Change on PORTB Interrupt

• Timer0 Clock Input

• Low-Power Timer1 Clock/Oscillator

• Capture/Compare/PWM

• 10-bit, 5-channel Anal og-to-Digi tal Converter

• SPI/I2C

•MCLR (RA5) can be configured as an Input

Table 1-2 details the pinout of the devices with

descriptions and details for each pin.

Device Program

Flash Data

Memory Data

EEPROM

PIC16F818 1K x 14 128 x 8 128 x 8

PIC16F819 2K x14 256 x 8 256 x 8

PIC16F818/819

DS39598E-page 6  2004 Microchip Technology Inc.

FIGURE 1-1: PIC16F81 8/819 BLOCK DIAGRAM

Flash

Memory

1K/2K x 14

13 Data Bus 8

Program

Bus

Instruction reg

Program Counter

8-Level Stack

(13-bit)

RAM

File

Registers

128/256 x 8

Direct Addr 7

RAM Addr(1) 9

Addr MUX

Indirect

Addr

FSR reg

Status reg

MUX

ALU

W reg

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

Instruction

Decode &

Control

Timing

Generation

RA7/OSC1/CLKI

RA6/OSC2/CLKO

MCLR VDD, VSS

Timer0

10-bit, 5-channel Synchronous

Serial Port

PORTA

Brown-out

Reset

Note 1: Higher order bits are from the Statu s registe r.

CCP1

Timer1 Timer2

RA5/MCLR/VPP

RA6/OSC2/CLKO

RA4/AN4/T0CKI

RA3/AN3/VREF+

RA2/AN2/VREF-

RA1/AN1

Program

PORTB RB0/INT

RB1/SDI/SDA

RB2/SDO/CCP1

RB3/CCP1/PGM

RB4/SCK/SCL

RB5/SS

RB6/T1OSO/T1CKI/PGC

RB7/T1OSI/PGD

RA7/OSC1/CLKI

RA0/AN0

128/256 Bytes

Data EE

A/D

 2004 Microchip Technology Inc. DS39598E-page 7

PIC16F818/819

TABLE 1-2: PIC16F818/819 PINOUT DESCRIPTIONS

Pin Name PDIP/

SOIC

Pin#

SSOP

Pin# QFN

Pin# I/O/P

Type Buffer

Type Description

PORTA is a bidirectional I/O port.

RA0/AN0

RA0

AN0

17 19 23 I/O

ITTL

Analog Bidirect ional I/O pin.

Analog input channel 0.

RA1/AN1

RA1

AN1

18 20 24 I/O

ITTL

Analog Bidirect ional I/O pin.

Analog input channel 1.

RA2/AN2/VREF-

RA2

AN2

VREF-

1126

I/O

TTL

Analog

Bidir ect ion al I/O pin.

Analog input channel 2.

A/D reference voltage (low) input.

RA3/AN3/VREF+

RA3

AN3

VREF+

2227

I/O

TTL

Analog

Bidir ect ion al I/O pin.

Analog input channel 3.

A/D reference voltage (high) input.

RA4/AN4/T0CKI

RA4

AN4

T0CKI

3328

I/O

Analog

Bidir ect ion al I/O pin.

Analog input channel 4.

Clock input to the TMR0 timer/counter.

RA5/MCLR/VPP

RA5

MCLR

VPP

441 I

–

Input pin.

Master Clear (Reset). Input/programming

voltage input. This pin is an active-low Reset

to the device.

Programming threshold voltage.

RA6/OSC2/CLKO

RA6

OSC2

CLKO

15 17 20 I/O

–

Bidir ect ion al I/O pin.

Osci llator crys tal ou tput. Connec ts to c rysta l or

resonator in Crystal Oscillator mode.

In RC mode, this pin outputs CLKO signal

which has 1/4 the frequency of OSC1 and

denotes the instruction cycle rate.

RA7/OSC1/CLKI

RA7

OSC1

CLKI

16 18 21 I/O

ST/CMOS(3)

–

Bidir ect ion al I/O pin.

Oscillator crystal input.

External clock source input.

Legend: I = Input O = Output I/O = Input/Output P = Power

– = Not used TTL = TTL Input ST = Schmitt Trigger Input

Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.

2: This buffer is a Schmitt Trigger input when used in Serial Progr amming mode.

3: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.

PIC16F818/819

DS39598E-page 8  2004 Microchip Technology Inc.

PORTB is a bidirectional I/O port. PORTB can be

softw are prog ram med fo r in tern al weak pull-up on

all inputs.

RB0/INT

RB0

INT

677

I/O

ITTL

ST(1) Bidir ect ion al I/O pin.

External interrupt pin.

RB1/SDI/SDA

RB1

SDI

SDA

788

I/O

TTL

Bidir ect ion al I/O pin.

SPI™ data in.

I2C™ data.

RB2/SDO/CCP1

RB2

SDO

CCP1

899

I/O

TTL

Bidir ect ion al I/O pin.

SPI data out.

Capture input, Compare output, PWM output.

RB3/CCP1/PGM

RB3

CCP1

PGM

91010

I/O

TTL

Bidir ect ion al I/O pin.

Capture input, Compare output, PWM output.

Low-Voltage ICSP™ Programming enable pin.

RB4/SCK/SCL

RB4

SCK

SCL

10 11 12 I/O

I/O

TTL

Bidirectional I/O pin. Interrupt-on-change pin.

Synchronous serial clock input/output for SPI.

Synchronous serial clock input for I2C.

RB5/SS

RB5

11 12 13 I/O

ITTL

TTL Bidirectional I/O pin. Interrupt-on-change pin.

Slave select for SPI in Slave mode.

RB6/T1OSO/T1CKI/PGC

RB6

T1OSO

T1CKI

PGC

12 13 15 I/O

TTL

ST(2)

Interrupt-on-change pin.

Timer1 Osci llator output.

Timer1 clock input.

In-cir cu it deb ugg er and ICSP program m ing

clock pin.

RB7/T1OSI/PGD

RB7

T1OSI

PGD

13 14 16 I/O

TTL

ST(2)

Interrupt-on-change pin.

Timer1 oscillator input.

In-cir cu it deb ugg er and ICSP program m ing

data pin.

VSS 5 5, 6 3, 5 P – Ground reference for logic and I/O pins.

VDD 14 15, 16 17, 19 P – Positive supply f or logic and I/O pins.

TABLE 1-2: PIC16F818/819 PINOUT DESCRIPTIONS (CONTINUED)

Pin Name PDIP/

SOIC

Pin#

SSOP

Pin# QFN

Pin# I/O/P

Type Buffer

Type Description

Legend: I = Input O = Output I/O = Input/Output P = Power

– = Not used TTL = TTL Input ST = Schmitt Trigger Input

Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.

2: This buffer is a Schmitt Trigger input when used in Serial Progr amming mode.

3: This buffer is a Schmitt Trigger input when configured in RC Oscillator mode and a CMOS input otherwise.

 2004 Microchip Technology Inc. DS39598E-page 9

PIC16F818/819

2.0 MEMORY ORGANIZATION

There are two memory blocks in the PIC16F818/819.

These are the program memory and the data memory.

Each block has its own bus, so access to each block

can occur during the same oscillator cycle.

The data memory can be further broken down into the

general purpose RAM and the Special Function

Registers (SFRs). The operation of the SFRs that

control the “core” are described here. The SFRs used

to control the peripheral modules are described in the

section discussing each individual peripheral module.

The data memory area also contains the data

EEPROM memory. This memory is not directly mapped

into the data memory but is indirectly mapped. That is,

an indir ect addres s pointer s peci fies th e addre ss of the

data EEPROM memory to read/write. The PIC16F818

device’ s 1 28 byt es of dat a EEPROM memo ry hav e the

address range of 00h-7Fh a nd the PIC16 F819 dev ice’s

256 byte s of dat a EEPROM memo ry hav e the add res s

range of 00h-FFh. More details on the EEPROM

memory can be found in Section 3.0 “Data EEPROM

and Flash Program Memory”.

Addit ional informat ion on devi ce memory may be found

in the “PICmicro® Mid-Range Reference Manual”

(DS33023).

FIGURE 2-1: PROGRAM MEMORY MAP

AND STACK FOR

PIC16F818

2.1 Program Memory Organization

The PIC16F818/819 devices have a 13-bit program

counter capable of addressing an 8K x 14 program

memory space. For the PIC16F818, the first 1K x 14

(0000h-03FFh) is physically implemented (see

Figure 2-1). For the PIC16F819, the first 2K x 14 is

located at 0000h-07FFh (see Figure 2-2). Accessing a

locatio n above the physic ally implem ented addres s will

cause a wraparound. For example, the same instruc-

tion will be accessed at locations 020h, 420h, 820h,

C20h, 1020h, 1420h, 1820h and 1C20h.

The Rese t v ector is a t 000 0h and t he in terrupt vecto r is

at 0004h.

FIGURE 2-2: PROGRAM MEMORY MAP

AND STACK FOR

PIC16F819

PC<12:0>

0000h

0004h

0005h

Stack Level 1

St ack Level 8

Reset Vector

Interr upt Vector

On-Chip

CALL, RETURN

RETFIE, RETLW

1FFFh

Stack Level 2

Program

Memory Page 0 03FFh

0400h

Wraps to

0000h-03FFh

PC<12:0>

0000h

0004h

0005h

Stack Level 1

St ack Level 8

Reset Vector

Interrupt Vector

On-Chip

CALL, RETURN

RETFIE, RETLW

1FFFh

Stack Level 2

Program

Memory Page 0

07FFh

0800h

Wraps to

0000h-07FFh

PIC16F818/819

DS39598E-page 10  2004 Microchip Technology Inc.

2.2 Data Memory Organization

The dat a memory is p arti tioned into m ultip le ban ks th at

cont ain the Genera l Purpose Regis ters and the Spe cial

Function Registers. Bits RP1 (Status<6>) and RP0

(Status<5>) are the bank select bits.

Each bank extends up to 7Fh (128 bytes). The lower

locations of each bank are reserved for the Special

Functio n Register s. Above the Spe cial Function Regis-

ters are the Genera l Purpos e Regist ers, imp lement ed

as static RAM. All implemented banks contain SFRs.

Some “high use” SFRs from one bank may be mirrored

in another bank for code reduction and quicker access

(e.g., the Status register is in Banks 0-3).

2.2. 1 GENERAL PURP OSE REGISTER

FILE

The register file can be accessed either directly or

indirectly through the File Select Register, FSR.

RP1:RP0 Bank

00 0

01 1

10 2

11 3

Note: EEPROM dat a memory description can be

found in Section 3.0 “Dat a EEPROM a nd

Flash Program Memory” of this data

sheet.

 2004 Microchip Technology Inc. DS39598E-page 11

PIC16F818/819

FIGURE 2-3: PIC16F818 REGISTER FILE MAP

Indirect addr.(*)

TMR0

PCL

STATUS

FSR

PORTA

PORTB

PCLATH

INTCON

PIR1

TMR1L

TMR1H

T1CON

TMR2

T2CON

SSPBUF

SSPCON

CCPR1L

CCPR1H

CCP1CON

OPTION_REG

PCL

STATUS

FSR

TRISA

TRISB

PCLATH

INTCON

PIE1

PCON

PR2

SSPSTAT

00h

01h

02h

03h

04h

05h

06h

07h

08h

09h

0Ah

0Bh

0Ch

0Dh

0Eh

0Fh

10h

11h

12h

13h

14h

15h

16h

17h

18h

19h

1Ah

1Bh

1Ch

1Dh

1Eh

1Fh

80h

81h

82h

83h

84h

85h

86h

87h

88h

89h

8Ah

8Bh

8Ch

8Dh

8Eh

8Fh

90h

91h

92h

93h

94h

95h

96h

97h

98h

99h

9Ah

9Bh

9Ch

9Dh

9Eh

9Fh

20h A0h

7Fh FFh

Bank 0 Bank 1

File

Address

Indirect addr.(*) Indirect add r.(*)

PCL

STATUS

FSR

PCLATH

INTCON

PCL

STATUS

FSR

PCLATH

INTCON

100h

101h

102h

103h

104h

105h

106h

107h

108h

109h

10Ah

10Bh

180h

181h

182h

183h

184h

185h

186h

187h

188h

189h

18Ah

18Bh

17Fh 1FFh

Bank 2 Bank 3

Indirect addr.(*)

TMR0 OPTION_REG

ADRESH

ADCON0 ADCON1

General

Purpose

20h-7Fh

TRISB

PORTB

96 Bytes

10Ch

10Dh

10Eh

10Fh

110h

18Ch

18Dh

18Eh

18Fh

190h

EEDATA

EEADR EECON1

EEDATH

EEADRH

Unimplemented data memory locations, read as ‘0’.

* Not a physical register.

Note 1: These registers are reserved; maintain these registers clear.

File

Address

File

Address

File

Address

SSPADD

120h

11Fh 1A0h

19Fh

General

Purpose

32 Bytes BFh

C0h

Accesses

40h-7Fh

Accesses

20h-7Fh

PIR2 PIE2

OSCCON

OSCTUNE

ADRESL

EECON2

Reserved(1)

PIC16F818/819

DS39598E-page 12  2004 Microchip Technology Inc.

FIGURE 2-4: PIC16F819 REGISTER FILE MAP

Indirect addr.(*)

TMR0

PCL

STATUS

FSR

PORTA

PORTB

PCLATH

INTCON

PIR1

TMR1L

TMR1H

T1CON

TMR2

T2CON

SSPBUF

SSPCON

CCPR1L

CCPR1H

CCP1CON

OPTION_REG

PCL

STATUS

FSR

TRISA

TRISB

PCLATH

INTCON

PIE1

PCON

PR2

SSPSTAT

00h

01h

02h

03h

04h

05h

06h

07h

08h

09h

0Ah

0Bh

0Ch

0Dh

0Eh

0Fh

10h

11h

12h

13h

14h

15h

16h

17h

18h

19h

1Ah

1Bh

1Ch

1Dh

1Eh

1Fh

80h

81h

82h

83h

84h

85h

86h

87h

88h

89h

8Ah

8Bh

8Ch

8Dh

8Eh

8Fh

90h

91h

92h

93h

94h

95h

96h

97h

98h

99h

9Ah

9Bh

9Ch

9Dh

9Eh

9Fh

20h A0h

7Fh FFh

Bank 0 Bank 1

File

Address

Indirect addr.(*) Indirect add r.(*)

PCL

STATUS

FSR

PCLATH

INTCON

PCL

STATUS

FSR

PCLATH

INTCON

100h

101h

102h

103h

104h

105h

106h

107h

108h

109h

10Ah

10Bh

180h

181h

182h

183h

184h

185h

186h

187h

188h

189h

18Ah

18Bh

17Fh 1FFh

Bank 2 Bank 3

Indirect addr.(*)

TMR0 OPTION_REG

ADRESH

ADCON0 ADCON1

General

Purpose

TRISB

PORTB

96 Bytes

10Ch

10Dh

10Eh

10Fh

110h

18Ch

18Dh

18Eh

18Fh

190h

EEDATA

EEADR EECON1

EEDATH

EEADRH

Unimplemented data memory locations, read as ‘0’.

* Not a physical register.

Note 1: These registers are reserved; maintain these registers clear.

File

Address

File

Address

File

Address

SSPADD

120h

11Fh 1A0h

19Fh

General

Purpose

80 Bytes

EFh

F0h

Accesses

70h-7Fh

Accesses

20h-7Fh

PIR2 PIE2

OSCCON

OSCTUNE

ADRESL

EECON2

Reserved(1)

16Fh

170h

Accesses

70h-7Fh

General

Purpose

80 Bytes

 2004 Microchip Technology Inc. DS39598E-page 13
PIC16F818/819
2.2.2 SPECIAL FUNCTION REGISTERS
The Special Function Registers are registers used by
the CPU and peripheral modules for controlling the
desired operation of the device. These registers are
implemented as static RAM. A list of these registers is
given in Table 2-1.
The Special Function Registers can be classified into
two sets: core (CPU) and peripheral. Those registers
associated with the core functions are described in
detail in this section. Those related to the operation of
the peripheral features are described in detail in the
peripheral feature section.
TABLE 2-1: 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 Details on 
page:
   Bank 0
00h(1) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 23
01h TMR0 Timer0 Module Register xxxx xxxx 53, 17
02h(1) PCL Program Counter’s (PC) Least Significant Byte 0000 0000 23
03h(1) STATUS IRP RP1 RP0 TO PD Z DC C 0001 1xxx 16
04h(1) FSR Indirect Data Memory Address Pointer xxxx xxxx 23
05h PORTA PORTA Data Latch when written; PORTA pins when read xxx0 0000 39
06h PORTB PORTB Data Latch when written; PORTB pins when read xxxx xxxx 43
07h —Unimplemented — —
08h —Unimplemented — —
09h —Unimplemented — —
0Ah(1,2) PCLATH — — — Write Buffer for the upper 5 bits of the Program Counter ---0 0000 23
0Bh(1) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 18
0Ch PIR1 —ADIF —— SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 20
0Dh PIR2 — — — EEIF — — — — ---0 ---- 21
0Eh TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx 57
0Fh TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx 57
10h T1CON —— T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 57
11h TMR2 Timer2 Module Register 0000 0000 63
12h T2CON — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 64
13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx 71, 76
14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 73
15h CCPR1L Capture/Compare/PWM Register (LSB) xxxx xxxx 66, 67, 68
16h CCPR1H Capture/Compare/PWM Register (MSB) xxxx xxxx 66, 67, 68
17h CCP1CON —— CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 65
18h —Unimplemented — —
19h —Unimplemented — —
1Ah —Unimplemented — —
1Bh —Unimplemented — —
1Ch —Unimplemented — —
1Dh —Unimplemented — —
1Eh ADRESH A/D Result Register High Byte xxxx xxxx 81
1Fh ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE —ADON0000 00-0 81
Legend: x = unknown,  u = unchanged, q = value depends on condition, - = unimplemented, read as ‘0’, r = res erved. 
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8>, whose contents are 
transferred to the upper byte of the program counter.
3: Pin 5 is an input only; the state of the TRISA5 bit has no effect and will always read ‘1’.

PIC16F818/819
DS39598E-page 14  2004 Microchip Technology Inc.
   Bank 1
80h(1) INDF Addressing this location uses contents of FSR to address data memory (not a physical register) 0000 0000 23
81h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 17, 54
82h(1) PCL Program Counter’s (PC) Least Significant Byte 0000 0000 23
83h(1) STATUS IRP RP1 RP0 TO PD ZDCC0001 1xxx 16
84h(1) FSR Indirect Data Memory Address Pointer xxxx xxxx 23
85h TRISA TRISA7 TRISA6 TRISA5(3) PORTA Data Direction Register (TRISA<4:0> 1111 1111 39
86h TRISB PORTB Data Direction Register 1111 1111 43
87h —Unimplemented — —
88h —Unimplemented — —
89h —Unimplemented — —
8Ah(1,2) PCLATH — — — Write Buffer for the upper 5 bits of the PC ---0 0000 23
8Bh(1) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 18
8Ch PIE1 —ADIE —— SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 19
8Dh PIE2 — — — EEIE — — — — ---0 ---- 21
8Eh PCON — — — — — —PORBOR ---- --qq 22
8Fh OSCCON — IRCF2 IRCF1 IRCF0 — IOFS — — -000 -0-- 38
90h(1) OSCTUNE —— TUN5 TUN4 TUN3 TUN2 TUN1 TUN0 --00 0000 36
91h —Unimplemented — —
92h PR2 Timer2 Peri o d Regi ste r 1111 1111 68
93h SSPADD Synchronous Serial Port (I2C™ mode) Address Register 0000 0000 71, 76
94h SSPSTAT SMP CKE D/A PSR/WUA BF 0000 0000 72
95h —Unimplemented — —
96h —Unimplemented — —
97h —Unimplemented — —
98h —Unimplemented — —
99h —Unimplemented — —
9Ah —Unimplemented — —
9Bh —Unimplemented — —
9Ch —Unimplemented — —
9Dh —Unimplemented — —
9Eh ADRESL A/D Result Register Low Byte xxxx xxxx 81
9Fh ADCON1 ADFM ADCS2 —— PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 82
TABLE 2-1: 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 Details on 
page:
Legend: x = unknown,  u = unchanged, q = value depends on condition, - = unimplemented, read as ‘0’, r = res erved. 
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8>, whose contents are 
transferred to the upper byte of the program counter.
3: Pin 5 is an input only; the state of the TRISA5 bit has no effect and will always read ‘1’.

 2004 Microchip Technology Inc. DS39598E-page 15
PIC16F818/819
   Bank 2
100h(1) I NDF Addressing this location uses contents of FSR to address data memory (not a physi cal regi ster) 0000 0000 23
101h TMR0 Timer0 Module Register xxxx xxxx 53
102h(1 PC L Program Counter’s (PC) Least Significant Byte 0000 0000 23
103h(1) STATUS IRP RP1 RP0 TO PD ZDCC0001 1xxx 16
104h(1) FSR Indirect Dat a Memory Address Point er xxxx xxxx 23
105h —Unimplemented — —
106h PORTB PORTB D ata Latch when written; PORTB pins when read xxxx xxxx 43
107h —Unimplemented — —
108h —Unimplemented — —
109h —Unimplemented — —
10Ah(1,2) PCLATH — — — Write Buffer for the upper 5 bits of  the Program Counter ---0 0000 23
10Bh(1) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 18
10Ch EEDATA EEPROM/Flash Data Register Low Byte xxxx xxxx 25
10Dh EEADR EEPROM/Flash Address Register Low Byte xxxx xxxx 25
10Eh EEDATH —— EEPROM/Flash Data Register High Byte --xx xxxx 25
10Fh EEADRH — — — — — EEPROM /F lash A ddr ess Regist er 
Hig h Byte ---- -xxx 25
   Bank  3
180h(1) I NDF Addressing this location uses contents of FSR to address data memory (not a physi cal regi ster) 0000 0000 23
181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 17, 54
182h(1) PCL Program Co unter’s (PC) Least Significant Byte 0000 0000 23
183h(1) STATUS IRP RP1 RP0 TO PD ZDCC0001 1xxx 16
184h(1) FSR Indirect Dat a Memory Address Point er xxxx xxxx 23
185h —Unimplemented — —
186h TRISB PORTB Data Direction Register 1111 1111 43
187h —Unimplemented — —
188h —Unimplemented — —
189h —Unimplemented — —
18Ah(1,2) PCLATH — — — Write Buffer for the upper 5 bits of  the Program Counter ---0 0000 23
18Bh(1) INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 18
18Ch EECON1 EEPGD —— FREE WRERR WREN WR RD x--x x000 26
18Dh EECON2 EEPROM Control Register 2 (not a physical register) ---- ---- 25
18Eh —Reserved; mai nt ain cl ear 0000 0000 —
18Fh —Reserved; maint ai n clear 0000 0000 —
TABLE 2-1: 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 Details on 
page:
Legend: x = unknown,  u = unchanged, q = value depends on condition, - = unimplemented, read as ‘0’, r = res erved. 
Shaded locations are unimplemented, read as ‘0’.
Note 1: These registers can be addressed from any bank.
2: The upper byte of the program counter is not directly accessible. PCLATH is a holding register for the PC<12:8>, whose contents are 
transferred to the upper byte of the program counter.
3: Pin 5 is an input only; the state of the TRISA5 bit has no effect and will always read ‘1’.

PIC16F818/819

DS39598E-page 16  2004 Microchip Technology Inc.

2.2.2.1 Status Register

The S tatus register , shown in Register 2-1, contains the

arit hmeti c statu s of th e ALU, the Re set sta tus an d the

bank select bits for data memory.

The Status register can be the destination for any

instruction, as with any other register. If the Status

the Z, DC or C bits, then the write to these three bits is

disabl ed. These bit s are set or clea red 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 exam pl e, CLRF STATUS, will c lea r the up per three

bits and set th e Z bit. Thi s leaves the Status re gister as

‘000u u1uu’ (where u = unchanged).

It is recommended, therefore, that only BCF, BSF,

SWAPF and MOVWF instructions are used to alter the

S t atus regis ter becaus e these inst ructions do not affec t

the Z, C or DC bits from the Status register. For other

instructions not affecting any status bits, see

Section 1 3.0 “Instruction Set Summary”.

Note: The C and DC bits operate as a borrow

and digit borrow bit, respectively, in

subtraction. See the SUBLW and SUBWF

instructions for examples.

R/W-0 R/W-0 R/W-0 R-1 R-1 R/W-x R/W-x R/W-x

IRP RP1 RP0 TO PD ZDCC

bit 7 bit 0

bit 7 IRP: Register Bank Select bit (used for indirect addressing)

1 = Bank 2, 3 (100h-1FFh)

0 = Bank 0, 1 (00h-FFh)

bit 6-5 RP<1:0>: Register Bank Select bits (used for direct addressing)

11 = Bank 3 (180h-1FF h)

10 = Bank 2 (100h-17Fh)

01 = Bank 1 (80h-FFh)

00 = Bank 0 (00h-7Fh)

Each bank is 128 bytes.

bit 4 TO: Time-out bit

1 = After power-up, CLRWDT instruction or SLEEP instru cti on

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 instru cti on

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/borrow bit (ADDWF, ADDLW, SUBLW and SUBWF ins tru cti ons )(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 (ADDWF, ADDLW, SUBLW and SUBWF instructions)(1,2)

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.

2: For rotate (RRF, RLF) instructions , this bi t is loaded with e ither the hig h or low -order

bit of the source register.

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 17

PIC16F818/819

2.2.2.2 OPTION_REG Regi st er

The OPTION_REG register is a readable and writable

the TMR0 prescaler/WDT postscaler (single assign-

able register known also as the prescaler), the external

INT interrupt , TMR0 and the weak pull-u ps on PORTB.

Note: To achieve a 1:1 prescaler assignment for

the TMR 0 re gist er, assign the pr escaler to

the Watchdog Timer.

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0

bit 7 bit 0

bit 7 RBPU: PORTB Pull -up Enab le bit

1 = PORTB pull-ups are disabled

0 = PORTB pull-ups are enabled by individual port latch values

bit 6 INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of RB0/INT pin

0 = Interrupt on falling edge of RB0/INT pin

bit 5 T0CS: TMR0 Clock Source Select bit

1 = Transition on T0CKI pin

0 = Internal instruction cycle clock (CLKO)

bit 4 T0SE: TMR0 Source Edge Select bit

1 = Increment on hig h-to -low trans it ion on T0CKI pin

0 = Increment on low- to -hi gh trans it ion on T0CKI pin

bit 3 PSA: Prescaler Assign me nt bit

1 = Prescaler is assigned to the WDT

0 = Prescaler is assigned to the Timer0 module

bit 2-0 PS2:PS0: Presca ler Rate Sele ct bits

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

000

001

010

011

100

101

110

111

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

1 : 256

1 : 1

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

Bit Value TMR0 Rate WDT Rate

PIC16F818/819

DS39598E-page 18  2004 Microchip Technology Inc.

2.2.2.3 INTCON Register

The INTCON register is a readable and writable regis-

ter that contains various enable and flag bits for the

TMR0 register overflow, RB port change and external

RB0/INT pin interrupts.

Note: Interru pt flag bit s get set when an interru pt

conditi on oc curs regard le ss of the sta te of

its corresponding enable bit or the Global

Interrupt Enable bit, GIE (INTCON<7>).

User so ftware sh ould ensu re the approp ri-

ate interrupt flag bits are clear prior to

enabling an interrupt.

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-x

GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF

bit 7 bit 0

bit 7 GIE: Global Interrupt Enable bit

1 = Enables all unmasked interrupts

0 = Disables all interrupts

bit 6 PEIE: Peripheral Interrupt Enable bit

1 = Enables all unmasked peripheral interrupts

0 = Disables all peripheral interrupts

bit 5 TMR0IE: TMR0 Overflow Interrupt Enable bit

1 = Enables the TMR0 interrupt

0 = Disables the TMR0 interru pt

bit 4 INTE: RB0/INT External Interrupt Enable bit

1 = Enables the RB0/INT external interrupt

0 = Disables the RB0/INT external inte rrup t

bit 3 RBIE: RB Port Change Interrupt Enable bit

1 = Enables the RB port change interrupt

0 = Disables the RB port change interrupt

bit 2 TMR0IF: TMR0 Overflow Interrupt Flag bit

1 = TMR0 register has overflowed (must be cleared in software)

0 = TMR0 register did not overflow

bit 1 INTF: RB0/INT External Interrupt Flag bit

1 = The RB0/INT external interrupt occurred (must be cleared in software)

0 = The RB0/INT external interrupt did not occur

bit 0 RBIF: RB Port Change Interrupt Flag bit

A mismat ch condi tio n w il l c on tin ue to s et fla g bit RBI F. Reading PORTB will end th e m isma tch

co ndition and allow flag bi t RBIF to be cleared.

1 = At least one of the RB7:RB4 pins changed state (must be cleared in software)

0 = None of the RB7:RB4 pins have changed state

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 19

PIC16F818/819

2.2.2.4 PIE1 Regi st er

This register contains the individual enable bits for the

peripheral interrupts.

Note: Bit PEIE (INTCON<6>) must be set to

enable any peripheral interrupt.

U-0 R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0

—ADIE—— SSPIE CCP1IE TMR2IE TMR1IE

bit 7 bit 0

bit 7 Unimplemented: Read as ‘0’

bit 6 ADIE: A/D Converter Interrupt Enable bit

1 = Enables the A/D converter interrupt

0 = Disables the A/D converter interrupt

bit 5-4 Unimplemented: Read as ‘0’

bit 3 SSPIE: Synchronous Serial Port Interrupt Enable bit

1 = Enables the SSP interrupt

0 = Disables the SSP 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 TMR2 to PR2 match interrupt

0 = Disables the TMR2 to PR2 match interrupt

bit 0 TMR1IE: TMR1 Overflow Interrupt Enable bit

1 = Enables the TMR1 overflow interrupt

0 = Disables the TMR1 overflow interrupt

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PIC16F818/819

DS39598E-page 20  2004 Microchip Technology Inc.

2.2.2.5 PIR1 Register

This register contains the individual flag bits for the

peripheral interrupts.

Note: Interru pt flag bi ts are set when an interrupt

conditi on oc curs regard le ss of the sta te of

its corresponding enable bit or the Global

Interrupt Enable bit, GIE (INTCON<7>).

User so ftware sh ould ensu re the approp ri-

ate interrupt flag bits are clear prior to

enabling an interrupt.

U-0 R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0

—ADIF—— SSPIF CCP1IF TMR2IF TMR1IF

bit 7 bit 0

bit 7 Unimplemented: Read as ‘0’

bit 6 ADIF: A/D Converter Interrupt Flag bit

1 = An A/D conversion completed

0 = The A/D conversion is not complete

bit 5-4 Unimplemented: Read as ‘0’

bit 3 SSPIF: Synchronous Serial Port (SSP) Interrupt Flag bit

1 = The SSP interrupt condition has occurred and must be cleare d in software before returnin g

fro m t he I n t err u pt S erv ic e R out i ne . T h e co nd iti o ns t hat wil l s et t hi s b i t a re a t ran sm is si on /

reception has taken place.

0 = No SSP interrupt condition has occurred

bit 2 CCP1IF: CCP1 Interrupt Flag bit

Capture mode:

1 = A TMR1 register capture occurred (must be cleared in software)

0 = No TM R1 register capture occurred

Compare mode:

1 = A TMR1 register compare match occurred (must be cleared in software)

0 = No TMR1 register compare match occurred

PWM mode:

Unused in this mode .

bit 1 TMR2IF: TMR2 to PR2 Match Interrupt Flag bit

1 = TMR2 to PR2 match occurred (must be cleared in software)

0 = No TMR2 to PR2 match occurred

bit 0 TMR1IF: TMR1 Overflow Interrupt Flag bit

1 = TMR1 register overflow ed (must be clear ed in software)

0 = TMR1 register did not overflow

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 21

PIC16F818/819

2.2.2.6 PIE2 Regi st er

The PIE2 register contains the individual enable bit for

the EEPROM write operation interrupt.

2.2.2.7 PIR2 Register

The PIR2 regis ter contains the flag bit for the EEPROM

write operation interrupt.

U-0 U-0 U-0 R/W-0 U-0 U-0 U-0 U-0

— — — EEIE — — — —

bit 7 bit 0

bit 7-5 Unimplemented: Read as ‘0’

bit 4 EEIE: EEPROM Write Operation Interrupt Enable bit

1 = Enable EE write interrupt

0 = Disable EE write i nter rupt

bit 3-0 Unimplemented: Read as ‘0’

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

Note: Interru pt flag bi ts are set when an interrupt

conditi on occ urs regard les s of the sta te of

its corresponding enable bit or the Global

Interrupt Enable bit, GIE (INTCON<7>).

User so ftware sh ould ensu re the approp ri-

ate interrupt flag bits are clear prior to

enabling an interrupt.

U-0 U-0 U-0 R/W-0 U-0 U-0 U-0 U-0

— — — EEIF — — — —

bit 7 bit 0

bit 7-5 Unimplemented: Read as ‘0’

bit 4 EEIF: EEPROM Write Operation Interrupt Enable bit

1 = Enable EE write interrupt

0 = Disable EE write i nter rupt

bit 3-0 Unimplemented: Read as ‘0’

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PIC16F818/819

DS39598E-page 22  2004 Microchip Technology Inc.

2.2.2.8 PCON Regist er

The Power Control (PCON) register contains a flag bit

to allow differentiation between a Power-on Reset

(POR), a Brown-out Reset, an external MCLR Reset

and WDT Reset.

Note: Interru pt flag bit s get set when an interru pt

condition occurs regardless of the state of

its corresponding enable bit or the Global

Interrupt Enable bit, GIE (INTCON<7>).

User softw are shoul d ensure th e appropri-

ate interrupt flag bits are clear prior to

enabling an interrupt.

Note: BOR is unknown on Power-on Reset. It

must the n be set b y th e us er an d c hec ke d

on subsequent Resets to see if BOR is

clear , indicating a brown-out has occurred.

The BOR status bit is a ‘don’t care’ and is

not necessarily predictable if the brown-

out circuit is disabled (by clearing the

BOREN bit in the Configuration word).

U-0 U-0 U-0 U-0 U-0 U-0 R/W-0 R/W-x

— — — — — —PORBOR

bit 7 bit 0

bit 7-2 Unimplemented: R e ad as ‘0’

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 Brown-out Reset occurs)

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 23

PIC16F818/819

2.3 PCL and PCLATH

The Program Counter (PC) is 13 bits wide. The low

byte comes from the PCL register, which is a readable

and writable register. The upper bits (PC<12:8>) are

not readable but are indirectly writable through the

PCLATH register. On any Reset, the upper bits of the

PC will b e clea red. Fig ure 2-5 show s the two situat ion s

for the loading of the PC. The upper example in the

figure shows how the PC is loaded on a write to PCL

(PCLATH<4:0> → PCH). The lower example in the

figure shows how the PC is loaded during a CALL or

GOTO instructi on (PCLATH<4:3> → PCH).

FIGURE 2-5: LOADING OF PC IN

DIFFERENT SITUATIONS

2.3.1 COMPUTED GOTO

A comput ed GOTO is a ccom pli shed by a ddi ng an offset

to the program counter (ADDWF PCL). When doing a

table read using a computed GOTO method, care

should be ex ercise d if th e t able loca tion c rosse s a PCL

memory boundary (each 256-byte block). Refer to the

application note AN556, “Implementing a Table Read”

(DS00556).

2.3.2 STACK

The PI C16F818/ 819 family h as an 8-leve l deep x 13-b it

wide hardware stack. The stack space is not part of

either program or data space and the Stack Pointer is

not readable or writable. The PC is PUSHed onto the

stack when a CALL instruction is 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 st ack operates as a circular buffer . This means that

after the stack has been PUSHed eight times, the ninth

push ove rwrite s the va lue tha t was s tored fro m the firs t

push. The tenth push ov erwr i tes the se cond pus h (an d

so on).

2.4 Indirect Addressing: INDF and

FSR Registers

The INDF register is no t a physical reg ister . Addr essing

INDF actu ally ad dresse s the regi ster w hose ad dress i s

cont ained in the FSR reg ister (FSR is a pointer). This is

indirect addressing.

EXAMPLE 2-1: INDIR ECT ADDRESS ING

Reading INDF itself indirectly (FSR = 0) will produce

00h. Writing to the INDF register indirectly results in a

no operation (although status bits may be affected).

A simple program to clear RAM locations, 20h-2Fh,

using indirect addressing is shown in Example 2-2.

EXAMPLE 2-2: HOW TO CLEAR RAM

USING INDIRECT

ADDRESSING

An ef fect ive 9-b it addre ss is obt ain ed b y conca tenatin g

the 8-bit FSR register and the IRP bit (Status<7>) as

shown in Figure 2-6.

12 8 7 0

5PCLATH<4:0>

PCLATH

Instruction with

ALU

GOTO,CALL

Opcode < 10:0 >

12 11 10 0

PCLATH<4:3>

PCH PCL

PCLATH

PCH PCL

PCL as

Destination

Note 1: There are no status bits to indicate stack

overflow or stack underflow conditions.

2: There are no instructions/mnemonics

called PUSH or POP. These are actions

that occur from the execution of the

CALL, RETURN, RETLW and RETFIE

instructions or the vectoring to an

interr upt add ress.

• Register file 05 contains the value 10h

• Register file 06 contains the value 0Ah

• Load the value 05 into the FSR register

• A read of th e IND F r egi ste r will ret urn the val ue

of 10h

• Increment the value of the FSR register by one

(FSR = 06)

• A read of the INDF register now will return the

value of 0Ah

MOVLW 0x20 ;initialize pointer

MOVWF FSR ;to RAM

NEXT CLRF INDF ;clear INDF register

INCF FSR ;inc pointer

BTFSS FSR, 4 ;all done?

GOTO NEXT ;NO, clear next

CONTINUE

: ;YES, continue

PIC16F818/819

DS39598E-page 24  2004 Microchip Technology Inc.

FIGURE 2-6: DIRECT/INDI RECT ADDRESSING

Note 1: For register file map det ail, see Figure 2-3 or Figure 2-4.

Data

Memory(1)

Indirect AddressingDirect Addressing

Bank Select Locat ion Select

RP1:RP0 6 0

From Opcode IRP FSR Register

Bank Select Location Select

00 01 10 11

Bank 0 Bank 1 Bank 2 Bank 3

FFh

80h

7Fh

00h

17Fh

100h

1FFh

180h

 2004 Microchip Technology Inc. DS39598E-page 25

PIC16F818/819

3.0 DATA EEPROM AND FLASH

PROGRAM MEMORY

The data EEPROM and Flash program memory are

readable and writable during normal operation (over

the full VDD range). Thi s memory is not directly mapped

in the register file space. Instead, it is indirectly

addressed through the Special Function Registers.

There are six SFRs used to read and write this

memory:

• EECON1

• EECON2

• EEDATA

• EEDATH

• EEADR

• EEADRH

This section focuses on reading and writing data

EEPROM and Flash program memory during normal

operation. Refer to the appropriate device program-

ming specification document for serial programming

information.

When interfacing the data memory block, EEDATA

holds the 8-bit data for read/write and EEADR h olds the

address of the EEPROM location being accessed.

These devices have 128 or 256 bytes of data

EEPROM, with an address range from 00h to 0FFh.

Addresses from 80h to FFh are unimplemented on the

PIC16F818 device and will read 00h. When writing to

unimplemented locations, the charge pump will be

turned off.

When interfacing the program memory block, the

EEDATA and EEDATH registers form a two-byte word

that holds the 14-bit data for read/wr ite and the EEADR

and EEA DRH regi sters form a two -byte word th at holds

the 13-bit address of the EEPROM location being

accessed. These devices have 1K or 2K words of

program Flash, with an address range from 0000h to

03FFh for the PIC16F818 and 0000h to 07FFh for the

PIC16F8 19. Add resse s abov e the range of the respe c-

tive dev ice will wra paround to t he beginning o f program

memory.

The EEPROM data memory allows single byte read

and write. The Flash program memory allows single-

word reads and four-word block writes. Program

memory writes must first start with a 32-word block

erase, then write in 4-word blocks. A byte write in data

EEPROM memory automatically erases the location

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.

When the device is code-protected, the CPU may

continu e to rea d and wr ite th e data EEPROM memory.

Depending on the settings of the write-protect bits, the

device may or may not be able to write certain blocks

of the program memory; however , reads of the program

memory are allowed. Whe n code-prote cted, the dev ice

programmer can no longer access data or program

memory; thi s d oes NOT inh ib it in tern al re ad s or w ri tes .

3.1 EEADR and EEADRH

The EEADRH:EEADR register pair can address up to

a maximum of 256 bytes of data EEPROM or up to a

maximum of 8K words of program EEPROM. When

selecting a data address value, only the LSB of the

address is writte n to the EEADR regi ster. When select-

ing a program address value, the MSB of the address

is written to the EEADRH register and the LSB is

written to the EEADR register.

If the device co ntains less memo ry than the full address

reach of the address register pair, the Most Significant

bits of the reg isters are not im plem ented. F or exam ple,

if the de vi ce has 128 byte s o f da t a EEPROM, th e M os t

Signific ant bit of EEADR i s not impl ement ed on a cces s

to data EEPROM.

3.2 EECON1 and EECON2 Registers

EECON1 is the control register for memory accesses.

Control bit, EEPGD, determines if the access will be a

program or data memory access. When clear, as it is

when Reset, any subsequent operations will operate

on the data memory. When set, any subsequent

operations will operate on the program memory.

Control bits, RD and WR, initiate read and write,

resp ectivel y. These bits cannot be cleare d, 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 or erase

operation. On power-up, the WREN bit is clear. The

WRERR bit is set when a write (or erase) operation is

interrupted by a MCLR or a WDT Time-out Reset

during normal operation. In these situations, following

Reset, the user can check the WRERR bit and rewrite

the location. The data and address will be unchanged

in the EEDATA and EEADR registers.

Interrupt flag bit, EEIF in the PIR2 register, is set when

the write is complete. It must be cleared in software.

EECON2 is not a physical register. Reading EECON2

will read all ‘0’s. The EECON2 register is used

exclusively in the EEPROM write sequence.

PIC16F818/819

DS39598E-page 26  2004 Microchip Technology Inc.

R/W-x U-0 U-0 R/W-x R/W-x R/W-0 R/S-0 R/S-0

EEPGD —— FREE WRERR WREN WR RD

bit 7 bit 0

bit 7 EEPGD: Program/Data EEPROM Select bit

1 = Accesses program memory

0 = Accesses data memory

Reads ‘0’ after a POR; this bit cannot be changed while a write operation is in progress.

bit 6-5 Unimplemented: Read as ‘0’

bit 4 FREE: EEPROM Forced Row Erase bit

1 = Erase t he program memory row a ddressed by EEADRH:EEADR on th e next WR command

0 = Perform write-only

bit 3 WRERR: EEPROM Error Flag bit

1 = A write operation is prematurely terminated (any MCLR or any WDT Reset during normal

operation)

0 = The write operation completed

bit 2 WREN: EEPROM Write Enable bit

1 = Allows write cycles

0 = Inhibits write to the EEPROM

bit 1 WR: Write Control bit

1 = Initiates a write cycle. The bit is cleared by hardware once write is complete. The WR bit

can only be set (not cleared) in software.

0 = Write cycle to the EEPROM is complete

bit 0 RD: Read Control bit

1 = Initiates an EEPROM read, RD is cleared in hardware. The RD bit can only be set (not

cleared) in software.

0 = Does not initiate an EEPROM read

Legend:

R = Readable bit W = Writable bit S = Set only U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 27

PIC16F818/819

3.3 Reading Data EEPROM Memory

To read a data memory loca tion, the user must write the

address to the EEADR register, clear the EEPGD

control bit (EECON1<7>) and then set control bit, RD

(EECON1<0>). The data is available in the very next

cycle in the EEDATA register; therefore, it can be read

in the next instruction (see Example 3-1). EEDATA will

hold this value until another read or until it is written to

by the user (during a write operation).

The steps to reading the EEPROM data memory are:

1. Write the address to EEADR. Make sure that the

address is not larger than the memory size of

the device.

2. Clear the EEPGD bit to point to EEPROM data

memory.

3. Set the RD bit to start the read operation.

4. Read the data from the EE DATA register.

EXAMPLE 3-1: DATA EEPROM READ

3.4 Writing to Data EEPROM Memory

To write an EEPROM data location, the user must first

write the address to the EEADR register and the data

to the EEDATA register. Then, the user must follow a

specific write sequence to initiate the write for each

byte.

The write will not initiate if the write sequence is not

exactly followed (write 55h to EECON2, write AAh to

EECON2, then set WR bit) for each byte. We strongly

recommend that interrupts be disabled during this

code segment (see Example 3-2).

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 wil l not af fect this wri te cycle. T he 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 b y softwar e.

The steps to write to EEPROM data memory are:

1. If step 10 is not implemented, check the WR bit

to see if a write is in progress.

2. Write the address to EEADR. Make sure that the

address is not larger than the memory size of

the device.

3. Write the 8-bit data value to be programmed in

the EEDATA register.

4. Clear the EEPGD bit to point to EEPROM data

memory.

5. Set the WREN bit to en able program operations.

6. Disable interrupts (if enabled).

7. Execute the special five instruction sequence:

• Write 55h to EECON2 in two steps (first to W,

then to EECON2)

• Write AAh to EECON2 in two steps (first to W,

then to EECON2)

• Set the WR bit

8. Enable interrupts (if using interrupts).

9. Clear the WREN bit to disable program

operations.

10. At the completion of the write cycle, the WR bit

is cleared and the EEIF interrupt flag bit is set

(EEIF must be cleared by firmware). If step 1 is

not implemented, then firmware should check

for EEIF to b e s et, or W R to b e cle ar, to i ndi ca te

the end of the program cycle.

EXAMPLE 3-2: DATA EEPROM WRITE

BANKSEL EEADR ; Select Bank of EEADR

MOVF ADDR, W ;

MOVWF EEADR ; Data Memory Address

; to read

BANKSEL EECON1 ; Select Bank of EECON1

BCF EECON1, EEPGD ; Point to Data memory

BSF EECON1, RD ; EE Read

BANKSEL EEDATA ; Select Bank of EEDATA

MOVF EEDATA, W ; W = EEDATA

BANKSEL EECON1 ; Select Bank of

; EECON1

BTFSC EECON1, WR ; Wait for write

GOTO $-1 ; to complete

BANKSEL EEADR ; Select Bank of

; EEADR

MOVF ADDR, W ;

MOVWF EEADR ; Data Memory

; Address to write

MOVF VALUE, W ;

MOVWF EEDATA ; Data Memory Value

; to write

BANKSEL EECON1 ; Select Bank of

; EECON1

BCF EECON1, EEPGD ; Point to DATA

; memory

BSF EECON1, WREN ; Enable writes

BCF INTCON, GIE ; Disable INTs.

MOVLW 55h ;

MOVWF EECON2 ; Write 55h

MOVLW AAh ;

MOVWF EECON2 ; Write AAh

BSF EECON1, WR ; Set WR bit to

; begin write

BSF INTCON, GIE ; Enable INTs.

BCF EECON1, WREN ; Disable writes

Required

Sequence

PIC16F818/819

DS39598E-page 28  2004 Microchip Technology Inc.

3.5 Reading Flash Program Memory

To read a program memory location, the user must

write two bytes of the address to the EEADR and

EEADRH registers, set the EEPGD control bit

(EECON1<7>) and then set control bit, RD

(EECON1<0>). 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” ins tructi on to be ig nored. Th e dat a

is available in the very next cycle in the EEDATA and

EEDATH registers; therefore, it can be read as two

bytes in the following instructions. EEDATA and

EEDATH registers will hold this value u ntil anothe r read

or until it is written to by the user (during a write

operation).

EXAMPLE 3-3: FLASH PROGRAM READ

3.6 Erasing Flash Program Memory

The minimum erase block is 32 words. Only through

the use of an external programmer, or through ICSP

control, can larger blocks of program memory be bulk

erase d. Word erase in the Fla sh array is not supporte d.

When initiating an erase sequence from the micro-

controll er itself, a blo ck of 32 words of program memory

is erased. The Most Significant 11 bits of the

EEADRH:EEADR point to the block being erased.

EEADR< 4:0> are ignored.

The EECON1 register commands the erase operation.

The EEPGD bit must be set to point to the Flash

progra m memory. The WREN bit must be set to enable

write op erations. T he FREE bit is s et to select an e rase

operation.

For protec tio n, t he w ri te i nit iate sequ enc e f or EECO N2

must be used.

After the “BSF EECON1, WR” instruction, the processor

requires two cycles to set up the erase operation. The

user mus t place two NOP ins tructions after the WR b it is

set. The processor will halt internal operations for the

typical 2 ms, only during the cycle in which the erase

takes place. 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.

3.6.1 FLASH PROGRAM MEMORY

ERASE SEQUENCE

The sequence of events for erasing a block of internal

program memory location is:

1. Load EEADRH:EEADR with address of row

being erased.

2. Set EEPGD bit to point to program memo ry; set

WREN bit to enable writes and set FREE bit to

enable the erase.

3. Disable int errup ts.

4. Write 55h to EECON2.

5. Write AAh to EECON2.

6. Set the WR bit. This will begin the row erase

cycle.

7. The CPU will stall for duration of the erase.

BANKSEL EEADRH ; Select Bank of EEADRH

MOVF ADDRH, W ;

MOVWF EEADRH ; MS Byte of Program

; Address to read

MOVF ADDRL, W ;

MOVWF EEADR ; LS Byte of Program

; Address to read

BANKSEL EECON1 ; Select Bank of EECON1

BSF EECON1, EEPGD ; Point to PROGRAM

; memory

BSF EECON1, RD ; EE Read

;

NOP ; Any instructions

; here are ignored as

NOP ; program memory is

; read in second cycle

; after BSF EECON1,RD

BANKSEL EEDATA ; Select Bank of EEDATA

MOVF EEDATA, W ; DATAL = EEDATA

MOVWF DATAL ;

MOVF EEDATH, W ; DATAH = EEDATH

MOVWF DATAH ;

 2004 Microchip Technology Inc. DS39598E-page 29

PIC16F818/819

EXAMPLE 3-4: ERASING A FLASH PROGRAM MEMORY ROW

BANKSEL EEADRH ; Select Bank of EEADRH

MOVF ADDRH, W ;

MOVWF EEADRH ; MS Byte of Program Address to Erase

MOVF ADDRL, W ;

MOVWF EEADR ; LS Byte of Program Address to Erase

ERASE_ROW

BANKSEL EECON1 ; Select Bank of EECON1

BSF EECON1, EEPGD ; Point to PROGRAM memory

BSF EECON1, WREN ; Enable Write to memory

BSF EECON1, FREE ; Enable Row Erase operation

;

BCF INTCON, GIE ; Disable interrupts (if using)

MOVLW 55h ;

MOVWF EECON2 ; Write 55h

MOVLW AAh ;

MOVWF EECON2 ; Write AAh

BSF EECON1, WR ; Start Erase (CPU stall)

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, FREE ; Disable Row Erase operation

BCF EECON1, WREN ; Disable writes

BSF INTCON, GIE ; Enable interrupts (if using)

PIC16F818/819

DS39598E-page 30  2004 Microchip Technology Inc.

3.7 Writing to Flash Program Memory

Flash program memory may only be written to if the

desti nati on addr ess i s in a segment of me mory th at is

not write-protected, as defined in bits WRT1:WRT0 of

the device Configuration Word (Register 12-1). Flash

prog ram memor y must b e writte n in four -word bl ocks.

A block consists of four words with sequential

addresses, with a lower boundary defined by an

addr ess, wher e EE ADR< 1:0 > = 00. At the same time,

all bl ock w rit es t o prog ram me mor y are d one as wr ite-

only operations. The program memory must first be

erased. Th e write operation is edge-aligned and cannot

occur across boundaries.

To write to the program memory, the data must first be

loaded into the buffer registers. There are four 14-bit

buffer registers and they are addressed by the low

2 bits of EEADR.

The following sequence of events illustrate how to

perform a w rite to program memory:

• Set the EEPGD and WREN bits in the EECON1

• Clear the FREE bit in EECON1

• Write address to EEADRH:EEADR

• Write data to EEDATH:EEDATA

• Write 55 to EECON2

• Write AA to EECON2

• Set WR bit in EECON 1

The user must follow the same specific sequence to

initiate the write for each word in the program block by

writing each program word in se quence (00, 01, 10,

11).

There are 4 buffer register words and all four locations

MUST be written to with correct data.

After the “BSF EECON1, WR” instruction, if

EEADR ≠xxxxxx11, then a short write will occur.

This short write-only transfers the data to the buffer

one cycle.

After the “BSF EECON1, WR” instruction, if

EEADR = xxxxxx11, then a long write will occur. This

will simultaneously transfer the data from

EEDATH:EEDATA to the buffer reg isters and be gin the

write of all four words. The processor will execute the

next instruction and then ignore the subsequent

inst ruction. The us er should pl ace NOP instr uctions in to

the seco nd wo rds. Th e pro ce ssor w ill th en halt internal

operat io ns for typ ic all y 2 msec in which the write ta ke s

place. This is not a Sleep mode, as the clocks and

peripherals will continue to run. After the write cycle,

the processor will resume operation with the 3rd

instruction after the EECON1 write instruction.

After each l ong write, th e 4 buffe r regist ers will be res et

to 3FFF.

FIGURE 3-1: BLOCK WRITES TO FLASH PROGRAM MEMORY

14 14 14 14

Program Memory

Buffer Register

EEADR<1:0> = 00

Buffer Register

EEADR<1:0> = 01

Buffer Register

EEADR<1:0> = 10

Buffer Register

EEADR<1:0> = 11

EEDATA

EEDATH

75 07 0

First word of block

to be written

to Flash

automatically

after this word

is wri tt e n

transferred

All buffers are

 2004 Microchip Technology Inc. DS39598E-page 31

PIC16F818/819

An example of the complete four-word write sequence

is shown in Example 3-5. The initial address is loaded

into the EEADRH:EEADR register pair; the four words

of da ta a re load ed us ing in direct addres sing, assum ing

that a row erase sequence has already been

performed.

EXAMPLE 3-5: WRITING TO FLASH PROGRAM MEMORY

; This write routine assumes the following:

; 1. The 32 words in the erase block have already been erased.

; 2. A valid starting address (the least significant bits = '00') is loaded into EEADRH:EEADR

; 3. This example is starting at 0x100, this is an application dependent setting.

; 4. The 8 bytes (4 words) of data are loaded, starting at an address in RAM called ARRAY.

; 5. This is an example only, location of data to program is application dependent.

; 6. word_block is located in data memory.

BANKSEL EECON1 ;prepare for WRITE procedure

BSF EECON1, EEPGD ;point to program memory

BSF EECON1, WREN ;allow write cycles

BCF EECON1, FREE ;perform write only

BANKSEL word_block

MOVLW .4

MOVWF word_block ;prepare for 4 words to be written

BANKSEL EEADRH ;Start writing at 0x100

MOVLW 0x01

MOVWF EEADRH ;load HIGH address

MOVLW 0x00

MOVWF EEADR ;load LOW address

BANKSEL ARRAY

MOVLW ARRAY ;initialize FSR to start of data

MOVWF FSR

LOOP

BANKSEL EEDATA

MOVF INDF, W ;indirectly load EEDATA

MOVWF EEDATA

INCF FSR, F ;increment data pointer

MOVF INDF, W ;indirectly load EEDATH

MOVWF EEDATH

INCF FSR, F ;increment data pointer

BANKSEL EECON1

MOVLW 0x55 ;required sequence

MOVWF EECON2

MOVLW 0xAA

MOVWF EECON2

BSF EECON1, WR ;set WR bit to begin write

NOP ;instructions here are ignored as processor

NOP

BANKSEL EEADR

INCF EEADR, f ;load next word address

BANKSEL word_block

DECFSZ word_block, f ;have 4 words been written?

GOTO loop ;NO, continue with writing

BANKSEL EECON1

BCF EECON1, WREN ;YES, 4 words complete, disable writes

BSF INTCON, GIE ;enable interrupts

Required

Sequence

PIC16F818/819

DS39598E-page 32  2004 Microchip Technology Inc.

3.8 Protection Against Spurious Write

There are conditions when the device should not write

to the data EEPROM memory. To protect against

spurious EEPROM writes, various mechanisms have

been b uilt-in. On power-u p, WREN is cleared. Also, th e

Power-up Timer (72 ms duration) prevents an

EEPROM write.

The wri te in iti ate sequenc e an d the WR EN bi t tog ether

help prevent an accidental write during brown-out,

power glitch or software malfunction.

3.9 Operation During Code-Protect

When the dat a EEPROM is code- prote ct ed, the micro-

controll er can read and writ e to th e EEPROM n ormally.

However, all external access to the EEPROM is

disabl ed. External write access to the progra m memory

is also disabled.

When program memory is code-protected, the micro-

controller can read and write to program memory

normally as well as execute instructions. Writes by the

device may be selectively inhibited to regions of

the memory depending on the setting of bits,

WRT1:WRT0, of the Configuration Word (see

Section 12.1 “Configuration Bits” for additional

information). External access to the memory is also

disabled.

TABLE 3-1: REGISTERS/BITS ASSOCIATED WITH DATA EEPROM AND

FLASH PROGRAM MEMORIES

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on

Power-on

Reset

Value on

all othe r

Resets

10Ch EEDATA EEPROM/Flash Data Register Low Byte xxxx xxxx uuuu uuuu

10Dh EEADR EEPROM/Flash Address Register Low Byte xxxx xxxx uuuu uuuu

10Eh EEDATH —— EE PROM /Flash Data Register High Byte --xx xxxx --uu uuuu

10Fh EEADRH — — — — — EEPROM/Flash Address

18Ch EECON1 EEPGD —— FREE WRERR WREN WR RD x--x x000 x--x q000

18Dh EECON2 EEPROM Control Register 2 (not a physical register) ---- ---- ---- ----

0Dh PIR2 — — — EEIF — — — — ---0 ---- ---0 ----

8Dh PIE2 — — —EEIE— — — — ---0 ---- ---0 ----

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’, q = value depends upon condition.

Shaded cells are not used by data EEPROM or Flash program memory.

 2004 Microchip Technology Inc. DS39598E-page 33

PIC16F818/819

4.0 OSCILLATOR

CONFIGURATIONS

4.1 Oscillator Types

The PIC16F818/819 can be operated in eight different

oscillator modes. The user can program three configu-

ration bits (FOSC2:FOSC0) to select one of these eight

modes (modes 5-8 are new PIC16 oscillator

configurations):

1. LP Low-Power Cr ysta l

2. XT Crystal/Resonator

3. HS High-Speed Crystal/Resonator

4. RC External Resistor/Capacitor with

FOSC/4 output on RA6

5. RCIO Extern al Resi stor/Capacitor with

I/O on RA6

6. INTIO1 Intern al Osci ll ator with FOSC/4

output on RA6 and I/O on RA7

7. INTIO2 Internal Oscillator with I/O on RA6

and RA7

8. ECIO External Clock with I/O on RA6

4.2 Crystal Oscillator/Ceramic

Resonators

In XT, LP or HS modes, a crystal or ceramic resonator

is connected to the OSC1/CLKI and OSC2/CLKO pins

to est abl ish osci llatio n (see Fi gure 4-1 and Fi gure 4-2).

The PIC16F818/819 oscillator design requires the use

of a parallel cut crystal. Use of a series cut crystal may

give a frequency out of the crystal manufacturer’s

specifications.

FIGURE 4-1: CRYSTAL OPERATION

(HS, XT OR LP OSC

CONFIGURATION)

T ABLE 4-1: CAP ACITOR SELECTION FOR

CRYSTAL OSCILLATOR (FOR

DESIGN GUIDANCE ONLY)

Note 1: See Table 4-1 for typical values of C1 and C2.

2: A series resi stor (RS) may be required for AT

strip cut crystals.

3: RF varies with the crystal chosen (typically

between 2 MΩ to 1 0 MΩ).

C1(1)

C2(1)

XTAL

OSC2

RS(2)

OSC1

RF(3) Sleep

To Internal

Logic

PIC16F818/819

Osc Type Crystal

Freq

Typica l Cap acitor V alues

Tested:

C1 C2

LP 32 kHz 33 pF 33 pF

200 kHz 15 pF 15 pF

XT 200 kHz 56 pF 56 pF

1 MHz 15 pF 15 pF

4 MHz 15 pF 15 pF

HS 4 MHz 15 pF 15 pF

8 MHz 15 pF 15 pF

20 MHz 15 pF 15 pF

Capacitor values are for design guidance only.

These capacito rs were tested with th e crystals listed

below for basic start-up and operation. These values

were not optimized.

Dif ferent capa citor values m ay be required to prod uce

acceptable oscillator operation. The user should test

the performance of the oscillator over the expected

VDD and temperature range for the application.

See the notes following this table for additional

information.

Note 1: Higher capacitance increases the stability

of the oscillator but also increases the

sta rt-up time.

2: Since each crystal has its own character-

istic s, th e use r shoul d cons ult th e crys tal

manufacturer for appropriate values of

external components.

3: RS may be r equ ired in HS mode , as we ll

as XT mode, to av oid ove rdriving cry st als

with low driv e level specification.

4: Always veri fy os ci lla tor performanc e ov er

the VDD and temperature range that is

expected for the application.

PIC16F818/819

DS39598E-page 34  2004 Microchip Technology Inc.

FIGURE 4-2: CERAMIC RESONATOR

OPERATION (HS OR XT

OSC CONFIGURATION)

TABLE 4-2: CERAMIC RESONATORS (FOR

DESIGN GUIDANC E O NLY)

4.3 External Clock Input

The ECIO Oscillator mode requires an external clock

source to be connected to the OSC1 pin. There is no

oscill ator s ta rt-up ti me required afte r a P ower-o n Res et

or after an exit from Sleep mode.

In the ECIO Oscillator mode, the OSC2 pin becomes

an additional general purpose I/O pin. The I/O pin

becomes bit 6 of PORTA (RA6). Figure 4-3 shows the

pin connections for the ECIO Oscillator mode.

FIGURE 4-3: EXTERNAL CLOCK INPUT

OPERATION

(ECIO CONFIGURATION)

Typical Capacitor Values Used:

Mode Freq OSC1 OSC2

XT 455 kHz

2.0 MHz

4.0 MHz

56 pF

47 pF

33 pF

56 pF

47 pF

33 pF

HS 8.0 MHz

16.0 MHz 27 pF

22 pF 27 pF

22 pF

Capacitor values are for design guidance only.

These capacitors were tested with the resonators

listed below for basic start-up and operation. These

values were not optimized.

Dif ferent cap acitor values ma y be required to prod uce

acceptable oscillator operation. The user should test

the performance of the oscillator over the expected

VDD and temperature range for the application.

See the notes following this table for additional

information.

Note: When using resonators with frequencies

above 3.5 MHz, t he use of HS mode rather

than XT mode is recommend ed. HS mode

may be used at any VDD for which the

controller is rated. If HS is selected, it is

possible that the gain of the oscillator will

overdrive the resonator. Therefore, a

series resistor should be placed between

the OSC2 pin and the resonator. As a

good starting point, the recommended

value of RS is 330 Ω.

Note 1: See Table 4-2 for typical values of C1 and C2.

2: A series resistor (RS) may be required.

3: RF varies with the resonator chosen (ty pically

between 2 MΩ to 10 MΩ).

C1(1)

C2(1)

RES

OSC2

RS(2)

OSC1

RF(3) Sleep

To Internal

Logic

PIC16F818/819

OSC1/CLKI

I/O (OSC2)

RA6

Clock from

Ext. System PIC16F818/819

 2004 Microchip Technology Inc. DS39598E-page 35

PIC16F818/819

4.4 RC Oscillator

For timing insensitive applications, the “RC” and

“RCIO” device options offer additional cost savings.

The RC oscillator frequency is a function of the supply

voltage, the resistor (REXT) and capacitor (CEXT)

values and the operating temperature. In addition to

this, the oscillator frequency will vary from unit to unit

due to normal manufacturing variation. Furthermore,

the dif ference in lead frame capacitance between pack-

age types will also affect the oscillation frequency,

especi all y for lo w CEXT values. The user also nee ds to

take into account variation due to tolerance of external

R and C components used. Figure 4-4 shows how the

R/C combination is connected.

In the RC Oscillator mode, the oscillator frequency

divided by 4 is available on the OSC2 pin. This signal may

be used for test purposes or to synchronize other logic.

FIGURE 4-4: RC OSCILLATOR MODE

The RCIO Oscillator mode (Figure 4-5) functions like

the RC mode except that the OSC2 pin becomes an

additional general purpose I/O pin. The I/O pin

becomes bit 6 of PORTA (RA6).

FIGURE 4-5: RCIO OSCILLATOR MODE

4.5 Internal Oscil lator Block

The PIC16F818/819 devices include an internal

oscillator block which generates two different clock

signals; either can be used as the system’s clock

source. This can eliminate the need for external

oscillator circuits on the OSC1 an d/or OSC2 pins.

The main output (INTOSC) is an 8 MHz clock source

which can be used to directly drive the system clock. It

also driv es the INT OSC postscal er which can prov ide a

range of clock frequencies from 125 kHz to 4 MHz.

The other clock source is the internal RC oscillator

(INTRC) which provides a 31.25 kHz (32 µs nominal

period) output. The INTRC oscillator is enabled by

selecting the INTRC as the system clock source or

when any of the following are enabled:

• Power-up Timer

• Watchdog Timer

These features are discussed in greater detail in

Section 12.0 “Special Features of the CPU”.

The clock source frequency (INTOSC direct, INTRC

direct or INTOSC postscaler) is selected by configurin g

the IRCF bits of the OSCCON register (Register 4-2).

4.5.1 INTRC MODES

Using the internal oscillator as the clock source can

elimin ate the ne ed for up to two extern al oscil lator pins,

which can then be used for digital I/O. Two distinct

configurations are available:

• In INTIO1 mode, the OSC 2 pin outputs FOSC/4

while OSC1 functions as RA7 for digital input and

output.

• In INTIO2 mode, OSC1 functions as RA7 and

OSC2 functions as RA6, both for digital input and

output.

OSC2/CLKO

CEXT

REXT

PIC16F818/819

OSC1

FOSC/4

Internal

Clock

VDD

VSS

Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ

CEXT > 20 pF

CEXT

REXT

PIC16F818/819

OSC1 Internal

Clock

VDD

VSS

Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ

CEXT > 20 pF

I/O (OSC2)

RA6

Note: Throughout this dat a sheet, when referring

specifically to a generic clock source, the

term “INTRC” may als o be used to refer to

the clock modes using the internal

oscillator block. This is regardless of

whether the actual frequency used is

INTOSC (8 MHz), the INTOSC postscaler

or INTRC (31.25 kHz).

PIC16F818/819

DS39598E-page 36  2004 Microchip Technology Inc.

4.5.2 OSCTUNE REGISTER

The internal oscillator’s output has been calibrated at the

factory but can be adjusted in the application. This is

done by writing to the OSCTUNE register (Register 4-1).

The tuning sensitivity is constant throughout the tuning

range. The OSCTUNE register has a tuning range of

±12.5%.

When the OSCTUNE register is modified, the INTOSC

and INTRC frequencies will begin s hifting to the new fre-

quency. The INTRC clock will reach the new frequency

within 8 clock cycles (approximately 8 * 32 µs = 256 µs);

the INTOSC clock will st abilize within 1 ms. Code execu-

tion continues du ring this shift. There is no indication that

the shift has occurred. Operation of fea tures that depend

on the 31.25 kHz INTRC clock source frequency, such

as the WDT, Fail-Safe Clock Monitor and peripherals,

will also be af fec ted by the cha nge in frequency.

U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

—— TUN5 TUN4 TUN3 TUN2 TUN1 TUN0

bit 7 bit 0

bit 7-6 Unimplemented: Read as ‘0’

bit 5-0 TUN<5:0>: Frequency Tuning bits

011111 = Maximum frequency

011110 =

•

000001 =

000000 = Center frequency. Oscillator module is running at the calibrated frequency.

111111 =

•

100000 = Minimum frequency

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 37

PIC16F818/819

4.5.3 OSCILLATOR CONTROL REGISTER

The OSCCON register (Register 4-2) controls several

aspects of the system clock’s operation.

The Internal Oscillator Select bit s, IRCF2:IRCF0, select

the freque ncy o utput o f the int erna l oscill ator bl ock th at

is use d to driv e th e sys tem cl ock. The c hoi ces a re t he

INTRC source (31.25 kHz), the INTOSC source

(8 MHz) or one of the six frequencies derived from the

INTOSC postscaler (125 kHz to 4 MHz). Changing the

configuration of these bits has an immediate change on

the multiplexor’s frequency output.

4.5.4 MODIFYI NG THE IRCF BITS

The IRCF bits can be modified at any time regardless of

which clock source is currently being used as the

system clock. The internal oscillator allows users to

change the frequency during run time. This is achieved

by modifying the IRCF bits in the OSCCON register.

The sequen ce of events th at occur after the IRCF bits

are modified is dependent upon the initial value of the

IRCF bits before they are modified. If the INTRC

(31.25 kHz, IRCF<2:0> = 000) is running and the IRCF

bits are modified to any other va lue than ‘000’, a 4 ms

(approx. ) clock swit ch delay is turned o n. Code e xecu-

tion continues at a higher than expected frequency

while the new frequency stabilizes. Time sensitive code

should wait for the IOFS bit in the OSCCON register to

become set before continuing. This bit can be

monitored to ensure that the frequency is stable before

using the system clock in time critical applications.

If th e IRCF b its a re modif ied wh ile the internal oscilla tor

is running at any other frequency than INTRC

(31.25 kHz, IRCF<2:0> ≠ 000), there is no need for a

4 ms (approx.) clock switch delay. The new INTOSC

frequency will be stable immediately after the eight

falling edges. The IOFS bit will remain set after clock

switching occurs.

4.5.5 CLOCK T RANSITION SEQUENCE

WHEN THE IRCF BITS ARE

MODIFIED

Following are three different sequences for switching

the internal RC oscillator frequency.

• Clock before switch: 31.25 kHz (IRCF<2:0> = 000)

1. IRCF bits are modified to an INTOSC/INTOSC

postscaler frequency.

2. The clock switching circuitry waits for a falling

edge of the current clock, at which point CLKO

is held low.

3. Th e clock switching c ircuitry th en waits for eight

falling edges of requested clock, after which it

switches CLKO to this new clock source.

4. Th e IOFS bit is clear to indica te that the cloc k is

unstable and a 4 ms (approx.) delay is started.

Time dependent code should wait for IOFS to

become set.

5. Switchover is complete.

• Clock before switch: One of INTOSC/INTOSC

postscaler (IRCF<2:0> ≠ 000)

1. IRCF bits are modified to INTRC

(IRCF<2:0> = 000).

2. The clock switching circuitry waits for a falling

edge of the current clock, at which point CLKO

is held low.

3. Th e clock switching c ircuitry th en waits for eight

falling edges of requested clock, after which it

switches CLKO to this new clock source.

4. Oscillator switchover is complete.

• Clock before switch: One of INTOSC/INTOSC

postscaler (IRCF<2:0> ≠ 000)

1. IRCF bits are modified to a different INTOSC/

INTOSC postscaler frequency.

2. The clock switching circuitry waits for a falling

edge of the current clock, at which point CLKO

is held low.

3. The clock switching circuitry then waits for eight

falling edges of requested clock, after which it

switches CLKO to this new clock source.

4. The IOFS bit is set.

5. Oscillator switchover is complete.

Note: Caution must be t aken when mod ifying the

IRCF bits using BCF or BSF instructions. It

is possible to modify the IRCF bits to a

frequency that may be out of the VDD spec-

ification range; for example, VDD = 2.0V

and IRCF = 111 (8 MHz).

PIC16F818/819

DS39598E-page 38  2004 Microchip Technology Inc.

FIGURE 4-6: PIC16F818/8 19 CLOC K DIAGRAM

PIC18F818/819 CONFIG (FOSC2:FOSC0)

OSC1

OSC2

Sleep LP, XT, HS, RC, EC

CPU

Peripherals

Postscaler

MUX

8 MHz

4 MHz

2 MHz

1 MHz

500 kHz

125 kHz

250 kHz

OSCCON<6:4>

111

110

101

100

011

010

001

000

31.25 kHz

Source

Internal

Oscillator

Block

WDT

31.25 kHz

8 MHz

Internal Oscillator

(INTRC)

(INTOSC)

U-0 R/W-0 R/W-0 R/W-0 U-0 R-0 U-0 U-0

— IRCF2 IRCF1 IRCF0 —IOFS— —

bit 7 bit 0

bit 7 Unimplemented: Read as ‘0’

bit 6-4 IRCF2:IRCF0: Internal Oscillator Frequency Select bits

111 = 8 MHz (8 MHz source drives clock directly)

110 = 4 MHz

101 = 2 MHz

100 = 1 MHz

011 = 500 kHz

010 = 250 kHz

001 = 125 kHz

000 = 31.25 kHz (INTRC source drives clock directly)

bit 3 Unimplemented: Read as ‘0’

bit 2 IOFS: INTOSC Frequency Stable bit

1 = Frequency is stable

0 = Frequency is not stable

bit 1-0 Unimplemented: Read as ‘0’

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 39

PIC16F818/819

5.0 I/O P ORTS

Some pins for these I/O ports are multiplexed with an

alternate function for the peripheral features on the

device. In general, when a peripheral is enabled, that

pin may not be used as a general purpose I/O pin.

Addit ion al inf orm atio n o n I/O ports may be found i n th e

“PICmicro® Mid-Range MCU Family Reference

Manual” (DS33023).

5.1 PORTA and the TRISA Register

PORTA is an 8-bit wide, bidirectional port. The corre-

sponding data direction register is TRISA. Setting a

TRISA bit (= 1) will make the corresponding PORTA

pin an input (i.e., put the corresponding output driver in

a high-impedance mode). Clearing a TRISA bit (= 0)

will mak e the correspond ing PORTA pin an outp ut (i.e.,

put the contents of the output latch on the selected pin).

Reading the PORTA register reads the status of the

pins, where as wri tin g to i t will write to th e po rt lat ch. 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 l atch.

Pin RA4 is multiplexed with the Timer0 module clock

input an d with an analog input to become the RA4/ AN4/

T0CKI pin. The RA4/AN4/T0CKI pin is a Schmitt

Trigger input and full CMOS output driver.

Pin RA5 is multiplexed with the Master Clear module

input. The RA5/MCLR/VPP pin is a Schmitt Trigger input.

Pin RA6 is mul tiplexed with th e oscillator module input

and external oscillator output. Pin RA7 is multiplexed

with the oscillator module input and external oscillator

input. Pin RA6/OSC2/CLKO and pin RA7/OSC1/CLKI

are Schmitt Trigger inputs and full CMOS output drivers.

Pins RA<1:0> are multiplexed with analog inputs. Pins

RA<3:2> are multiplexed with analog inputs and VREF

inputs. Pins RA<3:0> have TTL inputs and full CMOS

output drivers.

EXAMPLE 5- 1: INITIALIZI NG PORTA

TABLE 5-1: PORTA FUNCTIONS

TABLE 5-2: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA

Note: On a Power-on Reset, the pins

PORTA<4:0> are configured as analog

inputs and read as ‘0’.

BANKSEL PORTA ; select bank of PORTA

CLRF PORTA ; Initialize PORTA by

; clearing output

; data latches

BANKSEL ADCON1 ; Select Bank of ADCON1

MOVLW 0x06 ; Configure all pins

MOVWF ADCON1 ; as digital inputs

MOVLW 0xFF ; Value used to

; initialize data

; direction

MOVWF TRISA ; Set RA<7:0> as inputs

Name Bit# Buffer Function

RA0/AN0 bit 0 TTL Input/output or analog input.

RA1/AN1 bit 1 TTL Input/output or analog input.

RA2/AN2/VREF- bit 2 TTL Input/output, analog input or VREF-.

RA3/AN3/VREF+ bit 3 TTL Input/output, analog input or VREF+.

RA4/AN4/T0CKI bit 4 ST Input/output, analog input or external clock input for Timer0.

RA5/MCLR/VPP bit 5 ST Input, Master Clear (Reset) or programming voltage input.

RA6/OSC2/CLKO bit 6 ST Input/output, connects to crystal or resonator, oscillator output or 1/4 the

frequency of OSC1 and denotes the instruction cycle in RC mode.

RA7/OSC1/CLKI bit 7 ST/CMOS(1) Input/output, connects to crystal or resonator or oscillator input.

Legend: TTL = TTL input, ST = Schmitt Trigger input

Note 1: This buffer is a Sch mitt Trigger input when configu red in RC Os cill ator mode and a CMOS inp ut otherwis e.

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

05h PORTA RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0 xxx0 0000 uuu0 0000

85h TRISA TRISA7 TRISA6 TRISA5(1) PORTA Data Direction Register 1111 1111 1111 1111

9Fh ADCON1 ADFM ADCS2 —— PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 00-- 0000

Legend: x = unknown, u = unchanged, - = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.

Note 1: Pin 5 is an input only; the state of the TRISA5 bit has no effect and will always read ‘1’.

PIC16F818/819

DS39598E-page 40  2004 Microchip Technology Inc.

FIGURE 5-1: BLOCK DIAGRAM OF

RA0/AN0:RA1/AN1 PINS

FIGURE 5-2: BLOCK DIAGRAM OF

RA3/AN3/VREF+ PIN

FIGURE 5-3: BLOCK DIAGRAM OF

RA2/AN2/VREF- PIN

FIGURE 5-4: BLOCK DIAGRAM OF

RA4/AN4/T0CKI PIN

Data

Bus QD

CK P

PORTA

TRISA

Data Latch

TRIS Latch

RD TRISA

RD PORTA

Analog VSS

VDD

I/O pin

Input Mode

TTL

Input Buffer

VDD

To A/D Module Channel Input

VSS

Data

Bus QD

CK P

PORTA

TRISA

Data Latch

TRIS Latch

RD TRISA

RD PORTA

Analog VSS

VDD

I/O pin

Input Mode

VDD

To A/D Module Channel Input

To A/D Module VREF+ Input

VSS

TTL

Input Buffer

Data

Bus QD

CK P

PORTA

TRISA

Data Latch

TRIS Latch

RD TRISA

RD PORTA

Analog VSS

VDD

I/O pin

Input Mode

VDD

To A/D Module Channel Input

To A/D Module VREF- Input

VSS

TTL

Input Buffer

Data

Bus QD

CK P

PORTA

TRISA

Data Latch

TRIS Latch

RD TRISA

RD PORTA

Analog VSS

VDD

I/O pin

Input Mode

VDD

To A/D Module Channel Input

TMR0 Clock Input

VSS

Schmitt Trigger

Input Buffer

 2004 Microchip Technology Inc. DS39598E-page 41

PIC16F818/819

FIGURE 5-5: BLOCK DIAGRAM OF RA5/MCLR/VPP PIN

FIGURE 5-6: BLOCK DIAGRAM OF RA6/OSC2/CLKO PIN

MCLR Filter

RA5/MCLR/VPP

RD Port

MCLR Circuit

MCLRE

Data

Bus

RD TRIS

Schmitt Trigger

Buffer

VSS

VSS Schmitt Trigger

Input Buffer

Data

Bus QD

PORTA

TRISA

Data Latch

TRIS Latch

RD TRISA

RD PORTA

VSS

VDD

RA6/OSC2/CLKO

Oscillator

Circuit

From OSC1

(FOSC = 1x0,011)

VSS

VDD

CLKO (FOSC/4)

VDD

Note 1: I/O pins have protection diodes to VDD and VSS.

2: CLKO signal is 1/4 of the FOSC frequency.

(FOSC = 1x1)VSS

Schmitt Tri gger

Input Buffer

(FOSC = 1x0,011)

PIC16F818/819

DS39598E-page 42  2004 Microchip Technology Inc.

FIGURE 5-7: BLOCK DIAGRAM OF RA7/OSC1/CLKI PIN

Data

Bus QD

PORTA

TRISA

Data Latch

TRIS Latch

RD TRISA

RD PORTA

Oscillator

Circuit

RA7/OSC1/CLKI

VSS

VDD

FOSC = 10x

VDD

Note 1: I/O pins have protection diodes to VDD and VSS.

(FOSC = 011)

FOSC = 10x

From OSC2

VSS

Schmitt Tri gger

Input Buffer

 2004 Microchip Technology Inc. DS39598E-page 43

PIC16F818/819

5.2 PORTB and the TRISB Register

PORTB is an 8-bit wide, bidirectional port. The corre-

sponding data direction register is TRISB. Setting a

TRISB bit (= 1) will make the corresponding PORTB

pin an input (i.e., put the corresponding output driver in

a high-impedance mode). Clearing a TRISB bit (= 0)

will make th e corresp onding POR TB pi n an out put (i.e .,

put the contents of the output latch on the selected pin).

Each of th e POR TB pins has a we ak inte rnal pul l-up. A

single control bit can turn on all the pull-ups. This is

performed by clearing bit RBPU (OPTION_REG<7>).

The weak pull-up is automatically turned off when the

port pin is configured as an output. The pull-ups are

disabled on a Power-on Reset.

Four of POR TB’s pi ns, RB7:RB4, hav e an interrupt-o n-

change feature. Only pins configured as inputs can

cause this interrupt to occur (i.e., any RB7:RB4 pin

configured as an output is excluded from the interrupt-

on-change comparison). The input pins (of RB7:RB4)

are compared with the old value latched on the last

read of PORTB. The “mismatch” outputs of RB7:RB4

are ORed together to generate the RB Port Change

Interrupt with Flag bit, RBIF (INTCON<0>).

This interrupt can wake the device from Sleep. The

user, in the Interrupt Service Routine, can clear the

inter rupt in the fol lowi ng man ne r :

a) Any read or write of PORTB. This will end the

mismatch condition.

b) Clear flag bit RBIF.

A mism at c h c ond it i on wi ll co nti n ue to s et f lag bi t RB IF.

Reading PORTB will end the mismatch condition and

allow flag bit RBIF to be cleared.

The interrupt-on-change feature is recommended for

wake-up on key depression operation and operations

where PORTB is only used for the interrupt-on-change

feature. Polling of PORTB is not recommended while

using the interrupt-on-change feature.

RB0/INT is an external interrupt input pin and is

configured using the INTEDG bit (OPTION_REG<6>).

PORTB i s multiplexe d with several pe ripheral function s

(see Table 5-3). PORTB pins have Schmitt Trigger

input buffers.

When enabling peripheral functions, care should be

taken in defining TRIS bits for each PORTB pin. Some

peripherals override the TRIS bit to make a pin an out-

put, while other peripherals override the TRIS bit to

make a pin an input. Since the TRIS bit override is in

effect while the peripheral is enabled, read-modify-

write instructions (BSF, BCF, XORWF) with TRISB as

the destination should be avoided. The user should

refer to the corresponding peripheral section for the

correct TRIS bit settings.

PIC16F818/819

DS39598E-page 44  2004 Microchip Technology Inc.

TABLE 5-3: PORTB FUNCTIONS

TABLE 5-4: SUMMARY OF REGISTERS ASSOCIATED WITH PORTB

Name Bit# Buffer Function

RB0/INT bit 0 TTL/ST(1) Input/output pin or external interrupt input.

Internal software programmable weak pull-up.

RB1/SDI/SDA bit 1 TTL/ST(5) Input/output pin, SPI™ data input pin or I2C™ data I/O pin.

Internal software programmable weak pull-up.

RB2/SDO/CCP1 bit 2 TTL/ST(4) Input/output pin, SPI data output pin or

Capture input/Compare output/PWM output pin.

Internal software programmable weak pull-up.

RB3/CCP1/PGM(3) bit 3 TTL/ST(2) Input/output pin, Capture input/Compare output/PWM output pin

or programming in LVP mode. Internal software programmable

weak pull-up.

RB4/SCK/SCL bit 4 TTL/ST(5) Input/output pin or SPI and I2C clock pin (with interrupt-on-change).

Internal software programmable weak pull-up.

RB5/SS bit 5 TTL Input/output pin or SPI slave select pin (with interrupt-on-change).

Internal software programmable weak pull-up.

RB6/T1OSO/T1CKI/

PGC bit 6 TTL/ST(2) Input/output pin, Timer1 oscillator output pin, Timer1 clock input pin or

serial prog ram ming cl ock (wi th inte rrupt -on-c ha nge ).

Internal software programmable weak pull-up.

RB7/T1OSI/PGD bit 7 TTL/ST(2) Input/output pin, Timer1 oscillator input pin or serial programming data

(with interrupt-on-change).

Internal software programmable weak pull-up.

Legend: TTL = TTL input, ST = Schmitt Trigger input

Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.

2: This buffer is a Schmitt Trigger input when used in Serial Progr amming mode.

3: Low-Voltage ICSP™ Programming (LVP) is enabled by default which disables the RB3 I/O function. LVP

must be disabled to enable RB3 as an I/O pin and allow maximum compatibility to the other 18-pin

mid-range dev ic es .

4: This buffer is a Schmitt Trigger input when configured for CCP or SSP mode.

5: This buffer is a Schmitt Trigger input when configured for SPI or I2C mode.

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

06h, 106h PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx uuuu uuuu

86h, 186h TRISB PORTB Data Direction Register 1111 1111 1111 1111

81h, 181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.

 2004 Microchip Technology Inc. DS39598E-page 45

PIC16F818/819

FIGURE 5-8: BLOCK DIAGRAM OF RB0 PIN

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

Data Latch

RBPU(2)

VDD

Data Bus

RD TRISB

RD PORTB

Weak

Pull-up

RD PORTB

I/O pin(1)

TTL

Input

Buffer

TRIS Latch

To IN T0 or CCP

PORTB

TRISB

PIC16F818/819

DS39598E-page 46  2004 Microchip Technology Inc.

FIGURE 5-9: BLOCK DIAGRAM OF RB1 PIN

Data Latch

RBPU(2)

VDD

Data Bus

RD TRISB

RD PORTB

Weak

Pull-up

RD PORTB

SDA(3)

I/O pin(1)

TTL

Input

Buffer

Schmitt Tr igger

Buffer

TRIS Latch

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

3: The SDA Schmitt Trigger conforms to the I2C specification.

SDA Output

VSS

VDD

SDA Drive

Port/SSPEN Sele ct

I2C™ Mode

SDI

PORTB

TRISB

 2004 Microchip Technology Inc. DS39598E-page 47

PIC16F818/819

FIGURE 5-10: BLOCK DIAGRAM OF RB2 PIN

Data Latch

RBPU(2)

VDD

Data Bus

RD TRISB

RD PORTB

Weak

Pull-up

RD PORTB

I/O pin(1)

TTL

Input

Buffer

TRIS Latch

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

CCPMX

CCP

SDO

Module Select

PORTB

TRISB

PIC16F818/819

DS39598E-page 48  2004 Microchip Technology Inc.

FIGURE 5-11: BLOCK DIAGRAM OF RB3 PIN

Data Latch

RBPU(2)

VDD

Data Bus

RD TRISB

RD PORTB

Weak

Pull-up

RD PORTB

I/O pin(1)

TTL

Input

Buffer

TRIS Latch

PORTB

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

CCP

To PGM or CCP

CCP1<M3:M0> = 1000, 1001, 11xx and CCPMX = 0

CCP1<M3: M0> = 0100, 0101, 0110, 0111 and CCPMX = 0

or LVP = 1

TRISB

 2004 Microchip Technology Inc. DS39598E-page 49

PIC16F818/819

FIGURE 5-12: BLOCK DIAGRAM OF RB4 PIN

Data Latch

From other

RBPU(2)

VDD

I/O pin(1)

Data Bus

Set RBIF

TRIS Latch

RD TRISB

RD PORTB

RB7:RB4 pins

Weak

Pull-up

RD PORTB

Latch

TTL

Input

Buffer

PORTB

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

3: The SCL Schmitt Trigger conforms to the I2C™ specification.

SCK

SCK/SCL 1

Port/SSPEN

SCL(3)

VSS

VDD

SCL Drive

TRISB

PIC16F818/819

DS39598E-page 50  2004 Microchip Technology Inc.

FIGURE 5-13: BLOCK DIAGRAM OF RB5 PIN

Data Latch

From other

RBPU(2)

VDD

I/O pin(1)

Data Bus

Set RBIF

TRIS Latch

RD TRISB

RD PORTB

RB7:RB4 pins

Weak

Pull-up

RD PORTB

Latch

PORTB

Port/SSPEN

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

TRISB

TTL

Input

Buffer

 2004 Microchip Technology Inc. DS39598E-page 51

PIC16F818/819

FIGURE 5-14: BLOCK DIAGRAM OF RB6 PIN

Data Latch

From other

RBPU(2)

VDD

I/O pin(1)

Data Bus

Set RBIF

TRIS Latch

RD TRISB

RD PORTB

RB7:RB4 pins

Weak

Pull-up

RD PORTB

Latch

PORTB

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

T1CKI/PGC

T1OSCEN/ICD/

From T1OSO Output

TTL

Inp ut Bu ffe r

T1OSCEN

TRISB

Program Mode

PIC16F818/819

DS39598E-page 52  2004 Microchip Technology Inc.

FIGURE 5-15: BLOCK DIAGRAM OF RB7 PIN

Data Latch

From other

RBPU(2)

VDD

I/O pin(1)

Data Bus

T1OSCEN

Set RBIF

TRIS Latch

RD TRISB

RD PORTB

RB7:RB4 pins

Weak

Pull-up

RD PORTB

Latch

PORTB

Note 1: I/O pins have diode protection to VDD and VSS.

2: To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit.

PGD

PGD 1

Port/Program Mode/ICD

Analog

TTL

Input Buffer

Input Mode

To T1OSI Input

PGD DRVEN

T1OSCEN

TRISB

 2004 Microchip Technology Inc. DS39598E-page 53

PIC16F818/819

6.0 TIMER0 MODULE

The Timer0 module timer/counter has the following

features:

• 8-bit timer/counter

• Readable and writable

• 8-bit software programmable prescaler

• Internal or external clock select

• Interrupt-on-overflow from FFh to 00h

• Edge select for external clock

Additional information on the Timer0 module is

available in the “PICmicro® Mid-Range MCU Family

Reference Manual” (DS33023).

Figure 6-1 is a bloc k diagram o f the T imer0 mod ule and

the prescaler shared with the WDT.

6.1 Timer0 Operation

Timer0 operation is controlled through the

OPTION_REG register (see Register 2-2). Timer mode

is selected by clearing bit T0CS (OPTION_REG<5>).

In T imer m ode, the T ime r0 module w ill incr ement ever y

instruc tion cy cle (with out pr escal er). If the TMR0 regis-

ter is w ritten , the i ncrem ent is inhi bited f or the follow ing

two instruction cycles. The user can work around this

by writing an adjusted value to the TMR0 register.

Counter mode is selected by setting bit T0CS

(OPTION_REG<5>). In Counter mode, Timer0 will

increment either on every rising or falling edge of pin

RA4/AN4/T0CKI. The incrementing edg e is determined

by the Timer0 Source Edge Select bit, T0SE

(OPTION_REG<4>). Clearing bit T0SE selects the

rising edg e. Restrict ions on the exter nal clock input are

discus sed in detail in Section 6.3 “Using T i mer0 w ith

an External Clock”.

The prescaler is mutually exclusively shared between

the Timer0 module and the Watchdog Timer. The

prescaler is not readable or writable. Section 6.4

“Prescaler” details the operation of the prescaler.

6.2 Timer0 Interrupt

The TMR0 interrupt is generated when the TMR0

bit, TMR0IF (INTCON<2>). The interrupt can be

masked by clearing bit, TMR0IE (INTCON<5>). Bit

TMR0IF must be cleared in software by the Timer0

module Interrupt Service Routine before re-enabling

this interrupt. The TMR0 interrupt cannot awaken the

processor from Sleep since the timer is shut-off during

Sleep.

FIGURE 6-1: BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER

RA4/AN4/T0CKI

T0SE

CLKO (= FOSC/4)

Sync

Cycles TMR0 reg

8-bit Prescaler

8-to-1 MUX

MUX

31.25 kHz

WDT Timer

PSA

WDT

Time-out

PS2:PS0

Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION_REG<5:0>).

PSA

WDT Enable bit

Data Bus

Set Flag bit TMR0IF

on Overflow

PSA

T0CS

PRESCALER

PIC16F818/819

DS39598E-page 54  2004 Microchip Technology Inc.

6.3 Using Timer0 with an

External Clock

When no pr escal er is used, t he ex tern al clo ck inp ut is

the same as the pre sc al er outp ut. Th e sy nch ron iz atio n

of T0CKI with the internal phase clocks is accom-

plishe d by sampling the prescale r output on the Q2 and

Q4 cycles of the internal phase clocks. Therefore, it is

necessary for T0CKI to be high for at least 2 TOSC (and

a small RC delay of 20 ns) and low for at least 2 TOSC

(and a small RC delay of 20 ns). Refer to the electrical

specification of the desired device.

6.4 Prescaler

There is o nly one pr esc al er av ai lable wh ic h is m utu ally

exclus ively shar ed between th e T imer0 mod ule and the

Watchdog Timer. A prescaler assignment for the

T i mer0 m odule m eans that t here i s no presc aler fo r the

Watchdog Timer and vice versa. This prescaler is not

readable or writable (see Figure 6-1).

The PSA and PS2:PS0 bits (OPTION_REG<3:0>)

determine the prescaler assignme nt and prescale ratio.

When assigned to the Timer0 module, all instructions

writing to the TMR0 register (e.g., CLRF 1, MOVWF 1,

BSF 1, x....etc.) will clear the prescaler. When

assigned to WDT, a CLRWDT instruction will clear the

prescaler along with the Watchdog Timer. The

prescaler is not readable or writable.

Note: Writing to TMR0 when the prescaler is

assign ed to Timer0 will cle ar the pre scaler

count but will not change the prescaler

assignment.

R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0

bit 7 bit 0

bit 7 RBPU: PORTB Pull-up Enable bit

1 = PORTB pull-ups are disabled

0 = PORTB pull-ups are enabled by individual port latch values

bit 6 INTEDG: Interrupt Edge Select bit

1 = Interrupt on rising edge of RB0/INT pin

0 = Interrupt on falling edge of RB0/INT pin

bit 5 T0CS: TMR0 Clock Source Select bit

1 = Transition on T0CKI pin

0 = Internal instruction cycle clock (CLKO)

bit 4 T0SE: TMR0 Source Edge Select bit

1 = Increment on high-to-low transition on T0CKI pin

0 = Increment on low-to-high transition on T0CKI pin

bit 3 PSA: Prescaler Assignment bit

1 = Prescaler is assigned to the WDT

0 = Prescaler is assigned to the Timer0 module

bit 2-0 PS2:PS0: Prescaler Rate Select bits

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

Note: To avoid an unintended device Reset, the instruction sequence shown in the

“PICmicro® Mid-Range MCU Family Reference Manual” (DS33023) must be

executed when changing the prescaler assignment from Timer0 to the WDT. This

sequence must be followed even if the WDT is disabled.

000

001

010

011

100

101

110

111

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

1 : 256

1 : 1

1 : 2

1 : 4

1 : 8

1 : 16

1 : 32

1 : 64

1 : 128

Bit Value TMR0 Rate WDT Rate

 2004 Microchip Technology Inc. DS39598E-page 55

PIC16F818/819

EXAMPLE 6-1: CHANGING THE PRESCALER ASSIGNMENT FROM TIMER0 TO WDT

EXAMPLE 6-2: CHANGING THE PRESCALER ASSIGNMENT FROM WDT TO TIMER0

TABLE 6-1: REGISTERS ASSOCIATED WITH TIMER0

BANKSEL OPTION_REG ; Select Bank of OPTION_REG

MOVLW b'xx0x0xxx' ; Select clock source and prescale value of

MOVWF OPTION_REG ; other than 1:1

BANKSEL TMR0 ; Select Bank of TMR0

CLRF TMR0 ; Clear TMR0 and prescaler

BANKSEL OPTION_REG ; Select Bank of OPTION_REG

MOVLW b'xxxx1xxx' ; Select WDT, do not change prescale value

MOVWF OPTION_REG

CLRWDT ; Clears WDT and prescaler

MOVLW b'xxxx1xxx' ; Select new prescale value and WDT

MOVWF OPTION_REG

CLRWDT ; Clear WDT and prescaler

BANKSEL OPTION_REG ; Select Bank of OPTION_REG

MOVLW b'xxxx0xxx' ; Select TMR0, new prescale

MOVWF OPTION_REG ; value and clock source

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Va lue on

POR, BOR

Value on

all othe r

Resets

01h,101h TM R0 Timer0 Module Register xxxx xxxx uuuu uuuu

0Bh,8Bh,

10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

81h,181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0 1111 1111 1111 1111

Legend: x = unknown, u = unchanged, - = unimplemented locations read as ‘0’. Shaded cells are not used by Timer0.

PIC16F818/819

DS39598E-page 56  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 57

PIC16F818/819

7.0 TIMER1 MODULE

The Timer1 module is a 16-bi t tim er/c ou nter cons is tin g

of two 8-bit registers (TMR1H and TMR1L) which are

readable and writable. The TMR1 register pair

(TMR1H:TMR1L) increments from 0000h to FFFFh

and rol ls over to 0000h. Th e TMR1 inter rupt, if e nabled,

is generated on overflow which is latched in interrupt

flag bit, TMR1IF (PIR1<0>). This interrupt can be

enabled/disabled by setting/clearing TMR1 Interrupt

Enable bit, TMR1IE (PIE1<0>).

Timer1 can also be used to provide Real-Time Clock

(RTC) functionality to applications with only a minimal

addition of external components and code overhead.

7.1 Timer1 Operation

Timer1 can operate in one of three modes:

•as a timer

• as a synchronous counter

• as an asynchronous counter

The operating mode is determined by the clock select

bit, TMR1CS (T1CON<1>).

In Timer mode, Timer1 increments every instruction

cycle. In Counter mode, it increments on every rising

edge of the external clock input.

Timer1 can be enabled/disabled by setting/clearing

control bit, TMR1ON (T1CON<0>).

Timer1 also has an internal “Reset input”. This Reset

can be generated by the CCP1 module as the special

event trigger (see Section 9.1 “Capture Mode”).

When the Timer1 oscillator is enabled (T1OSCEN is

set), the RB6/T1OSO/T1CKI/PGC and RB7/T1OSI/

PGD pins become inputs. That is, the TRISB<7:6>

value is ignored and these pins read as ‘0’.

Additional information on timer modules is available in

the “PICmicro® Mid-Range MCU Family Reference

Manual” (DS33023).

U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

—— T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON

bit 7 bit 0

bit 7-6 Unimplemented: Read as ‘0’

bit 5-4 T1CKPS1:T1CKPS0: 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: Timer1 Oscillator Enable Control bit

1 = Oscillator is enabl ed

0 = Oscillator is shut-off (the oscillator inverter is turned off to eliminate power drain)

bit 2 T1SYNC: Timer1 External Clock Input Synchroniz ation Control bit

TMR1CS = 1:

1 = Do not synchronize external clock input

0 = Synchronize external clock input

TMR1CS = 0:

This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.

bit 1 TMR1CS: Timer1 Clock S ourc e Select bit

1 = External clock from pin RB6/T1OSO/T1CKI/PGC (on the rising edge)

0 = Internal clock (FOSC/4)

bit 0 TMR1ON: Timer1 On bit

1 = Enables Timer1

0 =Stops Timer1

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PIC16F818/819

DS39598E-page 58  2004 Microchip Technology Inc.

7.2 Timer1 Operation in Timer Mode

Timer mode is selected by clearing the TMR1CS

(T1CON<1>) bit. In this mode, the input clock to the

timer is FOSC/4. The synchronize control bit, T1SYNC

(T1CON<2>), has no effect since the internal clock is

always in sync.

7.3 Timer1 Counter Operation

Timer1 may operate in Asynchronous or Synchronous

mode depending on the setting of the TMR1CS bit.

When Timer1 is being incremented via an external

source, increments occur on a rising edg e. After Timer1

is enab led in Coun ter mode, the module must first have

a falling edge before the counter begins to increment.

7.4 Timer1 Operation in Synchr onized

Counter Mode

Counter mode is selected by setting bit TMR1CS. In

this mode, the timer increments on every rising edge of

clock input on pin RB7/T1OSI/PGD when bit

T1OSCEN is set, or on pin RB6/T1OSO/T1CKI/PGC

when bit T1OSCEN is cleared.

If T1SYNC is cleared, then the external clock input is

synchronized with internal phase clocks. The synchro-

nization is done after the prescaler stage. The

prescaler stage is an asynchronous ripple counter.

In this configuration, during Sleep mode, T imer1 will not

increment even if the external clock is present, since

the synchronization circuit is shut-off. The prescaler,

however, will continue to increment.

FIGURE 7-1: TIMER1 INCREMENTING EDGE

FIGURE 7-2: TIMER1 BLOCK DIAGRAM

T1CKI

(Default High)

T1CKI

(Default Low)

Note: Arrows indicate counter increments.

TMR1H TMR1L

T1OSC T1SYNC

TMR1CS

T1CKPS1:T1CKPS0 Q Clock

T1OSCEN

Enable

Oscillator(1)

FOSC/4

Internal

Clock

TMR1ON

On/Off

Prescaler

1, 2, 4, 8 Synchronize

det

Synchronized

Clock Input

RB7/T1OSI/PGD

RB6/T1OSO/T1CKI/PGC

Note 1: W hen the T1OSCEN bit is cleared, the inverter is turned off. This eliminates power drain.

Set Flag bit

TMR1IF on

Overflow TMR1

 2004 Microchip Technology Inc. DS39598E-page 59

PIC16F818/819

7.5 Timer1 Operation in

Asynchronous Counter Mode

If control bi t, T1SYNC (T1CON<2>), is set, th e external

clock input is not synchronized. The timer continues to

increment asynchronous to the internal phase clocks.

The timer will continue to run during Sleep and can

generate an interrupt on overflow that will wake-up the

processor. However, special precautions in software

are needed to read/write the timer.

In Asynchronous Counter mode, Timer1 cannot be

used as a time base for capture or compare operations.

7.5.1 READING AND WRITING TIMER1

IN ASYNCHRONOUS COUNTER

MODE

Reading TMR1H or TMR1L while the timer is running

from an e xternal asyn chronous cl ock will ens ure a valid

read (taken care of in hardware). However, the user

should keep i n mind that rea ding t he 16-bi t time r in tw o

8-bit values itself poses certain problems, since the

timer may overflow between the reads.

For writes , it is re commend ed that th e user s imply sto p

the timer and write the desired values. A write conten-

tion may occur by writing to the timer reg isters while the

unpredictabl e value in the timer register.

Reading the 16-bit value requires some care. The

example codes provided in Example 7-1 and

Example 7-2 demonstrate how to write to and read

Timer1 while it is running in Asynchronous mode.

EXAMPLE 7-1: WRITING A 16-BIT FREE RUNNING TIMER

EXAMPLE 7-2: READING A 16-BIT FREE RUNNING TIMER

; All interrupts are disabled

CLRF TMR1L ; Clear Low byte, Ensures no rollover into TMR1H

MOVLW HI_BYTE ; Value to load into TMR1H

MOVWF TMR1H, F ; Write High byte

MOVLW LO_BYTE ; Value to load into TMR1L

MOVWF TMR1H, F ; Write Low byte

; Re-enable the Interrupt (if required)

CONTINUE ; Continue with your code

; All interrupts are disabled

MOVF TMR1H, W ; Read high byte

MOVWF TMPH

MOVF TMR1L, W ; Read low byte

MOVWF TMPL

MOVF TMR1H, W ; Read high byte

SUBWF TMPH, W ; Sub 1st read with 2nd read

BTFSC STATUS, Z ; Is result = 0

GOTO CONTINUE ; Good 16-bit read

; TMR1L may have rolled over between the read of the high and low bytes.

; Reading the high and low bytes now will read a good value.

MOVF TMR1H, W ; Read high byte

MOVWF TMPH

MOVF TMR1L, W ; Read low byte

MOVWF TMPL ; Re-enable the Interrupt (if required)

CONTINUE ; Continue with your code

PIC16F818/819

DS39598E-page 60  2004 Microchip Technology Inc.

7.6 Timer1 Oscillator

A crystal oscillator circu it is built-in between pins T1OSI

(input) and T1OSO (amplifier output). It is enabled by

setting control bit, T1OSCEN (T1CON<3>). The

oscillator is a low-power oscillator, rated up to

32.768 kHz. It will continue to run during Sleep. It is

primaril y i nte nded for a 3 2 k H z cr y st a l. T he circ ui t fo r a

typical LP oscillator is shown in Figure 7-3. Table 7-1

shows th e cap aci tor sel ection for the Timer1 o scillato r.

The user m us t pro vi de a sof tware time del ay to en su re

proper oscillator start-up.

FIGURE 7-3: EXTERNAL

COMPONENTS FOR THE

TIMER1 LP OSCILLATOR

T ABLE 7-1: CAPACITOR SELECTION FOR

THE TIMER1 OSCILLATOR

7.7 Timer1 Oscillator Layout

Considerations

The Timer1 oscillator circuit draws very little power

during operation. Due to the low-power nature of the

oscillator, it may also be sensitive to rapidly changing

signals in close proximity.

The oscillator circuit, shown in Figure 7-3, should be

located as close as possible to the microcontroller.

There sho uld be no circu its pas sing within the oscillator

circuit boundaries other than VSS or VDD.

If a high-spee d c irc ui t mus t b e l oc ate d n ear the osc ill a-

tor, a grounded guard ring around the oscillator circuit,

as shown in Figure 7-4, may be helpful when used on

a single-sided PCB or in addition to a ground plane.

FIGURE 7-4: OSCILLATOR CIRCUIT

WITH GROUNDED

GUARD RING

Note: The Timer1 oscillator shares the T1OSI

and T1OSO pins with the PGD and PGC

pins used for programming and

debugging.

When usi ng th e Timer1 osci ll at or, In-Circu it

Serial Programming™ (ICSP™) may not

function correctly (high-voltage or low-

voltage) or the In-Circuit Debugger (ICD)

may not communicate with the controller.

As a result of using eit her ICSP or ICD, the

T imer1 crystal may be damaged.

If ICSP or ICD operatio ns are requi red, the

crystal should be disconnected from the

circuit (disconnect either lead) or installed

after programming. The oscillator loading

capacitors may remain in-circuit during

ICSP or ICD operation.

PIC16F818/819

T1OSI

T1OSO

33 pF

XTAL

32.768 kHz

Note: See the Notes with Table 7-1 for additional

information about capacitor selection.

Osc Type Freq C1 C2

LP 32 kHz 33 pF 33 pF

Note 1: Microchip suggests this value as a starting

point in vali dating the oscillator circuit.

2: Higher capacit ance inc reases the st abilit y

of the oscillator but also increases the

start-up time.

3: Since each resonator/crystal has its own

characteristics, the user should consult

the resonator/crystal manufacturer for

appropriate values of external

components.

4: Capacitor values are for design guidance

only.

OSC1

VSS

OSC2

RB7

RB6

RB5

 2004 Microchip Technology Inc. DS39598E-page 61

PIC16F818/819

7.8 Resetting Timer1 Using a CCP

Trigger Output

If the CCP1 module is configured in Compare mode to

generate a “special event trigger” signal

(CCP1M3:CCP1M0 = 1011), the signal will reset

Timer1 and start an A/D conversion (if the A/D module

is enabled).

T ime r1 must be c onfigured fo r either T ime r or Synchro-

nized Counter mode to take advantage of this feature.

If Timer1 is running in Asynchronous Counter mode,

this Reset operation may not work.

In the event that a write to Timer1 coincides with a

special event trigger from CCP1, the write will take

precedence.

In this mode of operation, the CCPR1H:CCPR1L

Timer1.

7.9 Resetting Timer1 Register Pair

(TMR1H , TMR1 L)

TMR1H an d TMR1L reg isters are not rese t to 00h on a

POR or any other Reset, except by the CCP1 special

event triggers.

T1CON re gister is rese t to 00h on a Pow er-on Rese t or

a Brown-out Reset, which shuts off the timer and

leaves a 1:1 prescale. In all other Resets, the register

is unaffected.

7.10 Timer1 Prescaler

The prescaler counter is cleared on writes to the

TMR1H or TMR1L registers.

7.11 Using Timer1 as a

Real-Time Clock

Adding an extern al LP os cilla tor to Timer1 (such as th e

one described in Section 7.6 “Timer1 Oscillator”),

gives users the option to include RTC functionality in

their applications. This is accomplished with an inex-

pensive watch crystal to provide an accurate time base

and several lines of application code to calculate the

time. When operating in Sleep mode and using a

battery or supercapacitor as a power source, it can

completely eliminate the need for a separate RTC

device and battery backup.

The application code routine, RTCisr, shown in

Example 7-3, demonstrates a simple method to

increment a counter at one-second intervals using an

Interrupt Service Routine. Incrementing the TMR1

the routine which increments the seconds counter by

one; additional counters for minutes and hours are

inc remented as the previous counter overflows.

Since the register pair is 16 bits wide, counting up to

overflow the register directly from a 32.768 kHz clock

would take 2 seconds. To force the overflow at the

required one-second intervals, it is necessary to pre-

load it; th e simplest method is to set the MSb of TMR1H

with a BSF instruction. Note that the TMR1L register is

never preloaded or altered; doing so may introduce

cumulative erro r over many cycles.

For this method to be accurate, Timer1 must operate in

Asynchrono us mode and the Timer1 overflow int errupt

must be enabled (PIE1<0> = 1) as shown in the routine,

RTCinit. The Timer1 oscillator must also be en abled

and running at all times.

PIC16F818/819

DS39598E-page 62  2004 Microchip Technology Inc.

EXAMPLE 7-3: IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE

TABLE 7-2: REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER

RTCinit BANKSEL TMR1H

MOVLW 0x80 ; Preload TMR1 register pair

MOVWF TMR1H ; for 1 second overflow

CLRF TMR1L

MOVLW b’00001111’ ; Configure for external clock,

MOVWF T1CON ; Asynchronous operation, external oscillator

CLRF secs ; Initialize timekeeping registers

CLRF mins

MOVLW .12

MOVWF hours

BANKSEL PIE1

BSF PIE1, TMR1IE ; Enable Timer1 interrupt

RETURN

RTCisr BANKSEL TMR1H

BSF TMR1H, 7 ; Preload for 1 sec overflow

BCF PIR1, TMR1IF ; Clear interrupt flag

INCF secs, F ; Increment seconds

MOVF secs, w

SUBLW .60

BTFSS STATUS, Z ; 60 seconds elapsed?

RETURN ; No, done

CLRF seconds ; Clear seconds

INCF mins, f ; Increment minutes

MOVF mins, w

SUBLW .60

BTFSS STATUS, Z ; 60 seconds elapsed?

RETURN ; No, done

CLRF mins ; Clear minutes

INCF hours, f ; Increment hours

MOVF hours, w

SUBLW .24

BTFSS STATUS, Z ; 24 hours elapsed?

RETURN ; No, done

CLRF hours ; Clear hours

RETURN ; Done

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

0Bh,8Bh,

10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF — — SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE — — SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

0Eh TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu

0Fh TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu

10h T1CON —— T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.

 2004 Microchip Technology Inc. DS39598E-page 63

PIC16F818/819

8.0 TIMER2 MODULE

Timer2 is an 8-bit timer with a prescaler and a

post scaler . It can be used as the PWM time base for the

PWM mod e of the C CP1 modul e. The TMR2 register i s

readable and writable and is cleared on any device

Reset.

The in put cloc k (FOSC/4) has a prescale option of 1:1,

1:4 or 1:16, selected by control bits,

T2CKPS1:T2CKPS0 (T2CON<1: 0>).

The Timer2 module has an 8-bit period register, PR2.

Timer2 increments from 00h until it matches PR2 and

then resets to 00h on the next increment cycle. PR2 is

a readable and writable register. The PR2 register is

initialized to FFh upon Reset.

The match output of TMR2 goes through a 4-bit

postscaler (which gives a 1:1 to 1:16 scaling inclusive)

to generate a TMR2 interrupt (latched in flag bit,

TMR2IF (PIR1<1>)).

T imer2 can b e shut-of f by clearing control bit, T MR2ON

(T2CON<2>), to mini mize power consumpti on.

Additional information on timer modules is available in

the “PICmicro® Mid-Range MCU Family Reference

Manual” (DS33023).

8.1 Timer2 Prescaler and Postscaler

The prescaler and postscaler counters are cleared

when any of the following occurs:

• A write to the TMR2 register

• A write to the T2CON register

• Any devic e R ese t (P ower-o n Re se t, MCL R, WDT

Reset or Brown-out Reset)

TMR2 is not cleared when T2CON is written.

8.2 Output of TMR2

The output of TMR2 (before the post scaler) is fed to the

Synchron ous Seria l Port m odu le whi ch op tio nal ly use s

it to generate a shift clock.

FIGURE 8-1: TIMER2 BLOCK DIAGRAM

Comparator

TMR2

Sets Flag

TMR2 reg

Output(1)

Reset

Postscaler

Prescaler

PR2 reg

FOSC/4

1:1 1:16

1:1, 1:4, 1: 1 6

bit TMR2IF

Note 1: TMR2 register output can be software

selected by the SSP module as a baud clock.

PIC16F818/819

DS39598E-page 64  2004 Microchip Technology Inc.

TABLE 8-1: REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER

U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0

bit 7 bit 0

bit 7 Unimplemented: Read as ‘0’

bit 6-3 TOUTPS3:TOUTPS0: Timer2 Output Postscale Select bits

0000 =1:1 Postscale

0001 =1:2 Postscale

0010 =1:3 Postscale

•

1111 =1:16 Postscale

bit 2 TMR2ON: Timer2 On bit

1 = Timer2 is on

0 = Timer2 is off

bit 1-0 T2CKPS1:T2CKPS0: Timer2 Clock Prescale Select bits

00 = Prescaler is 1

01 = Prescaler is 4

1x = Prescaler is 16

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

Addres s Nam e B it 7 Bit 6 B it 5 B i t 4 B it 3 Bit 2 B it 1 B it 0 Value on

POR, BOR

Value on

all other

Resets

0Bh, 8Bh,

10Bh, 18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF — — SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE — — SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

11h TMR2 Timer2 Module Register 0000 0000 0000 0000

12h T2CON — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000

92h P R2 Timer2 Period Register 1111 1111 1111 1111

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.

 2004 Microchip Technology Inc. DS39598E-page 65

PIC16F818/819

9.0 CAPTURE/COMPARE/ PWM

(CCP) MODULE

The Cap ture /C omp are/PW M (CC P) m od ule co nt ai ns a

16-bit register that can operate as a:

• 16-bit Capture register

• 16-bit Compare register

• PWM Master/Slave Duty Cycle r egister

Table 9-1 shows the timer resources of the CCP

module modes.

Capture/Compare/PWM Register 1 (CCPR1) is com-

prised of two 8-bit registers: CCPR1L (low byte) and

CCPR1H (high byte). The CCP1CON register controls

the operation of CCP1. The special event trigger is

generate d by a comp are match whic h will reset T i mer1

and start an A/D conversion (if the A/D module is

enabled).

The CCP module’s input/output pin (CCP1) can be

configu red as RB2 or RB3. This selec tion is s et in bit 1 2

(CCPMX) of the Configuration Word register.

Additional information on the CCP module is available

in the “PICmicro® Mid-Range MCU Family Reference

Manual” (DS33023) and in Application Note AN594,

“Using the CCP Module(s)” (DS00594).

TABLE 9-1: CCP MODE – TIMER

RESOURCE

CCP Mode Timer Resource

Capture

Compare

PWM

Timer1

Timer2

U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

—— CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0

bit 7 bit 0

bit 7-6 Unimplemented: Read as ‘0’

bit 5-4 CCP1X:CCP1Y: PWM Least Significant bits

Capture mo de:

Unused.

Compare mode:

Unused.

PWM mode:

These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPRxL.

bit 3-0 CCP1M3:CCP1M0: CCP1 Mode Select bits

0000 = Capture/Compare/PWM disabled (resets CCP1 module)

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, set output on match (CCP1IF bit is set)

1001 = Compare mode, clear output on match (CCP1IF bi t is set)

1010 = Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin is

unaffected)

1011 = Compare mode, trigger special event (CCP1IF bit is set, CCP1 pin is unaffected);

CCP1 resets TMR1 and starts an A/D conversion (if A/D module is enabled)

11xx =PWM mode

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PIC16F818/819

DS39598E-page 66  2004 Microchip Technology Inc.

9.1 Capture Mode

In Capture mode, CCPR1H:CCPR1L captures the

16-bit val ue of the TMR1 register when an event occurs

on the CCP1 pin. An event is defined as:

• Every falling edge

• Every rising edge

• Every 4th rising edge

• Every 16th rising edge

An even t is selec ted by c ontrol bit s, CCP1 M3:CCP1M0

(CCP1CON<3:0>). When a capture is made, the inter-

rupt request flag bit, CCP1IF (PIR1<2>), is set. It must

be cleared in software. If another capture occurs before

the value in register CCPR1 is read, the old captured

value is overwritten by the new captured value.

9.1.1 CCP PIN CONFIGURATION

In Capture mode, the CCP1 pin should be configured

as an input by setting the TRISB<x> bit.

FIGURE 9-1: CAPTURE MODE

OPERATION BLOCK

DIAGRAM

9.1.2 TIMER1 MODE SELECTION

Timer1 must be running in Timer mode or Synchro-

nized Counter mode for the CCP module to use the

capture feature. In Asynchronous Counter mode, the

capture operation may not work.

9.1.3 SOFTWARE INTERRUPT

When the Capture mode is changed, a false capture

interrupt may be generated. The user should keep bit,

CCP1IE (PIE1<2>), clear to avoid false interrupts and

should clear the flag bit, CCP1IF, following any such

change in ope rati ng mod e.

9.1.4 CCP PRESCALER

There are four prescaler settings specified by bits

CCP1M3:CCP1M0. Whenever the CCP module is

turned off, or the CCP module is not in Capture mode,

the prescaler counter is cleared. This means that any

Reset will clear the prescaler counter.

Switching from one capture prescaler to another may

generate an interrupt. Also, the prescaler counter will

not be cleared; there fore, the firs t capture ma y be from

a non-zero prescaler. Example 9-1 shows the

recommended method for switching between capture

prescalers. This example also clears the prescaler

counter and will not generate the “false” interrupt.

EXAMPLE 9-1: CHANGIN G BETWEEN

CAPTURE PRESCALERS

Note 1: If the CCP1 pin is configured as an

output, a write to the port can cause a

capture co ndition.

2: The TR ISB b it (2 o r 3 ) is d epe ndent upo n

the setting of configuration bit 12

(CCPMX).

CCPR1H CCPR1L

TMR1H TMR1L

Set Flag bit CCP1IF

(PIR1<2>)

Capture

Enable

Q’s CCP1CON<3:0>

CCP1 pin

Prescaler

÷ 1, 4, 16

and

Edge Dete ct

CLRF CCP1CON ;Turn CCP module off

MOVLW NEW_CAPT_PS ;Load the W reg with

;the new prescaler

;move value and CCP ON

MOVWF CCP1CON ;Load CCP1CON with this

;value

 2004 Microchip Technology Inc. DS39598E-page 67

PIC16F818/819

9.2 Compare Mode

In C ompare mo de, t he 16- bit CC PR1 re gist er va lue is

constantly compared against the TMR1 register pair

value. When a match occurs, the CCP1 pin is:

• Driven high

•Driven low

• Remains unchanged

The action on the pin is based on the value of control

bits, CCP1M3:CCP1M0 (CCP1CON<3:0>). At the

same time, interrupt flag bit CCP1IF is set.

FIGURE 9-2: COMPARE MODE

OPERATION BLOCK

DIAGRAM

9.2.1 CCP PIN CONFIGURATION

The user m us t co nfig ure t he CC P1 p in a s an outp ut b y

clearing the TRISB<x> bit.

9.2.2 TIMER1 MODE SELECTION

Timer1 must be running in Timer mode or Synchro-

nized Counter mode if the CCP module is using the

compare feature. In Asynchronous Counter mode, the

compare operation may not work.

9.2.3 SOFTWARE INTERRUPT MODE

When genera te software in terrupt is chose n, the CCP1

pin is not af fected. On ly a CCP interrupt is generated (if

enabled).

9.2.4 SPECIAL EVENT TRIGGER

In this mode, an internal hardware trigger is generated

that may be used to initiate an action.

The special event trigger output of CCP1 resets the

TMR1 regis ter p ai r and starts an A/D co nv ersi on (if th e

A/D module is enabled). This allows the CCPR1

TABLE 9-2: REGISTERS ASSOCIATED WITH CAPTURE, COMPARE AND TIMER1

CCPR1H CCPR1L

TMR1H TMR1L

Comparator

ROutput

Logic

Special Event Trigger

Set Flag bit CCP1IF

(PIR1<2>)

Match

CCP1 pin

TRISB<x> CCP1CON<3:0>

Mode Select

Output Enable

Special event trigger will:

• Reset Timer1 but not set interrupt flag bit, TMR1IF

(PIR1<0>)

• Set GO/DONE bit (ADCON0<2>) which starts an A/D

conversion

Note 1: Clearing the CC P1CON registe r will forc e

the CCP1 compare output latch to the

default low level. This is not the data

latch.

2: The TR ISB b it (2 o r 3) is d epe nde nt upon

the setting of configuration bit 12

(CCPMX).

Note: The special event trigger from the CCP1

module will not set interrupt flag bit,

TMR1IF (PIR1<0>).

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

0Bh,8Bh

10BH,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF — — SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE — — SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

86h TRISB PORTB Data Direction Register 1111 1111 1111 1111

0Eh TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu

0Fh TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu

10h T1CON —— T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON --00 0000 --uu uuuu

15h CCPR1L Capture/Compare/PW M Regist er 1 (LSB) xxxx xxxx uuuu uuuu

16h CCPR1H Capture/Compare/PWM Register 1 (MSB ) xxxx xxxx uuuu uuuu

17h CCP1CON — — CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by Capture and Timer1.

PIC16F818/819

DS39598E-page 68  2004 Microchip Technology Inc.

9.3 PWM Mode

In Pulse -Width Modulati on (PWM) mode , the CCP1 pin

produces up to a 10-bit resolution PWM output. Since

the CCP1 pi n is multiplexed with the PORTB da ta latch,

the TRISB<x> bit must be cleared to make the CCP1

pin an output.

Figure 9-3 shows a simplified block diagram of the

CCP module in PWM mo de.

For a st ep by step pr ocedure on h ow to set up the CCP

module for PWM operation, see Section 9.3.3 “Setup

for PWM Operatio n”.

FIGURE 9-3: SIMPLIFIED PWM BLOCK

DIAGRAM

A PWM output (Figure 9-4) has a time base (period)

and a time that the output stays high (duty cycle). The

frequency of the PWM is the inverse of the period

(1/period).

FIGURE 9-4: PWM OUTPUT

9.3.1 PWM PE RIOD

The PWM period is specified by writing to the PR2

following formula.

EQUATION 9-1:

PWM frequency is defined as 1/[PWM period].

When TM R2 is equal to PR2, t he following three event s

occur on the next increment cycle:

•TMR2 is cleared

• The CCP1 pin is set (exception: if PWM duty

cycle = 0%, the CCP1 pin will not be set)

• The PWM duty cycle is latched from C CPR1L into

CCPR1H

9.3.2 PWM DUTY CYCLE

The PWM duty cycle is specified by writing to the

CCPR1L register and to the CCP1CON<5:4> bits. Up

to 10- b i t re so l uti on is av ai l ab le. T he CC PR 1 L c ontai ns

the eight MSbs and the CCP1CON<5:4> contains the

two LSbs. This 10-bit value is represented by

CCPR1L:CCP1CON<5:4>. The following equation is

used to calculate the PWM duty cycle in time.

EQUATION 9-2:

CCPR1L and CCP1CON<5:4> can be written to at any

time but the duty cycle value is not latched into

CCPR1H until after a match between PR2 and TMR2

occurs (i.e., the period is complete). In PWM mode,

CCPR1H is a read-only register.

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.

When the CCPR1H and 2-bit latch match TMR2,

concatenated with an internal 2-bit Q clock or 2 bits of

the TMR2 prescaler, the CCP1 pin is cleared.

Note: Clearing the CCP1CON register will force

the CCP1 PWM o utpu t latch to th e de fau lt

low l evel. This is not t he PO RTB I/ O data

latch.

CCPR1L

CCPR1H (Slave)

Comparator

TMR2

Comparator

PR2

(Note 1)

Duty Cycle Registers CCP1CON<5:4>

Clear Timer,

CCP1 pin and

latch D.C.

TRISB<x>

CCP1 pin

Note 1: 8-bit timer is concatenated with 2-bit int ernal Q clock

or 2 bit s of the prescaler to cr eate 10-bit time base.

Period

Duty Cycle

TMR2 = PR2

TMR2 = Duty Cycle

TMR2 = PR 2

Note: The Timer2 postscaler (see Section 8.0

“Timer2 Module”) is not used in the

determination of the PWM frequency. The

postscaler could be used to have a servo

update rate at a different frequency than

the PWM output.

PWM Period = [(PR2) + 1] • 4 • TOSC •

(TMR2 Pres cal e Value)

PWM Duty Cycle = (CCPR1L:CCP1CON<5:4>) •

TOSC • (TMR2 Pr escale Value)

 2004 Microchip Technology Inc. DS39598E-page 69

PIC16F818/819

The ma ximum P WM res olut ion (b its) fo r a giv en PWM

frequency is given by the following formula.

EQUATION 9-3:

9.3.3 SETUP FOR PWM OPERATION

The following steps should be taken when configuring

the CCP module for PWM operation:

1. Set the PWM pe riod by writing to the PR2 register.

2. Set the PWM duty cycle by writing to the

CCPR1L register and CCP1CON<5:4> bits.

3. Make the CCP1 pin an output by clearing the

TRISB<x> bit.

4. Set the TMR2 prescale value and enab le Timer2

by writing to T2CON.

5. Configure th e CCP1 module for PWM operatio n.

TABLE 9-3: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 20 MHz

TABLE 9-4: REGISTERS ASSOCIATED WITH PWM AND TIMER2

Note: If the PWM duty cycle value is longer than

the PWM period, the CCP1 pin will not be

cleared.

log(FPWM

log(2)

FOSC )bits

Resolution

Note: The TRISB bit (2 or 3) is dependant upon

the setting of configuration bit 12

(CCPMX).

PWM Frequency 1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz

Timer Prescaler (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 5.5

Ad d r ess 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

0Bh,8Bh

10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF — — SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE — — SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

86h TRISB PORTB Data Direction Register 1111 1111 1111 1111

11h TMR2 T imer2 Module Register 0000 0000 0000 0000

92h PR2 Ti mer2 Modul e Period Reg ister 1111 1111 1111 1111

12h T2CON — TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000

15h CCPR1L C apture /Comp ar e/PWM Regist er 1 (LSB) xxxx xxxx uuuu uuuu

16h CCPR1H Capture/Compar e/ PWM Register 1 (MSB) xxxx xxxx uuuu uuuu

17h CCP1CON —— CCP1X CCP1Y CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by PWM and Timer2.

PIC16F818/819

DS39598E-page 70  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 71

PIC16F818/819

10.0 SYNCHRONOUS SERIAL PORT

(SSP) MODULE

10.1 SSP Module Overview

The Synchronous Serial Port (SSP) module is a serial

interface useful for communicating with other periph-

eral or microcontroller devices. These peripheral

devices may be serial EEPROMs, shift registers,

display drivers, A/D converters, etc. The SSP module

can operate in one of two modes:

• Serial Peripheral Interface (SPI)

• Inter-Integrated Circuit (I2C)

An overview of I2C operations and additional informa-

tion on th e SSP module can be fo und in the “PICmicro®

Mid-Range MCU Family Reference Manual”

(DS33023).

Refer to Application Note AN578, “Use of the SSP

Module in the I2C™ Multi-Master Environment”

(DS00578).

10.2 SPI Mode

This section contains register definitions and

operational characteristics of the SPI module.

SPI mode allows 8 bits of data to be synchronously

transmitted and received simultaneously. To

accomplish communication, typically three pins are

used:

• Serial Data Out (SDO) RB2/SDO/CCP1

• Serial Data In (SDI) RB1/SDI/SDA

• Serial Clock (SCK) RB4/SCK/SCL

Additionally, a fourth pin may be used when in a Slave

mode of operation:

• Slave Select (SS) RB5/SS

When initializing the SPI, several options need to be

specified. This is done by programming the appropriate

control bits in the SSPCON register (SSPCON<5:0>)

and the SSPSTAT register (SSPSTAT<7:6>). These

control bits allow the following to be specified:

• Master mode (SCK is the clock output)

• Slave mode (SCK is the clock input)

• Clock Polarity (Idle state of SCK)

• Clock Edge (output data on rising/falling

edge of SCK)

• Clock Rate (Master mode only)

• Slave Select mode (Slave mode only)

Note: Before enabling the module in SPI Slave

mode, the state of the clock line (SCK)

must match the polarity selected for the

Idle state. The clock line can be observed

by read ing the SCK pin. The pola rity of th e

Idle state is determined by the CKP bit

(SSPCON<4>).

PIC16F818/819

DS39598E-page 72  2004 Microchip Technology Inc.

R/W-0 R/W-0 R-0 R-0 R-0 R-0 R-0 R-0

SMP CKE D/A PSR/WUA BF

bit 7 bit 0

bit 7 SMP: SPI Data Input Sample Phase bit

SPI Mast e r mode:

1 = Input data sampled at end of data output time

0 = Input data sampled at middle of data output time (Microwire)

SPI Slave mode:

This bit must be cleared when SPI is used in Slave mode.

I2 C mode:

This bit must be maintained clear.

bit 6 CKE: SPI Clock Edge Select bit

1 = Transmit occurs on transition from active to Idle clock state

0 = Transmit occurs on transition from Idle to active clock state

Note: Polarity of clock state is set by the CKP bit (SSPCON<4>).

I2 C mode:

This bit must be maintained clear.

bit 5 D/A: Data/Address bit (I2C mode only)

In I2 C Slave mode:

1 = Indicates that the last byte received was data

0 = Indicates that the last byte received was address

bit 4 P: Stop bit(1) (I2C mode only)

1 = Indicates that a Stop bit has been detected last

0 = Stop bit was not detected last

bit 3 S: Start bit(1) (I2C mode only)

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 Inform ati on bit (I2C mode only)

Holds the R/W bit information following the last address match and is only valid from address

match to the next Start bit, Stop bit or ACK bit.

1 =Read

0 = Write

bit 1 UA: Update Address bit (10-bit I2C mode only)

1 = Indicates that the user needs to update the address in the SSPADD 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, SSPBUF is full

0 = Receive not complete, SSPBUF is empty

Transmit (In I2 C mo de onl y):

1 = Transmit in progress, SSPBUF is full (8 bits)

0 = Transmit complete, SSPBUF is empty

Note 1: This bit is cl eared when the SSP module is dis abled (i.e., the SSPEN b it is cleared).

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

 2004 Microchip Technology Inc. DS39598E-page 73

PIC16F818/819

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0

bit 7 bit 0

bit 7 WCOL: Write Collision Detect bit

1 = An attempt to write the SSPBUF register failed because the SSP module is busy

(must be cleared in software)

0 = No collision

bit 6 SSPOV: Receive Overflow Indicator bit

In SPI mode:

1 = A ne w byte is rec eive d while t he SSPBUF regi ster is st ill hol ding t he pr evious d ata . In cas e

of overflow, the data in SSPSR is lost. Overflow can only occur in Slave mode. The user

must read the SSPBUF, even if only transmitting data, to avoid setting overflow. In Master

mode, the o verflow bi t is not set sinc e each new rec eption (and transmiss ion) is ini tiated by

writing to the SSPBUF register.

0 = No over flow

In I2 C mode:

1 = A byt e is received wh ile the SSPBUF reg ister is stil l holdin g the previous byte. SSPOV is a

“don’t care” in Transmit mode. SSPOV must be cleared in software in either mode.

0 = No over flow

bit 5 SSPEN: Synchronous Serial Port Enable bit(1)

In SPI mode:

1 = Enables serial port and configures SCK, SDO and SDI as serial port pins

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 serial port pins

0 = Disables serial port and configures these pins as I/O port pins

Note 1: In both modes, when enabled, these pins must be properly configured as input or

output.

bit 4 CKP: Clock Polarity Select bit

In SPI mode:

1 = T rans mit ha ppens on fallin g edge, re ceive on risin g edge. Id le st ate for cl ock is a high le vel.

0 = Transmit happens on rising edge, receive on falling edge. Idle state for clock is a low level.

In I2 C Slave mode:

SCK release control.

1 = Enable clock

0 = Holds clock low (clock stretch). (Used to ensure data setup time.)

bit 3-0 SSPM<3:0>: Synchronous Serial Port Mode Select bits

0000 = SPI Master mode, clock = OSC/4

0001 = SPI Master mode, clock = OSC/16

0010 = SPI Master mode, clock = OSC/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 =I

2C Slave mode, 7-bit address

0111 =I

2C Slave mode, 10-bit address

1011 =I

2C Firmware Controlled Master mode (Slave Idle)

1110 =I

2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled

1111 =I

2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled

1000, 1001, 1010, 1100, 1101 = Reserved

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PIC16F818/819

DS39598E-page 74  2004 Microchip Technology Inc.

FIGURE 10-1: SSP BLOCK DIAGRAM

(SPI™ M ODE) To enable the serial port, SSP Enable bit, SSPEN

(SSPCON<5>), must be set. To reset or reconfigure

SPI mode, clear bit SSPEN, reinitialize the SSPCON

SDI, SDO, SCK and SS pins as serial port pins. Fo r the

pins to behave as the serial port function, they must

have their data direction bits (in the TRISB register)

appropriately programmed. That is:

• SDI must have TRISB<1> set

• SDO must have TRISB<2> cleared

• SCK (Master mode) must have TRISB<4> cleared

• SCK (Slave mode) must have TRISB<4> set

•SS

must have TRISB<5> set

TABLE 10-1: REGISTERS ASSOCIATED WITH SPI™ OPERATION

Read Write

Internal

Data Bus

RB1/SDI/SDA

RB2/SDO/

RB5/SS

RB4/SCK/

SSPSR reg

SSPBUF reg

SSPM3:SSPM0

bit 0 Shift

Clock

SS Control

Enable

Edge

Select

Clock Select

TMR2 Output

TCY

Prescaler

4, 16, 64

TRISB<4>

Edge

Select

SCL

CCP1 Note 1: When the SPI is in Slave mode

with the SS pin control enabled

(SSPCON<3:0> = 0100), the SPI module

will reset if the SS pin is set to VDD.

2: If the SPI is used in Slave mode with

CKE = 1, then the SS pin control must be

enabled.

3: When the SPI is in Slave mode

with the SS pin control enabled

(SSPCON<3:0> = 0100), the state of the

SS pin can a ff ect the st ate read back from

the TRISB<2> bit. The peripheral OE

signal from the SSP module into PORTB

controls the state that is read back from

the TRISB<2> bit. If read-modify-write

instructions, such as BSF are performed

on the TRISB register while the SS pin is

high, this will cause the TRISB<2> bit to

be set, thus disabling the SDO output.

Addr e s s N a me Bit 7 Bit 6 Bit 5 B it 4 B it 3 B it 2 Bit 1 Bit 0 Value on

POR, BOR

Value on

all other

Resets

0Bh,8Bh

10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF —— SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE ——SSPIECCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

86h TRISB PO RTB Data Direction Register 1111 1111 1111 1111

13h SSPB UF S ynchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu

14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000

94h SSPSTAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by the SSP in SPI™ mode.

 2004 Microchip Technology Inc. DS39598E-page 75

PIC16F818/819

FIGURE 10-2: SPI™ MODE TIMING, MASTER MODE

FIGURE 10-3: SPI™ MODE TIMING (SLAVE MODE WITH CKE = 0)

FIGURE 10-4: SPI™ MODE TIMING (SLAVE MODE WITH CKE = 1)

SCK (CKP = 0,

SDI (SMP = 0)

SSPIF

bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0

SDI (SMP = 1)

SCK (CKP = 0,

SCK (CKP = 1,

SDO

bit 7

bit 7 bit 0

bit 0

CKE = 0)

CKE = 1)

CKE = 0)

CKE = 1)

SCK (CKP = 0)

SDI (SMP = 0)

SSPIF

bit 7 b i t 6 bi t 5 bit 4 bit 3 bit 2 bi t 1 bit 0

SCK (CKP = 1)

SDO

bit 7 bit 0

SS (Optional)

SCK (CKP = 0)

SDI (SMP = 0)

SSPIF

bit 7 b i t 6 bit 5 bit 4 bit 3 bit 2 b i t 1 bit 0

SCK (CKP = 1)

SDO

bit 7 bit 0

PIC16F818/819

DS39598E-page 76  2004 Microchip Technology Inc.

10.3 SSP I 2C Mode Operation

The SSP module in I2C mod e fully imp lements all slave

functions, except general call support and provides

interr upts on S ta rt and S top bit s in hardware to fac ilitate

firmwa re im ple me nt a tion s of the mast er func tions. The

SSP module implements the standard mode

specifications, as well as 7-bit and 10-bit addressing.

Two pins are used for data transfer. These are the

RB4/SCK/SCL pin, which is the clock (SCL) and the

RB1/SDI/SDA pin, which is the data (SDA). The user

must configure these pins as inputs or outputs through

the TRISB<4,1> bits.

To ensure proper communication of the I2C Slave mode,

the TRIS bits (TRISx [SDA, SCL]) corresponding to the

I2C pin s must be set to ‘1’. If any TRIS bits (TRISx<7:0>)

of the port containing the I2C pins (PORTx [SDA, SCL])

are changed in software during I2C communication

using a Read-Modify-Write instruction (BSF, BCF), then

the I2C mode may stop functioning properly and I2C

communication m ay suspend . Do not chan ge any of the

TRISx bits (TRIS bits of the port cont aining the I2C pins)

using the instruction BSF or BCF during I2C comm unica-

tion. If it is absolutely necessary to change the TRISx

bits during communi cation, the following m ethod ca n be

used:

EXAMPL E 10-1:

The SSP mod ule fun ctions a re enabl ed by settin g SSP

Enable bit, SSPEN (SSPCON<5>).

FIGURE 10-5: SSP BLOCK DIAGRAM

(I2C™ MODE)

The SSP module has five registers for I2C operation:

• SSP Control Register (SSPCON)

• SSP Status Register (SSPSTAT)

• Serial Receive/Transmit Buffer (SSPBUF)

• SSP Shift Register (SSPSR) – Not directly

accessible

• SSP Address Register (SSPADD)

The SSPCON register allows control of the I2C opera-

tion. Four mode selection bits (SSPCON<3:0>) allow

one of the following I2C modes to be selected:

•I

2C Slave mode (7-bit address)

•I

2C Slave mode (10-bit address)

•I

2C Slave mode (7-bit address) with Start and

Stop bit interrupts enabled to support Firmware

Master mode

•I

2C Slave mode (10-bit address) with Start and

Stop bit interrupts enabled to support Firmware

Master mode

•I

2C Firmware Controlled Master mode with Start

and Stop bit interrupts enabled, slave is Idle

Selection of any I2C mode, with the SSPEN bit set,

forces the SCL and SDA pins to be open-drain,

provided these pins are programmed to inputs by

setting the appropriate TRISB bits. Pull-up resistors

must be provided externally to the SCL and SDA pins

for proper operation of the I2C module.

Additional information on SSP I2C operation may be

found in the “PICmicro® Mid-Range MCU Family

Refere nce M anual” (DS33023).

MOVF TRISC, W ; Example for an 18-pin part such as the PIC16F818/819

IORLW 0x18 ; Ensures <4:3> bits are ‘11’

ANDLW B’11111001’ ; Sets <2:1> as output, but will not alter other bits

; User can use their own logic here, such as IORLW, XORLW and ANDLW

MOVWF TRISC

Read Write

SSPSR Reg

Match Detect

SSPADD Reg

Start and

Stop Bit Detect

SSPBUF R e g

Internal

Data Bus

Addr Match

Set, Reset

S, P Bits

(SSPSTAT Reg

)

RB4/SCK/

RB1/

Shift

Clock

MSb

SDI/ LSb

SDA

SCL

 2004 Microchip Technology Inc. DS39598E-page 77

PIC16F818/819

10.3.1 SLAVE MODE

In Slave mod e, the SCL and SDA pins mu st be co nfi g-

ured as in puts (TRISB<4,1> se t). Th e SSP mo du le wil l

override the input state with the output data when

required (sl ave-tra nsmit ter).

When an add ress is match ed, or the d at a trans fer after

an add res s mat ch i s rece ived , th e ha rdw are au tom ati -

cally will generate the Acknowledge (ACK) pulse and

then loa d the SSPBUF re gister wi th th e re ce ive d valu e

currently in the SSPSR register.

Either or both of the following conditions will cause the

SSP module not to give this ACK pul se :

a) The Buffer Full bit, BF (SSPSTAT<0>), was set

before the transfer was received.

b) The overflow bit, SSPOV (SSPCON<6>), was

set before the transfer was received.

In this case, the SSPSR register value is not loaded

into the SSPBUF but bit, SSPIF (PIR1<3>), is set.

Table 10-2 shows what happens when a data transfer

byte is received, given the status of bits BF and

SSPOV. The shaded cells show the condition where

user softw are did not prop erly clear the ove rflow cond i-

tion. Flag bit BF is cleared by reading the SSPBUF

The SCL clock input must have a minimum high and

low fo r pro per op erati on. The h igh and low ti me s o f th e

I2C specification, as well as the requirement of the SSP

module, are shown in timing parameter #100 and

parameter #101.

10.3.1.1 Addressing

Once the SSP module has been enabled, it waits for a

Start condition to occur. Following the Start condition,

the eight bits are shifted into the SSPSR register. All

incoming bits are sampled with the rising edge of the

clock (SCL) line. The value of register SSPSR<7:1> is

compared to the value of the SSPADD register. The

address is compared on the falling edge of the eighth

clock (SCL) pulse. If the addresses match and the BF

and SSPOV bits are clear, the following events occur:

a) The SSPSR register value is loaded into the

SSPBUF register.

b) The Buffer Full bit, BF, is set.

c) An ACK pulse is generated.

d) SSP Interrupt Flag bit, SSPIF (PIR1<3>), is set

(interrupt is generated if enabled) – on the falling

edge of the ninth SCL pulse.

In 10-bit Address mode, two address bytes need to be

received by the slave device. The five Most Significant

bits (MSbs) of the first address byte specify if this is a

10-bit address. Bit R/W (SSPSTAT<2>) must specify a

write so the slave device will receive the second

address by te. Fo r a 10 -bi t add res s, t he fi rst byt e woul d

equal ‘1111 0 A9 A8 0’, where A9 and A8 are the

two MSbs of the address.

The sequence of events for 10-bit address is as

follows, with ste p s 7-9 for slave -tran sm itt er:

1. Receive first (high) byte of address (bits SSPIF,

BF and bit UA (SSPSTAT<1>) are set).

2. Update the SSPADD register with second (low)

byte of address (clears bit UA and releases the

SCL line).

3. Read the SSPBUF register (clears bit BF) and

clear flag bit, SSPIF.

4. Receive second (low) byte of address (bits

SSPIF, BF and UA are set).

5. Update t he SSPADD registe r with the f irst (high)

byte of a ddre ss ; if match rele as es SC L li ne, thi s

will clear bit UA.

6. Read the SSPBUF register (clears bit BF) and

clear flag bit, SSPIF.

7. Receive Repeated Start condition.

8. Receive first (high) byte of address (bits SSPIF

and BF are set).

9. Read the SSPBUF register (clears bit BF) and

clear flag bit, SSPIF.

10.3.1.2 Reception

When the R/W bit of the address byte is clear and an

address match occurs, the R/W bit of the SSPSTAT

the SSPBUF register.

When the address byte overflow condition exists, then

a no Acknowledge (ACK) pulse is given. An overflow

conditi on is in dicated if ei ther bit, BF (SSPSTAT<0>), is

set or bit, SSPOV (SSPCON<6>), is set.

An SSP interrupt is generated for each data transfer

byte. Flag bit, SSPIF (PIR1<3>), must be cleared in

software. The SSPSTAT register is used to determine

the status of the byte.

10.3.1.3 Transmission

When the R/W bit of the incoming address byte is set

and an address match occurs, the R/W bit of the

SSPSTAT register is set. The received address is

loaded into the SSPBUF register. The ACK pulse will

be sent on the ninth bit and pin RB4/SCK/SCL is held

low. The transmit data must be loaded into the

SSPBUF registe r which also load s the SSPSR register .

Then pin RB4/SCK/SCL should be enabled by setting

bit, CKP (SSPCON<4>). The master device must

monitor the SCL pin prior to asserting another clock

pulse. T he slave devices may be h olding of f th e master

device by stretching the clock. 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 (Figure 10-7).

PIC16F818/819

DS39598E-page 78  2004 Microchip Technology Inc.

An SSP interrupt is generated for each data transfer

byte. Flag bit SSPIF must be cleared in software and

the SSPSTAT register is used to determine the status

of the byte. Flag bit SSPIF is set on the falling edge of

the ninth clock pulse.

As a s lave-transm itte r, the AC K puls e from the mas ter-

receiver is latched on the rising edge of the ninth SCL

input pulse. If the SDA line was high (not ACK), then

the dat a tran sfer is com plete. When th e ACK is latched

by the slave device, the slave logic is reset (resets

SSPSTAT register) and the slav e de vice then monitors

for another occurrence of the Start bit. If the SDA line

was low (ACK), the transmit data must be loaded into

the SSPBUF register which also loads the SSPSR

setting bit , CKP.

TABLE 10-2: DATA TRANSFER RECEIVED BYTE ACTIONS

FIGURE 10-6: I2C™ WAVEFORMS FOR RECEPTION (7-BIT ADDRESS)

FIGURE 10-7: I2C™ WAVEFORMS FOR TRANSMISSION (7-BIT ADDRESS)

Status Bits as Data

Transfer is Received SSPSR → SSPBUF Generate ACK Pulse Set bit SSPIF

(SSP interrupt occurs if enabled)

BF SSPOV

00 Yes Yes Yes

10 No No Yes

11 No No Yes

0 1 No No Yes

Note 1: Shaded cells show the conditions where the user software did not properly clear the overflow condition.

D3D4D5

D6D7

A7 A6 A5 A4 A3 A2 A1SDA

SCL 123456789123456789123

Bus master

terminates

transfer

Bit SSPOV is set because the SSPBUF register is still full

Cleared in software

SSPBUF register is read

ACK Receiving Data

Receiving Data D0

D3D4

D6D7

ACK

R/W = 0

Receiving Address

SSPIF (PIR 1<3>)

BF (SSPSTAT<0>)

SSPOV (SSPCON<6>)

ACK

ACK is not sent

SDA

SCL

SSPIF (PIR1<3>)

BF (SSPSTAT<0>)

CKP (SSPCON<4>)

A7 A6 A5 A4 A3 A2 A1 ACK D7 D6 D5 D4 D3 D2 D1 D0 ACK

Transmitting DataR/W = 1Receiving Ad dr ess

123456789 123456789 P

Cleared in software

SSPBUF is written in software

Set bit after writing to SSPB UF

SData is

Sampled

(the SSPBUF must be written to

before the CKP bit can be set)

From SSP Interrupt

Service R out i ne

SCL held low

while CPU

responds to SSPIF

 2004 Microchip Technology Inc. DS39598E-page 79

PIC16F818/819

10.3.2 MASTER MODE OPERATION

Master mode operation is supported in firmware using

interrupt generation on the detection of the Start and

Stop conditions. The Stop (P) and Start (S) bits are

cleared from a Reset or when the SSP module is dis-

abled. The Stop (P) and Start (S) bits will toggle based

on the Start and S top conditions. Control of the I2C bus

may be taken when the P bit is set or the bus is Idle and

both the S and P bits are clear.

In Master mode operation, the SCL and SDA lines are

manipulated in firmware by clearing the corresponding

TRISB<4,1> bit(s). The output level is always low,

irrespective of the value(s) in PORTB<4,1>. So when

transmitting data, a ‘1’ data bit must have the

TRISB<1> bit set (input) and a ‘0’ data bit must have

the TRISB<1> bit cleared (output). The same scenario

is tru e for the S CL line wit h the TRISB <4> bit . Pull-up

resistors must be provided externally to the SCL and

SDA pins for proper operation of the I2C module.

The following events will cause the SSP Interrupt Flag

bit, SSPIF, to be set (SSP interrupt if enabled):

• Start condition

• Stop condition

• Data transfer byte transmitted/received

Master mode operation can be done with either the

Slave mode Idle (SSPM3:SSPM0 = 1011) or with the

Slave m ode ac tiv e. W he n bo th M as ter mode operation

and Slave modes are used, the software needs to

differentiate the source(s) of the interrupt.

For more information on Master mode operation, see

AN554, “Software Implementation of I2C™ Bus

Master” (DS00554).

10.3.3 MULTI-MASTER MODE OPERATION

In Multi-Master mode operation, the interrupt genera-

tion 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 SSP module is disabled. The Stop (P) and

Start (S) bits will toggle based on the Start and Stop

conditions. Control of the I 2C bus ma y be taken wh en

bit P (SSPSTAT<4>) is set or the bus is Idle and both

the S and P b its cl e ar. Wh en th e bu s is b us y, en a bli ng

the SSP interrupt will generate the interrupt when the

Stop condition occurs.

In Mul ti -Mast er mode o per atio n, t he SD A li ne m ust be

monitored to see if the signal level is the expected

output level. This check only needs to be done when a

high lev el is output. If a high lev el is expec ted and a low

level is present, the device needs to release the SDA

and SCL l ines (set T RISB<4, 1>). There are two st a ges

where this arbitration can be lost:

• Address Transfer

• Data Transfer

When the slave logic is enabled, the Slave device

continues to receive. If arbitration was lost during the

address transfer stage, communication to the device

may be in progr ess. If addres sed, a n ACK puls e wi ll be

generated. If arbitration was lost during the data

transfer stage, the device will need to retransfer the

data at a later time.

For more information on Multi-Master mode operation,

see AN578, “Use of the SSP Module in the I2C™

Multi-Master Environment” (DS00578).

TABLE 10-3: REGISTERS ASSOCIATED WITH I2C™ OPERATION

Addres s N a m e B it 7 Bi t 6 B it 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value o n

POR, BOR

Value on

all other

Resets

0Bh, 8Bh,

10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF ——SSPIFCCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE —— SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

13h SSPBUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu

93h SSPADD Synchronous Serial Port (I2C™ mode) Addr ess Regist er 0000 0000 0000 0000

14h SSPCON WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000

94h SSPSTAT SMP(1) CKE(1) D/A PSR/WUA BF 0000 0000 0000 0000

86h TRISB PORTB Data Direction Register 1111 1111 1111 1111

Legend: x = unknown, u = unchanged, - = unimplemented locations read as ‘0’.

Shaded cells are not used by SSP module in SPI™ mode.

Note 1: M aintain these bits clear in I2C mode.

PIC16F818/819

DS39598E-page 80  2004 Microchip Technology Inc.

NOTES:

 2003 Microchip Technology Inc. DS39598D-page 81

PIC16F818/819

11.0 ANALOG-TO-DIGITAL

CONVERTER (A/D) MODULE

The Analog-to-Digital (A/D) converter module has five

inputs for 18/20 pin devices.

The conversion of an analog input signal results in a

corresponding 10-bit digital number. The A/D module

has a high and low-voltage reference input that is

software selectable to some combination of VDD, VSS,

RA2 or RA3.

The A/D converter has a unique feature of being able

to operate while the device is in Sleep mode. To oper-

ate in Sleep, th e A/D conv ersion clock mu st be der ive d

from the A/D’s internal RC oscillator.

The A/D module has four registers:

• A/D Result High Register (ADRESH)

• A/D Result Low Register (ADRESL)

• A/D Control Register 0 (ADCON0)

• A/D Control Register 1 (ADCON1)

The ADCON0 register, shown in Register 11-1,

controls the operation of the A/D module. The

ADCON1 register, shown in Register 11-2, configures

the functions of the port pins. The port pins can be

configu red as anal og inputs (RA3 ca n also be a vol tage

reference) or as digital I/Os.

Addition al informa t ion on usi ng the A/D mo dul e c an b e

found in the “PICmicro® Mid-Range MCU Family

Refere nce M anual” (DS33023).

R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 U-0 R/W-0

ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE —ADON

bit 7 bit 0

bit 7-6 ADCS1:ADCS0: A/D Conversion Clock Sele ct bits

If ADCS2 = 0:

00 = FOSC/2

01 = FOSC/8

10 = FOSC/32

11 = FRC (clock derived from the internal A/D module RC oscillator)

If ADCS2 = 1:

00 = FOSC/4

01 = FOSC/16

10 = FOSC/64

11 = FRC (clock derived from the internal A/D module RC oscillator)

bit 5-3 CHS2:CHS0: Analog Channel Select bits

000 = Channel 0 (RA0/AN0)

001 = Channel 1 (RA1/AN1)

010 = Channel 2 (RA2/AN2)

011 = Channel 3 (RA3/AN3)

100 = Channel 4 (RA4/AN4)

bit 2 GO/DONE: A/D Conversion Status bit

If ADON = 1:

1 = A/D conversion in progress (setting this bit starts the A/D conversion)

0 = A/D conversion not in progress (this bit is automatically cleared by hardware when the

A/D conver sion is complete)

bit 1 Unimplemented: Read as ‘0’

bit 0 ADON: A/D On bit

1 = A/D converter module is operating

0 = A/D converter module is shut-off and consumes no operating current

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PIC16F818/819

DS39598D-page 82  2003 Microchip Technology Inc.

R/W-0 R/W-0 U-0 U-0 R/W-0 R/W-0 R/W-0 R/W-0

ADFM ADCS2 — — PCFG3 PCFG2 PCFG1 PCFG0

bit 7 bit 0

bit 7 ADFM: A/D Result Format Select bit

1 = Right justified, 6 Most Significant bits of ADRESH are read as ‘0’

0 = Left justified, 6 Least Significant bits of ADRESL are read as ‘0’

bit 6 ADCS2: A/D Clock Divide by 2 Select bit

1 = A/D clock source is divided by 2 when system cl ock is u sed

0 = Disabled

bit 5-4 Unimplemented: Read as ‘0’

bit 3-0 PCFG<3:0>: A/D Port Configuration Control bits

A = Analog input D = Digital I/O

C/R = Number of analog input channels/Number of A/D voltage references

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

PCFG AN4 AN3 AN2 AN1 AN0 VREF+VREF-C/R

0000 AA AAAAV

DD AVSS 5/0

0001 AVREF+ AAAAN3AVSS 4/1

0010 AA AAAAV

DD AVSS 5/0

0011 AVREF+ AAAAN3AVSS 4/1

0100 DA DAAAVDD AVSS 3/0

0101 DV

REF+ DAAAN3AVSS 2/1

011x DD DDDAVDD AVSS 0/0

1000 AVREF+ VREF- AAAN3AN23/2

1001 AA AAAAV

DD AVSS 5/0

1010 AVREF+ AAAAN3AVSS 4/1

1011 AVREF+ VREF- AAAN3AN23/2

1100 AV

REF+ VREF- AAAN3AN23/2

1101 DVREF+ VREF- AAAN3AN22/2

1110 DD DDAAVDD AVSS 1/0

1111 DV

REF+ VREF- DAAN3AN21/2

 2003 Microchip Technology Inc. DS39598D-page 83

PIC16F818/819

The ADRESH:ADRESL registers contain the result of

the A/D conversion. When the A/D conversion is

complete, the result is loaded into the A/D Result register

pair, the GO/DONE bit (ADCON0<2>) is cleared and

A/D Interrupt Flag bit, ADIF, is set. The block diagram of

the A/D module is shown in Figure 11-1.

After the A/D module has been configured as desired,

the selected channel must be acquired before the

conversion is started. The analog input channels must

have their corresponding TRIS bits selected as inputs.

To determine sample time, see Section 11.1 “A/D

Acquisition Requirements”. After this sample time

has elapsed, the A/D conversion can be started.

These steps should be followed for doing an A/D

conversion:

1. Configure the A/D module:

• Config ure ana log pins /vo lt age refer ence and

digital I/O (ADCON1)

• Select A/D input channel (ADCON0)

• Select A/D conversion cloc k (ADCO N0)

• Turn on A/D module (ADCON0)

2. Configure A/D interrupt (if desired):

• Clear ADIF bit

• Set ADIE bit

• Set GIE bit

3. Wait the required acquisition time.

4. Start conversion:

• Set GO/DONE bit (ADCON0)

5. Wait for A/D conversion to complete by either:

• Polling for the GO/DONE bit to be cleared

(with interrupts disabled); OR

• Waiting for the A/D interrupt

6. Read A/D Result register pair

(ADRESH:ADRESL), clear bit ADIF if required.

7. For next conversion, go to step 1 or step 2 as

required. The A/D conversion time per bit is

defined as TAD. A minimum wait of 2 TAD is

required before the next acquisition starts.

FIGURE 11-1: A/D BLOCK DIAGRAM

(Input Voltage)

VIN

VREF+

(Reference

Voltage)

AVDD

PCFG<3:0>

CHS<3:0>

RA3/AN3/VREF+

RA2/AN2/VREF-

RA1/AN1

RA0/AN0

011

010

001

000

A/D

Converter

VREF-

(Reference

Voltage) AVSS

PCFG<3:0>

RA4/AN4/T0CKI

100

PIC16F818/819

DS39598D-page 84  2003 Microchip Technology Inc.

11.1 A/D Acquisition Requirements

For the A/D converter 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 1 1-2. Th e source

impeda nce (RS) and the inte rnal sam pling swi tch (RSS)

impedance directly affect the time required to charge

the capacitor CHOLD. The sampling switch (RSS)

impedance varies over the device voltage (VDD), see

Figure 11-2. The maximum recommended imped-

ance for analog sou rces is 2.5 k Ω. As the imped ance

is decreased, the acquisition time may be decreased.

After the analog input channel is selected (changed),

this acquisition must be done before the conversion

can be sta r ted .

To calculate the minimum acquisition time,

Equation 11-1 may be used. This equation assumes

that 1/2 LSb error is used (1024 st eps for the A/D). The

1/2 LSb er ror is the ma ximu m error allow ed for the A/D

to meet its specified resolution.

To calculate the minimum acquisition time, TACQ, see

the “PICmicro® Mid-Range MCU Family Reference

Manual” (DS33023).

EQUATION 11-1: ACQUISITION TIME

FIGURE 11-2: ANALOG INPUT MODEL

TACQ

Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient

TAMP + TC + TCOFF

2 µs + TC + [(Temperature – 25°C)(0.05 µs/°C)]

CHOLD (RIC + RSS + RS) In(1/2047)

-120 pF (1 kΩ + 7 kΩ + 10 kΩ) In(0.0004885)

16.47 µs

2 µs + 16.47 µs + [(50°C – 25°C)(0.05 µs/°C)

19.72 µs

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 kΩ. This is required to meet the pin

leakage specification.

4: After a conversion has completed, a 2.0 TAD delay must complete before acquisition can begin again.

During this time, the holding capacitor is not connected to the selected A/D input channel.

CPIN

RSANx

5 pF

VDD

VT = 0.6V

VT = 0.6V ILEAKAGE

RIC ≤ 1K

Sampling

Switch

SS RSS

CHOLD

= DAC Capacitance

VSS

Sampling Switch

567891011

(kΩ)

VDD

= 120 pF

± 500 nA

Legend: CPIN

ILEAKAGE

RIC

CHOLD

= input capacitance

= threshold voltage

= leakage current at the pin due to

= interconnect resistance

= sampling switch

= sample/hold capacitance (from DAC)

various junctions

 2003 Microchip Technology Inc. DS39598D-page 85

PIC16F818/819

11.2 Selecting the A/D Conversion

Clock

The A/D conversion time per bit is defined as TAD. The

A/D conversion requires 9.0 TAD per 10-bi t conv ers io n.

The source of the A/D conversion clock is software

selectable. The seven possible options for TAD are:

•2T

OSC

•4TOSC

•8TOSC

•16TOSC

•32TOSC

•64TOSC

• Internal A/D module RC osc il lat or (2-6 µs)

For correct A/D conversions, the A/D conversion clock

(TAD) must be selected to ensure a minimum TAD time

as small as possible, but no less than 1.6 µs and not

greater than 6.4 µs.

Table 11-1 shows the resultant TAD times de rive d from

the device operating frequencies and the A/D clock

sour ce se lec ted .

11.3 Configuring Anal og Port Pins

The ADCON1 and TRISA registers control the opera-

tion of the A/D port pins. The port pins that are desired

as analog inputs must have their corresponding TRIS

bits set (input). If the TRIS bit is cleared (output), the

digital output level (VOH or VOL) will be converted.

The A/D operation is independent of the state of the

CHS<2:0> bits and the TRIS bits .

TABLE 11-1: TAD vs. MAXIMUM DEVICE OPERATING FREQUENCIES (ST ANDARD DEVICES (F))

Note 1: When reading the Port register, all pins

configured as analog input channels will

read as c lea red (a lo w l evel). Pins co nfi g-

ured as digital inputs will convert an

analog input. Analog levels on a digitally

configured input will not affect the

conversion accuracy.

2: Analog le vels on any pin that is defined as

a digital input (including the AN4:AN0

pins) may cause the input buffer to

consume current out of the device

specification.

AD Clock Source (TAD)Maximum Device F requency

Operation ADCS<2> ADCS<1:0>

2 TOSC 0001.25 MHz

4 TOSC 1002.5 MHz

8 TOSC 001 5 MHz

16 TOSC 101 10 MHz

32 TOSC 010 20 MHz

64 TOSC 110 20 MHz

RC(1,2,3) X11(Note 1)

Note 1: The RC source has a typical TAD time of 4 µs but can vary between 2-6 µs.

2: When the device frequencies are greater than 1 MHz, the RC A/D conversion clock source is only

recommended for Sleep operation.

3: For extended voltage devices (LF), please refer to Section 15.0 “Electrical Characteristics”.

PIC16F818/819

DS39598D-page 86  2003 Microchip Technology Inc.

11.4 A/D Conversions

Clearing the GO/DONE bit during a conversion will

abort the current conversion. The A/D Result register

pair will NOT be upda ted wi th th e partial ly comp leted

A/D conversion sample . That is, the ADRESH:ADRESL

registers will continue to contain the value of the last

completed conversion (or the last value written to the

ADRESH:ADRESL registers). After the A/D conversion

is aborted, a 2-TAD wait is required before the next

acquisition is started. After this 2-TAD wait, acquisition

on the selected channel is automatically started. The

GO/DONE bit can then be set to start the conversion.

In Figure 11-3, after the GO bit is set, the first time

segment has a minimum of T CY and a maximum of T AD.

11.4.1 A/D RESULT REGISTERS

The ADRESH:ADRESL register pair is the location

where the 10-bit A/D result is loaded at the completion

of the A/D co nversion . This register p air is 16 bit s wide.

The A/D mo dule gives the flexib ility to left or righ t justify

the 10-bit result in the 16-bit result register. The A/D

Format Select bit (ADFM) controls this justification.

Figure 11-4 shows the operation of the A/D result

justification. The extra bits are loaded with ‘0’s. W he n

an A/D result will not overwrite these locations (A/D

disable), these registers may be used as two general

purpose 8-bit registers.

FIGURE 11-3: A/D CONVERSION TAD CYCLES

FIGURE 11-4: A/D RESULT JUSTIFICATION

Note: The GO/DONE bit should NOT be set in

the same instruction that turns on the A/D.

TAD1TAD2 TAD3 TAD4 TAD5 TAD6

7 T

TAD9

Set GO bit

Holding Capacitor is disconnected from analog input (typically 100 ns)

b9 b8 b7 b6 b5 b4 b3 b2

TAD10 TAD11

b1 b0

TCY to TAD

Conversion starts

ADRES is loaded,

GO bit is cleared,

ADIF bit is set,

Holding Capacitor is connected to analog input

10-bit Result

ADRESH ADRESL

0000 00

ADFM = 0

2 1 0 77

10-bit Result

ADRESH ADRESL

10-bit Result

0000 00

70 7 6 5 0

ADFM = 1

Right Justified Left Justified

 2003 Microchip Technology Inc. DS39598D-page 87

PIC16F818/819

11.5 A/D Operation During Sleep

The A/D module can operate during Sleep mode. This

requires that the A/D clock source be set to RC

(ADCS1:ADCS0 = 11). When the RC clock source is

selected, the A/D module waits one instruction cycle

before starting the conversion. This allows the SLEEP

instruction to be executed which eliminates all digital

switchi ng noise fro m the conv ersion. Whe n the conver-

sion i s comple ted, the GO /DONE bit will be cleared and

the result loaded into the ADRES register. If the A/D

interrupt is enabled, the device will wake-up from

Sleep. If the A/D interrupt is not enabled, the A/D

modul e wil l then be t urned off, alt hough the A DON bi t

will remain set.

When the A/D clock sour ce is anoth er clock optio n (not

RC), a SLEEP instruction will ca use the present conver-

sion t o be aborte d and the A/D mod ule to be turned of f,

though the ADON bit will remain set.

Turnin g off the A/D places the A/D m odu le in its low est

current consumption state.

11.6 Effects of a Reset

A device Reset forces all registers to their Reset state.

The A/D module is disabled and any conversion in

progress is aborted. All A/D input pins are configured

as analog inputs.

The value that is in the ADRESH:ADRESL registers

is not modified for a Power-on Reset. The

ADRESH:ADRESL registers w ill cont ain unkno wn data

after a Power-on Reset.

11.7 Use of the CCP Trigger

An A/D convers ion can be st arted by th e “special event

trigger” of the CCP module. This requires that the

CCP1M3:CCP1M0 bits (CCP1CON<3:0>) be

programmed as ‘1011’ and that the A/D module is

enabled (ADON bit is set). When the trigger occurs, th e

GO/DONE bit will be set, starting the A/D conversion

and the Timer1 counter will be reset to zero. Timer1 is

reset to autom atical ly rep eat th e A/D ac quisitio n perio d

with minimal software overhead (moving the

ADRESH:ADRESL to the de sired loc ation). The appro-

priate analog input channel must be selected and the

minimum acquisition done before the “special event

trigger” sets the GO/DONE bit (starts a conversion).

If the A/D module is not enabled (ADON is cleared),

then the “special event trigger” will be ignored by the

A/D module but will still reset the Timer1 counter.

TABLE 11-2: REGISTERS/BITS ASSOCIATED WITH A/D

Note: For the A/D module to operate in Sleep,

the A/D clock source must be set to RC

(ADCS1:ADCS0 = 11). To perform an A/D

conversion in Sleep, ensure the SLEEP

instruction immediately follows the

instruction that sets the GO/DONE bit.

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

0Bh,8Bh

10Bh,18Bh INTCON GIE PEIE TMR0IE INTE RBIE TMR0IF INTF RBIF 0000 000x 0000 000u

0Ch PIR1 —ADIF— — SSPIF CCP1IF TMR2IF TMR1IF -0-- 0000 -0-- 0000

8Ch PIE1 —ADIE— — SSPIE CCP1IE TMR2IE TMR1IE -0-- 0000 -0-- 0000

1Eh ADRESH A/D Result Register High Byte xxxx xxxx uuuu uuuu

9Eh ADRESL A/D Result Register Low Byte xxxx xxxx uuuu uuuu

1Fh ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE —ADON0000 00-0 0000 00-0

9Fh ADCON1 ADFM ADCS2 —— PCFG3 PCFG2 PCFG1 PCFG0 00-- 0000 00-- 0000

05h PORTA RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0 xxx0 0000 uuu0 0000

85h TRISA TRISA7 TRISA6 TRISA5 PORTA Data Direction Register 1111 1111 1111 1111

Legend: x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used for A/D conversion.

PIC16F818/819

DS39598D-page 88  2003 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 89

PIC16F818/819

12.0 SPECIAL FEATURES OF

THE CPU

These devices have a host of features intended to

maximize sys tem reliability, minimize cost through elimi-

nation of external components, provide power-saving

operating modes and offer code pro tection:

• Reset

- Power-on Reset (POR)

- Power-up Timer (PWRT)

- Oscillator Start-up Timer (OST)

- Brown-out Reset (BOR)

• Interrupts

• Watchdog Timer (WDT)

• Sleep

• Code Protection

• ID Locations

• In-Circuit Serial Programming

There are two timers that offer necessary delays on

power-up. One is the Oscillator Start-up Timer (OST),

intende d to keep the chip in Reset until the crystal oscil-

lator is st able. The other is the Power-up T imer (PWRT)

which provides a fixed delay of 72 ms (nominal) on

power-up only. It is designed to keep the part in Reset

while the power supply stabilizes and is enabled or

disabled using a configuration bit. With these two

timers on-chip, most applications need no external

Reset circuitry.

Sleep mode is designed to offer a very low-current

power-down mode. The user can wake-up from Sleep

through external Reset, Watchdog Timer wake-up or

through an interrupt.

Several oscillator options are also made available to

allow the part to fit the application. The RC oscillator

option saves system cost while the LP crystal option

saves power. Configuration bits are used to select the

desired oscillator mode.

Additional information on special features is available

in the “PICmicro® Mid-Range MCU Family Reference

Manual” (DS33023).

12.1 Configuration Bits

The configuration bits can be programmed (read as

‘0’), or left unprogrammed (read as ‘1’), to select

various devi ce configurations. These bits are mapped

in program memory location 2007h.

The user will note that address 2007h is beyond the

user program memory space which can be accessed

only during programming.

PIC16F818/819

DS39598E-page 90  2004 Microchip Technology Inc.

R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1 R/P-1

CP CCPMX DEBUG WRT1 WRT0 CPD LVP BOREN MCLRE FOSC2 PWRTEN WDTEN FOSC1 FOSC0

bit 13 bit 0

bit 13 CP: Flas h Program M emory Co de Prote ction bi t

1 = C o de p rotecti on off

0 = All memory locations code-protected

bit 12 CCPMX: CCP1 Pi n Selec ti on bi t

1 = CCP1 function on RB2

0 = CCP1 function on RB3

bit 11 DEBUG: In-Circuit Debugger Mode bit

1 = In-Ci rc ui t Debugg er disa bled, R B6 and R B7 are ge ne ral p urp os e I/O p in s

0 = In-Ci rc ui t Debugg er enabled, R B6 and R B7 are de dicate d to the deb ug ge r

bit 10-9 WRT1:WRT0: Fla sh Prog ram M e mo ry Write Enabl e b its

For PIC16F818:

11 = Write p rot ec ti on off

10 = 000h to 01FF w ri te- pro t e ct ed, 0 20 0 t o 0 3F F m a y be m od ifi ed b y EEC ON con t ro l

01 = 000h to 03 FF w ri te-prote ct ed

For PIC16F819:

11 = Write p rot ec ti on off

10 = 0000 h to 0 1F F h wri te-protected, 0 20 0h to 07 FFh ma y be m odi fi ed by EECO N c on trol

01 = 0000 h to 0 3F F h wri te-protected, 0 40 0h to 07 FFh ma y be m odi fi ed by EECO N c on trol

00 = 0000 h to 0 5F F h wri te-protected, 0 60 0h to 07 FFh ma y be m odi fi ed by EECO N c on trol

bit 8 CPD: Data EE Memory Code Protection bit

1 = C o de p rotecti on off

0 = Data EE memory locations code-protected

bit 7 LVP: Low- Volt age Prog ramm ing Ena ble bit

1 = RB3/PGM pin has PGM function, Low-Voltage Programming enabled

0 = RB3/PGM pin has digital I/O function, HV on MCLR must be used for programming

bit 6 BOREN: Brown-out Reset Enable bit

1 = BOR en ab le d

0 = BOR di sa bl ed

bit 5 MCLRE: RA5/MCLR/VPP Pin Fu nc ti on Se le ct bit

1 = RA5/MCL R/VPP pin func tion is MCLR

0 = RA5/MCL R/VPP pin fun ctio n is dig ita l I/O, MC LR internally tied to VDD

bit 3 PWRTEN: Power- up Timer Enab le bi t

1 = PWRT disabled

0 = PWRT enabled

bit 2 WDTEN: W atchdog Timer Enable bit

1 = WDT en abled

0 = WDT di sabl ed

bit 4, 1-0 FOSC2:FOSC0: Oscillator Selection bits

111 = EXTRC osc il lator ; CL KO fu nc tion o n RA 6/O SC2 /CL KO p in

110 = EXTRC osc il la tor ; p ort I/ O fu nctio n on RA6 /O SC2 /CLK O pi n

101 = INTRC os c illa tor; CL KO fu nc ti on o n R A 6/O SC 2 /CL KO p in an d po rt I/O fu nc ti on o n

RA7/O SC 1/ CLKI pin

100 = INTR C os c il la tor ; port I/O fu nc ti on on b oth R A6 /O S C2 /C LK O pi n and R A 7/O SC 1 /CL K I p in

011 = EXTCLK; po rt I/O f un ct ion o n RA6/ OS C2/CL KO p in

010 = HS oscillator

001 = XT os ci ll ator

000 = LP oscillator

Note 1: The erased (unprogrammed) value of the Configuration Word is 3FFFh.

Legend:

R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘1’

-n = Value when device is unprogrammed u = Unchanged from programmed state

 2004 Microchip Technology Inc. DS39598E-page 91

PIC16F818/819

12.2 Reset

The PIC16F818/819 differentiates between various

kinds of Re set :

• Power-on Reset (POR )

•MCLR

Reset during normal operation

•MCLR

Reset du ring Sleep

• WDT Reset during normal operation

• WDT wake-up during Sleep

• Brown-out Reset (BOR)

Some regi sters a re not af fected in a ny Rese t conditio n.

Their statu s is unk nown o n POR an d unchan ged in any

other Reset. Most other registers are reset to a “Reset

state” on Power-on Reset (POR), on the MCLR and

WDT Rese t, on MCL R Rese t du ring Sle e p and Brow n-

out Reset (BOR). They are not affected by a WDT

wake-up which is viewed as the resumption of normal

operation. The TO and PD bits are set or cleared

differently in different Reset situations as indicated in

Table 12-3. These bits are used in software to

determine the nature of the Reset. Upon a POR, BOR

or wake-up from Sleep, the CPU requires

approximately 5-10 µs to become ready for code

execution. This delay runs in parallel with any other

timers. See Table 12-4 for a full description of Reset

state s of all regi sters.

A simp lified block di agram o f the on -chip R eset cir cuit

is sh own in Figure 12-1 .

FIGURE 12-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

External

Reset

MCLR

VDD

OSC1

WDT

Module

VDD Rise

Detect

OST/PWRT

INTRC

WDT

Time-out

Power-on Reset

OST

10-bit Ripple Counter

PWRT

Chip_Reset

10-bit Ripple Counter

Reset

Enable OST

Enable PWRT

Sleep

Brown-out

Reset BOREN

31.25 kHz

PIC16F818/819

DS39598E-page 92  2004 Microchip Technology Inc.

12.3 MCLR

PIC16F818/819 device has a noise filter in the MCLR

Reset path. The filter will detect and ignore small

pulses.

It should be noted that a WDT Reset does not drive

MCLR pin low.

The behavior of the ESD protection on the MCLR pin

has been altered from previous devices of this family.

Voltages appli ed to the pin th at exce ed it s spe cific ation

can resul t in both MCLR an d excess ive current be yond

the device specification during the ESD event. For this

reason, Microchip recommends that the MCLR pin no

longer be tied directly to VDD. The use of an

RC network, as shown in Figure 12-2, is suggested.

The RA5/MCLR/VPP pin can be configured for MCLR

(default) or as an I/O pin (RA5). This is configured

through the MCLRE bit in the Configuration Word

FIGURE 12-2: RECOMMENDED MCLR

CIRCUIT

12.4 Power-on Reset (POR)

A Power-on Reset pulse is generated on-chip when

VDD rise is detected (in the range of 1.2V -1.7V). To take

advantage of the POR, tie the MCLR pin to VDD as

described in Section 12.3 “MCLR”. A maximum rise

time fo r VDD is specif ied. See Section 15.0 “Electric al

Characteristics” for details.

When the device starts normal operation (exits the

Reset condition), device operating parameters (volt-

age, fr equency, temp erature, ...) mus t be met to ensu re

operation. If these conditions are not met, the device

must be held in Reset until the operating conditions are

met. For more information, see Application Note

AN607, “Power-up Tr oub le Shoo tin g” (DS00607).

12.5 Power-up Timer (PWRT)

The Power-up Timer (PWRT) of the PIC16F818/819 is

a counter that uses the INTRC oscillator as the clock

input. This yields a count of 72 ms. While the PWRT is

counting, the device is held in Reset.

The power-up time delay depends on the INTRC and

will vary from chip-to-chip due to temperature and

process variation. See DC parameter #33 for details.

The PWRT is enabled by clearing configuration bit,

PWRTEN.

12.6 Oscillator Start-up Timer (OST)

The Oscillator Start-up Timer (OST) provides 1024

oscillator cycles (from OSC1 input) delay after the

PWRT delay is over (if enabled). This helps to ensure

that the crystal oscillator or resonator has started and

stabilized.

The OST time-out is invoked only for XT, LP and HS

modes and only on Power-on Reset or wake-up from

Sleep.

12.7 Brown-out Reset (BOR)

The configuration bit, BOREN, can enable or disable

the Brown-out Reset circuit. If VDD falls below VBOR

(parameter #D005, about 4V) for longer than TBOR

(param eter #3 5, abou t 100 µs), the brown-ou t situatio n

will reset the device. If VDD falls below VBOR for less

than TBOR, a Reset may not occur.

Once the brown-out occurs, the device will remain in

Brown-out Reset until VDD rises above VBOR. The

Power-up Timer (if enabled) will keep the device in

Rese t fo r TPWRT (parameter #33, about 72 ms). If VDD

should fall below VBOR during TPWRT, the Brown-out

Reset process will restart when VDD rises above VBOR

with the Power-up Timer Reset. Unlike previous PIC16

devices, the PWRT is no longer automatically enabled

when the Brown-out Reset circuit is enabled. The

PWRTEN and BOREN configuration bits are

independent of each other.

12.8 Time-out Sequence

On power-up, the time-out sequence is as follows: the

PWRT delay starts (if enabled) when a POR occurs.

Then, OST starts coun tin g 102 4 os ci ll ator cycle s whe n

PWRT ends (LP, XT, HS). When the OST ends, the

device comes out of Reset.

If MCLR is kept low long enough, all delays will expire.

Bringing MCLR high will begin execution immediately.

This is useful for testing purposes or to synchronize

more than one PIC16F818/819 device operating in

parallel.

Table 12-3 shows the Reset conditions for the Status,

PCON and PC registers, while Table 12-4 shows the

Reset con ditions for all the r egisters.

0.1 µF

1 kΩ (or greater)

(optional, not critical)

VDD

MCLR

PIC16F818/819

 2004 Microchip Technology Inc. DS39598E-page 93

PIC16F818/819

12.9 Power Control/Status Register

(PCON)

The Power C ontrol/Statu s register, PCON, has two bits

to indicate the type of Reset that last occurred.

Bit 0 is Brown-out Reset Status bit, BOR. Bit BOR is

unknown on a Power-on Reset. It must then be set by

the user and checked on subsequent Resets to see if

bit BOR cleared, indicating a Brown-out Reset

occurred. When the Brown-out Reset is disabled, the

state of the BOR bit is unpredictable.

Bit 1 is Pow er-on Reset S tatus bit, POR. It is cleared on

a Power-on Reset and unaffected otherwise. The user

must set this bit following a Power-on Reset.

TABLE 12-1: TIME-OUT IN VARIOUS SITUATIONS

TABLE 12-2: STATUS BITS AND THEIR SIGNIFICANCE

TABLE 12-3: RESET CONDITION FOR SPECIAL REGISTERS

Oscillator

Configuration Power-up Brown-out Reset Wake-up

from Sleep

PWRTE = 0PWRTE = 1PWRTE = 0PWRTE = 1

XT, HS, LP TPWRT + 1024 • TOSC 1024 • TOSC TPWRT + 1024 • TOSC 1024 • TOSC 1024 • TOSC

EXTRC, EXTCLK, INTRC TPWRT 5-10 µs(1) TPWRT 5-10 µs(1) 5-10 µs(1)

Note 1: CPU start-up is always invoked on POR, BOR and wake-up from Sleep.

POR BOR TO PD

0x11Power-on Reset

0x0xIllegal, TO is set on POR

0xx0Illegal, PD is set on POR

1011Brown-out Reset

1101WDT Reset

1100WDT wake-up

11uuMCLR Reset during normal operation

1110MCLR Reset during Sleep or interrupt wake-up from Sleep

Legend: u = unchanged, x = unknown

Condition Program

Counter Status

Power-on Reset 000h 0001 1xxx ---- --0x

MCLR Reset during normal operation 000h 000u uuuu ---- --uu

MCLR Reset during Sleep 000h 0001 0uuu ---- --uu

WDT Reset 000h 0000 1uuu ---- --uu

WDT wake-up PC + 1 uuu0 0uuu ---- --uu

Brown-out Reset 000h 0001 1uuu ---- --u0

Interrupt wake-up from Sleep PC + 1(1) uuu1 0uuu ---- --uu

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’

Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector

(0004h).

PIC16F818/819

DS39598E-page 94  2004 Microchip Technology Inc.

TABLE 12-4: INITIALIZATION CONDITIONS FOR ALL REGISTERS

Brown-out Reset MCLR Reset,

WDT Reset Wake-up via WDT or

Interrupt

Wxxxx xxxx uuuu uuuu uuuu uuuu

INDF N/A N/A N/A

TMR0 xxxx xxxx uuuu uuuu uuuu uuuu

PCL 0000h 0000h PC + 1(2)

STATUS 0001 1xxx 000q quuu(3) uuuq quuu(3)

FSR xxxx xxxx uuuu uuuu uuuu uuuu

PORTA xxx0 0000 uuu0 0000 uuuu uuuu

PORTB xxxx xxxx uuuu uuuu uuuu uuuu

PCLATH ---0 0000 ---0 0000 ---u uuuu

INTCON 0000 000x 0000 000u uuuu uuuu(1)

PIR1 -0-- 0000 -0-- 0000 -u-- uuuu(1)

PIR2 ---0 ---- ---0 ---- ---u ----(1)

TMR1L xxxx xxxx uuuu uuuu uuuu uuuu

TMR1H xxxx xxxx uuuu uuuu uuuu uuuu

T1CON --00 0000 --uu uuuu --uu uuuu

TMR2 0000 0000 0000 0000 uuuu uuuu

T2CON -000 0000 -000 0000 -uuu uuuu

SSPBUF xxxx xxxx uuuu uuuu uuuu uuuu

SSPCON 0000 0000 0000 0000 uuuu uuuu

CCPR1L xxxx xxxx uuuu uuuu uuuu uuuu

CCPR1H xxxx xxxx uuuu uuuu uuuu uuuu

CCP1CON --00 0000 --00 0000 --uu uuuu

ADRESH xxxx xxxx uuuu uuuu uuuu uuuu

ADCON0 0000 00-0 0000 00-0 uuuu uu-u

OPTION_REG 1111 1111 1111 1111 uuuu uuuu

TRISA 1111 1111 1111 1111 uuuu uuuu

TRISB 1111 1111 1111 1111 uuuu uuuu

PIE1 -0-- 0000 -0-- 0000 -u-- uuuu

PIE2 ---0 ---- ---0 ---- ---u ----

PCON ---- --qq ---- --uu ---- --uu

OSCCON -000 -0-- -000 -0-- -uuu -u--

OSCTUNE --00 0000 --00 0000 --uu uuuu

PR2 1111 1111 1111 1111 1111 1111

SSPADD 0000 0000 0000 0000 uuuu uuuu

SSPSTAT 0000 0000 0000 0000 uuuu uuuu

ADRESL xxxx xxxx uuuu uuuu uuuu uuuu

ADCON1 00-- 0000 00-- 0000 uu-- uuuu

EEDATA xxxx xxxx uuuu uuuu uuuu uuuu

EEADR xxxx xxxx uuuu uuuu uuuu uuuu

EEDATH --xx xxxx --uu uuuu --uu uuuu

EEADRH ---- -xxx ---- -uuu ---- -uuu

EECON1 x--x x000 u--x u000 u--u uuuu

EECON2 ---- ---- ---- ---- ---- ----

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition,

r = reserved, main tain clear

Note 1: One or more bits in INTCON, PIR1 and PR2 will be affected (to cause wake-up).

2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).

3: See Table 12-3 for Reset value for specific conditions.

 2004 Microchip Technology Inc. DS39598E-page 95

PIC16F818/819

FIGURE 12-3: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD THROUGH

PULL-UP RESISTOR)

FIGURE 12-4: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD THROUGH

RC NETWORK): CASE 1

FIGURE 12-5: TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD THROUGH

RC NETWORK): CASE 2

TPWRT

TOST

VDD

MCLR

Internal POR

PWRT Time-out

OST Time-out

Internal Reset

TPWRT

TOST

VDD

MCLR

Internal POR

PWRT Time-out

OST Time-out

Internal Reset

VDD

MCLR

Internal POR

PWRT Time-out

OST Time-out

Internal Reset

TPWRT

TOST

PIC16F818/819

DS39598E-page 96  2004 Microchip Technology Inc.

FIGURE 12-6: SLOW RISE TIME (MCLR TIED TO VDD THROUGH RC NETWORK)

12.10 Interrupts

The PIC16F818/819 has up to nine sources of inter-

rupt. The Interrupt Control register (INTCON) records

individual interrupt requests in flag bits. It also has

individual and global interrupt enable bits.

A Global Interrupt Enable bit, GIE (INTCON<7>),

enables (if set) all unmasked interrupts or disables (if

cleared) all interrupts. When bit GIE is enabled and an

inter rupt’s flag bit and mask bi t are s et, the int errupt will

vector immediately. Individual interrupts can be

disabled through their corresponding enable bits in

various registers. Individual interrupt bits are set

regardless of the status of the GIE bit. The GIE bit is

cleared on Reset.

The “return from interrupt” instruction, RETFIE, exits

the interrupt routine, as well as sets the GIE bit, which

re-enabl es inte rrupts.

The RB0/INT pin interrupt, the RB port change interrupt

and the TMR 0 over flo w interru pt f lag s are co nt a ine d in

the INTCON register.

The peripheral interrupt flags are contained in the

Special Function Register, PIR1. The corresponding

interrupt enable bits are contained in Special Function

contained in Special Function Register, INTCON.

When an interrupt is serviced, the GIE bit is cleared to

disable any further interrupt, the return address is

pushed onto the stack a nd the PC is loa ded with 0004h.

Once in the Interrupt Service Routine, the source(s) of

the interrupt can be determined by polling the interrupt

flag bits. The interrupt flag bit(s) must be cleared in

software before re-enabling interrupts to avoid

recursiv e inte rrup t s.

For external interrupt events, such as the INT pin or

PORTB change interrupt, the interrupt latency will be

three or four instruction cycles. The exact latency

depends on when the interrupt event occurs relative to

the current Q cycle. The latency is the same for one or

two-cycle instructions. Individual interrupt flag bits are

set regardless of the status of their corresponding

mask bit, PEIE bit or the GIE bit.

FIGURE 12-7: INTERRUPT LOGIC

VDD

MCLR

Internal POR

PWRT Time-out

OST Time-out

Internal Reset

0V 1V

TPWRT

TOST

Note: Individual interrupt flag bits are set

regardless of the status of their

corresponding mask bit or the GIE bit.

ADIF

ADIE

SSPIF

SSPIE

CCP1IF

CCP1IE

TMR2IF

TMR2IE

TMR1IF

TMR1IE

TMR0IF

TMR0IE

INTF

INTE

RBIF

RBIE

GIE

PEIE

Wake-up (if in Sleep mode)

Interrupt to CPU

EEIF

EEIE

 2004 Microchip Technology Inc. DS39598E-page 97

PIC16F818/819

12.10.1 INT INTERRUPT

External in terrupt on the RB0/INT pin is edge trigg ered,

either rising if bit INTEDG (OPTION_REG<6>) is set,

or falling if the INTEDG bit is clear. When a valid edge

appears on the RB0/INT pin, flag bit, INTF

(INTCON<1 >), i s s et. T his in terru pt c an b e d isa bl ed b y

clear ing en abl e bi t, I NTE (IN TCON <4 >). Fla g bi t IN TF

must be cleared in software in the Interrupt Service

Routin e before re-enablin g this interrupt. The INT int er-

rupt can wake-up the processor from Sleep if bit INTE

was set prior to going into Sleep. The status of Global

Interrupt Enable bit, GIE, decides whether or not the

processor branches to the interrupt vector following

wake-up. See Section 12.13 “Power-Down Mode

(Sleep)” for details on Sleep mode.

12.10.2 TMR0 INTERRUPT

An overflow (FFh → 00h) in the TMR0 register will set

flag bit, TMR0IF (INTCON<2>). The interrupt can be

enabled/disabled by setting/clearing enable bit,

TMR0IE (INTCON<5>) (see Section 6.0 “Timer0

Module”).

12.10.3 PORTB INTCON CHANGE

An input change on PORTB<7:4> sets flag bit, RBIF

(INTCON<0>). The interrupt can be enabled/disabled

by setting/clearing enabl e bit, RBIE (INTCON<3>). See

Section 3.2 “EECON1 and EECON 2 Registers” .

12.11 Context Saving During Interrupts

During an interrupt, only the return PC value is saved

on the stack. Typically, users may wish to save key

registers during an interrupt (i.e., W, Status registers).

This wi ll hav e to be implement ed i n software as sho wn

in Example 12-1.

For PIC16F818 devices, the upper 64 bytes of each

bank are common. Temporary holding registers,

W_TEMP and STATUS_TEMP, should be p laced her e.

These 64 locations do not require banking and

therefore, make it easier for context save and restore.

For PIC16F819 devices, the upper 16 bytes of each

bank are common.

EXAMPLE 12-1: S AVING STATUS AND W REGISTERS IN RAM

MOVWF W_TEMP ;Copy W to TEMP register

SWAPF STATUS, W ;Swap status to be saved into W

CLRF STATUS ;bank 0, regardless of current bank, Clears IRP,RP1,RP0

MOVWF STATUS_TEMP ;Save status to bank zero STATUS_TEMP register

:(ISR) ;Insert user code here

SWAPF STATUS_TEMP, W ;Swap STATUS_TEMP register into W

;(sets bank to original state)

MOVWF STATUS ;Move W into STATUS register

SWAPF W_TEMP, F ;Swap W_TEMP

SWAPF W_TEMP, W ;Swap W_TEMP into W

PIC16F818/819

DS39598E-page 98  2004 Microchip Technology Inc.

12.12 Watchdog Timer (WDT)

For PIC16F818/819 devices, the WDT is driven by the

INTRC oscillator. When the WDT is enabled, the

INTRC (31.25 kHz) oscillator is enabled. The nominal

WDT period is 16 ms and has the same accuracy as

the INTRC oscillator.

During n ormal operati on, a WDT ti me-out genera tes a

device Reset (Watch dog Time r Reset). If the device is

in Sleep mode, a WDT time-out causes the device to

wake-up and continue with normal operation (Watchdog

T imer wake-up). The TO bit in t he S t at us re gist er wil l be

cleared upon a Watchdog Timer time-out.

The WDT can be permanent ly disabled by clear ing con-

figuration bit, WDTEN (see Section 12.1 “Configuration

Bits”).

WDT time-out period values may be found in

Section 15.0 “Electrical Characteristics” under

param ete r #31 . Values for the WDT p resc al er (ac tua ll y

a posts caler but shared with the T imer0 pres caler) may

be assigned using the OPTION_REG register.

FIGURE 12-8: WATCHDOG TIMER BLOCK DIAGRAM

TABLE 12-5: SUMMARY OF WATCHDOG TIMER REGISTERS

Note 1: The CLRWDT and SLEEP instructions

clear the WDT and the postscaler if

assigned to the WDT and prevent it from

timing out and generating a devic e R es et

condition.

2: When a CLRWDT instruction is executed

and the pre scaler is assi gned to the WDT,

the pr escaler co unt will be cle ared but th e

presc al er ass ig nme nt is not changed.

From TMR0 Clock Source

(Figure 6-1)

To TMR0 (Figure 6-1)

Postscaler

INTRC

WDT

Enable Bit

PSA

8-to-1 MUX PS2:PS0

MUX PSA

WDT

Time-out

Note: PSA and PS2:PS0 are bits in the OPTION_REG register.

31.25 kHz

Address Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0

81h,181h OPTION_REG RBPU INTEDG T0CS T0SE PSA PS2 PS1 PS0

2007h Configuration bits(1) LVP BOREN MCLRE FOSC2 PWRTEN WDTEN FOSC1 FOSC0

Legend: Shaded cells are not used by the Watchdog Timer.

Note 1: See Register 12-1 for operation of these bits.

 2004 Microchip Technology Inc. DS39598E-page 99

PIC16F818/819

12.13 Power-Down Mode (Sleep)

Power-Down mode is entered by executing a SLEEP

instruction.

If enabled, the Watchdog Timer will be cleared but

keeps running, the PD bit (Status<3>) is cleared, the

TO (Status<4>) bit is set and the oscillator driver is

turned off. The I/O ports maintain the status they had

before the SLEEP instruction was executed (driving

high, low or high-i mpedance).

For lo west curr ent con sum pti on in this mo de, plac e all

I/O pins at either VDD or VSS, ensure no external cir-

cuitr y is dr awing cu rrent from th e I/O pi n, powe r-dow n

the A/D and disable external clocks. Pull all I/O pins

that are high-impedance inputs, high or low externally,

to avoid switching currents caused by floating inputs.

The T0CKI input should also be at VDD or VSS for

lowest current consumption. The contribution from

on-chip pull-u ps on POR TB should also be consid ered.

The MCLR pin must be at a logic high level (VIHMC).

12.13.1 WAKE-UP FROM SLEEP

The devi ce can wake -up from Sleep through one of th e

following events:

1. External Reset input on MCLR pin.

2. Watchdog Timer wake-up (if WDT was

enabled).

3. Interrupt from INT pin, RB port change or a

peripheral interrupt.

External MCLR Reset will cause a device Reset. All

other events are considered a continuation of program

execut ion and c aus e a “wak e-u p”. The TO and PD bits

in the Status register can be used to determine the

cause of the device Reset. The PD bit, w h ic h i s se t on

power-up, is cleared when Sleep is invoked. The TO bit

is cleared if a WDT time-out occurred and caused

wake-up.

The follo wing periph eral interrupt s can wake the device

from Sleep:

1. TMR1 interrup t. T imer1 m ust be ope rating as an

asynchronous counter.

2. CCP Capture mode interrupt.

3. Special event trigger (Timer1 in Asynchronous

mode using an external clock).

4. SSP (Start/Stop) bit detect interrupt.

5. SSP transmit or receive in Slave mode (SPI/I2C).

6. A/D conversion (when A/D clock source is RC).

7. EEPROM write operation completion.

Other peripherals cannot generate interrupts since

during Sleep, no on-chip clocks are present.

When the SLEEP instruction is being executed, the next

instruction (PC + 1) is prefetched. For the device to

wake-up thro ugh an interrupt eve nt, the corres pon din g

interrupt enable bit must be set (enabled). Wake-up

occurs regardless of the state of the GIE bit. If the GIE

bit is clear (disabled), the device continues execution at

the ins truction a fter the SLEEP i nstructio n. If the GI E bit

is set (enabled), the device executes the instruction

after the SLEEP instruction and then branches to the

interrupt address (0004h). In cases where the

execution of the instruction following SLEEP is not

desirable, the user should have a NOP after the SLEEP

instruction.

12.13.2 WAKE-UP USING INTERRUPTS

When global interrupts are disabled (GIE cleared) and

any interrupt source has both its interrupt enable bit

and inte rrupt fla g bit s et, one of the fo llow ing wil l occur:

• If the interrupt occurs before the execution of a

SLEEP instruction, the SLEEP instruction will

comple te as a NOP. Therefore, th e WDT and WDT

pos tscaler will not be cleared, the TO bit will not

be set and PD bit will not be cleared.

• If the interrupt occurs during or after the

execution of a SLEEP instructio n, the dev ic e wi ll

immediately wake-up from Sleep. The SLEEP

instruction will be completely executed before the

wake-up. Therefore, the WDT and WDT

pos tscaler will be cleared, the TO bit will be set

and the PD bit 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 inst ruction completes. To

determine whether a SLEEP instru ction ex ecuted , test

the PD bit. If the PD bit is set, the SLEEP instruction

was executed as a NOP.

To ensure that the WDT is cleared, a CLRWDT instruction

should be executed before a SLEEP instru ction.

PIC16F818/819

DS39598E-page 100  2004 Microchip Technology Inc.

FIGURE 12-9: WAKE-UP FROM SLEEP THROUGH INTERRUPT

12.14 In-Circuit Debugger

When the DEBUG bit in the Configuration Word is

progra mmed to a ‘0’, the In-Circuit D ebugger function-

ality is enabled . This function allows simple debuggin g

functions when used with MPLAB® ICD. When the

microcontroller has this feature enabled, some of the

resources ar e no t avai labl e for ge ner al use . Tabl e 1 2- 6

shows which features are consumed by the background

debugger.

TABLE 12-6: DEBUGGER RESOURCES

To use the In-Circuit Debugger function of the micro-

controller, the design must implement In-Circuit Serial

Programming connections to MCLR/VPP, VDD, GND,

RB7 and RB6. This will interface to the in-circuit

debugger module available from Microchip or one of

the third party development tool companies.

12.15 Program Verification/Code

Protection

If the code protection bit(s) have not been

programmed, the on-chip program memory can be

read out for verification purposes.

12.16 ID Locations

Four memory locations (2000h-2003h) are designated

as ID locations, where the user can store checksum or

other code identification numbers. These locations are

not accessible during normal execution but are

readable and writable during program/verify. It is

recommended that only the four Least Significant bits

of the ID location are used.

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

CLKO(4)

INT pin

INTF Flag

(INTCON<1>)

GIE bit

(INTCON<7>)

INSTRUCTION FLOW

Instruction

Fetched

Instruction

Executed

PC PC + 1 PC + 2

Inst(PC) = Sleep

Inst(PC – 1)

Inst(PC + 1)

Sleep

Processor in

Sleep

Interru pt Late ncy

(Note 2)

Inst(PC + 2)

Inst(PC + 1)

Inst(0004h) Inst(0005h)

Inst(0004h)

Dummy Cycle

PC + 2 0004h 0005h

Dummy Cycle

TOST(2)

PC + 2

Note 1: XT, HS or LP Oscillator mode assumed.

2: TOST = 1024 TOSC (drawing not to scale). This delay will not be there for RC Oscillator mode.

3: GIE = 1 assumed. In this case, after wake-up, the processor jumps to the interrupt routine. If GIE = 0, execution will continue in-line.

4: CLKO is not available in these oscillator modes but shown here for timing reference.

I/O pins RB6, RB7

Stack 1 level

Program Memory Address 0000h must be NOP

Last 100h wor ds

Data Memory 0x070 (0x0F0, 0x170, 0x1F0)

0x1EB-0x1EF

 2004 Microchip Technology Inc. DS39598E-page 101

PIC16F818/819

12.17 In-Circuit Serial Programming

PIC16F818/819 microcontrollers can be serially

progra mmed w hile in t he en d app licati on c ircuit. This i s

simply done with tw o lines for cl ock and data and thre e

other lines for power, ground and the programming

volt age (see Figure 12-10 for an ex amp le ) . Thi s a llo ws

customers to manufacture boards with unprogrammed

devices and then program the microcontroller just

before shipping the product. This also allows the most

recent firmware or a custom firmware to be

programmed.

For more information on serial programming, please refer

to the “PIC16F818/819 Flash Memory Programming

Specification” (DS39603).

FIGURE 12-10: TYPICAL IN-CIRCUIT

SERIAL PROGRAMMING

CONNECTION

Note: The Timer1 oscillator shares the T1OSI

and T1OSO pins with the PGD and PGC

pins used for programming and

debugging.

When using the Timer1 oscillator, In-Circuit

Serial Programming™ (ICSP™) may not

function correctly (high voltage or low

voltage) or the In-Circuit Debugger (ICD)

may not communicate with the controller.

As a result of using either ICSP or ICD, the

Time r1 crystal may be dam aged.

If ICSP or ICD operatio ns are requi red, the

crystal should be disconnected from the

circuit (disconnect either lead) or installed

after programming. The oscillator loading

capacitors may remain in-circuit during

ICSP or ICD operation.

External

Connector

Signals

To Normal

Connections

To Normal

Connections

PIC16F818/819

VDD

VSS

MCLR/VPP

RB6

RB7

+5V

VPP

CLK

Data I/O

VDD

* * *

* Isolation devices (as required).

† RB3 only used in LVP mode.

RB3†

RB3/PGM

PIC16F818/819

DS39598E-page 102  2004 Microchip Technology Inc.

12.18 Low- Voltage ICSP Progra mming

The LVP bit of the Configurat ion Word registe r enable s

Low-V ol tage ICSP Program ming. This mode all ows the

microcontroller to be programmed via ICSP using a

VDD source in the operating voltage range. This only

means that VPP does not have to be brought to V IHH but

can instead be left at the normal operating voltage. In

this mode, the RB3/PGM pin is dedicated to the

programming function and ceases to be a general

purpose I/O p in.

If Low-V oltage Programming mode is not used, the LVP

bit can be programmed to a ‘ 0’ and RB3/PGM be comes

a digital I/O pin. However, the LVP bit may only be

programm ed whe n Pro gram m ing m ode is entered w i th

VIHH on MCLR. The LVP bit ca n only be cha nged whe n

using high voltage on MCLR.

It should be noted that once the LVP bit is programmed

to ‘0’, only the High-Voltage Programming mode is

available and only this mode can be used to program

the device.

When using Low-Voltage ICSP, the part must be

supplied at 4.5V to 5.5V if a bulk erase will be ex ecuted.

This includes reprogramming of the code-protect bits

from an ON state to an OFF state. For all other cases of

Low-Voltage ICSP, the part may be programmed at the

normal operating voltage. This means calibration values,

unique user IDs or user code can be reprogrammed or

added.

The following LVP step s assume the LVP bit is set in the

Configuration Wo rd register.

1. Apply VDD to the VDD pin.

2. Drive MCLR low.

3. Apply VDD to the RB3/PGM pin.

4. Apply VDD to the MCLR pin.

5. Follow with the associated programming steps.

Note 1: The High-Voltage Programming mode is

always available, regardless of the state

of the LVP bit, by applying VIHH to the

MCLR pin.

2: While in Low-Voltage ICSP mode

(LVP = 1), the RB3 pin can no longer be

used as a general purpose I/O pin.

3: When using Low-Voltage ICSP Program-

ming (LVP) and the pull-ups on PORTB

are enabled, bit 3 in the TRISB register

must be cleared to disable the pull-up on

RB3 and ensure the proper operation of

the device.

4: RB3 should not be allowed to float if LVP

is enabled. An external pull-down device

should be used to default the device to

normal operating mode. If RB3 floats

high, the PIC16F818/819 device will

enter Programming mode.

5: LVP mode is enabled by default on all

device s shippe d from Microchi p. It can b e

disabled by clearing the LVP bit in the

Configuration Word register.

6: Disabling LVP will provide maximum

compatibility to other PIC16CXXX

devices.

 2004 Microchip Technology Inc. DS39598E-page 103

PIC16F818/819

13.0 INSTRUCTION SET SUMMARY

The PIC16 instruction set is highly orthogonal and is

comprised of three basic categories:

•Byte-oriented operations

•Bit-oriented operations

•Literal and cont rol operations

Each PIC16 instruction is a 14-bit word divided into an

opcode, which specifi es the instructi on type and one or

more operands, which further specify the operation of

the instruction. The formats for each of the categories

are presen ted in Fig ure 13-1, while the vari ous op code

fields are sum m ariz ed in Table 13-1.

Table 13-2 lists the instructions recognized by the

MPASMTM assembler. A complete description of each

instruction is also available in the “PICmicro® Mid-Range

MCU Family Re ference Man ual” (DS33023).

For byte-oriented instructions, ‘f’ represents a file

designator. The file register designator specifies which

file register is to be used by the instruction.

The desti nation designator specifies where the result of

the operation is to be placed. If ‘d’ is zero, the result is

placed in the W regis ter . If ‘d’ is one, the res ult is place d

in the file register specified in the instruction.

For bit-oriented instructions, ‘b’ represents a bit field

design ator, which selects the bi t affected by the ope ra-

tion, w hi le ‘f’ represent s th e a ddress of the fi le in which

the bit is located.

For literal and control operations, ‘k’ represents an

eight or eleven-bit constant or literal value

One instr uction cycle co nsists of four os cillator periods .

For an oscill ator fre quenc y of 4 MHz, this giv es a nor-

mal instruction execution time of 1 µs. All instructions

are executed within a single instruction cycle, unless a

conditional test is true, or the program counter is

change d as a result of an instruction. When this occurs,

the execution takes two instruction cycles, with the

second cycle executed as a NOP.

All instruction examples use the format ‘0xhh’ to

represent a hexadecimal number, where ‘h’ signifies a

hexadecimal digit.

13.1 READ-MODIFY-WRITE

OPERATIONS

Any instruction that specifies a file register as part of

the instruction performs a Read-Modify-Write (R-M-W)

operatio n. The register is read, the data is modi fied and

the resul t is stored ac cording to e ither the ins truction or

the destination designator ‘d’. A read operation is

perfor me d on a regi st er ev en if the ins truction w ri tes to

that register.

For example, a “CLRF PORTB” instruction will read

PORTB, clear all the data bits, then write the result

back to PORTB. This example would have the

unintended result that the condition that sets the RBIF

flag would be cleared.

TABLE 13-1: OPCODE FIELD

DESCRIPTIONS

FIGURE 13-1: GENERAL FORMAT FOR

INSTRUCTIONS

Note: To maintain upward compatibility with

future PIC16F818/819 products, do not

use the OPTION and TRIS instructions.

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.

PC Program Counter

TO Time-out bit

PD Power-Down bit

Byte-orie nted file re gister op erations

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 operati ons

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

PIC16F818/819

DS39598E-page 104  2004 Microchip Technology Inc.

TABLE 13-2: PIC16F818/819 INSTRUCTION SET

Mnemonic,

Operands Description Cycles 14-Bit Opcode Status

Affected Notes

MSb LSb

BYTE-ORIENTED FILE REGISTER OPERATIONS

ADDWF

ANDWF

CLRF

CLRW

COMF

DECF

DECFSZ

INCF

INCFSZ

IORWF

MOVF

MOVWF

NOP

RLF

RRF

SUBWF

SWAPF

XORWF

f, d

Add W and f

AND W with f

Clear f

Clear W

Complement f

Decrement f

Decrement f, Skip if 0

Increment f

Increment f, Skip if 0

Inclusive OR W with f

Move f

Mov e W to f

No Operation

Rotate L e ft f thro ugh Carry

Rotate Right f through Carry

Subtract W from f

Swap nibbles in f

Exclusive OR W with f

1 (2)

0111

0101

0001

1001

0011

1011

1010

1111

0100

1000

0000

1101

1100

0010

1110

0110

dfff

lfff

0xxx

dfff

lfff

0xx0

dfff

ffff

xxxx

ffff

0000

ffff

C, DC, Z

1, 2

1, 2, 3

1, 2

1, 2, 3

1, 2

BIT-ORIENTED FILE REGISTER OPERATIONS

BCF

BSF

BTFSC

BTFSS

f, b

Bit Clear f

Bit Se t f

Bit Test f, Skip if Clear

Bit Test f, Skip if Set

1 (2)

00bb

01bb

10bb

11bb

bfff

ffff

1, 2

LITERAL AND CONTROL OPERATIONS

ADDLW

ANDLW

CALL

CLRWDT

GOTO

IORLW

MOVLW

RETFIE

RETLW

RETURN

SLEEP

SUBLW

XORLW

Add literal and W

AND literal with W

Call subroutine

Clear Watchdog Timer

Go to address

Inclusive OR literal with W

Move litera l to W

Return from interrupt

Return with literal in W

Return from Subroutine

Go into Standby mode

Subtract W from literal

Exclusive OR literal with W

111x

1001

0kkk

0000

1kkk

1000

00xx

0000

01xx

0000

110x

1010

kkkk

0110

kkkk

0000

kkkk

0000

0110

kkkk

0100

kkkk

1001

kkkk

1000

0011

kkkk

C, DC, Z

TO, PD

C, DC, Z

Note 1: When an I/O register is modified as a function of itself ( e.g., MOVF PORTB, 1), the value used will be that value

present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is driven low by an

external device, the data will be written back with a ‘0’.

2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared if

assigned to the Timer0 module.

3: 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.

Note: Additional information on the mid-range instruction set is available in the “PICmicro® Mid-Range MCU

Family Reference Manual” (DS33023).

 2004 Microchip Technology Inc. DS39598E-page 105

PIC16F818/819

13.2 Instruction Descriptions

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

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

Desc ription: Add the con tents of the W re gister

with reg ister ‘f’. If ‘d’ = 0, the resu lt

is stored in the W register. If

‘d’ = 1, the resu lt i s sto r ed ba ck in

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

ANDed with the ei ght-bit literal ‘k’.

The result is placed in the W

ANDWF AND W with f

Syntax: [ label ] ANDWF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (W) .AND. (f) → (destinati on)

Status Affected: Z

Description: AND the W register with register

‘f’. If ‘d’ = 0, the result is stored in

the W regis ter. If ‘d’ = 1, the result

is stored back in register ‘f’.

BCF Bit Clear f

Syntax: [ label ] BCF f,b

Operands: 0 ≤ f ≤ 12 7

0 ≤ b ≤ 7

Operation: 0 → (f<b>)

Status Affected: None

Description: Bit ‘b’ in register ‘f’ is cleared.

BSF Bit Set f

Syntax: [ label ] BSF f,b

Operands: 0 ≤ f ≤ 12 7

0 ≤ b ≤ 7

Operation: 1 → (f<b>)

Status Affected: None

Description: Bit ‘b’ in register ‘f’ is set.

PIC16F818/819

DS39598E-page 106  2004 Microchip Technology Inc.

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’ = 0, the next

instructi on is exec uted .

If bit ‘b’ = 1, then the next

instructi on is d is ca rded and a NOP

is exec ute d i nst ead, mak ing thi s a

2 TCY instruction.

BTFSC Bit Test, 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’ = 1, the next

instruction is executed.

If bit ‘b’ in register ‘f’ = 0, the next

inst ruc tion is di sc ard ed and a NOP

is exec ute d ins te ad, m ak in g thi s a

2 TCY instruct ion.

CALL Call Subroutine

Syntax: [ label ] CALL k

Operands: 0 ≤ k ≤ 204 7

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 loa ded from PC LATH.

CALL 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 se t.

CLRWDT Clear Watchdog Ti mer

Syntax: [ label ] CLRWDT

Operands: None

Operation: 00h → WDT

0 → WDT prescaler,

1 → TO

1 → PD

Status Affected: T O , PD

Description: CLRWDT instruction resets the

W atchdog T imer . It also resets the

prescaler of the WDT. Status bits

TO and PD are set.

 2004 Microchip Technology Inc. DS39598E-page 107

PIC16F818/819

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

complemented. If ‘d’ = 0, the

result is stored in W. If ‘d’ = 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’ = 0,

the result is stored in the W

stored back in register ‘f’.

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

decremented. If ‘d’ = 0, the result

is placed in the W register. If

‘d’ = 1, the result is placed back in

If the result is ‘1’, the next

instruction is executed. If the

resu lt is ‘0’, then a NOP is

executed instead, making it a

2 TCY 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 e lev en -bit im me dia t e v alu e i s

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

incremented. If ‘d’ = 0, the result

is placed in the W register. If

‘d’ = 1, the resul t is placed back in

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

incremen ted. If ‘d’ = 0, th e result is

placed in the W register. If ‘d’ = 1,

the result is placed back in

If the result is ‘1’, the next

instruction is executed. If the

result is ‘0’, a NOP is executed

instead, making it a 2 TCY

instruction.

PIC16F818/819

DS39598E-page 108  2004 Microchip Technology Inc.

IORLW Inclusive OR Literal with W

Syntax: [ label ] IORLW k

Operands: 0 ≤ k ≤ 255

Operation: (W) .OR. k → (W)

Status Affected: Z

Desc ription: The con tents of t he W register are

ORed with the eight-bit literal ‘k’.

The result is placed in the W

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

placed in th e W re gis ter. If ‘d’ = 1,

the result is placed back in

MOVF Move f

Syntax: [ label ] MOVF f,d

Operands: 0 ≤ f ≤ 127

d ∈ [0,1]

Operation: (f) → (destinati on )

Status Affected: Z

Description: The contents of register ‘f’ are

moved t o a destination dependant

upon the status of ‘d’. If ‘d’ = 0,

the destination is W register. If

‘d’ = 1, th e desti nat ion is fi le regi s-

ter ‘f’ itself. ‘d’ = 1 is useful to test

a file register since status flag Z is

affected.

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 assemble as ‘0’s.

MOVWF Move W to f

Syntax: [ label ] MOVWF f

Operands: 0 ≤ f ≤ 12 7

Operation: (W) → (f)

Status Affected: None

Description: Move data from W register to

NOP No Operation

Syntax: [ label ] NOP

Operands: None

Operation: No operation

Status Affected: None

Description: No operation.

 2004 Microchip Technology Inc. DS39598E-page 109

PIC16F818/819

RETFIE Return from Interrupt

Syntax: [ label ] RETFIE

Operands: None

Operation: TOS → PC,

1 → GIE

Status Affected: None

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.

RETURN Return from Subroutine

Syntax: [ label ] RETURN

Operands: None

Operation: TOS → PC

Status Affected: None

Description: Return from subroutine. The stack

is POPed an d t he top o f th e s t a ck

(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 C arry flag . If ‘ d’ = 0, the res ult

is placed in the W register. If

‘d’ = 1, the result is st ored back in

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

rotate d one bit to the righ t through

the Carry flag. If ‘d’ = 0, the result

is placed in the W register. If

‘d’ = 1, the result is placed back in

SLEEP Enter Sleep mode

Syntax: [ label ]SLEEP

Operands: None

Operation: 00h → WDT,

0 → WDT prescaler,

1 → TO,

0 → PD

Status Affected: TO, PD

Descripti on : The Power-Down st atu s bit, PD,

is cleared. Time-out status bit,

TO, is set. Watchdog Timer and

its prescaler are cleared.

The processor is put into Sleep

mode with the os cillator stopped.

PIC16F818/819

DS39598E-page 110  2004 Microchip Technology Inc.

SUBLW Subtract W from Literal

Syntax: [ label ] SUBLW k

Operands: 0 ≤ k ≤ 255

Operation: k – (W) → (W)

Status Affected: C, DC, Z

Desc ript ion : The W register is su btra cte d (2’ s

complement method) from the

eight-bit literal ‘k’. The result is

placed in the W regi ster.

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’ = 0, the result is stored in the W

stored back in register ‘f’.

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

‘d’ = 0, the result is placed in W

placed in register ‘f’.

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 XORed with the eight-b it

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’ = 0, the result is stored in the

W register. If ‘d’ = 1, the result is

stored back in register ‘f’.

 2003 Microchip Technology Inc. DS39598D-page 111

PIC16F818/819

14.0 DEVELOPMENT SUPPORT

The PICmicro® microcontrollers are supported with a

full ran ge of hardware a nd softwa re develo pment to ols:

• Integrated Development Environment

- MPLAB® IDE Software

• Assemblers/Compilers/Linkers

- MPASMTM Assembler

- MPLAB C17 and MPLAB C18 C Compilers

-MPLINK

TM Object Linker/

MPLIBTM Object Librarian

- MPLAB C30 C Compiler

- MPLAB ASM30 Assembler/Linker/Library

• Simulators

- MPLAB SIM Software Simulator

- MPLAB dsPIC30 Software Simulator

•Emulators

- MPLAB ICE 2000 In-Circuit Emulator

- MPLAB ICE 4000 In-Circuit Emulator

• In-Circuit Debugger

- MPLAB ICD 2

• Device Progra mmers

-PRO MATE

® II Univer sa l D evi ce Pro gr a mm er

- PICSTART® Plus Development Programmer

- MPLAB PM3 Device Programmer

• Low-Cost Demonstration Boards

- PICDEMTM 1 Demonstration Board

- PICDEM.netTM De monstration Board

- PICDEM 2 Plus Demonstration Board

- PICDEM 3 Demonstration Board

- PICDEM 4 Demonstration Board

- PICDEM 17 Demonstration Board

- PICDEM 18R Demonstration Board

- PICDEM L IN Demo nstration Board

- PICDEM USB Demonstration Board

• Evaluation Kits

-K

EELOQ® Evaluation and Programming Tools

- P ICDEM MSC

-microID

® Developer Kits

-CAN

- PowerSmart® Developer Kits

-Analog

14.1 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®

based application that contains:

• An interface to deb ugging 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

• Mouse over variable inspection

• Exten si ve on-l in e help

The MPLAB IDE allows you to:

• Edit your sour ce fil es (either assembly or C)

• One touch assemble (or compile) and download

to PICmicro emulator and simulator tools

(automatically updates all project information)

• Debug us ing :

- source files (as sembl y 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 whe n upgrading to tools with increasin g flexibi lity

and power.

14.2 MPASM Assembler

The MPASM assembler is a full-featured, universal

macro assembler for all PICmicro MCUs.

The MPASM assembler generates relocatable object

files for the MPLINK object linker, Intel® standard HEX

files, M AP files to detail memory u sage and symbol re f-

erence, a bsolute LST files that cont ain source lines and

generated machine code and COFF files for

debugging.

The MPASM assembler features include:

• Integration into MPLAB IDE projects

• User de fined m acros to strea mline asse mbly cod e

• Condit ion al as sem bl y for mult i-p urpo se sourc e

files

• Directives that allow complete control over the

assembly p rocess

PIC16F818/819

DS39598D-page 112  2003 Microchip Technology Inc.

14.3 MPLAB C17 and MPLAB C18

C Compilers

The MPLAB C17 and MPLAB C18 Code Development

Systems are complete ANSI C compilers for

Microchip’s PIC17CXXX and PIC18CXXX family of

microcontrollers. 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 info rmation tha t is optimized to the MPLAB IDE

debugger.

14.4 MPLINK Object Linker/

MPLIB Object Librari an

The MPLINK object linker combines relocatable

objects created by the MPASM assembler and the

MPLAB C17 and MPLAB C18 C compilers. 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 extr action

14.5 MPLAB C30 C Compiler

The MPLAB C30 C compiler is a full-featured, ANSI

compliant, optimizing compiler that translates standard

ANSI C programs into dsPIC30F assembly language

source. The compiler also supports many command

line options and language extensions to take full

adv antage of the dsPIC 30F dev ice ha rdwar e capab ili-

ties and afford fine control of the compiler code

generator.

MPLAB C30 is distributed with a complete ANSI C

standard library. All library functions have been vali-

dated an d c on form to the ANSI C li brary standard . Th e

library includes functions for string manipulation,

dynamic memory allocation, data conversion, time-

keepin g and math func tions (trigonome tric, expone ntial

and hyperbolic). The compiler provides symbolic

information for high-level source debugging with the

MPLAB IDE.

14.6 MPLAB ASM30 Assembler, Linker

and Librarian

MPLAB ASM30 assembler produces relocatable

machine code from symbolic assembly language for

dsPIC30F devices. MPLAB C30 compiler uses the

assembler to produce it’s object file. The assembler

generates relocatable object files that can then be

archived or lin ked with other relocatable ob ject files and

arch ives to c rea te an e xecu tabl e fil e. N otabl e fe atu res

of the assembler include:

• Support for the entire dsPIC30F instruction set

• Support for fixed-point and floating-point data

• Command line interface

• Rich dire cti ve set

• Flexible macro language

• MPLAB IDE compatibility

14.7 MPLAB SIM Software Simulator

The MPLAB SIM sof tware simulat or allows code deve l-

opment in a PC hosted environment by simulating the

PICmicro series microcontrollers on an instruction

level. On any given instruction, the data areas can be

examined or modified and stimuli can be applied from

a file, or use r de fined key p ress, to any pin. The exec u-

tion can be performed in Single-Step, Execute Until

Break or Trace mode.

The MPLAB SIM simulator fully supports symbolic

debugging using the MPLAB C17 and MPLAB C18

C Compilers, as well as the MPASM assembler. The

software simulator offers the flexibility to develop and

debug code outside of the laboratory environment,

making it an excellent, economical software

development tool .

14.8 MPLAB SIM30 Software Simulator

The MPLAB SIM30 software simulator allows code

develop ment in a PC hosted en vironment by simulating

the dsPIC30F series microcontrollers on an instruction

level. On any given instruction, the data areas can be

examined or modified and stimuli can be applied from

a file, or user defined key press, to any of the pins.

The MPLAB SIM30 simulator fully supports symbolic

debugging using the MPLAB C30 C Compiler and

MPLAB ASM30 assembler . The simula tor runs in either

a Command Line mode for automated tasks, or from

MPLAB IDE. This high-speed simulator is designed to

debug, analyze and optimize time intensive DSP

routines.

 2003 Microchip Technology Inc. DS39598D-page 113

PIC16F818/819

14.9 MPLAB ICE 2000

High-Performance Universal

In-Circui t Emu lator

The MPLAB ICE 2000 universal in-circuit emulator is

intended to provide the product development engineer

with a complete microcontroller design tool set for

PICmicro microcontrollers. Software control of the

MPLAB ICE 2000 in-circuit emulator is advanced by

the MPLAB Integrated Development Environment,

which all ows ed iting, b uildin g, do wnlo ading and sourc e

debuggi ng from a singl e envi ronm en t.

The MPLAB ICE 2000 is a full-featured emulator sys-

tem with enhanced trace, trigger and data monitoring

featur es. Interchangea ble processo r modules al low the

system to be easi ly reconfi gured for emula tion of d iffer-

ent processors. The universal architecture of the

MPLAB ICE in-circuit emulator allows expansion to

support new PICmicro 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.

14.10 MPLAB ICE 4000

High-Performance Universal

In-Circui t Emu lator

The MPLAB ICE 4000 universal in-circuit emulator is

intended to provide the product development engineer

with a co mplete micro controller de sign tool se t for high-

end PICmicro microcontrollers. Software control of the

MPLAB ICE in-circuit emulator is provided by the

MPLAB Integrated Development Environment, which

allows editing, building, downloading and source

debuggi ng from a singl e envi ronm en t.

The MPLAB ICD 4000 is a premium emulator system,

providing the features of MPLAB ICE 2000, but with

increased emulation memory and high-speed perfor-

mance for dsPIC30F and PIC18XXXX devices. Its

advanc ed emulator fe atures inc lude complex t riggering

and timing, up to 2 Mb of emulation memory and the

ability to view variables in real-time.

The MPLAB ICE 4000 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.

14.11 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

PICmicro MCUs and can be used to develop for these

and other PICmicro microcontrollers. 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 , offe rs cost ef fective i n-circuit Flash debug ging

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-stepping and watching variables,

CPU status and peripheral registers. Running at full

speed enables testing hardware and applications in

real-tim e. MPLAB ICD 2 also serves as a devel opment

programmer for selected PICmicro devices.

14.12 PRO MATE II Universal Device

Programmer

The PRO MATE II is a universal, CE compliant device

programmer with programmable voltage verification at

VDDMIN and VDDMAX for maxi mum reli abili ty. It fea tures

an LCD display for instructions and error messages

and a modular detachable socket assembly to support

various package types. In Stand-Alone mode, the

PRO MATE II device programmer can read, verify and

program PICmicro devices without a PC connection. It

can also set code protection in this mode.

14.13 MPLAB PM3 Device Programmer

The MPLAB PM3 is a universal, CE compliant device

programmer with programmable voltage verification at

VDDMIN and VDDMAX for maxi mum reli abili ty. It fea tures

a large LCD display (128 x 64) for menus and error

messages and a modular detachable socket assembly

to support various package types. The ICSP™ cable

assembly is included as a standard item. In Stand-

Alone mode , the M PLAB PM3 devi ce pr ogra mmer ca n

read, verify and program PICmicro devices without a

PC connection. It can also set code protection in this

mode. M PLAB PM3 con nects t o the host PC via an RS-

232 or USB cable. MPLAB PM3 has high-speed com-

munications and optimized algorithms for quick pro-

gramming of large memory devices and incorporates

an SD/ MMC card fo r file s torage an d secure d ata a ppli-

cations.

PIC16F818/819

DS39598D-page 114  2003 Microchip Technology Inc.

14.14 PI CSTART Plus Development

Programmer

The PICSTART Plus development programmer is an

easy-to-use, low-cost, prototype programmer. It con-

nects to the PC via a COM (RS-232) port. MPLAB

Inte grated Dev elopmen t En vironme nt so ftware makes

using the programmer simple and efficient. The

PICSTART Plus development programmer supports

most PICmicro devices 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.

14.15 PI CDEM 1 PICmicro

Demonstration Board

The PICDEM 1 demo nstrat ion boa rd demo nstrate s the

capabilities of the PIC16C5X (PIC16C54 to

PIC16C58A), PIC16C61, PIC16C62X, PIC16C71,

PIC16C8X, PIC17C42, PIC17C43 and PIC17C44. All

necessary hardware and software is included to run

basic demo programs. The sample microcontrollers

provi d ed wi t h the P IC DE M 1 de mo ns t rat i on b oar d c an

be pro gramme d with a PRO MATE I I devi ce prog ram-

mer or a PICSTART Plus development programmer.

The PICDE M 1 demonstrati on board can be conne cted

to the MPLAB ICE in-circuit emulator for testing. A

proto type area extends the ci rcuitry for a dditio nal appli-

cation components. Features include an RS-232

interface, a potentiometer for simulated analog input,

push button switches and eight LEDs.

14.16 PICDEM.net In ternet/Ether net

Demonstration Board

The PICDEM.net demonstration board is an Internet/

Ethernet demonstration board using the PIC18F452

microcontroller and TCP/IP firmware. The board

supports any 40-pin DIP device that conforms to the

standard pinout used by the PIC16F877 or

PIC18C452. This kit features a user friendly TCP/IP

stack, web server with HTML, a 24L256 Serial

EEPROM for Xmodem download to web pages into

Serial EEPROM, ICSP/MPLAB ICD 2 interface con-

nector, an Ethernet interface, RS-232 interface and a

16 x 2 LCD display. Also included is the book and

CD-ROM “TCP/IP Lean, Web Servers for Embedded

Systems,” by Jeremy Bentham

14.17 PI CDEM 2 Plus

Demonstration Board

The PICDEM 2 Plus demonstration board supports

many 18, 28 and 40-pin microcontrollers, including

PIC16F87X and PIC18FXX2 devices. All the neces-

sary ha rdware and s oftware is included to run the dem-

onstration programs. The sample microcontrollers

provided with the PICDEM 2 demonstration board can

be programmed with a PRO MATE II device program-

mer, PICSTART Plus development programmer, or

MPLAB ICD 2 with a Universal Programmer Adapter.

The MPLAB I CD 2 and MPLAB ICE in-circuit emul ators

may also be used with the PICDEM 2 demonstration

board to test firmware. A prototype area extends the

circuitry for additional application components. Some

of the features include an RS-232 interface, a 2 x 16

LCD display, a piezo speaker , an o n-board temperatu re

sensor, four LEDs and sample PIC18F452 and

PIC16F877 Flash microcontrollers.

14.18 PI CDEM 3 PIC16C92X

Demonstration Board

The PICDEM 3 demonstration board supports the

PIC16C923 and PIC16C924 in the PLCC package. All

the necessary hardware and software is included to run

the demonstration programs.

14.19 PI CDEM 4 8/14/18-Pin

Demonstration Board

The PICDEM 4 can be used to demonstrate the capa-

bilities of the 8, 14 and 18-pin PIC16XXXX and

PIC18XXXX MCUs, including the PIC16F818/819,

PIC16F87/88, PIC16F62XA and the PIC18F1320

family of microcontrollers. PICDEM 4 is intended to

showcase the many features of these low pin count

parts, including LIN and Motor Control using ECCP.

Special provisions are made for low-power operation

with the supercapacitor circuit and jumpers allow on-

board hardware to be disabled to eliminate current

draw in this mode. Included on the demo bo ard are pro-

visions for Crystal, RC or Canned Oscillator modes, a

five volt regulator for use with a nine volt wall adapter

or battery, DB-9 RS-232 interface, ICD connector for

programming via ICSP and development with MPLAB

ICD 2, 2 x 16 liqui d crystal dis play, PC B footp rints for

H-Bridge motor driver, LIN transceiver and EEPROM.

Also in clude d are: head er for expansi on, eig ht L EDs,

four potentiometers, three push buttons and a proto-

typi ng are a. Incl uded wit h the ki t is a P IC16F62 7A and

a PIC18F1320. Tutorial firmware is included along

with th e User’s Guide.

 2003 Microchip Technology Inc. DS39598D-page 115

PIC16F818/819

14.20 PI CDEM 17 Demonstration Board

The PICDEM 17 demonstration board is an evaluation

board that demonstrates the capabilities of several

Microchip microcontrollers, including PIC17C752,

PIC17C756A, PIC17C762 and PIC17C766. A pro-

gramme d sample i s included. The PR O MA TE I I device

programmer, or the PICSTART Plus development pro-

gramme r , can be used to reprogram the device for user

tailored application development. The PICDEM 17

demonstration board supports program download and

execution from external on-board Flash memory. A

generous proto typ e area is av ailab le for user hardw are

expansion.

14.21 PI CDEM 18R PIC18C601/801

Demonstration Board

The PICDEM 18R demonstration board serves to assist

development of the PIC18C601/801 family of Microchip

microcontrollers. It provides hardware implementation

of both 8-bit Multiplexed/Demultiplexed and 16-bit

Memory modes. The board includes 2 Mb external

Flash memory and 128 Kb SRAM memory, as well as

serial EEPROM, allowing access to the wide range of

memory types supported by the PIC18C601/801.

14.22 PI CDEM LIN PIC16C43X

Demonstration Board

The pow erfu l LI N hard w are a nd s of tw are kit inclu des a

series of boards and three PICmicro microcontrollers.

The small footprint PIC16C432 and PIC16C433 are

used as slaves in the LIN communication and feature

on-board LIN transceivers. A PIC16F874 Flash

microcontroller serves as the master. All three micro-

controllers are programmed with firmware to provide

LIN b us communication.

14.23 PICkitTM 1 Flash Starter Kit

A complete “developmen t system in a box”, the PICkit™

Flash Starter Kit includes a convenient multi-section

board for programming, evaluation and development of

8/14-pin Flash PIC® microc ontrollers. Powered via USB,

the board operates under a simple Windows GUI. The

PICkit 1 Starter Kit includes the User’s Guide (on CD

ROM), PICkit 1 tutorial software and code for various

applications. Also included are MPLAB® IDE (Integrated

Development Environment) software, software and

hardware “Tips 'n Tricks for 8-pin Flash PIC®

Microcontrollers” Handbook and a USB interface cable.

Supports all current 8/14-pin Flash PIC microc ontrollers,

as well as many future planned dev ices .

14.24 PI CDEM USB PIC16C7X5

Demonstration Board

The PICDEM U SB Demo ns trati on Board sho w s o f f th e

capabilities of the PIC16C745 and PIC16C765 USB

microcontrollers. This board provides the basis for

future USB products.

14.25 Eval uation and

Programming Tools

In additio n to the PICDEM seri es of circuits, Microchip

has a line of evaluation kits and demonstration software

for the se products.

•K

EELOQ evaluation and prog ram mi ng too ls for

Microchip’s HCS Secure Data Products

• CAN developers kit for automotive network

applications

• Analog design boards and filter design software

• PowerS mart battery charging evaluation/

calibration kits

•IrDA

® development kit

• microID development and rfLabTM development

software

• SEEVAL® designer kit f or m em ory evaluation and

endurance calculations

• PICDEM MSC demo boards for Switching mode

power supply, high-power IR driver, delta sigma

ADC and flow rate sensor

Check the Microchip web page and the latest Product

Selector Guide for the complete list of demonstration

and evaluation kits.

PIC16F818/819

DS39598D-page 116  2003 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 117

PIC16F818/819

15.0 ELECTR ICAL CHARACTERISTICS

Absolute Maximum Ratings †

Ambient temperature under bias............................................................................................................ -40°C to +125°C

Storage temperature.............................................................................................................................. -65°C to +150°C

Voltage on any pin with respect to VSS (except VDD and MCLR) ...................................................-0.3V to (VDD + 0.3V)

Voltage on VDD with respect to VSS ............................................................................................................ -0.3 to +7.5V

Voltage on MC LR with respect to VSS (Note 2).............................................................................................-0.3 to +14V

Total powe r dissipation (Note 1) ..................................................................................................................................1W

Maximum curr ent out of VSS pin ...........................................................................................................................200 mA

Maximum curr ent into VDD pin..............................................................................................................................200 mA

Input clamp current, IIK (VI < 0 or VI > VDD)..........................................................................................................±20 mA

Output clamp cur rent, IOK (VO < 0 or VO > 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

Maximum curr ent sunk by PORTA........................................................................................................................100 mA

Maximum current sourced by PORTA...................................................................................................................100 mA

Maximum curr ent sunk by PORTB........................................................................................................................100 mA

Maximum current sourced by PORTB..................................................................................................................100 mA

Note 1: Power dissip ation i s calcu lated as foll ows: Pdi s = VDD x { IDD – ∑ IOH} + ∑ {(VDD – V OH) x IOH} + ∑(VOL x IOL)

2: Voltage spikes at the MCLR pin may cause latch-up. A series resistor of greater than 1 kΩ should be used

to pull MCLR to VDD, rather than tying the pin directly to VDD.

† 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 to maximum rating conditions for

extended periods may affect device reliability.

PIC16F818/819

DS39598E-page 118  2004 Microchip Technology Inc.

FIGURE 15-1: PIC16F818/819 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL, EXTENDED)

FIGURE 15-2: PIC16LF818/819 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)

Frequency

Voltage

6.0V

5.5V

4.5V

4.0V

2.0V

20 MHz

5.0V

3.5V

3.0V

2.5V

16 MHz

Frequency

Voltage

6.0V

5.5V

4.5V

4.0V

2.0V

5.0V

3.5V

3.0V

2.5V

FMAX = (12 MHz/V) (VDDAPPMIN – 2.5V) + 4 MHz

Note 1: VDDAPPMIN is the minimum voltage of the PICmicro® device in the application.

4 MHz 10 MHz

Note 2: FMAX has a maximum frequency of 10 MHz.

 2004 Microchip Technology Inc. DS39598E-page 119

PIC16F818/819

15.1 DC Characteri stics: Supply Voltage

PIC16F818/819 (Industrial, Extended)

PIC16LF818/819 (I ndustrial)

PIC16LF818/819

(Industrial) Stan dard Ope rating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

Stan dard Ope rating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

-40°C ≤ TA ≤ +125°C for extended

Param

No. Symbol Characteristic Min Typ Max Units Conditions

VDD Supply Volt ag e

D001 PIC16LF818/819 2.0 — 5.5 V HS, XT, RC and LP Oscillator mode

D001 PIC16F818/819 4.0 —5.5 V

D002 VDR RAM Data Retention

Voltage(1) 1.5 — — V

D003 VPOR VDD Start Vo ltage

to ensure internal

Power-on Reset signal

— — 0. 7 V See Section 12.4 “Power-on Reset (POR)”

for details

D004 SVDD VDD Rise Rate

to ensure internal

Power-on Reset signal

0.05 — — V/ms See Section 12.4 “Power-on Reset (POR)”

for details

VBOR Brown-out Reset Voltage

D005 PIC16LF818/819 3.65 — 4.35 V

D005 PIC16F818/819 3.65 —4.35 V FMAX = 14 MHz(2)

Legend: Shading of rows is to assist in readability of the table.

Note 1: This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM data

2: When BOR is enabled, the device will operate correctly until the VBOR voltage trip point is reached.

PIC16F818/819

DS39598E-page 120  2004 Microchip Technology Inc.

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Power-Down Current (IPD)(1)

PIC16LF818/819 0.1 0.4 µA -40°C VDD = 2.0V0.1 0.4 µA+25°C

0.4 1.5 µA+85°C

PIC16LF818/819 0.3 0.5 µA -40°C VDD = 3.0V0.3 0.5 µA+25°C

0.7 1.7 µA+85°C

All devices 0.6 1.0 µA -40°C

VDD = 5.0V

0.6 1.0 µA+25°C

1.2 5.0 µA+85°C

Extended devices 6.0 28 µA +125°C

Legend: Shading of rows is to assist in readability of the table.

Note 1: 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 or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

 2004 Microchip Technology Inc. DS39598E-page 121

PIC16F818/819

Supply Current (IDD)(2,3)

PIC16LF818/819 9 20 µA -40°C VDD = 2.0V

FOSC = 32 kHZ

(LP Oscillator)

715µA+25°C

715µA+85°C

PIC16LF818/819 16 30 µA -40°C VDD = 3.0V14 25 µA+25°C

14 25 µA+85°C

All devices 32 40 µA -40°C

VDD = 5.0V

26 35 µA+25°C

26 35 µA+85°C

Extended devices 35 53 µA +125°C

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial) (Continued)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Legend: Shading of rows is to assist in readability of the table.

Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is mea sured with

the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

PIC16F818/819

DS39598E-page 122  2004 Microchip Technology Inc.

Supply Current (IDD)(2,3)

PIC16LF818/819 72 95 µA -40°C VDD = 2.0V

FOSC = 1 MH Z

(RC Oscillator)(3)

76 90 µA+25°C

76 90 µA+85°C

PIC16LF818/819 138 175 µA -40°C VDD = 3.0V136 170 µA+25°C

136 170 µA+85°C

All devices 310 380 µA -40°C

VDD = 5.0V

290 360 µA+25°C

280 360 µA+85°C

Extended devices 350 500 µA +125°C

PIC16LF818/819 270 315 µA -40°C VDD = 2.0V

FOSC = 4 MHz

(RC Oscillator)(3)

280 310 µA+25°C

285 310 µA+85°C

PIC16LF818/819 460 610 µA -40°C VDD = 3.0V450 600 µA+25°C

450 600 µA+85°C

All devices 900 1060 µA -40°C

VDD = 5.0V

890 1050 µA+25°C

890 1050 µA+85°C

Extended devices .920 1.5 mA +125°C

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial) (Continued)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Legend: Shading of rows is to assist in readability of the table.

Note 1: 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 or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

 2004 Microchip Technology Inc. DS39598E-page 123

PIC16F818/819

Supply Current (IDD)(2,3)

All devices 1.8 2.3 mA -40°C VDD = 4.0V

FOSC = 20 MHZ

(HS Os cillator)

1.6 2.2 mA +25°C

1.3 2.2 mA +85°C

All devices 3.0 4.2 mA -40°C

VDD = 5.0V

2.5 4.0 mA +25°C

2.5 4.0 mA +85°C

Extended devices 3.0 5.0 mA +125°C

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial) (Continued)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Legend: Shading of rows is to assist in readability of the table.

Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is mea sured with

the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

PIC16F818/819

DS39598E-page 124  2004 Microchip Technology Inc.

Supply Current (IDD)(2,3)

PIC16LF818/819 8 20 µA -40°C VDD = 2.0V

FOSC = 31.25 kHz

(RC_RUN mode,

Internal RC Oscillator)

715µA+25°C

715µA+85°C

PIC16LF818/819 16 30 µA -40°C VDD = 3.0V14 25 µA+25°C

14 25 µA+85°C

All devices 32 40 µA -40°C

VDD = 5.0V

29 35 µA+25°C

29 35 µA+85°C

Extended devices 35 45 µA +125°C

PIC16LF818/819 132 160 µA -40°C VDD = 2.0V

FOSC = 1 MHz

(RC_RUN mode,

Internal RC Oscillator)

126 155 µA+25°C

126 155 µA+85°C

PIC16LF818/819 260 310 µA -40°C VDD = 3.0V230 300 µA+25°C

230 300 µA+85°C

All devices 560 690 µA -40°C

VDD = 5.0V

500 650 µA+25°C

500 650 µA+85°C

Extended devices 570 710 µA +125°C

PIC16LF818/819 310 420 µA -40°C VDD = 2.0V

FOSC = 4 MHz

(RC_RUN mode,

Internal RC Oscillator)

300 410 µA+25°C

300 410 µA+85°C

PIC16LF818/819 550 650 µA -40°C VDD = 3.0V530 620 µA+25°C

530 620 µA+85°C

All devices 1.2 1.5 mA -40°C

VDD = 5.0V

1.1 1.4 mA +25°C

1.1 1.4 mA +85°C

Extended devices 1.3 1.6 mA +125°C

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial) (Continued)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Legend: Shading of rows is to assist in readability of the table.

Note 1: 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 or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

 2004 Microchip Technology Inc. DS39598E-page 125

PIC16F818/819

Supply Current (IDD)(2,3)

PIC16LF818/819 .950 1.3 mA -40°C VDD = 3.0V

FOSC = 8 MHz

(RC_RUN mode,

Internal RC Oscillator)

.930 1.2 mA +25°C

.930 1.2 mA +85°C

All devices 1.8 3.0 mA -40°C

VDD = 5.0V

1.7 2.8 mA +25°C

1.7 2.8 mA +85°C

Extended devices 2.0 4.0 mA +125°C

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial) (Continued)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Legend: Shading of rows is to assist in readability of the table.

Note 1: The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is mea sured with

the part in Sleep mode, with all I/O pins in high-impedance state and tied to VDD or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

PIC16F818/819

DS39598E-page 126  2004 Microchip Technology Inc.

D022

(∆IWDT)Module Differential Currents (∆IWDT, ∆IBOR, ∆ILVD, ∆IOSCB, ∆IAD)

Wa tchdog Timer 1.5 3.8 µA -40°C VDD = 2.0V2.2 3.8 µA+25°C

2.7 4.0 µA+85°C

2.3 4.6 µA -40°C VDD = 3.0V2.7 4.6 µA+25°C

3.1 4.8 µA+85°C

3.0 10.0 µA -40°C

VDD = 5.0V

3.3 10.0 µA+25°C

3.9 13.0 µA+85°C

Extended Devices 5.0 21.0 µA +125°C

D022A

(∆IBOR)Brown-out Reset 40 60 µA-40°C to +85°CV

DD = 5.0V

D025

(∆IOSCB)Timer1 Oscillator 1.7 2.3 µA -40°C VDD = 2.0V

32 kHz on Timer1

1.8 2.3 µA+25°C

2.0 2.3 µA+85°C

2.2 3.8 µA -40°C VDD = 3.0V2.6 3.8 µA+25°C

2.9 3.8 µA+85°C

3.0 6.0 µA -40°C VDD = 5.0V3.2 6.0 µA+25°C

3.4 7.0 µA+85°C

D026

(∆IAD)A/D Converter 0.001 2.0 µA-40°C to +85°CV

DD = 2.0V

A/D on, Sleep, not converting

0.001 2.0 µA-40°C to +85°CV

DD = 3.0V

0.003 2.0 µA-40°C to +85°CVDD = 5.0V

Extended Devices 4.0 8.0 µA-40°C to +125°C

15.2 DC Characteri stics: Power-Down and Supply Current

PIC16F818/819 (I ndustrial, Extended)

PIC16LF818/819 (I ndustrial) (Continued)

PIC16LF818/819

(Industrial) Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819

(Industrial, Extended)

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 Typ Max Units Conditions

Legend: Shading of rows is to assist in readability of the table.

Note 1: 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 or VSS and all features that add delta

current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).

2: The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin loading

and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have an impact on

the current consumption.

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 enabled/disabled as specified.

3: For RC oscillator configurations, current through REXT is not included. The current t hrough the resistor can be estimated

by the formula Ir = VDD/2REXT (mA) with REXT in kΩ.

 2004 Microchip Technology Inc. DS39598E-page 127

PIC16F818/819

15.3 DC Characteristics: Internal RC Accuracy

PIC16F818/819, PIC16F818/ 819 TSL (Industrial , Extended)

PIC16LF818/819, PIC16LF818/ 819 TSL (Industrial)

PIC16LF818/819(3)

PIC16LF818/819 TSL(3)

(Industrial)

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

PIC16F818/819(3)

PIC16F818/819 TSL(3)

(Industrial, Extended)

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 Min Typ Max Units Conditions

INTOSC Accuracy @ Freq = 8 MHz, 4 MHz, 2 MHz, 1 MHz, 500 kHz, 250 kHz, 125 kHz(1)

PIC16LF818/819 -5 ±1 5 % +25°C VDD = 2.7-3.3V-25 — 25 % -10°C to +85°C

-30 — 30 % -40°C to +85°C

PIC16F818/819(4) -5 ±1 5 % +25°C

VDD = 4.5-5.5V

-25 —25 %-10°C to +85°C

-30 —30 %-40°C to +85°C

-35 —35 %-40°C to +125°C

PIC16L F 818/819 TSL -2 ±1 2 % +25°C VDD = 2.7-3.3V-5 — 5 % -10°C to +85°C

-10 — 10 % -40°C to +85°C

PIC16F818/819 TSL(5) -2 ±1 2 % +25°C

VDD = 4.5-5.5V

-5 — 5 % -10°C to +85°C

-10 —10 %-40°C to +85°C

-15 —15 %-40°C to +125°C

INTRC Accuracy @ Freq = 31 kHz(2)

PIC16LF818/819 26.562 — 35.938 kHz -40°C to +85°C VDD = 2.7-3.3V

PIC16F818/819(4) 26.562 —35.938 kHz -40°C to +85°C VDD = 4.5-5.5V

PIC16LF818/819 TSL 26.562 — 35.93 8 kHz -40°C to +85°C VDD = 2.7-3.3V

PIC16F818/819 TSL(5) 26.562 —35.938 kHz -40°C to +85°C VDD = 4.5-5.5V

Legend: Shading of rows is to assist in readability of the table.

Note 1: Frequency calibrated at 25°C. OSCTUNE register can be used to compensate for temperature drift.

2: INTRC frequency after calibration.

3: The only specification diff erence between a non-TSL device and a TSL device is t he int ernal RC oscillator specifications

listed above. All other specifications are maintained.

4: Example part number for the specifications listed above: PIC16F818-I/SS (PIC16F818 device, Industrial temperature,

SSOP package).

5: Example part number for the specifications listed above: PIC16F818-I/SSTSL (PIC16F818 device, Industrial

temperature, SSOP package).

PIC16F818/819

DS39598E-page 128  2004 Microchip Technology Inc.

15.4 DC Characteristics: PIC16F818/819 (Industrial, Extended)

PIC16LF818/819 (Industrial)

DC CHARACTERISTICS

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

-40°C ≤ TA ≤ +125°C for extended

Operating voltage VDD range as described in Section 15.1 “DC

Characteristics: Supply Voltage”.

Param

No. Sym Characteristic Min Typ† Max Units Conditions

VIL Input Low Voltage

I/O ports:

D030 with TTL buffer VSS — 0.15 VDD V For entire VDD rang e

D030A VSS —0.8V V4.5V ≤ VDD ≤ 5.5V

D031 with Schmitt Trigger buffer VSS —0.2 VDD V

D032 MCLR, OSC1 (in RC mode) VSS —0.2 VDD V(Note 1)

D033 OSC1 (in XT and LP mode) VSS —0.3V V

OSC1 (in HS mode) VSS —0.3 VDD V

Ports RB1 and RB4:

D034 with Schmitt Trigger buffer VSS —0.3 VDD V For entire VDD range

VIH Input High Voltage

I/O ports:

D040 with TTL buf fer 2.0 — VDD V4.5V ≤ VDD ≤ 5.5V

D040A 0.25 VDD + 0.8V — VDD V For entire VDD range

D041 with Schmitt Trigger buffer 0.8 VDD —VDD V For entire VDD range

D042 MCLR 0.8 VDD —VDD V

D042A OSC1 (in XT and LP mode) 1.6V — VDD V

OSC1 (in HS mode) 0.7 VDD —VDD V

D043 OSC1 (in RC mo de) 0.9 VDD —VDD V(Note 1)

Ports RB1 and RB4:

D044 with Schmitt Trigger buffer 0.7 VDD —VDD V For entire VDD range

D070 IPURB PORTB Weak Pull-up Current 50 250 400 µAVDD = 5V, VPIN = VSS

IIL Input Leak age Current (Notes 2, 3)

D060 I/O ports — — ± 1 µAVss ≤ VPIN ≤ VDD, pin at

high-impedance

D061 MCLR ——±5µAVss ≤ VPIN ≤ VDD

D063 OSC1 — — ±5 µAVss ≤ VPIN ≤ VDD, XT, HS

and LP oscillator

configuration

† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested .

Note 1: In RC oscil lator confi guration, the OSC1/CLKI pin is a Schmitt Trigger inpu t. It is not reco mmended that the

PIC16F818/819 be driven with external clock in RC mode.

2: The leakage current on the M CLR pin is strongly dependent on the applied voltage lev el. The specified leve ls

represent normal operating condi tions. Higher leaka ge current may be meas ured at different input volt ages .

3: Negative current is defined as current sourced by the pin.

 2004 Microchip Technology Inc. DS39598E-page 129

PIC16F818/819

VOL Output Low Voltage

D080 I/O ports — — 0.6 V IOL = 8.5 mA, VDD = 4.5V,

-40°C to +125°C

D083 OSC2/CLKO

(RC oscillator config) ——0.6VI

OL = 1.6 mA, VDD = 4.5V,

-40°C to +125°C

VOH Output High Voltage

D090 I/O ports (Note 3) VDD – 0.7 — — V IOH = -3.0 mA, VDD = 4.5V,

-40°C to +125°C

D092 OSC2/CLKO

(RC oscillator config) VDD – 0.7 — — V IOH = -1.3 mA, VDD = 4.5V,

-40°C to +125°C

Capacitive Loading Specs on Output Pins

D100 COSC2 OSC2 pin — — 15 pF In XT, HS and LP modes

when ex tern al c loc k is us ed

to drive OSC1

D101 CIO All I/O pins and OSC 2

(in RC mode) — — 50 pF

D102 CBSCL, SDA in I2C™ mode ——400pF

Data EEPROM Memory

D120 EDEndurance 100K

10K 1M

100K —

—E/W

E/W -40°C to +85°C

+85°C to +125°C

D121 VDRW VDD for read/write VMIN — 5.5 V Using EECON to read/write,

VMIN = min. operating

voltage

D122 TDEW Erase/wri te cycle time — 4 8 ms

Program Flash Memory

D130 EPEndurance 10K

1K 100K

10K —

—E/W

E/W -40°C to +85°C

+85°C to +125°C

D131 VPR VDD for read VMIN —5.5 V

D132A VDD for erase/write VMIN — 5.5 V Using EECON to read/write,

VMIN = min. operating

voltage

D133 TPE Erase cycle time — 2 4 ms

D134 TPW Write cycle time — 2 4 ms

15.4 DC Characteristics: PIC16F818/819 (Industrial, Extended)

PIC16LF818/819 (Industrial) (Continued)

DC CHARACTERISTICS

Standard Operating Conditions (unless otherwise stated)

Operating temperature -40°C ≤ TA ≤ +85°C for industrial

-40°C ≤ TA ≤ +125°C for extended

Operating voltage VDD range as described in Section 15.1 “DC

Characteristics: Supply Voltage”.

Param

No. Sym Characteristic Min Typ† Max Units Conditions

† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested .

Note 1: In RC oscil lator confi guration, the OSC1/CLKI pin is a Schmitt Trigger inpu t. It is not reco mmended that the

PIC16F818/819 be driven with external clock in RC mode.

2: The leakage current on the M CLR pin is strongly dependent on the applied voltage lev el. The specified leve ls

represent normal operating condi tions. Higher leaka ge current may be measu re d at dif ferent input v olt ages .

3: Negative current is defined as current sourced by the pin.

PIC16F818/819

DS39598E-page 130  2004 Microchip Technology Inc.

15.5 Timing Parameter Symbology

The timing parameter symbols have been created

using one of the following formats:

FIGURE 15-3: LOAD CONDITIONS

1. TppS2ppS 3. TCC:ST (I2C specifications only)

2. TppS 4. Ts (I2C specifications only)

TF Frequency T Time

Lowercase letters (pp) and their meanings:

cc CCP1 osc OSC1

ck CLKO rd RD

cs CS rw RD or WR

di SDI sc SCK

do SDO ss SS

dt Data in t0 T0CKI

io I/O port t1 T1CKI

mc MCLR wr WR

Uppe rcase letters and their meanings :

SFFall PPeriod

HHigh RRise

I Invalid (High-impedance) V Valid

L Low Z High-impedance

I2C only

AA output access High High

BUF Bus free Low Low

TCC:ST (I2C specifications only)

HD Hold SU Setup

DAT DATA input hold STO Stop condition

STA Start condition

VDD/2

Pin Pin

VSS VSS

RL= 464Ω

CL= 50 pF for all pins except OSC2, but including PORTD and PORTE outputs as ports

15 pF for OSC2 output

Load Condition 1 Load Condition 2

 2004 Microchip Technology Inc. DS39598E-page 131

PIC16F818/819

FIGURE 15-4: EXTERNAL CLOCK TIMING

OSC1

CLKO

Q4 Q1 Q2 Q3 Q4 Q1

23344

TABLE 15-1: EXTERNAL CLOCK TIMING REQUIREMENTS

Param

No. Sym Characteristic Min Typ† Max Units Conditions

FOSC External CLKI Frequ ency (Note 1) DC — 1 MHz XT and RC Oscillator mode

DC — 20 MHz HS Oscillator mode

DC — 32 kHz LP Oscillator mode

Oscillator Frequency (Note 1) DC — 4 MHz RC Oscillato r mode

0.1 — 4 MHz XT Oscill ator mode

5—

—20

200 MHz

kHz HS Oscillator mode

LP Oscillator mode

OSC External CLKI Perio d (Note 1) 1000 — — ns XT and RC Oscillator mode

50 — — ns HS Oscillator mode

5 — — ms LP Oscillator mode

Oscillator Period (Note 1) 250 — — ns RC Oscillator mode

250 — 10,000 ns XT Oscillator mode

50 — 250 ns HS Oscillator mode

5 — — ms LP Oscillator mode

CY Instruction Cycle Time (Note 1) 200 TCY DC ns TCY = 4/FOSC

3TOSL,

TOSHExtern al C lock in (OSC 1 ) High

or Low Time 500 — — ns XT Oscillator

2.5 — — ms LP Oscillator

15 — — ns HS Oscillator

OSR,

TOSFExtern al C lock in (OSC 1 ) Rise or

Fall Time — — 25 ns XT Oscillator

— — 50 ns LP Oscillator

— — 15 ns HS Oscillator

† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested .

Note 1: Instruct ion 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/CLKI pin. When an external clock input is used, the

“max.” cycle time limit is “DC” (no clock) for all devices.

PIC16F818/819

DS39598E-page 132  2004 Microchip Technology Inc.

FIGURE 15-5: CLKO AND I/O TIMING

TABLE 15-2: CLKO AND I/O TIMING REQUIREMENTS

Note: Refer to Figure 15-3 for load conditions.

OSC1

CLKO

I/O pin

(Input)

I/O pin

(Output)

Q4 Q1 Q2 Q3

13 14

20, 21

19 18

12 16

Old Value New Value

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

10* TOSH2CKLOSC1 ↑ to CL KO ↓ — 75 200 ns (Note 1)

11* TOSH2CKHOSC1 ↑ to CLKO ↑ — 75 200 ns (Note 1)

12* TCKR CLKO Rise Time — 35 100 ns (Note 1)

13* TCKF CLK O Fall Time — 35 100 ns (Note 1)

14* TCKL2IOVCLKO ↓ to Port Out Valid — — 0.5 TCY + 20 ns (Note 1)

15* TIOV2CKH Port In Valid before CLKO ↑ TOSC + 200 — — ns (Note 1)

16* TCKH2IOI Por t In H o l d af te r CLK O ↑ 0——ns(Note 1)

17* TOSH2IOVOSC1 ↑ (Q1 cycle) to Port Out Valid — 100 255 ns

18* TOSH2IOIOSC1 ↑ (Q2 cycle) to Port

Input Invalid (I/O in hold time) PIC16F818/819 100 — — ns

PIC16LF818/819 200 — — ns

19* TIOV2OSH Port Input Valid to OSC1 ↑ (I/O in setup time) 0 — — ns

20* TIOR Port Output Rise Time PIC16F818/819 — 10 40 ns

PIC16LF818/819 — — 145 ns

21* TIOF Port Output Fall Time PIC16F818/819 — 10 40 ns

PIC16LF818/819 — — 145 ns

22††* TINP INT pin High or Low Time TCY ——ns

23††* TRBP RB7:RB4 Change INT High or Low Time TCY ——ns

* Thes e parameters are characterized but not tested.

† Data in “T yp” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not

tested.

†† Thes e parameters are async hronous events, not related to any internal clock edges.

Note 1: M easur ements are taken in RC mode, where CLKO output is 4 x TOSC.

 2004 Microchip Technology Inc. DS39598E-page 133

PIC16F818/819

FIGURE 15-6: RESET, WATCHDOG T IMER, OSCILLATOR START-UP TIMER AND

POWER-UP TIMER TIMING

FIGURE 15-7: BROWN-OUT RESET TIMING

TABLE 15-3: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER

AND BROWN-OUT RESET REQUIREMENTS

VDD

MCLR

Internal

POR

PWRT

Time-out

Oscillator

Time-out

Internal

Reset

Watchdog

Timer

Reset

I/O pins

Note: Refer to Figure 15-3 for load conditions.

VDD VBOR

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

30 TMCLMCLR Pu lse Width (Low) 2 — — µsVDD = 5V, -40°C to +85°C

31* TWDT Watchdog Timer T ime-out Period

(no prescaler) 13.6 16 18.4 ms VDD = 5V, -40°C to +85°C

32 TOST Oscillation Start-up Timer Period — 1024 TOSC ——TOSC = OSC1 period

33* TPWRT Power-up Timer Period 61.2 72 82.8 ms VDD = 5V, -40°C to +85°C

34 TIOZ I/O High-Impedance from MCLR

Low or Watchdog Timer Reset ——2.1µs

35 TBOR Bro wn-out Rese t Pulse Width 100 — — µsVDD ≤ VBOR (D005)

* Thes e parameters are characterized but not tested.

† Data in “T yp” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not

tested.

PIC16F818/819

DS39598E-page 134  2004 Microchip Technology Inc.

FIGURE 15-8: TIMER0 AND TIME R1 EXTERNAL CLOCK TIMINGS

TABLE 15-4: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

40* TT0H T0CKI High Pulse Width No Prescaler 0.5 TCY + 20 — — ns Must also meet

parameter 42

With Prescaler 10 — — ns

41* TT0L T0CKI Low Pulse Width No Prescaler 0.5 TCY + 20 — — ns Must also meet

parameter 42

With Prescaler 10 — — ns

42* TT0P T0CKI Period No Prescaler TCY + 40 ——ns

With Prescaler Greater of:

20 or TCY + 40

— — ns N = prescale value

(2, 4, ..., 256)

45* TT1H T1CKI High

Time Synchronous , Prescaler = 1 0.5 TCY + 20 — — ns Must also meet

parameter 47

Synchronous,

Prescaler = 2,4,8 PIC16F818/819 15 — — ns

PIC16LF818/819 25 — — ns

Asynchronous PIC16F818/819 30 — — ns

PIC16LF818/819 50 — — ns

46* TT1L T1CKI Low Time Synchronous, Prescaler = 1 0.5 TCY + 20 — — ns Must also meet

parameter 47

Synchronous,

Prescaler = 2,4,8 PIC16F818/819 15 — — ns

PIC16LF818/819 25 — — ns

Asynchronous PIC16F818/819 30 — — ns

PIC16LF818/819 50 — — ns

47* TT1P T1CK I Input

Period Synchronous PIC16F818/81 9 Greater of:

30 or TCY + 40

— — ns N = prescale

value (1, 2, 4, 8)

PIC16LF81 8/ 819 Greater of:

50 or TCY + 40

N = prescale

value (1, 2, 4, 8)

Asynchronous PIC16F818/819 60 — — ns

PIC16LF818/819 100 — — ns

FT1 Timer1 Oscillator Input Frequency Range

(Oscillator enabled by setting bit T1OSCEN) DC — 32.768 kHz

48 TCKEZTMR1 Delay from External Clock Edge to Timer Increment 2 TOSC —7 TOSC —

* Thes e parameters are charact erized but not tested.

† Data in “T yp” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested.

Note: Refer to Figure 15-3 for load conditions.

RA4/T0CKI

RB6/T1OSO/T1CKI

TMR0 or TMR1

 2004 Microchip Technology Inc. DS39598E-page 135

PIC16F818/819

FIGURE 15-9: CAPTURE/COMPARE/PWM TIMINGS (CCP1)

TABLE 15-5: CAPTURE/COMPARE/PWM REQUIREMENTS (CCP1)

Note: Refer to Figure 15-3 for load conditions.

CCP1

(Capture Mode)

50 51

53 54

CCP1

(Compare or PWM Mode )

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

50* TCCL CCP1

Input Low Time No Prescaler 0.5 TCY + 20 — — ns

PIC16F818/819 10 — — ns

With Prescaler PIC16LF818/819 20 — — ns

51* TCCH CCP1

Input High

Time

No Prescaler 0.5 TCY + 20 — — ns

PIC16F818/819 10 — — ns

With Prescaler PIC16LF818/819 20 — — ns

52* TCCP CCP1 Input Peri od 3 TCY + 40

N— — ns N = prescale

value (1 ,4 o r 16)

53* TCCR CCP1 Output Rise Time PIC16F818/819 — 10 25 ns

PIC16LF818/819 — 25 50 ns

54* TCCF CCP1 Out put F all Time PIC16F818/819 — 10 25 ns

PIC16LF818/819 — 25 45 ns

* These parameters are characterized but not tested.

† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance

only and are not tested .

PIC16F818/819

DS39598E-page 136  2004 Microchip Technology Inc.

FIGURE 15-10: SPI™ MASTER MODE TIMING (CKE = 0, SMP = 0)

FIGURE 15-11: SPI™ MASTER MODE TIMING (CKE = 1, SMP = 1)

SCK

(CKP = 0)

SCK

(CKP = 1)

SDO

SDI

71 72

73 74

75, 76

MSb LSb

Bit 6 - - - - - -1

LSb In

Bit 6 - - - -1

Note: Refer to Figure 15-3 for load conditions.

MSb In

SCK

(CKP = 0)

SCK

(CKP = 1)

SDO

SDI

71 72

75, 76

MSb

MSb In

Bit 6 - - - - - -1

LSb In

Bit 6 - - - -1

LSb

Note: Refer to Figure 15-3 for load conditions.

 2004 Microchip Technology Inc. DS39598E-page 137

PIC16F818/819

FIGURE 15-12: SPI™ SLAVE MODE TIMING (CKE = 0)

FIGURE 15-13: SPI™ SLAVE MODE TIMING (CKE = 1)

SCK

(CKP = 0)

SCK

(CKP = 1)

SDO

SDI

71 72

73 74

75, 76 77

MSb LSb

Bit 6 - - - - - -1

Bit 6 - - - -1 LS b In

Note: Refer to Figure 15-3 for load conditions.

MSb In

SCK

(CKP = 0)

SCK

(CKP = 1)

SDO

SDI

71 72

SDI

75, 76

MSb Bit 6 - - - - - -1 LSb

Bit 6 - - - -1 LSb In

Note: Refer to Figure 15-3 for load conditions.

MSb In

PIC16F818/819

DS39598E-page 138  2004 Microchip Technology Inc.

TA BLE 15-6: SPI™ MODE REQUIREMENTS

FIGURE 15-14 : I2C™ BUS STAR T/STOP BITS TIMING

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

70* TSSL2SCH,

TSSL2SCLSS ↓ to SCK ↓ or SCK ↑ Input TCY ——ns

71* TSCH SCK Input High Time (Slave mode) TCY + 20 — — ns

72* TSCL SCK Input Low Time (Slave mode) TCY + 20 — — ns

73* TDIV2SCH,

TDIV2SCLSetup T ime of SDI Data Input to SCK Edge 100 — — ns

74* TSCH2DIL,

TSCL2DILHold Ti me of SDI Data Input to SCK Edge 100 — — ns

75* TDOR SDO Data Output Rise Time PIC16F818/819

PIC16LF818/819 —

—10

25 25

50 ns

76* TDOF SDO Data Output Fall Time — 10 25 ns

77* TSSH2DOZSS ↑ to SDO Output High-Impedance 10 — 50 ns

78* TSCR SCK Output Rise Time

(Master mode) PIC16F818/819

PIC16LF818/819 —

—10

25 25

50 ns

79* TSCF SCK Output Fall Time (Master mode) — 10 25 ns

80* TSCH2DOV,

TSCL2DOVSDO Data Output Valid after SCK

Edge PIC16F818/819

PIC16LF818/819 —

——

—50

145 ns

81* TDOV2SCH,

TDOV2SCLSDO Data Output Setup to SCK Edge TCY ——ns

82* TSSL2DOV SDO Data Output Valid after SS ↓ Edge — — 50 ns

83* TSCH2SSH,

TSCL2SSHSS ↑ af ter SCK Edge 1.5 TCY + 40 — — ns

* Thes e parameters are characterized but not tested.

† Data i n “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are not

tested.

Note: Refer to Figure 15-3 for load conditions.

SCL

SDA

Start

Condition Stop

Condition

 2004 Microchip Technology Inc. DS39598E-page 139

PIC16F818/819

TABLE 15-7: I2C™ BUS START/STOP BITS REQUIREMENTS

FIGURE 15-15 : I2C™ BUS DATA TIMING

Param

No. Symbol Characteristic Min Typ Max Units Conditions

90* TSU:STA Start Condition 100 kHz mode 4700 — — ns Only relevant for Repeated

Start condition

Setu p Time 400 kHz mode 600 — —

91* THD:STA S tart Condition 100 kHz mode 4000 — — ns After this period , the first clock

pulse is generated

Hold Time 400 kHz mode 600 — —

92* TSU:STO Stop Condition 100 kHz mode 4700 — — ns

Setu p Time 400 kHz mode 600 — —

93 THD:STO Stop Condition 100 kHz mode 4000 — — ns

Hold Time 400 kHz mode 600 — —

* These parameters are characterized but not tested.

Note: Refer to Figure 15-3 for load conditions.

91 92

100 101

103

106 107

109 109 110

102

SCL

SDA

Out

PIC16F818/819

DS39598E-page 140  2004 Microchip Technology Inc.

TABLE 15-8: I2C™ BUS DATA REQUIREMENTS

Param.

No. Symbol Characteristic Min Max Units Conditions

100* THIGH Clock High Time 100 kHz mode 4.0 — µs

400 kHz mode 0.6 — µs

SSP Module 1.5 TCY —

101* TLOW Clock Low Time 100 kHz mode 4.7 — µs

400 kHz mode 1.3 — µs

SSP Module 1.5 TCY —

102* TRSDA and SCL Rise

Time 100 kHz mode — 1000 ns

400 kHz mode 20 + 0.1 CB300 ns CB is specified to be from

10-400 pF

103* TFSDA and SCL Fall

Time 100 kHz mode — 300 ns

400 kHz mode 20 + 0.1 CB300 ns CB is specified to be from

10-400 pF

90* TSU:STA Start Condition

Setup Time 100 kHz mode 4.7 — µs Only releva nt for Re peated

Start condit ion

400 kHz mode 0.6 — µs

91* THD:STA S tart Condition Hold

Time 100 kHz mode 4.0 — µs After this period, the first

clo ck pulse is gene rated

400 kHz mode 0.6 — µs

106* THD:DAT Data Input Hold

Time 100 kHz mode 0 — ns

400 kHz mode 0 0.9 µs

107* TSU:DAT Data Input Setup

Time 100 kHz mode 250 — ns (Note 2)

400 kHz mode 100 — ns

92* TSU:STO St op Co nd itio n

Setup Time 100 kHz mode 4.7 — µs

400 kHz mode 0.6 — µs

109* TAA Output Valid from

Clock 100 kHz mode — 3500 ns (Note 1)

400 kHz mode — — ns

110* TBUF Bus Free Time 100 kHz mode 4.7 — µs Time the bus must be free

before a new transmission

can start

400 kHz mode 1.3 — µs

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 SCL 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 sy stem but

the requireme nt, TSU:DAT ≥ 2 50 ns , must then b e met. Thi s will autom atical ly be the ca se if the de vice doe s

not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL

signal, it must output the next data bit to the SDA line, TR max. + TSU:DAT = 1000 + 250 = 1250 ns

(according to the Standard mode I2C bus specification), before the SCL line is released.

 2004 Microchip Technology Inc. DS39598E-page 141

PIC16F818/819

TABLE 15-9: A/D CONVERTER CHARACTERISTICS: PIC16F818/819 (INDUSTRIAL, EXTENDED)

PIC16LF818/819 (INDUSTRIAL)

Param

No. Sym Characteristic Min Typ† Max Units Conditions

A01 NRResolution — — 10-bits bit VREF = VDD = 5.12V,

VSS ≤ VAIN ≤ VREF

A03 EIL Integral Linearity Error — — <±1 LSb VREF = VDD = 5.12V,

VSS ≤ VAIN ≤ VREF

A04 EDL Differential Linearity Error — — <±1 LSb VREF = VDD = 5.12V,

VSS ≤ VAIN ≤ VREF

A06 EOFF Offset Er ror — — <± 2 LSb VREF = VDD = 5.12V,

VSS ≤ VAIN ≤ VREF

A07 EGN Gain Error — — <±1 LSb VREF = VDD = 5.12V,

VSS ≤ VAIN ≤ VREF

A10 — Monotonicity — guaranteed(3) ——VSS ≤ VAIN ≤ VREF

A20 VREF Reference Voltage (VREF+ – VREF-) 2.0 — VDD + 0.3 V

A21 VREF+ Reference Voltage High AVDD – 2.5V AVDD + 0.3V V

A22 VREF- Reference Voltage Low AVSS – 0.3V VREF+ – 2. 0V V

A25 VAIN Analog Input Voltage VSS – 0.3V — VREF + 0.3V V

A30 ZAIN Recommended Impedance of

Analog V oltage Source ——2.5kΩ(Note 4)

A40 IAD A/D Conversion

Current (VDD)PIC16F818/819 — 220 — µA Average current

consumption when A/D is on

(Not e 1)

PIC16LF818/819 — 90 — µA

A50 IREF VREF Input Current (Note 2) —

—

150

µA

During VAIN acquisition.

Based on differential of VHOLD

to VAIN to charge CHOLD,

see Section 11.1 “A/D

Acquisition Requirements”.

During A/D conversion cycle

† Dat a in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are

no t te sted.

Note 1: When A/D is off, it will not consume any current other than minor leakage current. The power-down current spec includes

any such leakage from the A/D module.

2: VREF current is from RA3 pin or VDD pin, whichever is selected as reference input.

3: The A/D conversion result never decreases with an increase in the input voltage and has no missing codes.

4: Maximum allowed impedance for analog voltage source is 10 kΩ. This requires higher acquisition time.

PIC16F818/819

DS39598E-page 142  2004 Microchip Technology Inc.

FIGURE 15-16: A/D CONVERSION TIMING

TABLE 15-10: A/D CONVERSION REQUIREMENTS

131

130

132

BSF ADCON0, GO

A/D CLK

A/D DATA

ADRES

ADIF

SAMPLE

OLD_DATA

Sampling Stopped

DONE

NEW_DATA

(TOSC/2)(1)

987 210

Note: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock start s. This allows the SLEEP

instruction to be executed.

1 TCY

. . . . . .

Param

No. Symbol Characteristic Min Typ† Max Units Conditions

130 TAD A /D Clock Period PIC16F818/819 1.6 — — µsTOSC based, VREF ≥ 3.0V

PIC16LF818/819 3.0 — — µsT

OSC based, VREF ≥ 2.0V

PIC16F818/819 2.0 4.0 6.0 µs A/D RC mode

PIC16LF818/819 3.0 6.0 9.0 µs A/D RC mode

131 TCNV Conversion Time (not including S/H time)

(Note 1) —12TAD

132 TACQ Acquisition Time (Note 2)

10*

—

µs

µs The minimum time is the

amplifier settling time. This may

be used if the “new” input

voltage has not changed by

more than 1 LSb (i.e., 5.0 mV @

5.12V) from the last sampled

voltage (as stated on CHOLD).

134 TGO Q4 to A/D Clock Start — TOSC/2 § — — 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.

* Thes e parameters are characterized but not tested.

† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are

no t te sted.

§ This specification ensured by design.

Note 1: A DRE S register may be read on the following TCY cycle.

2: See Section 11.1 “A/D Acquisition Requirements” for minimum conditions.

 2004 Microchip Technology Inc. DS39598E-page 143

PIC16F818/819

16.0 DC AND AC CHARACTERISTICS GRAPHS AND TABLES

“T ypical” represents the mean of the distribution at 25°C. “Maximum” or “minimum” represent s (mean + 3σ) or (mean – 3σ)

respectively, where σ is a standard deviation, over th e whole temperature range .

FIGURE 16-1: TYPICAL IDD vs. FOSC OVER VDD (HS MODE)

FIGURE 16-2: MAXIMUM IDD vs. FOSC OVER VDD (HS MODE)

Note: The g r ap hs and t ables p r ov ide d f oll ow in g th is no te a r e a s t ati sti ca l s um ma ry based on a limite d n um ber of

samples and are provided for informational purposes only. The performance characteristics listed herein

are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified

operating range (e.g., outside specified power supply range) and therefore, outside the warranted range.

4 6 8 10 12 14 16 18 20

FOSC (MHz)

IDD (mA)

2.0V

2.5V

3.0V

3.5V

4.0V

4.5V

5.0V

5.5V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

4 6 8 10 12 14 16 18 20

FOSC (MHz)

IDD (mA)

2.0V

2.5V

3.0V

3.5V

4.0V

4.5V

5.0V

5.5V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F818/819

DS39598E-page 144  2004 Microchip Technology Inc.

FIGURE 16-3: TYPICAL IDD vs. FOSC OVER VDD (XT MODE)

FIGURE 16-4: MAXIMUM IDD vs. FOSC OVER VDD (XT MODE)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 500 1000 1500 2000 2500 3000 3500 4000

FOSC (MHz)

IDD (mA)

2.0V

2.5V

3.0V

3.5V

4.0V

4.5V

5.0V

5.5V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

0 500 1000 1500 2000 2500 3000 3500 4000

FOSC (MHz)

IDD (mA)

2.0V

2.5V

3.0V

3.5V

4.0V

4.5V

5.0V

5.5V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

 2004 Microchip Technology Inc. DS39598E-page 145

PIC16F818/819

FIGURE 16-5: TYPICAL IDD vs. FOSC OVER VDD (LP MODE)

FIGURE 16-6: MAXIMUM IDD vs. FOSC OVER VDD (LP MODE)

20 30 40 50 60 70 80 90 100

FOSC (kHz)

IDD (uA)

2.0V

2.5V

3.0V

3.5V

4.0V

4.5V

5.0V

5.5V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

100

120

20 30 40 50 60 70 80 90 100

FOSC (kHz)

IDD (uA)

2.0V

2.5V

3.0V

3.5V

4.0V

4.5V

5.0V

5.5V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F818/819

DS39598E-page 146  2004 Microchip Technology Inc.

FIGURE 16-7: TYPICAL IDD vs. VDD, -40°C TO +125°C, 1 MHz TO 8 MHz

(RC_RUN MODE, ALL PERIPHERALS DISABLED)

FIGURE 16-8: MAXIMUM IDD vs. VDD, -40°C TO +125°C, 1 MHz TO 8 MHz

(RC_RUN MODE, ALL PERIPHERALS DISABLED)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.02.03.04.05.06.07.08.0

FOSC (MHz)

IDD (mA)

5.5V

5.0V

4.5V

4.0V

3.5V

3.0V

2.5V

2.0V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

1.02.03.04.05.06.07.08.0

FOSC (MHz)

IDD (mA)

5.5V

5.0V

4.5V

4.0V

3.5V

3.0V

2.5V

2.0V

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

 2004 Microchip Technology Inc. DS39598E-page 147

PIC16F818/819

FIGURE 16-9: IPD vs. VDD, -40°C TO +125°C (SLEEP MODE, ALL PERIPHERALS DISABLED)

FIGURE 16 - 10: AVERAGE FOSC vs. VDD FOR V ARIOUS VALUES OF R (RC MODE, C = 20 pF, +25°C)

0.001

0.01

0.1

100

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

IPD (uA)

Typ (25°C)

Max ( 85°C)

Max (125°C)

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

Freq (MHz)

100 k O hm

10 kOhm

5.1 kO hm

Operation above 4 MHz is no t r ecom mended

PIC16F818/819

DS39598E-page 148  2004 Microchip Technology Inc.

FIGURE 16-11: AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R

(RC MODE, C = 100 pF, +25°C)

FIGURE 16-12: AVERAGE FOSC vs. VDD FOR VARIOUS VALUES OF R

(RC MODE, C = 300 pF, +25°C)

0.0

0.5

1.0

1.5

2.0

2.5

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

Freq (MHz)

100 k O hm

10 kOhm

5.1 kOhm

3.3 kOhm

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

Freq (MHz)

100 kOhm

10 kOhm

5.1 kOhm

3.3 kOhm

 2004 Microchip Technology Inc. DS39598E-page 149

PIC16F818/819

FIGURE 16-13 : ∆IPD TIMER1 OSCILLATOR, -10°C TO +70°C (SLEEP MODE,

TMR1 COUNTER DISABLED)

FIGURE 16-14 : ∆IPD WDT, -40°C TO +125°C (SLEEP MODE, ALL PERIPHERALS DISABLED)

IPD Timer1 Oscillator, -10°C to +70°C SLEEP mode, TMR1 counter disabled

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

IPD (µA)

Typ (+25°C)

Max (-10°C to +70°C )

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

∆IWDT (µA)

Max (-40°C to +125°C)

Max (-40°C to +85 ° C)

Typ (2 5° C )

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F818/819

DS39598E-page 150  2004 Microchip Technology Inc.

FIGURE 16-15 : ∆IPD BOR vs. VDD, -4 0° C TO +12 5 °C (SLEEP MO D E,

BOR ENABLED AT 2.00V-2.16V)

FIGURE 16-16 : IPD A/D, -40°C TO +125°C, SLEEP MODE, A/D ENABLED (NOT CONVERTING)

100

1,000

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

IDD (µA)

Device in

Reset

Device in

Sleep

Indeterminant

State

Max (125°C)

Typ (25°C )

Max (125°C)

Typ (25°C)

Typical: statistical mean @ 25°C

Maxi mum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

Note: Device current in Reset

depends on oscillator mode,

frequency and circuit.

2.02.53.03.54.04.55.05.5

VDD (V)

∆IPD (µA)

Max

(-40°C t o +125°C)

Max

(-40°C to +85°C)

Typ (+25°C)

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

 2004 Microchip Technology Inc. DS39598E-page 151

PIC16F818/819

FIGURE 16-17: TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 5V, -40°C TO +125°C)

FIGURE 16-18: TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 3V, -40°C TO +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

0 5 10 15 20 25

IOH (-mA)

VOH (V)

Max

Ty p ( 25 °C)

Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 5 10 15 20 25

IOH (-mA)

VOH (V)

Max

Typ (25°C )

Min

Typical: statistical mean @ 25°C

Maximu m: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F818/819

DS39598E-page 152  2004 Microchip Technology Inc.

FIGURE 16-19: TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 5V, -40°C TO +125°C)

FIGURE 16-20: TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 3V, -40°C TO +125°C)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0 5 10 15 20 25

IOL (-mA)

VOL (V)

Max (125°C)

Max ( 85°C)

Ty p ( 25 °C)

Min (-40°C)

Typical: statistical mean @ 25°C

Maxi mum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20 25

IOL (-mA)

VOL (V)

Max (125°C)

Max (85°C)

Typ (25°C)

Min (-40°C)

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimu m: mean – 3σ (-40°C to +125°C)

 2004 Microchip Technology Inc. DS39598E-page 153

PIC16F818/819

FIGURE 16-21: MINIMUM AND MAXIMUM VIN vs. VDD (TTL INPUT, -40°C TO +125°C)

FIGURE 16-22: MINIMUM AND MAXIMUM VIN vs. VDD (ST INPUT, -40°C TO +125°C)

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

2.02.53.03.54.04.55.05.5

VDD (V)

VIN (V)

VTH Max (-40°C)

VTH Min (125°C)

VTH Typ (25°C)

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimu m: mean – 3σ (-40°C to +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

VIN (V)

VIH Max (125°C)

VIH Min (-40°C)

VIL Max (-40°C)

VIL Min (125°C)

Typical: statistical mean @ 25°C

Maximu m: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

PIC16F818/819

DS39598E-page 154  2004 Microchip Technology Inc.

FIGURE 16-23: MINIMUM AND MAXIMUM VIN vs. VDD (I2C™ INPUT, -40°C TO +125°C)

FIGURE 16-24: A/D NONLINEARITY vs. VREFH (VDD = VREFH, -40°C TO +125°C)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5

VDD (V)

VIN (V)

VIH Max

VIH Min

VILMax

VIL Min

Typical: statistical mean @ 25°C

Maximum: mean + 3σ (-40°C to +125°C)

Minimum: mean – 3σ (-40°C to +125°C)

VIL Max

0.5

1.5

2.5

3.5

22.533.544.555.5

VDD and VREFH (V)

Differential or Integral Nonlinearity (LSB)

-40C

25C

85C

125C

-40°C

+25°C

+85°C

+125°C

 2004 Microchip Technology Inc. DS39598E-page 155

PIC16F818/819

FIGURE 16-25: A/D NONLINEARITY vs. VREFH (VDD = 5V, -40°C TO +125°C)

0.5

1.5

2.5

22.533.544.555.5

VREFH (V)

Differential or Integral Nonlinearilty (LSB)

Max (-40C to 125C)

Typ (25C)

Typ (+25 °C)

Max (-40°C to +125°C)

PIC16F818/819

DS39598E-page 156  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 157

PIC16F818/819

17.0 PACKAGING INFORMATION

17.1 Package Marking Information

18-Lead PDIP

XXXXXXXXXXXXXXXXX

YYWWNNN

Example

PIC16F818-I/P

0410017

18-Lead SOIC

XXXXXXXXXXXX

YYWWNNN

Example

PIC16F818-04

/SO 0410017

20-Lead SSOP

XXXXXXXXXXX

YYWWNNN

Example

PIC16F818-

20/SS

0410017

28-Lead QFN

XXXXXXXX

YYWWNNN

Example

16F818-

I/ML

0410017

Legend: XX...X Customer specific inform at ion*

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

Note: In the event the ful l Micro chip pa rt num ber can not be ma rked on one line , it will

be carried ov er to the ne xt line thus lim it ing t he nu mb er of a vai la ble cha rac ters

for customer specific 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.

PIC16F818/819

DS39598E-page 158  2004 Microchip Technology Inc.

18-Lead Plastic Dual In-line (P) – 300 mil Body (PDIP)

1510515105

Mold Draft Angle Bottom 1510515105

Mold Draft Angle Top 10.929.407.87.430.370.310eBOverall Row Spacing § 0.560.460.36.022.018.014BLower Lead Width 1.781.461.14.070.058.045B1Upper Lead Width 0.380.290.20.015.012.008

Lead Thicknes s 3.433.303.18.135.130.125LTip to Seating Plane 22.9922.8022.61.905.898.890DOverall Length 6.606.356.10.260.250.240E1Molded Packag e Width 8.267.947.62.325.313.300EShoulder to Shoulder Width 0.38.015A1Base to Seating Plane 3.683.302.92.145.130.115A2Molded Package Thick ness 4.323.943.56.170.155.140ATop to Seating Plane 2.54.100

Pitch 1818

Number of Pins MAXNOMMINMAXNOMMINDimension Limits MILLIMETERSINCHES*Units

* Controlling Parameter

Notes:

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed

.010” (0.254mm) per side.

JEDEC Equivalent: MS-001

Drawing No. C04-007

§ Significant Characteristic

 2004 Microchip Technology Inc. DS39598E-page 159

PIC16F818/819

18-Lead Plasti c Small Outline (SO) – Wide, 300 mil Body (SOIC)

Foot A ngle φ048048

1512015120

Mold Draft Angle Bottom 1512015120

Mold Draft Angle Top 0.510.420.36.020.017.014BLead Width 0.300.270.23.012.011.009

Lead Thicknes s

1.270.840.41.050.033.016LFoot Le ngth 0.740.500.25.029.020.010hChamfer Distance 11.7311.5311.33.462.454.446DOverall Length 7.597.497.39.299.295.291E1Mold ed Packag e Width 10.6710.3410.01.420.407.394EOverall Width 0.300.200.10.012.008.004A1Standoff § 2.392.312.24.094.091.088A2Molded Package Thick ness 2.642.502.36.104.099.093AOverall Height 1.27.050

Pitch 1818

Number of Pins MAXNOMMINMAXNOMMINDimension Limits MILLIMETERSINCHES*Units

45°

* Controlling Parameter

Notes:

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed

.010” (0.254mm) per side.

JEDEC Equivalent: MS-013

Drawing No. C04-051

§ Significant Characteristic

PIC16F818/819

DS39598E-page 160  2004 Microchip Technology Inc.

20-Lead Plasti c Shrink Small Outline (SS) – 209 mil Body, 5.30 mm (SSOP)

0.38-0.22.015-.009BLead Width

8°4°0°8°4°0°

Foot Angle

0.25-0.09.010-.004

Lead Thickness

0.950.750.55.037.030.022LFoot Length

7.507.20.295.289.283.272DOverall Length

5.605.305.00.220.209.197E1Molded Package Width

8.207.807.40.323.307.291EOverall Width

--0.05--.002A1Standoff

1.851.751.65.073.069.065A2Molded Package Thickness

2.00--.079--AOverall Height

0.65.026

Pitch

2020

Number of Pins

MAXNOMMINMAXNOMMINDimension Limits

MILLIMETERS*INCHESUnits

shall not exceed .010" (0.254mm) per side.

Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions

Notes:

JEDEC Equivalent: MO-150

Drawing No. C04-072

*Controlling Parameter

Revised 11/03/03

 2004 Microchip Technology Inc. DS39598E-page 161

PIC16F818/819

28-Lead Plasti c Quad Flat No Lead Package (ML) 6x6 mm Body (QFN) –

With 0.55 mm Contact Length (Saw Singulated)

Contact Width

*Controlling Parameter

Drawing No. C04-105

Notes:

JEDEC equivalent: MO-220

b .009 .011 .013 0.23 0.28 0.33

Pitch

Number of Pins

Overall Width

Standoff

Overall Length

Overall Height

MAX

Units

Dimension Limits

.000

INCHES

.026 BSC

MIN

NOM MAX

.002 0.00

6.00

MILLIMETERS*

.039

MIN

0.65 BSC

NOM

0.05

1.000.90.035

.001 0.02

Contact Length L .020 .024 .028 0.50 0.60 0.70

Exposed Pad Width

Exposed Pad Length

.140 .146 .152 3.55 3.70 3.85

.031 0.80

5.90 6.10.240.236.232

.232 .236 6.00.240 5.90 6.10

.140 .146 3.70.152 3.55 3.85

PAD OUTLINE

ALTERNATE

SEE DETAIL

DETAIL

TOP VIEW

OPTIONAL

INDEX

AREA

BOTTOM VIEW

METAL

PAD

ALTERNATE

EXPOSED

INDICATORS

INDEX

Revised 05-24-04

Contact Thickness A3 .008 REF 0.20 REF

PIC16F818/819

DS39598E-page 162  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 163
PIC16F818/819
APPENDIX A: REVISION HISTORY
Revision A (May 2002)
Original version of this data sheet.
Revision B (August 2002)
Added INTRC section. PWRT and BOR are indepen-
dent of each other. Revised program memory text and
code routine. Added QFN package. Modified PORTB
diagrams.
Revision C (November 2002)
Added various new feature descriptions. Added inter-
nal RC oscillator specifications. Added low-power
Timer1 specifications and RTC application example.
Revision D (November 2003)
Updated IRCF bit modification information  and changed
the INTOSC stabilization delay from 1 ms to 4 ms in
Section 4.0 “Oscillator Configurations”. Updated
Section 12.17 “In-Circuit Serial Programming” to
clarify LVP programming. In Section 15.0 “Electrical
Characteristics”, the DC Characteristics (Section 15.2
and Section 15.3) have been updated to include the
Typ, Min and Max values and Table 15-1 “External
Clock Timing Requirements” has been updated.
Revision E (September 2004)
This revision includes the DC and AC Characteristics
Graphs and Tables. The Electrical Specifications in
Section 16.0 “DC and AC Characteristics Graphs
and Tables” have been updated and there have been
minor corrections to the data sheet text.
APPENDIX B: DEVICE DIFFERENCES
The differences between the devices in this data sheet are listed in Table B-1.
TABLE B-1: DIFFERENCES BETWEEN THE PIC16F818 AND PIC16F819
Features PIC16F818 PIC16F819
Flash Program Memory (14-bit words) 1K 2K
Data Memory (bytes) 128 256
EEPROM Data Memory (bytes) 128 256

PIC16F818/819

DS39598E-page 164  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E -page 165
PIC16F818/819
INDEX
A
A/D Acquisition Requirements ..........................................84
ADIF Bit ......................................................................83
Analog-to-Digital Converter ........................................81
Associated Registers .................................................87
Calculating Acquisition Time ......................................84
Configuring Analog Port Pins .....................................85
Configuring the Interrupt ............................................83
Configuring the Module ..............................................83
Conversion Clock .......................................................85
Conversion Requirements .......................................142
Conversions ...............................................................86
Converter Characteristics  ........................................141
Delays ........................................................................84
Effects of a Reset .......................................................87
GO/DONE Bit .............................................................83
Internal Sampling Switch (Rss) Impedance ...............84
Operation During Sleep .............................................87
Result Registers .........................................................86
Source Impedance .....................................................84
Time Delays ...............................................................84
Use of the CCP Trigger ..............................................87
Absolute Maximum Ratings  .............................................117
ACK ....................................................................................77
ADCON0 Register ..............................................................81
ADCON1 Register ..............................................................81
ADRESH Register ........................................................ 13, 81
ADRESH, ADRESL Register Pair ......................................83
ADRESL Register ........................................................ 14, 81
Application Notes
AN556 (Implementing a Table Read) ........................23
AN578 (Use of the SSP Module in the 
I2C Multi-Master Environment) ...........................71
AN607 (Power-up Trouble Shooting) .........................92
Assembler
MPASM Ass e mbler ..................................................111
B
BF Bit .................................................................................77
Block Diagrams
A/D .............................................................................83
Analog Input Model ....................................................84
Capture Mode Operation ...........................................66
Compare Mode Operation .........................................67
In-Circuit Serial Programming 
Connections .....................................................101
Interrupt Logic ............................................................96
On-Chip Reset Circuit ................................................91
PIC16F818/819 ............................................................6
PWM ..........................................................................68
RA0/AN0:RA1/AN1 Pins ............................................40
RA2/AN2/VREF- Pin ....................................................40
RA3/AN3/VREF+ Pin ...................................................40
RA4/AN4/T0CKI Pin ...................................................40
RA5/MCLR/VPP Pin ...................................................41
RA6/OSC2/CLKO Pin ................................................41
RA7/OSC1/CLKI Pin ..................................................42
RB0 Pin ......................................................................45
RB1 Pin ......................................................................46
RB2 Pin ......................................................................47
RB3 Pin ......................................................................48
RB4 Pin ......................................................................49
RB5 Pin ..................................................................... 50
RB6 Pin ..................................................................... 51
RB7 Pin ..................................................................... 52
Recommended MCLR Circuit  .................................... 92
SSP in I2C Mode  ........................................................ 76
SSP in SPI Mode ....................................................... 74
System Clock ............................................................. 38
Timer0/WDT Prescaler .............................................. 53
Timer1 ....................................................................... 58
Timer2 ....................................................................... 63
Watchdog Timer (WDT) ............................................. 98
BOR. See Brown-out Reset.
Brown-out Reset (BOR) .............................. 89, 91, 92, 93, 94
C
C Compilers
MPLAB C17 ............................................................. 112
MPLAB C18 ............................................................. 112
MPLAB C30 ............................................................. 112
Capture/Compare/PWM (CCP) ......................................... 65
Capture Mode ............................................................ 66
CCP Prescaler ................................................... 66
Pin Configuration ............................................... 66
Softwar e  In terrup t .............................................. 66
Timer1 Mode Selection ...................................... 66
Capture, Compare and Timer1
Associated Registers ......................................... 67
CCP1IF ...................................................................... 66
CCPR1 ...................................................................... 66
CCPR1H:CCPR1L ..................................................... 66
Compare Mode .......................................................... 67
Pin Configuration ............................................... 67
Software Interrupt Mode .................................... 67
Special Event Trigger ........................................ 67
Special Event Trigger 
Output of CCP1 ......................................... 67
Timer1 Mode Selection ...................................... 67
PWM and Timer2
Associated Registers ......................................... 69
PWM Mo de ................................................................ 68
Duty Cycle ......................................................... 68
Example Frequencies/Resolutions .................... 69
Period ................................................................ 68
Setup for Operation ........................................... 69
Timer Resources ....................................................... 65
CCP1M0 Bit ....................................................................... 65
CCP1M1 Bit ....................................................................... 65
CCP1M2 Bit ....................................................................... 65
CCP1M3 Bit ....................................................................... 65
CCP1X Bit .......................................................................... 65
CCP1Y Bit .......................................................................... 65
CCPR1H Register .............................................................. 65
CCPR1L Register .............................................................. 65
Code Examples
Changing Between Capture Prescalers ..................... 66
Changing Prescaler Assignment from 
Timer0 to WDT .................................................. 55
Changing Prescaler Assignment from 
WDT to Timer0 .................................................. 55
Clearing RAM Using Indirect Addressing .................. 23
Erasing a Flash Program Memory Row ..................... 29
Implementing a Real-Time Clock Using 
a Timer1 Interrupt Service ................................. 62
Initializing PORTA ...................................................... 39
Reading a 16-Bit Free Running Timer ....................... 59

PIC16F818/819
DS39598E-page 166  2004 Microchip Technology Inc.
Reading Data EEPROM .............................................27
Reading Flash Program Memory  ...............................28
Saving Status and W Registers in RAM .....................97
Writing a 16-Bit Free Running Timer ..........................59
Writing to Data EEPROM ...........................................27
Writing to Flash Program Memory .............................31
Code Protection .........................................................89, 100
Computed GOTO ...............................................................23
Configuration Bits ...............................................................89
Crystal Oscillator and Ceramic Resonators  .......................33
D
Data EEPRO M Memor y .....................................................25
Associated Registers .................................................32
EEADR Register ........................................................25
EEADRH Register ......................................................25
EECON1 Register ......................................................25
EECON2 Register ......................................................25
EEDATA Register ......................................................25
EEDATH Register ......................................................25
Operation During Code-Protect ..................................32
Protection Against Spurious Writes ............................32
Reading ......................................................................27
Write Interrupt Enable Flag (EEIF Bit) ........................25
Writing ........................................................................27
Data Memory
Special Function Registers ........................................13
DC and AC Characteristics
Graphs and Tables ...................................................143
DC Characteristics
Internal RC Accuracy ...............................................127
PIC16F818/819, PIC16LF818/819 ...........................128
Power-Down and Supply Current .............................120
Supply Voltage .........................................................119
Demonstration Boards
PICDEM 1 ................................................................114
PICDEM 17 ..............................................................115
PICDEM 18R ............................................................115
PICDEM 2 Plus ........................................................114
PICDEM 3 ................................................................114
PICDEM 4 ................................................................114
PICDEM LIN .............................................................115
PICDEM USB ...........................................................115
PICDEM.net Internet/Ethernet .................................114
Development Support ......................................................111
Device Differences ...........................................................163
Device Overview  ..................................................................5
Direct Addressing ...............................................................24
E
EEADR Register ................................................................25
EEADRH Register ..............................................................25
EECON1 Register ..............................................................25
EECON2 Register ..............................................................25
EEDATA Register ..............................................................25
EEDATH Register ..............................................................25
Electrical Characteristics ..................................................117
Endurance ............................................................................1
Errata ...................................................................................3
Evaluation and Programming Tools .................................115
External Clock Input ...........................................................34
External Interrupt Input (RB0/INT). 
See Interrupt Sources.
F
Flash Program Memory ..................................................... 25
Associated Registers ................................................. 32
EEADR Register ........................................................ 25
EEADRH Register ..................................................... 25
EECON1 Register ...................................................... 25
EECON2 Register ...................................................... 25
EEDATA Register ...................................................... 25
EEDATH Register ...................................................... 25
Erasing ....................................................................... 28
Reading ..................................................................... 28
Writing ........................................................................ 30
FSR Register ....................................................13, 14, 15, 23
G
General Purpose Register File ........................................... 10
I
I/O Por ts ............................................................................. 39
I2CAssociated Registers ................................................. 79
Master Mode Operation ............................................. 79
Mode .......................................................................... 76
Mode Selection .......................................................... 76
Multi-Master Mode Operation .................................... 79
Slave Mode ................................................................ 77
Addressing ......................................................... 77
Reception .......................................................... 77
SCL, SDA Pins .................................................. 77
Transmission ..................................................... 77
ID Locations ................................................................89, 100
In-Circuit Debugger .......................................................... 100
In-Circuit Serial Programming ............................................ 89
In-Circuit Serial Programming (ICSP) .............................. 101
INDF Register .........................................................14, 15, 23
Indirect Addressing .......................................................23, 24
Instruction Format ............................................................ 103
Instruction Set .................................................................. 103
ADDLW .................................................................... 105
ADDWF .................................................................... 105
ANDLW .................................................................... 105
ANDWF .................................................................... 105
BCF .......................................................................... 105
BSF .......................................................................... 105
BTFSC ..................................................................... 106
BTFSS ..................................................................... 106
CALL ........................................................................ 106
CLRF ....................................................................... 106
CLRW ...................................................................... 106
CLRWDT ................................................................. 106
COMF ...................................................................... 107
DECF ....................................................................... 107
DECFSZ .................................................................. 107
Descriptions ............................................................. 105
GOTO ...................................................................... 107
INCF ........................................................................ 107
INCFSZ .................................................................... 107
IORLW ..................................................................... 108
IORWF ..................................................................... 108
MOVF ...................................................................... 108
MOVLW ................................................................... 108
MOVWF ................................................................... 108

 2004 Microchip Technology Inc. DS39598E -page 167
PIC16F818/819
NOP .........................................................................108
Read-Modify-Write Operations ................................103
RETFIE ....................................................................109
RETLW ....................................................................109
RETURN ..................................................................109
RLF ..........................................................................109
RRF ..........................................................................109
SLEEP .....................................................................109
SUBLW ....................................................................110
SUBWF ....................................................................110
Summary Table ........................................................104
SWAPF ....................................................................110
XORLW ....................................................................110
XORWF ....................................................................110
INT Interrupt (RB0/INT).  See Interrupt Sources.
INTCON Register ...............................................................15
GIE Bit ........................................................................18
INTE Bit ......................................................................18
INTF Bit  ......................................................................18
RBIF Bit ......................................................................18
TMR0IE Bit .................................................................18
Internal Oscillator Block .....................................................35
INTRC Modes ............................................................35
Interrupt Sources .......................................................... 89, 96
RB0/INT Pin, External ................................................97
TMR0 Overflow ..........................................................97
Interrupts
RB7:RB4 Port Change ...............................................43
Synchronous Serial Port Interrupt  ..............................20
Interrupts, Context Saving During ......................................97
Interrupts, Enable Bits
Global Interrupt Enable (GIE Bit) ...............................96
Interrupt-on-Change (RB7:RB4) 
Enable (RBIE Bit) ...............................................97
RB0/INT Enable (INTE Bit) ........................................18
TMR0 Overflow Enable (TMR0IE Bit) ........................18
Interrupts, Enable bits
Global Interrupt Enable (GIE Bit) ...............................18
Interrupts, Flag Bits
Interrupt-on-Change (RB7:RB4) Flag 
(RBIF Bit ) .....................................................18, 97
RB0/INT Flag (INTF Bit) .............................................18
TMR0 Overflow Flag (TMR0IF Bit) .............................97
INTRC Modes
Adjustment .................................................................36
L
Loading of PC ....................................................................23
Low-Voltage ICSP Programmin g .....................................102
M
Master Clear (MCLR)
MCLR Reset, Normal Operation .....................91, 93, 94
MCLR Reset, Sleep ........................................91, 93, 94
Operation and ESD Protection ...................................92
Memory Organization ...........................................................9
Data Memory .............................................................10
Program Mem ory  .........................................................9
MPLAB ASM30 Assembler, Linker, Librarian ..................112
MPLAB ICD 2 In-Circuit Debugger ...................................113
MPLAB ICE 2000 High-Perform ance 
Universal In-Circuit Emulator ...................................113
MPLAB ICE 4000 High-Perform ance 
Universal In-Circuit Emulator ...................................113
MPLAB Integrated Development 
Environment Software ............................................. 111
MPLAB PM3 Device Pr ogramm er ................................... 113
MPLINK Object Linker/
MPLIB Object Librarian ............................................ 112
O
Opcode Field Descriptions ............................................... 103
OPTION_R EG Register ..................................................... 15
INTEDG Bit ...........................................................17, 54
PS2:PS0 Bits ............................................................. 17
PSA Bit ...................................................................... 17
RBPU Bit ..............................................................17, 54
T0CS Bit .................................................................... 17
T0SE Bit .................................................................... 17
Oscillator Configuration ..................................................... 33
ECIO .......................................................................... 33
EXTCLK ..................................................................... 93
EXTRC ...................................................................... 93
HS .........................................................................33, 93
INTIO1 ....................................................................... 33
INTIO2 ....................................................................... 33
INTRC ........................................................................ 93
LP .........................................................................33, 93
RC ........................................................................33, 35
RCIO .......................................................................... 33
XT .........................................................................33, 93
Oscillator Control Register ................................................. 37
Modifying IRCF Bits ................................................... 37
Clock Transition Sequence ................................ 37
Oscillator Start-up Timer (OST) ....................................89, 92
Oscillator, WDT .................................................................. 98
P
Packaging Information ..................................................... 157
Marking .................................................................... 157
PCFG0 Bit .......................................................................... 82
PCFG1 Bit .......................................................................... 82
PCFG2 Bit .......................................................................... 82
PCFG3 Bit .......................................................................... 82
PCL Register ....................................................13, 14, 15, 23
PCLATH Register .............................................13, 14, 15, 23
PCON Register .................................................................. 93
POR Bit  ...................................................................... 22
PICkit 1 Flash Starter Kit ................................................. 115
PICSTART Plus Deve lopment 
Programmer ............................................................. 114
Pinout Descriptions
PIC16F818/819 ........................................................... 7
Pointer, FSR ...................................................................... 23
POP ................................................................................... 23
POR. See Power-on Reset.
PORTA ................................................................................ 7
Associated Register Summary .................................. 39
Functions ................................................................... 39
PORTA Register ........................................................ 39
TRISA Register .......................................................... 39
PORTA Register ................................................................ 13

PIC16F818/819
DS39598E-page 168  2004 Microchip Technology Inc.
PORTB .................................................................................8
Associated Register Summary ...................................44
Functions ....................................................................44
PORTB Register ........................................................43
Pull-up Enable (RBPU Bit) ...................................17, 54
RB0/INT Edge Select (INTEDG Bit) .....................17, 54
RB0/INT Pin, External ................................................97
RB7:RB4 Interrupt-on-Change ...................................97
RB7:RB4 Interrupt-on-Change 
Enable (RBIE Bit) ...............................................97
RB7:RB4 Interrupt-on-Change 
Flag (RBIF Bit) .............................................18, 97
TRISB Register ..........................................................43
PORTB Register ..........................................................13, 15
Postscaler, WDT
Assignment (PSA Bit) .................................................17
Rate  Se lec t (PS 2 :PS0 Bits)  ........................................17
Power-Down Mode. See Sleep.
Power-on Reset (POR) ...............................89, 91, 92, 93, 94
POR Status  (PO R  Bit) ................................................22
Power Control (PCON) Register ................................93
Power-Down (PD Bit) .................................................91
Time-o ut (TO Bit) .................................................16, 91
Pow e r-up T imer (PWRT)  ..............................................89, 92
PR2 Register ......................................................................63
Prescaler, Timer0
Assignment (PSA Bit) .................................................17
Rate  Se lec t (PS 2 :PS0 Bits)  ........................................17
PRO MATE II Universal Device Programmer ...................113
Program Counter
Reset Conditions ........................................................93
Program Memory
Interrupt Vector ............................................................9
Map and Stack
PIC16F818 ...........................................................9
PIC16F819 ...........................................................9
Reset Vector ................................................................9
Program Verification .........................................................100
PUSH .................................................................................23
R
R/W Bit ...............................................................................77
RA0/AN0 Pin ........................................................................7
RA1/AN1 Pin ........................................................................7
RA2/AN2/VREF- Pin ..............................................................7
RA3/AN3/VREF+ Pin .............................................................7
RA4/AN4/T0CKI Pin .............................................................7
RA5/MCLR/VPP Pin ..............................................................7
RA6/OSC2/CLKO Pin ..........................................................7
RA7/OSC1/CLKI Pin ............................................................7
RB0/INT Pin .........................................................................8
RB1/SDI/S DA Pi n .................................................................8
RB2/SDO/CCP1 Pin .............................................................8
RB3/CCP1/PGM Pin ............................................................8
RB4/SCK/SCL Pin ................................................................8
RB5/SS Pin ..........................................................................8
RB6/T1OSO/T1CKI/PGC Pin ...............................................8
RB7/T1OS I/ PG D  Pi n  ............................................................8
RBIF Bit ..............................................................................43
RCIO Oscillator Mode ........................................................35
Receive Overflow Indicator Bit, SSPOV .............................73
Register File Map
PIC16F818 .................................................................11
PIC16F819 .................................................................12
Registers
ADCON0 (A/D Control 0) ........................................... 81
ADCON1 (A/D Control 1) ........................................... 82
CCP1CON (Capture/Compare/
PWM Control 1) ................................................. 65
Configuration Word .................................................... 90
EECON1 (Data EEPROM Access 
Control 1) ........................................................... 26
Initialization Conditions (table) ................................... 94
INTCON (Interrupt Control) ........................................ 18
OPTION_REG (Option) ........................................17, 54
OSCCON (Oscillator Control) .................................... 38
OSCTUNE (Oscillator Tuning) ................................... 36
PCON (Power Control) .............................................. 22
PIE1 (Peripheral Interrupt Enable 1) .......................... 19
PIE2 (Peripheral Interrupt Enable 2) .......................... 21
PIR1 (Peripheral Interrupt 
Request (Flag) 1) ............................................... 20
PIR2 (Peripheral Interrupt 
Request (Flag) 2) ............................................... 21
SSPCON (Sy nchronous Serial 
Port Control 1) ................................................... 73
SSPSTAT (Synchronous Serial 
Port Status) ........................................................ 72
Status ......................................................................... 16
T1CON (Timer1 Control) ........................................... 57
T2CON (Timer2 Control) ........................................... 64
Reset ............................................................................89, 91
Brown-out Reset (BOR). See Brown-out Reset (BOR).
MCLR Reset. See MCLR.
Power-on Reset (POR). See Power-on Reset  (POR ).
Reset Conditions for All Registers ............................. 94
Reset Conditions for PCON Register ........................ 93
Reset Conditions for Program Counter ...................... 93
Reset Conditions for Status Register ......................... 93
WDT Reset. See Watchdog Timer (WDT).
Revision History ............................................................... 163
RP0 Bit ............................................................................... 10
RP1 Bit ............................................................................... 10
S
Sales and Support ........................................................... 172
SCL Clock .......................................................................... 77
Sleep .......................................................................89, 91, 99
Software Simulator (MPLAB SIM) .................................... 112
Software Simulator (MPLAB SIM30) ................................ 112
Special Event Trigger ......................................................... 87
Special Features of the CPU ............................................. 89
Special Function Register Summary .................................. 13
Special Function Registers ................................................ 13
SPI Mode
Associated Registers ................................................. 74
Serial Clock ................................................................ 71
Serial  D a ta  In ............................................................. 71
Serial Data Out .......................................................... 71
Slave Select ............................................................... 71
SSP ACK ........................................................................... 77
I2CI2C Operation ..................................................... 76
SSPADD Register .............................................................. 14
SSPIF ................................................................................ 20
SSPOV .............................................................................. 73
SSPOV Bit  ......................................................................... 77

 2004 Microchip Technology Inc. DS39598E -page 169
PIC16F818/819
SSPSTAT Register  ............................................................14
Stack ..................................................................................23
Overflow .....................................................................23
Underflow ...................................................................23
Status Register ............................................................. 13, 15
DC Bit .........................................................................16
IRP Bit ........................................................................16
PD Bit .........................................................................91
TO Bit ................................................................... 16, 91
Z Bit ............................................................................16
Synchronous Serial Port (SSP)  ..........................................71
Overview ....................................................................71
SPI Mode ...................................................................71
Synchronous Serial Port Interrupt ......................................20
T
T1CK P S 0 Bi t ......................................................................57
T1CK P S 1 Bi t ......................................................................57
T1OSCEN Bit .....................................................................57
T1SYNC Bit ........................................................................57
T2CK P S 0 Bi t ......................................................................64
T2CK P S 1 Bi t ......................................................................64
Tad .....................................................................................85
Time-out Sequence ............................................................92
Timer0 ................................................................................53
Associated Registers .................................................55
Clock Source Edge Select (T0SE Bit) ........................17
Clock Source Select  (T0CS  Bit) .................................17
External Clock ............................................................54
Interrupt ......................................................................53
Operation ...................................................................53
Overflow Enable (TMR0IE Bit) ...................................18
Overflow Flag (TMR0IF Bit) .......................................97
Overflow Inte rr u p t ......................................................97
Prescaler ....................................................................54
T0CKI .........................................................................54
Timer1 ................................................................................57
Associated Registers .................................................62
Capacitor Selection ....................................................60
Counter Operation .....................................................58
Operation ...................................................................57
Operation in Asynchronous 
Counter Mode ....................................................59
Operation in Synchronized 
Counter Mode ....................................................58
Operation in Timer Mode ...........................................58
Oscillator ....................................................................60
Oscillator Layout Considerations ...............................60
Prescaler ....................................................................61
Resetting Register Pair (TMR1H, TMR1L) .................61
Resetting Using a CCP Trigger Output ......................61
TMR1H .......................................................................59
TMR1L .......................................................................59
Use as a Real-Time Clock .........................................61
Timer2 ................................................................................63
Associated Registers .................................................64
Output ........................................................................63
Postscaler ..................................................................63
Prescaler ....................................................................63
Prescaler and Postscaler  ...........................................63
Timing Diagrams
A/D Conversion ........................................................142
Brown-out Reset ......................................................133
Capture/Compare/PWM (CCP1) ..............................135
CLKO and I/O ..........................................................132
External Clock ..........................................................131
I2C Bus Data ............................................................ 139
I2C Bus Start/Stop Bits ............................................ 138
I2C Reception (7-Bit Address) ................................... 78
I2C Transmission (7-Bit Address)  .............................. 78
PWM Output  .............................................................. 68
Reset, Watchdog Timer, 
Oscillator Start-up Timer and 
Power-up Timer ............................................... 133
Slow Rise Time (MCLR Tied to VDD 
Through RC Network) ........................................ 96
SPI Master Mode  ....................................................... 75
SPI Master Mode (CKE = 0, SMP = 0) .................... 136
SPI Master Mode (CKE = 1, SMP = 1) .................... 136
SPI Slave Mode (CKE = 0) .................................75, 137
SPI Slave Mode (CKE = 1) .................................75, 137
Time-out Sequence on Power-up 
(MCLR Tied to VDD Through 
Pull-up Resistor) ................................................ 95
Time-out Sequence on Power-up (MCLR 
Tied to VDD Through RC Network): Case 1 ....... 95
Time-out Sequence on Power-up (MCLR 
Tied to VDD Through RC Network): Case 2 ....... 95
Timer0 and Timer1 External Clock .......................... 134
Timer1 Incrementing Edge ........................................ 58
Wake-up from Sleep through Interrupt .................... 100
Timing Parameter Symbology ......................................... 130
Timing Requirements
External Clock .......................................................... 131
TMR0 Register ................................................................... 15
TMR1CS Bit ....................................................................... 57
TMR1H Register ................................................................ 13
TMR1L Register ................................................................. 13
TMR1ON Bit ...................................................................... 57
TMR2 Register ................................................................... 13
TMR2ON Bit ...................................................................... 64
TOUTPS0 Bit ..................................................................... 64
TOUTPS1 Bit ..................................................................... 64
TOUTPS2 Bit ..................................................................... 64
TOUTPS3 Bit ..................................................................... 64
TRISA Register .................................................................. 14
TRISB Register .............................................................14, 15
V
Vdd Pin ................................................................................ 8
Vss Pin ................................................................................. 8
W
Wake-up from Sleep .....................................................89, 99
Interrupts ..............................................................93, 94
MCLR Reset .............................................................. 94
WDT Reset ................................................................ 94
Wake-up Using Interrupts .................................................. 99
Watchdog Timer (WDT) ................................................89, 98
Associated Registers ................................................. 98
Enable (WDTEN Bit) .................................................. 98
INTRC Oscillator ........................................................ 98
Postscaler. See Postscaler, WDT.
Programming Considerations .................................... 98
Time-out Period ......................................................... 98
WDT Reset, Normal Operation .......................91, 93, 94
WDT Reset, Sleep ................................................91, 94
WDT Wake -u p  ........................................................... 93
WCOL ................................................................................ 73
Write Collision Detect Bit,  WCOL ...................................... 73
WWW, On-Line Support ...................................................... 3

PIC16F818/819

DS39598E-page 170  2004 Microchip Technology Inc.

NOTES:

 2004 Microchip Technology Inc. DS39598E-page 171

PIC16F818/819

ON-LINE SUPPORT

Microchip provides on-line support on the Microchip

World Wide Web site.

The web site is used b y Micr ochip as a me ans to mak e

files and information easily available to customers. To

view t he site, the user must have acce ss to the In ternet

and a web browser, such as Netscape® or Microsoft®

Internet Explorer. Files are also available for FTP

download from our FTP site.

Connecting to the Microchip Internet

Web S ite

The Microchip web site is available at the following

URL:

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The file transfer site is available by using an FTP

service to connect to:

ftp://ftp.microchip.com

The web site and file transfer site provide a variety of

services. Users may download files for the latest

Development Tools, Data Sheets, Application Notes,

User’s Guides, Articles and Sample Programs. A vari-

ety of Microchip specific business information is also

available, including listings of Microchip sales offices,

distributors and factory representatives. Other data

available for consideration is:

• Latest Microchip Press Releases

• Technical Support Section with Frequently Asked

Questions

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• Mic rochip Consultant Pr ogram Member Listing

• Links to other useful web sites related to

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• Confere nces for prod ucts, Dev elopment Systems,

technical information and more

• Listing of seminars and events

SYSTEMS INFORMATION AND

UPGRADE HOT LINE

The Systems Information and Upgrade Line provides

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Plus, this line provides information on how customers

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Numbe rs are:

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1-480-792-7302 for the rest of the world.

042003

PIC16F818/819

DS39598E-page 172  2004 Microchip Technology Inc.

READER RESPONSE

It is ou r intent io n to pro vi de you w it h th e b es t docume nta tion po ss ib le to e ns ure succ es sfu l u se of y ou r M ic roc hip prod-

uct. If yo u w i sh to provide yo ur c om me nt s o n o r ga niz ati on, c lari ty, subje ct ma tter an d w a ys in w hi ch ou r d oc um ent a tio n

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Questions:

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DS39598EPIC16F818/819

1. What are the best fe atures of this d ocument?

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?

 2004 Microchip Technology Inc. DS39598E-page 173

PIC16F818/819

PIC16F818/819 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 PIC16F818: Standard VDD range

PIC16F 818T: (Tape and Reel)

PIC16LF818: Extended VDD range

Temperature Range - = 0°C to +70°C

I = -40°C to +85°C (Industrial)

E = -40°C to +125°C (Extended)

Package P = PDIP

SO = SOIC

SS = SSOP

ML = QFN

Pattern QTP, SQTP, ROM Code (factory specified) or

Special Requirements. Blank for OTP and

Windowed devices.

Examples:

a) PIC16LF818-I/P = Industrial temp., PDIP

package, Extend ed VDD limits.

b) PIC16F818-I/SO = Industrial temp., SOIC

package, normal VDD limits.

Note 1: F = CMOS Flash

LF = Low-Power CMOS Flash

2: T = in tape and reel – SOIC, SSOP

packages only.

DS39598E-page 174  2004 Microchip Technology Inc.

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WORLDWIDE SALES AND SERVICE

09/27/04