BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Single Chip Bluetooth System
Pre-Production Information Data Sheet
BC212013A
(UART only version)
BC212015A
(USB and UART version)
October 2001
BlueCore2-External is a single chip radio and baseband
IC for Bluetooth 2.4GHz radios implemented in CMOS
technology.
When used with external ROM containing the CSR
Bluetooth software stack, it provides a fully compliant
Bluetooth system for data and voice communications.
General Description
Figure 1: BlueCore2-External System Architecture
RAM
DSP
µP
I/O
2.4 GHz
Radio
XTAL
SPI
UART/USB
PIO
PCM
8Mbit
FLASH
ROM
RF IN
RF OUT
BlueCore 2-External
TM
Applications
The design is optimised to require few external RF
components to facilitate rapid design of the application
printed circuit board and therefore the fastest possible
time to market and lowest overall cost.
Included in the device are autocalibration and built-in-
self-test (BIST) routines to simplify development, type
approval and production test. All hardware and device
firmware is fully compliant with the Bluetooth
specification.
Device Features
Low power 1.8V operation
Small footprint in 96-Ball VFBGA
Package (6x6mm)
Fully qualified Bluetooth component
0.18µm CMOS technology
Full speed class 2 Bluetooth operation
with full 7 slave piconet support
Support for 8Mbit external Flash
Minimum external components
Operates over full industrial temperature
range (-40≤≤T≤≤105°C)
PC Notebooks
Cellular Handsets
Cordless Headsets
Personal Digital Assistants (PDAs)
Computer Accessories (Compact Flash,
PCMCIA and SD cards)
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Radio
No external trimming is required in production
Operation with common TX/RX terminals
simplifies external matching circuitry and
eliminates external antenna switch
Extensive built-in-self-test minimises end product
final test time
Full RF reference designs are available
Transmitter
Up to +4dBm RF transmit power with level control
from the on-chip 6-bit DAC over a dynamic range
greater than 30dB
Supports Class 2 and Class 3 radios without the
need for an external power amplifier or TX/RX
switch
Receiver
Integrated channel filters
Synthesiser
Fully integrated synthesiser: no external VCO
varactor diode or resonator
Compatible with crystals between 8 and 32MHz
(in multiples of 250kHz), or an external clock
Physical Interfaces
Synchronous serial interface up to 4Mbaud for
software debugging
Full speed USB interface supports OHCI and
UHCI compliant with USB v1.1
Bluetooth Stack Running on
Internal Microcontroller
CSR’s Bluetooth Protocol Stack runs on-chip in a
variety of configurations:
Standard HCI (UART or USB)
Digital demodulator for better sensitivity and co-
channel rejection
Fully embedded to RFCOMM, thus reducing host
CPU load
UART interface with programmable baud rate up
to 1.5Mbaud
Key Features
Supports Class 1 radios with an external power
amplifier provided by a power control terminal
controlled by an internal 8-bit voltage DAC and by
control of an external RF TX/RX switch
Digitised RSSI available in real time over the HCI
Fast AGC for enhanced dynamic range
Synchronous bidirectional serial programmable
audio interface
Optional I2C compatible interface
Stand-alone single chip (no host) including virtual
machine (VM) programming environment, for
instance for headsets and PC peripherals
More information on the CSR Bluetooth Software
Stack and software development tools is available
in separate documentation from CSR.
Baseband and Software
32Kbyte on-chip RAM allows full speed Bluetooth
data transfer, mixed voice and data, plus full 7
slave piconet operation
Trancoders for A-law, µ-law and linear voice from
host and A-law, µ-law and CVSD voice over air
Dedicated logic for forward error correction,
header error control, access code correlation,
demodulation, cyclic redundancy check,
encryption bitstream generation, whitening and
transmit pulse shaping
External 8Mbit Flash ROM for complete system
solution and application flexibility
Auxiliary Features
Crystal oscillator with built-in digital trimming
Power management includes digital shut down
and wake up commands and an integrated low
power oscillator for ultra-low Park/Sniff/Hold mode
power consumption Package Options
96-Ball VFBGA 8x8x1.0mm 0.65mm Pitch
Page 2 of 21
Key Features
96-Ball VFBGA 6x6x1.0mm 0.5mm Pitch
Device can be used with an external master
oscillator and provides a ‘clock request signal’ to
control external clock source
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Microcontroller
Interrupt
controller
Event
timer
RISC
micro-controller Programmable
I/O
PIO[5]/USB_DETACH
PIO[6]/CLK_REQ
PIO[7]/RAM_CSB
PIO[2]/USB_PULL_UP
PIO[3]/USB_WAKE_UP
PIO[4]/USB_ON
VSS_MEM
VSS_PADS
VSS_CORE
Baseband and Logic
UART_TX
UART_RX
UART_RTS
UART_CTS
SPI_CSB
SPI_CLK
SPI_MOSI
SPI_MISO
USB_D+
USB_D-
Synchronous
Serial
Interface
USB
UART
Memory
management
unit
Burst
mode
controller
RAM
Memory
mapped
control/
status
Physical
layer
DSP
hardware
engine
RESET
VDD_ANA
XTAL_OUT
XTAL_IN
VDD_VCO
Clock
generation
VDD_RADIO
RSSI
PIO(0)/RXEN
RF_IN
TX_A
TX_B
PIO[1] / TXEN
PA
LNA
IQ DEMOD
RF
synthesiser
/N/N+1
Tune
LOOP_FILTER
ADC
Demodulator
VSS_ANA
VSS_RADIO
+45
-45
RF Receiver
RF Transmitter
IQ MOD
AUX_DAC
RF Synthesiser
Fref
External
Memory
Driver
CSB
A[18:0]
D[15:0]
WEB
REB
PCM_OUT
PCM_IN
PCM_SYNC
Audio
PCM
Interface
VDD_PADS
VDD_MEM
VDD_CORE
AUX
DAC
VSS_VCO
AIO[0]
AIO[1]
AIO[2]
19
VSS_PIO
16
PCM_CLK
DAC
TEST_EN
PIO[8]
PIO[9]
PIO[10]
PIO[11]
VDD_PIO
Figure 2: BlueCore2-External Device Diagram
Device Diagram
Page 3 of 21
Device Diagram
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
LOOP_FILTER
PIO[0] / RXEN
VDD_PIO VSS_PIO
PIO[5] /
USB DETACH
SPI_CSB SPI_MOSI USB_D- USB_D+ VDD_CORE VSS_CORE VDD_PADS VSS_PADS
PIO[4] / USB_ON
PIO[3] /
USB_WAKE _UP
SPI_MISO SPI_CLK UART_CTS UART_RTS PCM_CLK PCM_OUT PCM_IN PCM_SYNC
PIO[1] / TXEN PIO[6] /
CLK_REQ PIO[9] PIO[10] PIO[11] VSS UART_TX UART_RX CSB VSS_MEM
VDD_ANA
XTAL_IN XTAL_OUT
TX_A
TX_B
RF_IN
VDD_RADIO AUX_DAC
VSS_RADIO
VSS_RADIO
VSS_RADIO
RESET
PIO[7] / RAM_CSB
TEST_EN
VDD_VCO VSS_VCO VDD_RADIO
A[0]
A[1]
A[3]
A[6]
A[9]
A[13]
A[16] A[17]
A[14] A[15]
A[18]D[0]
D[4] D[1] D[2] D[3]
A[12]
VSS_ANA AIO[1] D[13]
AIO[0]VSS_ANA
VSS_VCO AIO[2] D[14]
D[15] D[12]
D[11] D[8]
D[9]
D[10] D[7]
D[6]
D[5]
A[10] A[11]
A[8]A[7]
A[4] A[5]
WEB A[2]
REB VDD_MEM
PIO[8]
PIO[2] /
USB_PULL_UP
Figure 3: BlueCore2-External Device Pinout
Device Pinout Diagram(2)
Orientation from top of device
Page 4 of 21
Device Pinout Diagram
Note:
(1) USB functions are available on BC212015A only.
(2) Device pinout diagram is the same for both 8x8x1mm package (DN) and 6x6x1mm package (EN).
(1) (1) (1)
(1) (1) (1)
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Device Terminal Functions
Terminal Name Pad Type DescriptionBall
RF_IN Analog Single ended receiver inputE1
Control output for external PA Class 1 only
(=PIO[1])
C2
Radio
PIO[0] / RXEN Bidirectional with weak internal
pull-up/down
Control output for external LNA (if fitted)
(=PIO[0])
C1
TX_B Analog Complement of TX_AF1
TX_A Analog Transmitter output/Switched Receiver inputG1
AUX_DAC Voltage DAC outputD2
XTAL_IN For crystal or external clock inputL1
XTAL_OUT Drive for crystalL2
Synthesiser and Oscillator
Synchronous data outputB9
Synchronous data input
USB and UART
Synchronous data clock
B8
Analog
Analog
LOOP_FILTER Connection to external PLL loop filterJ1
PCM_IN CMOS input with
weak internal pull-down B10
Analog
PIO[1] / TXEN Bidirectional with weak internal
pull-up/down
Analog
Note:
(1) See Address and Data Bus tables at the end of this section.
(2) These terminals are available on BC212015A only.
Synchronous data strobePCM_SYNC Bidirectional with
weak internal pull-down B11
UART_TX UART data output
C8
CMOS output
UART_RX UART data input
C9
CMOS input with weak internal
pull-down
UART_RTS UART ready to send
B7
CMOS output, tristatable with
internal weak pull-up
UART_CTS UART clear to send
B6
CMOS input with weak internal
pull-down
USB_D+ (2) USB data plus
A7
Bidirectional
USB_D-(2) USB data minus
A6
Bidirectional
Page 5 of 21
Device Terminal Functions
REB Read enable for external memory (active low)D10
WEB Write enable for external memory (active low)E10
External Memory Port
CMOS output, tristatable with
internal weak pull-up
CMOS output, tristatable with
internal weak pull-up
CSB Chip select for external memory (active low)C10
CMOS output, tristatable with
weak internal pull-up
PCM Interface
A[18:0] Address lines
(1)
CMOS output
D[15:0] Data bus
(1)
Bidirectional with
weak internal pull-down
PCM_CLK Bidirectional with
weak internal pull-down
PCM_OUT CMOS output, tristatable with
weak internal pull-down
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Terminal Name Pad Type DescriptionBall
PIO[2] /USB_PULL_UP (1) Bidirectional with programmable
weak internal pull-up/down
PIO or USB pull-up (via 1.5kΩ resistor to
USB_D+)
B3
PIO or Output goes high to wake up PC when
in USB mode
B2
PIO Port
PIO[4] /USB_ON (1) Bidirectional with programmable
weak internal pull-up/down
PIO or USB on (input senses when VBUS is
high, wakes BlueCore2-External)
B1
PIO[6] / CLK_REQ Bidirectional with programmable
weak internal pull-up/down PIO line or clock request for external clock lineC3
PIO[5] / USB_DETACH (1) Bidirectional with programmable
weak internal pull-up/down
PIO line or chip detaches from USB when this
input is high
A3
PIO[11] Programmable Input/Output lineC6
PIO[3] /USB_WAKE_UP (1) Bidirectional with programmable
weak internal pull-up/down
Bidirectional with programmable
weak internal pull-up/down
AIO[0] Programmable Input/Output lineK3Bidirectional
AIO[1] Programmable Input/Output lineL4Bidirectional
AIO[2] Programmable Input/Output lineJ3Bidirectional
Device Terminal Functions
PIO[7] / RAM_CSB Programmable Input/Output lineE3
Bidirectional with programmable
weak internal pull-up/down
PIO[8] Programmable Input/Output lineD3
Bidirectional with programmable
weak internal pull-up/down
PIO[9] Programmable Input/Output lineC4
Bidirectional with programmable
weak internal pull-up/down
PIO[10] Programmable Input/Output lineC5
Bidirectional with programmable
weak internal pull-up/down
Page 6 of 21
RESET Reset if highF3
SPI_CLK Synchronous Serial Interface ClockB5
Chip select for Synchronous Serial InterfaceA4
Test and Debug
SPI_MOSI Synchronous Serial Interface data inputA5
CMOS input with weak internal
pull-down
CMOS input with weak internal
pull-down
CMOS input with weak internal
pull-down
SPI_CSB CMOS input with weak internal
pull-up
SPI_MISO Synchronous Serial Interface data outputB4
CMOS output, tristatable with
weak internal pull-down
TEST_EN For test purposes only (leave unconnected)G3
CMOS input with strong internal
pull-down
Note:
(1) USB functions are available on BC212015A only.
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Terminal Ball
A[1]
A[0]
Address Lines
Terminal Ball
D[1] L9
D[0] K8
Data Bus
A[4]
A[5]
A[6]
A[8]
A[9]
D[2] L10
D[3] L11
D[4] L8
D[5] J7
D[6] K7
D9
E9
F10
F11
G9
G11
H9
A[10] H10
A[11] H11
A[12] J8
A[13] J9
A[14] J10
A[15] J11
A[16] K9
A[17] K10
D[7] L7
D[8] J6
D[9] K6
D[10] L6
D[11] J5
D[12] K5
D[13] L5
D[14] J4
D[15] K4
A[2] E11
A[3] F9
A[7] G10
A[18] K11
Page 7 of 21
Device Terminal Functions
VDD_CORE Positive supply for internal digital circuitryA8
VDD_RADIO Positive supply connection for RF circuitryD1, H3
Power Supplies and Control
VDD_PIO Positive supply for PIO & AUX DACA1
Positive supply for all other Input/Output
VDD_ANA Positive supply for analogue circuitry
K1
VSS_CORE Ground connection for internal digital circuitryA9
VDD
VDD
VDD_VCO Positive supply for VCO and synthesiser
circuitry
H1
VDD_PADS VDD
VDD
VDD
VSS
A10
VDD
VSS_RADIO Ground connections for RF circuitry
E2,
F2,G2
VSS
VSS_VCO Ground connections for VCO and synthesiserJ2, H2VSS
VSS_PADS Ground connection for Input/Output except
memory port
A11
VSS
VSS_PIO Ground connection for PIO & AUX DACA2VSS
VSS_MEM Ground connection for external memory portC11VSS
VDD_MEM Positive supply for external memory port & AIOD11VDD
VSS_ANA Ground connections for analogue circuitryL3, K2VSS
VSS Ground connection for internal package shieldC7VSS
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Absolute Maximum Ratings
Storage Temperature -40°C +105°C
Supply Voltage: VDD_PADS, VDD_PIO, VDD_MEM -0.4V 3.6V
Rating
Other Terminal Voltages (except 5V tolerant) VSS-0.4V VDD+0.4V
Operating Temperature range -40°C 105°C
Supply Voltage: VDD_RADIO, VDD_VCO,
VDD_ANA, VDD_CORE 1.70V 1.90V
Operating Condition
Supply Voltage: VDD_PADS, VDD_PIO, VDD_MEM 1.70V 3.60V
Recommended Operating Conditions
Min Max
Min Max
Electrical Characteristics
Digital Terminals
Electrical Characteristics
Supply Voltage: VDD_RADIO, VDD_VCO,
VDD_ANA, VDD_CORE -0.4V 1.9V
Page 8 of 21
Input Voltage
VIL input logic level low (VDD=3.0V)
(VDD=1.8V)
VIH input logic level high
Output Voltage
VOL output logic level low, (IO = 4.0mA), VDD=3.0V
VOL output logic level low, (IO= 4.0mA), VDD=1.8V
VOH output logic level high, (IO = 4.0mA), VDD=3.0V
VOH output logic level high, (IO= 4.0mA), VDD=1.8V
Tri-state Leakage Current (See input current except for)
SPI_MISO, PCM_OUT, UART_RTS
CSB, WEB, REB: (VDD=3.0V)
(VDD=1.8V)
CIInput Capacitance
Input Current
TEST_EN input high IIH
SPI_CSB input low IIL
PIO with pull up selected input low IIL
All other inputs, in any state II (0V≤VIN<VDD)
Note:
Current drawn into a pin is defined as positive, current supplied out of a pin is defined as negative.
Input/Output Terminal Characteristics
Min UnitMaxTyp
-
-
-
+0.8
+0.4
VDD+0.4
V
V
V
-0.4
-0.4
0.7VDD
-
-
-
-
+200
-1
-1
+5
-
-
-
-
-
-
-
0.2
0.4
-
-
+5
+2
10
-
-
VDD-0.2
VDD-0.4
-1
-1
2.5
µA
µA
µA
µA
V
V
V
V
µA
µA
pF
+10
-5
-5
-1
VDD_CORE, VDD_RADIO, VDD_VCO and VDD_ANA are at 1.8V unless shown otherwise
VDD_PADS, VDD_PIO and VDD_MEM are at 3.0V unless shown otherwise
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Power-on Reset
Input/Output Terminal Characteristics (continued)
1.4
1.6
0.2
-
-
-
V
V
V
Min UnitMaxTyp
-
-
-
V
V
-
0.7VDD_PADS
VDD falling threshold
VDD rising threshold
Hysteresis
Input threshold
VIL input logic level low
VIH input logic level high
USB Terminals Min Typ UnitMax
-
-
0.3VDD_PADS
-
µA
-1
Input leakage current, VSS_PADS<VIN<VDD_PADS - 1
pF2.5CI Input Capacitance - 10
V
V
0
2.8
Output levels to correctly terminated USB cable
VOL output logic level low
VOH output logic level high
-
-
0.2
VDD_PADS
Electrical Characteristics
Page 9 of 21
bits
mV
Resolution
Output Step Size
Auxiliary DAC Min Typ UnitMax
13
8
V
mA
V
V
µA
VSS_PIO
-10
0
VDD_PIO-0.3
-1
Output voltage
Voltage range (IO = 0)
Current range
Minimum output voltage (IO = 200µA)
Maximum output voltage (IO = -10mA)
Tristate leakage current
-
-
-
-
-
VDD_PIO
+0.2
0.2
VDD_PIO
+1
LSB
µs
Accuracy
Gain Error
Offset
Linearity
Settling Time (50pF load)
±5%
±3
Monotonic
5
Note:
(1) Integer multiple of 250kHz.
(2) The difference between the local capacitance at minimum and maximum settings of the internal digital trim.The same
setting of the digital trim is applied to both XTAL_IN and XTAL_OUT.
Current drawn into a pin is defined as positive, current supplied out of a pin is defined as negative.
MHz8.0Crystal frequency (1)
Crystal Oscillator Min Typ UnitMax
- 32.0
pF5Digital trim range (1) (2) 6.2 8
pF-Trim step size (2) 0.1 -
mS2.0Negative tranconductance - -
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Radio Characteristics
VDD = 1.8V Temperature = 20°C Frequency=2.441GHz
Notes:
(1) Measured according to the Bluetooth specification.
(2) Up to five spurious responses within Bluetooth limits are allowed.
(3) At carrier -3MHz.
(4) Measured at f1-f2=5MHz.
(5) For 0.1% BER with wanted input at -67dBm, and with the RF filter removed from the circuit.
Results shown are referenced to input of the RF balun.
Electrical Characteristics
Page 10 of 21
Unit
Sensitivity at 0.1% BER (1) dBm
dB
Bluetooth
Specification
Receiver
C/I Co-channel (1)
≤-70
≤11
9
dBAdjacent channel selectivity C/I 1MHz (1) ≤0
-2.0
dB2nd adjacent channel selectivity C/I 2MHz (1) ≤-30
-34
dB
3rd adjacent channel selectivity C/I ≥3MHz (1) (2) ≤-40
-43
-85
Max
-
-
-
-
-
-
-
-
-
-
dBmMaximum level of GSM signal at 1.8GHz (5) --7 --
Bluetooth
Specification
Transmitter Typ Max
Min
Maximum RF transmit power (1) -6 to +47.0 --
≥16
30
RF power range control resolution -2.0
20dB bandwidth for modulated carrier ≤1000
900
-
-
-
-
-
3rd adjacent channel transmit power (1) ≤-40
Unit
dBm
dB
dB
kHz
dBm
TypMin
-
dBImage rejection C/I (1) (3) ≤-9
-12
dBmMaximum level of intermodulation interferers (1) (4) ≤-39
-30
-
-
-
-
RF power control range (1) -
2nd adjacent channel transmit power (1) ≤-20
-dBm-52 -
--57
Maximum received signal at 0.1% BER(1) dBm-5.0 ≥-20
--
dBmMaximum level of W-CDMA signal at 1.8GHz (5) --9.5 --
dBmMaximum level of W-CDMA signal at 2.2GHz (5) --11 --
Unit
SCO connection HV3 (1s interval sniff mode) (Slave) mA
mA
SCO connection HV1 (Slave) mA
PeakMode Avg
Current Consumption(1)
VDD = 1.8V Temperature = 20°C
53
ACL data transfer 115.2kbps UART (Master)
-
-
-15
mAACL data transfer 720kbps USB (Master) -61
28
SCO connection HV3 (1s interval sniff mode) (Master) mA-28
SCO connection HV1 (Master) mA53 -
mAACL data transfer 720kbps USB (Slave) -61
mAACL connection, Sniff Mode 40ms interval, 38.4kbps UART -4
mAACL connection, Sniff Mode 1.28s interval, 38.4kbps UART -0.5
mAParked Slave, 1.28s beacon interval, 38.4kbps UART -0.6
µA
Deep Sleep Mode -15
mAPeak RF current during RF burst -80
Note:
(1) Current consumption is for BC212015A and includes current supplied to external 3V Flash ROM.
1.8V Flash ROM will further reduce this figure.
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Description of Functional Blocks
Radio Transceiver and Synthesiser
The receiver features a near-zero IF architecture that
allows the channel filters to be integrated on to the die.
Sufficient out-of-band blocking specification at the LNA
input allows the radio to be used in close proximity to
GSM and W-CDMA cellular phone transmitters without
being de-sensitised. The use of a digital FSK
discriminator means that no discriminator tank is
needed and its excellent performance in the presence
of noise allows BlueCore2-External to exceed the
Bluetooth requirements for co-channel and adjacent
channel rejection. Fast AGC is implemented by
measuring the RSSI on a slot-by-slot basis and
adjusting the front-end LNA gain to keep the first mixer
input signal within a limited range. This improves the
dynamic range of the receiver in interference-limited
environments.
The transmitter features a direct IQ modulator to
minimise the frequency drift during a transmit timeslot
and results in a well controlled modulation index. A
digital baseband transmit filter provides the required
spectral shaping.
The maximum transmit power of +7dBm allows
BlueCore2-External to be used in Class 2 and Class 3
radios and its support for transmit power control allows
a simple implementation for Class 1 with an external
RF power amplifier.
The radio synthesiser is fully integrated with no
requirement for an external VCO screening can,
varactor tuning diodes or LC resonators.
The radio has several built-in automatic calibration
routines to maintain the radio performance within
specification across temperature and ageing. No LNA ,
PA or TX/RX switch is required for Class 2 operation
aross the device’s full operating temperature range.
Auxiliary Features
The device contains two clock sources: one reference
oscillator for the RF carrier frequency and one low
frequency clock oscillator that is used as an interval
timer during sleep modes, i.e., Sniff, Hold or Park.
The reference oscillator requires an external crystal.
Alternatively, the crystal terminals can be driven from
an external reference clock.The reference frequency
can be in the range of 8-32MHz in multiples of
250kHz.
The low frequency clock oscillator requires no external
components. It is calibrated automatically and
maintains an accuracy of better than 250ppm. This
oscillator consumes less than 2µA and is permanently
enabled.
Physical Layer DSP Hardware Engine
Dedicated logic is used for forward error correction,
header error control, cyclic redundancy check,
encryption, data whitening, access code correlation
and audio transcoding to translate between A-law, µ-
law and linear voice data from the host and A-law,
µ-law and Continuously Variable Slope Delta (CVSD)
voice data over the air, voice interpolation for lost
packets and rate mismatches are performed by the
software.
Burst Mode Controller
During radio transmission the Burst Mode Controller
(BMC) constructs a packet from header information
previously loaded into memory-mapped registers by
the software and payload data/voice taken from the
appropriate ring buffer in RAM. During radio
receptions, the burst mode controller stores the packet
header in memory-mapped registers and the payload
data in the appropriate ring buffer in RAM. This
architecture minimises the intervention required by the
processor during transmission and reception.
Microcontroller, Interrupt Controller and
Event Timer
The microcontroller, interrupt controller and event timer
run the Bluetooth software stack and control the radio
and host interfaces. A 16-bit RISC microcontroller is
used for low power consumption and efficient use of
memory.
Memory Management Unit
The memory management unit provides a number of
dynamically allocated ring buffers that hold the data
which is in transit between the host and the air or vice
versa. The dynamic allocation of memory ensures
efficient use of the available RAM and is performed by
a hardware memory management unit to minimise the
overheads on the processor during data/voice
transfers.
RAM
32Kbytes of on-chip RAM is provided and is shared
between the ring buffers used to hold voice/data for
each active connection and the general purpose
memory required by the Bluetooth stack.
ROM
Up to 8Mbits of external Flash or masked programmed
ROM (16 bit data words) can be attached giving
maximum flexibility for running complete applications
on chip. The ROM can be programmed over the
synchronous serial/UART or USB interfaces after the
device is mounted in the target application.
Description of Functional Blocks
Page 11 of 21
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
CSR Bluetooth Software Stack
BlueCore2-External is supplied with Bluetooth stack
firmware that runs on its microcontroller and is
resident in the external Flash memory. The stack
occupies 4Mbits of storage.
The BlueCore Stack Software is compliant with the
Bluetooth v1.1 specification. It implements all the
features described in the specification, including
optional features.
Piconets: up to seven slaves.
Power Saving: Hold, Sniff and Park
Data integrity: Channel Quality Driven Data Rate
(CQDDR) and RSSI
Audio: full support for SCO
Role Switch: can reverse master/slave relationship
Device Firmware Upgrade
BlueCore2-External is supplied with boot loader
software which implements a standard Device
Firmware Upgrade (DFU) capability. This allows new
firmware to be uploaded to the external Flash
memory through BlueCore2-External's UART/USB
ports.
Additional Software for Host
Implementation
A companion device, BlueCore2-PC can be ordered
which includes software for a full Windows 98/ME or
Windows 2000 Bluetooth host-side stack and
application together with the IC hardware described in
this datasheet. Contact CSR for more details.
Additional Software for Other Embedded
Applications
When the upper layers of the Bluetooth protocol stack
are run as firmware on BlueCore2-External a UART
software driver is supplied that presents the HCI,
L2CAP, RFCOMM and Service discovery APIs to
higher Bluetooth stack layers running on the host.
The code is provided as ‘C’ source or object code.
Other software drivers can be developed on request.
Contact CSR Sales for more information.
Casira Development System
This is available to allow the evaluation of BlueCore2-
External hardware and software and as the base of a
toolkit for developing host software. Contact CSR
Sales for more information.
Profiles Supported Via HCI
The supplied software stack is a full implementation
of Bluetooth up to and including HCI, so all profiles
and associated applications are supported.
Application Specific Software Development
Environment
Firmware supplied with BlueCore2-External contains
a protected user software execution environment as a
Virtual Machine (VM). The user may write custom
application code to run on the BlueCore VM using the
BlueLab software development kit, available
separately from CSR. This code will then execute
alongside the main BlueCore firmware. The user is
able to make calls to the BlueCore firmware for
various operations.
The execution environment is structured so the user
application does not adversely affect the main
software routines, thus ensuring that the Bluetooth
stack software component does not need re-
qualification when the application is changed.
Using the VM and BlueLab, the user is able to
develop applications such as a cordless headset or
other profiles without the requirement of a host
controller. BlueLab is supplied with example code,
including a full implementation of the headset profile.
CSR Bluetooth Software Stack
Page 12 of 21
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Transmitter/Receiver Inputs/Output
Terminals TX_A and TX_B form a balanced current
output. They require a DC connection to VDD and
should be connected through a balun to the antenna.
The output impedance is capacitive and remains
constant irrespective of whether the transmitter is
enabled or disabled. For Class 2 operation these
terminals also act as differential receive input
terminals with an internal TX/RX switch.
For Class 1 operation the RF_IN ball is provided,
which is single-ended and presents a capacitive
input. A swing of up to 0.5V rms can be tolerated at
this terminal. An external antenna switch can be
connected to RF_IN.
Asynchronous Serial Data Port (UART)
and USB Port
UART_TX, UART_RX, UART_RTS, and UART_CTS
form a conventional asynchronous data serial port.
The interface is designed to operate correctly when
connected to other UART devices such as the
NS16550A. The signalling levels are 0V and
VDD_PADS. The interface is programmable over a
variety of bit rates; no, even or odd parity; one or two
stop bits and hardware flow control on or off. The
default condition on power-up is pre-assigned in the
external Flash memory.
The maximum UART data rate is 1.5Mbit/s. Two-way
hardware flow control is implemented by UART_RTS
and UART_CTS. UART_RTS is an output and is
active low. UART_CTS is an input and is active low.
These signals operate according to normal industry
convention.
The port carries a number of logical channels: HCI
data (both SCO and ACL), HCI commands and
events, L2CAP API, RFCOMM API, Service
Discovery API and device management. For the
UART, these are combined into a robust tunnelling
protocol, BlueCore Serial Protocol (BCSP), where
each channel has its own software flow control and
cannot block other data channels. In addition, the
Bluetooth specification part H4 format is supported.
Alternatively a firmware version is available to support
full speed (12Mbit/s) USB. USB_D+ and USB_D- are
available on dedicated terminals. Both Open Host
Controller Interface (OHCI) and Upper Host Controller
Interfaces (UHCI) are supported.
The firmware in Flash can be downloaded through
this port by DFU if the CSR-supplied boot loader is
first programmed.
Firmware shipped with BlueCore2-External includes
security features to prevent misuse of this upgrade
facility.
PCM Codec Interface
PCM_OUT, PCM_IN, PCM_CLK, PCM_SYNC carry
up to three bidirectional channels of voice data, each
at 8 ks/s. The format of the PCM samples can be
8-bit A-law, 8-bit µ-law, 13-bit linear or 16-bit linear.
The PCM_CLK and PCM_SYNC terminals can be
configured as inputs or outputs depending on whether
BlueCore2-External is the master or slave of the PCM
interface.
BlueCore2-External interfaces directly to PCM audio
devices such as the:
Qualcomm MSM 3000 series and MSM 5000 series
CDMA devices,
OKI MSM7705 four channel µ/A-law codec,
Motorola MC145481 8-bit µ/A-law codec,
Motorola MC145483 13-bit linear codec and the
Mitel MT93LI6 Echo cancelling codec.
BlueCore2-External is also compatible with the
Motorola SSITM interface.
Synchronous Serial Port
BlueCore2-External is a slave device using terminals
SPI_MOSI, SPI_MISO, SPI_CLK and SPI_CSB. This
interface is used for program emulation/debug and IC
test. It is also the means by which the external Flash
ROM may be programmed ‘in situ’ before any 'boot'
program is loaded. The designer should be aware
that no security protection is built into the hardware or
firmware associated with this port.
Parallel PIO Port
Fifteen lines of programmable bidirectional I/O are
provided. PIO[11:0] are powered from VDD_PIO and
AIO[2:0] are powered from VDD_MEM. PIO[0] and
PIO[1] are normally dedicated to TXEN and RXEN,
but they are available for general use. Any of the PIO
lines can be configured as interrupt request lines or
as wake-up lines from sleep modes. PIO[6] can be
configured as a request line for an external clock
source. This is useful when the clock to BlueCore2-
External is provided from a system ASIC.
I2C Interface
PIO[3] and PIO[2] can be used to form a master I2C
interface. The interface is formed using software to
drive these lines and is thus suited only to relatively
slow functions such as driving a dot matrix LCD
display, a keyboard scanner or an EEPROM.
External Interfaces
External Interfaces
Page 13 of 21
Page 14 of 21
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
-170
-160
-150
-140
-130
-120
-110 -100 -90 -80 -70
-60
-50
-40
-30
-20
-10
5.00
-5.00
2.00
-2.00
1.00
-1.00
0.50
-0.50
0.20
-0.20
0.0
5.002.001.000.500.200.000.000.000.000.000.000.000.000.00
1.0 1.00.0
1
2
TX_A (Transmit Mode)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
-170
-160
-150
-140
-130
-120
-110 -100 -90 -80 -70
-60
-50
-40
-30
-20
-10
5.00
-5.00
2.00
-2.00
1.00
-1.00
0.50
-0.50
0.20
-0.20
0.0
5.002.001.000.500.200.000.000.000.000.000.000.000.000.00
1.0 1.00.0
1
2
TX_A (Receive Mode)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
-170
-160
-150
-140
-130
-120
-110 -100 -90 -80 -70
-60
-50
-40
-30
-20
-10
5.00
-5.00
2.00
-2.00
1.00
-1.00
0.50
-0.50
0.20
-0.20
0.0
5.002.001.000.500.200.000.000.000.000.000.000.000.000.00
1.0 1.00.0
1
2
TX_B (Transmit Mode)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
-170
-160
-150
-140
-130
-120
-110 -100 -90 -80 -70
-60
-50
-40
-30
-20
-10
5.00
-5.00
2.00
-2.00
1.00
-1.00
0.50
-0.50
0.20
-0.20
0.0
5.002.001.000.500.200.000.000.000.000.000.000.000.000.00
1.0 1.00.0
1
2
TX_B (Receive Mode)
1: ZTTX_A(2402GHz) = (12.7 - j21.95)
2: ZTTX_A(2480GHz) = (12.7 - j20.75)
1: ZTTX_B(2402GHz) = (13.9 - j22.8)
2: ZTTX_B(2480GHz) = (13.3 - j20.85)
1: ZRTX_A(2402GHz) = (7.65 - j28.8)
2: ZRTX_A(2480GHz) = (7.65 - j27.2)
1: ZRTX_B(2402GHz) = (7.55 - j31.1)
2: ZRTX_B(2480GHz) = (7.45 - j28.8)
Application Information
Application Information
Pre-Production Information
Figure 4: TX_A and TX_B Transmit and Receive modes impedance data
Transmit and receive port impedances for 8x8x1mm package
Note:
TX_A is in antiphase with TX_B.
ZTTX_A, ZTTX_B are the output impedances of ports TX_A and TX_B with BlueCore2-External in transmit mode.
ZRTX_A, ZRTX_B are the output impedances of ports TX_A and TX_B with BlueCore2-External in receive mode.
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Typical Radio Performance
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
20
-35 -25 -15 -5 5 15 25 35 45 55 65 75 85 95 105
Temperature (°C)
dBm
Minimum allowed transmit power (Class 2)
Minimum allowed sensitivity
BlueCore2-External minimum detectable signal strength
BlueCore2-External transmit power
200
150
0
100
50
-50
-100
-200
-150
0 0.2 0.4 0.6 0.8-0.2-0.4-0.6-0.8
Pre-Production Information Page 15 of 21
Notes:
Results obtained using CSRs evaluation circuit, see figure 9.
Transmit power: 7dBm.
Data: complete DH5 packet including pre-amble.
Temperature: 20°C.
Note:
Results obtained using CSRs evaluation circuit, see figure 9.
Application Information
Figure 5: Transmit power and receive sensitivity versus temperature
Figure 6: Transmitter Eye Diagram
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
-80
-70
-60
-50
-40
-30
-20
-10
0
10
2.431 2.433 2.435 2.437 2.439 2.441 2.443 2.445 2.447 2.449 2.451
Frequency (GHz)
Power (dBm)
(1) (1)
(2) (2)
Notes:
(1) Maximum allowed adjacent channel power (f=f0 + 2MHz).
(2) Maximum allowed adjacent channel power (f=f0 + 3MHz).
Measurement resolution bandwidth = 100kHz.
Results obtained using CSR’s evaluation circuit, see figure 9.
Temperature: 20°C.
Pre-Production Information
Page 16 of 21
Application Information
-60
-50
-40
-30
-20
-10
0
10
2.4400 2.4405 2.4410 2.4415 2.4420
Frequency (GHz)
Power (dBm)
(1) (1)
Notes:
(1) Maximum allowed 20dB bandwidth.
Measurement resolution bandwidth = 10kHz.
Results obtained using CSR’s evaluation circuit, see figure 9.
Temperature: 20°C.
Figure 7: Wideband transmit spectrum
Figure 8: Narrowband transmit spectrum
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
12345678
A
B
C
D
8
7
6
5
4
3
2
1
D
C
B
A
VDD_PIO A1
VSS_PIO
A2
PIO_5 A3
SPI_CSB A4
SPI_MOSI A5
USB_DN A6
USB_DP A7
VDD_CORE A8
VSS_CORE
A9
VDD_PADS A10
VSS_PADS
A11
PIO_4 B1
PIO_3 B2
PIO_2 B3
SPI_MISO B4
SPI_CLK B5
UART_CTS B6
UART_RTS B7
PCM_CLK B8
PCM_OUT B9
PCM_IN B10
PCM_SYNC B11
PIO_0 C1
PIO_1 C2
PIO_6 C3
PIO_9 C4
PIO_10 C5
PIO_11 C6
VSS
C7
UART_TX C8
UART_RX C9
CSB
C10
VSS_MEM
C11
VDD_RADIO D1
AUX_DAC
D2
PIO_8 D3
A_0
D9
REB
D10
VDD_MEM D11
RX_IN
E1
VSS_RADIO
E2
PIO_7 E3
A_1
E9
WEB
E10
A_2
E11
TX_B
F1
VSS_RADIO
F2
RST F3
A_3
F9 A_4
F10 A_5
F11
TX_A
G1
VSS_RADIO
G2
TEST_EN G3
A_6
G9 A_7
G10 A_8
G11
VDD_VCO H1
VSS_VCO1
H2 VDD_RADIO H3
A_9
H9 A_10
H10 A_11
H11
TUNE
J1
VSS_VCO2
J2
AIO_2 J3
D_14
J4
D11
J5
D_8
J6
D_5
J7
A_12
J8 A_13
J9 A_14
J10 A_15
J11
VDD_ANA K1
VSS_ANA1 K2
AIO_0 K3
D_15
K4
D_12
K5
D_9
K6
D_6
K7
D_0
K8
A_16
K9 A_17
K10 A_18
K11
XTAL_IN L1
XTAL_OUT L2
VSS_ANA2
L3
AIO_1 L4
D_13
L5
D_10
L6
D_7
L7
D_4
L8
D_1
L9 D_2
L10 D_3
L11
U1
BC02
VSUP
C12
10n
C10
3p3
C11
10p
R3
1k
C4
47p
1V8
C6
47p
1V8 VSUP
C7
10n
1V8
C5
10n
1V8
C15
4u7
L2
3n3
L3
3n3
C1
2p2
C2
2p2
Z=50
RF IN/OUT
L1
6n8
C18
47p
1V8
C14
220p
R2
180k
C13
NF
1
2
3
4
5
6
T1
HHM-1517
C8
10n
VSUP VSUP
GND 1
GND 2
PIN 5
GND 3
GND 4
CON2
C9
10n
A3 A1
A7 B1
NC
D3
WEB D1
A9 E1
A13 F1
A4 A2
A17 B2
NC
C1
A8 E2
A12 F2
A2 A3
A6 B3
A10 E3
A14 F3
NC
C2
A1 A4
A5 B4
NC
D2 NC
C4
A11 E4
A15 F4
A0 A5
DQ0 B5
DQ2 C5
DQ5 D5
DQ7 E5
A16 F5
CEB A6
DQ8 B6
DQ10 C6
DQ12 D6
DQ14 E6
OEB A7
DQ9 B7
DQ11 C7
VDD D7
DQ13 E7
DQ15 F7
VSS
F8
DQ1 B8
DQ3 C8
DQ4 D8
DQ6 E8
VSS
A8 A18 C3
NC/A19
D4
VDDQ F6
U2
SST39VF800-90-4CBK
VIN
1
GND
2
CE
3
BYP
4
VOUT 5
U3
XC6204B182MR
VSUP 1V8
C17
4u7
XT1
16MHz TSX-8
C16
10n
RX_IN
R1
0R
C3
100n
GND
1
3V15
2
GND
3
3V15_PA
4
SPI_MISO
5
RESET
6
UART_TX
7
SPI_MOSI
8
UART_RTS
9
SPI_CSB
10
PCM_OUT
11
SPI_CLK
12
PCM_CLK
13
UART_RX
14
PCM_SYNC
15
UART_CTS
16
USB_DP
17
PCM_IN
18
USB_DN
19
PIO_2
20
PIO_0
21
PIO_3
22
PIO_1
23
PIO_5
24
PIO_4
25
PIO_6
26 PIO_7
27
TEST_A
28
GND
29
TEST_B
30
CON1
TO CASIRA
VSUP
IN 1
GND
2GND 3
OUT
4
F1
MDR741F
AUX_DAC
Figure 9: Evaluation circuit for BlueCore2-External module from which the data sheet test
measurements were obtained
Evaluation Circuit
Pre-Production Information
BlueCore2-External
(USB Version)
BC212015A
Page 17 of 21
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Top View Bottom View
Package Dimensions
Figure 10: BlueCore2-External package dimensions
Package Dimensions
98765432110
A
B
C
D
E
F
G
H
J
K
11
SEATING
PLANE
SEE DETAIL K
DETAIL K
Z
A
(A2)
(A3)
2
A1
3
0.08
Z
0.1 Z
D1
PIN 1
CORNER
E1
10X e
Øb1
3456789101121
D
PIN A1
E
DIM MIN MAX NOTES
A
A1
A2
A3
0.25
D
E
e
D1
E1
1
2
3
DIMENSION b IS MEASURED AT THE MAXIMUM
SOLDER BALL DIAMETER PARALLEL TO DATUM
PLANE Z.
DATUM Z IS DEFINED BY THE SPHERICAL
CROWNS OF THE SOLDER BALLS.
PARALLELISM MEASUREMENT SHALL EXCLUDE
ANY EFFECT OF MARK ON TOP SURFACE OF
PACKAGE.
0.8 1
0.2 0.3
0.22 REF
0.45 REF
0.35
6 BSC
6 BSC
0.5 BSC
5 BSC
5 BSC
VFBGA 96 BALLS
6X6X1mm
(JEDEC MO-225)
b
DIM MIN MAX NOTES
A
A1
A2
A3
0.25
D
E
e
D1
E1
UNIT
MM
1
2
3
DIMENSION b IS MEASURED AT THE MAXIMUM
SOLDER BALL DIAMETER PARALLEL TO DATUM
PLANE Z.
DATUM Z IS DEFINED BY THE SPHERICAL
CROWNS OF THE SOLDER BALLS.
PARALLELISM MEASUREMENT SHALL EXCLUDE
ANY EFFECT OF MARK ON TOP SURFACE OF
PACKAGE.
0.8 1
0.2 0.3
0.22 REF
0.45 REF
0.35
8 BSC
8 BSC
0.65 BSC
6.5 BSC
6.5 BSC
VFBGA 96 BALLS
8X8X1mm
(JEDEC MO-225)
b
UNIT
MM
L
A
B
C
D
E
F
G
H
J
K
L
BC212015EN and 6x6x1mm VFBGABC212013EN
BC212015DN and 8x8x1mm VFBGABC212013DN
Page 18 of 21
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Interface Version Shipment Method
USB and UART Tray (dry pack)
UART only Tape and reel
UART only Tray (dry pack)
Order Number
BC212015ADN-E4
BC212015ADN-Y1
BC212013ADN-E4
BC212013ADN-Y1
USB and UART Tape and reel
Ordering and Contact Information
Contact CSR Worldwide
To contact a CSR representative, please go to www.csr.com/contacts.htm
CSR Japan
CSR KK
Miyasaka LK Building 3F
43-23, 3 Chome Shimorenjaku
Mitaka-shi, Tokyo
Japan 181-0013
Tel: +81 (0) 422 40 4760
Fax: +81 (0) 422 40 4765
e-mail: sales@csr.com
CSR Head Office
Cambridge Science Park
Milton Road
Cambridge, CB4 0WH
United Kingdom
Tel: +44 (0) 1223 692 000
Fax: +44 (0) 1223 692 001
e-mail: sales@csr.com
CSR USA
1651 N. Collins Blvd.
Suite 210
Richardson
TX75080
USA
Tel: +1 972 238 2300
Fax: +1 972 231 1440
e-mail: sales@csr.com
CSR Denmark
Novi Science Park
Niels Jernes Vej 10
9220 Aalborg East
Denmark
Tel: +45 72 200 380
Fax: +45 96 354 599
e-mail: sales@csr.com
CSR Singapore
Blk 5, Ang Mo Kio
Industrial Park 2A
AMK Tech II, #07-08
Singapore 567760
Tel: +65 484 2212
Fax: +65 484 2219
e-mail: sales@csr.com
Ordering and Contact Information
Packaging Options: 2Kpcs Taped & Reeled (E4)
348pcs Tray (5 Trays to a box) (Y1)
USB and UART Tray (dry pack)
UART only Tape and reel
UART only Tray (dry pack)
BC212015AEN-E4
BC212015AEN-Y1
BC212013AEN-E4
BC212013AEN-Y1
USB and UART Tape and reel
Package
8x8x1mm
8x8x1mm
8x8x1mm
8x8x1mm
6x6x1mm
6x6x1mm
6x6x1mm
6x6x1mm
Page 19 of 21
CSR Korea
#104-404, Kukje Sanjang Apt
Shinlim 10-Dong, Kwanak-Ku
Seoul 151-767,
Korea
e-mail: sales@csr.com
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
The progression of CSR Product Data Sheets follows the following format:
a) Advance Information
Information for designers on the target specification for a CSR product in development.
All detailed specifications including pinouts and electrical specifications may be changed by CSR without
notice.
b) Pre-Production Information
Final pinout and mechanical dimensions. All electrical specifications may be changed by CSR without notice.
c) Production Information
Final Data Sheet including the guaranteed minimum and maximum limits for the electrical specifications.
Production Data Sheets supersede all previous document versions.
The status of this Data Sheet is Pre-Production Information.
Status of Information
Status of Information
Trademarks, Patents and Licenses
BlueCore and BlueLab are trademarks of CSR.
Bluetooth and the Bluetooth logos are trademarks owned by Bluetooth SIG Inc, USA and licensed to CSR.
All other product, service, and company names are trademarks, registered trademarks, or service marks of
their respective owners.
The publication of this information does not imply that any license is granted under any patent or other rights
owned by CSR.
CSR reserves the right to make technical changes to its products as part of its development programme.
While every care has been taken to ensure the accuracy of the contents of this document, CSR cannot accept
responsibility for any errors.
CSR Ltd 2001
Life Support Policy and Use in Safety-Critical Applications
CSR’s products are not authorised for use in life-support or safety-critical applications.
Page 20 of 21
BlueCore 2-External Product Data Sheet
TM
BC212015-ds-001b
Product Data Sheet
Pre-Production Information
Date: Revision: Reason for Change:
September 2001 aLatest information for BlueCore2-External
BlueCore2-External Product Data Sheet
BC212015-ds-001b
October 2001
October 2001 bApplication information added
Page 21 of 21
