BQ2083-V1P3 Datasheet, PDF (22/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2083-V1P3
SLVS508 − OCTOBER 2003
1
7
1
ÓÓÓÓ ÓÓÓÓ ÓÓÓÓ ÓÓÓÓ _S
Battery Address
0001011
0
1
8
1
A Command Code A
8
Data Byte Low
1
8
1
A Data Byte High A
Write Word
1
7
11
8
11
7
11
ÓÓÓÓ ÓÓÓÓ ÓÓÓÓÓÓ _S
Battery Address
0001011
0
A Command Code A
S Battery Address 1
A
www.ti.com
8
PEC
11
ÓÓÓÓ_{A P}
8
1
8
1
ÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓ _{Data Byte Low A Data Byte High A}
8
PEC
11
AP
Read Word
ÓÓÓÓ ÓÓÓÓ ÓÓÓÓ ¹
7
11
8
11
7
11
S ^{Battery Address} 0 A Command Code A S Battery Address 1 A
0001011
8
1
ÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓ ÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓ _{ByteCount= N A}
8
1
Data Byte 1 A
8
1
Data Byte 2 A
8
1
Data Byte N A
8
PEC
11
AP
Block Read
ÓÓÓÓHost Processor
bq2083
A − ACKNOWLEDGE
A − NOT ACKNOWLEDGE
S − START
P − STOP
Figure 7. SMBus Communication Protocol With PEC
PEC Calculation
The basis of the PEC calculation is an 8-bit cyclic redundancy check (CRC-8) based on the polynomial
C(X) = X8 + X2 + X1 + 1. The PEC calculation includes all bytes in the transmission, including address, command,
and data. The PEC calculation does not include ACKNOWLEDGE, NOT ACKNOWLEDGE, start, stop, and
repeated start bits.
For example, the host requests RemainingCapacity( ) from the bq2083−V1P3. This includes the host following the
read word protocol. The bq2083−V1P3 calculates the PEC based on the following 5 bytes of data, assuming the
remaining capacity of the battery is 1001 mAh.
D Battery Address with R/W = 0: 0x16
D Command Code for RemainingCapacity( ): 0x0f
D Battery Address with R/W = 1: 0x17
D RemainingCapacity( ): 0x03e9
For 0x160f17e903, the bq2083−V1P3 transmits a PEC of 0xe8 to the host.
PEC Enable in Master Mode
PEC for master mode broadcasts to the charger, host, or both can be enabled/disabled with the combination of the
bits hpe and cpe in Pack Configuration DF 0x28.
SMBus On and Off State
The bq2083−V1P3 detects whether the SMBus enters the Off State by monitoring the SMBC and SMBD lines. When
both signals are continually low for at least 2.0 s, the bq2083−V1P3 detects the Off State. When the SMBC and SMBD
lines go high, the bq2083−V1P3 detects the On State and can begin communication within 1 ms. One-MΩ pulldown
resistors on SMBC and SMBD are recommended for reliable Off State detection.
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