BQ27532-G1 Datasheet, PDF (18/35 Pages) Texas Instruments – Battery Management Unit Impedance Track Fuel Gauge

bq27532-G1
SLUSBU6B – SEPTEMBER 2014 – REVISED JANUARY 2016
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7.5.3 Charger Data Commands
The charger registers are mapped to a series of single-byte Charger Data Commands to enable system reading
and writing of battery charger registers. During charger power up, the registers are initialized to Charger Reset
State. The fuel gauge can change the values of these registers during the System Reset State.
Each of the bits in the Charger Data Commands can be read or write. Note that System Access can be different
from the read or write access as defined in bq2425x charger hardware. The fuel gauge may block write access to
the charger hardware when the bit function is controlled by the fuel gauge exclusively. For example, the
[VBATREGx] bits of Chrgr_Reg2 are controlled by the fuel gauge and cannot be modified by system.
The fuel gauge reads the corresponding registers of Chrgr_Reg0( ) and Chrgr_Reg2( ) every second to mirror
the charger status. Other registers in the bq2425x device are read when registers are modified by the fuel gauge.
NAME
ChargerStatus( )
Chrgr_Reg0( )
Chrgr_Reg1( )
Chrgr_Reg2( )
Chrgr_Reg3( )
Chrgr_Reg4( )
Chrgr_Reg5( )
Chrgr_Reg6( )
CHGRSTAT
CHGR0
CHGR1
CHGR2
CHGR3
CHGR4
CHGR5
CHGR6
Table 3. Charger Data Commands
COMMAND
CODE
0x32
0x33
0x34
0x35
0x36
0x37
0x38
0x39
bq2425x CHARGER
MEMORY LOCATION
NA
0x00
0x01
0x02
0x03
0x04
0x05
0x06
SEALED
ACCESS
R
RW
RW
RW
RW
RW
RW
RW
UNSEALED
ACCESS
R
RW
RW
RW
RW
RW
RW
RW
REFRESH
RATE
Every second
Every second
Data change
Every second
Data change
Every second
Data change
Data change
7.5.4 Communications
7.5.4.1 I²C Interface
The fuel gauge supports the standard I²C read, incremental read, quick read, one-byte write, and incremental
write functions. The 7-bit device address (ADDR) is the most significant 7 bits of the hex address and is fixed as
1010101. The first 8 bits of the I²C protocol are, therefore, 0xAA or 0xAB for write or read, respectively.
Host generated
Gauge generated
S ADDR[6:0] 0 A CMD [7:0] A DATA [7:0] A P
S ADDR[6:0] 1 A DATA [7:0]
(a) 1-byte write
(b) quick read
S ADDR[6:0] 0 A CMD [7:0] A Sr ADDR[6:0] 1 A DATA [7:0] N P
(c) 1- byte read
NP
S ADDR[6:0] 0 A
CMD [7:0]
A Sr ADDR[6:0] 1 A
(d) incremental read
DATA [7:0]
A ...
DATA [7:0]
NP
S ADDR[6:0] 0 A CMD[7:0] A DATA [7:0] A DATA [7:0]
(e) incremental write
(S = Start , Sr = Repeated Start , A = Acknowledge , N = No Acknowledge , and P = Stop).
Figure 8. I²C Interface
A ... A P
The quick read returns data at the address indicated by the address pointer. The address pointer, a register
internal to the I²C communication engine, increments whenever data is acknowledged by the fuel gauge or the
I²C master. “Quick writes” function in the same manner and are a convenient means of sending multiple bytes to
consecutive command locations (such as two-byte commands that require two bytes of data).
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