BQ27510_08 Datasheet, PDF (30/36 Pages) Texas Instruments – System-Side Impedance Track™ Fuel Gauge With Direct Battery Connection

bq27510
SLUS816A – MARCH 2008 – REVISED JUNE 2008.......................................................................................................................................................... www.ti.com
COMMUNICATIONS
I²C INTERFACE
The 27510 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 8-bit device address will therefore be 0xAA or 0xAB for write or read, respectively.
Host generated
bq27510 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] N P
(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
S ADDR[6:0] 0 A CMD[7:0] A Sr ADDR[6:0] 1 A DATA[7:0] A . . . DATA[7:0] N P
(d) incremental read
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 4. Supported I²C Formats
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, will increment whenever data is acknowledged by the bq27510 or the
I2C master. “Quick writes” function in the same manner and are a coS = Start, Sr = Repeated Start, A =
Achnowledge, nvenient means of sending multiple bytes to consecutive command locations (such as two-byte
commands that require two bytes of data)
The following command sequences are not supported:
Attempt to write a read-only address (NACK after data sent by master):
S ADDR[6:0] 0 A CMD[7:0]
A DATA[7:0]
AP
Attempt to read an address above 0x6B (NACK command):
S
ADDR[6:0]
0 A CMD[7:0] N P
The I²C engine will release both SDA and SCL if the I2C bus is held low for t_(BUSERR). If the bq27510 was holding
the lines, releasing them will free the master to drive the lines. If an external condition is holding either of the
lines low, the I²C engine will enter the low power sleep mode.
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