BQ27000 Datasheet, PDF (26/29 Pages) Texas Instruments – SINGLE CELL Li-Ion AND Li-Pol BATTERY GAS GAUGE IC FOR PORTABLE APPLICATIONS (bqJUNIOR)

bq27000, bq27200
SLUS556B – SEPTEMBER 2004 – REVISED NOVEMBER 2004
¡¡ _{Host generated}
bq27200 generated
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ _{S ADDR[6:0]}
0A
CMD[7:0]
(a)
¡¡¡¡¡¡ ¡¡¡¡¡ ¡¡¡¡¡¡¡ _{S ADDR[6:0]}
0A
¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ ¡¡ _{S ADDR[6:0]}
0A
CMD[7:0]
A
DATA[7:0]
AP
S
CMD[7:0]
A Sr
(c)
ADDR[6:0]
ADDR[6:0]
1A
(b)
1A
DATA[7:0]
A Sr ADDR[6:0]
1A
DATA[7:0]
A ...
(d)
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DATA[7:0]
¡¡¡¡¡¡_{N P}
DATA[7:0]
¡¡¡¡
NP
¡¡_N ¡¡_P
Figure 7. Supported I2C formats :
(a) 1-byte write; (b) quick read; (c) 1-byte read; (d) incremental read
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 bq27200 or the I²C
master.
Due to the memory map setup of the device, several boundary conditions must be enforced by the
communication engine.
¡¡¡¡¢¢¢¢¢¢¡¡ ¡¡¢¢¢¢¢¢¢¢ ¡¡¢¢¢¢¢¢¢¢¢¢¡¡ ^{Attempt to write a read-only address (NACK after data sent by master):}
S ADDR[6:0]
0A
CMD[7:0]
A
DATA[7:0]
NP
¡¡¡¡¢¢¢¢¢¢¡¡ ¡¡¢¢¢¢¢¢¢¢ ¡¡ ^{Attempt to read an address above 0x7F (NACK command):}
S ADDR[6:0]
0A
CMD[7:0]
NP
¡¡¡¡¡¡¡¡¡¡¡¡ ¡¡¡¡¡¡¡¡ ¡¡¡¡¡¡¡¡¡¡ ¡¡¡¡¡¡¡¡¡¡¡¡¡¡ ¡¡ ^{Attempt at incremental writes (NACK all extra data bytes sent):}
S ADDR[6:0] 0 A
CMD[7:0]
A DATA[7:0]
A DATA[7:0]
N ... N P
¡¡¢¢¢¢¢¢¡¡¡¡¢¢¢¢¢¢¢¢¡¡¡¡¢¢¢¢¢¢ ^{Incremental read at the maximum allowed read address:}
¡¡ ¡¡¡¡
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
Address
0x7F
Data from
addr 0x7F
Data from
addr 0x00
The I²C engine releases both SDA and SCL if the I²C bus is held low for T_(BUSERR). If the bq27200 was holding
the lines, releasing them frees the master to drive the lines. If an external condition is holding either of the lines
low, the I²C engine enters the low-power sleep mode if the measured charge and discharge activity level are less
than the DMF threshold.
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