Data Sheet
A AS 0ADDR [6:0] CMD [7:0] Sr 1ADDR [6:0] A DATA [7:0] A DATA [7:0] PN
A AS A0 PADDR [6:0] CMD [7:0] DATA [7:0] DATA [7:0] A 66 sm
A AS 0ADDR [6:0] CMD [7:0] Sr 1ADDR [6:0] A DATA [7:0] A DATA [7:0] A
DATA [7:0] A DATA [7:0] PN
Waiting time inserted between incremental 2-byte write packet for a subcommand and reading results
(acceptable for 100 kHz)f
SCL
£
Waiting time inserted after incremental read
66 sm
66 sm
A AS 0ADDR [6:0] CMD [7:0] Sr 1ADDR [6:0] A DATA [7:0] A DATA [7:0] PN
A AS A0 PADDR [6:0] CMD [7:0] DATA [7:0] 66 sm
Waiting time inserted between two 1-byte write packets for a subcommand and reading results
(required for 100 kHz < f 400 kHz)
SCL
£
66 sm
A AS A0 PADDR [6:0] CMD [7:0] DATA [7:0] 66 sm
bq27441-G1
SLUSBH1C –NOVEMBER 2013–REVISED DECEMBER 2014
www.ti.com
9.5.4.3 I
2
C Command Waiting Time
To ensure proper operation at 400 kHz, a t
(BUF)
≥ 66 μs bus-free waiting time must be inserted between all
packets addressed to the fuel gauge. In addition, if the SCL clock frequency (f
SCL
) is > 100 kHz, use individual 1-
byte write commands for proper data flow control. The following diagram shows the standard waiting time
required between issuing the control subcommand the reading the status result. For read-write standard
command, a minimum of 2 seconds is required to get the result updated. For read-only standard commands,
there is no waiting time required, but the host must not issue any standard command more than two times per
second. Otherwise, the gauge could result in a reset issue due to the expiration of the watchdog timer.
9.5.4.4 I
2
C Clock Stretching
A clock stretch can occur during all modes of fuel gauge operation. In SLEEP and HIBERNATE modes, a short ≤
100-µs clock stretch occurs on all I
2
C traffic as the device must wake-up to process the packet. In the other
modes (INITIALIZATION, NORMAL), a ≤ 4-ms clock stretching period may occur within packets addressed for
the fuel gauge as the I
2
C interface performs normal data flow control.
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