BQ27741-G1_14 Datasheet, PDF (19/39 Pages) Texas Instruments – Single Cell Li-Ion Battery Fuel Gauge with Integrated Protection

bq27741-G1
www.ti.com
SLUSBF2 – JULY 2013
I²C Time Out
The I²C engine releases both SDA and SCL lines if the I²C bus is held low for about 2 seconds. If the fuel gauge
was holding the lines, releasing them frees the master to drive the lines.
I²C Command Waiting Time
To ensure the correct results of a command with the 400-kHz I²C operation, a proper waiting time must be added
between issuing a command and reading the results. For subcommands, the following diagram shows the
waiting time required between issuing the control command and reading the status with the exception of the
checksum command. A 100-ms waiting time is required between the checksum command and reading the result.
For read-write standard commands, 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.
xxx^xxSSxxx^xxxxx^xxAAxxx^xxDDxxx^xxDDRRxxx^xx[[66xxx^xx::00xxx^xx]] xxx^xx00xxx^xx
A
A
xxx^xxxxx^xxxxx^xxCCMMxxx^xxDDxxx^xx[[77xxx^xx::00xxx^xx]] xxx^xxxxx^xxAAxxx^xxxxx^xxSrxxx^xxDxxxxx^AATxxxxx^DADxxxxx^[7R:xxxxx^[06]xxxxx^:0]xxxxxxxx^A1xxx^{xxAxxxDxxxAxxxTDAxxxA[7xxxT:A0xxx][7xxx:0]xxxA}xxx^xxPxxx^xxAxxx
662s
DATA[7:0]
xxx^Nxxxxxx^Pxxx
662s
Waiting time between control subcommand and reading results
xxx^Sxxx_Dxxx^AAxxx^DTAxxx^D[R7xxx^[:60xxx^:]0xxx^] xxx_xxA0xxx_xx^A xxx_Dxxx_ATCxxx_AMxxx_[7Dxxx_:[07]xxx^:0]xxx_xxxxx_xxNxxx_xx^AP_xxx^xxSxxx^r xxx₆₆xxx^A₂^Dxxx_sDxxx^Rxxx^[6:xxx^0]xxxxxx¹xxx^A
xxxxxxxxx ^{DATA[7:0] A DATA[7:0]} xxx^Axxx
Waiting time between continuous reading results
The I²C clock stretch could happen in a typical application. A maximum 80-ms clock stretch could be observed
during the flash updates. There is up to a 270-ms clock stretch after the OCV command is issued.
Copyright © 2013, Texas Instruments Incorporated
Product Folder Links: bq27741-G1
Submit Documentation Feedback
19