SLUUBD4A April 2016 – November 2022 BQ27220
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 (fSCL) 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. A DF_CHECKSUM() subcommand requires 100 ms minimum prior to reading the result. For read-write standard command, a minimum of 2 s is required to get the result updated. For read-only standard commands, there is no waiting time required, but the host should not issue all standard commands more than two times per second. Otherwise, the fuel gauge could result in a reset issue due to the expiration of the watchdog timer.