SLUS724F September 2006 – January 2022
PRODUCTION DATA
It may be necessary to “bit-bang” a GPIO on the host system to act as the SDQ master. In this case, some additional error checking should be built into the code used to reset the BQ2022A to ensure that the slave is operating as expected on the bus.
Whenever the host sends a reset, the BQ2022A responds with a presence pulse. The host should confirm, before the presence pulse, that the bus has been released and returned to a high level, indicating that nothing is holding the bus unexpectedly low. As the minimum tppd is 15 µs, having the host look for a logic high on the bus 10 µs after releasing the bus at the end of the reset is sufficient to confirm the bus is released for the BQ2022A to respond.