ZHCSTD7A December 2021 – November 2023 BQ79631-Q1
PRODUCTION DATA
A WAKE ping/tone is used for the device to identify its position in the daisy-chain.
A base device will be woke up by a WAKE ping through RX pin, while a stack device will be woke up by WAKE tone via the COMH/COML port. Hence, a device is using a WAKE ping or WAKE tone to identify itself as base or stack. This information is stored in the AVAO_REF block which is available in all power modes and is refreshed whenever a WAKE ping/tone is received.
Using the CONTROL1[DIR_SEL] setting, a base device will disable the unused daisy-chain ports (transmitter and receiver). If host changes the CONTROL1[DIR_SEL] setting, the base device will reconfigure its COMH/COML.
The host starts communication at least 100 µs after changing the [DIR_SEL] setting to ensure the device finishes the COMH/COML reconfiguration.