ZHCSTD7A December 2021 – November 2023 BQ79631-Q1
PRODUCTION DATA
Thermal shutdown occurs when the thermal shutdown sensor senses an overtemperature condition of the device. The sensor operates without interaction and is separated from the ADC measured die sensor. The thermal shutdown function has a register-status indicator flag (FAULT_SYS[TSHUT]) that is saved during the shutdown event and can be read after the device is awaken back up. When a TSHUT fault occurs, the part immediately enters the SHUTDOWN mode. Any pending transactions on UART or daisy-chain are discarded. There is no fault signaling performed when a thermal shutdown event occurs as the device immediately shuts down.
To awaken the device, host ensures the ambient temperature is below TSHUT_FALL and sends a WAKE ping to the base device. Host will not attempt to wake the device if the ambient temperature is still above TSHUT_FALL.
Upon waking up, the FAULT_SYS[TSHUT] bit is set. The FAULT_SYS[SHUTDOWN_REC] = 1 indicating the prior shutdown is caused by abnormal event. See Section 8.4.1.1 for more details. If the system faults are unmasked, FAULT_MSK1[MSK_SYS] = 0, the thermal shutdown will be reflected as a fault and will be indicated in the FAULT_SUMMARY register and the assertion of the NFAULT pin.