Hi
I am using Control Card RM46L852 MCU which has TPS65381 chip. I would like to know if the MCU boot is due to a board cold boot, a reset watchdog or a MCU ERROR/WDI pin error.
After a reset is caused by MCU ERROR/WDI MCU pin I can see that the value DEV_ERR_CNT is incremented (this is normal). However ERROR_PIN_FAIL in SAFETY_ERR_STAT register value is 0 (it doesn't seem right for me). If I switch SW1 to disable MCU PORRST I can read ERROR_PIN_FAIL with value at 1. Why when MCU reset is enabled the clear ERROR_PIN_FAIL bit is cleared ? I have checked that the MCU doesn't clear that bit when configuring the TPS.
To identify watchdog reset I read WDT_FAIL_CNT at MCU start up. I am quite amazed that WDT_FAIL_CNT = 7 at cold reboot (pressing S2 switch). When the reboot is caused by a watchdog reset or ERROR/WDI pin error I can read WDT_FAIL_CNT = 7. TPS datasheet says "The default value is 5, and is initialized to this value upon entering DIAGNOSTIC and ACTIVE state". Why can I read WDT_FAIL_CNT = 7 at startup (in diagnostic mode) ? Is it reliable to determine reset cause ?
Thanks,
Thomas
