TPS65381-Q1 MCU_ERR and ERROR_PIN_FAIL, WD_ERR and WD_FAIL

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Hi Shimizu-san,

I want to look deeper into this early next week.  Thanks for the patience.

- Scott

Hi Shimizu-san,

A1)    The main reason there are similiar registers it to preserve the fucntionality of the feature while BIST is running (ie if it is activated during operation for some safety requirement specific to the application). One of these bits is in the core covered by BIST, but the other is not in BIST so if the MCU Error happens the fault detection and actions will be immediate (ie ENDRV will disable) even if BIST is running. The other uses can be: SAFETY_STAT_4/MCU_ERR(Read Only)  flag indicates a failure of the MCU to meet the requirments of the ESM (ie wrong timing, lack of PWM, etc) on on the error pin.  This flag may be monitored during diagnostic state to ensure the MCU error funciton is working properly or the MCU could also intentionally inject a fault on the error pin and then read this register to ensure the fault dectection and the PCB connections are okay. The SAFETY_ERR_STAT/ERROR_PIN_FAIL(R/W) is the flag once the MCU Error Signal Montoring has been enabled to allow the device to move to the safe state when there is an error pin fault in active state.

A2) Like A1) these are redundant flags, one is covered by BIST and is not updated while BIST is running, the other retains its state and will allow response immediately even if BIST is running.

- Scott