TPS65381A-Q1: Watchdog new sequence

Hi Yusup,

A new sequence is started after the watchdog receives either a good event or bad event (4 answers within the sequence) or timeout event.  In your case, sending bad answer bytes will mean that while the answers will be detected with the wrong answer byte even at the first byte (Resp3) sent, the watchdog waits for the 4th answer (Resp0) within the sequence to finish the timing portion of the watchdog requirement. Immediately after the 4th answer-byte (Resp3) the watchdog will detect this as a bad event and start a new watchdog sequence.   In similar fashion if the 4 answer bytes were correct in value and Resp3 is in window2 of the sequence it would be detected as a good event and a new sequence starts immediately after Resp3 again.  If the watchdog doesn't receive 4 answer bytes within the sequence, the watchdog detects a timeout (no response or incomplete set of answers from the MCU) and the new sequence starts immediately after window2 time expires in the TPS65381A-Q1.

On way to valid these are to monitor the error flags and counters for the watchdog.  In WD_STATUS register several bits help the software determine what happened if there are errors, see table 5-12 and the register map for more details.  Also, the watchdog fail counter, WD_FAIL_CNT[2:0], will immediately increment on a bad event or timeout event and it will decrement on good events.   

Best Regards,

Scott