TPS65381-Q1 4-bit watchdog answer counter (207)

This 4-bit description is in error in this section. It is the 2-bit (or 4 counter option) WDT_ANSW_CNT described in section 5.4.1.14.3.1 on page 52 of the datasheet.

- Scott

Hello Scott-san,

Thank you for your reply.
Please answer following questions again.


1) Please explain the meaning of “(or 4 counter option)” you said in your answer.

2) In case of 4-bit counter is WDT_ANSW_CNT, following description of page 53 is Incomprehensible, because WDT_ANSW_CNT decrease by one when one token response is written by MCU as explained in page 52.

• If the answer was correct in value (TOKEN_ERR = 0) and Timing:
– The 4-bit watchdog answer counter increases by one

Please confirm what is 4-bit counter again.

3) Page 49 has 4-bit counter too, and I can’t understand following explanation.

“The Markov chain is clocked by the 4-bit counter at the transition from 1111 bin 0000 bin.”

I believe Markov chain should be clocked after receive of 4 correct answer in correct window to generate new TOKEN value, but it needs 16 correct answer in correct window to clock the Markov chain in case of counter is 4-bit.

Is this 4-bit counter is same with page 53?
Is 4-bit counter correct?

Best Regards.

1) 4 counter option = 2 bits = 4 counts which could be 0 (b00), 1 (b01), 2 (b10) or 3 (b11).
2) Counter is WDT_ANSW_CNT --> this counter indicate where you are in the QA response sequence and which WD_TOKEN_RESP_x is expected next.
3) There is a seperate 4 bit WDT Token Counter shown in Figure 5-10 used with the Markov chain.

I will work with the systems team in the new year to try to clean up the documentation and provide a more clear description of the QA WDT and how to use it.

- Scott

Hello Scott-san,

Thank you for your answer.

Please let me known the schedule of clean up the documentation and provide a more clear description of the QA WDT and how to use it.

I think it is difficult to understand QA WDT behavior using existing datasheet so want new documentation as soon as possible to support customer.

Best Regards.

Hi Ushikubo-san,

The target is datasheet clean up by end of January after all the necessary review cycles and then possibly a seperate app note in 1Q on the Q&A watchdog.

- Scott

Hell Scott-san,

Customer has to finish all software by this March so they need these information as soon as possible.

So please send me when you make draft of datasheet and App note, and advice draft schedule.

Best Regards.

Hello Scott-san,

Please answer above my request.

Best Regards.

The answer is above "The target is datasheet clean up by end of January after all the necessary review cycles and then possibly a seperate app note in 1Q on the Q&A watchdog.

- Scott

Hello Scott-san,

Please advise latest status of datasheet clean up.

Best Regards.