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Original question:

TPS3820-Q1: If the MCU keeps the WDI pin high..

TPS3820-Q1: DWI = High when /RESET = Low

Yuta Nishie
Genius 3280 points
Part Number: TPS3820-Q1
Other Parts Discussed in Thread: TPS3820

Hi,

My question is about TPS3820(non-Q1).

If DWI is fixed at High when/RESET=Low(Active), is there a problem with the device?

I think there is no problem, is this correct?

Best Regards,

Nishie

  • +1
    TI__Expert 5490 points

    Hi Nishie,

    When you state "DWI" are you referring to the watchdog timer input, WDI?

    For watchdog timer input (WDI), if it is fixed at high or low longer than the time-out period, then a reset will be triggered. When a reset is triggered the watchdog timer is reinitialized.

    In your case as long as WDI is fixed at high during a RESET and then resumes normal positive or negative transitions when RESET is not active (when the watchdog is reinitialized) there should be no problem.

    Thanks,

    Joshua 

  • 0 in reply to Joshua Garcia
    Genius 3280 points

    Hi Joshua-san,

    Thank you for your reply.

    I'm sorry. My mistake.
    DWI means WDI.

    Joshua Garcia said:
    when RESET is not active (when the watchdog is reinitialized)

    ->Is it correct that the watchdog timer is reinitialized after td?

    Joshua Garcia said:
    In your case as long as WDI is fixed at high during a RESET and then resumes normal positive or negative transitions when RESET is not active (when the watchdog is reinitialized) there should be no problem.

    ->In other words, if it is between td, is it OK to fix WDI= High?

    Best Regards,

    Nishie

  • +1 in reply to Yuta Nishie
    TI__Expert 5490 points

    Hi Nishie,

    Yuta Nishie said:
    I'm sorry. My mistake.
    DWI means WDI

    No worries!

    Yuta Nishie said:
    >Is it correct that the watchdog timer is reinitialized after td?

    Yes that is correct. 

    Yuta Nishie said:
    ->In other words, if it is between td, is it OK to fix WDI= High?

    As you stated, it is OK to fix WDI high during delay time, td. Just be aware of the accuracy of the delay time (Section 7.8 Switching Characteristics of datasheet) to ensure normal positive or negative transitions after reinitialization.

    Thanks,

    Joshua

  • 0 in reply to Joshua Garcia
    Genius 3280 points

    Hi Joshua-san,

    Thank you for your reply.

    I understand!

    Best Regards,

    Nishie