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TPS65381-Q1: WatchDog IN from Hercules TMS570x

Part Number: TPS65381-Q1

SPNA176A–February 2014...Figure 1. Example TPS65381 With Texas Instruments TMS570/RM4x

shows the nERROR siignal from the HERC going to he WDI/ERROR pin of the TPS65381.

Is this ok if using TRIGGER mode?....

I have been using the TRIGGER mode of the TPS65381  (not the Q&A mode) and driving the ERROR,WDI pin of the TPS65381 with a GPIO pin of a few different Microprocessors, ( basically setting the uP to interrupt on a specifiic time and then synching the uP to the TPS65381)...that works fine...

the nERROR pin on the Herc appears to be a pin that will "flagg error, i.e. go LOW), if something internal in the Herc goes wrong (i.e. voltage level off, etc etc)....

just want to make sure I can use that nERROR pin as a WD pulse to the TPS65381. (i.e. set a timer interrupt in the Herc and then pulse that nERROR pin with a pulse  that meets the Window/1 WINDOW 2 timing  of the TPS65381)..

thank you  or any insight!....

cheers

jyoung@dcscorp.com

  • Hi Mr. Young,

     Yes, you can use Trigger Mode (Default Mode) When the device goes from the RESET state to the DIAGNOSTIC state, the watchdog operates in trigger mode (default). The first watchdog sequence begins with the default tWIN1 and tWIN2 time periods. The watchdog receives the triggers from the MCU on the ERROR/WDI pin. A rising edge on the ERROR/WDI pin, followed by a falling edge on the ERROR/WDI pin after more than the required pulse time, tWD_pulse(max) (32 μs), is a trigger. Even a waveform with a longer duration high than low is counted as a trigger if the rising and falling edges meet this requirement.

    Thanks!

    Phil

  • Phil,

    thanks...

    yes  I understand that portion of it...

    the question is: in the attached pic, (from Application Report
    SPNA176A–February 2014...page 3 figure 1)

    it shows the "nERROR" signal from the Hercules driving the ERRIR/WDI pin of the TPS65381.

    I wasnt  sure if that nERROR pin on the Herc has the ability to be configured as a Watchdog output trigger to the TPS65381...(the herc docs describe that  pin/function as a fault trigger output)....

    just wondering if using a GPIO to generate the WD makes more sense...

    if above makes sense

  • Hi Mr. Young,

      Can you check with Herc Apps if the nERROR pin on the Herc has the ability to be configured as a Watchdog output trigger?

      For the PMIC, it's ok as long as the trigger input meets the requirement. I think using a GPIO to generate the WD makes more sense if not sure the nERROR pin on the Herc has the ability to be configured as a Watchdog output trigger.

    Thanks!

    Phil