Maximum Watchdog Time-Out

[charles2399]

Posted on January 27, 2009 at 18:09

Maximum Watchdog Time-Out

[charles2399]

Posted on May 17, 2011 at 13:00

Reading RM0008 it seems that the maximum time-out for the watchdog timer is 58 ms. Is that correct? Can it be expanded to 1 or 2 seconds?

This is a very small value, most other products give a much broader range of values. We have library functions that take more than 58 ms, and with this short time-out value we will have sprinkle watchdog hits into the library functions. Servicing the watchdog in an intterupt seems to defeat the function.

[charles2399]

Posted on May 17, 2011 at 13:00

Thanks, I had overlooked the IWDG and focusing on the WWDB.

[trevor1]

Posted on May 17, 2011 at 13:00

The max is 26 seconds not 58mS. I use this:

Code:

static void start_watchdog(void)

{

RCC_LSICmd( ENABLE ); // enable low speed internal clock used by watchdog

while (IWDG->SR & 0x3); // wait for previos update operations to complete

IWDG->KR = 0x5555; // Enable independent watchdog register access

IWDG->PR = 6; // prescaller set to divice by 256 (min 6.4ms, max 26214.4ms)

IWDG->RLR = 0xFFF; // reload value (0xFFF max)

IWDG->KR = 0xCCCC; // start the watchdog

}

void stroke_watchdog(void)

{

IWDG->KR = 0xAAAA;

}

Regards

Trevor