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Maximum Watchdog Time-Out

charles2399
Associate II
Posted on January 27, 2009 at 18:09

Maximum Watchdog Time-Out

3 REPLIES 3
charles2399
Associate II
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.

trevor1
Associate II
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

charles2399
Associate II
Posted on May 17, 2011 at 13:00

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