STM32F107 IWDG does not make a reset

[hhosburg]

Posted on December 12, 2011 at 16:08

Hello,

I'm using the ST libraries to initialize the IWDG  with following code:

 IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);

  IWDG_SetPrescaler(IWDG_Prescaler_128);

  IWDG_SetReload(0x400);

  IWDG_ReloadCounter();

  IWDG_Enable();

after 3 seconds the watchdog should make an reset, but the reset fails (no watchdog timeout).

I have tested the code on an other board (different hardware) with the same cpu,  and on this hardware the IWDG reset is working

does anyone have any idea ?

 Thanks,

Harald

[Tesla DeLorean]

Posted on December 12, 2011 at 16:35

does anyone have any idea ?

 

Without looking at the board, one might guess that the reset pin is clamped high (driven by an external push-pull driver), and thus can't reset.

If LSI wasn't working, it would be a problem, but with IWDG enabled you shouldn't be able to turn off the LSI.

It might be possible to alter the IWDG with some of the debugger options.

[hhosburg]

Posted on December 12, 2011 at 18:44

Thanks,

yes, there were placed the wrong resistors on  reset circuit. After changing to the correct values  the IWDG is working as expected.

Harald