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STM32F4 IWDG keeps resetting even though key register is written with 0xAAAA

Question asked by wiessner.alexander on Jul 30, 2015
Latest reply on Jul 31, 2015 by wiessner.alexander
I have the following issue with the IWDG:
I initialized the IWDG with the sequence
  IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
  IWDG_SetPrescaler(IWDG_Prescaler_32);
  IWDG_SetReload(0x0FF0);
  IWDG_ReloadCounter();
  IWDG_Enable();
which will cause a timeout after 4 seconds, and then I reset the counter periodically with
  IWDG_ReloadCounter();
which writes 0xAAAA to the key register. However, the watchdog always resets the system after 4 seconds, as if the call to IWDG_ReloadCounter() never took place (the debugger tells otherwise). What could be the issue?


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