STM32U5 sometimes does not reconfigure IWDG.

[Sheller]

At startup, I set the watchdog timer to 8 seconds.

IWDG->KR = IWDG_KEY_ENABLE;
IWDG->KR = IWDG_KEY_WRITE_ACCESS_ENABLE;
IWDG->PR = IWDG_PRESCALER_64; // 8 s
IWDG->KR = IWDG_KEY_WRITE_ACCESS_DISABLE;

Further, in the interrupt, when the button is pressed, I want to reconfigure for a shorter duration and reset the processor.

IWDG->KR = IWDG_KEY_WRITE_ACCESS_ENABLE;
IWDG->PR = IWDG_PRESCALER_32;
IWDG->RLR = 429;
while(IWDG->SR){};
IWDG->KR = IWDG_KEY_RELOAD;
while(true){} 

Everything works, but sometimes the reset occurs not after 430 ms, but after 4 seconds. In this case, the desired values ​​are written in the IWDG registers. The connected debugger does not affect the result, the same thing is repeated with and without the connected debugger.

[Mohamed Aymen HZAMI]

Hello @Sheller​ and welcome to the community,

Can you please share your code ?

Aymen