Not understanding IWDG and HAL in STM32F7

[RCres.1]

Hi,

I am trying to get working IWDG using HAL_IWDG library and I am not able to refresh the watchdog before IWDG_Reset.

As is said in page 6: (https://www.st.com/content/ccc/resource/training/technical/product_training/group0/01/24/22/29/38/70/40/57/STM32WB-WDG_TIMERS-Independent-Watchdog-IWDG/files/STM32WB-WDG_TIMERS-Independent-Watchdog-IWDG.pdf/_jcr_content/translations/en.STM32WB-WDG_TIMERS-Independent-Watchdog-IWDG.pdf

I must refresh watchdog when RL < WINR

Watchdog timeout is set to 10s. wdgReset() is called from main loop, which I know is not consuming 10s.

MCU has a reset every 10s as a consequence

IWDG_HandleTypeDef t_wdg;
 
void wdgInit(void){
	
   t_wdg.Instance = IWDG;	
   t_wdg.Init.Prescaler = IWDG_PRESCALER_256; 
   t_wdg.Init.Reload = 1250;
   t_wdg.Init.Window = 1250;	
   HAL_IWDG_Init(&t_wdg);
 
}
 
void wdgReset(void){
	if(t_wdg.Instance->RLR < t_wdg.Init.Window){
		HAL_IWDG_Refresh(&t_wdg);
	}	
}

What I am missing?

Kind Regards,

Rafa

[waclawek.jan]

Check, if the refresh executes at all (e.g. toggle a pin next to it and observe that pin using oscilloscope or LA).

Try refreshing it unconditionally.

JW

[TDK]

The problem is almost certainly that your main loop is not actually calling wdgReset.

[TDK · Accepted solution]

> t_wdg.Init.Reload = 1250;

Okay so RLR = 1250.

> t_wdg.Init.Window = 1250;

Okay, Window is also 1250.

> if(t_wdg.Instance->RLR < t_wdg.Init.Window){

How will this ever execute? You're not really using the window functionality. Just get rid of it and this check and call HAL_IWDG_Refresh unconditionally.

[RCres.1]

Wow...this was a huge mistake.....Now is working

Thanks