[ Electron ] : How can i use the hardware watchdog of the STM32F205?

Firmware
10

Hello everybody,

I’m also trying to use the IWDG. Looking into the firmware I found this file “stm32f2xx_iwdg.h”

Using it in a simple example:

  • after 30 sec config and enable WD
  • with while(1){IWDG_ReloadCounter();} no reset
  • without while(1){IWDG_ReloadCounter();} reset after ~1040ms
  • using IWDG_Prescaler_256 or IWDG_Prescaler_4 does not change the reset period so I’m probably doing something wrong. I wanted to go for the maximum period between resets (~=32 sec) I also added the delays but do not know if it is needed?
#include "stm32f2xx_iwdg.h"

SYSTEM_THREAD(ENABLED);

void setup()
{
    Serial.begin(115200);
}

static unsigned long lastMillis = 0;
static unsigned long milPrev = 0;
static uint8_t t = 0;
static uint8_t once = 1;

void loop()
{
    if(!once)
    {
        unsigned long mil = millis() - lastMillis;
        if((mil-milPrev) > 1 ) // count 2ms untill WD reset
        {
            Serial.printlnf(" %lu",millis() - lastMillis);
            milPrev = mil;
        }
    }
    
    
    if(((millis() - lastMillis) > 1000) && once) 
    {
        t++;
        Serial.printlnf("t=%u",t);
        if(once && t==30)
        {
            once = 0;
            
            Serial.println("WD config");
            // 1. Enable write access to IWDG_PR and IWDG_RLR registers using
            //    IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable) function*/
            IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
            
            // 2. Configure the IWDG prescaler using IWDG_SetPrescaler() function
            delay(500);
            IWDG_SetPrescaler(IWDG_Prescaler_256);
            delay(500);
            
            // 3. Configure the IWDG counter value using IWDG_SetReload() function.
            //    This value will be loaded in the IWDG counter each time the counter
            //    is reloaded, then the IWDG will start counting down from this value.
            delay(500);
            IWDG_SetReload(0xFFF);
            
            // 4. Start the IWDG using IWDG_Enable() function, when the IWDG is used
            //    in software mode (no need to enable the LSI, it will be enabled by hardware)
            delay(500);
            
            uint8_t pvu = IWDG_GetFlagStatus(IWDG_FLAG_PVU) == SET;
            Serial.printlnf("pvu %u", pvu);
            uint8_t rvu = IWDG_GetFlagStatus(IWDG_FLAG_RVU) == SET;
            Serial.printlnf("rvu %u", rvu);
            delay(500);
            Serial.println("Reload");
            IWDG_ReloadCounter();
            
            delay(500);
            Serial.println("WD enable");
            IWDG_Enable();
            
            // 5. Then the application program must reload the IWDG counter at regular
            //    intervals during normal operation to prevent an MCU reset, using
            //    IWDG_ReloadCounter() function.

            //while(1){IWDG_ReloadCounter();}
        }
        
        lastMillis = millis();
    }
    
}

So it seems that the IWDG is working?
Why is it officially not working? What am I missing?
I do not plan to use Sleep in my application. Should I be careful with other things (OTA?)

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