Microcontroller debug unit on STM32H753

[seb536]

Hello,

I'm having an issue to use the Microcontroller debug unit (DBGMCU) on STM32H753.

I have got IWDG set up and working as expected and would like to have the IWDG frozen during debugging.

I have set the DBG_IIWDG1 (bit 18) of register DBGMCU_APB4FZ1 to 1 but that doesn't seem to have any effect as the watchdog still runs and reset in debug mode.

My initialisation sequence is:

 - Enable LSI Clck

 - Freeze IWDG In Debug Mode (DBG_IIWDG1)

 - Enable IWDG (WDG_KR)

 - Enable Write Access (WDG_KR)

 - Set Prescaler (WDG_PR)

 - Set Reload Counter (WDG_RLR)

I couldnt find any examples in STMCube related to the Microcontroller debug unit. Please could you help ?

Thanks

Seb

[Sarra.S]

Hello @seb536, welcome to ST Community,

Add  __HAL_RCC_DBGMCU_CLK_ENABLE() before calling HAL_DBGMCU_FREEZE_IWDG or  setting  the DBG_IIWDG1 bit in DBGMCU_APB4FZ1 (it's basically the same thing)