Can't write option byte in STM32G030

[LScha.3]

We are developing a custom board with STM32G030 and we intend to update its program through its uart with system bootloader. However, I'm unable to properly configure the option byte. The HAL_FLASHEx_OBProgram always returns HAL_ERROR or HAL_TIMEOUT.

I do call both HAL_FLASH_Unlock and HAL_FLASH_OB_Unlock before this operation.

[TDK]

Perhaps show the code you are using or follow the CubeG0 examples.

[LScha.3]

   HAL_FLASHEx_OBGetConfig(&pOBInit);

   pOBInit.OptionType = OPTIONBYTE_USER;

   flashConfig = pOBInit.USERConfig;

   flashConfig &= ~FLASH_OPTR_nBOOT1;

   flashConfig &= ~FLASH_OPTR_nBOOT_SEL;

   pOBInit.USERConfig = flashConfig;

   pOBInit.USERType = flashConfig;

   while(flashRet != HAL_OK){

      flashRet = HAL_FLASH_Unlock();

   }

   flashRet = HAL_TIMEOUT;

   flashRet = HAL_TIMEOUT;

   while(flashRet != HAL_OK){

      flashRet = HAL_FLASH_OB_Unlock();

   }

   flashRet = HAL_TIMEOUT;

   flashRet = HAL_FLASHEx_OBProgram(&pOBInit);

   HAL_FLASH_OB_Launch();

   flashRet = HAL_TIMEOUT;

   while(flashRet != HAL_OK){

      flashRet = HAL_FLASH_OB_Lock();

   }

   flashRet = HAL_TIMEOUT;

   while(flashRet != HAL_OK){

      flashRet = HAL_FLASH_Lock();

   }

[TDK]

>  pOBInit.USERConfig = flashConfig;

>  pOBInit.USERType = flashConfig;

Why are these set the same value? 

I'd recommend looking at the HAL source file for the correct parameters to pass here.

https://github.com/STMicroelectronics/STM32CubeWL/blob/de65a6e5e3aa178705e20c71f7d78db198a80ccc/Drivers/STM32WLxx_HAL_Driver/Inc/stm32wlxx_hal_flash.h#L73

The loops to lock/unlock are weird, and the first one uses an uninitialized flashRet, at least it's not initialized anywhere in the code you've presented. If locking fails once, the correct thing to do would be to find out why it failed, not blindly try again until it works.

You don't store the result from HAL_FLASH_OB_Launch, which would be the useful one to keep track of. Note that the chip resets after a successful call to this.

[LScha.3]

The previous code was an unsuccessful attempt to go around the problem.

The last try is this, still not working.

   FLASH_OBProgramInitTypeDef pOBInit;

   uint32_t flashConfig=0, usertype=0;

   HAL_StatusTypeDef flashRet = HAL_TIMEOUT;

   SET_BIT(RCC->AHBENR, RCC_AHBENR_FLASHEN);

   SET_BIT(FLASH->SR, FLASH_SR_PGAERR);

   SET_BIT(FLASH->SR, FLASH_SR_PGSERR);

   HAL_FLASHEx_OBGetConfig(&pOBInit);

   /* Unlock the Flash to enable the flash control register access */

   pOBInit.OptionType = OPTIONBYTE_USER;

   flashConfig = pOBInit.USERConfig;

   usertype = pOBInit.USERType;

   flashConfig &= ~FLASH_OPTR_nBOOT1;

   flashConfig &= ~FLASH_OPTR_nBOOT_SEL;

   usertype |= OB_USER_nBOOT1;

   usertype |= OB_USER_nBOOT_SEL;

   pOBInit.USERConfig = flashConfig;

   pOBInit.USERType = usertype;

   if(HAL_FLASH_Unlock() == HAL_OK){

      if(HAL_FLASH_OB_Unlock() == HAL_OK){

         HAL_FLASHEx_OBProgram(&pOBInit);

         HAL_FLASH_OB_Lock();

         HAL_FLASH_Lock();

      }

   }

I'm checking the OB_USER_nBOOT1 and FLASH_OPTR_nBOOT_SEL bits through STM32CUBE PROGRAMER