stm32c011 in-application option byte programming

[AndreasS]

Good morning,

I'm trying to program the user option bytes of the STM32C011 using the HAL. The objective of the test is to toggle the BOR bit.

static HAL_StatusTypeDef testOptionBytes()
{
    FLASH_OBProgramInitTypeDef obInit = {0};
    FLASH_OBProgramInitTypeDef obProgram = {0};
    FLASH_OBProgramInitTypeDef obCmp = {0};
    HAL_StatusTypeDef status = HAL_OK;

    HAL_FLASHEx_OBGetConfig(&obInit);

    status = HAL_FLASH_Unlock();
    assert(status == HAL_OK);
    status = HAL_FLASH_OB_Unlock();
    assert(status == HAL_OK);

    obProgram.OptionType = OPTIONBYTE_USER;
    obProgram.USERType = OB_USER_BOR_EN;
    obProgram.USERConfig = (obInit.USERConfig & OB_USER_BOR_EN) ^ OB_USER_BOR_EN;
    status = HAL_FLASHEx_OBProgram(&obProgram);
    assert(status == HAL_OK);

    HAL_FLASH_OB_Lock();
    HAL_FLASH_Lock();

    HAL_FLASHEx_OBGetConfig(&obCmp);
    assert(obInit.USERConfig != obCmp.USERConfig);

    return status;
}

When I step through the HAL code everything looks fine, the FLASH->OPTR register is written with the correct value, but the final assert() always fails.

Have I overseen something here?

Thanks in advance, Andreas

[SofLit · Accepted solution]

You need to call HAL_FLASH_OB_Launch()  after HAL_FLASHEx_OBProgram()