Enable SRAM parity check

[DDU]

How can I enable the parity check in the SRAM 2 of the STM32L4?

Is there a HAL function?

[Tesla DeLorean]

You have to configure a bit in the Options Bytes, try looking at related examples for reading/writing those and extend to your requirements

STM32Cube_FW_L4_V1.12.0\Projects\STM32L476G-EVAL\Applications\IAP\IAP_Main\Src\flash_if.c

STM32Cube_FW_L4_V1.12.0\Projects\32L476GDISCOVERY\Examples\FLASH\FLASH_DualBoot\Src

STM32Cube_FW_L4_V1.12.0\Projects\32L476GDISCOVERY\Examples\FLASH\FLASH_WriteProtection\Src

STM32Cube_FW_L4_V1.12.0\Drivers\STM32L4xx_HAL_Driver\Src\stm32l4xx_hal_flash_ex.c

/**

 * @brief Program the FLASH User Option Byte.

 *

 * @note  To configure the user option bytes, the option lock bit OPTLOCK must

 *        be cleared with the call of the HAL_FLASH_OB_Unlock() function.

 * @note  To validate the user option bytes, the option bytes must be reloaded

 *        through the call of the HAL_FLASH_OB_Launch() function.

 *

 * @param UserType: The FLASH User Option Bytes to be modified

 * @param UserConfig: The FLASH User Option Bytes values:

 *        BOR_LEV(Bit8-10), nRST_STOP(Bit12), nRST_STDBY(Bit13), IWDG_SW(Bit16),

 *        IWDG_STOP(Bit17), IWDG_STDBY(Bit18), WWDG_SW(Bit19), BFB2(Bit20),

 *        DUALBANK(Bit21), nBOOT1(Bit23), SRAM2_PE(Bit24) and SRAM2_RST(Bit25).

 *

 * @retval HAL status

 */

static HAL_StatusTypeDef FLASH_OB_UserConfig(uint32_t UserType, uint32_t UserConfig)

{

..

   if((UserType & OB_USER_SRAM2_PE) != 0U)

   {

     /* SRAM2_PE option byte should be modified */

     assert_param(IS_OB_USER_SRAM2_PARITY(UserConfig & FLASH_OPTR_SRAM2_PE));

     /* Set value and mask for SRAM2_PE option byte */

     optr_reg_val |= (UserConfig & FLASH_OPTR_SRAM2_PE);

     optr_reg_mask |= FLASH_OPTR_SRAM2_PE;

   }

[DDU]

FLASH_OB_UserConfig() is a static function. I use HAL_FLASHEx_OBProgram() which calls FLASH_OB_UserConfig():

  HAL_FLASHEx_OBGetConfig(&optionBytesInit);

  optionBytesInit.USERType |= OB_USER_SRAM2_PE;

  optionBytesInit.USERConfig &= ~FLASH_OPTR_SRAM2_PE_Msk;

  HAL_FLASH_OB_Unlock();

  HAL_FLASHEx_OBProgram(&optionBytesInit);

  HAL_FLASH_OB_Lock();

  HAL_FLASH_OB_Launch();

But HAL_FLASH_OB_Unlock() generates a hard fault.

[waclawek.jan]

Do you have some of the lock or other options set through device programming?

JW

[DDU]

I don't set anything actively during programming, but we use IAR (V8.20) and HAL (V1.8.3).

The value of the option register (FLASH->OPTR) is 0xFFEFF8AA.

[DDU]

Do someone from ST could check if the SRAM2 parity enable bit can be reset to 0 (0 = parity check enabled!) in the STM32L4A6ZG?

The code in not working:

  FLASH_OBProgramInitTypeDef optionBytesInit = {0U};

  HAL_FLASHEx_OBGetConfig(&optionBytesInit);

  optionBytesInit.USERType |= OB_USER_SRAM2_PE;

  optionBytesInit.USERConfig &= ~FLASH_OPTR_SRAM2_PE;

  HAL_FLASH_OB_Unlock();

  HAL_FLASH_Unlock();

  HAL_FLASHEx_OBProgram(&optionBytesInit);

  if (HAL_FLASH_OB_Launch() != HAL_OK)

  {

    while(1);

  }

  HAL_FLASH_OB_Lock();

  HAL_FLASH_Lock();

The SRAM2_PE is always 1 (instead of 0).

And a bus fault arise afterwards.

[Tesla DeLorean]

>>Do someone from ST could check if the SRAM2 parity enable bit...

This is predominantly a user forum, you should work with the ST FAE supporting your account, or those at your distributor. Or file an Online Support request.