This is my first time to use the MPU of STM so how can I find the example codes about STM32L476VG development board?

[Olivier GALLIEN]

Hi @ZMa.1​ 

STM32L4 is an MCU not an MPU.

I have change the topic accordingly.

To find example code matching your board refer to STM32CubeProjectsList.html file present in STM32L4 firmware package. ( https://www.st.com/en/embedded-software/stm32cubel4.html )

Hope it help

Olivier

[waclawek.jan]

@Community member​ ,

@ZMa.1​ might be talking about the Memory Protection Unit in the Cortex-M4 core of STM32L4.

@ZMa.1​ ,

The MPU in the Cortex-M3/M4-based mcus is rarely used, so I don't think you'll find many examples. As it's not STM32-specific, you may want to look around and try finding examples also at other Cortex-M3/M4 chips, and/or have a look at Joseph Yiu's "The definitive guide to..." books.

JW

[Tesla DeLorean]

Better examples of MPU configuration can be found in F7 and H7 where real cache coherency issues can arise.

Use grep or file manager of choice to search.

/**
  * @brief  Configure the MPU attributes as Write Through for External SDRAM.
  * @note   The Base Address is SDRAM_DEVICE_ADDR .
  *         The Configured Region Size is 32MB because same as SDRAM size.
  * @param  None
  * @retval None
  */
static void MPU_Config(void)
{
  MPU_Region_InitTypeDef MPU_InitStruct;
 
  /* Disable the MPU */
  HAL_MPU_Disable();
 
  /* Configure the MPU attributes as WT for SDRAM */
  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
  MPU_InitStruct.BaseAddress = SDRAM_DEVICE_ADDR;
  MPU_InitStruct.Size = MPU_REGION_SIZE_32MB;
  MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
  MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
  MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE;
  MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
  MPU_InitStruct.Number = MPU_REGION_NUMBER0;
  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
  MPU_InitStruct.SubRegionDisable = 0x00;
  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
 
  HAL_MPU_ConfigRegion(&MPU_InitStruct);
 
  /* Enable the MPU */
  HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
} 

Same MPU stuff in L4

STM32Cube_FW_L4_V1.14.0\Drivers\STM32L4xx_HAL_Driver\Src\stm32l4xx_hal_cortex.c