STM32L4 SDMMC + FATFS

[lorant124]

Hi,

I would like using SD card with FATFS and read/write to SD card.

If i have bare-metal FW without DMA template enable it is work.

But if I enable DMA template f_mount, f_open return FR_OK but f_write, f_read Disc_error.

I setted in CubeMX SDMMC1- SD 1bit.

In DMA window added shared DMA channel (RX/TX SDMMC)

In Fatfs enabled dma template.

But doesnt work.

If in FatFS disable dma template, read/write is work propertly.

I using STM32L496RG

CubeMX 6.1.1

FW package 1.16.0

Please help.

thank you

[lorant124 · Accepted solution]

I have found the solution to this problem:

2 way (RX,TX) dma doesnt work, I dont known why...

But shared DMA channel yes but in BSP_driver_cd.c CubeMX doesnt generate propertly Write *** Read function.

in file bsp_driver_sd.c in function modify BSP_SD_WriteBlocks_DMA(...):

__weak uint8_t BSP_SD_WriteBlocks_DMA(uint32_t *pData, uint32_t WriteAddr, uint32_t NumOfBlocks)
{
  uint8_t sd_state = MSD_OK;
 
  // Since we are only using 1 DMA channel for SDMMC
  // Change DMA direction before calling SD Read
  // Direction can only be changed when DMA is disabled
 
  __HAL_DMA_DISABLE(hsd1.hdmatx);
  hsd1.hdmatx->Init.Direction = DMA_MEMORY_TO_PERIPH;
  hsd1.hdmatx->Instance->CCR |= (uint32_t)DMA_CCR_DIR;
 
  /* Write block(s) in DMA transfer mode */
  if (HAL_SD_WriteBlocks_DMA(&hsd1, (uint8_t *)pData, WriteAddr, NumOfBlocks) != HAL_OK)
  {
    sd_state = MSD_ERROR;
  }
 
  return sd_state;
}

in file bsp_driver_sd.c in function modify BSP_SD_ReadBlocks_DMA(...):

__weak uint8_t BSP_SD_ReadBlocks_DMA(uint32_t *pData, uint32_t ReadAddr, uint32_t NumOfBlocks)
{
  uint8_t sd_state = MSD_OK;
  // Since we are only using 1 DMA channel for SDMMC
  // Change DMA direction before calling SD Read
  // Direction can only be changed when DMA is disabled
 
  __HAL_DMA_DISABLE(hsd1.hdmarx);
  hsd1.hdmarx->Init.Direction = DMA_PERIPH_TO_MEMORY;
  hsd1.hdmarx->Instance->CCR &= ~DMA_CCR_DIR;
 
  /* Read block(s) in DMA transfer mode */
  if (HAL_SD_ReadBlocks_DMA(&hsd1, (uint8_t *)pData, ReadAddr, NumOfBlocks) != HAL_OK)
  {
    sd_state = MSD_ERROR;
  }
 
  return sd_state;
}

Solution first posted superspud9 on reddit.

thanks

[antfarmer]

This is great info. I don't know how we are supposed to find this out.

Anyway, FWIW, since the functions in bsp_driver_sd.c are defined as weak, you can define them anywhere in your code that is called and it will override the implementations in bsp_driver_sd.c. That way you can avoid having to replace the code each time it is auto-generated.