導語"fatfs是一個小型的文件系統，在小型的嵌入式系統中使用非常的廣泛，STM32CubeMx自帶該文件系統，我們通過簡單的配置就能夠使用，將前面的SD卡的讀寫操作進行修改，將文件系統掛載到SD卡進行操作，通過簡單的文件創建、打開、寫入、讀取、關閉來演示如果使用Fatfs。"

第一節 系統要求

?軟件

STM32CubeMX

?硬件

野火指南者開發板，SD卡

第二節 CubeMX配置

本節使用SDIO接口與SD卡連接，利用DMA模式讀寫SD卡，將FATFS文件系統掛載SD卡中。

1.SDIO配置

1.DMA配置

2.中斷配置

3.Fatfs 文件系統的配置

Fatfs配置中我們選在支持中文文件名。選在SD Card,設置為logical drivers 為1.

按照上述配置后點擊代碼生成。

第三節 MDK 代碼編寫

使用MDK打開項目，在bspdriversd.c 中修改代碼,并包含頭文件#include "sdio.h"。

在BSPSDReadBlocks() 函數中修改，使用前面編寫好的SDIO DMA讀寫的函數進行SD卡的讀寫，Fatfs文件系統將會在SDRead() 和SDWrite()調用該函數。

/* USER CODE END BeforeReadBlocksSection */ 
/** 
  * @brief  Reads block(s) from a specified address in an SD card, in polling mode. 
  * @param  pData: Pointer to the buffer that will contain the data to transmit 
  * @param  ReadAddr: Address from where data is to be read 
  * @param  NumOfBlocks: Number of SD blocks to read 
  * @param  Timeout: Timeout for read operation 
  * @retval SD status 
  */ 
__weak uint8_t BSP_SD_ReadBlocks(uint32_t *pData, uint32_t ReadAddr, uint32_t NumOfBlocks, uint32_t Timeout) 
{ 
  uint8_t sd_state = MSD_OK; 


  if (SDIO_ReadBlocks_DMA(&hsd, (uint8_t*)pData,ReadAddr,NumOfBlocks) != HAL_OK) 
  { 
    sd_state = MSD_ERROR; 
  } 


  return sd_state; 
} 


/* USER CODE BEGIN BeforeWriteBlocksSection */ 
/* can be used to modify previous code / undefine following code / add code */ 
/* USER CODE END BeforeWriteBlocksSection */ 
/** 
  * @brief  Writes block(s) to a specified address in an SD card, in polling mode. 
  * @param  pData: Pointer to the buffer that will contain the data to transmit 
  * @param  WriteAddr: Address from where data is to be written 
  * @param  NumOfBlocks: Number of SD blocks to write 
  * @param  Timeout: Timeout for write operation 
  * @retval SD status 
  */ 
__weak uint8_t BSP_SD_WriteBlocks(uint32_t *pData, uint32_t WriteAddr, uint32_t NumOfBlocks, uint32_t Timeout) 
{ 
  uint8_t sd_state = MSD_OK; 


  if (SDIO_WriteBlocks_DMA(&hsd, (uint8_t*)pData,WriteAddr,NumOfBlocks) != HAL_OK) 
  { 
    sd_state = MSD_ERROR; 
  } 


  return sd_state; 
}

直接修改SD的讀寫函數，在內部使用DMA模式。也可以在sddiskio.c 中修改SDread 和SD_Write 但是發現這個文件是只讀模式，所以就不修改了。：

/**
  * @brief  Reads Sector(s)
  * @param  lun : not used
  * @param  *buff: Data buffer to store read data
  * @param  sector: Sector address (LBA)
  * @param  count: Number of sectors to read (1..128)
  * @retval DRESULT: Operation result
  */
DRESULT SD_read(BYTE lun, BYTE *buff, DWORD sector, UINT count)
{
  DRESULT res = RES_ERROR;
  uint32_t timeout = 100000;


  if(BSP_SD_ReadBlocks((uint32_t*)buff, 
                       (uint32_t) (sector), 
                       count, SD_DATATIMEOUT) == MSD_OK)
  {
    while(BSP_SD_GetCardState()!= MSD_OK)
    {
      if (timeout-- == 0)
      {
        return RES_ERROR;
      }
    }
    res = RES_OK;
  }

  return res;
}


/**
  * @brief  Writes Sector(s)
  * @param  lun : not used
  * @param  *buff: Data to be written
  * @param  sector: Sector address (LBA)
  * @param  count: Number of sectors to write (1..128)
  * @retval DRESULT: Operation result
  */
#if _USE_WRITE == 1
DRESULT SD_write(BYTE lun, const BYTE *buff, DWORD sector, UINT count)
{
  DRESULT res = RES_ERROR;
  uint32_t timeout = 100000;


  if(BSP_SD_WriteBlocks((uint32_t*)buff, 
                        (uint32_t)(sector), 
                        count, SD_DATATIMEOUT) == MSD_OK)
  {
    while(BSP_SD_GetCardState()!= MSD_OK)
    {
      if (timeout-- == 0)
      {
        return RES_ERROR;
      }
    }    
    res = RES_OK;
  }

  return res;
}
#endif /* _USE_WRITE == 1 */

編譯下載進行測試：

第四節效果演示

我們可以看見文件讀寫測試能夠正常使用。