导语“我们在前面章节中使用了SDIO接口对SD卡进行读写操作，使用的轮询模式，这种模式效率低下，F103有SDIO接口的DMA模式，DMA模式在不需要CPU操作的情况下，自动的将数据进行读取和写入。”

(资料图片仅供参考)

第一节 系统要求

同第八章。

第二节 CubeMx配置

SDIO配置为4位的总线模式。

在DMA的配置中，SDIO的DMA通道只有一个，所以读和写之间需要进行方向改变。地址增长选择内存，这是因为我们把SDIO外设的数据发送到内存中，或从内存中读入数据。

在NVIC中断配置中，设置SDIO的中断优先级比DMA的优先级高。

玩成上述配置后，进行代码生成。

第三节 MDK代码编写

在stm32F103 中SDIO的DMA只有一个通道，因此读写是公用的，需要在读写之前进行方向配置，不能简单的调用HALSDReadBlocksDMA()库函数来完成读，不能简单的调用HALSDWriteBlocksDMA()来完成写操作。我们编写DIOReadBlocksDMA()、SDIOWriteBlocksDMA()来使用DMA模式。

（1）sdio.h

/* USER CODE BEGIN Private defines */extern DMA_HandleTypeDef hdma_sdio;/* USER CODE END Private defines *//* USER CODE BEGIN Prototypes */ HAL_StatusTypeDef SDIO_ReadBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks); HAL_StatusTypeDef SDIO_WriteBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks); /* USER CODE END Prototypes */在sdio.c中/* USER CODE BEGIN 1 */ HAL_StatusTypeDef SDIO_ReadBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks) {        HAL_StatusTypeDef Return_Status;        HAL_SD_CardStateTypeDef SD_Card_Status;        do        {               SD_Card_Status = HAL_SD_GetCardState(hsd);        }while(SD_Card_Status != HAL_SD_CARD_TRANSFER );        /* SDIO DMA DeInit */        /* SDIO DeInit */        HAL_DMA_DeInit(&hdma_sdio);        /* 改变DMA的方向，重新初始化 */        hdma_sdio.Instance = DMA2_Channel4;        hdma_sdio.Init.Direction = DMA_PERIPH_TO_MEMORY;        hdma_sdio.Init.PeriphInc = DMA_PINC_DISABLE;        hdma_sdio.Init.MemInc = DMA_MINC_ENABLE;        hdma_sdio.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;        hdma_sdio.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;        hdma_sdio.Init.Mode = DMA_NORMAL;        hdma_sdio.Init.Priority = DMA_PRIORITY_LOW;        if (HAL_DMA_Init(&hdma_sdio) != HAL_OK)        {               Error_Handler();        }        __HAL_LINKDMA( hsd,hdmarx,hdma_sdio);        Return_Status = HAL_SD_ReadBlocks_DMA( hsd,pData, BlockAdd, NumberOfBlocks);        return Return_Status; } HAL_StatusTypeDef SDIO_WriteBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks) {        HAL_StatusTypeDef Return_Status;        HAL_SD_CardStateTypeDef SD_Card_Status;        do        {               SD_Card_Status = HAL_SD_GetCardState(hsd);        }while(SD_Card_Status != HAL_SD_CARD_TRANSFER );        /* SDIO DMA DeInit */        /* SDIO DeInit */        HAL_DMA_DeInit(&hdma_sdio);        /* 改变DMA的方向，重新初始化 */        hdma_sdio.Instance = DMA2_Channel4;        hdma_sdio.Init.Direction = DMA_MEMORY_TO_PERIPH;        hdma_sdio.Init.PeriphInc = DMA_PINC_DISABLE;        hdma_sdio.Init.MemInc = DMA_MINC_ENABLE;        hdma_sdio.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;        hdma_sdio.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;        hdma_sdio.Init.Mode = DMA_NORMAL;        hdma_sdio.Init.Priority = DMA_PRIORITY_LOW;        if (HAL_DMA_Init(&hdma_sdio) != HAL_OK)        {               Error_Handler();        }        __HAL_LINKDMA(hsd,hdmatx,hdma_sdio);              Return_Status = HAL_SD_WriteBlocks_DMA(hsd,pData, BlockAdd, NumberOfBlocks);        return Return_Status; }

在min.c中

/*SD 操作*/typedef enum {FAILED= 0, PASSED = !FAILED} TestStatus;/* 私有宏定义 ----------------------------------------------------------------*/#define BLOCK_SIZE            512         // SD卡块大小     #define NUMBER_OF_BLOCKS      8           // 测试块数量(小于15)#define WRITE_READ_ADDRESS    0x00002000  // 测试读写地址#define SDMMC                            hsd/* 私有变量 ------------------------------------------------------------------*/__align(4) uint32_t Buffer_Block_Tx[BLOCK_SIZE*NUMBER_OF_BLOCKS]; // 写数据缓存__align(4) uint32_t Buffer_Block_Rx[BLOCK_SIZE*NUMBER_OF_BLOCKS]; // 读数据缓存HAL_StatusTypeDef sd_status;    // HAL库函数操作SD卡函数返回值：操作结果TestStatus test_status;           // 数据测试结果void        SD_EraseTest_DMA();void  SD_Write_Read_Test_DMA();HAL_StatusTypeDef Return_Status;HAL_SD_CardStateTypeDef SD_Card_Status;HAL_DMA_StateTypeDef DMA_Status;

在mian函数中：

//申明测试函数        SD_EraseTest_DMA();        SD_Write_Read_Test_DMA();

在main.c

/*************************************/TestStatus eBuffercmp(uint32_t* pBuffer, uint32_t BufferLength){  while (BufferLength--)  {    /* SD卡擦除后的可能值为0xff或0 */    if ((*pBuffer != 0xFFFFFFFF) && (*pBuffer != 0))    {      return FAILED;    }    pBuffer++;  }  return PASSED;}void SD_EraseTest_DMA(void){       /* 第1个参数为SD卡句柄，第2个参数为擦除起始地址，第3个参数为擦除结束地址 */  sd_status=HAL_SD_Erase(&SDMMC,WRITE_READ_ADDRESS,WRITE_READ_ADDRESS+NUMBER_OF_BLOCKS*4);   printf("《SD》""erase status:%drn",sd_status);       HAL_Delay(500);  if (sd_status == HAL_OK)  {           /* 读取刚刚擦除的区域 */    sd_status = SDIO_ReadBlocks_DMA(&SDMMC,(uint8_t *)Buffer_Block_Rx,WRITE_READ_ADDRESS,NUMBER_OF_BLOCKS);    printf("《SD》""erase read status:%drn",sd_status);    /* 把擦除区域读出来对比 */    test_status = eBuffercmp(Buffer_Block_Rx,BLOCK_SIZE*NUMBER_OF_BLOCKS);    if(test_status == PASSED)      printf("《SD》""除测试成功！rn" );     else               printf("《SD》""擦除不成功，数据出错！rn" );        }  else  {    printf("《SD》""擦除测试失败！部分SD不支持擦除，只要读写测试通过即可rn" );  }}void Fill_Buffer(uint32_t *pBuffer, uint32_t BufferLength, uint32_t Offset){  uint32_t index = 0;  /* 填充数据 */  for (index = 0; index < BufferLength; index++ )  {    pBuffer[index] = index + Offset;  }}TestStatus Buffercmp(uint32_t* pBuffer1, uint32_t* pBuffer2, uint32_t BufferLength){  while (BufferLength--)  {    if(BufferLength%50==0)    {      printf("buf:0x%08X - 0x%08Xrn",*pBuffer1,*pBuffer2);    }    if (*pBuffer1 != *pBuffer2)    {      return FAILED;    }    pBuffer1++;    pBuffer2++;  }  return PASSED;}void SD_Write_Read_Test_DMA(void){         printf(" Warning: this programmay erase all the TFcard data. rn");       printf("rn Initialize SD card successfully!rnrn");       printf(" SD card information! rn");       printf(" CardCapacity  : %llu rn",((unsigned long long)SDMMC.SdCard.BlockSize*hsd.SdCard.BlockNbr));       printf(" CardBlockSize : %d rn",SDMMC.SdCard.BlockSize);       printf(" RCA           : %d rn",SDMMC.SdCard.RelCardAdd);       printf(" CardType      : %d rn",SDMMC.SdCard.CardType);       int i,j = 0;  /* 填充数据到写缓存 */  Fill_Buffer(Buffer_Block_Tx,BLOCK_SIZE*NUMBER_OF_BLOCKS, 0x6666);  /* 往SD卡写入数据 */  sd_status = SDIO_WriteBlocks_DMA(&SDMMC,(uint8_t *)Buffer_Block_Tx,WRITE_READ_ADDRESS,NUMBER_OF_BLOCKS);  printf("《SD》""write status:%drn",sd_status);  HAL_Delay(600);  /* 从SD卡读取数据 */  sd_status = SDIO_ReadBlocks_DMA(&SDMMC,(uint8_t *)Buffer_Block_Rx,WRITE_READ_ADDRESS,NUMBER_OF_BLOCKS);  printf("《SD》""read status:%drn",sd_status);  /* 比较数据 */  test_status = Buffercmp(Buffer_Block_Tx, Buffer_Block_Rx, BLOCK_SIZE*NUMBER_OF_BLOCKS/4);       //比较  if(test_status == PASSED)       {    printf("《SD》""》读写测试成功！rn" );              for(i=0;i

第四节 效果演示

可以看到能够正确的使用DMA进行SD卡的读写操作。

第五节 补充DMA 补充

我们在上一节中使用DMA的使用读写过程中要改变DMA的方向，在每个读写函数中进行，可以单独实现：

在sdio.h

HAL_StatusTypeDef SD_DMAConfigRX(SD_HandleTypeDef *hsd);HAL_StatusTypeDef SD_DMAConfigTX(SD_HandleTypeDef *hsd);HAL_StatusTypeDef SDIO_ReadBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks);HAL_StatusTypeDef SDIO_WriteBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks);

在sdio.c 中

HAL_StatusTypeDef SDIO_ReadBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks){       HAL_StatusTypeDef Return_Status;       HAL_SD_CardStateTypeDef SD_Card_Status;       do       {              SD_Card_Status = HAL_SD_GetCardState(hsd);       }while(SD_Card_Status != HAL_SD_CARD_TRANSFER );       if (SD_DMAConfigRX(hsd) != HAL_OK)       {              return HAL_ERROR;       }       else       {              Return_Status = HAL_SD_ReadBlocks_DMA( hsd,pData, BlockAdd, NumberOfBlocks);              return Return_Status;       }}HAL_StatusTypeDef SDIO_WriteBlocks_DMA(SD_HandleTypeDef *hsd, uint8_t *pData, uint32_t BlockAdd, uint32_t NumberOfBlocks){       HAL_StatusTypeDef Return_Status;       HAL_SD_CardStateTypeDef SD_Card_Status;       do       {              SD_Card_Status = HAL_SD_GetCardState(hsd);       }while(SD_Card_Status != HAL_SD_CARD_TRANSFER );       if (SD_DMAConfigTX(hsd) != HAL_OK)       {              return HAL_ERROR;       }       else       {              Return_Status = HAL_SD_WriteBlocks_DMA(hsd,pData, BlockAdd, NumberOfBlocks);              return Return_Status;       }}HAL_StatusTypeDef SD_DMAConfigRX(SD_HandleTypeDef *hsd){       HAL_StatusTypeDef status = HAL_ERROR;       hdma_sdio.Instance = DMA2_Channel4;       hdma_sdio.Init.Direction = DMA_PERIPH_TO_MEMORY;       hdma_sdio.Init.PeriphInc = DMA_PINC_DISABLE;       hdma_sdio.Init.MemInc = DMA_MINC_ENABLE;       hdma_sdio.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;       hdma_sdio.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;       hdma_sdio.Init.Mode = DMA_NORMAL;       hdma_sdio.Init.Priority = DMA_PRIORITY_LOW;       __HAL_LINKDMA( hsd,hdmarx,hdma_sdio);       HAL_DMA_Abort(&hdma_sdio);       HAL_DMA_DeInit(&hdma_sdio);       status = HAL_DMA_Init(&hdma_sdio);       return status;}HAL_StatusTypeDef SD_DMAConfigTX(SD_HandleTypeDef *hsd){       HAL_StatusTypeDef status = HAL_ERROR;       hdma_sdio.Instance = DMA2_Channel4;       hdma_sdio.Init.Direction = DMA_MEMORY_TO_PERIPH;       hdma_sdio.Init.PeriphInc = DMA_PINC_DISABLE;       hdma_sdio.Init.MemInc = DMA_MINC_ENABLE;       hdma_sdio.Init.PeriphDataAlignment = DMA_PDATAALIGN_WORD;       hdma_sdio.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;       hdma_sdio.Init.Mode = DMA_NORMAL;       hdma_sdio.Init.Priority = DMA_PRIORITY_LOW;       __HAL_LINKDMA( hsd,hdmarx,hdma_sdio);       HAL_DMA_Abort(&hdma_sdio);       HAL_DMA_DeInit(&hdma_sdio);       status = HAL_DMA_Init(&hdma_sdio);       return status;}