SWM32系列教程9-SDIO及FatFs文件系统_swm32s

SWM32S单片机有1个SDIO接口，支持多媒体卡（MMC）、SD 存储卡、SDIO 卡等设备，可以使用软件方法或者 DMA 方法（SDIO 模块内部 DMA，与芯片 DMA 模块无关）进行数据传输。其特点如下：

 

 

1.SDIO配置

    SDIO的引脚不像UART和SPI等数字外设一样可以灵活配置，它是固定的几个引脚，如下图

    使用起来也比较简单，相关的库函数已经封装好了，直接调用就行。

    首先需要配置一下相关引脚的复用功能为SDIO：            

  PORT_Init(PORTB, PIN1, PORTB_PIN1_SD_CLK, 0);
  PORT_Init(PORTB, PIN2, PORTB_PIN2_SD_CMD, 1);
  PORT_Init(PORTB, PIN3, PORTB_PIN3_SD_D0,  1);
  PORT_Init(PORTB, PIN4, PORTB_PIN4_SD_D1,  1);
  PORT_Init(PORTB, PIN5, PORTB_PIN5_SD_D2,  1);
  PORT_Init(PORTB, PIN6, PORTB_PIN6_SD_D3,  1);

    然后直接调用初始化的函数就行：    

result = SDIO_Init(10000000);

    其中形参为SDIO的时钟频率。

    SD卡读写的相关函数也已经封装好了，包括DMA和非DMA方式，直接调用即可：

uint32_t SDIO_BlockWrite(uint32_t block_addr, uint32_t buff[]);
uint32_t SDIO_BlockRead(uint32_t block_addr, uint32_t buff[]);
uint32_t SDIO_MultiBlockWrite(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);
uint32_t SDIO_MultiBlockRead(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);
uint32_t SDIO_DMABlockWrite(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);
uint32_t SDIO_DMABlockRead(uint32_t block_addr, uint16_t block_cnt, uint32_t buff[]);

2.FatFs移植

    底层读写函数有了以后，移植FatFs也就比较简单了，首先将FatFs的相关文件添加到工程中：

    我们需要实现的接口函数在diskio.c文件中，包括至少以下3个函数：

    初始化函数，直接将端口配置、SDIO初始化添加到该函数中：

 

DSTATUS disk_initialize (
  BYTE pdrv        /* Physical drive nmuber to identify the drive */
)
{
  DSTATUS stat;
  int result;
 
  switch (pdrv) {
  case DEV_RAM :
    //result = RAM_disk_initialize();
    // translate the reslut code here
    stat = STA_NOINIT;
    return stat;
  case DEV_MMC :
    //result = MMC_disk_initialize();
    // translate the reslut code here
    PORT_Init(PORTB, PIN1, PORTB_PIN1_SD_CLK, 0);
    PORT_Init(PORTB, PIN2, PORTB_PIN2_SD_CMD, 1);
    PORT_Init(PORTB, PIN3, PORTB_PIN3_SD_D0,  1);
    PORT_Init(PORTB, PIN4, PORTB_PIN4_SD_D1,  1);
    PORT_Init(PORTB, PIN5, PORTB_PIN5_SD_D2,  1);
    PORT_Init(PORTB, PIN6, PORTB_PIN6_SD_D3,  1);  
    result = SDIO_Init(10000000);
    if(result == SD_RES_OK)
    {
      stat = RES_OK;
      sd_initialized = 1;
    }
    else
    {
      stat = STA_NOINIT;
      sd_initialized = 0;
    }
    return stat;
  case DEV_USB :
    //result = USB_disk_initialize();
    // translate the reslut code here
    stat = STA_NOINIT;
    return stat;
  }
  return STA_NOINIT;
}

    读函数：

DRESULT disk_read (
  BYTE pdrv,    /* Physical drive nmuber to identify the drive */
  BYTE *buff,    /* Data buffer to store read data */
  LBA_t sector,  /* Start sector in LBA */
  UINT count    /* Number of sectors to read */
)
{
  DRESULT res;
  int result;
 
  switch (pdrv) {
  case DEV_RAM :
    // translate the arguments here
    //result = RAM_disk_read(buff, sector, count);
    // translate the reslut code here
    res = RES_PARERR;
    return res;
  case DEV_MMC :
 
    if(count == 1)
    {
      result = SDIO_BlockRead(sector, (uint32_t *)buff);
    }
    else
    {
      //result = SDIO_MultiBlockRead(sector, count, (uint32_t *)buff);
        result = SDIO_DMABlockRead(sector, count, (uint32_t *)buff);//使用DMA或非DMA模式均可
    }  
    if(result == SD_RES_OK)
      res = RES_OK;
    else
      res = RES_ERROR;    
    return res;
  case DEV_USB :
    // translate the arguments here
    //result = USB_disk_read(buff, sector, count);
    // translate the reslut code here  
    res = RES_PARERR;
    return res;
  }
  return RES_PARERR;
}

    写函数：

DRESULT disk_write (
  BYTE pdrv,      /* Physical drive nmuber to identify the drive */
  const BYTE *buff,  /* Data to be written */
  LBA_t sector,    /* Start sector in LBA */
  UINT count      /* Number of sectors to write */
)
{
  DRESULT res;
  int result;
 
  switch (pdrv) {
  case DEV_RAM :
    // translate the arguments here
    //result = RAM_disk_write(buff, sector, count);
    // translate the reslut code here
    res = RES_PARERR;
    return res;
  case DEV_MMC :
    if(count == 1)
    {
      result = SDIO_BlockWrite(sector, (uint32_t *)buff);
    }
    else
    {
      //result = SDIO_MultiBlockWrite(sector, count, (uint32_t *)buff);
      result = SDIO_DMABlockWrite(sector, count, (uint32_t *)buff);//使用DMA或非DMA模式均可
    }
    if(result == SD_RES_OK)
      res = RES_OK;
    else
      res = RES_ERROR;
    return res;
  case DEV_USB :
    // translate the arguments here
    //result = USB_disk_write(buff, sector, count);
    // translate the reslut code here
    res = RES_PARERR;
    return res;
  }
  return RES_PARERR;
}

  还有一个函数是用户获取SD卡容量等信息的，如下：

DRESULT disk_ioctl (
  BYTE pdrv,    /* Physical drive nmuber (0..) */
  BYTE cmd,    /* Control code */
  void *buff    /* Buffer to send/receive control data */
)
{
  DRESULT res;
  //int result;
 
  switch (pdrv) {
  case DEV_RAM :
    // Process of the command for the RAM drive
    res = RES_PARERR;
    return res;
  case DEV_MMC :
    switch ( cmd ) 
    {      //fatfs内核使用cmd调用
      case GET_SECTOR_COUNT:  //sector count
          *(DWORD*)buff = SD_cardInfo.CardCapacity / 512;
          return RES_OK;
      case GET_SECTOR_SIZE:  //sector size, 传入block size(SD),单位bytes
          *(DWORD*)buff = 512;
          return RES_OK;
      case GET_BLOCK_SIZE:  //block size, 由上文可得，对于SD2.0卡最大8192，最小 1
          *(DWORD*)buff = 1;  //单位为 sector(FatFs)
          return RES_OK;
      case CTRL_SYNC:      //同步命令，貌似FatFs内核用来判断写操作是否完成
          return RES_OK;
    }
    res = RES_OK;
    return res;
  case DEV_USB :
    // Process of the command the USB drive
    res = RES_PARERR;
    return res;
  }
  return RES_PARERR;
}

   接口部分实现后，就可以调用相关的函数实现文件的读写了，测试程序如下：

res = f_mount(&fatfs, "sd:", 1);
if(res != FR_OK)
{
  printf("sdcard init fail!\r\n");
}
res = f_open(&filw, "sd:test.txt", FA_CREATE_ALWAYS | FA_WRITE);
if(res != FR_OK)
{
  printf("create file fail!\r\n");
}
res = f_write(&filw, str, strlen(str), &len);
if(res != FR_OK)
{
  printf("write file fail!\r\n");
}
f_close(&filw);

    文件系统的配置可以在"ffconf.h"文件中根据实际需求进行修改。