既然要实现两个盘，当然在usb_prop.c中的Max_Lun变量赋值为1，在USB_User组中同时添加fsmc_nand.c和sdio_sdcard.c这两个文件，在外设库中挺尸添加stm32f10x_sdio.c和stm32f10x_fsmc.c两个文件。

添加完之后，可能会有些许的错误，解决完后，我们就要修改下mass_mal.c文件了，这个文件本次要同时实现SD卡和NAND Flash的相关驱动代码的挂接，代码如下：

uint32_t Mass_Memory_Size[2];
uint32_t Mass_Block_Size[2];
uint32_t Mass_Block_Count[2];
__IO uint32_t Status = 0;

uint16_t MAL_Init(uint8_t lun)
{    u16 status = MAL_OK;   switch (lun)
    {        case 0:
            Status = SD_Init();  //调用SD初始化函数
            break;
        case 1:
            FlashInit();
            break;
        default:
            return MAL_FAIL;
  }
  return status;
}

uint16_t MAL_Write(uint8_t lun, uint32_t Memory_Offset, uint32_t *Writebuff, uint16_t Transfer_Length)
{    switch (lun)
    {        case 0:
            Status = SD_WriteBlock((uint8_t*)Writebuff, Memory_Offset, Transfer_Length);
            SD_WaitWriteOperation();                    //等待dma传输结束
            while(SD_GetStatus() != SD_TRANSFER_OK);   //等待sdio到sd卡传输结束
            if ( Status != SD_OK )
            {                return MAL_FAIL;
            }
            break;
        case 1:
            FlashWriteOneSector(Memory_Offset,(u8*)Writebuff, Transfer_Length);
                break;
    default:
      return MAL_FAIL;
  }
  return MAL_OK;
}

uint16_t MAL_Read(uint8_t lun, uint32_t Memory_Offset, uint32_t *Readbuff, uint16_t Transfer_Length)
{  switch (lun)
  {    case 0:
        Status = SD_ReadBlock((uint8_t*)Readbuff, Memory_Offset, Transfer_Length);
        SD_WaitReadOperation();                 //等待dma传输结束
        while(SD_GetStatus() != SD_TRANSFER_OK);   //等待sdio到sd卡传输结束
        if ( Status != SD_OK )
        {            return MAL_FAIL;
        }
        break;
    case 1:
        FlashReadOneSector(Memory_Offset, (u8*)Readbuff, Transfer_Length);
        break;
    default:
      return MAL_FAIL;
  }
  return MAL_OK;
}

uint16_t MAL_GetStatus (uint8_t lun)
{    uint32_t DeviceSizeMul = 0, NumberOfBlocks = 0;
    if (lun == 0)
    {        if (SD_Init() == SD_OK)
        {            SD_GetCardInfo(&SDCardInfo);
            SD_SelectDeselect((uint32_t) (SDCardInfo.RCA << 16));
            DeviceSizeMul = (SDCardInfo.SD_csd.DeviceSizeMul + 2);

            if(SDCardInfo.CardType == SDIO_HIGH_CAPACITY_SD_CARD)
            {                Mass_Block_Count[0] = (SDCardInfo.SD_csd.DeviceSize + 1) * 1024;
            }
            else
            {                NumberOfBlocks  = ((1 << (SDCardInfo.SD_csd.RdBlockLen)) / 512);
                Mass_Block_Count[0] = ((SDCardInfo.SD_csd.DeviceSize + 1) * (1 << DeviceSizeMul) << (NumberOfBlocks/2));
            }
            Mass_Block_Size[0]  = 512;

            Status = SD_SelectDeselect((uint32_t) (SDCardInfo.RCA << 16));
            Status = SD_EnableWideBusOperation(SDIO_BusWide_4b);
            if ( Status != SD_OK )
            {                return MAL_FAIL;
            }
            LED2_ON();
            return MAL_OK;
        }
        else
        {            LED2_OFF();
        }
    }
    else
    {        Mass_Block_Count[1] =  FLASH_MAX_SECTOR_ADDR/FLASH_SECTOR_SIZE;  //NAND_ZONE_SIZE * NAND_BLOCK_SIZE * NAND_MAX_ZONE ;
        Mass_Block_Size[1]  =  FLASH_SECTOR_SIZE;                        //NAND_PAGE_SIZE;
        Mass_Memory_Size[1] = (Mass_Block_Count[1] * Mass_Block_Size[1]);//这里的NAND要选择Mass_Block_Count[1]和Mass_Block_Size[1]
        LED4_ON();                                                       //因为SD的的是Mass_Block_Count[0]和Mass_Block_Size[0]
        return MAL_OK;
    }
    return MAL_FAIL;
}

这样就可以在电脑上同时出现两个盘，分别是SD卡和NAND模拟出来的。

在调是这个代码之前，曾经粗心，把MAL_GetStatus()l里的NAND相关代码的下成如下：

Mass_Block_Count[0] = FLASH_MAX_SECTOR_ADDR/FLASH_SECTOR_SIZE;
Mass_Block_Size[0] = FLASH_SECTOR_SIZE;
Mass_Memory_Size[0] = (Mass_Block_Count[0] * Mass_Block_Size[0]);

数组元素都是0，与SD卡冲突，导致两个盘都显示不出来，但是你屏蔽掉SD相关的代码是可以的，或则屏蔽掉NAND相关代码也是可以的，偏偏两个代码一起的时候不行，检查了半天，才发现问题出在这里。