STM32F429 U盘读写Txt实现

1、打开USB_OTG_HS

2、使能USB_HOST

3、使能FATFS

4、生成基本工程模版

5、打开程序工程文件，添加测试代码：

①main.c中添加MSC_Application（）

/* USER CODE BEGIN 0 */
extern ApplicationTypeDef Appli_state;
extern USBH_HandleTypeDef hUsbHostFS;
extern char USBHPath[4]; // USBH logical drive path

FATFS FatfsUDisk; // File system object for USB disk logical drive
FIL MyFile; // File object
char USBDISKPath[4];          /* USB Host logical drive path */
USBH_HandleTypeDef hUSBHost; /* USB Host handle */
 
static void MSC_Application(void)
{
  FRESULT res;                                          /* FatFs function common result code */
  uint32_t byteswritten, bytesread;                     /* File write/read counts */
  uint8_t wtext[] = "This is STM32 working with FatFs"; /* File write buffer */
  uint8_t rtext[100];                                   /* File read buffer */
 
    /* Register the file system object to the FatFs module */
    if( f_mount(&FatfsUDisk, (TCHAR const*)USBHPath, 0) != FR_OK)
    {
        Error_Handler(); //FatFs Initialization Error
    }
    else
        {
      /* Create and Open a new text file object with write access */
      if(f_open(&MyFile, "STM32.TXT", FA_CREATE_ALWAYS | FA_WRITE) != FR_OK) 
      {
        /* 'STM32.TXT' file Open for write Error */
        Error_Handler();
      }
      else
      {
        /* Write data to the text file */
        res = f_write(&MyFile, wtext, sizeof(wtext), (void *)&byteswritten);
        
        if((byteswritten == 0) || (res != FR_OK))
        {
          /* 'STM32.TXT' file Write or EOF Error */
          Error_Handler();
        }
        else
        {
          /* Close the open text file */
          f_close(&MyFile);
          
        /* Open the text file object with read access */
        if(f_open(&MyFile, "STM32.TXT", FA_READ) != FR_OK)
        {
          /* 'STM32.TXT' file Open for read Error */
          Error_Handler();
        }
        else
        {
          /* Read data from the text file */
          res = f_read(&MyFile, rtext, sizeof(rtext), (void *)&bytesread);
          
          if((bytesread == 0) || (res != FR_OK))
          {
            /* 'STM32.TXT' file Read or EOF Error */
            Error_Handler();
          }
          else
          {
            /* Close the open text file */
            f_close(&MyFile);
            
            /* Compare read data with the expected data */
            if((bytesread != byteswritten))
            {                
              /* Read data is different from the expected data */
              Error_Handler();
            }
            else
            {
              /* Success of the demo: no error occurrence */
              BSP_LED_On(LED3);
            }
          }
        }
      }
    }
  }          /* Unlink the USB disk I/O driver */
  FATFS_UnLinkDriver(USBDISKPath);

}

/* USER CODE END 0 */

②主循环添加应用程序   

/* USER CODE BEGIN 3 */
        switch(Appli_state)
    {
        case APPLICATION_READY:
            MSC_Application();
            Appli_state = APPLICATION_DISCONNECT;
            break;
        case APPLICATION_DISCONNECT:
            f_mount(NULL, "", 0);
            break;
        default:
            break;

③添加U盘插拔指示灯功能

->初始化位置： 

/* USER CODE BEGIN 2 */
  BSP_LED_Init(LED3);  
  BSP_LED_Init(LED4);

  /* USER CODE END 2 */

-->MSC_Application函数中添加亮灯程序（上面代码中已含）

---->usb_host.c中添加连接断开灭灯功能

static void USBH_UserProcess  (USBH_HandleTypeDef *phost, uint8_t id)
{
  /* USER CODE BEGIN CALL_BACK_1 */
  switch(id)
  {
  case HOST_USER_SELECT_CONFIGURATION:
  break;

  case HOST_USER_DISCONNECTION:
  Appli_state = APPLICATION_DISCONNECT;
    BSP_LED_Off(LED3); 
    BSP_LED_Off(LED4);      
//    f_mount(NULL, (TCHAR const*)"", 0);      

  break;

  case HOST_USER_CLASS_ACTIVE:
  Appli_state = APPLICATION_READY;
  break;

  case HOST_USER_CONNECTION:
  Appli_state = APPLICATION_START;
  break;

  default:
  break;
  }

6、编译，完成

        插上U盘后能够在U盘里面生成txt，并写入内容