static void FS_FileOperations_LIUYAN(void)
{
  FRESULT res; /* FatFs function common result code */
  uint32_t byteswritten, bytesread; /* File write/read counts */
  uint8_t wtext[] = "stm32l476g_eval : This is STM32 working with FatFs and uSD diskio driver"; /* File write buffer */
  uint8_t rtext[100]; /* File read buffer */

  /* Register the file system object to the FatFs module */
  if(f_mount(&SDFatFs, (TCHAR const*)SDPath, 0) == FR_OK)
  {
    /* Create and Open a new text file object with write access */
    if(f_open(&MyFile, "liuyan.TXT", FA_CREATE_ALWAYS | FA_WRITE) == FR_OK)
    {
      /* Write data to the text file */
      res = f_write(&MyFile, wtext, sizeof(wtext), (void *)&byteswritten);

      if((byteswritten > 0) && (res == FR_OK))
      {
        /* Close the open text file */
        f_close(&MyFile);

        /* Open the text file object with read access */
        //f_mount(NULL, (TCHAR const*)SDPath, 0);
      }
    }
  }
  /* Error */
  Error_Handler();
}

int main(void)
{
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_DMA_Init();
  MX_USB_DEVICE_Init();
  MX_SDMMC1_SD_Init();
  MX_FATFS_Init();
  /* USER CODE BEGIN 2 */
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */
    if(HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_9) == 0)
    {
        FS_FileOperations_LIUYAN();
    }
  }
  /* USER CODE END 3 */
}

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : usbd_storage_if.c
  * @version        : v2.0_Cube
  * @brief          : Memory management layer.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2020 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under Ultimate Liberty license
  * SLA0044, the "License"; You may not use this file except in compliance with
  * the License. You may obtain a copy of the License at:
  *                             www.st.com/SLA0044
  *
  ******************************************************************************
  */
/* USER CODE END Header */

/* Includes ------------------------------------------------------------------*/
#include "usbd_storage_if.h"

/* USER CODE BEGIN INCLUDE */
#include "bsp_driver_sd.h"
/* USER CODE END INCLUDE */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/

/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
__IO uint32_t writestatus, readstatus = 0;

/* USER CODE END PV */

/** @addtogroup STM32_USB_OTG_DEVICE_LIBRARY
  * @brief Usb device.
  * @{
  */

/** @defgroup USBD_STORAGE
  * @brief Usb mass storage device module
  * @{
  */

/** @defgroup USBD_STORAGE_Private_TypesDefinitions
  * @brief Private types.
  * @{
  */

/* USER CODE BEGIN PRIVATE_TYPES */

/* USER CODE END PRIVATE_TYPES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_Defines
  * @brief Private defines.
  * @{
  */

#define STORAGE_LUN_NBR                  1
#define STORAGE_BLK_NBR                  0x10000
#define STORAGE_BLK_SIZ                  0x200

/* USER CODE BEGIN PRIVATE_DEFINES */

/* USER CODE END PRIVATE_DEFINES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_Macros
  * @brief Private macros.
  * @{
  */

/* USER CODE BEGIN PRIVATE_MACRO */

/* USER CODE END PRIVATE_MACRO */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_Variables
  * @brief Private variables.
  * @{
  */

/* USER CODE BEGIN INQUIRY_DATA_FS */
/** USB Mass storage Standard Inquiry Data. */
const int8_t STORAGE_Inquirydata_FS[] = {/* 36 */
 
  /* LUN 0 */
  0x00,
  0x80,
  0x02,
  0x02,
  (STANDARD_INQUIRY_DATA_LEN - 5),
  0x00,
  0x00,
  0x00,
  'S', 'T', 'M', ' ', ' ', ' ', ' ', ' ', /* Manufacturer : 8 bytes */
  'P', 'r', 'o', 'd', 'u', 'c', 't', ' ', /* Product      : 16 Bytes */
  ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
  '0', '.', '0' ,'1'                      /* Version      : 4 Bytes */
};
/* USER CODE END INQUIRY_DATA_FS */

/* USER CODE BEGIN PRIVATE_VARIABLES */

/* USER CODE END PRIVATE_VARIABLES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Exported_Variables
  * @brief Public variables.
  * @{
  */

extern USBD_HandleTypeDef hUsbDeviceFS;

/* USER CODE BEGIN EXPORTED_VARIABLES */
extern SD_HandleTypeDef hsd1;
/* USER CODE END EXPORTED_VARIABLES */

/**
  * @}
  */

/** @defgroup USBD_STORAGE_Private_FunctionPrototypes
  * @brief Private functions declaration.
  * @{
  */

static int8_t STORAGE_Init_FS(uint8_t lun);
static int8_t STORAGE_GetCapacity_FS(uint8_t lun, uint32_t *block_num, uint16_t *block_size);
static int8_t STORAGE_IsReady_FS(uint8_t lun);
static int8_t STORAGE_IsWriteProtected_FS(uint8_t lun);
static int8_t STORAGE_Read_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
static int8_t STORAGE_Write_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len);
static int8_t STORAGE_GetMaxLun_FS(void);

/* USER CODE BEGIN PRIVATE_FUNCTIONS_DECLARATION */

/* USER CODE END PRIVATE_FUNCTIONS_DECLARATION */

/**
  * @}
  */

USBD_StorageTypeDef USBD_Storage_Interface_fops_FS =
{
  STORAGE_Init_FS,
  STORAGE_GetCapacity_FS,
  STORAGE_IsReady_FS,
  STORAGE_IsWriteProtected_FS,
  STORAGE_Read_FS,
  STORAGE_Write_FS,
  STORAGE_GetMaxLun_FS,
  (int8_t *)STORAGE_Inquirydata_FS
};

/* Private functions ---------------------------------------------------------*/
/**
  * @brief  Initializes over USB FS IP
  * @param  lun:
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_Init_FS(uint8_t lun)
{
  /* USER CODE BEGIN 2 */
  BSP_SD_Init();
  return (USBD_OK);
  /* USER CODE END 2 */
}

/**
  * @brief  .
  * @param  lun: .
  * @param  block_num: .
  * @param  block_size: .
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_GetCapacity_FS(uint8_t lun, uint32_t *block_num, uint16_t *block_size)
{
  /* USER CODE BEGIN 3 */
  HAL_SD_CardInfoTypeDef info;
  int8_t ret = -1;

  if(BSP_SD_IsDetected() != SD_NOT_PRESENT)
  {
    BSP_SD_GetCardInfo(&info);

    *block_num =  info.LogBlockNbr  - 1;
    *block_size = info.LogBlockSize;
    ret = 0;
  }
  return ret;
  /* USER CODE END 3 */
}

/**
  * @brief  .
  * @param  lun: .
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_IsReady_FS(uint8_t lun)
{
  /* USER CODE BEGIN 4 */
  static int8_t prev_status = 0;
  int8_t ret = -1;

  if(BSP_SD_IsDetected() != SD_NOT_PRESENT)
  {
    if(prev_status < 0)
    {
      BSP_SD_Init();
      prev_status = 0;

    }
    if(BSP_SD_GetCardState() == SD_TRANSFER_OK)
    {
      ret = 0;
    }
  }
  else if(prev_status == 0)
  {
    prev_status = -1;
  }
  return ret;
  /* USER CODE END 4 */
}

/**
  * @brief  .
  * @param  lun: .
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_IsWriteProtected_FS(uint8_t lun)
{
  /* USER CODE BEGIN 5 */
  return (USBD_OK);
  /* USER CODE END 5 */
}

/**
  * @brief  .
  * @param  lun: .
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_Read_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len)
{
  /* USER CODE BEGIN 6 */
  int8_t ret = -1;
  uint32_t timeout = 100000;

  BSP_SD_ReadBlocks((uint32_t *)buf, blk_addr, blk_len, SD_DATATIMEOUT);
  while(BSP_SD_GetCardState() != SD_TRANSFER_OK)
  {
    if (timeout-- == 0)
    {
      return ret;
    }
  }
  ret = 0;

  return ret;
  /* USER CODE END 6 */
}

/**
  * @brief  .
  * @param  lun: .
  * @retval USBD_OK if all operations are OK else USBD_FAIL
  */
int8_t STORAGE_Write_FS(uint8_t lun, uint8_t *buf, uint32_t blk_addr, uint16_t blk_len)
{
  /* USER CODE BEGIN 7 */
  int8_t ret = -1;
  uint32_t timeout = 100000;

  BSP_SD_WriteBlocks((uint32_t *)buf, blk_addr, blk_len, SD_DATATIMEOUT);
  while(BSP_SD_GetCardState() != SD_TRANSFER_OK)
  {
    if (timeout-- == 0)
    {
      return ret;
    }
  }
  ret = 0;

  return ret;
  /* USER CODE END 7 */
}

/**
  * @brief  .
  * @param  None
  * @retval .
  */
int8_t STORAGE_GetMaxLun_FS(void)
{
  /* USER CODE BEGIN 8 */
  return (STORAGE_LUN_NBR - 1);
  /* USER CODE END 8 */
}

/* USER CODE BEGIN PRIVATE_FUNCTIONS_IMPLEMENTATION */
//void BSP_SD_WriteCpltCallback(void)
//{
//  writestatus = 1;
//}
//
//void BSP_SD_ReadCpltCallback(void)
//{
//  readstatus = 1;
//}

/* USER CODE END PRIVATE_FUNCTIONS_IMPLEMENTATION */

/**
  * @}
  */

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/