STM32 U盘drive开发笔记

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1. 首先在cube里面选用USB OTG, fats 文件系统

2. 在main函数里面初始化和USB消息轮询:

int main(void)
{
    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    if (MX_FATFS_Init() != APP_OK)   
        Error_Handler();

    MX_USB_Host_Init();
    while (1)
    {
        MX_USB_HOST_Process();
        switch (Appli_state)
        {

            case APPLICATION_START:
                Appli_state = APPLICATION_DISCONNECT;
                break;

            case APPLICATION_READY:
                read_write_U_disk_file_data();
                Appli_state = APPLICATION_DISCONNECT;
                break;

            case APPLICATION_DISCONNECT:
                f_mount(NULL, "", 0);
                break;

            default:
                break;
        }
    }
}

 初始化:

USBH_HandleTypeDef hUsbHostFS;
ApplicationTypeDef Appli_state = APPLICATION_IDLE;

void MX_USB_Host_Init(void)
{
    if (USBH_Init(&hUsbHostFS, USBH_UserProcess, HOST_FS) != USBH_OK)
    {
        Error_Handler();
    }
    if (USBH_RegisterClass(&hUsbHostFS, USBH_MSC_CLASS) != USBH_OK)
    {
        Error_Handler();
    }
    if (USBH_Start(&hUsbHostFS) != USBH_OK)
    {
        Error_Handler();
    }
}

 MX_USB_HOST_Process();  是获取到U盘的状态

void MX_USB_HOST_Process(void)
{
    USBH_Process(&hUsbHostFS);
}

static void USBH_UserProcess(USBH_HandleTypeDef *phost, uint8_t id)
{
    switch (id)
    {
        case HOST_USER_SELECT_CONFIGURATION:
            break;

        case HOST_USER_DISCONNECTION:
            Appli_state = APPLICATION_DISCONNECT;
            break;

        case HOST_USER_CLASS_ACTIVE:
            Appli_state = APPLICATION_READY;
            break;

        case HOST_USER_CONNECTION:
            Appli_state = APPLICATION_START;
            break;

        default:
            break;
    }
}

当收到的消息是: 

1. HOST_USER_CLASS_ACTIVE,  表明U盘驱动和文件系统已经可以读出文件了, 执行: read_write_U_disk_file_data();

2. HOST_USER_DISCONNECTION和HOST_USER_CONNECTION 表示u盘的拔插

* read_write_U_disk_file_data(); 里面怎样读文件:

FATFS fatfs;
FIL file;
DIR dir;
FILINFO fileInfo;

static void MSC_Application(void)
{
    FRESULT res;
    res = f_mount(&fatfs, "0:/", 1);
    if (res != FR_OK)
    { // 无法挂载文件
        f_mount(NULL, "", 0);
        return;
    }
    res = f_opendir(&dir, "0:/");
    if (res != FR_OK)
    { // 无法打开目录
        f_mount(NULL, "", 0);
        return;
    }

    while ((f_readdir(&dir, &fileInfo) == FR_OK) && (fileInfo.fname[0] != '\0'))
    {
        if (fileInfo.fattrib & AM_DIR)
        {
            continue;
        }

        if (0 == strcmp(fileInfo.altname, "readme.bin"))  
        {
            res = f_open(&file, fileInfo.altname, FA_READ);
            if (res != FR_OK)
            { // 无法打开文件
                f_mount(NULL, "", 0);
                return;
            }
            user_read_bin(&file);    
            f_closedir(&dir);
            f_mount(NULL, "", 0);
        }
    }
    f_closedir(&dir);
    f_mount(NULL, "", 0);
}

uint8_t user_read_bin(FIL *file)
{
    uint8_t ret = 0;
    UINT bytes_read;
    uint8_t ucAppPageBufer[1024]

    while (((ret = f_read(file, ucAppPageBufer, 1024, &bytes_read)) == FR_OK) 
             && (bytes_read > 0))
    {
        // 处理读取的数据, 存在ucAppPageBufer里面, 1024个byte'

    }



    f_close(file);
    f_mount(NULL, "", 0);
    return ret;
}

上面的函数就是示例怎样读出bin文件的.

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