1 Introduction

This article will introduce how to use the CubeMx tool to create an SD card-based file system from scratch, for reference by those who will use this function in the future.

2 Preparation

The test of this project will use the STM3240G-EVAL, the official evaluation board of ST, as the test platform. It is necessary to first understand the connection methods of some external components of this board.

 
 
LED1~LED4 use pins PG6, PG8, PI9, PC7 respectively, output high level LED lights, user button uses PG15 pin, when pressed, it is low level. 
 
 
As shown in the figure above, the HSE used by MCU is 25M crystal oscillator. SD card uses 6 fixed pins of STM32F407 as shown in the figure above: D0 (PC8), D1 (PC9), D2 (PC10), D3 (PC11), CLK (PC12), CMD (PD2). The SD card insertion detection pin is a user-defined pin, and the PH13 pin is used on the STM3240G, the official evaluation board of ST.

3. Create CubeMx project and modify code

3.1 Create CubeMx project

Open CubeMx and create a project based on STM32F407IGHx, enable HSE of RCC, external crystal mode, and SDIO uses 4-bit bus width, as shown in the figure below: 
 
 
Set PH13 to INPUT mode on the right side of pinout: 
 
Next, configure the clock tree and configure the main screen to 168M: 

The configuration on the configuration page is shown in the figure below: 
 
Add SD Card type FATFS in the middleware: 
 
Use the default parameter values ​​for the file system related parameter configurations in the configuration. 
Another very important point is to configure the stack size to 0x800 in the project settings. The default 0x400 is not enough and an error will occur during runtime. As shown below: 
 
Finally, click Generate Code.

3.2 SD card and file system initialization

The main function contains the following code:

  MX_GPIO_Init(); MX_SDIO_SD_Init(); MX_FATFS_Init();12341234

The SDIO initialization code has been automatically generated. No modification is required. Enter the MX_FATFS_Init() function and add user-defined code between /* USER CODE BEGIN Init / and / USER CODE END Init */ as follows:

/* USER CODE BEGIN Variables */FATFS SDFatFs;/* USER CODE END Variables */ void MX_FATFS_Init(void)
{ /*## FatFS: Link the SD driver ###########################*/
  retSD = FATFS_LinkDriver(&SD_Driver, SD_Path); /* USER CODE BEGIN Init */
  /* additional user code for init */
    if(f_mount(&SDFatFs, (TCHAR const*)SD_Path, 0) != FR_OK)
    { /* FatFs Initialization Error */
      Error_Handler();
    } else
    {// if(f_mkfs((TCHAR const*)SD_Path, 0, 0) != FR_OK) //Format SD memory card// {// /* FatFs Format Error */// Error_Handler();// }
    } /* USER CODE END Init */}12345678910111213141516171819202122232425261234567891011121314151617181920212223242526

As shown in the above code, define the global variable SDFatFs for subsequent code. 
The commented out f_mkfs line after mounting the SD card in the above code is to format the SD card. You can decide whether to format the SD card according to the situation. Here, choose not to format it.

3.3 File system and SDIO connection part

Some parts of the file system and SDIO need to be modified. 
Open the bsp_driver_sd.c file and find the BSP_SD_IsDetected function. Since the SD card insertion detection is implemented through the user-defined pin (in this case, it is detected through PH13), it is necessary to match it here. Add your own code between /* USER CODE BEGIN 1 / and / USER CODE END 1 */ in this function:

uint8_t BSP_SD_IsDetected(void)
{
  __IO uint8_t status = SD_PRESENT; /* USER CODE BEGIN 1 */
  /* user code can be inserted here */
  if(HAL_GPIO_ReadPin(SD_DETECT_GPIO_Port, SD_DETECT_Pin) != GPIO_PIN_RESET) //Low level when SD card is inserted
    {
        status =SD_NOT_PRESENT;
    } /* USER CODE END 1 */     

  return status;
}123456789101112131415123456789101112131415

That's it, the transplant is done, the next step is to write the test code.

3.4 Testing the File System

Go back to the main function and add your own file system test code between /* USER CODE BEGIN 2 / and / USER CODE END 2 */ as follows:

if(f_open(&MyFile, "STM32.TXT", FA_CREATE_ALWAYS | FA_WRITE) != FR_OK) //Create a file
    { /* 'STM32.TXT' file Open for write Error */
        Error_Handler();
    } else
  {
            res = f_write(&MyFile, wtext, sizeof(wtext), (void *)&byteswritten); //Write content
            if((byteswritten == 0) || (res != FR_OK))
            { /* 'STM32.TXT' file Write or EOF Error */
                Error_Handler();
            } else
            {
                f_close(&MyFile); //Close the file

                /*##-7- Open the text file object with read access ###############*/
                if(f_open(&MyFile, "STM32.TXT", FA_READ) != FR_OK) //Open the file again
                { /* 'STM32.TXT' file Open for read Error */
                    Error_Handler();
                } else
                {
                    res = f_read(&MyFile, rtext, sizeof(rtext), (UINT*)&bytesread); //Read content

                    if((bytesread == 0) || (res != FR_OK))
                    { /* 'STM32.TXT' file Read or EOF Error */
                        Error_Handler();
                    } else
                    {
                        f_close(&MyFile); //Close the file

                /*##-10- Compare read data with the expected data ############*/
                if((bytesread != byteswritten)) //Compare
                { /* Read data is different from the expected data */
                  Error_Handler();
                } else
                { /* Success of the demo: no error occurrence */
                  HAL_GPIO_WritePin(LED1_GPIO_Port,LED1_Pin,GPIO_PIN_SET);
                }
                    }
                }
            }
  }123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051521234567891011121314151617 1819202122232425262728293031323334353637383940414243444546474849505152

The above code flow is: create a file, write content, close the file, then open the file again, read the content, close the file, and finally compare whether the read content is the written content, and process it according to the comparison result.

Finally, compile the entire project and burn it to the STM3240G-EVAL evaluation board for testing. The running result is OK.

4 Conclusion

CubeMx is quite powerful. It can automatically generate a project by setting up a file system of an SD memory card in a few steps. You only need to modify a few key places to complete such a seemingly complex project in a few simple steps. CubeMx is a very powerful tool. The most critical parameter in this article is the stack size set to 0x800. People who have never encountered this problem will take a long time to discover this problem, so I emphasize it again.

Finally, the code project download link address is attached: 
http://download.csdn.net/detail/flydream0/9649702