# STM32H7S78-DK Development Kit Three-week Review: Implementation and Analysis of Simple Sound Collection and Storage Using SD Card Reading and Writing

ccccccc@ · Published on 2024-10-31 17:34

# STM32H7S78-DK Development Kit Three-week Review: Implementation and Analysis of Simple Sound Collection and Storage Using SD Card Reading and Writing [Copy link]

This project includes functions such as saving recordings, key control, serial port control, frequency component analysis and classification, etc., which are completed step by step. First, open the SD card to read and write. In embedded development, especially in a bare metal environment without an operating system, the SD card is an important component for realizing large-capacity data storage. ## 1. Hardware connection Before starting CubeMX configuration, you need to understand the pin configuration first. 
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 ### 1.1 Data pin connection 
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 - **D0 - D3**: Connect the data pins D0-D3 of the SD card to PC8, PC9, PC10, and PC11 of the STM32 respectively. - **CMD**: Connect the CMD pin of the SD card to PD2 of the STM32 for command transmission. - **CLK**: Connect the CLK pin of the SD card to PC12 of the STM32 to provide a clock signal. - **SD_Detect**: Connect the SD_Detect pin of the SD card to GPIO (PM14) to detect the SD card insertion status. Specific connection example code: ```c // Configure pins, which can be seen in the initialization code generated in CubeMX void MX_GPIO_Init(void) { GPIO_InitTypeDef GPIO_InitStruct = {0}; // Enable clock for GPIOC and GPIOD __HAL_RCC_GPIOC_CLK_ENABLE(); __HAL_RCC_GPIOD_CLK_ENABLE(); __HAL_RCC_GPIOM_CLK_ENABLE(); // Enable the GPIO clock of PM14 pin // Configure SDMMC pins: CMD (PD2), CLK (PC12), D0 (PC8), D1 (PC9), D2 (PC10), D3 (PC11) GPIO_InitStruct.Pin = GPIO_PIN_8 | GPIO_PIN_9 | GPIO_PIN_10 | GPIO_PIN_11 | GPIO_PIN_12 | GPIO_PIN_2; GPIO_InitStruct.Mode = GPIO_MODE_AF_PP; GPIO_InitStruct.Pull = GPIO_NOPULL; GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH; GPIO_InitStruct.Alternate = GPIO_AF12_SDMMC1; HAL_GPIO_Init(GPIOC, &GPIO_InitStruc t); // Configure SD_Detect pin (PM14) GPIO_InitStruct.Pin = GPIO_PIN_14; GPIO_InitStruct.Mode = GPIO_MODE_INPUT; GPIO_InitStruct.Pull = GPIO_PULLUP; // Internal pull-up resistor HAL_GPIO_Init(GPIOM, &GPIO_InitStruct); } ``` ## 2. CubeMX configuration and code implementation CubeMX can simplify the configuration of SD card and file system. We will use it to generate the initialization code of SD card and use FATFS file system to implement file operation. In addition to the simple and fast configuration, the FATFS file system method selected here has some disadvantages of using eprom: 1. Without file system, SD card cannot be read by computer and other devices. 2. Slow reading and writing speed and small reading and writing area. ### 2.1 CubeMX configuration steps#### 2.1.1 SDMMC interface settings 1. Open **Peripherals -> SDMMC1** interface in CubeMX. 2. Set its mode to **4-bit** mode to increase data transmission rate. 3. Adjust the clock frequency of SDMMC1 to 48MHz in **Clock Configuration** to ensure transmission rate and stability. #### 2.1.2 Enable FATFS file system 1. Enable FATFS support in **Middlewares** and select SDMMC1 as the interface to implement file system-based operations. 2. Generate initialization code, where the `fatfs.c` file contains the basic interface for file system initialization and reading and writing. ### 2.2 Basic code example Next, use the FATFS file system to create, write and read files on the SD card: ```c #include "fatfs.h" #include "sdmmc.h" #include<stdio.h>

void SD_Test() { FATFS fs; FIL file; FRESULT res; UINT bw; // Mount file system res = f_mount(&fs, "0:", 1); if (res == FR_OK) { // Create and write Enter file res = f_open(&file, "0:/test.txt", FA_CREATE_ALWAYS | FA_WRITE); if (res == FR_OK) { char writeData[] = "Hello, SD Card!"; f_write(&file, writeData, sizeof (writeData), &bw); f_close(&file); } // Read the file res = f_open(&file, "0:/test.txt", FA_READ); if (res == FR_OK) { char readData[32]; f_read(&file, readData, sizeof(readData), &bw); printf("Read data: %s\n", readData); f_close(&file); } // Unmount the file system f_mount(NULL, "0:", 1); } } ``` ## 3. Different SD card reading and writing methods and code analysis Of course, in different scenarios and requirements, the reading and writing of SD cards The operation should be changed appropriately to improve efficiency and save resources. ### 3.1 Standard read and write based on file system - **Advantage**: CubeMX automatically generates FATFS code, simplifies the file operation process, and is suitable for low-frequency storage. For example, sensors Data recording, etc. - **Disadvantages**: Since the file system requires indexing and management structure, the writing speed will be affected. ```c void SD_WriteRead_FileSystem() { FATFS fs; FIL file; UINT bw, br; char writeData[] = "File System Write Test"; char readData[32]; // Mount the file system f_mount(&fs, "0 :", 1); // Write to file f_open(&file, "0:/filesystem.txt", FA_CREATE_ALWAYS | FA_WRITE); f_write(&file, writeData, sizeof(writeData), &bw); f_close(&file); // Read file f_open(&file, "0:/filesystem.txt", FA_READ); f_read(&file, readData, sizeof(readData), &br); f_close(&file); printf("Read Data: %s\n", readData); f_mount(NULL, "0:", 1); } ``` ### 3.2 Sector-level block read and write **Advantages**: Directly operate sectors to avoid file system overhead, suitable for high-frequency data writing. For example, audio and video, network files, etc. - **Disadvantages**: Manual management of data location and sector allocation is required, programming difficulty big. ```c void SD_WriteBlock(uint32_t sector, uint8_t *data, uint32_t count) { if (HAL_SD_WriteBlocks(&hsd1, data, sector, count, HAL_MAX_DELAY) == HAL_OK) { printf("Block write success!\n"); } } void SD_ReadBlock(uint32_t sector, uint8_t *data, uint32_t count) { if (HAL_SD_ReadBlocks(&hsd1, data, sector, count, HAL_MAX_DELAY) == HAL_OK) { printf("Block read success!\n"); } } `` ` ### 3.3 Cache + file system hybrid mode - **Advantages**: Use cache to reduce frequent writes, improve write efficiency, suitable for continuous data storage such as audio. - **Disadvantages**: Takes up more RAM resources, System memory limitations need to be considered. ```c #define BUFFER_SIZE 512 uint8_t cacheBuffer[BUFFER_SIZE]; void SD_WriteCache(const char *data) { static uint32_t offset = 0; while (*data) { cacheBuffer[offset++] = *data++; if (offset >= BUFFER_SIZE) { SD_WriteBlock(0, cacheBuffer, BUFFER_SIZE / 512); // Write in blocks offset = 0; } } } ``` ## 4. Optimization of audio data storage Considering that recording is a time-sensitive process Operation, so the storage efficiency is very high, the following are two optimization solutions. ### 4.1 Double buffering technology Set up two buffers and write to the SD card alternately to reduce the write delay. ```c uint8_t bufferA[BUFFER_SIZE]; uint8_t bufferB[BUFFER_SIZE]; volatile uint8_t *currentBuffer = bufferA; void Audio_WriteToSD() { if (currentBuffer == bufferA) { SD_WriteBlock(0, bufferA,BUFFER_SIZE / 512); currentBuffer = bufferB; } else { SD_WriteBlock(0, bufferB, BUFFER_SIZE / 512); currentBuffer = bufferA; } } ``` ### 4.2 File Segment Storage Audio data is stored in segments by time or size to avoid the overhead caused by large file operations. ```c void SaveAudioSegment(uint8_t *data, size_t size, uint8_t segmentNum) { char filename[20]; sprintf(filename, " audio_segment_%d.wav", segmentNum); f_open(&file, filename, FA_CREATE_ALWAYS | FA_WRITE); f_write(&file, data, size, &bw); f_close(&file); } ```</stdio.h>

cc1989summer

Dude, this post of yours is just a bunch of nonsense, there is no actual picture of the development board running.

ccccccc@

cc1989summer posted on 2024-11-2 13:03 Buddy, you are just talking in this post, there is no actual picture of the development board running.

Add later, hahahaha

# STM32H7S78-DK Development Kit Three-week Review: Implementation and Analysis of Simple Sound Collection and Storage Using SD Card Reading and Writing [Copy link]

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