[arduino code examples for B16M]-06 How to use SD Card

Code:
/*

 * Made by KinCony IoT: https://www.kincony.com

 *

 * SD Card File Operations

 *

 * This program demonstrates basic file operations on an SD card using the ESP32.

 * It includes functionality to:

 * - Initialize and test the SD card

 * - Read from, write to, append to, and delete files on the SD card

 * - Measure file read and write performance

 *

 * Hardware Connections:

 * - SCK: GPIO 11

 * - MISO: GPIO 12

 * - MOSI: GPIO 10

 * - CS: GPIO 9

 */



#include "FS.h"

#include "SD.h"

#include "SPI.h"



// Pin definitions for SD card

#define SCK  11

#define MISO 12

#define MOSI 10

#define CS   9



/**

 * @brief Reads the contents of a file from the SD card and prints it to the serial monitor.

 * 

 * @param fs File system to use (in this case, SD).

 * @param path Path of the file to read.

 */

void readFile(fs::FS &fs, const char * path) {

  Serial.printf("Reading file: %s\n", path);



  File file = fs.open(path);

  if (!file) {

    Serial.println("Failed to open file for reading");

    return;

  }



  Serial.print("Read from file: ");

  while (file.available()) {

    Serial.print((char)file.read());

  }

  file.close();

}



/**

 * @brief Writes a message to a file on the SD card.

 * 

 * @param fs File system to use (in this case, SD).

 * @param path Path of the file to write.

 * @param message Message to write to the file.

 */

void writeFile(fs::FS &fs, const char * path, const char * message) {

  Serial.printf("Writing file: %s\n", path);



  File file = fs.open(path, FILE_WRITE);

  if (!file) {

    Serial.println("Failed to open file for writing");

    return;

  }

  if (file.print(message)) {

    Serial.println("File written");

  } else {

    Serial.println("Write failed");

  }

  file.close();

}



/**

 * @brief Appends a message to a file on the SD card.

 * 

 * @param fs File system to use (in this case, SD).

 * @param path Path of the file to append.

 * @param message Message to append to the file.

 */

void appendFile(fs::FS &fs, const char * path, const char * message) {

  Serial.printf("Appending to file: %s\n", path);



  File file = fs.open(path, FILE_APPEND);

  if (!file) {

    Serial.println("Failed to open file for appending");

    return;

  }

  if (file.print(message)) {

    Serial.println("Message appended");

  } else {

    Serial.println("Append failed");

  }

  file.close();

}



/**

 * @brief Deletes a file from the SD card.

 * 

 * @param fs File system to use (in this case, SD).

 * @param path Path of the file to delete.

 */

void deleteFile(fs::FS &fs, const char * path) {

  Serial.printf("Deleting file: %s\n", path);

  if (fs.remove(path)) {

    Serial.println("File deleted");

  } else {

    Serial.println("Delete failed");

  }

}



/**

 * @brief Tests file read and write performance.

 * 

 * @param fs File system to use (in this case, SD).

 * @param path Path of the file to test.

 */

void testFileIO(fs::FS &fs, const char * path) {

  File file = fs.open(path);

  static uint8_t buf[512];

  size_t len = 0;

  uint32_t start = millis();

  uint32_t end = start;



  if (file) {

    len = file.size();

    size_t flen = len;

    start = millis();

    while (len) {

      size_t toRead = len;

      if (toRead > 512) {

        toRead = 512;

      }

      file.read(buf, toRead);

      len -= toRead;

    }

    end = millis() - start;

    Serial.printf("%u bytes read for %u ms\n", flen, end);

    file.close();

  } else {

    Serial.println("Failed to open file for reading");

  }



  file = fs.open(path, FILE_WRITE);

  if (!file) {

    Serial.println("Failed to open file for writing");

    return;

  }



  size_t i;

  start = millis();

  for (i = 0; i < 2048; i++) {

    file.write(buf, 512);

  }

  end = millis() - start;

  Serial.printf("%u bytes written for %u ms\n", 2048 * 512, end);

  file.close();

}



void setup() {

  // Initialize serial communication

  Serial.begin(115200);

  

  // Initialize SPI and SD card

  SPIClass spi = SPIClass(HSPI);

  spi.begin(SCK, MISO, MOSI, CS);



  if (!SD.begin(CS, spi, 80000000)) {

    Serial.println("Card Mount Failed");

    return;

  }



  uint8_t cardType = SD.cardType();



  if (cardType == CARD_NONE) {

    Serial.println("No SD card attached");

    return;

  }



  Serial.print("SD Card Type: ");

  if (cardType == CARD_MMC) {

    Serial.println("MMC");

  } else if (cardType == CARD_SD) {

    Serial.println("SDSC");

  } else if (cardType == CARD_SDHC) {

    Serial.println("SDHC");

  } else {

    Serial.println("UNKNOWN");

  }



  uint64_t cardSize = SD.cardSize() / (1024 * 1024);

  Serial.printf("SD Card Size: %lluMB\n", cardSize);

  delay(2000);



  // Perform file operations

  deleteFile(SD, "/hello.txt");

  writeFile(SD, "/hello.txt", "Hello ");

  appendFile(SD, "/hello.txt", "World!\n");

  readFile(SD, "/hello.txt");

  testFileIO(SD, "/test.txt");

  Serial.printf("Total space: %lluMB\n", SD.totalBytes() / (1024 * 1024));

  Serial.printf("Used space: %lluMB\n", SD.usedBytes() / (1024 * 1024));

}



void loop() {

  // No operation in loop

}