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 13
* - MISO: GPIO 14
* - MOSI: GPIO 12
* - CS: GPIO 11
*/
#include "FS.h"
#include "SD.h"
#include "SPI.h"
// Pin definitions for SD card
#define SCK 13
#define MISO 14
#define MOSI 12
#define CS 11
/**
* @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
}
