ESP32 - SD Card

/*

  SD Card Interface code for ESP32

  SPI Pins of ESP32 SD card as follows:

  CS    = 5;

  MOSI  = 23;

  MISO  = 19;

  SCK   = 18; 

*/

#include <SPI.h>

#include <SD.h>

File myFile;

const int CS = 5;

//WriteFile

void WriteFile(const char * path, const char * message){

  // open the file.

  // Note - only one file can be open at a time

  // close the opened file before opening another file

  myFile = SD.open(path, FILE_WRITE);

  // if the file open fine, then write to the file

  if (myFile) {

    myFile.println(message);

    myFile.close(); // close the file

    Serial.println("completed.");

  } 

  // if the file didn't open then print an error

  else {

    Serial.println("error opening file ");

    Serial.println(path);

  }

}

//ReadFile

void ReadFile(const char * path){

  // open the file for reading:

  myFile = SD.open(path);

  if (myFile) {

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

     // read from the file until there's nothing else in it:

    while (myFile.available()) {

      Serial.write(myFile.read());

    }

    myFile.close(); // close the file

  } 

  else {

    // if the file didn't open then print an error

    Serial.println("error opening test.txt");

  }

}

void setup() {

  Serial.begin(9600);

  delay(500);

  while (!Serial) { ; }  // wait for serial port to connect

  Serial.println("Initializing SD card...");

  if (!SD.begin(CS)) {

    Serial.println("initialization failed!");

    return;

  }

  Serial.println("initialization done.");

  WriteFile("/test.txt", "Cheers 2 Engineering - SD Card test");

  ReadFile("/test.txt");

}

void loop() {

  // nothing happens after setup

}