I have an Arduino Mega 2560 where I have used a MicroSD Card Module to Read/Write Data on the Micro SD Card. I have tried using the Example in the Arduino IDE but the data is not being written or read by Arduino to the SD Card Module. The connections with the module is exactly how it is described in the Sketch. I have attached pictures of the Connection and the module I use for the same.

The Example sketch for the SD Card Read/Write is also attached.

If there is a problem that you can notice, please let me know what the problem is and if it can be solved.

Thank you in advance.

SD card read/write

This example shows how to read and write data to and from an SD card file
The circuit:
* SD card attached to SPI bus as follows:
** MOSI - pin 11
** MISO - pin 12
** CLK - pin 13
** CS - pin 4 (for MKRZero SD: SDCARD_SS_PIN)

created   Nov 2010
by David A. Mellis
modified 9 Apr 2012
by Tom Igoe

This example code is in the public domain.


#include <SPI.h>
#include <SD.h>

 File myFile;

 void setup() {
 // Open serial communications and wait for port to open:
     while (!Serial) {
        ; // wait for serial port to connect. Needed for native USB port only

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

 if (!SD.begin(4)) {
 Serial.println("initialization failed!");

  Serial.println("initialization done.");

  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
   myFile = SD.open("test.txt", FILE_WRITE);

  // if the file opened okay, write to it:
    if (myFile) {
    Serial.print("Writing to test.txt...");
    myFile.println("testing 1, 2, 3.");
    // close the file:
     } else {
     // if the file didn't open, print an error:
     Serial.println("error opening test.txt");

    // re-open the file for reading:
  myFile = SD.open("test.txt");
  if (myFile) {

    // read from the file until there's nothing else in it:
     while (myFile.available()) {
    // close the file:
     } else {
    // if the file didn't open, print an error:
    Serial.println("error opening test.txt");

    void loop() {
   // nothing happens after setup

Connection with Arduino SD Card Module

1 Answer 1


The SPI wiring described in the SD card example sketch is for Uno. On Mega the SPI pins are 50 MISO, 51 MOSI and 52 CLK.

  • Is it possible to use 50 MISO, 51 MOSI and 52 CLK and 53 for CS?
    – Keshav K
    Dec 1, 2018 at 13:27
  • SD.begin(53); for 53 as CS for SD card
    – Juraj
    Dec 1, 2018 at 17:45
  • Thank you so much. I will check with your information and update you.
    – kevin_444
    Dec 2, 2018 at 10:08
  • I am so sorry for the delay. I had tried it and it worked. I could not come back go StackExchange because of getting stuck with other projects. Thank you so much for your help.
    – kevin_444
    Jan 19, 2019 at 7:26

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