Wiring
Check pinout, power supply, common GND and voltage levels before connecting the module.
Full code
#include <SPI.h>
#include <SD.h>
const int chipSelect = 10;
void setup() {
Serial.begin(9600);
if (!SD.begin(chipSelect)) return;
File file = SD.open("log.txt", FILE_WRITE);
if (file) {
file.println("Hello from Arduino");
file.close();
}
}
void loop() {}How it works
This lesson matches the page title and gives a clean starting point for this exact example.
Common mistakes
Check board selection, wiring, libraries, power supply and serial monitor baud rate.