#include File f; void setup() { Serial.begin(9600); Serial.print("Initializing SD card..."); SD.begin(); Serial.println("done."); f = SD.open("test.txt", true, false); if (f) { Serial.print("Writing to test.txt..."); f.println("testing 1, 2, 3."); f.close(); Serial.println("done."); } else { Serial.println("error opening test.txt"); } f = SD.open("test.txt"); if (f) { Serial.println("test.txt:"); while (f.available()) Serial.write(f.read()); f.close(); } else { Serial.println("error opening test.txt"); } } void loop() { }