Read byte from Serial port and set pin
This code run on Arduino Due, read byte from Serial port, and set LED pin HIGH/LOW according. int led = 13; int incomingByte = 0; void setup() { pinMode(led, OUTPUT); //Setup Serial Port with baud rate of 115200 Serial.begin(115200); Serial.println("Press H to turn LED ON"); Serial.println("Press L to turn LED OFF"); } void loop() { if (Serial.available() > 0) { // read the incoming byte: incomingByte = Serial.read(); if(incomingByte == 'H'){ digitalWrite(led, HIGH); Serial.println("LED ON"); }else if(incomingByte == 'L'){ digitalWrite(led, LOW); Serial.println("LED OFF"); }else{ Serial.println("invalid!"); } } }