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This example is for Wiring version 1.0 build 0100+. If you have a previous version, use the examples included with your software. If you see any errors or have comments, please let us know.

Simple Read
Read data from the serial port and turn ON the onboard LED if the character received is an 'a' For the Wiring boards v1 the on-board LED is on pin 48, on Wiring S the on-board LED is on pin 15.

    int data; // to read the char

    void setup()
    {
      Serial.begin(9600);
      pinMode(WLED, OUTPUT);
    }

    void loop()
    {
      if (Serial.available())       // if data available
      {
        data = Serial.read();       // read data
        if (data == 'a')            // if value read is character 'a'
        {
          digitalWrite(WLED, HIGH); // turn ON the onboard LED
        }
        else
        {
          digitalWrite(WLED, LOW);  // if not turn it OFF
        }
      }
      delay(100); // wait 100ms for next read
    }