Method digitalRead

java/libraries/io/src/processing/io/GPIO.java:177–201

Returns the value of an input pin @param pin GPIO pin @return GPIO.HIGH (1) or GPIO.LOW (0) @see pinMode @see digitalWrite @webref

(int pin)

   *  @webref
   */
  public static int digitalRead(int pin) {
    checkValidPin(pin);

    if (NativeInterface.isSimulated()) {
      return LOW;
    }

    String fn = String.format("/sys/class/gpio/gpio%d/value", pin);
    byte in[] = new byte[2];
    int ret = NativeInterface.readFile(fn, in);
    if (ret < 0) {
      throw new RuntimeException(NativeInterface.getError(ret));
    } else if (1 <= ret && in[0] == '0') {
      return LOW;
    } else if (1 <= ret && in[0] == '1') {
      return HIGH;
    } else {
      System.err.print("Read " + ret + " bytes");
      if (0 < ret) {
        System.err.format(", first byte is 0x%02x" + in[0]);
      }
      System.err.println();
      throw new RuntimeException("Unexpected value");
    }
  }


  /**