- Processing
- p5.js
- Processing.py
- Processing for Android
- Processing for Pi

- Processing Foundation

This reference is for Processing 3.0+. If you have a previous version, use the reference included with your software in the Help menu. If you see any errors or have suggestions, please let us know. If you prefer a more technical reference, visit the Processing Core Javadoc and Libraries Javadoc.

Class | GPIO
Name | ### releasePin()
Examples |
    import processing.io.*;
    boolean ledOn = false;

    void setup() {
      GPIO.pinMode(4, GPIO.OUTPUT);

      // On the Raspberry Pi, GPIO 4 is pin 7 on the pin header,
      // located on the fourth row, above one of the ground pins

      frameRate(0.5);
    }

    void draw() {
      ledOn = !ledOn;
      if (ledOn) {
        GPIO.digitalWrite(4, GPIO.LOW);
      } else {
        GPIO.digitalWrite(4, GPIO.HIGH);
      }
    }

    // cleanup on keypress
    void keyPressed() {
      GPIO.releasePin(4);
      exit();
    }
Description | Gives ownership of a pin back to the operating system Without calling this function, the pin will remain in the current state even after the sketch has been closed.
Syntax |
    .releasePin(pin)
Parameters |
pin | int: GPIO pin
Returns | void

Updated on July 4, 2018 11:56:46am EDT