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

pinMode()

Examples
import processing.io.*;

// On the Raspberry Pi GPIO 4 is physical pin 7 on the header

void setup() {
  // INPUT_PULLUP enables the built-in pull-up resistor for this pin
  // left alone, the pin will read as HIGH
  // connected to ground (via e.g. a button or switch) it will read LOW
  GPIO.pinMode(4, GPIO.INPUT_PULLUP);
}

void draw() {
  if (GPIO.digitalRead(4) == GPIO.LOW) {
    // button is pressed
    fill(255);
  } else {
    // button is not pressed
    fill(204);
  }
  stroke(255);
  ellipse(width/2, height/2, width*0.75, height*0.75);
}

Description Configures a pin to act either as input (INPUT), or input with internal pull-up resistor (INPUT_PULLUP), or input with internal pull-down resistor (INPUT_PULLDOWN) or output (OUTPUT)

Unlike on Arduino, where pins are implicitly set to inputs by default, it is necessary to call this function for any pin you want to access, including input pins.

Pull-up and pull-down resistors are very useful when connecting buttons and switches, since they will force the value of the pin in a specified electrical state when no electrical connection is made, and the pin would otherwise be left "floating".

The ability to set (and clear) pull-up and pull-down resistors is currently limited to the Raspberry Pi running the Raspbian distribution. On other systems, a warning will be shown.
Syntax
.pinMode(pin, mode)
Parameters
pin int: GPIO pin
mode int: GPIO.INPUT, GPIO.INPUT_PULLUP, GPIO.INPUT_PULLDOWN, or GPIO.OUTPUT
Returnsvoid
Updated on October 2, 2018 05:02:13pm EDT

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