Digital output

Digital output happens on a pin when the an output voltage is set on it that is either at “high” or “low” level. When you write to a digital pin in your program, these voltage levels are written by setting boolean values of true for high and false for low.

Pins on edge of board

Logic levels

Whether a pin output level is high or low depends on how the microcontroller on the Adafruit Circuit Playground Express sets the voltage level for each. This is somewhere near the supply voltage for high (the voltage at the 3.3V pin) and near ground voltage for low (the voltage at GND pin, or 0V). Also, when a digital output is used for writing data, the output level means that a binary value of 1 is high and 0 is low. Multiple digital outputs are often combined in digital electronics to write larger values of binary numbers. Here’s the relationship between output voltage, logic value, and binary value:

Voltage Logic Binary
0 v false 0
3.3 v true 1


There are several experiments to let you test out the concepts you learn in the digital output sections. You’ll need a few things to in order to perform some of the experiments.


  "name": "On and off signalling",
  "description": "Send out an on and off signal from a pin.",
}, {
  "name": "Pulses and triggers",
  "description": "Make notification signals and trigger pin events.",
}, {
  "name": "Digital data",
  "description": "Send and receive binary numbers on the pins.",