Digital Output

Let's blink a LED!

Here's the bread board layout. The resistor can be something around 1kOhm. We don't need to make the LED super bright.

And here's a complete blink program you can run to make the LED blink forever.

import time
import board
import digitalio

led = digitalio.DigitalInOut(board.GP17)
led.direction = digitalio.Direction.OUTPUT

while True:
    led.value = True
    time.sleep(0.5)
    led.value = False
    time.sleep(0.5)

Digital Input

Let's read a button!

The cool thing here is that the Pico has internal pull up resistors. Therefore we don't need to add any additional external resistors, which you might see in some other wiring diagrams. The equivalent resistor is inside the Pico!

Here's the breadboard layout.

Here's the code to run. It will continuously print the button state.

  • True = not pressed
  • False = pressed
import board
import digitalio

button = digitalio.DigitalInOut(board.GP16)
button.direction = digitalio.Direction.INPUT
button.pull = digitalio.Pull.UP

while True:
    print(button.value)

Digital Input and Output

Ok, let's put those two together and make the button turn on the LED. So we'll use two digital pins - one will be an input (button) and one will be an output (LED).

Here's the bread board layout.

And here's the code. Note how the code uses not to invert the button logic.

import board
import digitalio

led = digitalio.DigitalInOut(board.GP17)
led.direction = digitalio.Direction.OUTPUT

button = digitalio.DigitalInOut(board.GP16)
button.direction = digitalio.Direction.INPUT
button.pull = digitalio.Pull.UP

while True:
    led.value = not button.value

This guide was first published on May 01, 2021. It was last updated on 2021-05-26 15:05:43 -0400.

This page (GPIO) was last updated on Dec 01, 2021.

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