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This repository contains a selection of packages emulating the CircuitPython API for devices or hosts running CPython or MicroPython. Working code exists to emulate these CircuitPython packages:

  • analogio - analog input/output pins, using pin identities from board+microcontroller packages

  • bitbangio - software-driven interfaces for I2C, SPI

  • board - breakout-specific pin identities

  • busio - hardware-driven interfaces for I2C, SPI, UART

  • digitalio - digital input/output pins, using pin identities from board+microcontroller packages

  • keypad - support for scanning keys and key matrices

  • microcontroller - chip-specific pin identities

  • micropython - MicroPython-specific module

  • neopixel_write - low-level interface to NeoPixels

  • pulseio - contains classes that provide access to basic pulse IO (PWM)

  • pwmio - contains classes that provide access to basic pulse IO (PWM)

  • rainbowio - provides the colorwheel() function

  • usb_hid - act as a hid-device using usb_gadget kernel driver

For details, see the Blinka API reference.


The emulation described above is intended to provide a CircuitPython-like API for devices which are running CPython or Micropython. Since corresponding packages should be built-in to any standard CircuitPython image, they have no value on a device already running CircuitPython and would likely conflict in unhappy ways.

The test suites in the test/src folder under testing.universal are by design intended to run on either CircuitPython or CPython/Micropython+compatibility layer to prove conformance.

Installing from PyPI

On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI. To install for current user:

pip3 install Adafruit-Blinka

To install system-wide (this may be required in some cases):

sudo pip3 install Adafruit-Blinka

To install in a virtual environment in your current project:

mkdir project-name && cd project-name
python3 -m venv .env
source .env/bin/activate
pip3 install Adafruit-Blinka

Usage Example

The pin names may vary by board, so you may need to change the pin names in the code. This example runs on the Raspberry Pi boards to blink an LED connected to GPIO 18 (Pin 12):

import time
import board
import digitalio

PIN = board.D18

print("hello blinky!")

led = digitalio.DigitalInOut(PIN)
led.direction = digitalio.Direction.OUTPUT

while True:
    led.value = True
    led.value = False


Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Building locally

Sphinx documentation

Sphinx is used to build the documentation based on rST files and comments in the code. First, install dependencies (feel free to reuse the virtual environment from above):

python3 -m venv .env
source .env/bin/activate
pip install Sphinx sphinx-rtd-theme Adafruit-PlatformDetect

Now, once you have the virtual environment activated:

cd docs
sphinx-build -E -W -b html . _build/html

This will output the documentation to docs/_build/html. Open the index.html in your browser to view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to locally verify it will pass.

Table of Contents


API Reference

Indices and tables