Introduction

Drivers for various I2C GPIO expanders. The library does not require any libraries other than the standard install of circuit python. Once the exapander has been initialized, the pins can be defined and interacted with in the same way as GPIOs on the CPU.

This library currently supports

• PCA9555
• PCAL9555
• PCA9554
• PCAL9554
• PCA9538
• PCAL9538

Other expanders will likely be added over time as I use them.

Based on Adafruit's library for the MCP230xx expanders

Dependencies

This driver depends on:

• Adafruit CircuitPython
• Bus Device

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle or individual libraries can be installed using circup.

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 circuitpython-i2c-expanders

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

sudo pip3 install circuitpython-i2c-expanders

To install in a virtual environment in your current project:

mkdir project-name && cd project-name
python3 -m venv .venv
source .env/bin/activate
pip3 install circuitpython-i2c-expanders

Installing to a Connected CircuitPython Device with Circup

Make sure that you have circup installed in your Python environment. Install it with the following command if necessary:

pip3 install circup

With circup installed and your CircuitPython device connected use the following command to install:

circup install i2c_expanders

Or the following command to update an existing version:

circup update

Usage Example

Take a look in the examples folder for a basic example of using this library.

Documentation

API documentation for this library can be found on Read the Docs.

For information on building library documentation, please check out this guide.

Contributing

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