Adafruit MCP2221A Breakout - General Purpose USB to GPIO ADC I2C (Stemma QT / Qwiic)

Wouldn't it be cool to drive a tiny OLED display, read a color sensor, or even just flash some LEDs directly from your computer? Sure you can program an Arduino or Trinket to talk to these devices and your computer, but why can't your computer just talk to those devices and sensors itself? Well, now your computer can talk to devices using the Adafruit MCP2221A breakout board!

What can the MCP2221 chip do? This chip from Microchip is similar to a USB to serial converter chips but adds a GPIO and I2C interface as well. The analog/digital GPIO pins can act as 10-bit analog inputs (ADC) and there's even a 5-bit DAC output. The I2C interface is great for talking to OLEDs, sensors, PWM drivers, its the most popular interface for small devices. You can use the GPIO to do things like flash LEDs, read switches or buttons, and more. The MCP2221A breakout is like adding a little swiss army knife for serial protocols to your computer!

This chip is powerful and useful to have when you want to use Python (for example) to quickly iterate and test a device that uses I2C or general purpose digital and analog I/O. There's no firmware to deal with, so you don't have to deal with how to "send data to and from an Arduino which is then sent to and from" an electronic sensor or display or part.

This breakout has an MCP2221A chip, USB C connector, on-board 3V regulator, and a 4 pin JST SH port for I2C connectivity with 3V power and logic. This port is Stemma QT / Qwiic compatible for use with any sensor or chip that that has a matching port - you can even wire in Grove I2C devices with an adapter cable with no soldering required! See this guide for more info on Stemma QT

Check out all our Stemma QT sensors, cables, and devices you can use here.

Using this board in Python is super easy - check out our tutorial on how to get started and use our Python code to control the MCP2221A with Mac/Win/Linux and get access to our hundreds of CircuitPython libraries and tutorials.

Technical Details