Adafruit MCP2221A Breakout - General Purpose USB to GPIO ADC I2C

by Adafruit

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 the 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

12 customer reviews

2 years ago
That’s a fantastic little devil! Just in a minute we can convert an image using Python on a computer and show it on I2C display and much more. Don’t need to use a silly Thonny MicroPython editor and wait to upload the code to a microcontroller every time.
by Aleksei about Adafruit MCP2221A Breakout - General Purpose USB to GPIO ADC I2C via REVIEWS.io
3 years ago
The Adafruit MCP2221A breakout fulfils my expectations completely! I bought it to create an easy interface between a desktop PC running Microsoft Flight Simulator 2020. The goal of the project in which I am using the MCP2221A breakout is to receive, filter and display the track flown by aircraft in use in the flight simulator. Data from the flight simulator is sent via a COM port of a PC running MS Windows (10 or 11). The data is fed to the USB-C input of the MCP2221A breakout. The output of the MCP2221A breakout, through its StemmaQT/qwiic connector, is fed to the StemmaQT/qwiic input of a Pimoroni i75 hub controller (PIM 584). On the MCP2221A I had to make 2 wire connections to let the MCP2221A convert USB-UART-to-I2C: Pin TX to Pin SCL and Pin RX to pin SDA (see the images). I also connected an external LED with a series resistor of 330 ohm between the MCP2221A breakout 5V pin and the SCL pin. This I did to let the LED indicate when GPS data has arrived. In the i7 hub controller I have running a micropython script that handles the received data. I added an Adafruit ISO154x optical I2C isolator between the MCP2221A breakout and the i75 hub controller. This was just a simple connect in series of the optical isolator that has two StemmaQT/qwiic connectors. This project is now running satisfactory. See the three images added. ToDo: create a repository on Github about this project. Check at: www.github.com/PaulskPt.
by Paulus about Adafruit MCP2221A Breakout - General Purpose USB to GPIO ADC I2C via REVIEWS.io
4 years ago
Great product brings USB-Serial conversion into the USB-C era and adds some bells and whistles. Works in Windows 10 out of the box as a FTDI style USB-Serial. Also well supported in Python with a custom HID interface for I2C, GPIO and a low-end ADC (although in most cases probably to connect a better chip over I2C).
by John about Adafruit MCP2221A Breakout - General Purpose USB to GPIO ADC I2C via REVIEWS.io

6 user photos