MCP23017 I2C GPIO Expander Breakout Board – 16 Digital I/O STEMMA QT / Qwiic Compatible

Description
This MCP23017 I2C GPIO Expander Breakout Board provides an easy way to add 16 extra digital GPIO pins to your microcontroller using a simple I2C interface. It is designed for plug-and-play use and includes all required supporting components on the board, making it much more convenient than using the bare IC.

The MCP23017 works reliably with both 3.3V and 5V logic, making it compatible with a wide range of microcontrollers and single-board computers. Each GPIO pin can be configured individually as an input or output. Output pins can source or sink up to 25 mA, which is enough to directly drive LEDs, while input pins support optional internal pull-up resistors.

With three configurable address pins, up to 8 MCP23017 boards can share the same I2C bus, allowing expansion up to 128 digital GPIO pins using only two I2C wires. Two configurable interrupt pins allow the device to notify the microcontroller of input changes, eliminating the need for constant I2C polling.

This breakout follows the STEMMA QT / Qwiic standard, enabling solder-free connections and easy daisy-chaining with other compatible boards using standard cables.

Key Features

• 16 digital GPIO pins via I2C interface

• Works with 3.3V and 5V power and logic

• Each GPIO supports input or output mode

• Output drive capability up to 25 mA per pin

• Optional internal pull-up resistors for inputs

• Two configurable interrupt pins (IRQ)

• Up to 8 devices on one I2C bus (128 GPIO total)

• Digital I/O only (no analog input support)

• STEMMA QT / Qwiic compatible connectors for solder-free wiring

Interface

• Communication: I2C

• Address selection: 3 address pins (0x20–0x27)

Applications

• Expanding GPIO pins on microcontrollers

• Button and switch inputs

• LED control and indicators

• Keypads and control panels

• Robotics and automation projects

Package Includes

• 1 × MCP23017 I2C GPIO Expander Breakout Board

• 2 × 0.1-inch male header strips (soldering required)

Note
STEMMA QT / Qwiic cable is not included.