Adafruit MCP23017 I2C GPIO Expander Breakout
We have ✅ 8 available of the AF-5346 in our Sydney warehouse. An extra 77 units available with a short lead time.
The Adafruit MCP23017 I2C GPIO Expander Breakout adds 16 extra GPIO pins to any microcontroller or microcomputer over I2C. Each pin can be configured as a digital output (driving up to 25 mA — perfect for LEDs) or as an input with optional internal pull-up resistors.
With three configurable address pins, you can connect up to 8 boards on a single I2C bus for a total of 128 GPIO. Two configurable interrupt (IRQ) pins let you monitor input changes without polling the bus. The MCP23017 runs on both 3.3V and 5V power and logic, making it compatible with virtually any development board.
Key Features
- 16 GPIO Pins – Each configurable as input (with optional pull-up) or output (up to 25 mA per pin)
- I2C Interface – Simple two-wire communication with 3 address pins for up to 8 devices per bus
- Dual Interrupt Pins – Configurable IRQ outputs eliminate the need for bus polling
- 3.3V and 5V Compatible – Works with any logic level without additional shifting
- STEMMA QT / Qwiic Ports – Solderless I2C daisy-chaining on both sides of the board
- Matching Ground Pads – Convenient ground connections alongside each GPIO pin
- Breadboard Friendly – Includes header strips for breadboard prototyping
Ideal For
- Projects requiring more GPIO than your microcontroller provides
- LED matrix or button matrix control
- Input expansion for keypads, switches, and sensors
- Daisy-chaining multiple expanders for large-scale I/O
Package Contents
- 1× Adafruit MCP23017 I2C GPIO Expander Breakout (with STEMMA QT / Qwiic connectors)
- 2× Header pin strips
Resources
The Adafruit MCP23017 I2C GPIO Expander Breakout appears in the following collections:
