Adafruit TCA8418 Keypad Matrix and GPIO Expander Breakout - STEMMA QT / Qwiic

The Adafruit TCA8418 is a versatile and powerful I2C GPIO expander and keypad matrix driver. Featuring 18 total I/O pins arranged as 10 columns and 8 rows, it supports up to 80 buttons in a matrix configuration, or can be used as individual GPIO inputs or outputs.

This chip includes a 10-element event queue for key press and release events, and provides interrupt output on the INT pin. It supports features such as pull-ups, debounce filtering, and fast 1-MHz I2C communication, making it an ideal multi-tool for handling keypads, buttons, or LEDs in your microcontroller projects.

The breakout is designed in the STEMMA QT / Qwiic form factor for easy plug-and-play compatibility with other devices and cables. It includes a built-in 3.3V regulator and level shifting allowing use with both 3V and 5V microcontrollers.

• Supports 80 buttons using 18 GPIO pins
• 10-column by 8-row keypad matrix support
• 10-byte FIFO key event queue stores key presses/releases
• Low standby current (3 µA)
• Open-drain active-low interrupt output
• Built-in debounce filter with 50 µs debounce time
• Compatible with Arduino and CircuitPython libraries
• STEMMA QT / Qwiic compatible connectors for easy connection
• Dimensions: 35.5mm x 17.7mm x 4.6mm
• Weight: 2.5g

Note: JST connector may be off-white or black.

There are two informative videos available demonstrating the breakout and its applications.