MCP23017 - I/O Expansion for I2C BUS

MCP23017 16-Bit I/O Expander for I2C Bus

The MCP23017 is a 16-bit general purpose parallel I/O expansion device from Microchip Technology, designed for two-wire I2C bus applications. When your microcontroller or single-board computer runs out of GPIO pins, this versatile IC provides 16 additional fully configurable input/output lines using just two bus wires, making it an essential building block for Arduino, Raspberry Pi, and other embedded electronics projects.

Key Features

The device features two 8-bit ports (GPA and GPB) that can be configured independently as inputs or outputs. Each port includes an 8-bit configuration register, input register, output register, and polarity inversion register, giving you precise control over every pin. The MCP23017 supports a wide operating voltage range of 1.8V to 5.5V and high-speed I2C communication up to 1.7 MHz, ensuring seamless compatibility with both 3.3V and 5V logic systems.

Expandable Addressing and Interrupts

Three hardware address pins allow up to eight MCP23017 devices to share a single I2C bus, expanding your system to a maximum of 128 GPIO pins. Configurable interrupt-on-change features with independent programmable pull-up resistors enable efficient event-driven designs, waking your host controller only when an input changes state.

Typical Applications

This I/O expander is ideal for driving LED arrays, reading keypads and switch matrices, controlling relays, interfacing with sensors, and managing front-panel controls. It is widely used in home automation, industrial control panels, robotics, and any project where additional digital I/O is required without adding complexity to the main controller.