IO Pi Plus

The IO Pi Plus is a 32-channel GPIO expander designed for use with the Raspberry Pi. This development board is built around the MCP23017 16-bit I/O expander from Microchip Technology Inc. It features two MCP23017 chips, enabling the Raspberry Pi to interface with up to 32 digital inputs or outputs. The IO Pi Plus is powered directly from the Raspberry Pi via the GPIO port, and its extended pins allow it to be stacked with other expansion boards.

The I²C address is configurable using on-board solder jumpers. Each MCP23017 supports up to 8 unique I²C addresses, and since there are two MCP23017 chips per IO Pi Plus, up to four boards can be stacked on a single Raspberry Pi, offering a total of 128 I/O pins.

The board also features a 5V power input, which can be isolated from the Raspberry Pi using a solder jumper labeled “Link” on the PCB. This allows you to connect a separate high-current power supply, reducing the power burden on the Raspberry Pi. An external supply is recommended when connecting multiple IO Pi Plus boards. The 5V input is compatible with standard 5mm screw terminals.

To use the IO Pi Plus independently from the Raspberry Pi, connect the following GPIO header pins:

• 3.3V (Pin 1)

• SDA (Pin 3)

• SCL (Pin 5)

• Ground (Pin 6)

If you are not using an external 5V power supply, you must also connect the 5V pin.

Features

•  32 GPIO pins
• Control via the Raspberry Pi I2C port
• Open Source Python, MicroPython, Home Assistant, C, C++, Node.js and .Net Core software libraries
• Stack up to 4 IO Pi Plus boards on a single Raspberry Pi
• Solder jumper selectable I2C addresses
• External 5V Input with an isolation solder jumper
• Built around the MCP23017 from Microchip Technologies Inc
• Configurable interrupt output pins - Configurable as active-high, active-low or open-drain
• Polarity Inversion register to configure the polarity of the input port data

If you have any questions about how to use the IO Pi Plus you can browse through our Frequently Asked Questions.

Our Knowledge Base has step-by-step guides that will guide you through setting up and using your IO Pi Plus.

We also have a Support Forum where you can post questions and find answers.

The IO Pi Plus is supplied with the 40-pin GPIO connector unsoldered. Before using the IO Pi Plus, you need to solder the connector onto the PCB. The power link and I2C address selection are configured using solder jumpers. For convenience, we supply the IO Pi Plus with the power link jumper and one address selection jumper pre-soldered.

The I/O input pads are spaced 2.54mm apart. You can solder wires directly to the board or use 2.54mm pitch headers. The IO Pi Plus is compatible with 20-pin IDC vertical and right-angle headers allowing you to use ribbon cables to connect your external devices to the board.

To install the IO Pi, press the 40-pin connector down onto the Raspberry Pi GPIO pins with the board sitting over the top of the Raspberry Pi.

When installing more than one IO Pi on a single Raspberry Pi board, you must configure the address select jumpers for each IO Pi.

Remove the isolation jumper when connecting an external power supply to the 5V port.

Watch our assembly guide on YouTube. (opens in a new window)

PCB Header Assembly Jig

Download and print our PCB Header Assembly Jig to hold your circuit board when soldering the header pins.

Microchip MCP23017

This expansion board has Python, MicroPython, C, C++, Node.JS, .Net Core, Arduino and Home Assistant libraries available to get you started with your next project. All of our software libraries are open source and can be download from our GitHub repository or by clicking on the logos below for your selected programming language.