IO Expander Breakout

This breakout uses a clever Nuvoton MS51 microcontroller and some I2C magic to give you 14 additional input/output pins to connect things up to. Eight of the pins are hooked up to an Analog to Digital Converter so you can easily use analog sensors with your Raspberry Pi, as well as passive components that use an analog signal (like light dependent resistors). 

Six of the pins can be used as (up to 16-bit) PWM outputs - great for controlling devices that require a simulated analog output, like servos or non-addressable LEDs.

You can attach it to your Pi's GPIO directly or via a breadboard with the included headers, but it's also compatible with Pimoroni's fancy solderless Breakout Garden, which makes it super easy to use several different breakouts at the same time. Why not couple it with one of of Pimoroni's teeny display breakouts to show the results from all those lovely sensors?

Features

• Nuvoton MS51 microcontroller with inbuilt 12-bit ADC (datasheet)
• I2C interface, with a default address of 0x18
• Max I2C speed 400kHz
• 3.3V or 5V compatible
• Reverse polarity protection (input side only)
• Raspberry Pi-compatible pinout (pins 1, 3, 5, 7, 9)
• Compatible with all models of Raspberry Pi (Python library)
• Compatible with Raspberry Pi Pico (C++/MicroPython libraries).
• Technical Reference Manual
• Schematic

Notes

• The default I2C address is 0x18, but it's possible to change this in software if you'd like to use multiple IO Expanders, or avoid conflicts with other I2C devices.  The new address will be saved in flash memory, so will persist if unpowered.
• This board uses a Nuvoton MCU with our custom firmware but if you're brave and hackerly, you can substitute your own firmware to change the way this board works and have a super cheap and capable microcontroller (though this is not for the faint of heart!)