What is it?

Onion Feather to Adafruit Feather with Qwiic and isolated SPI bus using a tri-state buffer.

Why did you make it?

I have made a huge commitment to featherwings and the Adafruit Feather form factor, I wanted to be able to use those featherwings with the Onion. I use the featherwing form factor for my energy monitor demonstrators including the ATM90E26 Featherwing and ATM90E36 Featherwing

What makes it special?

This board converts the Onion with its 2mm pin pitch into a breadboard friendly feather and allows usage with most Adafruit Featherwings. It is possibly the only feather offering Linux, USB-host, Wifi and Ethernet without any extra wings.

I have personally tested it with the Adafruit OLED Featherwing over I2C, other I2C devices should work as well. The board also includes a native 2 channel ADC attached to the Analog pins of the feather. Please see the Github repository for details on features.

The board also feature battery backup and a boost converter allowing usage on batteries with some USB peripherals plugged in. I have tested it with USB-storage devices and they are identified correctly by the Linux kernel on the Onion.