Where can I find a simple DroneCAN device example?

I’d like to make device that can be configured using a few parameters and from which AP could log some data, and preferably control it using some parameters.

I have seen that currently only a handful of devices are supported DroneCAN Setup — Copter documentation

I am looking for an example on how to add something universal, like some GPIO pins that can be controlled. I understand that I would need to add some code to ardupilot side too.