How compatible is the Xiao to an Arduino e.g. Nano?

Thanks for looking deeper into the operations.
How would I verify an interrupt is recognized? That is something I haven’t had to deal with before.

This is a sample of a data stream on pin 2:

Note that might not be triggered at the start of a packet.
This is description of a packet: https://dccwiki.com/Digital_Packet

The data is determined by the period of the square wave 58uS = 1, 100uS = 0

Cheers