Technically all of these protocols are bit-banging once you get low enough in the stack -- it's just that the PIO is particularly well tuned for arbitrary proto

Technically all of these protocols are bit-banging once you get low enough in the stack -- it's just that the PIO is particularly well tuned for arbitrary protocol implementation. FWIW, I believe there is a real bit-banged ethernet stack on Atmel. https://hackaday.com/2014/08/29/bit-banging-ethernet-on-an-attiny85/ https://hackaday.com/2014/08/29/bit-banging-ethernet-on-an-a...