GTR V1.0 BIGTREETECH direct connection with Pi and Octo

Working on a new printer with GTR V1.0 BIGTREETECH and M5 board. Would like to connect Pi and GTR directly, so here´s my questions:

Did anyone already use this combination? What´s your experiences in it?

Which pins to connect at least? Don´t wanna block the full range of Pi pins.

What port or other settings to be done in Octoprint to make use of this connection in stead of standard USB-Port?

What did you already try to solve it?

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, what kind of hardware precisely, ...)

So you don't need to use many pins, go to the github and they have a pinout at the bigtreetech/gtr subdirectory with every pin numbered and mildly explained. I haven't managed to make it do exactly what I want yet, but I'm getting there. It is a very powerful, nearly supportless board. Contact me at for specific assistance, I probably won't check this post again.