Happy New Year,
So I've been playing with the C64 a little trying to learn how to program a little and I set myself a little project to attach my uIEC SD card drive to the 64 core.
It works pretty well, but I can't work out how to get the internal 1541 and the external IEC to work at the same time, they sort of freeze each other out. So I used Switch(0) on the nano board to switch between them. It works on the fly so no need to restart the core.
The source is here if you want to have your own play with it and if you own a uIEC adapter or a SD2IEC adapter (my uIEC uses the same firmware).
You do need to build an adapter board though . . . breadboard layout is also in the github repo.https://github.com/mtfong/C64_MiSTer
I used some spare Arduino pins as well so as not to impinge on the real core, although if you have an I/O board getting the 3.3V and 5V pins may be hard.
I also got a patch called JAFFY DOS to add some functionality to the C64 kernal for some SD2IEC hotkeys as well.
Lastly if you work out how to get them both to work together any help would be appreciated.