Have Commodore 64, want to use a Mega Drive/Genesis controller without breaking it?

Then you'll need some sort of adapter to make it compatible, and this is one of the solutions for doing that - inspired by the https://github.com/SukkoPera/OpenC64MegaDrivePadAdapter this does most of the same. What has been added here in addition is that you can now switch the joystick port used by the press of a button, meaning that if you switch to a game insisting on using a joystick only in port 1 instead of port 2 then you can do so without fiddling with cables. 8bitdo is coming out with new classic controllers, so you can now even play using brand new quality controllers instead of attempting to buy old ones!

Take care to read the documentation, though you can swap around so that one of the buttons is used as UP instead of the D-PAD you can't do so at the same time in order to keep your CIA chips safe. The easiest way of doing it, is only using two jumpers with the board.