I have something prepared to bring the 2 button hack to the next level

[kramlat0]

I am working on a module that you connect to the controller ports of your VCS and you connect your sega genesis / megadrive controllers on the other side. It sends the pin 7 signal pulse to the controllers, allowing cleverly crafted code to extract A and Start (and if you know what you are doing, X, Y, Z, and Mode) in addition to the B and C the 2 button hack allows. It does not replace the 2 button hack, but extends it (with my board, you must hold down A and B to enable the old hack when you turn it on.

At the moment,  have already make a schematic which will be posted as a png and a 3d render of what the board would look like as a png which will be attached to this forum post. If you want the easyeda files, I will provide them free of charge so we can make this real.

the ten pin headers are for connecting cables for connecting to a VCS or other old computer. i.e. a C64

I had it pull up pin 5 so it can be easily detected by software. I am working on driver code at the moment.

Edited March 21 by kramlat0
forgot to mention something

[kramlat0]

I made it pull up on pin 5 so it can be detected easily. atm, I am busy writing driver code.

[+Karl G]

I think what you are trying to make already exists, unless I am misunderstanding something. I don't think any 2600 games have been made to take advantage of it, though:

 

https://stoneagegamer.com/mega7800-controller-adapter-for-atari-7800-retrohq.html