RetroRGB - 02 Oct 2026
MattKC recently posted a video that's about how he made a Genesis to CDi controller adapter...but it's actually a lot more than that. Matt goes over how these controllers work, starting with the origin of the connector, the Atari 2600. Matt's overview of how that works, how the Genesis 3-button controller adapted to it and how the Genesis 6 button controller made compatibility with the existing connectors possible, was absolutely excellent on its own. Then Matt broke down how the CDi controller worked and how he made an open source adapter for it. Definitely check out the video, with some more thoughts below the links:
Github link to adapter: https://github.com/itsmattkc/gencdi
Support Matt: https://www.patreon.com/mattkc
I honestly can't recommend this video enough to my fellow nerds. Obviously, anything with the Philips CDi interests me out of morbid curiosity, but anyone who's ever been curious about how controllers work will love it. I also liked that Matt made the point that these "adapters" cycle through button changes multiple times per frame, which is why they can be made with little to no lag. Although I'm always curious if that "lag" would ever play a factor in actual gameplay - Other than the incompatibilities Matt mentioned in the video. Maybe I'll have to run that analysis one day, just to prove out how much "lag" the Genesis 6-button controller adds over the 3-button. Although I'm pretty sure the answer is "zero"...
Also, I just love how a fellow nerd already took Matt's design and evolved it into their own. Stuff like this is great, but even better when the community embraces the open source nature and takes it even further!
Original: https://retrorgb.com/mattkcs-genesis-cdi-controller-overview.html