I've been playing around with my MSX computer recently, and as the computer itself supports a two button joystick I wanted something that'd support more than one button. Somewhat like the Commodore 64 and Commodore Amiga, a standard Sega Mega Drive (Genesis in North America) will damage the system - so we'll need to use an adapter with it. I found a great writeup and a lot of details for building one by FRS, so I built one based on the the information provided.

As keeping with other adapters I've made, I titled it MSX Mega Drive Adapter to keep with the naming scheme (this circuit is more commonly known as a JoyMega). I've made similar adapters for other systems, one is the Atari 7800 Mega Drive Adapter as well as the C64 Mega Switcher.

Check out my github-repository for the BOM as well as a somewhat detailed description on soldering it together. Alternatively, Mark over at the YouTube-channel Mark Fixes Stuff has also created a video that goes into detail on soldering the device together, that way you don't need to spend as much time deciphering my ancient texts in order to figure out how to build it. Check it out below.