This page was last modified 09:07, 19 January 2020 by Gdx. Based on work by Sd snatcher and Mars2000you and others.



JoyMega is a DIY adapter that allows to connect Sega Genesis/Mega Drive game controller to MSX. By default, buttons B and C are mapped to the triggers 1 and 2 of the MSX, respectively. The adapter fully support up to 8 buttons (A,B,C, Start, Mode, X,Y,Z).

Some games are patched to use additional buttons (instead of keyboard keys for example).

If you use the loader sofaRom (See links below) by Louthrax you can set a keyboard key on each button.

This adapter is sold on Internet but can be made easily if you know a bit soldering. (See links below)

Note: A JoyMega called JoyMega2 is sold here. This version has no additional function. This is just a JoyMega made with a single gate inverter (NC7ST04) instead of the 74HCT04 (Hex inverter) that contains six gates because only one is necessary to make a JoyMega. A capacitor has also been added to avoid possible parasites. Its size is a little smaller.


  • No driver or modification need
  • Fully MSX compatible, and the extra buttons are available for use in your program
  • Compatible with the MSX-HID plug-and-play detection
  • Single mode of operation. No need to switch between "legacy" and "advanced" modes
  • Very cheap and easy to build. No translation micro-controllers are required (zero lag). Uses only classic components.
  • Also supports other devices like the Sega Multitap (MK-1654 and compatibles)
  • Low power consumption:
    • joyMega1 (74LS04 chip): from 6.6mA/33mW to 18mA/90mW, depending on the chip maker
    • joyMega1 (74HCT04 chip): 20μA/0.1mW
    • joyMega2 (NC7ST04 chip): 2μA/0.01mW


  • Does not support Sega Master System devices (they require specific adapters)
  • Does not support the Sega Menacer

JoyMegas made with a transistor are an alternative design that is problematic and result in button ghosting and glitches on many MSX models/controllers. Chose a model made with a chip instead.


DIY JoyMega adapter
JoyMega adapter by MSXCalamar
DIY JoyMega adapter
JoyMega adapter by KMTech
JoyMega adapter by RoadFighter
JoyMega adapter Rev.2 by FRS & FBLabs

Patches that allows to play with the extra buttons

Games/Software that support extra buttons