The MSX Mega Adapter project provides a DIY solution for MSX users who want to use Sega Mega Drive/Genesis gamepads with MSX computer systems. The project provides detailed instructions for building the adapter using off-the-shelf components, and it is designed to be compatible with a wide range of MSX computer models.
The adapter connects to the MSX joystick port, and it allows users to connect a Mega Drive/Genesis gamepad to the computer and use two buttons in MSX games. The adapter includes a microcontroller that handles the translation of the gamepad input to the corresponding MSX joystick input.
The project is based on the original Joy Mega and first designed by FRS, and it is currently available on GitHub at https://github.com/tebl/MSX-Mega-Adapter/
I decided to build one of those so I can use my Bluetooth game pads with the 8bitdo Mega Drive to Bluetooth adapter on my MSX computers. This article documents the bill of materials as well as offers a few tips if you decide to build one of those.
Bill of Materials
| Reference | Value | Description | Qtd | Link |
| C1 | 100nF | DIP ceramic capacitor (104) | 1 | Ali Express |
| D1,D2 | 1n5711 | DIP diode (DO-35) | 2 | Ali Express |
| J1 | DB9 Female | Female DB9 right-angle connector | 1 | Ali Express |
| J2 | DB9 Male | Male DB9 right-angle connector | 1 | Ali Express |
| U1 | DIP14 | DIP14 Socket | 1 | Ali Express |
| U1 | 74HCT04 | Hex Inverter | 1 | Ali Express |
Building the Adapter
Assembling the adapter is relatively simple. First, orient the diodes correctly and solder them onto the board, ensuring that the stripes on the board align with those on the diodes. Next, install the resistors and capacitors, and then add the DIP socket. It’s important to align the first pin with the silkscreen marking on the board.
When installing the large DB9 connectors, make sure to use the male connector on the Sega Mega Drive side and the female connector on the MSX side.
Tests
Initial test can be done using the MSX HIDTEST or just playing games that use the two buttons. Examples are Space Manbow, R-Type, etc. In my case, the M30 assumed buttons B and C as active for the MSX. The A button became inactive on the game pad.
Case
I found a case for the JoyMega that fitted ok with this variant. It is available on Thigiverse at Joymega Enclosure Mk.II by jducreux – Thingiverse