Originally written by Paul Qureshi
 Modifications in this repository by Denilson Sá <>

My changes on top of RetroAdapter to make it work with my microcontroller. This
is basically the RetroAdapter version 2.1a with some tweaks in the Makefile, an
updated usbdrv, and many modules disabled.

For a long while I wanted to build a Sega Mega Drive controller adapter to USB.
Fortunately, Paul Qureshi wrote have created RetroAdapter and published all the
source and schematics on his website <>.
This adapter uses an ATmega 8-bit microcontroller with almost no extra
components (only a few resistors, a few capacitors, a couple of Zener diodes, a

He used ATmega168, which is more powerful than the ATmega8 that I already have.
In order to make it compile and make it fit in 8KB (or 6KB + bootloader), I had
to make small changes to the RetroAdapter code. These changes are saved in this

The Makefile changes mostly come from my previous project:

My blog post about this project: