Arduino-Based Modchip for Sega MegaDrive/Genesis

So, let me introduce the project I've been working on last summer:

MegaDrivePlusPlus - A modchip for the Sega Mega Drive (AKA Sega Genesis)

It's basically an evolution of the well known (well, in the retrogaming community at least...) D4s/Seb mod, taking inspiration from the SuperCIC+IGR mod available for the SuperNES.

It has the following features:

  • EUR/USA/JAP mode switching: this effectively makes your console universal, allowing it to bypass region checks and to run all games without resorting to an adapter.

  • If you come from a PAL region, you will also be able to run most games at 60 Hz, which means full-speed and full-screen! Get rid of those black bars! See the difference here: Sonic 1 - 60Hz - 50Hz comparison - YouTube!

  • The mod is switchless, so you don't need to modify the aesthetics of your console installing ugly switches, but rather you will be able to change the region:

  • Through the Reset button: Keep pushed to cycle through modes.

  • From the Player 1 controller pad: Press Start + B + Up/Down to cycle through modes or Start + Down/Left/Right to set your desired mode (according to the actual chip you have installed, more on this below).

  • The last used mode is saved automatically after 5 seconds and reused at power up.

  • Supports a single led, common-anode or common-cathode dual or RGB LEDs to indicate the current mode (Colors can be set to any value when PWM pins are available).

  • Reset-From-Pad (AKA In-Game-Reset AKA IGR): Press Start + A + B + C.

  • Supports consoles with both active-high and active-low reset signals by autosensing (i.e.: all console revisions!).

  • Uses cheap Atmel AVR microcontrollers (ATtiny's, ATmega's, or even a full Arduino board) - If flashed on an ATtinyX4(A), it is pin-to-pin compatibile with the D4s/Seb mod.

  • Even though default settings are recommended, everything can be customized to taste.

  • Last but not least, it is Open Source and Free Software!
    If you are interested in trying it out, check out GitHub - SukkoPera/MegaDrivePlusPlus: Universal Region mod, 50/60 Hz switch and In-Game-Reset (IGR) for Sega Mega Drive (AKA Genesis)