Universal Region mod, 50/60 Hz switch and In-Game-Reset (IGR) for Sega Mega Drive (AKA Genesis)
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MegaDrivePlusPlus.ino Increase pad read time Nov 21, 2016
README.md Update README.md May 11, 2016



MegaDrive++ is a modchip for the Sega Mega Drive (AKA Sega Genesis). 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!
    • 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 a certain 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.
    • Can be flashed on different chips (ATtiny's, ATmega's, or even a full Arduino board), but please note that not all features are supported on all chips, depending on the number of available I/O pins, please read on for details.
    • 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.
  • Uses the popular Arduino environment, allowing for easy development, testing and modifications.
  • Last but not least, it is Open Source and Free Software!

If you are interested in modding your console with MegaDrive++, please head to the wiki. There you will find full instructions about what chip to buy, how to put MegaDrive++ on it and how to install it, with a full wiring guide for a few different Mega Drive/Genesis models that were sold.