SMS++ is a modchip for the Sega Master System gaming console. It is basically a port of my MegaDrive++ project.

Since the Master System controller only has a few buttons, it makes it impossible to perform "special combos" to control the modchip features. Thus, SMS++ requires the use of an unmodified Mega Drive/Genesis Control Pad, either 3- or 6-button.

SMS++ has the following features:

• Pause your games from the control pad: In my opinion, a huge design flaw of the Master System is the lack of a Pause button on the control pad. This forces players to stand up and run to the console to pause the game, which often leads to game playing errors. This has always scared me away from the SMS, so I had to do something to remedy: SMS++ allows you to pause your games just by pressing the Start button, as you would do on any other modern console!
• 50/60 Hz mode switching: If your console is PAL, 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!
  • 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 video mode:
    • Through the Pause/Reset button: Keep pushed to cycle through modes.
    • From the Player 1 controller pad: Press Start + B + Left for 50 Hz or Start + B + Right for 60 Hz.
  • The last used mode is saved automatically after 5 seconds and reused at power-up.
• Reset-From-Pad (AKA In-Game-Reset AKA IGR): Press Start + A + B + C.
• Make Wonder Boy in Monster Land and other games that normally don't work with the MegaDrive pad compatible with it!
• Turn the Pause button on your Master System II to a Reset button: Now that you can pause your games straight from your controller, the Pause button on the console is pretty useless. Turning it into a Reset button (which the SMS2 lacks) might make it useful again!
• Use A/B instead of B/C: Normally, when you connect a Mega Drive controller to a Master System console, you have to use B as Button 1 and C as Button 2. SMS++ follows this convention, but as this is something more I have never liked, it also allows you to map B1/B2 to A/B: Keep A pressed at power-up.
• Use A as B1+B2: This makes Double Dragon much more playable, for instance. If using A/B for B1/B2, this maps to C, of course.
• Controller autodetection at power-up:
  • When using a Master System pad, SMS++ disables all special functions, as if it just wasn't there. This also means that it should also be compatible with the Light Phaser (Though this is still untested!).
  • When using a 6-button pad, X/Y/Z map to autofire versions of A/B/C: Autofire rate is configurabile between 3 different settings (+ Off), and every button can have a different rate. Switch among them with Start + X/Y/Z.
• Supports a single or dual LED (either common-anode or common-cathode) to indicate the current mode and other settings (Colors can be set to any value when PWM pins are available).
• 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.
• 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 SMS++, please head to the wiki. There you will find full instructions about what chip to buy, how to put SMS++ on it and how to install it, with a full wiring guide for a few different Master System models that were sold.