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Sega Master System Emulator / Sega Mark III Emulator

RetroCopy emulates the Sega Master System (SMS) at the cycle level for the 3 main components and has extremely high compatability and accuracy with this system. The SMS uses an 8bit CPU (Z80) and features 8KB of RAM and 16KB of video RAM.

The video chip can output up to 64 colors a frame at resolutions up to 256x240 (though 256x192 was most commonly used) and the audio chip can output 3 square channels and one noise channel. The SMS has the capability to output digital audio samples at pretty high quality using the square channels. Some models of the SMS came with a FM chip (YM2413) which RetroCopy will emulates if you so choose.

The SMS base systems usually had a BIOS, which RetroCopy emulates just like the real system if you choose to use one. The BIOS isn't really necessary for emulation and RetroCopy simulates the BIOS if you don't select one for the few games which use it. RetroCopy emulates all known variations of this console, including Japanese, European and North American differences.

There are numerous input devices for the SMS, RetroCopy emulates all of them allowing you to play those games which required different controllers. 3D games are also supported by halving the framerate so that you don't see both images.

RetroCopy has 100% compatibility with the Sega Master System! Every game works just like the real system!

View all games released on Sega Master System


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Mark III

The Mark III base system

The Mark III was initially released in Japan in 1985 as an answer to the Nintendo Entertainment System (NES), it was later renamed the Sega Master System when it was released in North America. Sega had previously released the SG-1000 console in 1983 but it wasn't very successful. It did however give Sega some experience in the console market and with graphics chip makers like Texas Instruments.

Texas Instruments powered many consoles and computers of the early 80s including the SG-1000, Coleco and MSX. Sega realized the graphics hardware of the last generation would need to be upgraded if it were to compete with the NES, so they went about designing a new chip based off the old one. They doubled the memory speed and went about taking advantage of this in the sprite and tile engines. They also added features like line interrupts (a relatively new effect for the time used to great effect in racing games) and increased the color range. It was also backward compatible with SG-1000 games. Sega ended up with a graphics chip which in many ways was better than the NES, however this didn't really matter in the end.


The SMS1 base system

The Famicon/NES was building a solid reputation in Japan in 1983-85 and when unleashed on North America in 1985 it reinvigorated the ailing video game market which had suffered a recession of sorts. Everyone scrambled to take advantage of this recovery in the USA market, Sega included. Sega however was late to the party and by the time the SMS was released in the Japan and the United States the Famicon/NES had already been around for at least 2 years and had a solid library of games.

Nintendo had a stranglehold on the American and Japanese markets, not only with their earlier hardware release but also with restrictive contracts they put developers under. Europe/Australia/Brazil however was relatively untouched by Nintendo. Sega took advantage of this and released its console to markets which Nintendo had not bothered with. This created an effect whereby in some regions around the world the Sega Master System was a lot more popular. Sega basically cornered a part of the market all to itself, it just wasn't as large as the USA/JAPANESE markets Nintendo dominated.


The revised SMS2 base system

Sega designed the SMS with extendability in mind hoping that its addons would be a good gimmick to get people to the system. It had a card slot, cartridge slot and expansion port which were all capable of having games put in them. The card slot was envisioned by Sega as a way to let kids bring games to school in their pocket due to the small size of the cards similar to trading cards from sports and television shows. The card slot was quickly forgotten when it didn't turn out like Sega had hoped. The expansion port was envisioned for extra hardware devices like keyboards that were only released in Japan for the Mark III. At the time having a console which could double as a computer was a big selling point.

Notable features of the SMS were the 3D Glasses, an addon which allowed games to send images to the left and right eyes simulating a 3D environment in the game. The 3D glasses plugged into the card slot, and you would then plug the 3D game into the cartridge slot. The game would send commands through the card slot to control which shutter to close or open. NVIDIA would later use similar technology on its graphics hardware.


The SMS III (released only in Brazil)

The SMS did have some technical disadvantages compared to the NES. There was no way to access the video memory except through port accesses, the end result of which reduces the amount of screen you can change each frame. The standard control pad also featured only 2 buttons and a 4 way directional controller, while the NES also had a start and select button. Some games got around this two button limitation by using the PAUSE button to act as a third in game button. The SMS is completely compatible with more advanced controllers like those found on the MegaDrive/Genesis, though no such controller was officially released for the system.

The NES also had a more sophisticated audio chip, which was capable of differential pulse-code modulation (DPCM). This meant the NES was capable of limited sample playback without it affecting the main game program greatly. The NES and SMS are both capable of also using their square channels to output digital samples but this ties up the CPU not leaving it free to do other things.

In the end, it took Sega two attempts at the console market before it could emulate the success it had in the arcade market. Whilst the SMS was a vast improvement over the earlier SG-1000 released by Sega, bad marketting and it being a reaction to the NES always meant it was going to face a tough battle. That said it can still be considered a success and it enjoys one of the most devoted fanbases to this day.



Standard Joypad




Right handed Joystick


Sports Pad


Light Phaser

3D Glasses

3D Glasses

Handle Controller

Handle Controller

SMS Cartridge


SMS Card

Sega Card

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