Sega Mega Drive - Its History and Many Spin-Off's

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The Sega Mega Drive / Genesis was released originally in Japan in 1988, North America in 1989, and Europe in 1990.

The first name Sega thought of for their console was the MK-1601, but Sega decided to use "Mega Drive" as the name. "Mega" had the connotation of superiority, and "Drive" had the connotation of speed and power. They went with that name for the Japanese, European, Asian, Australian and Brazilian versions of the console.

It was called the Genesis in North America, after Sega failed to gain legal rights to the brand name "Mega Drive" in that area. Rumours suggest this was due to the Pontiac car company having already manufactured a steering wheel with this name, but this theory is not officially accepted, as if true, it never came into being.

Development and Technology of the Mega Drive

The Sega Master System proved a success in South America and Europe, but it failed to ignite much interest in the North American or Japanese markets, which by the mid-to-late 80s were both dominated by Nintendo NES System which held 95% and 92% market shares respectively. Hoping to dramatically increase their share, Sega set about creating a new machine that would be at least as powerful as the then most impressive hardware on the market - the 16-bit Commodore Amiga and the Atari ST home computers.

Since the System 16 arcade games that Sega were making were very popular at the time, Hayao Nakayama, Sega's CEO decided to make their new home system a 16-bit one. This worked very well, as many of the Mega Drive's games were originally arcade games, and could be easily transferred onto a games cartridge - a system known as "Porting"


The MegaDrive had two processors - a rarity in video game consoles at the time.

Main processor: 16-bit Motorola 68000 (most commonly used). Runs at 7.61 MHz.

Secondary processor: 8-bit Zilog Z80 (or equivalent). Runs at 3.55 MHz. Was used as the main CPU in Master System compatibility mode. The Z80 was used for the sound production by many games, and therefore was a necessary component.


Made up of 5 ROMs all together -

Boot/Startup ROM - A 2KB "Trademark Security System (TMSS), Used when console started, it checks the game for certain code given to licensed developer, meaning unlicensed games without the code are locked out.

Main - 64KB

Video RAM - 64 KB

Secondary RAM - An 8KB system used when using the Master Sytem compatability mode.

Cartridge Memory area - Up to 4MB (On 32bit games - such as Sonic 3, Theme Park)


The Mega Drive has a dedicated VDP (Video Display Processor) for playfield and sprite control.

You could get up to 80 on-screen, depending on display mode. 64 × 9-bit words of color. Meaning 64 on-screen colors per frame (not including sprite/characters)


Main sound chip: Yamaha YM2612

Secondary sound chip: Texas Instruments SN76489 - Used to process the sounds when in Master System mode.


After several years hard graft - The Mega Drive was released in Japan on October 29 1988 for 21,000 Yen. It did fairly well in this area, until the Nintendo Super Famicom (otherwise known as the SNES) was released, and the appeal of Super Mario World blew the competition out of the water.

The European release was on November 30, 1990 in the United Kingdom and The Republic of Ireland, priced at £189.99.

Sega announced their North American release date for the system in 1987, becoming the second console to feature a 16-bit CPU (the first one being the Mattel Intellivision) and the first to feature single instruction 32-bit arithmetic - meaning that in certain games (such as Sonic 3) you could save your previous games. It was the first console ever to introduce such a feature, and is adored by fans to this day - Can you imagine being without your Memory Card on your PlayStation ?!

U.S. sales began on January 9, 1989 in New York City and Los Angeles with a suggested retail price of $200 USD at launch. It was released in the rest of North America on September 15 with the price reduced slightly to $190. It had a very hard time competing against the Nintendo's incredibly popular NES 8 bit console, but was still a very impressive system.

Eventually, the main competition for the Genesis became Nintendo's 16-bit SNES realesed a year after the Genesis, over which the Genesis had a head start in terms of number of games, reversing the problem Sega had faced originally against the old NES system, which was still ruling the roost.

The Genesis continued to hold on to a healthy fan base composed significantly of RPG and sports games fans. The release of Sonic the Hedgehog in 1991 began to threaten Nintendo's popularity of Mario. Sonic was released to replace former mascot Alex Kidd, and to provide the "killer app" that Sega needed. This sparked what was arguably the greatest console war in North American video gaming history.

And with the addition of the extremely popular Street Fighter series of games into the Mega Drives range - Sega developed two control pads. One with six buttons & d-pad and one with 3 buttons & d-pad. The extra three buttons were for seperate attacks, the ABC buttons being low, medium and hard punches, and the XYZ buttons being low, medium and hard punches.

Less than a year later, in 1993, Sega released a redesigned version of the console at a newly reduced price. By consolidating the internal chipset onto a smaller, unified motherboard, Sega was able to both physically reduce the system's size and bring down production costs by simplifying the assembly procedure and reducing the number of integrated circuits required for each unit.

Sega started developing an add-on feature for the Genesis, known as the 32X, and the Sega CD. It rapidly fell into obscurity, as a lack of effective advertising and disputes between Sega of America and Sega of Japan had taken their toll on the company.

By 1994, Sega's market share had dropped from 65% to 35%, and the official announcements of newer, more powerful consoles, such as the Saturn, Sony Playstation, and N64 signaled that the 16-bit era was quickly drawing to a close. Interest in the Genesis suffered greatly as a result of the new consoles, compounding its already falling sales.

In 1996, less than a year after the debut of their Saturn console, Sega quickly brought their participation in the 16-bit era to an end by discontinuing production of the Genesis and its associated accessories, including the 32x and Sega CD.

This obviously angered consumers around the world who had bought the CD and 32X attachments only to see Sega abandon all support. This can probably attribute to the decline of Sega as a console manufacturer.


There were literally hundreds of games availiable for the MegaDrive, but the most significant of them is probably Sonic the Hedgehog. Pretty much everyone has played this game at some stage, and its cult following is still around today. Other than this, there was the Mortal Kombat series, the Street Fighter series, and several others. But what Sega exceededin was creating original and unique games purely for play on the Mega Drive, such as Golden Axe, Ecco the Dolphin, and the extremely popular John Madden Football series, NBA/NHL games, and Space Harrier.


The Sega CDX

A 16-bit video game console released in 1994 to the European Market, combining the Sega Genesis and one of its add-ons, the Sega CD, into a single, compact unit as a final attempt by Sega to encourage consumer interest in its unpopular Sega CD format. Overpriced and underselling due to lack of high quality Sega CD games and the anticipation of the Genesis' successor, the Sega Saturn, it was never well supported by Sega and died a quiet death. Its counterpart, the combined Genesis/32X console, the Sega Neptune, never went beyond the prototype stage.

Wondermega (named X'eye in North America)

A combined Mega Drive and Mega-CD sold by Victor (known as JVC outside Japan)to the Japanese and North and South American Markets. It too sadly faded away.

Sega Genesis 3 (North America)

Announced in 1997 as a "budget" version of the Sega Genesis, Manufactured by Majesco. It was released in 1998 as the "Genesis 3" in North America only and originally retailed for $50, later lowered as far down as $19.99. In order to cut costs the expansion port and circuitry were omitted, thus making the Genesis 3 incompatible with the Sega CD, 32x, Power Base Converter and Virtua Racing, which lost alot of interest, and it too went away without a second thought.

The Mega-Tech and Mega Play

The Mega-Tech was an arcade machine that featured ten interchangeable Mega Drive or Master System games in an arcade cabinet, similar to Nintendo's PlayChoice-10.

First released in 1989 with some of the best titles at the time, such as Thunder Force II, Altered Beast, Tetris, Last Battle, Space Harrier II, and Golden Axe. Games could be changed at any time, and more titles, such as Sonic the Hedgehog, were made available. The games were identical to their non-arcade counterparts, and all cheat codes were functional. Games were supplied by a Japanese-shaped Mega Drive cartridge, although slightly heavier. The labels were silver and red and only had "Mega-Tech" printed on them. These cartridges are not compatible with a regular Mega Drive/Genesis due to the extra information on them stored to run the second monitor, and differences in the length of the edge connector, number of pins, pinouts, and spacing. A second, smaller nine-inch monitor is located at the top of the cabinet. It displayed instructions for each of the games. The user pays to play for a certain length of time. When time was starting to run out, the screen flashed green to notify the user that additional credits are needed should he or she want to play more of that game.

The Mega Play was another arcade system like the Mega-Tech, but this only had four cartridge slots and could not play Master System games. Cartridges were shaped like those for the Japanese Mega Drive, but incompatible with consumer Mega Drive or Mega-Tech systems.

Genesis Nomad

The original technology behind the Genesis Nomad traces back to the Mega Jet, which was a semi-portable version of the Mega Drive that was used for in-flight entertainment by Japan Airlines. The device lacked its own screen, but could play Mega Drive cartridges when hooked up to a small monitor used on Japan Airlines flights. The unit featured a directional pad on the left side and six buttons on the right, similar to the layout of a game controller.

A consumer version of Mega Jet was released by Sega of Japan on March 10, 1994 at the cost of $123 USD. It was essentially the same as the unit that was used on JAL flights, meaning that it still lacked a screen and couldn't be powered on with an AC adapter, other than the addition a mono DIN plug cord and the necessary AC adapter. No other additions or improvements were made.

Sega followed it up in October 1995 with the Genesis Nomad for the American market, essentially a Mega Jet featuring a 3.25 inch color LCD screen, a battery pack attached to the rear of the system, holding six AA batteries, making it completely portable, as opposed to simply being a small Genesis system. In addition to its other improvements over the Mega Jet, an A/V output plug was added to the top of the unit, allowing owners to play games on a television screen with a separate A/V cable. One particularly interesting feature was the ability for one player to play using a connected TV while another watched on the Nomad. The directional pad on the unit controlled all one-player games, and a port on the bottom allowed a second controller to be plugged in for two-player games. This meant that the Nomad could be a fully functional home system as well as a completely portable handheld solution with a pre-existing library of games available for it.

While the Nomad won praise for its screen resolution and features, there were some problems. The 32X and Sega CD were not compatible with the unit, and Sega's Power Base Converter, used to play Sega Master System games on the Genesis/Mega Drive, was also incompatible, also - its battery life was notoriously bad - usually only lasting 35 minutes, if you were lucky. On paper, the Nomad was the perfect color portable. It had a full color, backlit display, and supported an estimated 600 titles already on the shelves in addition to being a functional home system. But despite the price falling from $179 to $79.99, the handheld did not hold enough support to continue.

The Teradrive

A PC manufactured by IBM with an integrated Mega Drive. The system was released in Japan only. Three models were available, ranging from 148,000 to 248,000 Yen. Only the top-of-the-line model was supplied with a hard disk. A special monitor (sold separately) was available, which could display both 15 kHz RGB video signals from the Mega Drive hardware and the 31 kHz VGA output of the PC hardware, both from the VGA connector. The system also contained composite NTSC video and stereo RCA jacks for connection to a TV. Additionally, Mega Drive games could be played at the same time as the PC section is being used, and it was possible for the Mega Drive and PC hardware to interact with each other.

The Mega PC

A system produced by Amstrad under license from Sega with Mega Drive and IBM-compatible PC functionality in one. The Mega PC was similar in concept to the Teradrive, but was an unrelated project. The PC section used an Intel i386SX running at 25 MHz. It had 1 MB of RAM and a 40 MB hard disk drive. Released in Europe and Australia around 1992-1993, cream-colored, with a sliding cover on the front to change between Mega Drive and PC modes. The output from the Mega Drive section was only available through the VGA connector, to the supplied dual-sync (15 kHz/31 kHz) monitor. Though the PC section is always running when the system is switched on, Mega Drive software cannot be used at the same time as PC software, due to the system having only one video output. Could also be used with a Mega CD with the use of a special connector only available from Amstrad. Most of the Mega Drive hardware is contained on an 8-bit ISA card, with AdLib-compatible sound on the same board. The Mega Plus was an updated version of the Mega PC. It used an Intel i486 at 33 MHz and 4 MB of RAM.

Aiwa Mega CD

Probably the most unusual of any incarnation of the Mega Drive was a variant that was built around an Aiwa CD player. The unit was made up of two components - an Aiwa bookshelf-size CD radio and a dock which added the Mega Drive connections (excepting sound, which the main radio unit handled.) Oddly, Sega and Aiwa chose not to place the interface between the two on the sides that would connect, but instead opted to use a connection cable on the back. This variant of the Mega Drive is one of the rarest made, and only saw limited release into the Japanese market.

Radica Games' Legends Sega Genesis

The Sega Genesis/Mega Drive was brought back to life by the USA company Radica Games Limited under its Play TV collection. It consists of a classic Genesis joypad with a video cable ready for plugging into a television to play a variety of games. Some models actually condense the Genesis/Mega Drive system onto a single chip, allowing a cartridge slot to be added. At the current moment six versions of the gadget exist:

* Play TV Legends Sega Genesis, with the games Sonic 1, Altered Beast, Golden Axe, Kid Chameleon, Dr. Robotnik's Mean Bean Machine, and Flicky.

* Play TV Legends Sega Genesis Volume 2, with the games Sonic 2, Echo the Dolphin, Gain Ground, The Ooze, Columns, Alex Kid & the Enchanted Castle.

* Play TV Legends Street Fighter 2, a pack of two 6-button pads with Street fighter II and Ghouls&Ghosts.

* Play TV Legends Menacer, a collection of light gun games from the Menacer 6-in-1 cartridge, including Pest Control, Space Station Defender, Whack Ball, Front Line, Rockman's Zone, and Ready, Aim Tomatoes.

* Play TV Legends Outrun 2019, a racing wheel with the game included.

* Play TV Legends Super Sonic Gold, a collection of Sonic games, including Sonic the Hedgehog, Sonic the Hedgehog II, Sonic Spinball and Dr. Robotnik's Mean Bean Machine.

Currently Sega has no console in the pipeline, but is succeedingly very well in both the arcade market and games manufacturing - making several games, including the popular Sonic Heroes series, and the new game Shadow the Hedgehog for Microsoft's X-Box console.

The Mega Drive sold over 35 million units worldwide.

Its most popular gamewas Sonic the Hedgehog 2.

It is legendary.

Hats off to you Sega Mega Drive !

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