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Sega Mega Drive / Sega Genesis
Mega Drive Logo (Europe & Australasia)
Mega Drive Logo (Europe & Australasia)

Genesis Logo (North America)
Genesis Logo (North America)
Sega Mega Drive, European/Australasian (PAL) version.
ManufacturerSega
TypeVideo game console
GenerationFourth generation era
Units soldWorldwide: 29 million[1] [2]
United States: 15.4 million[3] [4]
Brazil: 2 million[5]
MediaCartridge
CPUMotorola 68000
Online servicesSega Meganet, Sega Channel, XBAND
Best-selling gameSonic the Hedgehog 2, 6 million (as of June 2006)[6]
PredecessorSega Master System
SuccessorSega Saturn

The Sega Mega Drive (メガドライブ, Mega Doraibu) is a 16-bit video game console released by Sega in Japan in 1988, North America in 1994, and the PAL region in 1990. It was sold under the name Sega Genesis in North America as Sega was unable to secure legal rights to the Mega Drive name in that region.

The Mega Drive was the successor to the Sega Master System and was Sega's third home console and second to be sold outside of Japan.

The Mega Drive is part of the fourth generation era of consoles, and the first of its generation to achieve notable market share in Europe and North America. It was a direct competitor of the TurboGrafx-16 (which was released one year earlier) and the Super Nintendo Entertainment System (SNES) (which was released two years later). The Sega Mega Drive began production in Japan in 1988 and ended with the last new game being released in 2002 in Brazil.

History

Although the Sega Master System had proved a success in Brazil and Europe, it failed to ignite much interest in the North American or Japanese markets, which, by the mid-to-late 1980s, were both dominated by Nintendo's large market shares.[7] [8] Meanwhile in the arcades, the Sega System 16 had become a success. Hayao Nakayama, Sega's CEO at the time, decided to make its new home system utilize a similar 16-bit architecture.[9] The final design was eventually also used in the Mega-Tech, Mega-Play and System-C arcade machines. Any game made for the Mega Drive hardware could easily be ported to these systems.[10]

The first name Sega considered for its console was the MK-1601, but it ultimately decided to call it the "Sega Mega Drive". The name was said to represent superiority and speed, with the powerful Motorola 68000 processor in mind.[11] Sega used the name Mega Drive for the Japanese, European, Asian, Australian and Brazilian versions of the console. The North American version went by the name "Genesis" due to a trademark dispute,[12] while the South Korean versions were called Super Gam*Boy (수퍼겜보이) and Super Aladdin Boy (transliterated from 수퍼알라딘보이; this was the Korean version of the Mega Drive 2).

Launch

The Mega Drive was released in Japan on October 29 1988 for ¥21,000,[13] almost exactly a year after the NEC PC Engine. Although this initially caused slow sales, the Mega Drive soon eclipsed the earlier machine in popularity and sales.[14]

North America

File:SegaGenesis-USALaunchAd.jpg
First Sega Genesis Print Ad [15]

In 1987, Sega announced a North American release date for the system (under the name of Sega Genesis) of January 9 1989,[16] making it 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. Sega was not able to meet the initial release date and U.S. sales began on August 14, 1989 in New York City and Los Angeles[17] with a suggested retail price of US$200 at launch. The Genesis was released in the rest of North America on September 15 of the same year with the price reduced slightly to $189.99.

Europe

The European release was on 30 November 1990. In the United Kingdom and Republic of Ireland it was priced at £189.99. The first UK shipment of 30,000 units was sold at retailers Comet, Dixons, Rumbelows and Toys "R" Us.[18]

Following on from the European success of the Sega Master System, the Mega Drive became a very popular console in Europe.[19] Unlike in other regions where the NES had been the dominant platform, the Sega Master System was the most popular console in Europe at the time.[20] In the United Kingdom the most well known of Sega's advertising slogans was "To be this good takes AGES, to be this good takes SEGA". Some of these adverts employed adult humour and innuendo with sentences like "The more you play with it, the harder it gets" displayed with an illustration of the waggling of a joystick.[21] A prominent figure in the European marketing was the "Sega Pirate". This character was a talking one-eyed skull that starred in many TV adverts with a generally aggressive and humorous attitude.

The relatively late release of the Mega Drive in Europe assured a strong launch line-up in comparison with other regions. The ports of arcade titles like Altered Beast, Golden Axe and Ghouls 'n Ghosts, available in stores at launch, provided a strong image of the console's power to deliver an arcade-like experience (even though these games were not identical to the arcade versions) when compared to other home conversions of these games.[22] The arrival of Sonic the Hedgehog in 1991 was just as successful as in North America, with the new Sega mascot becoming popular throughout the continent.[22]

Brazil

The Mega Drive was released by Tec Toy in 1990, only a year after the Brazilian release of the Sega Master System.

Tec Toy also ran the Internet service Mega Net, and produced some games exclusively for Brazil—including a port of Duke Nukem 3D.[23] As of September 2006, the Mega Drive is still manufactured in Brazil, with games built into the console.[24]

On December 5 2007, Tec Toy released a portable version of Mega Drive with 20 built-in games.[25] [26]

Console wars

Main article: Console wars

The Sega Mega Drive initially competed against the aging 8-bit NES, over which it had superior graphics and sound. Nonetheless, it had a hard time overcoming Nintendo's ubiquitous presence in the consumer's home. Sega forced the theoretically competitive TurboGrafx-16 system into relative obscurity, thanks in part to NEC's poor North American marketing campaign.[27] However, after the release of the PC-Engine CD add-on and the Nintendo Super Famicom, the Mega Drive soon lost ground in the US market.

In an attempt to build itself a significant consumer base, Sega decided to focus on slightly older buyers, especially young men in their late teens and early 20s who would have more disposable income and who were eager for more "grown-up" titles with more mature content and/or more in-depth game play.[28]

File:SegaGenesis-NintendontAd.jpg
Sega advertisement for "Genesis does what Nintendon't" campaign featuring After Burner II and Super Monaco GP

One of Sega's most famous advertisements in North American media was its slogan "Genesis does what Nintendon't",[29] [15] which showcased the graphics advantage that the Genesis held against the aging NES.

To compete with the release of the SNES in the US, Sega promoted the console with "Blast Processing", a term invented to suggest that the Mega Drive was capable of handling games with faster motion than the SNES. Eventually, Nintendo's 16-bit SNES became the Mega Drive's main rival, though the Mega Drive had a head start in terms of user base and number of games, reversing the problem Sega had faced against the NES. The Mega Drive continued to hold on to a healthy fan base, being still the most popular console together with the SNES in 1995.[30] The release of Sonic the Hedgehog in 1991 began to threaten Nintendo's stranglehold on the US console market. Sonic was released to replace former mascot Alex Kidd, and to provide the "killer app" that Sega needed.[13]

File:Sega Pirate.png
The Sega Pirate, a popular marketing icon for the console in Europe

The console did not have a major competitor in Europe until the launch of the SNES in 1992. But unlike in North America, Nintendo's 16-bit console did not outsell the Mega Drive, which enjoyed a strong position until withdrawing from the 16-bit market. In the United States, the Mega Drive sold 13 million units in five years.[31]

32-bit era and beyond

After the release of the Mega-CD (Sega CD in North America) and 32X add-ons for the Mega Drive, Sega's last big announcement came in the form of a partnership with Time Warner in the U.S. to offer a subscription-based service called Sega Channel that would allow subscribers to "download" games on a month-by-month basis.

The poor performances of the Mega-CD and 32X, a lack of effective advertising, and disputes between Sega of America and Sega of Japan took their toll on the company.[32] By mid 1994, Sega's market share had dropped from 65% to 35%,[32] and the official announcements of newer, more powerful consoles, such as the Sega Saturn, PlayStation, and Nintendo 64 signaled that the 16-bit era was drawing to a close.

In 1997, Sega licensed the Mega Drive to Majesco so that they could re-release the console.[33] Majesco began re-selling millions of formerly unsold cartridges at a budget price together with the second model of the Genesis, until they later released a third version of it. The last commercially licensed release in North America was Frogger, released in 1998.[34]

The Mega Drive was supported until 1998 in Europe, when Sega announced they were dropping support for it.[13] It was discontinued along with its predecessor, the successful and long-lived Sega Master System, to allow Sega to concentrate on their newer console, the Saturn. The Mega Drive's add-ons, the Mega CD and 32x, were also both discontinued at this point, having been the same general failures they were in the other regions. In the UK the last stocks of the Mega Drive II were sold by the end of 1999.

On May 22, 2006, Super Fighter Team released Beggar Prince, a game translated from a 1996 Taiwanese original. It is the first commercial Sega Mega Drive game since 1998 in the North American market. It was also released worldwide.[35]

Emulation

In recent years, there has been some revival of interest in the Mega Drive, led largely by the grey market trade in both unlicensed cartridges and dumped ROMs, which are played through emulators such as Kega Fusion, GENS, or Genecyst. There is also a trend towards home programming, using the PC-based SGCC.

In 2004, there came a trend toward plug-and-play TV games, and Radica Games released licensed, self-contained versions of the Sega Mega Drive in both North America (as the Play TV Legends Sega Genesis)[36] and Europe (as the Sega Mega Drive 6-in-1 Plug 'n' Play), which contain six popular games in a small control box, with a permanently connected control pad. It does not have a cartridge slot, and thus is a dedicated console.[37]

The GameTap subscription gaming service includes a Mega Drive emulator, and has several dozen licensed Mega Drive games in its catalog.[38]

The Console Classix subscription gaming service also includes an emulator, and has several hundred Mega Drive games in its catalog.

In 2006 a compilation of 28 Genesis/Mega Drive games, called Sega Genesis Collection, was released for the PlayStation 2 and PlayStation Portable. During his keynote speech at the 2006 Game Developers Conference, Nintendo president Satoru Iwata announced that Sega will make a number of Genesis/Mega Drive titles available to download on the Wii's Virtual Console. These games are now available along with other systems' titles under the Wii's Virtual Console.[39] The 16-bit Sega selections available on the Virtual Console at launch were Altered Beast and Sonic The Hedgehog. Each title costs 800 Wii Points (US$8) except in Japan, where they are 600 Points (¥600). There are also selected Mega Drive titles on the Xbox 360, Such as Sonic The Hedgehog, and Sonic 2, where they are both 400 MS Points.

At Tokyo Game Show on September 21 2006, Ken Kutaragi, President and CEO of Sony Computer Entertainment, announced that Sega Mega Drive game ports would be available on the PlayStation Network (network service for the Playstation 3).[40] No specific titles or price points have been confirmed as of yet, with Kutagari simply stating that these specifics will be discussed with individual publishers. This, however, was later contradicted by SEGA Japan when a short statement was issued stating "that such claims are not correct at this point".[41]

Master System compatibility

Sega Power Base Converter

One of the key design features of the console is its backwards compatibility with Sega's previous console, the Sega Master System. The 16-bit design was based upon the 8-bit design, albeit enhanced and extended in many areas. In order to achieve backwards compatibility, the Master System's central processor and sound chip (the Zilog Z80 and SN76489 respectively) were included in the Mega Drive, and the Mega Drive's Video Display Processor (VDP) was capable of the Master System's VDP's mode 4 (though it cannot run in modes 0, 1, 2, or 3).

As the cartridge slot was of a different shape, Sega released the Power Base Converter, a separate device that sits between a Master System cartridge and the Mega Drive's cartridge slot. The Power Base Converter does not contain any SMS components, instead functioning as a pass-through device. The converter contains a top slot for cartridge-based games along with a front slot for card-based games, as well as the 3-D glasses adapter. When a Master System game is inserted, the system puts the Z80 in control, leaving the Mega Drive's main 68000 processor idle.

Both 2-button Master System pads and standard Mega Drive pads can be used to play Master System games, although due to slight differences in how the pads operate, some Master System games inadvertently cause the wrong set of inputs to be selected in a Mega Drive pad, preventing input from working correctly and necessitating the use of a Master System controller. The "pause" function, as with on the Master System itself, is not available from the controller but is accessed by a button on the Power Base Converter.

In Japan the device is known as the "Mega Adapter". The PAL variant is called the "Master System Converter" in mainland Europe.[42]

The Power Base Converter is not fully compatible with the redesigned Mega Drive 2. A second version, the "Master System Converter II", was released to address this problem. This second version adapter was produced in far fewer quantities and only released in Europe.

The only game which does not work with this device is F-16 Fighting Falcon.[43]

Peripherals

An original 3 button controller with Genesis logo.

Controllers

The standard Mega Drive controller features three main buttons and a "start" button usually used for pausing mid-game. The controller itself had a distinctive rounded shape. Sega later released a six-button version which was slightly smaller and featured, as well as three more face buttons, a "mode" button to allow the controller to work with certain older games which it would otherwise be incompatible with. An infra-red wireless version of the six-button controller was also released.

Mega-CD

Main article: Sega Mega-CD

The Sega Mega-CD became available in 1991, 1992 and 1993 in Japan, North America[44] and Europe [45]respectively. It plugs into the side of the Mega Drive and provides access to CD games as well as allowing the user to play music CDs and CD+Gs.

Original three button joypad with later six button version

32X

Main article: Sega 32X

The Sega 32X allows the user to play technically superior 32-bit games on the Mega Drive. It was released in 1994 in Japan and North America and 1995 in Europe. The 32X plugs into the Mega Drive's cartridge slot and the game cartridges are then plugged into the 32X.

Other

A number of other peripherals for the Mega Drive were released that added extra functionality. The Menacer Light Gun was developed in response to the Super Scope for the SNES and was only compatible with the Menacer 6-game cartridge and a few other games. The Sega Mouse and Sega Mega Mouse were also released for the Mega Drive, the latter being available in North America while the other served the Japanese and European markets. A foam-covered bat called the BatterUP and the TeeVGolf golf club were both released for the Mega Drive and SNES and provided support for similar games.[46][47] As well the official Mega Drive peripherals, the console was also compatible with Sega Master System accessories through use of the Power Base Converter.[48][13]

Both Electronic Arts and Sega released multi-taps for the system to allow more than the standard two players to play at once. Initially, EA's version, the 4-Play, and Sega's adapter, the Team Player, only supported each publisher's own titles. Later games were created to work on both adapters. Codemasters also developed the J-Cart system, providing two extra ports with no extra hardware, although the technology came late in the consoles life and only featured on a few games.

The Megamodem, a modem with a speed of 1,600 to 2,400 bit/s, could be connected to the DE-9 port on the back of the Mega Drive and used to play games online with other players. This was supported by the Sega Meganet service, a network service in Japan for people using the Sega Mega Drive. Debuting in 1991, this was the first time multiplayer console gaming was possible to a second console. However, the service was not very successful and was eventually discontinued. Plans for this service were considered in North America, with the device being renamed the Telegenesis, and was in fact advertised in several early product and accessory line-ups for the console, but these plans were also cancelled.

The game selection included Phantasy Star II-based text adventures, Sonic Eraser (a Sonic the Hedgehog/Columns crossover puzzle game), and a Mahjong title. There were also small games that could be downloaded to the console. In 1995, the service was also started in Brazil. The selection of games was increased and included many titles such as Mortal Kombat II and FIFA Soccer 95.

Third-party accessories such as the Action Replay by Datel and the Game Genie by Codemasters were released as well as converter cartridges that allow Japanese games to be played on American or European machines.

Variations

Main article: Variations of the Sega Mega Drive
Sega Wondermega incorporates the Mega Drive and Mega CD in one unit

The Mega Drive quite possibly received more officially licensed variations than any other console. While only one major design revision of the console was created during its lifespan, each region has its own peculiarities and unique items, while other variations were exercises in reducing costs (such as the removal of the little-used 9-pin EXT. port) or expanding the capabilities of the Mega Drive.

The Model MK-1631 (Mega Drive/Genesis 2) does have a Z80 CPU.[49] Depending on the board revision, the system has either a Zilog Z84C00 or a Custom Sega 315-5676 or similar. Because the Z80 is used for sound production by many games, it is a necessary component. The idea that the redesigned machine has no Z80 came from reports of incompatibility between those models and the Power Base Converter, which provides Sega Master System compatibility.

Majesco's Genesis 3 (single-chip and dual-chip versions) retains the Mode 4 support but has the Master System compatibility removed from the bus controller logic.[13] This renders the Power Base Converter or any other adapter useless. 68000 software can still enable and use Mode 4, however.

One of the 68000's instructions, TAS, is intended for semaphore communication in multiprocessor machines and locks the 68000 bus during memory access.[50] The Sega hardware did not support this unusual bus cycle and ignored the write-back phase. Two games, Gargoyles from Buena Vista Interactive, and Ex-Mutants from Sega make use of the TAS instructions and expect it not to write to memory. As a result, these games work on original Sega machines but not the Majesco Genesis 3, which has correct support for TAS.

Technical specifications

Mega Drive 1 mainboard (PAL)

CPU

Main article: Motorola 68000

The Sega Mega Drive's CPU is a 16/32-bit Motorola 68000 [51] which is is a 32 bit microprocessor sitting on a 16-bit-wide data bus. The maximum addressable memory is 16 megabytes (the M68000 is located to the left of the picture). The 68000 Runs at 7.61 MHz in PAL consoles, 7.67 MHz in NTSC consoles. The Mega Drive also includes a Zilog Z80 as the sound CPU. The Z80 Runs at 3.55 MHz in PAL consoles, 3.58 MHz in NTSC consoles.

The VDP uses a technique called Direct Memory Access (DMA) which is a high speed technique for accessing the VRAM, CRAM and VSRAM. DMA has 3 modes of access which may be applied to VRAM, CRAM or VSRAM. During memory to VRAM/CRAM/VSRAM DMA, the 68000 is stopped, but the Z80 will continue to run as long as it does not attempt to access the 68000 memory space.

Hardware specifications
Processor

16-bit / 32-bit Motorola 68000 (or equivalent)[52] [53] [54] [55] [56] [57]

  • Runs at 7.61 MHz in PAL consoles, 7.67 MHz in NTSC consoles.
  • Some systems contained 68000s manufactured by Motorola licensees such as Hitachi and Signetics. Signetics 68K only found in early revisions as it is known to be inefficient.[58]
  • Has 24-bit and 16-bit address buses, 16 and 8-bit data buses.
  • Additional features are DMA and hardware memory copy mechanism
Secondary processor

Zilog Z80 (or equivalent)

  • Runs at 3.55 MHz in PAL consoles, 3.58 MHz in NTSC consoles
  • Used as sound CPU or the main CPU in Master System compatibility mode.

Video

The Mega Drive has a dedicated VDP (Video Display Processor) for playfield and sprite control. This is an improved version of the Sega Master System VDP, which in turn is derived from the Texas Instruments TMS9918. It contains both mode 4 (for Master System compatibility) and mode 5 (for native 16-bit games). However, Master System programs can switch the VDP into mode 5 and make use of advanced VDP features. This page only discusses mode 5 capabilities.

Images could be output at 256 pixels (32 tiles) or 320 pixels (40 tiles) across and 224 scanlines (28 tiles) or 240 scanlines (30 tiles) down. The 240-line resolutions are only used on 50 Hz (i.e. PAL) displays, as the extra lines end up in the overscan of a 60 Hz (NTSC) signal. Instead, NTSC games use the 224-line resolution to free up more vertical blanking time to send more updates to the VDP. Colors are chosen from a total of 512 possible colors; some games used a small amount of flicker to simulate more colors. Graphics consist of up to 64 sprites on 3 planes. Palettes are stored in color RAM (CRAM) and consist of 16 colors each for a total of 64 colors.[59]

Sprites can be any combination of 8, 16, 24 and 32 by 8, 16, 24 and 32. Up to 20 sprites may be used on a single line and each of these sprites will be on one of the 3 planes. The priority of each sprite can be changed allowing sprites on different planes to appear in a different order than the planes themselves.

Playfields, 2 of the available planes, can both be scrolled horizontally and vertically as a whole. Horizontal scrolling allows for individual character line or scan line scrolling while vertical scrolling is limited to 2 character wide columns.

Graphics Processing specifications
Planes:

4 (2 scrolling playfields, 1 sprite plane, 1 'window' plane), per-tile priority

Sprites: Up to 64 (32H)/80 (40H) on-screen, 16/20 per line, 256/320 pixels per line, per-sprite priority
Palette: 512 colors (1536 using shadow/highlight mode)
On-screen colors: 64 × 9-bit words of color RAM, 4 lines of 15 colors plus transparent, allowing 61 on-screen colors (up to 1536 via raster effects and shadow/highlight)
Screen resolution
  • 256x224 (32Hx28V), 320x224 (40Hx28V), 256x240 (32Hx30V, PAL only), 320x240 (40Hx30V, PAL only)
  • Interlace mode 1 provides no increase in resolution, but still generates a true interlaced signal
  • Interlace mode 2 can provide double the vertical resolution (i.e. 320×448 for NTSC, 320x480 for PAL). Used in Sonic 2 for two-player split screen
Scroll size

Width and height independently set to 32, 64, or 128 cells as VRAM allows

Pixel Depth 4-bits

Audio

There are two primary sound chips which are both controlled by the Z80; the Yamaha YM2612 Frequency Modulation (FM) chip and the Texas Instruments SN76489 Programmable Sound Generator (PSG) chip. The FM sound synthesis IC resembles the Yamaha YM2151 (used in Sega's coin-op machines) and the chips used in Yamaha's synthesizers. There is 8 kilobytes of dedicated sound RAM available to them.

The Yamaha uses six FM channels, four operators each and runs at 7.67 MHz (7.61 MHz in PAL machines). The sixth channel can be used as a 8-bit digitized audio channel or as a regular FM channel. The use of the digitized audio allows for stereo sound and is output only through the headphone jack on model 1 systems and through AV out on model 2 systems along with mono signal.

The SN76489 device is built into the VDP and has a four-channel PSG (Programmable Sound Generator). It has three square wave channels, one white noise channel and programmable tone/noise and attenuation. It is mainly used for Master System compatibility mode but can be used to supplement FM channels.

Sound Processing specifications
Main sound chip

Yamaha YM2612

  • Six FM channels, four operators each; channel 6 can be used for PCM data or as a regular channel
  • PCM channel has no DMA, and requires data to be written to the chip from the Z80
  • Programmable low-frequency oscillator and stereo panning
  • Runs at 7.67 MHz (7.61 MHz on PAL machines).
  • 52 kHz sampling rate
Secondary sound chip

Texas Instruments SN76489 compatible device built into VDP.

  • Four-channel PSG (Programmable Sound Generator)
  • Three square wave channels, one white noise channel
  • Programmable tone/noise and attenuation
  • Used for Master System compatibility mode as well as to supplement FM
  • Different random noise generation compared to a real SN76489/SN76489A chip

Memory

Memory specifications
Boot ROM
  • 2 KB (KiB)
  • Known as the "Trademark Security System" (TMSS)
  • When console is started, it checks the game for certain code given to licensed developers
  • Unlicensed games without the code are thus locked out, but if a game is properly licensed, the ROM will display "Produced by or under license from Sega Enterprises Ltd."
  • Boot ROM is not present on earlier versions of the Mega Drive and Genesis and some earlier games not designed for the TMSS may not work in later consoles
Main RAM
  • 64 KB
  • Part of M68000 address space
Video RAM
  • 64 KB
  • Cannot be accessed directly by CPU, must be read and written via VDP (Video Display Processor - see below)
Secondary RAM
  • 8 KB
  • Part of Z80 address space
  • Used as main RAM in Master System compatibility mode
Audio RAM
  • 8 KB
Cartridge memory area (ROM space)

Inputs and outputs

Input and output list
RF output

RCA jack connects to TV antenna input

  • Exists on original model European and Asian Mega Drive and North American Genesis only
  • Other models must use external RF modulator which plugs into A/V output
A/V output

DIN connector with composite video, RGB video, and audio outputs

  • Mega Drive and the first model Genesis have an 8-pin DIN socket (same as Sega Master System) which supports mono audio only
  • Mega Drive 2, Multimega, and other models have a 9-pin mini DIN socket with both mono and stereo audio
Power input
Headphone output

Amplified 3.5-mm stereo jack on front of console with volume control

  • Exists only on original model Mega Drive and Genesis units
  • Provides stereo audio on models which have the mono 8-pin DIN A/V output
  • Also suitable for passive speakers
  • Can be used for mixing audio from the SegaCD
"EXT" port

DE-9F (9-pin female D-connector) on back of console

  • Used with the Meganet modem peripheral, released only in Japan
  • Exists on all first-model Japanese Mega Drive units, and on early American Genesis and PAL (European, Australasian and Asian) Mega Drive units
Control pad inputs

Two DE-9M (9-pin male D-connectors) on front of console

Expansion port

Edge connector on bottom right hand side of console

  • used almost exclusively for Sega Mega-CD connection
  • not present on Genesis 3 model
  • also used for the Sega Genesis 6 Cart Demo Unit (DS-16) in stores.

Modifications

It is possible to overclock the Motorola 68000 CPU in some cases in excess of 300%, though it may not be completely stable beyond a certain point on each console.[60] Overclocking the CPU does not speed up the games, but actually eliminates slowdown that some games are plagued by (such as Sonic 2 splitscreen). The reason for this is most games do the processing for a video frame, then wait for the vertical blank interrupt. If the processor runs faster, it simply finishes the processing for the video frame earlier, and waits for the vertical blank interrupt for a longer period of time.

Another possible modification is to replace the stock 68000 processor with a 68010. Since the CPU isn't socketed, this requires the removal of the old CPU, and soldering in of the new. The 68010 is a pin-compatible enhanced version of the 68000, which is a bit more efficient internally and offers some new features. Also, the DAC's digital audio output may sound cleaner and less distorted because the 68010 has a "loop mode" to run small loops faster, which may allow the Z80 to receive PCM data faster. However, the 68010 is not 100% object code-compatible with the 68000, so machines modified with a 68010 processor are not able to run certain games properly, such as Sonic 3, Sonic and Knuckles, Street Fighter II, Red Zone, and a few others.

Other mods have been made to the console, such as switches to instantly switch between 50 Hz and 60 Hz, language settings, the ability to fit Japanese carts and various paint finishes.

See also

References

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  8. ^ Business Week staff (1999). Business Week - Nintendo's Market Share 1990. p. 60. {{cite book}}: |last= has generic name (help)
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  10. ^ Planet Dreamcast staff. "Sega History". http://www.planetdreamcast.com. Retrieved 2007-10-18. {{cite web}}: External link in |work= (help)
  11. ^ "The history of the Sega Mega Drive". www.skillreactor.org. Retrieved 2008-03-06.
  12. ^ Szczepaniak, John (2006-09-12). "Retroinspection: Mega Drive". www.sega-16.com (Reprinted from Retro Gamer Magazine (27)). Retrieved 2007-11-08. {{cite web}}: Check date values in: |date= (help)
  13. ^ a b c d e Console Database Staff. "Sega Mega Drive/Genesis Console Information". http://www.consoledatabase.com. Retrieved 2007-10-18. {{cite web}}: External link in |work= (help)
  14. ^ Blake Snow (2007-05-04). "The 10 Worst-Selling Consoles of All Time". GamePro.com. Retrieved 2007-05-28. {{cite web}}: Check date values in: |date= (help)
  15. ^ a b Greg Gillis (2006-06-07). "Fors Yard - A Chronological Retrospective Of The Sega Genesis". Retrieved 2007-09-26.
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