Sega Mega Drive/Sega Genesis
(Redirected from Sega Megadrive)
Categories: Sega consoles | Fourth-generation video game consoles
The Sega Mega Drive/Sega Genesis was a 16-bit video game console released by Sega in Japan (1988), Europe (1990) and most of the rest of the world as the Mega Drive. It debuted under the name "Genesis" in North America (1989), as Sega was unable to secure legal rights to the Mega Drive name in that territory.
History
Development
Although the Sega Master System had proved a success in South America and Europe, 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 with 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 was making were very popular, Hayao Nakayama, Sega's CEO at the time, decided to make their new home system a 16-bit one. The final design worked great and fit in well with Sega's three new arcade boards; the Mega-Tech, Mega Play, and the System C. Any arcade game made for these systems could easily, and thus rapidly, be made to work on the new console (a process known as porting).
The first name Sega thought of for their console was the MK-1601, but Sega decided to use "Sega 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. The U.S. version went by the name Genesis due to a trademark dispute, while the South Korean versions were called Super Gam*Boy (수퍼겜보이) and Super Aladdin Boy (transliterated from 수퍼알라딘보이; this was the Korean version of Mega Drive 2). Those consoles were licensed and distributed by Samsung.
Japanese release
The Mega Drive was released in Japan in October 29, 1988 for ¥21,000, almost exactly a year after the first console popularly classed as a 16-bit machine - the NEC PC Engine. Although this initially caused slow sales, the Mega Drive soon eclipsed the earlier machine in popularity.
European release
The European release was on November 30, 1990 in the United Kingdom, priced at £189.99. The first UK shipment of 30,000 units was sold at retailers Comet, Dixons, Rumbelows and Toys R Us (Foulger, 2000).
North American release and further development
Sega announced their North American release date for the system in 1987, making a point of the fact that it was the first true 16-bit console. 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.
The Genesis initially competed against the 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 and the huge catalog of popular games already available for it. In an attempt to build themselves 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 anxious for more "grown-up" titles with more mature content and/or more in-depth game play. As such, Sega released titles such as Altered Beast and the Phantasy Star series. Although the NES and Nintendo's impending SNES were still threats to Sega's market share, they had forced the theoretically competitive TurboGrafx 16 system into relative obscurity, thanks in part to NEC's poor North American marketing campaign.
Eventually, the main competition for the Genesis became Nintendo's 16-bit SNES, over which it had a head start in terms of user base and number of games, reversing the problem Sega had faced against the NES. 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 up-to-then stranglehold on the number one console position in the USA. 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, at least up until that point.
By 1992, Sega was enjoying a stronghold on the market, holding a 55% market share in North America. Faced with a slight recession in sales and a brief loss of market share to the SNES, Sega again looked to Sonic to rejuvenate sales. The release of the highly-anticipated Sonic the Hedgehog 2, coinciding with an aggressive ad campaign that took shots at Nintendo fueled Genesis sales a while longer and boosted Sega's market share percentage back up, to an astounding 65%.
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 circuit boards required for each unit.
Aside from the release of the Sega CD and 32x add-ons for the Genesis/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, which would allow subscribers to "download" games on a month-by-month basis.
Decline in Market Share
The failures of the Sega CD and 32X, 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, Playstation, and N64 signaled that the 16-bit era was drawing to a close. Interest in the Genesis suffered greatly as a result, 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. (see Video game market).
Resurgent popularity in North America
In recent years, the Genesis has had something of a revival, led largely by the grey market trade in both unlicensed cartridges (for instance, the biblically-themed output of Wisdom Tree) and dumped ROMs, which are played through emulators such as Gens. There is also a trend towards home programming of the Genesis, using the PC-based SGCC.
In the 2000's, there came a trend toward plug-and-play TV games, and Radica has released a licensed, self-contained version of the Sega Genesis for the North American market, called Play TV Legends Sega Genesis, which contains six popular games in a 'Genesis' control pad. It does not have a cartridge slot, and thus is a dedicated console. However, Benjamin Heckendorn, of Atari portablizing fame, has proven that is in fact possible to connect a cartridge slot to this with some soldering.
Variations of the Mega Drive and Genesis
Sega Mega Drive (Japan)
- Japanese-language settings
- Headphone jack
- AUX Port marked A/V OUT
- 9-pin EXT. port
- Supports Sega Mega-CD and Sega Super 32X
- Has a cartridge lock
- Gloss black finish
- On the circular molding, in purple is the text "AV Intelligent Terminal High Grade Multipurpose Use". At the bottom of the circle is a purple square section with a red power indicator LED.
- Cooling vents are located on the left side.
- "Mega Drive" is printed in white on the lower right of the console to the left of the SEGA logo.
- The reset button and start button on the joypad are blue.
Sega Mega Drive (Europe, Australia, and New Zealand)
- Converted to display PAL 50-Hz signal
- English-language settings
- Unable to play Japanese Mega Drive games due to shape of cartridge and console. However, adapters were sold to play Japanese games in the European model.
- Cartridge lock removed
- The text "High Definition Graphics · Stereo Sound" located behind cartridge port (only found on earlier models).
- The reset button and the start button are white.
- Model number 1600-05 (original model), 1601-05 (second variation without "High Definition Graphics - Stereo Sound" text or EXT port)
Sega Mega Drive (Asia)
This console is a variant of the European Mega Drive and often mistaken for a Japanese Mega Drive.
- No text printed around circle
- Larger "16-Bit" logo used
- "Start" and "Reset" button are blue
- Identical to European Mega Drive with PAL output
- Used Japanese Mega Drive logo and packaging similar to the Japanese version
- Games packaged the same as European with the same labeling. However, the cartridges are shaped like Japanese Mega Drive games.
Sega Genesis (North America)
- Headphone jack
- AUX Port marked A/V OUT
- 9-pin EXT. port
- Supports Sega CD and Sega 32X
- Gloss black finish
- Cooling vents are located on the left side
- Reset and start buttons are gray
- "Sega Genesis" in white on top of machine below cartridge slot
- Model number MK-1601
Sega Mega Drive 2 (Japan)
- New squared shape
- No headphone jack
- One custom multi-output for picture and sound
- Red colored flaps on cartridge port
- The text "High Grade Multi Purpose Intelligent Terminal" located behind cartridge port.
- Packaged with six-button controller standard.
- No power LED
Sega Mega Drive 2 (Europe, Australia, and New Zealand)
- New squared shape
- No headphone jack
- A/V port switched to one custom multi-output for picture and sound (previously, only mono sound was used, as the stereo sound came through the headphone jack)
- Push-button power switch
- Power port smaller, and different AC adapter used
- RF out port removed
- Auto-switching RF Lead included
- Model number MK-1631-50
Sega Genesis (North America, second model)
Note: This model was not officially named "Genesis 2".
- New squared shape
- No headphone jack
- One custom multi-output for picture and sound
- Has a power LED
- "Genesis" in square above cartridge slot
- Model number MK-1631
Sega Genesis 3 (North America)
- Announced in 1997 as a "budget" version of the Sega Genesis
- Manufactured by Majesco
- Released in 1998 as the "Genesis 3" in North America only
- Retailed for $50
- Due to lack of an expansion port, unable to link with Sega CD
- Model number MK-1641
Other variations of the Mega Drive and Genesis
The Wondermega/X'eye
Wondermega (named X'eye in North America) - A combined Mega Drive and Mega-CD sold by Victor (known as JVC outside Japan) - Never released in Europe
- Improved sound capabilities
- MIDI Port
- 2 Microphone Inputs
- S-video out
- Packaged with a CD called Game Garden that had Flicky (quiz game) and Pyramid (puzzle game.) The CD is compatible with CD+G (CD and Graphics) enabled CD Players.
- Another release came with Compton's Interactive Encyclopedia, Prize Fighter, and a Karaoke CD+G demo CD.
- Later Japanese pack had a platform game called 'Wonderdog' by Core.
- Supported the "Wonder CD" pheripheral that allows someone to create music and connect to MIDI-enabled devices.
- Supported a music keyboard called the "Piano Player" that allowed you to create music and learn to use the keyboard.
- Later given a redesign with a softer, more curved look. Some of the extra features were removed, and the joypads were remodeled infrared joypads.
Sega Multi-Mega/CDX
Main article: Sega CDX
Sega Multi-Mega (named CDX in North America) - An integrated Mega Drive/Genesis and Mega-CD/Sega CD console with the capability of also functioning as a portable CD player, aimed at the more affluent market. The British release sold at £350.
- No built-in screen.
- Could function as a portable CD player. CD control buttons are on the front of the console. A back-lit LCD displayed the track number. An extra line out port was provided for stereo equipment.
- Powered by 2 AA batteries when operated as a portable CD player. The unit must be powered by an AC adapter to play video games.
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.
The Mega Jet and Genesis Nomad
Main article: Sega Nomad and Sega Mega Jet
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 neccesary 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. 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, rendering moot any complaints of overpricing, the handheld did not garner enough support to continue.
Pioneer LaserActive with Mega Drive/Genesis module
Main article: LaserActive
LaserActive was the name given to Pioneer's CLD-A100 LaserDisc player. The player was both a Laserdisc and CD player right out of the box, while the addition of add-on modules manufactured by Sega and NEC could make the unit function as a gaming system as well. Sega's PAC-S1 module, released at a price of 39,000 Yen, allowed users to play Mega Drive, Mega-CD and specially created Mega LD games through the player. The Mega LD games were breifly thought to be the next evolution in gaming, mainly because the massive storage capacity of the Laserdiscs they were printed on meant that games could be multiple times large than before and include uncompressed full-motion video and digital audio as well as surround sound, all features that have become commonplace on modern DVD-ROM based systems.
An NEC module, PAC-N1, gave the unit the capability to play Turbografx 16 games. The addition of either module also made the unit compatible with either Sega or NEC brand control pads. A later module was released for the unit by Pioneer, allowing it to function as a full-feature Kareoke machine.
Pioneer later engineered 3D glasses for the system (Kit GOL-1), the glasses required an adapter to be attached before they could function with the player, but each adapter could support a pair of the goggles, allowing 2 users to play in 3D simultaneously.
The LaserActive unit unfortunately didn't survive for long. Its high cost and the general market disinterest in Laserdisc made the system a hard sell.
The Teradrive
The Teradrive was an 80286 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. Only the top-of-the-line model was supplied with a hard disk. A special monitor (sold separately) was available, which could display both 15kHz RGB video signals from the Mega Drive hardware and the 31kHz 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, as shown with the Puzzle Construction program. It was also possible for Mega Drive software to be run from the PC's RAM.
The Mega PC
The Mega PC was 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-scan (15kHz/31kHz) 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 and European markets.
Miscellaneous
- Some MSX machines released only in Arab countries by a company named Universal, which along with MSX software could also (allegedly) play Mega Drive games.
- The A330 MSX had a cartridge port on the top of the machine. It has "Painting", "Calendar", "Arabic Writing", and "English Writing" as its programs.
- The AX990 had 50 programs. They are likely to be an unofficial multicart or other MSX programs.
Screenshots
 Space Harrier II |
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Sonic the Hedgehog |
John Madden Football 93 |
Ecco the Dolphin |
Mortal Kombat II |
Technical specifications
CPU
Main processor: 16-bit Motorola 68000 (or equivalent)
- Runs at 7.61 MHz in PAL consoles, 7.67 MHz in NTSC consoles, nearly 0.96 MIPS with 32bit arithmetic - theoretical peak of 1.92 million 32bit adds/second
Secondary processor: 8-bit Zilog Z80 (or equivalent)
- Runs at 3.55 MHz in PAL consoles, 3.58 MHz in NTSC consoles
- Used as main CPU in Master System compatibility mode.
Contrary to popular belief, Model MK-1631 (Mega Drive/Genesis 2) does have a Z80 CPU. Depending on the board revision, the system has either a Zilog Z84C00 or a Custom Sega 315-5676 or similar. Since 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, but the true prohibiting factor is the shape of the device. The redesigned cartridge port is too far forward on the system to connect a Power Base Converter without first removing its plastic housing.
Memory
Boot ROM: 2 KB
- 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
- 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
- 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
Cartridge memory area: up to 4 MB (32 Megabits)
- Part of M68000 address space
- Game cartridges larger than 4 MB must use bank switching
Graphics
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.
Planes: 4 (2 scrolling playfields, 1 sprite plane, 1 'window' plane)
Sprites: Up to 80 on-screen, depending on display mode
Palette: 512 colours
On-screen colors: 64 × 9-bit words of color RAM, allowing 61 on-screen colors (up to 1536 using raster effects and Shadow/Hilight mode)
Pixel resolution: Up to 320×240 (40×30 cells) for PAL, and up to 320×224 (40×28 cells) for NTSC
- Interlaced modes can provide double the vertical resolution (i.e. 320×448 for NTSC, 320x480 for PAL). Used in Sonic 2 for two-player split screen
Sound
Main sound chip: Yamaha YM2612
- Six FM channels, four operators each
- Programmable low-frequency oscillator and stereo panning
- Sixth optionally used for 8-bit digital audio
Secondary sound chip: Texas Instruments SN76489
- Four-channel PSG (Programmable Sound Generator)
- Three square wave channels, one white noise channel
- Programmable tone/noise and attenuation
- Used for Master System compatability mode
Inputs and outputs
RF output: 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, and audio outputs
- Mega Drive has 8-pin socket (same as Master System), supports mono audio only
- Mega Drive 2, Multimega, and other models have 9-pin mini DIN socket with both mono and stereo audio, and s-video
Power input: requires 9-10 volts DC, 0.85-1.2 A depending on model
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
- Also suitable for passive speakers
"EXT" port: 9-pin D socket for Meganet modem connection
- exists on all Japanese and Asian Mega Drive 1 units, and on early European Mega Drive 1 units
Control pad inputs: 2 × 9-pin D connectors on front of console
Expansion port: Edge connector on bottom right hand side of console for Sega Mega-CD connection
Miscellaneous
Signal/Noise Ratio: 14 dB
The EXT port on the original Genesis/Mega Drive console is used with a modem peripheral that was only released in the Japanese market. The port operates identically to the two joystick ports, but has a female DB9 connector instead of a male DB9 one. The lines to this port also appear to have been used for game selection on arcade adaptations of the MegaDrive/Genesis hardware.
The Stereo Headphone port on the front of the first model was either used for stereo headphones or speakers and/or used for mixing stereo sound for the Sega CD.
The Expansion port most often used with the Sega CD was also used for the Sega Genesis 7 Cart Demo Unit in stores.
Some emulation software can save game music to a format known as GYM. It works by recording the operation of the sound system to a destination file (the .gym file). The internal state of the emulator's sound chip code is sampled 60 times per second, and dumped to the file. While initially popular due to the lack of any serious competition the format does not offer a high fidelity reproduction of the original sound output, tends to produce very large files and was difficult to produce for PAL titles given the simplifications necessary for emulators at the time. The more-complete VGM format has now grown to replace it, which is capable of logging changes at up to 44100Hz, meaning that most sound may be accurately reproduced.
The Power Base Converter
One of the key design features of the console is its compatibility with its immediate predecessor, the Master System. The 16bit design is based upon the 8bit design, albeit enhancened and extended in many areas. As the cartridge slot is of a completely different shape, Sega released the Power Base Convertor, a separate device that sat between a Master System cartridge and the new shape of cartridge slot. Due to the high level of backwards compatibility, the Power Base Converter does not contain any Master System components.
In order to achieve backwards compatibility, the original Master System central processor and sound chip (the z80 and SN76489) are included and the new Video Display Processor is capable of the Master System's "Mode 4" display. The system's bus controller chip (later integrated with the I/O chip into a single multi-purpose ASIC) can put either the Z80 or 68000 in primary control of the system, depending on whether the Power Base Converter or a regular game is inserted into the cartridge slot.
Trivia
An adapter to make the machine capable of playing Game Gear games was never released. Although based upon the Master System, the Game Gear's hardware is sufficiently different that such a device would require extra hardware for complete compatability.
Majesco's Genesis 3 (single-chip and dual-chip versions) retains the Mode 4 support but has the Master System compatability removed from the bus controller logic. 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 instructions, TAS, is intended for semaphore communication in multiprocessor machines and locks the 68000 bus during memory access. The Sega hardware did not support this unusual bus cycle and ignored the write-back phase. One game, Disney's Gargoyles, uses the TAS instructions and expects it not to write to memory and as a result it works on original Sega machines but not the Majesco Genesis 3 which has correct support for TAS.
It is possible to overclock the Sega Genesis' Motorola 68000 chip by almost over 300% (the current known world record is 25.4 MHz), though it may not be completely stable beyond a certain point on each console. In a guide at Epic Gaming, the How-To carefully explains this process. Some chips can clock higher than others, and other factors come into play such as how tolerant the system's arbiter, RAM or VRAM are to overclocking. You can perform the process without buying anything (if you have wire, solder, a soldering iron, and 1 or 2 switches), though you can only overclock the chip to 13.4MHz without the purchase of inexpensive oscillators. Overclocking the Genesis may seem a bit odd; however, in some games, such as Sonic the Hedgehog 2, the Genesis' 68000 CPU would struggle to display many sprites or crunch a heavy level of physics calculation; for example, after you get hit and the rings fly out of your character. Overclocking the chip by even 3MHz can totally eliminate this. The overclock can be achieved by simply linking with a wire the chip's CLK pin (usually pin 15, it depends on the chip) to pin B15 of the cartridge slot's pin, which carries a 13.4MHz signal, thus overclocking the chip; however it is advised to switch to 13.4 MHz after boot with a halt/clock switch pair (as is outlined in the guide) to reduce the likelihood of glitches or sound problems.
Sales
The Sega Mega Drive sold 30 million units worldwide - including 22 million in the United States alone.
Bibliography
Foulger, C. (2000). Sega Megadrive Frequently Asked Questions, version 2.2.
Maxim, et. al. (2003) SN76489 notes, 5th revision
See also
| Major video game consoles |
| The first home video games |
|---|
| Magnavox Odyssey | Coleco Telstar | Pong |
| Pre-crash 8-bit systems |
| Atari 2600 | Magnavox Odyssey² | SG-1000 | Intellivision | Colecovision | 5200 |
| 8-bit era |
| NES | Master System | 7800 |
| 16-bit era |
| SNES | Mega Drive/Genesis | TG16 | Jaguar |
| 32-bit / 64-bit era |
| Nintendo 64 | PlayStation | Saturn |
| Sixth generation era |
| Dreamcast | GameCube | PS2 | Xbox |
| Seventh generation era |
| PlayStation 3 | Revolution | Xbox 360 |
- List of Sega Genesis games
- List of Sega Mega Drive games
- Sega CD
- Sega 32X
- Sega CDX
- Sega Mega Jet
- Sega Nomad
Related Systems
es:Sega Genesis eo:Mega Drive fr:Megadrive gl:Mega Drive nl:Sega Mega Drive ja:メガドライブ no:Sega Mega Drive nn:Sega Megadrive pt:Mega Drive fi:Sega Mega Drive sv:Sega Mega Drive