Genesis

Overview

Released as the Sega Mega Drive in Japan, Europe, South America, and Oceania, and as the Sega Genesis in North America, it is Sega's 16-bit console. It was the successor of the 8-bit Sega Master System and predecessor to the 32-bit Sega Saturn.

The console hardware had both a 16-bit Motorola 86000 for the main console CPU, and 8-bit Zilog Z80 CPU for the sound chip. Both CPU chips were commonly used together in Sega arcade cabinets at the time--as well as arcade cabinets in general during the late 80s and early 90s. Sega's goal was to give home consumers a taste of arcade quality gameplay, made popular by their System-16 arcade cabinets, where hit games like Golden Axe, Altered Beast, and Alien Syndrome were frequently played in the arcades. An image from the video game Altered Beast was even used as the console box art, to help market it as a 16-bit arcade console. The console was not as powerful as their System-16 and future 16-bit arcade cabinets, however. The console used a 9-bit color palette, compared to a 16-bit color palette used in their early 16-bit arcade cabinets. The console could only display 80 sprites on screen, compared to the 128 sprites from their System 16 cabinets. Sega also used a lower grade version of the sound chips used in most arcade cabinets at the time. The basic structure, however, allowed for many good (but not perfect) arcade ports of their games, as well as games from other developers.

It had a production run lasting from 1988, when it was first released in Japan, to 1997, when it was finally discontinued. It sold over 40 million units worldwide, over half of which were sold in North America alone. While its performance in Japan was underwhelming, coming third place behind both the SNES and PC Engine, the Mega Drive was Sega's most successful console worldwide, outselling the SNES in the overseas territories of North America, Europe, South America, Oceania, and South Korea.

The console's best-selling stand-alone game was Sonic the Hedgehog 2, with over 6 million cartridges sold, while its best-selling bundled game was the original Sonic the Hedgehog, with over 15 million units sold.

To make it seem cooler than its main rival, the Super Nintendo Entertainment System (SNES), Sega's Marketing Department came up with the term "Blast Processing" to imply that the Genesis/Mega Drive had more power and was more capable of rendering sprites on screen faster than the SNES. While "Blast Processing" was purely a marketing term, the Genesis/Mega Drive did in actuality run at a higher clock speed than the SNES, enabling many games to feature fast scrolling (often with many background layers in parallax) and a large number of sprites on screen.

During its nine-year production run, it was expanded upon numerous times. These add-ons included the Power Base Converter, allowing it to play 8-bit Master System games, as well as the Sega CD and the 32X. Additionally, two later models of the Genesis were released.

The Genesis had two main versions of its controller. The first was slightly larger than the other, with three face buttons and a slightly "sharp," hard-plastic thumb pad. Although this controller was initially well-received, as the popularity of games like Street Fighter II rose, there was demand to produce a six-button controller.

Sega finally did release a six-button controller with a slightly streamlined look and feel, a softer thumb pad, and naturally three more face buttons. Many later Genesis games recommended the use of this secondary controller (many of them fighting games), as games that were played with the original controller and designed for the new six-button one would need to tap the start button to switch the three face buttons to the function of the other three.

Accessories

The Sega Mega Drive/Genesis supported the following accessories:

• XE-1AP, released by Dempa Micomsoft only for Japan in 1989. It featured an analog thumbstick, analog slider, four shoulder buttons, and two grip handles. It was supported by After Burner II (1990), Ayrton Senna's Super Monaco GP II (1992), Fastest 1 (1991), Galaxy Force II (1991), and Musha Aleste (1990).
• Sega Activator, released by Sega in 1993. It allowed full-body motion control, but had limited motion detection.
• Sega VR, planned for release in 1994 but eventually cancelled. It was a virtual reality headset with head-tracking capabilities.

Network and Cable Support

In Japan, the Sega Mega Drive had network service available beginning in 1991. In order to use the service, players had to attach a Mega modem (which had a connection speed ranging from 1,600 to 2,400 bits/s) to the DE-9 port on the console. The few games available for download onto the Mega Drive were Sonic Eraser and Phantasy Star II Text Adventures. In 1995, the service reached Brazil, where two more games were available: Mortal Kombat II and Fifa Soccer '95. The service was not successful, and was eventually discontinued.

Despite this, Sega teamed up with TCI and Time Warner in 1994 to release the Sega Channel in the United States. The Sega Channel was a hardware add-on meant to be placed on top of the Genesis cartridge slot. The add-on allowed players to download games directly to their Sega Genesis consoles and play the games for a monthly fee. They did this by connecting a coaxial cable (the same kind used on cable boxes) to the back of the cartridge add-on. One could then choose to browse games from a variety of menus. Categories like shooter, role playing, platforming, etc. contained many popular Genesis titles people could download and play. After 30 days the games available would change. Usually, the most popular games were kept in service while the games people hardly played were replaced with other games. The Sega Channel also kept track of new games that were released. The games were usually available a month after their official release dates. Japanese import games were also available to subscribers. The activation fee was $29.95, and the monthly fee was $14.95. The service lasted until 1998, when the 32-bit era was established with the Sega Saturn, and the Sony PlayStation. The Sega Channel was also the only way American gamers could play the Genesis last two best games, Alien Soldier and Pulseman.

Sega Genesis Nomad

The Sega Nomad was a failed handheld version of the Genesis console. Released in October of 1995 at a price of $180 USD, the Nomad featured a 3.25 inch color screen and ran on six AA batteries.

Interestingly, the Nomad was a fully functional Genesis home console in addition to being a handheld device. Television connectivity was provided through an A/V slot on top of the unit. For single player games, the Nomad itself functioned as the controller, but two player gaming was possible using a controller port on the bottom of the device. This port accepted standard Genesis controllers.

The Nomad suffered from problems that plagued Sega's other handheld, the 8-bit Game Gear. Both machines were notoriously power-hungry thanks to their (relatively) powerful processors and high quality backlit LCD screens. The Nomad was capable of depleting its batteries in two hours, which lessened its appeal as a portable device. Additionally, despite being advertised as a wholly-capable Genesis console, the Nomad was functionally incompatible with the various Genesis add-ons Sega had released such as the Sega CD and 32X. These compatibility problems were due to the shape of the Nomad, and the inability to mount these accessories on its portable form factor.

Faced with competition from Nintendo's hugely successful Game Boy, the Nomad faltered at market. By the time Sega ceased production, it had only managed to sell 1 million units.

PC/Mega Drive Hybrids

In an effort to sell the Genesis hardware to a wider audience, two different PC and Mega Drive hybrid computers were created: the TeraDrive in Japan (manufactured by IBM), and the Mega PCin Europe (manufactured by Amstrad).

While the Mega PC was an isolated ISA card that could only be used when the PC was inactive, the TeraDrive hardware allowed PC software and Mega Drive games to interact with each other.

Unfortunately, both the TeraDrive and the Mega PC were hampered by low spec PC hardware (286 and 386SX respectively) that had to compete against 486 and Pentium-based PCs.

Launch Titles

United States

The Sega Genesis launched along with the following 7 games in the US August 14th 1989.

• Space Harrier II
• Thunder Force II
• Tommy Lasorda Baseball
• Last Battle
• Altered Beast
• Alex Kidd in The Enchanted Castle
• Ghouls n' Ghosts

Hardware Specifications

CPU (Central Processing Unit)

• Main Processor Unit: Motorola 68000 at 7.67 MHz
• Secondary Processor Unit: Zilog Z80 at 3.58 MHz

Note: The Zilog Z80 is used to control the sound chip.

Graphics

• Maximum Color Palette: 512 (9-bit color)
  
  • 64 colors on screen at once
• Maximum Sprites On Screen: 80
• Screen Resolution: 256 x 192 - 320 x 448
• Possible AV Outputs
  • RF (Radio Frequency Unit with Coaxial Cable)
  • Composite (RCA Cable)
  • RGB (RGB SCART Cable)

Sound

• Yamaha 2612 Sound Chip
  • 6 Channel FM (Frequency Modulation) at 7.67 MHz
• Texas Instrument Programmable Sound Generator (version Ti-SN76489)
  • 4 Channels at 3.58 MHz
• Sample Rate 22 KHz

Note: The sixth FM channel on the YM-2612 can be used as a 8-bit PCM. Doing so disables the FM channel.

Note: The original sample rate of the YM-2612 was 52KHz, however the sound chip was compressed down to 22KHz on the original Model 1 Genesis. Model 2 had both compression and a filter added to mask the distortion caused by lowering the original sample rate. Unfortunately, this didn't work. This is why you hear little distortion on the Model 1 Genesis, and a lot of distortion on the Model 2 version, which eliminated the direct headphone link to the sound chip, and relied on stereo RCA cables instead. Later revisions fixed some of the sound issues.

Note: The PSG Ti-SN76489 was the same sound chip used in the Sega Master System. This allowed backwards compatibility with the Genesis. This option, however, was abandoned by the time Model 2 was released and became the norm.

Memory

• Main Memory: 64KB
• Video Memory: 64KB
• Sound Memory: 8KB (from Z80)

Nomad Specifications:

Model Versions

Model 1

Model 1 is the original design of the Sega Genesis. It has the logo High Definition Graphics above the Sega Genesis label. It has a headphone jack input for stereo sound. Model 1 only supported RF and Mono Composite outputs like the original Nintendo. It has an expansion port for hardware add-ons for things like the Sega CD.

Model 2

Model 2 was the redesign of the Sega Genesis, shortly after the Super Nintendo became popular. It got rid of the headphone inputs, as this model supported full stereo composite and component outputs. Sadly, the redesign of the circuits caused a sound distortion that made the quality poor. Later, the sound issues were improved somewhat with the VA3 & VA4 motherboards. The Sega CD was also redesigned for Model 2 to fit the new look.

Model 3

Model 3 came out during the 32-bit era. It's a compact version of the Sega Genesis. It has no expansion slot for add-ons. However, it does have output support for S-Video, which separates the color signal from the contrast making the picture quality much better. S-Video inputs can be found on all modern television sets.

Model 4

Sega Genesis 4. also known as Firecore and Blaze Mega Drive, released in 2008, is an officially licensed console using an software emulator rather than actual hardware, and comes with a selection of games preinstalled (the number varies by region - the US release has 20 games, the European Blaze console has 15), as well as a slot to play Genesis cartridges. It does not support the Sega CD or 32X. The emulator has a number of compatibility problems, such as being unable to play the music for some cartridge based games, most notably Sonic the Hedgehog 1 and 2.

In Brazil another console using model number 4 exists, TecToy Mega Drive 4, which like the Firecore/Blaze uses emulation rather than original hardware, but lacks a cartridge slot, and instead has 87 games pre-installed, some of which are ports of more recent titles, like The Sims 2 and FIFA Soccer 08, as well as an Guitar Hero clone titled Guitar Idol. It does support SD cards for MP3 playback and Rom files.