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Sega Mega-CD

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Mega CD Japanese logo.png
MegaCD JP 2.jpgMegaCD2 JP 2.jpg
Fast facts on Sega Mega-CD
Manufacturer: Sega
Release Date RRP Code
Sega Mega-CD
JP
¥49,800 HAA-2910
Sega Mega-CD
US
$299.95[1] 1690
Sega Mega-CD
UK
£269.99[3] 1690-18
Sega Mega-CD
FR
1,990[4]F MK-4102-50
Sega Mega-CD
DE
DM 529,-[5] MK-4102-50
Sega Mega-CD
ES
?Ptas MK-4102-50
Sega Mega-CD
IT
1690-18
Sega Mega-CD
SE
KR3,495kr 1690-18
Sega Mega-CD
AU
$699 1690-18
Sega Mega-CD
BR
R$? ?
Sega Mega-CD
KR
₩398,000 SPC200CR
Sega Mega-CD
TW
NT$? ?
Sega Mega-CD
AS
? 1690-11

The Sega Mega-CD (メガCD), known as the Sega CD in North America and Brazil, and CD Aladdin Boy (CD 알라딘 보이) in South Korea, is a hardware add-on developed by Sega for the Sega Mega Drive.

As the names suggest, it allows a Mega Drive to run compact discs, be it proprietary Mega-CD software, audio CDs or CD+G discs. It also acts as an upgrade to the Mega Drive hardware, sporting an extra processor and extra RAM. The Mega-CD was first released in 1991 and was supported alongside regular Mega Drive cartridges.

Hardware

The Mega-CD comes in many forms, but in all cases the hardware adds the capability of reading compact discs, technology which in the late 1980s and early 1990s, was becoming a more affordable storage option than the traditional video game ROM cartridge of previous console generations.

A traditional Mega-CD does not act as a stand-alone unit, and needs to be hooked up to a Mega Drive via the expansion port located on the right hand side of the console. Mega-CDs do, however, require their own AC adaptor, meaning that in order to play Mega-CD games, two sockets will be occupied by the upgraded console.

Though one would expect the Mega-CD to simply give the Mega Drive access to compact discs, it in fact adds extra processors, memory and audio features as well, all of which can only be utilised by CD software. The Mega-CD does not, however, solve the issue of graphics, which aside from the ability to scale and rotate sprites on the fly, remain identical to the standard Mega Drive system.

The Mega-CD also offers stereo sound RCA connectors. The Mega Drive on its own will output a monaural audio signal to the television, with stereo only being available through the headphone port located at the front of the console. An external connection from the Mega Drive to the Mega-CD will allow all games to play through the television in stereo.

The Mega-CD can be used in conjunction with a Sega 32X to run one of the six Sega Mega-CD 32X games. Alternatively it can be used to just play regular 5-inch or 3-inch audio CDs.

Models

Main article: Mega-CD consoles.

Like the Mega Drive, there were two major revisions of the add-on by Sega and several special combination units.

Mega-CD

The original Mega-CD utilises a CD tray, and sits underneath the Mega Drive (or Mega Drive 2). It is a reasonably large add-on designed to be permanently attached to the console at all times.

Mega-CD 2

A cost-reduced model of the Mega-CD was produced and released around the same period as the cost-reduced Mega Drive 2. In Japan, the system debuted on the 23rd April, 1993[7], with a US release around Summer CES 1993 and August 1993 for Europe[8].

This version sits on the right hand side of the Mega Drive, though continues to act as a new base for the console, and is a top-loading device. Fewer mechanical parts means less is likely to go wrong with a Mega-CD 2, and is designed to look sleeker and more appealing. The Mega-CD 2 is designed primarily with the Mega Drive 2 in mind, however a plastic extension piece was included to add extra support with an original Mega Drive attached.

Mega Drive combos: JVC Wondermega/X'eye, Pioneer LaserActive, Sega Multi-Mega, and Aiwa Mega CD

Main articles: Wondermega, LaserActive, Sega Multi-Mega, Aiwa Mega CD.

Combination Mega Drive/Mega-CD units were developed over the course of the Mega-CD's lifetime. The Wondermega and LaserActive are standalone consoles; the LaserActive also plays LaserDiscs. The Multi-Mega is a portable audio CD player that can play Mega Drive and Mega-CD games when plugged in to wall power and a TV. The Aiwa Mega CD is a Mega Drive/Mega-CD packed into Aiwa's consumer-level portable CD stereos.

Technical specifications

See Sega Mega Drive technical specifications.

The following are upgrades over the Sega Mega Drive technical specifications.

CPU

  • Main CPU: Motorola 68000 16-bit processor running at 12.5 MHz
    • Same as the Mega Drive/Genesis. Acts as a co-processor along with the Genesis CPU.
    • Bus width: 16-bit
    • Instruction set: 16-bit and 32-bit instructions, 16 registers
    • Performance: 2.19 MIPS
  • Co-processor: Motorola 68000 (Mega Drive CPU) running at 7.67 MHz
    • Bus width: 16-bit
    • Performance: 1.34225 MIPS

Graphics

  • GPU graphics processor: Sega 315-5548 Custom ASICMedia:MCD MaintenanceManual Export RevA.pdf[9]
    • Bus width: 32-bit (2x 16-bit)
    • Bus clock rate: 6.25 MHz (25 MB/s bandwidth)
  • Number of simultaneous colors on screen: 64 (default)
    • Using programming tricks, this limit is increased to 128–256 colors via raster effects.
    • 128–256 colors can be displayed on screen using HAM techniques[10]
  • Planes: 5 layers
    • Sega CD FMV layer
    • 3 enhanced Mega Drive layers (sprite layer, 2 tile layers)
    • Mega Drive back screen
  • Full motion video: Video size from 1/4 to full screen, advanced compression scheme, software-based upgrade
    • On-screen colors available in Cinepak and TruVideo modes: 128–256 colors
  • Sprites/Tilemaps: The Mega-CD features enhancement effects such as scaling and rotation, similar to Sega's Super Scaler arcade hardware and that of the "Mode 7" effect employed by the Super NES. While Mode 7 only supports the scaling and rotation of tilemap backgrounds, the Sega CD supports the scaling and rotation of both the sprites and the tilemap backgrounds.[11]
  • DMA transfer rates: 3.467179 MB/s (VRAM), 6.934358 MB/s (CRAM/VSRAM)
    • Transfer rates during active display: 1.625 MB/s (VRAM), 3.25 MB/s (CRAM/VSRAM)
  • Read/Write fillrate: 6.934358 MPixels/s
    • Write fillrate during active display: 3.25 MPixels/s
  • 3D polygon graphics:[12]
    • Vertex transformations: 16,000 vertices/sec[n 1]
    • Polygon transformations: 5000 triangles/sec,[n 2] 4000 quads/sec[n 3]
    • Framebuffer rendering: 256×160, double-buffered, 15–30 FPS[n 4]
    • Flat shading: 3300 polygons/sec (32-pixel triangles),[n 5] 2100 polygons/sec (64-pixel quads)[n 6]
    • Texture mapping: 2000 polygons/sec[n 7]

Sound

The Mega-CD adds 10 sound channels to the 10 provided by the Mega Drive's sound chips.

  • CD Digital Audio
    • 2-channel stereo
    • 44.1 kHz sampling rate
    • 16-bit PCM audio depth
  • Ricoh RF5C164 (315-5476A) PCM chip provides 8 sound channels:Media:MCD MaintenanceManual Export RevA.pdf[9]
    • Sound format: 8-bit sign/magnitude monaural PCM (with "stereo" support by allowing each channel to have different volumes on both left and right channels)
    • Maximum sample rate: 32 kHz
    • PCM audio depth: 16-bit[11]
    • Bus width: 8-bit

Other specifications:

  • 16-bit DAC
  • 8x internal over-sampling digital filter
  • Frequency Range: 20 Hz - 20 KHz
  • Signal-to-Noise Ratio: > 90 dB @ 1K
  • Channel Separation: > 90 dB
  • Input: Mixer cable for Genesis Model 1 compatibility.
  • Output: Stereo RCA connectors.

Memory

Storage

  • 500 MB CD-ROM discs (equivalent to 62 min of audio data)
  • Access time: 800 ms
  • 1/4 screen B/W footage video: 1.5 to 4 hours
  • 1/4 screen color footage: 45 minutes
  • CD-ROM drive transfer rate: 150 Kbytes/s (1x)

(Above specs prior to compression)

Boot ROM

  • Size: 1 Mb (128 KB)
  • Used for games, CD player, CD+G viewing, karaoke (limited to Japanese systems) and regional lockout
  • Region codes: "NA" = North America (NTSC), "EU" = Europe (PAL)
Boot ROM Revisions
Boot ROM Version Machine Download CRC32
0.98 Pioneer LaserActive 0.98 (NA) (info) (88 kB) 8c3e3945
0.98 (Asia) (info) (87 kB) 9f5771d2
1.00 Sega/Mega CD Model 1
Victor WonderMega 1 (Asia)
Sega WonderMega (Asia)
1.00g (Asia, NTSC) (info) (80 kB) 3beb1ac2
1.00l (Asia, NTSC) (info) (84 kB) f18dde5b
1.00o (Asia, NTSC) (info) (80 kB) 1d9756a3
1.00p (Asia, NTSC) (info) (85 kB) 9d2da8f2
1.00s (Asia, NTSC) (info) (84 kB) 79f85384
1.00s (Asia, PAL) (info) (85 kB) 550f30bb
1.00w (Sega WonderMega Bios) (info) (84 kB) d21fe71d
1.00 (NA) (info) (90 kB) e7e3afe2
1.00 (EU) (info) (88 kB) 529ac15a
1.04 Pioneer LaserActive 1.04 (NA) (info) (88 kB) 2ed602d7
1.05 Pioneer LaserActive 1.05 (Asia) (info) (81 kB) b24b919d
1.10 Sega CD Model 1 (minor update) 1.10 (NA) (info) (92 kB) c6d10268
1.11 Mega CD Model 2 (Japan sample/prototype) 1.11 (JP) (info) (86 kB) 4be18ff6
2.00 Sega/Mega CD 2
Victor WonderMega 2 (Asia)
JVC X'Eye (NA)
2.00 (1st NA version) (info) (92 kB) 8af65f58
2.00w (2nd NA version) (info) (92 kB) 9f6f6276
2.00c (Asian version) (info) (85 kB) dd6cc972
2.00 (1st EU version) (info) (90 kB) 0507b590
2.00w (2nd EU version) (info) (90 kB) 4d5cb8da
2.00 (X'Eye) (info) (86 kB) 290f8e33
2.00 (Wondermega) (info) (173 kB) 2b19972f1
2.11 Sega/Mega CD 2, Aiwa CSD G1M (Japan) 2.11w (NA) (info) (93 kB) 2e49d72c
2.11c (JP) (info) (86 kB) 12154531
2.21 Sega Multimega (Europe & Japan), CDX (North America), Linguaphone Education Gear (Japan) 2.21x (MultiMega, EU) (info) (91 kB) aacb851e
2.21x (CDX) (info) (92 kB) d48c44b5

1 The ZIP file contains two dumps, a "good" dump and a "bad" dump. The "bad" dump has an incorrect HINT vector, but is otherwise identical to the "good" dump. The CRC32 listed here is for the "good" dump.

Other

Dimensions: 301mm x 212.5 x 112.5
Weight: 1.4 kg (3.1 lbs)

History

Main article: History of the Sega Mega-CD.

Games

List of games

Main article: List of Mega-CD games.

The five games marked with an asterisk(*) were later released in enhanced form, requiring both the Mega-CD and 32X to be played, and taking advantage of the latter's improved graphics (see Sega Mega-CD 32X).

Launch titles

Japan

North America

United Kingdom

France

Germany

Spain

Italy

Brazil

Magazine articles

Main article: Sega Mega-CD/Magazine articles.

Promotional material

Print advertisements

SegaVisions US 10.pdfSegaVisions US 10.pdf

PDF
Print advert in














Sega Visions (US) #10: "November/December 1992" (1992-xx-xx)
also published in:













  • Electronic Gaming Monthly (US) #44: "March 1993" (1993-xx-xx)[18]

EGM US 041.pdfEGM US 041.pdf

PDF
Print advert in














Electronic Gaming Monthly (US) #41: "December 1992" (1992-xx-xx)
also published in:













  • Electronic Gaming Monthly (US) #43: "February 1993" (199x-xx-xx)[19]

SegaVisions US 15.pdfSegaVisions US 15.pdfSegaVisions US 15.pdfSegaVisions US 15.pdfSegaVisions US 15.pdfSegaVisions US 15.pdfSegaVisions US 15.pdfSegaVisions US 15.pdf

PDF
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Sega Visions (US) #15: "October/November 1993" (1993-xx-xx)

GamePro US 054.pdfGamePro US 054.pdf

PDF
Print advert in














GamePro (US) #54: "January 1994" (199x-xx-xx)
also published in:

GamePlayers US 0710.pdfGamePlayers US 0710.pdf

PDF
Print advert in














Game Players (US) Vol. 7 No. 10 "October 1994" (1994-xx-xx)
also published in:













  • Sega Visions (US) #21: "October/November 1994" (1994-xx-xx)[21]













  • GamePro (US) #64: "November 1994" (1994-xx-xx)[22]













  • Sega Visions (US) #22: "December/January 1994/1995" (1994-xx-xx)[23]

CVG UK 158.pdf

PDF
Print advert in














Computer & Video Games (UK) #158: "January 1995" (1994-12-15)

CVG UK 169.pdf

PDF
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Computer & Video Games (UK) #169: "December 1995" (1995-11-10)
also published in:

MegaForce FR 21.pdfMegaForce FR 21.pdf

PDF
Print advert in














Mega Force (FR) #21: "Octobre 1993" (1993-xx-xx)

SegaMagazin DE 01.pdf

PDF
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Sega Magazin (DE) #1: "September/Oktober 1993" (1993-09-01)

Micromania ES 064.pdfMicromania ES 064.pdf

PDF
Print advert in














Micromanía (ES) Not implemented! (xxxx-xx-xx)

Micromania ES 065.pdfMicromania ES 065.pdf

PDF
Print advert in














Micromanía (ES) Not implemented! (xxxx-xx-xx)
also published in:













  • Micromanía (ES) Not implemented! (xxxx-xx-xx)[26]

Micromania ES 067.pdfMicromania ES 067.pdf

PDF
Print advert in














Micromanía (ES) Not implemented! (xxxx-xx-xx)

Megazone AU 28.pdfMegazone AU 28.pdf

PDF
Print advert in














Megazone (AU) #28: "June 1993" (1993-xx-xx)
also published in:













  • Megazone (AU) #30: "August 1993" (1993-08-04)[27]

Megazone AU 29.pdfMegazone AU 29.pdf

PDF
Print advert in














Megazone (AU) #29: "July 1993" (1993-xx-xx)
also published in:













  • Megazone (AU) #30: "August 1993" (1993-08-04)[28]













  • Megazone (AU) #31: "September 1993" (1993-xx-xx)[29]

Television advertisements

Artwork

Patents

External links

Notes

  1. 767 cycles per vertex
  2. 2301 cycles per triangle polygon
  3. 3068 cycles per quad polygon
  4. 40 KB memory, 614.4 KB/s (15 FPS) to 1.2288 MB/s (30 FPS) bandwidth, 2.383275 CPU cycles per byte VRAM DMA transfer, 1.464285 MHz (15 FPS) to 2.928568 MHz (30 FPS) DMA, 9.571432 MHz (30 FPS) to 11.035715 MHz (15 FPS) remaining for polygons
  5. 32-pixel polygons, 15 FPS, scanline rendering, 250 cycles/scanline per poly, 3301 cycles/poly (4 scanlines)
    • Polygon memory: 40 bytes per polygon, 8.594 KB memory (220 polygons per frame), 132 KB/s bandwidth (3300 polygons/sec)
  6. 64-pixel polygons, 15 FPS, 250 cycles/scanline per poly, 5068 cycles/poly (8 scanlines)
  7. ASIC's sprite/texture scaling and rotation capabilities can be used for texture mapping rasterization
    • CPU cycles: 2 ASIC command cycles per texel, 128 ASIC command cycles per 8×8 texel texture, 77 cycles DMA transfer (32 bytes) per 8×8 texel texture, 5273 cycles (205 texture cycles) per 8×8 texel polygon
    • Polygon/Texture memory: 72 bytes per textured polygon, 9.844 KB memory (140 polygons per frame), 151.2 KB/s bandwidth (2100 polygons/sec)

References

Sega Mega-CD Hardware
 Mega CD Variations   Wondermega | LaserActive | Sega Multi-Mega | CSD-G1M
Misc. Hardware   CD BackUp RAM Cart | Mega-CD Karaoke | Pro CDX
Development Tools SNASM Mega-CD, PsyQ Mega-CD SDK
Cancelled Hardware   Game Genie


Sega Mega Drive
Topics History | List of games | Magazine articles | Blast processing
Hardware Japan | North America | Europe | Brazil | Asia | South Korea | Australia
EZ Games | Heartbeat Personal Trainer | LaserActive | Mega Jet | Mega PC | Mega Play | Mega-Tech System | Nomad | Teradrive | "Consoles on a chip"
Add-Ons Power Base Converter | Mega-CD | 32X (Mega-CD 32X) | Mega Modem | Demo System DS-16
Controllers Control Pad | Six Button Control Pad | 6 Button Arcade Pad | Arcade Power Stick 6B | Konami Justifier | MK-1470
Action Chair | Activator | Arcade Power Stick | Keyboard | MegaFire | Mouse | Mega Stick | Menacer | Remote Arcade System | Ten Key Pad
Accessories 4 Way Play | Cleaning System | Control Pad Extension Cord | Genesis Speakers | Region converter cartridges | Mega Terminal | Miracle Piano Teaching System | Nomad PowerBack | RF Unit (Mega Drive 2) | SCART Cable (Mega Drive 2) | Stereo Audio Video Cable | Team Player | Video Monitor Cable
Network services Sega Channel | Sega Meganet (Sega Game Toshokan | Mega Anser) | Tectoy Mega Net | Telebradesco Residência | XB∀ND
Development tools ERX 308P | ERX 318P | Sprobe
Unreleased Floppy Disk Drive | Mega Play 1010 | Sega VR | Video Jukebox
Sega Home Video Game Systems
83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11
SG-1000 SG-1000 II Mega Drive Mega Drive II
SC-3000 Mega-CD Mega-CD II Genesis 3
Sega Mark III 32X Dreamcast
Master System Master System II
AI Computer Game Gear
Saturn
Pico Beena