Sega genesis specs

Sega genesis specs DEFAULT

October 1988 saw the release of the Sega Mega Drive in Japan after two years of development.  A few months later it was released in the US under the name Genesis.  The Mega Drive's only competitor was NEC's Turbografx-16, however, that didn't last for long as Sega managed to get more and more third party software developers to sign up with them and write quality games for the console.  Golden Axe and After Burner were just some of the hits on the console.  The result was a 16-bit console with top-notch games and a strong lineup of third-party developers.  The Mega Drive was the king of 16-bit consoles!

Then enter the SNES, which had been delayed until 1991 because the NES was still doing good and new games were still being released for it.  The way Sega tackled the potential threat of the SNES was by heavily advertising its console and attractive line-up of quality games.  Sega also played heavily on the SNES's slow processing speed in its favor.  The release of Sonic The Hedgehog in 1992 did wonders for the Mega Drive.  It gave Sega a mascot and an icon to use in its marketing, and also pushed the Mega Drive to its limit by showcasing beautiful graphics and sound coupled with blazing fast gameplay.

Sega developed the Sega Virtual Processor (SVP) with the help of Hitachi in 1994 in answer to the SNES's Super FX chip, allowing games utilizing it to make use of polygons and render graphics in 3D.  It was included on the cartridge's PCB as opposed to on the console's board.  Unfortunately, only one game ever supported the chip: Virtua Racing.

The Mega Drive was discontinued by Sega in 1997, after years of being the best console in the market.  It fought well against the SNES and had games like Mortal Kombat that gave it an image of being a hardcore gamer's machine as opposed to Nintendo's kiddy releases and cut versions of games.  It retailed for $189.

Technical Specs:

CPU: 16-bit Motorolla 68000 (7.68MHz)
Co-processor: Z80 Zilog (4MHz)
Graphics: Dedicated graphics processor
Colors: 512 (64 on screen)
Sprites: 80
Resolution: 320x224 pixels
Sound: 6 channel stereo.  TI 76489 PSG, Yamaha YM 2612 FM chips

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Sega Mega Drive/Hardware comparison

For technical details on the Sega Mega Drive, see Sega Mega Drive/Technical specifications.

This article presents a hardware comparison between the Sega Mega Drive (Genesis) and other rival systems in its time, most notably the SNES. It compares the technical specifications and hardware advantages/disadvantages between the systems.


Main CPU

The Mega Drive's main CPU (central processing unit) is clocked over two times faster than the one in its rival product, the SNES. Sega's Motorola 68000 processor is clocked at 7.67 MHz, compared to the 3.58 MHz clock speed of Nintendo's Ricoh5A22 S-CPU (an adaptation of the 65c816 with additional features). However, the idea of simply comparing CPU clock rates to determine performance, regardless of other characteristics, is commonly known as the megahertz myth. While the S-CPU did run slower in clock cycles per second, it required less clock cycles for most instructions, giving it an overall comparable MIPS (million instructions per second) performance to the 68000. In other words, the 68000's higher clock rate is not the reason the 68000 performs faster than the S-CPU.

The 68000's faster performance essentially comes from having a wider data bus, or higher "bits", than the S-CPU. The 68000 is a hybrid 16/32-bit CPU, whereas the S-CPU is a hybrid 8/16-bit CPU. The 68000 has a wider 32-bit internal data bus (double the S-CPU's 16-bit internal data bus) and a wider 16-bit external data bus (double the S-CPU's 8-bit external data bus). This means that, in a single cycle, the 68000 can process a 32-bit instruction while accessing 16-bit data from memory, whereas the S-CPU in a single cycle can process a 16-bit instruction while only accessing 8-bit data from memory. The 68000 also has a hybrid 16/32-bit instruction set,[1] 16×16-bit multiplier, and 32/16-bit divider, whereas the SNES has a hybrid 8/16-bit instruction set, 8×8-bit multiplier, and 16/8-bit divider. This means that the Mega Drive is essentially a hybrid 16/32-bit system, whereas the SNES is a hybrid 8/16-bit system.[2]

The wider multiplier and divider gives the 68000 a performance advantage for arithmetic. While the 68000 and 5A22 are roughly on-par for arithmetic involving smaller 8-bit numbers (up to 256), the 68000 is faster for arithmetic involving larger 16-bit numbers (up to 65,536) and 32-bit numbers (up to 4 billion). So while both are on-par for basic arithmetic involving smaller numbers, the 68000 is faster for more complex arithmetic involving large numbers or more precision (such as calculating 3D polygons, for example). In addition, the 68000 has faster memory bandwidth (due to having a wider data bus) and more registers. The 68000 also had a shared codebase with arcade games, where the 68000 saw widespread use, allowing more efficient arcade conversions.

Overall, the 68000 is only slightly faster than the S-CPU for most operations, but is significantly faster for some operations, such as arithmetic operations dealing with multiplication or larger 32-bit numbers. On the other hand, the S-CPU has a DMA unit, which the 68000 lacks, though that is because the Mega Drive's DMA unit is located in its VDP graphics processor instead. The 68000 alone does not give the Mega Drive a significant performance advantage, but it's the combination of the 68000 with the VDP's DMA unit, along with faster memory, that gives the system a significant performance advantage over the SNES.

Console Sega Mega Drive[3]Super Nintendo[4][5][6][7]
Main CPUMotorola 68000Ricoh5A22 S-CPU (based on 65c816)
Clock rateNTSC7.670454 MHz 2.684658–3.579545 MHz
PAL7.600489 MHz 2.660171–3.546895 MHz
Bits Data bus width 32-bit internal, 16-bit external 16-bit internal, 8-bit external
Word length16-bit 16-bit
Registers16× 32-bit registers 4× 16-bit registers, 4× 8-bit registers
Instruction set16-bit, 32-bit 8-bit, 16-bit
Instructions per
1.342329 MIPS (NTSC),
1.330085 MIPS (PAL)
1.125–1.5 MIPS (NTSC),
1.114738–1.486318 MIPS (PAL)
Arithmetic logic
ALU(s) 16-bit data ALU,
32-bit address ALU (2× 16-bit ALU)
16-bit ALU
Multiplier 16×16-bit[2]8×8-bit[2]
Divider 32/16-bit[2]16/8-bit[2]
Work RAMMemory 64 KB PSRAM
(16-bit, 5.263157 MHz)
(8-bit, 2.660171–2.684658 MHz)
Bandwidth10.526314 MB/s2.684658 MB/s (NTSC), 2.660171 MB/s (PAL)
CPU access (NTSC) 3.835226 MB/s,[n 1] 62 KB per frame 2.684658 MB/s,[n 2] 43 KB per frame
CPU access (PAL) 3.800244 MB/s,[n 3] 73 KB per frame 2.660171 MB/s,[n 4] 51 KB per frame
Memory 128 KB to 8 MB128 KB to 6 MB
Bandwidth 10–15.340906 MB/s 2.5–3.579545 MB/s
CPU access 3.835226 MB/s (NTSC),
3.800244 MB/s (PAL)
2.684658–3.579545 MB/s (NTSC),
2.660171–3.546895 MB/s (PAL)[n 5]
8-bit arithmetic
(-128 to 256)
Additions (8+8-bit)[n 6]1.7 million adds/sec[8]1.7 million adds/sec[n 7]
Multiplications (8×8-bit) 540,000 multiplies/sec[n 8]440,000 multiplies/sec[n 9]
Divisions (16/8-bit) 200,000 divides/sec[n 10]180,000 divides/sec[n 11]
16-bit arithmetic
(-32,768 to 65,536)
Additions (16+16-bit)[n 6]1.7 million adds/sec[8]1.1 million adds/sec[n 12]
Multiplications (16×16-bit) 120,000 multiplies/sec[8]32,000 multiplies/sec[n 13]
Divisions (16/16-bit) 120,000 divides/sec[8]51,000 divides/sec[n 14]
32-bit arithmetic
(-2 billion to 4 billion)
Additions (32+32-bit)[n 6]880,000 adds/sec[8]100,000 adds/sec[n 15]
Multiplications (32×32-bit) 100,000 multiplies/sec[n 16]17,000 multiplies/sec[n 17]
Divisions (32/16-bit) 120,000 divides/sec[8]20,000 divides/sec[n 18]
3D polygon
geometry calculations
Vertices 10,000 vertices/sec[18]2200 vertices/sec[n 19]
Triangle polygons3300 triangles/sec 700 triangles/sec


The Sega Mega Drive's Yamaha YM7101 VDP graphics processor has a powerful DMA unit that could handle DMA (direct memory access) operations at significantly faster speeds than the SNES. This is sometimes referred to as "blast processing".[1]

The Mega Drive's DMA unit is part of the VDP, which is located on the same Yamaha IC6 integrated circuit as the sound chips.[19] The combination of the VDP's high-speed DMA unit with the 68000 CPU as well as faster memory is essentially what gives the Mega Drive a significant performance advantage over the SNES. In comparison, the Super Nintendo's DMA unit is part of its Ricoh 5A22 S-CPU,[5] while its PPU graphics chips lack DMA. On the other hand, the PPU chips come with more built-in hardware graphics features, such as more colors on screen, larger sprites, and background scaling (Mode 7), most of which the VDP is also capable of with its fast DMA, but requires developers to manually program these features.

The Mega Drive's DMA unit could write to VRAM during active display, VBlank, and HBlank,[20] whereas the SNES CPU's DMA unit could only do so during VBlank and HBlank. The Mega Drive has higher memory bandwidth and is capable of quicker DMA transfer rates, giving it a faster performance than the SNES,[6] and helped give the Mega Drive a higher fillrate, higher gameplay resolution, faster parallax scrolling, fast data blitting, and high frame-rate with many moving objects on screen, and allowed it to display more unique tiles (background and sprite tiles) and large sprites (32×32 and higher) on screen, and quickly transfer more unique tiles and large sprites (16×16 and higher) on screen. The Mega Drive's graphics are also rendered with a packed pixel format, which is more flexible and efficient than the Super Nintendo's planar graphics format (except for Mode 7 which also uses packed pixels).

The Mega Drive's DMA capabilities, higher bandwidth, and packed pixel format, give it more flexibility, allowing the hardware to be programmed in various different ways. Combining the CPU's fast arithmetic with the VDP's fast DMA, it could replicate some of the SNES PPU hardware features with software programming, such as larger 64×64 sprites (combining 32×32 sprites), the scaling and rotation of background planes (like the Sega X Board and Mode 7), and direct color (increasing colors on screen); however, its software approach means that it cannot do Mode 7 as fast as the SNES nor can it display as many colors practically in a game. Other programmable capabilities include mid-frame palette swaps (increasing colors per scanline), bitmapframebuffers, sprite scaling and rotation, and ray casting. The Mega Drive could also playback full motion video (FMV) at a higher quality than the SNES. The base Mega Drive hardware (without needing any cartridge enhancement chips) could also render 3D polygon graphics with a performance almost approaching the SNES's optional Super FX (SFX) cartridge enhancement chip,[21][22] which itself was significantly outperformed by the Mega Drive's optional Sega Virtua Processor (SVP) cartridge enhancement chip.

One aspect of the SNES hardware that the Mega Drive cannot replicate with DMA is its color palette. While DMA programming techniques such as those mentioned above could allow the Mega Drive to match the 256 on-screen color display of the SNES, the Mega Drive cannot come close to the overall 32,768 selectable color palette of the SNES. But when in direct color mode (required for certain types of three-dimensional graphics, such as ray casting and 3D polygons), the SNES and Mega Drive are both on-par in terms of colors, as the SNES cannot use its 32,768 color palette in direct color mode.

Console Sega Mega Drive[3]Super Nintendo[4][5][6][7][23]
clock rate
NTSC53.693175 MHz 21.47727 MHz
PAL53.203424 MHz 21.28137 MHz
Graphics processing unit (GPU)Sega 315‑5313 VDP (Yamaha YM7101)RicohS-PPU (PPU1 & PPU2)
Clock rate NTSC 13.423294 MHz 5.579545 MHz (PPU1), 3.579545 MHz (PPU2)
PAL 13.300856 MHz 5.320343 MHz (PPU1), 3.546895 MHz (PPU2)
GPU cache
Cache 232 bytes
(72 bytes CRAM, 80 bytes VSRAM, 80 bytes spritebuffer)
1056 bytes
(544 bytes PPU1 OAM, 512 bytes PPU2 CGRAM)
Bandwidth26.846588 MB/s (NTSC), 26.601712 MB/s (PAL) PPU1 OAM:
11.15909 MB/s (NTSC), 10.640685 MB/s (PAL)
7.15909 MB/s (NTSC), 7.09379 MB/s (PAL)
Video RAM
Memory 64 KB VRAM (Dual-Port)
(64 KB FPM DRAM, 256 bytes SAM buffer)
Bandwidth 13.423294 MB/s (NTSC), 13.300856 MB/s (PAL) 11.15909 MB/s (NTSC), 10.640685 MB/s (PAL)
PixelsPixel format Packed pixelPlanar (Modes 1-6), packed pixel (Mode 7)
Read fillrate6.650428–6.934358 MPixels/s
(103,912–108,349 tiles/sec)
5.320342–5.369317 MPixels/s
(83,130–83,896 tiles/sec)
Tiles on screen 1808 tiles 1395 tiles (NTSC), 1536 tiles (PAL)
ResolutionOverscan 427×262 (NTSC), 423×312 (PAL) 341×262 (NTSC), 341×312 (PAL)
Gameplay: 256×224 to 320×480 (default 320×224) Gameplay: 256×224 to 256×239 (default 256×224)
Pseudo-hires text: 512×448, 512×478 (half-pixels)
Sprite fillrate 4.90887 MTexels/s (76,701 sprites/sec),
320 texels per scanline
4.282881 MTexels/s (66,920 sprites/sec),
272 texels per scanline
Sprite tiles
on screen
1280 sprite tiles (8×8) 512 sprite tiles (8×8)
Sprite sizes 16 sprites sizes (16 sizes on screen)
(8×8, 8×16, 8×24, 8×32, 16×8, 16×16, 16×24, 16×32,
24×8, 24×16, 24×24, 24×32,
32×8, 32×16, 32×24, 32×32)
4 sprites sizes (2 sizes on screen)
(8x8, 16x16, 32x32, 64x64)
Sprites per
20 sprites (8×8 to 16×16), 13 sprites (24×24),
10 sprites (32×32), 5 sprites (64×64)
32 sprites (8×8), 17 sprites (16×16),
8 sprites (32×32), 4 sprites (64×64)
Sprites on
80 sprites (8×8 to 32×32), 20 sprites (64×64),
5 sprites (128×128)
128 sprites (8×8, 16×16), 69 sprites (32×32),
17 sprites (64×64), 4 sprites (128×128)
Unique sprites
on screen
80 sprites (8×8 to 32×32), 20 sprites (64×64),
5 sprites (128×128)
128 sprites (8×8, 16×16), 32 sprites (32×32),
8 sprites (64×64), 2 sprites (128×128)
Background tiles
on screen
1344–1808 background tiles 256–1024 background tiles
Tilemap planes 2 scrolling planes (1344–1808 tiles),
1 static window plane,
20–32 overlapping scrolling layers per scrolling plane
1–4 planes (256–1024 tiles)
256×256 to 512×512 (2 planes, 1344–1808 tiles),
1024×256 (2 planes, 1344–1424 tiles)
256×256 to 512×512 (1–4 planes, 256–1024 tiles),
1024×1024 (1 plane, 256 tiles)
Parallax scrolling, line scrolling, tile scrolling,
row/column scrolling, overlapping scrolling layers
Parallax scrolling, line scrolling, tile scrolling
(without DMA)
Color palette512 colors (default),
1536 colors (Shadow/Highlight)
32,768 colors
Colors on screen 61–64 (default), 183–192 (Shadow/Highlight) 128–256 (1–2 planes), 128–160 (3 planes),
128 (4 planes)
Colors per tile 16 colors (2 planes) 16 colors (1–2 planes), 8 colors (3 planes),
4 colors (4 planes)
DMA controllerSega 315‑5313 VDP (Yamaha YM7101) DMA unit Ricoh5A22 (CPU) DMA unit
Clock rate NTSC 13.423294 MHz 2.684658–3.579545 MHz
PAL 13.300856 MHz 2.660171–3.546895 MHz
(inactive display)
VRAM: 3.21845 MB/s, 205 bytes per scanline
VDP cache: 6.4369 MB/s, 410 bytes per scanline
NTSC: 2.684658 MB/s, 170.5 bytes per scanline
PAL: 2.660171 MB/s, 170.5 bytes per scanline
During active display
320×224: 708.406 KB/s (NTSC), 1.09701 MB/s (PAL)
320×160: 1.437846 MB/s (NTSC), 1.702026 MB/s (PAL)
256×224: 443.228 KB/s (NTSC), 795.11 KB/s (PAL)
256×192: 763.435 KB/s (NTSC), 1.061548 MB/s (PAL)
During active display
320×224: 1.416813 MB/s (NTSC), 2.194021 MB/s (PAL)
320×160: 2.875692 MB/s (NTSC), 3.404052 MB/s (PAL)
DMA blitting
Write fillrate
(VBlank/inactive display)
6.4369 MPixels/s,
410 pixels (51 tiles) per scanline
5.320342–5.369317 MPixels/s,
341 pixels (42 tiles) per scanline
Write fillrate
(during active display)
1.416813–2.875692 MPixels/s (NTSC),
2.194021–3.404052 MPixels/s (PAL)
886,457 pixels/s (NTSC),
1.59022 MPixels/s (PAL)
Tile blitting per frame
(during active display)
369 tiles (NTSC), 1070 tiles (PAL) 230 tiles (NTSC), 496 tiles (PAL)
per frame
NTSC 80 sprites (8×8 to 16×16), 41 sprites (24×24),
23 sprites (32×32), 5 sprites (64×64)
128 sprites (8×8), 57 sprites (16×16),
14 sprites (32×32), 3 sprites (64×64)
PAL 80 sprites (8×8 to 24×24), 66 sprites (32×32),
16 sprites (64×64), 4 sprites (128×128)
128 sprites (8×8), 124 sprites (16×16),
31 sprites (32×32), 7 sprites (64×64)
Scaling and
Background DMA software rendering Mode 7 hardware rendering
Sprites DMA software rendering SuperFX enhancement chip required
Color DMA Color paletteUp to 4096 colors (bitmap image) 32,768 colors (default),
256–4096 colors (direct color)
on screen
256–512 (direct color), 1536 (scrolling image),
4096 (static image)
256-512 (direct color), 2723 (static image)
Colors per tile 16–256 colors (palette swap),
64–512 colors (direct color)
16–256 colors (direct color)
3D polygon
Flat shading 1800 polygons/sec 400 polygons/sec[n 20]
Texture mapping 1000 polygons/sec 100 polygons/sec[n 21]
Full motion video
Maximum bitrate4.608 Mbps (576 KB/s, 24 KB per frame) 1.773 Mbps (222 KB/s, 18 KB per frame)[32]
Maximum quality 320×224 resolution, 8-bit color 256×224 resolution, 8-bit color[32]


The Mega Drive's audio hardware includes a sound CPU, the ZilogZ80, along with two sound chips, the Yamaha YM2612 and the Sega PSG, both located on the same Sega-Yamaha IC6 integrated circuit as the Yamaha VDP graphics processor, with the PSG located within the VDP itself. The Super Nintendo's audio processing unit, the Sony S-SMP, includes an audio CPU, the Sony SPC700, and a DSP sound chip, the S-DSP.

The Mega Drive's Z80 audio CPU has over three times the clock rate of the Super Nintendo's SPC700 audio CPU. However, the SPC700 requires less cycles per instruction, so the Z80 is only slightly faster for most operations. What gives the Z80 a significant performance advantage, however, is that it has direct memory access to the 68000 address space (in addition to its own internal 8 KB sound RAM), allowing it to stream data directly from the ROMcartridge, whereas the SPC700 only has direct access to its limited 64 KB internal sound RAM (where the main 5A22 S-CPU needs to transfer the audio data). This allows the Mega Drive to stream audio data from the ROM cartridge at a higher speed than the SNES, as well as giving the Z80 more flexibility to be used for non-audio purposes (such as Sega Master System emulation, for example).

The Mega Drive's YM2612 sound chip has a sound output of 53 kHz, higher than the Super Nintendo's S-DSP which has a 32 kHz output, giving the YM2612 a wider frequency range. The S-DSP also uses Gaussian filtering, which eliminates noise by cutting-off the lowest and highest frequencies, at the expense of further limiting the frequency range, creating a muffled sound. The Mega Drive's greater frequency range, on the other hand, provides sharper audio clarity, but with more noise heard at at the highest frequencies, while a lowpass filter reduces noise at the lowest frequencies on both systems (with the Super Nintendo's Gaussian filter further reducing noise at the expense of muffling).

The Mega Drive's sound chips have more sound channels than the Super Nintendo's S-DSP. The S-DSP only supports PCM sampling, whereas the Mega Drive's YM2612 supports both FM synthesis and PCM sampling while the PSG provides additional synthesized channels. Most Mega Drive games primarily used FM synthesis, which requires significantly less data than PCM samples, making FM synthesis much more efficient for memory, storage and bandwidth. The YM2612 was essentially a cut-down version of the FM synthesis chips used in Yamaha synthesizers at the time, allowing the Mega Drive to be used as a cheap synthesizer in addition to limited sampling capabilities, whereas the SNES could only playback pre-recorded samples.

In terms of PCM sampling capabilities, the S-SMP supports 8 PCM channels, whereas the YM2612 only has a single PCM channel, but it can emulate 2-4 PCM channels with software mixing. The S-SMP's PCM sampling is limited to 16-bit 32 kHz quality, slightly higher than the YM2612's PCM sampling which is limited to 8-bit 32 kHz quality. Due to the Z80 having direct access to the ROM cartridge, the YM2612 can stream PCM audio directly from the ROM cartridge, whereas the S-SMP can only access samples from its limited 64 KB sound RAM, relying on the main S-CPU to transfer samples from the ROM cartridge. This allows the YM2612 to stream high-quality PCM audio at a high bitrate without straining the main 68000 CPU (saving most of its bandwidth for graphics or game logic), whereas streaming high-quality PCM audio on the SNES strains the main S-CPU (significantly reducing its bandwidth for graphics or game logic).

The Mega Drive's secondary sound chip, the PSG, can also play PCM samples, by using its three tone channels to make up a single PCM channel. It can play mono samples with up to 44.1 kHz sample rate (at 4-bit depth) or up to 12-bit audio depth (at 11.025 kHz). Some Mega Drive games use the PSG for playing PCM samples, such as After Burner II.[33] However, playing a high-quality 44 kHz sample with the PSG can strain the Z80, whereas playing a 32 kHz sample with the YM2612 uses only a fraction of the Z80's bandwidth. Nevertheless, it is technically possible to use the 68000 CPU to handle PCM playback (1-4 channels) on the YM2612 chip, and the Z80 CPU to handle PCM playback (1 channel) on the PSG chip, for a total of 2-5 PCM channels on the Mega Drive, in addition to 5 FM channels. However, it is worth noting that most Mega Drive games didn't make much use of the system's PCM capabilities, as FM synthesis was much more memory efficient, while PCM sampling also required more complex programming on the Mega Drive.

Console Sega Mega Drive[3]Super Nintendo[4][5][6]
System master
clock rate
NTSC 53.693175 MHz 24.576 MHz
PAL 53.203424 MHz 24.576 MHz
Audio CPU ZilogZ80Sony SPC700
Clock rate NTSC 3.579545 MHz 1.024 MHz
PAL 3.546894 MHz 1.024 MHz
Bits Bus width 8-bit 8-bit
Word length 8-bit 8-bit
Instruction set 8-bit, 16-bit 8-bit, 16-bit
Instructions per
NTSC 0.519034 MIPS 0.44032 MIPS[34]
PAL 0.5143 MIPS 0.44032 MIPS
Sound RAM Memory 8 KB SRAM/XRAM (8-bit, 3.030303 MHz) 64 KB SRAM (8-bit, 1.024 MHz)
Bandwidth 3.030303 MB/s 1.024 MB/s
Memory access Addressable memory 8 KB sound RAM,
64 KB work RAM (32 KB banks),
128 KB to 8 MB cartridge ROM (32 KB banks)
64 KB sound RAM
RAM access bandwidth 1.193182 MB/s (NTSC),
1.182298 MB/s (PAL)[35]
1.024 MB/s
Cartridge ROM
access bandwidth
1.191969 MB/s (NTSC), 1.181096 MB/s (PAL) 128 KB/s (S-CPU)[36]
Sound chip(s) YamahaYM2612, SegaPSG[37]Sony S-DSP
Clock rate NTSC 7.670454 MHz (YM2612), 3.579545 MHz (PSG) 2.048 MHz
PAL 7.600489 MHz (YM2612), 3.546894 MHz (PSG) 2.048 MHz
Sound output Speakers Mono, stereo Mono, stereo, virtual surround sound
Frequency 53.267 kHz (NTSC), 52.781 kHz (PAL) 32 kHz
Sound channels Total channels 11 channels (hardware),
12-14 channels (software mixing)
8 channels
Synthesis channels 11 channels
(6 FM, 1 LFO, 3 square waves, 1 noise)
PCM sample channels 1-2 channels (hardware),
2-5 channels (software mixing)
8 channels
FM synthesisFM channels 6 channels (or 5 channels with PCM) N/A
Operators 24 operators (4 operators per channel)
PCM sampling File formats PCM, DPCM, ADPCM, VGM, XGM, TFM, WAV, MODPCM (16-bit), ADPCM (4-bit),[38]BRR[39]
Streaming bandwidth 1000 KB/s (8000 Kbps) 128 KB/s (1024 Kbps)
Maximum bitrate1200 Kbps (150 KB/s)[n 22]1024 Kbps (128 KB/s)[n 23]
Maximum PCM
sample rate
4-bit depth (mono) 44.1 kHz (1 channel)[41] + 22.05 kHz (2 channels)[40]32 kHz (8 channels)
4-bit depth (stereo) 22.05 kHz (2 channels) 32 kHz (4 channels) / 16 kHz (8 channels)
8-bit depth 32 kHz (1 channel)[40] / 20.5 kHz (2 channels) /
16 kHz (4 channels)[40][41]
12-bit depth 11.025 kHz (1 channel)[41]
16-bit depth (mono) N/A 32 kHz (2 channels) / 16 kHz (4 channels) /
8 kHz (8 channels)
16-bit depth (stereo) N/A 32 kHz (1 channel)[36] / 16 kHz (2 channels) /
8 kHz (4 channels) / 4 kHz (8 channels)

Enhancement chips

Console Sega Mega Drive[3]Super Nintendo Entertainment System
Cartridge enhancement chip Sega Virtua Processor[43]DSP-1[5][44]Super FX[45][46]Super FX 2[45][46]
Co-processor Sega 315-5750
(Samsung SSP1601)
NECµPD77C25Nintendo GSU-1 Nintendo GSU-2
Clock rate 23.01136 MHz 7.647059 MHz[n 24]10.738635 MHz 21.47727 MHz
Cartridge RAMMemory 128 KB (FPM DRAM) 2-32 KB (SRAM)[47]40-72 KB (SRAM) 40-72 KB (SRAM)
Bandwidth 34.679066 MB/s
(16-bit, 18.181818 MHz)
6.666666 MB/s
(8-bit, 6.666666 MHz)[47]
10.738635 MB/s
(8-bit, 10.738635 MHz)[48]
14.285714 MB/s
(8-bit, 14.285714 MHz)[48]
Additions 23,011,360 adds/sec 596,000 adds/sec 10,738,635 adds/sec[n 25]21,477,270 adds/sec
Multiplications 23,011,360 multiplies/sec 294,117 multiplies/sec 2,147,727 multiplies/sec[n 26]4,295,454 multiplies/sec
Divisions 719,105 divides/sec 77,519 divides/sec 335,582 divides/sec[n 27]671,164 divides/sec
Scaling and
Background Hardware rendering Mode 7 Mode 7 Mode 7
SpritesHardware rendering N/A Hardware rendering Hardware rendering
3D polygon
50,000 polys/s 1,900 polys/s[n 28]10,000 polys/s[n 29]20,000 polys/s
20,000 polys/s 940 polys/s[n 30]2000 polys/s[n 31]4000 polys/s
3000 polys/s 660 polys/s[n 32]1000 polys/s[n 33]2000 polys/s

Vs. Amiga

The Mega Drive was generally more powerful than the Amiga. The Mega Drive's 68000 CPU is clocked at 7.6 MHz, while the Amiga's 68000 CPU was clocked at 7.16 MHz (NTSC) or 7.09 MHz (PAL). The Mega Drive displays eighty 15-color sprites at 32×32 pixels each, while the Amiga displays eight 3-color sprites at 8 pixels wide.[50] The Mega Drive displays 61–64 colors standard and 183–192 colors with Shadow/Highlight, while the Amiga displays 2–32 colors standard and 64 colors with EHB. The Mega Drive's VDP can DMAblit 3.21845–6.4 MB/s bandwidth (6.4 MPixels/s fillrate), while the Amiga's Blitter can blit 1.7725–3.58 MB/s (2.363333–4.773333 MPixels/s with 64 colors). During active display, with 64 colors at 60 FPS, the VDP can write 708 KB/s to 2 MB/s (1.4–2 MPixels/s) during 320×224 display, while the Blitter can write 332.5–700 KB/s (443,333–933,333 pixels/s) during 320×200 display.[51] The Mega Drive supports tilemap backgrounds, reducing processing, memory and bandwidth requirements by up to 64 times compared to the Amiga's bitmap backgrounds,[52] giving the Mega Drive an effective tile fillrate of 6–36 MPixels/s. The Mega Drive has a Z80 sound CPU and supports 10 audio channels, while the Amiga lacks a sound CPU and supports 4 audio channels.[50]

Vs. other systems

It was the most powerful console at the time of its release in 1988, surpassing the PC Engine (TurboGrafx-16), and it was not surpassed in power until the Neo Geo in 1990.

Compared to home computers at the time, it was not as powerful as the Japan-exclusive X68000 (released 1987) or FM Towns (released 1989). But the Mega Drive was generally more powerful than Western home computers in the late '80s.


  1. ↑ [16-bit data bus, 7.670454 MHz (NTSC), 4 cycles per word, 16-bit (2 bytes) per word, 2 cycles per byte 16-bit data bus, 7.670454 MHz (NTSC), 4 cycles per word, 16-bit (2 bytes) per word, 2 cycles per byte]
  2. ↑ [8-bit data bus, 2.684658 MHz (NTSC), 1 cycle per byte 8-bit data bus, 2.684658 MHz (NTSC), 1 cycle per byte]
  3. ↑ [16-bit data bus, 7.600489 MHz (PAL), 4 cycles per word, 16-bit (2 bytes) per word, 2 cycles per byte 16-bit data bus, 7.600489 MHz (PAL), 4 cycles per word, 16-bit (2 bytes) per word, 2 cycles per byte]
  4. ↑ [8-bit data bus, 2.660171 MHz (PAL), 1 cycle per byte 8-bit data bus, 2.660171 MHz (PAL), 1 cycle per byte]
  5. ↑ [8-bit data bus, 2.684658–3.579545 MHz (NTSC), 2.660171–3.546895 MHz (PAL), 1 cycle per byte 8-bit data bus, 2.684658–3.579545 MHz (NTSC), 2.660171–3.546895 MHz (PAL), 1 cycle per byte]
  6. [Same performance for subtractions Same performance for subtractions]
  7. ↑ [2 cycles per 8-bit add[9] 2 cycles per 8-bit add[9]]
  8. ↑ [14 cycles per 8×8-bit multiply[10] 14 cycles per 8×8-bit multiply[10]]
  9. ↑ [8 cycles per 8×8-bit multiply[11] 8 cycles per 8×8-bit multiply[11]]
  10. ↑ [38 cycles per 16/8-bit divide[12] 38 cycles per 16/8-bit divide[12]]
  11. ↑ [19 cycles per 16/8-bit divide[5] 19 cycles per 16/8-bit divide[5]]
  12. ↑ [Minimum 3 cycles per 16-bit add[9] Minimum 3 cycles per 16-bit add[9]]
  13. ↑ [38 cycles per 16×8-bit multiply (3 cycles SEP, 7 cycles STA, 3 cycles XBA, 6 cycles STA, 6 cycles STY, 3 cycles REP, 2 cycles LDA, 2 cycles LDY, 6 cycles RTS)[13][9]
    109 cycles per 16×16-bit multiply: 2× 16×8-bit multiplies (38 cycles each), 32-bit add (33 cycles)[14] 38 cycles per 16×8-bit multiply (3 cycles SEP, 7 cycles STA, 3 cycles XBA, 6 cycles STA, 6 cycles STY, 3 cycles REP, 2 cycles LDA, 2 cycles LDY, 6 cycles RTS)[13][9]
    109 cycles per 16×16-bit multiply: 2× 16×8-bit multiplies (38 cycles each), 32-bit add (33 cycles)[14]]
  14. ↑ [70 cycles per 16/16-bit divide (3 cycles STZ, 2 cycles LDY, 2 cycles ASL, 2 cycles BCS, 2 cycles INY, 2 cycles CPY, 4 cycles BNE, 7 cycles ROR, 3 cycles PHA, 2 cycles TXA, 2 cycles SEC, 7 cycles SBC, 4 cycles BCC, 2 cycles TAX, 7 cycles ROL, 4 cycles PLA, 7 cycles LSR, 2 cycles DEY, 6 cycles RTS)[15][9] 70 cycles per 16/16-bit divide (3 cycles STZ, 2 cycles LDY, 2 cycles ASL, 2 cycles BCS, 2 cycles INY, 2 cycles CPY, 4 cycles BNE, 7 cycles ROR, 3 cycles PHA, 2 cycles TXA, 2 cycles SEC, 7 cycles SBC, 4 cycles BCC, 2 cycles TAX, 7 cycles ROL, 4 cycles PLA, 7 cycles LSR, 2 cycles DEY, 6 cycles RTS)[15][9]]
  15. ↑ [33 cycles per 32-bit add (3 cycles REP, 2 cycles CLC, 2 cycles CLD, 8 cycles LDA ADR, 10 cycles 16-bit ADC ADR, 8 cycles STA ADR)[16][9] 33 cycles per 32-bit add (3 cycles REP, 2 cycles CLC, 2 cycles CLD, 8 cycles LDA ADR, 10 cycles 16-bit ADC ADR, 8 cycles STA ADR)[16][9]]
  16. ↑ [70 cycles per 32×32-bit multiply (MULU.L)[17] 70 cycles per 32×32-bit multiply (MULU.L)[17]]
  17. ↑ [209 cycles per 32×32-bit multiply: 2× 16×16-bit multiplies (88 cycles each), 32-bit add (33 cycles)[14] 209 cycles per 32×32-bit multiply: 2× 16×16-bit multiplies (88 cycles each), 32-bit add (33 cycles)[14]]
  18. ↑ [173 cycles per 32/16-bit divide: 2× 16/16-bit divides (70 cycles each), 32-bit add (33 cycles)[14] 173 cycles per 32/16-bit divide: 2× 16/16-bit divides (70 cycles each), 32-bit add (33 cycles)[14]]
  19. ↑ [SNES CPU polygon geometry calculations:
    • 1597 cycles per vertex: 11x 16×16-bit multiplies (109 cycles each), 6x 32-bit adds (33 cycles each), 9x 16-bit adds (3 cycles each), 32/16-bit divide (173 cycles)[14] SNES CPU polygon geometry calculations:
    • 1597 cycles per vertex: 11x 16×16-bit multiplies (109 cycles each), 6x 32-bit adds (33 cycles each), 9x 16-bit adds (3 cycles each), 32/16-bit divide (173 cycles)[14]]
  20. ↑ [SNES CPU polygon rendering:
    Framebuffer rendering: 256×160 framebuffer (double-buffered, 40 KB), 15 FPS (614.4 KB/s), 819.64 kHz framebuffer DMA (1.334 kHz per KB,[24] 30 cycles setup), 30 cycles per DMA setup (4 cycles LDX, 6 cycles STX, 8 cycles LDA, 12 cycles STA)[25][9]
    Polygon rendering: 1.865018 MHz (15 FPS), 4363 cycles per 8×8 pixel polygon
    • 1597 cycles geometry per polygon
    • 496 cycles polygon rendering per polygon: 24 comparison cycles (12 comparisons,[26] 2 cycles per CPY comparison),[9] 7 assignments (6 rasterization assignments,[26] 1 flat shading assignment),[27] 218 multiply cycles (2x 16×16-bit multiplies), 132 add cycles (4x 32-bit adds), 5 broadcasts,[28] 110 cycles DMA access (40 bytes per polygon, 2 cycles per byte, 30 cycles setup)[29]
    • 2270 cycles pixel rendering per 8×8 (64-pixel) polygon: 2112 add cycles (32-bit add per pixel),[30] 158 cycles DMA (1 byte per pixel, 2 cycles per pixel, 30 cycles setup) SNES CPU polygon rendering:

    Framebuffer rendering: 256×160 framebuffer (double-buffered, 40 KB), 15 FPS (614.4 KB/s), 819.64 kHz framebuffer DMA (1.334 kHz per KB,[24] 30 cycles setup), 30 cycles per DMA setup (4 cycles LDX, 6 cycles STX, 8 cycles LDA, 12 cycles STA)[25][9]
    Polygon rendering: 1.865018 MHz (15 FPS), 4363 cycles per 8×8 pixel polygon
    • 1597 cycles geometry per polygon
    • 496 cycles polygon rendering per polygon: 24 comparison cycles (12 comparisons,[26] 2 cycles per CPY comparison),[9] 7 assignments (6 rasterization assignments,[26] 1 flat shading assignment),[27] 218 multiply cycles (2x 16×16-bit multiplies), 132 add cycles (4x 32-bit adds), 5 broadcasts,[28] 110 cycles DMA access (40 bytes per polygon, 2 cycles per byte, 30 cycles setup)[29]
    • 2270 cycles pixel rendering per 8×8 (64-pixel) polygon: 2112 add cycles (32-bit add per pixel),[30] 158 cycles DMA (1 byte per pixel, 2 cycles per pixel, 30 cycles setup)]
  21. ↑ [SNES CPU texture mapping: 17.308 kHz per 8×8 texel polygon (12.945 kHz texture mapping per 8×8 texel polygon)
    • 316 cycles DMA per 8×8 texel texture: 2 block moves, 2 cycles per texel (1 byte per texel), 30 cycles setup
    • 12.629 kHz per 8×8 texel polygon: 73x 32/16-bit divides per polygon (173 cycles each), 1557 vertex divide cycles per polygon (9 divides per polygon), 11.072 kHz texel divides per 8×8 texel polygon (64 divides, 1 divide per texel)[31] SNES CPU texture mapping: 17.308 kHz per 8×8 texel polygon (12.945 kHz texture mapping per 8×8 texel polygon)
    • 316 cycles DMA per 8×8 texel texture: 2 block moves, 2 cycles per texel (1 byte per texel), 30 cycles setup
    • 12.629 kHz per 8×8 texel polygon: 73x 32/16-bit divides per polygon (173 cycles each), 1557 vertex divide cycles per polygon (9 divides per polygon), 11.072 kHz texel divides per 8×8 texel polygon (64 divides, 1 divide per texel)[31]]
  22. ↑ [YM2612 - 128 KB/s (4× 8-bit stereo 16 kHz samples)[40]
    PSG - 22.05 KB/s (4-bit mono 44.1 kHz sample)[41] YM2612 - 128 KB/s (4× 8-bit stereo 16 kHz samples)[40]
    PSG - 22.05 KB/s (4-bit mono 44.1 kHz sample)[41]]
  23. ↑ [16-bit stereo 32 kHz sample[36] 16-bit stereo 32 kHz sample[36]]
  24. ↑ [3.4 microseconds per 26 cycles,[44] 2.136322× CPU clock rate 3.4 microseconds per 26 cycles,[44] 2.136322× CPU clock rate]
  25. ↑ [1 cycle per add[45] 1 cycle per add[45]]
  26. ↑ [5 cycles per 16×16 multiply[45] 5 cycles per 16×16 multiply[45]]
  27. ↑ [32 cycles per 16-bit divide[45] 32 cycles per 16-bit divide[45]]
  28. ↑ [DSP-1 geometry calculations: 3,939 cycles per polygon (80 adds, 111 multiplies, 9 divides),[49] 2.136322 cycles (1 CPU cycle) per add, 26 cycles per 16-bit multiply, 98 cycles per divide[44] DSP-1 geometry calculations: 3,939 cycles per polygon (80 adds, 111 multiplies, 9 divides),[49] 2.136322 cycles (1 CPU cycle) per add, 26 cycles per 16-bit multiply, 98 cycles per divide[44]]
  29. ↑ [Super FX geometry calculations: 923 cycles per polygon (80 adds, 111 multiplies, 9 divides),[49] 1 cycle per add, 5 cycles per 16×16 multiply, 32 cycles per 16-bit divide[45] Super FX geometry calculations: 923 cycles per polygon (80 adds, 111 multiplies, 9 divides),[49] 1 cycle per add, 5 cycles per 16×16 multiply, 32 cycles per 16-bit divide[45]]
  30. ↑ [DSP-1 assisted rendering:
    • CPU framebuffer rendering: 256×192 framebuffer (double-buffered, 48 KB), 15 FPS (737.28 KB/s), 983.562 kHz CPU framebuffer DMA (1.334 kHz per KB, 30 cycles setup), 2.101205 MHz DSP-1 cycles
    • Polygon rendering: 5.545854 MHz (15 FPS) DSP-1 cycles available, 5.869 kHz per 8×8 pixel polygon
    • Geometry per polygon: 3,939 DSP-1 cycles
    • Polygon rendering per polygon: 772 DSP-1 cycles (361 CPU cycles)
    • Pixel rendering per 8×8 pixel polygon: 1,158 DSP-1 cycles (542 CPU cycles) DSP-1 assisted rendering:
    • CPU framebuffer rendering: 256×192 framebuffer (double-buffered, 48 KB), 15 FPS (737.28 KB/s), 983.562 kHz CPU framebuffer DMA (1.334 kHz per KB, 30 cycles setup), 2.101205 MHz DSP-1 cycles
    • Polygon rendering: 5.545854 MHz (15 FPS) DSP-1 cycles available, 5.869 kHz per 8×8 pixel polygon
    • Geometry per polygon: 3,939 DSP-1 cycles
    • Polygon rendering per polygon: 772 DSP-1 cycles (361 CPU cycles)
    • Pixel rendering per 8×8 pixel polygon: 1,158 DSP-1 cycles (542 CPU cycles)]
  31. ↑ [Super FX rendering:
    • Framebuffer rendering: 256×192 framebuffer (double-buffered, 48 KB), 15 FPS (737.28 KB/s), 983.562 kHz CPU framebuffer DMA (1.334 kHz per KB, 30 cycles setup), 2.950686 MHz Super FX cycles
    • Polygon rendering: 7.787949 MHz (15 FPS) Super FX cycles available, 3.632 kHz per 8×8 pixel polygon
    • Geometry per polygon: 923 Super FX cycles
    • Polygon rendering per polygon: 1083 Super FX cycles (361 CPU cycles)
    • Pixel rendering per 8×8 pixel polygon: 1626 Super FX cycles (542 CPU cycles) Super FX rendering:
    • Framebuffer rendering: 256×192 framebuffer (double-buffered, 48 KB), 15 FPS (737.28 KB/s), 983.562 kHz CPU framebuffer DMA (1.334 kHz per KB, 30 cycles setup), 2.950686 MHz Super FX cycles
    • Polygon rendering: 7.787949 MHz (15 FPS) Super FX cycles available, 3.632 kHz per 8×8 pixel polygon
    • Geometry per polygon: 923 Super FX cycles
    • Polygon rendering per polygon: 1083 Super FX cycles (361 CPU cycles)
    • Pixel rendering per 8×8 pixel polygon: 1626 Super FX cycles (542 CPU cycles)]
  32. ↑ [DSP-1 assisted texture mapping: 11.462 kHz per 8×8 texel polygon (7.83 kHz texture mapping per 8×8 texel polygon)
    • 676 DSP-1 cycles (316 CPU cycles) CPU DMA per 8×8 texel texture
    • 7154 divide cycles per 8×8 texel polygon: 73 divides per 8×8 texel polygon, 882 vertex divide cycles per polygon (9 divides per polygon), 6272 texel divide cycles per 8×8 texel polygon (64 divides, 1 divide per texel) DSP-1 assisted texture mapping: 11.462 kHz per 8×8 texel polygon (7.83 kHz texture mapping per 8×8 texel polygon)
    • 676 DSP-1 cycles (316 CPU cycles) CPU DMA per 8×8 texel texture
    • 7154 divide cycles per 8×8 texel polygon: 73 divides per 8×8 texel polygon, 882 vertex divide cycles per polygon (9 divides per polygon), 6272 texel divide cycles per 8×8 texel polygon (64 divides, 1 divide per texel)]
  33. ↑ [Super FX texture mapping: 6.916 kHz per 8×8 texel polygon (3.284 kHz texture mapping per 8×8 texel polygon)
    • 948 Super FX cycles (316 CPU cycles) DMA per 8×8 texel texture
    • 2336 divide cycles per 8×8 texel polygon: 73 divides per 8×8 texel polygon, 288 vertex divide cycles per polygon (9 divides per polygon), 2048 texel divide cycles per 8×8 texel polygon (64 divides, 1 divide per texel) Super FX texture mapping: 6.916 kHz per 8×8 texel polygon (3.284 kHz texture mapping per 8×8 texel polygon)
    • 948 Super FX cycles (316 CPU cycles) DMA per 8×8 texel texture
    • 2336 divide cycles per 8×8 texel polygon: 73 divides per 8×8 texel polygon, 288 vertex divide cycles per polygon (9 divides per polygon), 2048 texel divide cycles per 8×8 texel polygon (64 divides, 1 divide per texel)]


  1. Asian body swap
  2. Kingdom hearts 3 saïx
  3. Wall corner protector strips
  4. Subaru noise when accelerating

Sega Genesis

Video game console

European/Australasian logo
North American logo
The original Japanese Mega Drive
Model 2 Genesis with 6-button controller
  • Top: Original Japanese Mega Drive
  • Bottom: Genesis Model 2
  • Other variations are pictured under Variations below
TypeHome video game console
GenerationFourth generation
Release date
  • JP: October 29, 1988
  • NA: August 14, 1989
  • KOR: August 1990
  • PAL: September 1990
  • BRA: September 1, 1990
  • 1988–1997 (Sega)
  • 1998–1999 (Majesco)
Units sold
  • Sega: 30.75 million
  • Majesco: 1.5 million (projected)
MediaROM cartridge
  • Progressive: 320×224, 256×224 (NTSC) or 320×240, 256×240 (PAL) pixels, 512 color palette, 61 colors on-screen
  • Interlaced: 320×448, 256×448 (NTSC) or 320×480, 256×480 (PAL)
Online services
Best-selling game
Master System[b]
PredecessorMaster System
SuccessorSega Saturn

The Sega Genesis, known as the Mega Drive[c] outside North America, is a 16-bitfourth-generationhome video game console developed and sold by Sega. The Genesis was Sega's third console and the successor to the Master System. Sega released it in 1988 in Japan as the Mega Drive, and in 1989 in North America as the Genesis. In 1990, it was distributed as the Mega Drive by Virgin Mastertronic in Europe, Ozisoft in Australasia, and Tec Toy in Brazil. In South Korea, it was distributed by Samsung as the Super Gam*Boy and later the Super Aladdin Boy.[d] In Russia, it was distributed by Bitman.

Designed by an R&D team supervised by Hideki Sato and Masami Ishikawa, the Genesis was adapted from Sega's System 16 arcade board, centered on a Motorola 68000 processor as the CPU, a Zilog Z80 as a sound controller, and a video system supporting hardware sprites, tiles, and scrolling. It plays a library of more than 900 games on ROM-based cartridges. Several add-ons were released, including a Power Base Converter to play Master System games. It was released in several different versions, some created by third parties. Sega created two network services to support the Genesis: Sega Meganet and Sega Channel.

In Japan, the Mega Drive fared poorly against its two main competitors, Nintendo's Super Famicom and NEC's PC Engine, but it achieved considerable success in North America, Brazil, and Europe. Contributing to its success was its library of arcade gameports, the popularity of Sega's Sonic the Hedgehog series, several popular sports franchises, and aggressive youth marketing that positioned it as the cool console for adolescents. The North American release in 1991 of the Super Famicom, rebranded as the Super Nintendo Entertainment System, triggered a fierce battle for market share in the United States and Europe known as the "console war".[6][7] As this contest drew increasing attention to the video game industry among the general public, the Genesis and several of its highest-profile games attracted significant legal scrutiny on matters involving reverse engineering and video game violence. Controversy surrounding violent games such as Night Trap and Mortal Kombat led Sega to create the Videogame Rating Council, a predecessor to the Entertainment Software Rating Board.

30.75 million first-party Genesis units were sold worldwide. In addition, Tec Toy sold an estimated three million licensed variants in Brazil, Majesco projected it would sell 1.5 million licensed variants of the system in the United States, Bitman sold an unspecified amount in Russia (though outnumbered by counterfeit clones), and smaller numbers were sold by Samsung in South Korea. By the mid-2010s, licensed third-party Genesis rereleases were still being sold by AtGames in North America and Europe. Many games have been re-released in compilations or on online services such as the Nintendo Virtual Console, Xbox Live Arcade, PlayStation Network, and Steam. The Genesis was succeeded in 1994 by the Sega Saturn.


Further information: History of video games


The Japanese Mega Drive logo

In the early 1980s, Sega Enterprises, Inc. – then a subsidiary of Gulf+Western – was one of the top five arcade game manufacturers active in the United States, as company revenues surpassed $200 million between July 1981 and June 1982.[8] A downturn in the arcade business starting in 1982 seriously hurt the company, leading Gulf+Western to sell its North American arcade manufacturing organization and the licensing rights for its arcade games to Bally Manufacturing.[9][10] The company retained Sega's North American R&D operation, as well as its Japanese subsidiary, Sega Enterprises, Ltd. With its arcade business in decline, Sega Enterprises, Ltd. president Hayao Nakayama advocated that the company leverage its hardware expertise to move into the home console market in Japan, which was in its infancy at the time.[11]

Nakayama received permission to proceed with this project, leading to the release of Sega's first home video game system, the SG-1000, in July 1983.[12] While it had sold 160,000 units in Japan, far exceeding Sega's expectations,[13][14] sales at stores were dominated by Nintendo's Famicom which had been released the same day. Sega estimated that the Famicom outsold the SG-1000 by a 10-to-1 margin.[12] The SG-1000 was replaced by the Sega Mark III within two years.[15] In the meantime, Gulf+Western began to divest itself of its non-core businesses after the death of company founder Charles Bluhdorn,[16] so Nakayama and former Sega CEO David Rosen arranged a management buyout of the Japanese subsidiary in 1984 with financial backing from CSK Corporation, a prominent Japanese software company. Nakayama was then installed as CEO of Sega Enterprises, Ltd.[17]

In 1986, Sega redesigned the Mark III for release in North America as the Master System. This was followed by a European release the next year. Although the Master System was a success in Europe, and later in Brazil, it failed to ignite significant interest in the Japanese or North American markets, which, by the mid-to-late 1980s, were both dominated by Nintendo.[18][19][20] With Sega continuing to have difficulty penetrating the home market, Sega's console R&D team, led by Masami Ishikawa and supervised by Hideki Sato,[21] began work on a successor to the Master System almost immediately after that console launched.[22][23]

In 1987, Sega faced another threat to its console business when Japanese computer giant NEC released the PC Engine amid great publicity.[24] To remain competitive against the two more established consumer electronics companies, Ishikawa and his team decided they needed to incorporate a 16-bit microprocessor into their new system to make an impact in the marketplace and once again turned to Sega's strengths in the arcade industry to adapt the successful Sega System 16 arcade board into architecture for a home console.[23][25] The decision to use a Motorola 68000 as the system's main CPU was made late in development, while a Zilog Z80 was used as a secondary CPU to handle the sound due to fears that the load to the main CPU would be too great if it handled both the visuals and the audio.[23] The 68000 chip was expensive and would have driven the retail price of the console up greatly, but Sega was able to negotiate with a distributor for a tenth of its price on an up-front volume order with the promise of more orders pending the console's future success.[12]

The appearance of the Mega Drive was designed by a team led by Mitsushige Shiraiwa that drew inspiration from audiophile equipment and automobiles. Shiraiwa said this more mature look helped to target the Mega Drive to all ages, unlike the Famicom, which was aimed primarily at children.[26] According to Sato, the Japanese design for the Mega Drive was based on the appearance of an audio player, with "16-bit" embossed in a golden metallic veneer to create an impression of power.[14]

The console was announced in the June 1988 issue of Japanese gaming magazine Beep! as the Mark V, but Sega management wanted a stronger name. After reviewing more than 300 proposals, the company settled on "Mega Drive". In North America, the name was changed to "Genesis".[25] Rosen said he insisted on the name as he disliked "Mega Drive" and wanted to represent "a new beginning" for Sega.[27] Sato said some design elements changed, such as the gold-colored "16-bit" wording, because it was believed that the color would be mistaken for yellow. He believes that the changes in design are representative of the differences in values between Japanese and American culture.[14]


The European PAL version of the Mega Drive launched in 1990, later becoming the highest-selling fourth-genconsole in Europe.

Sega released the Mega Drive in Japan on October 29, 1988, though the launch was overshadowed by Nintendo's release of Super Mario Bros. 3 a week earlier. Positive coverage from magazines Famitsu and Beep! helped to establish a following.[25] Within two days of release, the console's initial production run sold out.[28] However, Sega only managed to ship 400,000 units in the first year. In order to increase sales, Sega released various peripherals and games, including an online banking system and answering machine called the Sega Mega Anser.[25] Nevertheless, the Mega Drive was unable to overtake the venerable Famicom[29] and remained a distant third in Japan behind Nintendo's Super Famicom and NEC's PC Engine throughout the 16-bit era.[30]

Sega announced a North American release date for the system on January 9, 1989.[31] At the time, Sega did not possess a North American sales and marketing organization and was distributing its Master System through Tonka. Dissatisfied with Tonka's performance, Sega looked for a new partner to market the Genesis in North America and offered the rights to Atari Corporation, which did not yet have a 16-bit system. David Rosen made the proposal to Atari CEO Jack Tramiel and the president of Atari's Entertainment Electronics Division, Michael Katz. Tramiel declined to acquire the new console, deeming it too expensive, and instead opted to focus on the Atari ST. Sega decided to launch the console through its own Sega of America subsidiary, which executed a limited launch on August 14, 1989, in New York City and Los Angeles. The Genesis was released in the rest of North America later that year.[32]

The European version of the Mega Drive was released in September 1990,[33] at a price of £189.99,[34][35] i.e. $337 (equivalent to $621 in 2020). The release was handled by Virgin Mastertronic, which was later purchased by Sega in 1991 and became Sega of Europe.[36] Games like Space Harrier II, Ghouls 'n Ghosts, Golden Axe,[35]Super Thunder Blade, and The Revenge of Shinobi were available in stores at launch. The console was also bundled with Altered Beast.[34] The Mega Drive and its first batch of games were shown at the 1990 European Computer Entertainment Show (ECES) in Earl's Court.[37] Between July and August 1990, Virgin initially placed their order for 20,000 Mega Drive units. However, the company increased the order by 10,000 units when advanced orders had exceeded expectations, and another 10,000 units was later added following the console's success at the ECES event. The projected number of units to be sold between September and December 1990 had eventually increased to 40,000 units in the United Kingdom alone.[38]

Other companies assisted in distributing the console to various countries worldwide. Ozisoft handled the Mega Drive's launch and marketing in Australia, as it had done before with the Master System.[39] In Brazil, the Mega Drive was released by Tectoy in 1990,[40] only a year after the Brazilian release of the Master System. Tectoy produced games exclusively for the Brazilian market, and brought the Sega Meganet online service there in 1995.[41]Samsung handled sales and distribution in Korea, where it was named Super Gam*Boy and retained the Mega Drive logo alongside the Samsung name.[42] It was later renamed Super Aladdin Boy.[43] In India, Sega entered a distribution deal with Shaw Wallace in April 1994[44] in order to circumvent an 80% import tariff, with each unit selling for INR₹18,000.[45][46]

In Russia, Sega officially licensed the console to local distributor Bitman in 1995. That year, the video game console market generated between $200,000,000 (equivalent to $340,000,000 in 2020) and $250,000,000 (equivalent to $425,000,000 in 2020) in Russia, with Sega accounting for half of all console sales in the country. However, only about 35% of the sales were official Sega units distributed by Bitman, while the rest were unofficial counterfeit clones.[47][48]

North American sales and marketing

For the North American market, former Atari Corporation Entertainment Electronics Division president and new Sega of America CEO Michael Katz instituted a two-part approach to build sales. The first part involved a marketing campaign to challenge Nintendo head-on and emphasize the more arcade-like experience available on the Genesis,[49] with slogans including "Genesis does what Nintendon't".[25] Since Nintendo owned the console rights to most arcade games of the time, the second part involved creating a library of recognizable games which used the names and likenesses of celebrities and athletes, such as Pat Riley Basketball, Arnold Palmer Tournament Golf, James 'Buster' Douglas Knockout Boxing, Joe Montana Football, Tommy Lasorda Baseball, Mario Lemieux Hockey, and Michael Jackson's Moonwalker.[24][50] Nonetheless, Sega struggled to overcome Nintendo's presence in consumers' homes.[51] Tasked by Nakayama to sell one million units within the first year, Katz and Sega of America sold only 500,000.[25] At the Winter Consumer Electronics Show (Winter CES) in January 1990, the Sega Genesis demonstrated a strong line-up of games which received a positive reception for approaching arcade-quality graphics and gameplay as well as for providing non-arcade experiences such as Phantasy Star II.[52]

In mid-1990, Nakayama hired Tom Kalinske to replace Katz as CEO of Sega of America. Although Kalinske knew little about the video game market, he surrounded himself with industry-savvy advisors. A believer in the razor and blades model, he developed a four-point plan: cut the price of the console, create an American team to develop games targeted at the American market, expand the aggressive advertising campaigns, and replace the bundled game Altered Beast with a new game, Sonic the Hedgehog.[51] The Japanese board of directors initially disapproved of the plan,[53] but all four points were approved by Nakayama, who told Kalinske, "I hired you to make the decisions for Europe and the Americas, so go ahead and do it."[25] Critics praised Sonic as one of the greatest games yet made, and Genesis sales increased as customers who had been waiting for the release of the international version of Nintendo's Super Famicom, the Super Nintendo Entertainment System (SNES), decided to purchase a Genesis instead.[51] The SNES debuted against an established competitor, while NEC's TurboGrafx-16 failed to gain traction, and NEC soon pulled out of the market.[54] In large part due to the popularity of Sonic the Hedgehog, the Genesis outsold the SNES in the United States nearly two to one during the 1991 holiday season. Sega controlled 65% of the 16-bitconsole market in January 1992, the first time Nintendo had not been the console leader since 1985.[55]

The Genesis outsold the SNES for four consecutive Christmas seasons[56] due to its two-year lead, lower price point, and larger game library compared to the SNES at its release.[57] Sega had ten games for every game on SNES, and while the SNES had an exclusive version of Final Fight, one of Sega's internal development teams created Streets of Rage, which had bigger levels, tougher enemies, and a well-regarded soundtrack.[57]ASCII Entertainment reported in early 1993 that Genesis had 250 games versus 75 for the SNES, but limited shelf space meant that stores typically offered 100 Genesis and 50 SNES games. The NES was still the leader, with 300 games and 100 on shelves.[58]

Sega's advertising positioned the Genesis as the cooler console,[57] and coined the term blast processing, an obscure and unused graphics programming method, to suggest that its processing capabilities were far greater than those of the SNES.[59][60] A Sony focus group found that teenage boys would not admit to owning an SNES rather than a Genesis.[61] With the Genesis often outselling the SNES at a ratio of 2:1,[62] Nintendo and Sega focused heavily on impression management of the market, even going to the point of deception; Nintendo claimed it had sold more consoles in 1991 than it actually had, and forecasted it would sell 6 million consoles by the end of 1992, while its actual U.S. install base at the end of 1992 was only just more than 4 million units.[63] Due to these tactics, it was difficult to ascertain a clear leader in market share for several years at a time, with Nintendo's dollar share of the U.S. 16-bit market dipping down from 60% at the end of 1992 to 37% at the end of 1993,[64] Sega claiming 55% of all 16-bit hardware sales during 1994,[65] and Donkey Kong Country helping the SNES to outsell the Genesis from 1995 through 1997.[56][66][67][68][69] According to a 2004 study of NPD sales data, the Genesis maintained its lead over the Super NES in the American 16-bit console market.[70] However, according to a 2014 Wedbush Securities report based on revised NPD sales data, the SNES outsold the Genesis in the U.S. market by 2 million units.[71]

Electronic Arts

To compete with Nintendo, Sega was more open to new types of games, but still tightly controlled the approval process for third-party games and charged high prices for cartridge manufacturing.[72] American third-party publisher Electronic Arts (EA) sought a better deal, but had met resistance from Sega.[73] They decided to reverse-engineer the Genesis, using a clean-room method similar to the method Phoenix Technologies had used to reverse-engineer the IBM Personal ComputerBIOS around 1984.[74]

The process began in 1989, led by Steve Hayes and Jim Nitchals.[75] They created a controlled room in EA headquarters nicknamed "Chernobyl", to which only one person was allowed access, Mike Schwartz. Schwartz reviewed Sega's copyrighted development manuals and tools, studied the Genesis hardware and games, and wrote original documentation that summarized his findings. The process took him about a month.[73] His work was reviewed by EA's lawyers before being disseminated to Hayes and Nitchals to verify its originality, and subsequently to the rest of the developers to let them build games.[74] After a few months, EA began developing for the Genesis in earnest.[73] EA founder Trip Hawkins confronted Nakayama the day before the 1990 Consumer Electronics Show (CES), informing him that EA had the ability to run its own licensing program if Sega refused to meet its demands. Sega relented, and the next day EA's upcoming Genesis games were showcased at CES.[73]

EA signed what Hawkins described as "a very unusual and much more enlightened license agreement" with Sega in June 1990: "Among other things, we had the right to make as many titles as we wanted. We could approve our own titles ... the royalty rates were a lot more reasonable. We also had more direct control over manufacturing."[75] After the deal was in place, EA chief creative officer Bing Gordon learned that "we hadn't figured out all the workarounds" and "Sega still had the ability to lock us out ... It just would have been a public relations fiasco."[73] EA released its first Genesis games, Populous and Budokan: The Martial Spirit, within the month.[75] The first Genesis version of EA's John Madden Football arrived before the end of 1990,[75] and became what Gordon called a "killer app".[73] Taking advantage of the licensing agreement, Gordon and EA's vice president of marketing services Nancy Fong created a visual identifier for EA's Genesis cartridges: a yellow tab molded into the cartridge casing.[73]

Sonic the Hedgehog

Main article: Sonic the Hedgehog (character)

Sega held a company-wide contest to create a mascot character to compete with Nintendo's Mario series. The winning submission was a blue hedgehog with red shoes, Sonic, created by Naoto Ohshima, spawning one of the best-selling video game franchises in history.[78] The gameplay of Sonic the Hedgehog originated with a tech demo created by Yuji Naka, who had developed a prototype platform game that involved a fast-moving character rolling in a ball through a long winding tube. This concept was developed with Ohshima's character design and levels conceived by designer Hirokazu Yasuhara.[79]

Although Katz and Sega of America's marketing experts disliked Sonic, certain that it would not catch on with American children,[24][80] Kalinske's strategy to place Sonic the Hedgehog as the pack-in game paid off.[6][81]Sonic the Hedgehog greatly increased the popularity of the Genesis in North America,[60] and the bundle is credited with helping Sega gain 65% of the market share against Nintendo.[1] Similarly in Europe, Sega had captured a 65% share of the European console market,[82] where the Mega Drive maintained its lead over the SNES through 1994.[83]

Trademark Security System and Sega v. Accolade

Main article: Sega v. Accolade

After the release of the Genesis in 1989, video game publisher Accolade began exploring options to release some of their PC games on the console. At the time, Sega had a licensing deal in place for third-party developers that increased the costs to the developer. According to Accolade co-founder Alan Miller, "One pays them between $10 and $15 per cartridge on top of the real hardware manufacturing costs, so it about doubles the cost of goods to the independent publisher."[84] To get around licensing, Accolade chose to seek an alternative way to bring their games to the Genesis. It did so by purchasing one in order to decompile the executable code of three Genesis games. Such information was used to program their new Genesis cartridges in a way that would allow them to disable the security lockouts on the Genesis that prevented unlicensed games from being played.[85][86] This strategy was used successfully to bring Ishido: The Way of Stones to the Genesis in 1990.[87] To do so, Accolade had copied Sega's copyrighted game code multiple times in order to reverse engineer the software of Sega's licensed Genesis games.[88][89]

An edition of the original model of the Genesis, known as the Genesis III, was the model at the center of Sega v. Accoladefor its incorporation of the Trademark Security System (TMSS).

As a result of piracy in some countries and unlicensed development issues, Sega incorporated a technical protection mechanism into a new edition of the Genesis released in 1990, referred to as the Genesis III. This new variation of the Genesis included a code known as the Trademark Security System (TMSS), which, when a game cartridge was inserted, would check for the presence of the string "SEGA" at a particular point in the memory contained in the cartridge. If the string was present, the console would run the game, and would briefly display the message: "Produced by or under license from Sega Enterprises, Ltd."[85] This system had a twofold effect: it added extra protection against unlicensed developers and software piracy and forced the Sega trademark to display when the game was powered up, making a lawsuit for trademark infringement possible if unlicensed software were to be developed.[86][89] Accolade learned of this development at the Winter Consumer Electronics Show in January 1991, where Sega showed the new Genesis III and demonstrated it screening and rejecting an Ishido game cartridge.[86] With more games planned for the following year, Accolade successfully identified the TMSS file. It later added this file to the games HardBall!, Star Control, Mike Ditka Power Football, and Turrican.[86]

In response to the creation of these unlicensed games, Sega filed suit against Accolade in the United States District Court for the Northern District of California, on charges of trademark infringement, unfair competition, and copyright infringement. In response, Accolade filed a counterclaim for falsifying the source of its games by displaying the Sega trademark when the game was powered up.[88][90] Although the district court initially ruled for Sega and issued an injunction preventing Accolade from continuing to reverse engineer the Genesis, Accolade appealed the verdict to the United States Court of Appeals for the Ninth Circuit.[91]

As a result of the appeal, the Ninth Circuit overturned the district court's verdict and ruled that Accolade's decompilation of the Sega software constituted fair use.[92] The court's written opinion followed on October 20, 1992, and noted that the use of the software was non-exploitative, although commercial.[85][93] Further, the court found that the trademark infringement, being required by the TMSS for a Genesis game to run on the system, had been inadvertently triggered by a fair use act and was the fault of Sega for having caused false labeling.[85] Ultimately, Sega and Accolade settled the case on April 30, 1993. As a part of this settlement, Accolade became an official licensee of Sega, and later developed and released Barkley Shut Up and Jam! while under license.[94] The terms of the licensing, including whether or not any special arrangements or discounts were made to Accolade, were not released to the public.[95] The financial terms of the settlement were also not disclosed, although both companies agreed to pay their own legal costs.[96]

Congressional hearings on video game violence

Main articles: Videogame Rating Council and 1993 congressional hearings on video games

VRC MA-13 rating, as applied to Mortal Kombatfor the Genesis

In 1993, the American media began to focus on the mature content of certain video games. Games such as Night Trap for the Sega CD, an add-on, received unprecedented scrutiny. Issues about Night Trap were brought up in the United Kingdom, with former Sega of Europe development director Mike Brogan noting that "Night Trap got Sega an awful lot of publicity ... it was also cited in UK Parliament for being classified as '15' due to its use of real actors."[97] This came at a time when Sega was capitalizing on its image as an edgy company with attitude, and this only reinforced that image.[29] By far the year's most controversial game was Midway's Mortal Kombat, ported to the Genesis and SNES by Acclaim Entertainment. In response to public outcry over the game's graphic violence, Nintendo decided to replace the blood in the game with "sweat" and the arcade's gruesome "fatalities" with less violent finishing moves.[98] Sega took a different approach, instituting America's first video game ratings system, the Videogame Rating Council (VRC), for all its current systems. Ratings ranged from the family-friendly GA rating to the more mature rating of MA-13, and the adults-only rating of MA-17.[98] With the rating system in place, Sega released its version of Mortal Kombat, appearing to have removed all the blood and sweat effects and toning down the finishing moves even more than in the SNES version. However, all the arcade's blood and uncensored finishing moves could be enabled by entering a "Blood Code". This technicality allowed Sega to release the game with a relatively low MA-13 rating.[99] Meanwhile, the tamer SNES version shipped without a rating.[99]

The Genesis version of Mortal Kombat was well-received by gaming press, as well as fans, outselling the SNES version three- or four-to-one,[98][100][101] while Nintendo was criticized for censoring the SNES version.[99] Executive vice president of Nintendo of America Howard Lincoln was quick to point out at the hearings that Night Trap had no such rating, saying to Senator Joe Lieberman:

Furthermore, I can't let you sit here and buy this nonsense that this Sega Night Trap game was somehow only meant for adults. The fact of the matter is this is a copy of the packaging. There was no rating on this game at all when the game was introduced. Small children bought this at Toys "R" Us, and he knows that as well as I do. When they started getting heat about this game, then they adopted the rating system and put ratings on it.[98]

In response, Sega of America vice president Bill White showed a videotape of violent video games on the SNES and stressed the importance of rating video games. At the end of the hearing, Lieberman called for another hearing in February 1994 to check on progress toward a rating system for video game violence.[98]

As a result of the congressional hearings, Night Trap started to generate more sales and released ports to the PC, Sega 32X, and 3DO. According to Digital Pictures founder Tom Zito, "You know, I sold 50,000 units of Night Trap a week after those hearings."[98] Although experiencing increased sales, Sega decided to recall Night Trap and re-release it with revisions in 1994 due to the congressional hearings.[102] After the close of these hearings, video game manufacturers came together to establish the rating system that Lieberman had called for. Initially, Sega proposed the universal adoption of its system, but after objections by Nintendo and others, Sega took a role in forming a new one. This became the Entertainment Software Rating Board, an independent organization that received praise from Lieberman.[98] With this new rating system in place for the 1994 holiday season, Nintendo decided its censorship policies were no longer needed, and the SNES port of Mortal Kombat II was released uncensored.[99]

32-bit era and beyond

Sega released two add-ons to increase the Genesis capabilities: a CD peripheral, the Sega CD (Mega-CD outside North America and Brazil), and a 32-bit peripheral, the Sega 32X.[81] Worldwide, Sega sold 2.24 million Sega CD units[103] and 800,000 32X units.[104]

Following the launch of the next-generation 32-bit Sony PlayStation and Sega Saturn, sales of 16-bit hardware and software continued to account for 64% of the video game market in 1995.[105] Sega underestimated the continued popularity of the Genesis and did not have the inventory to meet demand.[105][106] Sega captured 43% of the dollar share of the U.S. video game market and claimed to have sold more than two million Genesis units in 1995, while Genesis software such as Vectorman remained successful, but Kalinske estimated that "we could have sold another 300,000 Genesis systems in the November/December timeframe".[106] Nakayama's decision to focus on the Saturn, based on the systems' relative performance in Japan, has been cited as the major contributing factor in this miscalculation.[105] By contrast, Nintendo concentrated on the 16-bit home console market, as well as its successful handheld, the Game Boy, and took in 42% of the video game market dollar share without launching a 32-bit console.[105] Following tensions with Sega Enterprises, Ltd. over its focus on the Saturn, Kalinske, who oversaw the rise of the Genesis in 1991, grew uninterested in the business and resigned in mid-1996.[107]

Sega sold 30.75 million Genesis units worldwide.[108] Of these, 3.58 million were sold in Japan,[103] and sales in Europe and the U.S. are roughly estimated at 8 million[109][110] and 18–18.5 million as of June 1997 (at which time Sega was no longer manufacturing the system) respectively.[69][71][111] In 1998, Sega licensed the Genesis to Majesco Entertainment to rerelease it in North America. Majesco began reselling millions of unsold cartridges at a budget price, together with 150,000 units of the second model of the Genesis.[69] It released the Genesis 3,[112] projecting to sell 1.5 million units of the console by the end of 1998.[69] Tectoy continues to sell emulated variants of the original hardware and has sold an estimated 3 million units in Brazil.[113][114]

Technical specifications

The main microprocessor is a 16/32-bit Motorola 68000CPU clocked at 7.6 MHz.[115] An 8-bit Zilog Z80 processor controls the sound hardware and provides backward compatibility with the Master System. The Genesis has 64 kB of RAM, 64 kB of video RAM and 8 kB of audio RAM.[116] It can display up to 61 colors[117] at once from a palette of 512. The games are in ROM cartridge format and inserted in the top.[118]

The Genesis produces sound using a Texas Instruments SN76489PSG, integrated with the Video Display Processor (VDP), and a Yamaha YM2612FM synthesizer chip. The Z80 processor is primarily used to control both sound chips to produce stereo music and sound effects. Most revisions of the original Genesis contain a discrete YM2612 and a separate YM7101 VDP; in a later revision, the chips were integrated into a single custom ASIC (FC1004).[118]

The back of the model 1 console provides a radio frequency output port (designed for use with antenna and cable systems) and a specialized 8-pin DIN port, which both provide video and audio output. Both outputs produce monophonic sound; a headphone jack on the front of the console produces stereo sound.[119] On the model 2, the DIN port, radio frequency output port, and headphone jack are replaced by a 9-pin mini-DIN port on the back for composite video, RGB and stereo sound, and the standard RF switch.[120] Earlier model 1 consoles have a 9-pin extension port. An edge connector on the bottom right of the console can be connected to a peripheral.[121]


Genesis six-button controller

The standard controller features a rounded shape, a directional pad, three main buttons, and a "start" button. In 1993, Sega released a slightly smaller pad with three additional face buttons, similar to the design of buttons on some popular arcade fighting games such as Street Fighter II. Sega also released a wireless revision of the six-button controller, the Remote Arcade Pad.[122]

The system is backward compatible with the Master System. The first peripheral released, the Power Base Converter (Master System Converter in Europe), allows Master System games to be played. It's designed for the Model 1. It will work with the Model 2, but the shell does block the power and ac ports, so the converter will either to have its shell modified or a pass thru adaptor needs to be used. The converter doesn't work with the Model 3 or the Nomad[123] A second model, the Master System Converter 2, was released only in Europe for use with the Mega Drive II. It will still work with NTSC and PAL Model 1 and 2 consoles, though the Model 3 and Nomad still don't work with it.[122]

Other peripherals were released to add functionality. The Menacer is a wireless, infrared light gun peripheral used with compatible games.[123] Other third parties created light gun peripherals for the Genesis, such as the American Laser Games Pistol and the Konami Justifier. Released for art creation software, the Sega Mega Mouse features three buttons and is only compatible with a few games, such as Eye of the Beholder. A foam-covered bat called the BatterUP and the TeeVGolf golf club were released for both the Genesis and SNES.[122]

Sega Power Base Converter on a model 1 Genesis

In November 1993, Sega released the Sega Activator, an octagonal device that lies flat on the floor and was designed to translate the player's physical movements into game inputs.[122][124] Several high-profile games, including Mortal Kombat and Street Fighter II: Special Champion Edition, were adapted to support the peripheral. The device was a commercial failure, due mainly to its inaccuracy and its high price point.[122][125]IGN editor Craig Harris ranked the Sega Activator the third worst video game controller ever made.[126]

Both EA and Sega released multitaps to allow more than the standard two players to play at once. Initially, EA's version, the 4 Way Play, and Sega's adapter, the Team Player, only supported each publisher's games. In response to complaints about this, Sega publicly stated, "We have been working hard to resolve this problem since we learned of it", and that a new Team Player which would work with all multitap games for the console would be released shortly.[127] Later games were created to work on both the 4 Way Play and Team Player.[122]Codemasters also developed the J-Cart system, providing two extra ports on the cartridge itself, although the technology came late in the console's life and is only featured on a few games.[128] Sega planned to release a steering wheel peripheral in 1994, and the Genesis version of Virtua Racing was advertised as being "steering wheel compatible", but the peripheral was cancelled.[129]

Network services

Sega Mega Modem peripheral, which allowed access to the Sega Meganetservice

In its first foray into online gaming, Sega created Sega Meganet, which debuted in Japan on November 3, 1990. Operating through a cartridge and a peripheral called the "Mega Modem", this allowed Mega Drive players to play a total of seventeen games online. A North American version, dubbed "Tele-Genesis", was announced at the Winter Consumer Electronics Show (Winter CES) in January 1990 but never released,[130][52] though a version was operated in Brazil starting in 1995.[41] Another phone-based system, the Mega Anser, turned the Japanese Mega Drive into an online banking terminal.[25]

In 1994, Sega started the Sega Channel, a game distribution system using cable television services Time Warner Cable and TCI. Using a special peripheral, Genesis players could download a game from a library of fifty each month and demos for upcoming releases. Games were downloaded to internal memory and deleted when the console was powered off. The Sega Channel reached 250,000 subscribers at its peak and ran until July 31, 1998, well past the release of the Sega Saturn.[130]

In an effort to compete with Sega, third-party developer Catapult Entertainment created the XBAND, a peripheral which allowed Genesis players to engage in online competitive gaming. Using telephone services to share data, XBAND was initially offered in five U.S. cities in November 1994. The following year, the service was extended to the SNES, and Catapult teamed up with Blockbuster Video to market the service, but as interest in the service waned, it was discontinued in April 1997.[131]


See also: List of Sega Genesis games

The Genesis library was initially modest, but eventually grew to contain games to appeal to all types of players. The initial pack-in game was Altered Beast, which was later replaced with Sonic the Hedgehog in 1991.[25] Top sellers included Sonic the Hedgehog, its sequel Sonic the Hedgehog 2, and Disney's Aladdin.[132] During development for the console, Sega Enterprises focused on developing action games, while Sega of America was tasked with developing sports games. A large part of the appeal of the Genesis library during the console's lifetime was the arcade-based experience of its games, as well as more difficult entries such as Ecco the Dolphin, and sports games such as Joe Montana Football.[25] Compared to its competition, Sega advertised to an older audience by hosting more mature games, including the uncensored version of Mortal Kombat.[25]

Notably, the arcade hit Street Fighter II by Capcom initially skipped the Genesis, instead only being released on the SNES. However, as the Genesis continued to grow in popularity, Capcom eventually ported a version of Street Fighter II to the system known as Street Fighter II: Champion Edition,[133] that would go on to sell over a million copies.[134] One of the biggest third-party companies to support the Genesis early on was Electronic Arts. Trip Hawkins, founder and then president of EA, believed the faster drawing speed of the Genesis made it more suitable for sport games than the SNES, and credits EA's success on the Genesis for helping catapult the EA Sports brand.[135] Another third-party blockbuster for the system was the port of the original Mortal Kombat. Although the arcade game was released on the SNES and Genesis simultaneously, the two ports were not identical. The SNES version looked closer to the arcade game, but the Genesis version allowed players to bypass censorship, helping make it more popular.[136] In 1997, Sega of America claimed the Genesis had a software attach rate of 16 games sold per console, double that of the SNES.[137]

Sega Virtua Processor

The graphics produced by the Sega Virtua Processor are comparable to those of Nintendo's Super FXchip.[138]

The Super NES can have enhancement chips inside each cartridge to produce more advanced graphics; for example, the launch game Pilotwings (1990) contains a digital signal processor. Later, the Super FX chip was designed to offload complex rendering tasks from the main CPU. It was first used in Star Fox (1993) for real-time 3D polygons, and Super Mario World 2: Yoshi's Island (1995) demonstrates rotation, scaling, and stretching of individual sprites and manipulates large areas of the screen.[138]

Sega had produced such effects on its arcade platforms, and adapted some to the home console by developing the Sega Virtua Processor (SVP). Based on a Samsung digital signal processor core, this chip enables the Genesis to render polygons in real time and provides an "Axis Transformation" unit that handles scaling and rotation. Virtua Racing (1992) is the only game released with this chip and the only Genesis cartridge with any enhancement chip, running at a significantly higher and more stable frame rate than filled polygon games on the SNES.[138] The chip drastically increased the cost of the cartridge, and at US$100 (equivalent to $180 in 2020), Virtua Racing is the most expensive Genesis cartridge ever produced. Two other games, Virtua Fighter and Daytona USA, were planned for the SVP chip, but were instead moved into the Saturn's launch line-up.[138] Sega planned to sell the SVP chip as a separate upgrade module for the Genesis,[139][140] but it was canceled.[138]


In addition to accessories such as the Power Base Converter, the Genesis supports two add-ons that each support their own game libraries. The first is the Sega CD (known as the Mega-CD in all regions except for North America), a compact disc-based peripheral that can play its library of games in CD-ROM format.[141] The second is the Sega 32X, a 32-bit peripheral which uses ROM cartridges and serves as a pass-through for Genesis games.[142] Sega produced a custom power strip to fit the peripherals' large AC adapters.[143] Both add-ons were officially discontinued in 1996.[67][141][142]

Sega CD

Main articles: Sega CD and List of Sega CD games

By 1991, compact discs had gained in popularity as a data storage device for music and software. PCs and video game companies had started to make use of this technology. NEC had been the first to include CD technology in a game console with the release of the TurboGrafx-CD add-on, and Nintendo was making plans to develop its own CD peripheral as well. Seeing the opportunity to gain an advantage over its rivals, Sega partnered with JVC to develop a CD-ROM add-on for the Genesis.[7][144][145] Sega launched the Mega-CD in Japan[7] on December 1, 1991, initially retailing at JP¥49,800.[146] The CD add-on was launched in North America on October 15, 1992, as the Sega CD, with a retail price of US$299;[7] it was released in Europe as the Mega-CD in 1993.[146] In addition to greatly expanding the potential size of its games, this add-on unit upgraded the graphics and sound capabilities by adding a second, more powerful processor, more system memory, and hardware-based scaling and rotation similar to that found in Sega's arcade games.[7][147] It provided battery-backed storage RAM to allow games to save high scores, configuration data, and game progress.[144]

Shortly after its launch in North America, Sega began shipping the Sega CD with the pack-in game Sewer Shark, a full motion video (FMV) game developed by Digital Pictures, a company that became an important partner for Sega.[7] Touting the benefits of the CD's comparatively vast storage space, Sega and its third-party developers produced a number of games for the add-on that include digital video in their gameplay or as bonus content, as well as re-releasing several cartridge-based games with high-fidelity audio tracks.[141][144] In 1993, Sega released the Sega CD 2, a smaller and lighter version of the add-on designed for the Genesis II, at a reduced price compared to the original.[141] A limited number of games were later developed that use both the Sega CD and the Sega 32X add-ons.[148]

The Mega-CD sold only 100,000 units during its first year in Japan, falling well below expectations. Although many consumers blamed its high launch price, it also suffered from a tiny software library; only two games were available at launch. This was due in part to the long delay before Sega made its software development kit available to third-party developers.[146] Sales were higher in North America and Europe, although the novelty of FMV and CD-enhanced games quickly wore off, as many later games were met with lukewarm or negative reviews. In 1995, Sega announced a shift in focus to its new console, the Saturn, and discontinued advertising for Genesis hardware. The Sega CD sold 2.24 million units worldwide.[103]

Sega 32X

Main articles: 32X and List of 32X games

With the release of the Saturn scheduled for 1995, Sega began developing a stopgap to bridge the gap between the Genesis and Saturn and serve as a less expensive entry into the 32-bit era.[149] At the Winter Consumer Electronics Show in January 1994, Sega of America research and development head Joe Miller took a phone call from Nakayama, in which Nakayama stressed the importance of a quick response to the Atari Jaguar. One idea came from a concept from Sega Enterprises, "Project Jupiter," a new standalone console.[150] Project Jupiter was initially planned as a new version of the Genesis, with an upgraded color palette and a lower cost than the Saturn, and limited 3D capabilities thanks to integration of ideas from the development of the Sega Virtua Processor chip. Miller suggested an alternative strategy, citing concerns with releasing a new console with no previous design specifications within six to nine months.[151] At the suggestion from Miller and his team, Sega designed the 32X as a peripheral for the existing Genesis, expanding its power with two 32-bit SuperH-2 processors.[152] The SH-2 had been developed in 1993 as a joint venture between Sega and Japanese electronics company Hitachi.[153] At the end of the Consumer Electronics show, with the basic design of the 32X in place, Sega Enterprises invited Sega of America to assist in development of the new add-on.[151]

Although the new unit was a stronger console than originally proposed, it was not compatible with Saturn games.[152] Before the 32X could be launched, the release date of the Saturn was announced for November 1994 in Japan, coinciding with the 32X's target launch date in North America. Sega of America now was faced with trying to market the 32X with the Saturn's Japan release occurring simultaneously. Their answer was to call the 32X a "transitional device" between the Genesis and the Saturn.[150] This was justified by Sega's statement that both platforms would run at the same time and that the 32X would be aimed at players who could not afford the more expensive Saturn.[142]

The 32X was released in November 1994, in time for the holiday season. Demand among retailers was high, and Sega could not keep up orders for the system.[152] More than 1,000,000 orders had been placed for 32X units, but Sega had only managed to ship 600,000 units by January 1995.[142] Launching at about the same price as a Genesis console, the price of the 32X was less than half of what the Saturn's price would be at launch.[149] Though positioning the console as an inexpensive entry into 32-bit gaming, Sega had a difficult time convincing third-party developers to create games for the new system. After an early run on the peripheral, news soon spread to the public of the upcoming release of the Sega Saturn, which would not support the 32X's games. The Saturn was released on May 11, 1995,[154] four months earlier than its originally intended release date of September 2, 1995.[155] The Saturn, in turn, caused developers to further shy away from the console and created doubt about the library for the 32X, even with Sega's assurances that there would be a large number of games developed for the system. In early 1996, Sega conceded that it had promised too much out of the 32X and decided to stop producing the system in order to focus on the Saturn.[142] Prices for the 32X dropped to $99 and cleared out of stores at $19.95.[152]


More than a dozen licensed variations of the Genesis/Mega Drive have been released.[156] In addition to models made by Sega, alternate models were made by other companies, such as Majesco Entertainment, AtGames, JVC, Pioneer Corporation, Amstrad, and Aiwa. A number of bootleg clones were created during its lifespan.[25]

First-party models

In 1993, Sega introduced a smaller, lighter version of the console,[118] known as the Mega Drive II in Japan, Europe, and Australia[e] and sold as Genesis (without the Sega prefix) in North America. This version omits the headphone jack, replaces the A/V-Out connector with a smaller version that supports stereo sound, and provides a simpler, less expensive mainboard that requires less power.[121]

Sega released a combined, semi-portable Genesis/Sega CD unit, the Genesis CDX (marketed as the Multi-Mega in Europe). This unit retailed at $399.95 in the US;[157] this was roughly $100 more than the individual Genesis and Sega CD units put together, as the Sega CD had been reduced to $229 half a year before.[158] The CDX was bundled with Sonic CD, Sega Classics Arcade Collection, and the Sega CD version of Ecco the Dolphin.[159] The CDX features a small LCD screen that, when the unit is used to play audio CDs, displays the current track being played.[160] With this feature and the system's lightweight build (weighing two pounds), Sega marketed it in part as a portable CD player.[157]

Late in the 16-bit era, Sega released a handheld version of the Genesis, the Genesis Nomad. Its design was based on the Mega Jet, a Mega Drive portable unit featured on airplane flights in Japan. As the only successor to the Game Gear, the Nomad operates on 6 AA batteries, displaying its graphics on a 3.25-inch (8.25-mm) LCD screen. The Nomad supports the entire Genesis library, but cannot be used with the Sega 32X, the Sega CD, or the Power Base Converter.[161]

Exclusive to the Japanese market was the TeraDrive, a Mega Drive combined with an IBM PC compatible computer. Sega also produced three arcade system boards based on the Mega Drive: the System C-2, the MegaTech, and the MegaPlay, which support approximately 80 games combined.[25]

Third-party models

Working with Sega Enterprises, JVC released the Wondermega on April 1, 1992, in Japan. The system was later redesigned by JVC and released as the X'Eye in North America in September 1994. Designed by JVC to be a Genesis and Sega CD combination with high quality audio, the Wondermega's high price ($500 at launch[162]) kept it out of the hands of average consumers.[163] The same was true of the Pioneer LaserActive, which requires an add-on known as the Mega-LD pack, developed by Sega, in order to play Genesis and Sega CD games. Although the LaserActive was lined up to compete with the 3DO Interactive Multiplayer, the combined price of the system and the Mega-LD pack made it a prohibitively expensive option for Sega players.[164] Aiwa released the CSD-GM1, a combination Genesis/Sega CD unit built into a boombox. Several companies added the Mega Drive to personal computers, mimicking the design of Sega's TeraDrive; these include the MSX models AX-330 and AX-990, distributed in Kuwait and Yemen, and the Amstrad Mega PC, distributed in Europe and Australia.[25]

After the Genesis was discontinued, Majesco Entertainment released the Genesis 3 as a budget version in 1998.[165] A similar thing happened in Portugal, where Ecofilmes, Sega's distributor in the country, obtained a license to sell the Mega Game II. This version was more akin to the second first-party model, being noteworthy the inclusion of six-button controllers and a switch to alternate between different game regions, enabling this version to play all games without the need for any device or modification to bypass region locking.[166] In 2009, AtGames began producing two new variations: the Firecore, which can play original Genesis cartridges as well as preloaded games, and a handheld console preloaded with 20 Genesis games.[167] Companies such as Radica Games have released various compilations of Genesis and Mega Drive games in "plug-and-play" packages resembling the system's controller.[168]

Re-releases and emulation

A number of Genesis and Mega Drive emulators have been produced, including GenEM, KGen, Genecyst, VGen,[169] Gens,[170] and Kega Fusion. The GameTap subscription gaming service included a Genesis emulator and had several dozen licensed Genesis games in its catalog.[171] The Console Classix subscription gaming service includes an emulator and has several hundred Genesis games in its catalog.[172]

Compilations of Genesis games have been released for other consoles. These include Sonic Mega Collection and Sonic Gems Collection for PS2, Xbox, and Nintendo GameCube; Sega Genesis Collection for PS2 and PSP; and Sonic's Ultimate Genesis Collection (known as the Sega Mega Drive Ultimate Collection in PAL territories) for PlayStation 3 and Xbox 360.[173][174]

During his keynote speech at the 2006 Game Developers Conference, Nintendo president Satoru Iwata announced that Sega would make a number of Genesis/Mega Drive games available to download on the Wii's Virtual Console.[175] There are select Genesis games available on the Xbox 360 through Xbox Live Arcade, such as Sonic the Hedgehog and Sonic 2,[176] as well as games available via the PlayStation Network[177] and Steam.[178]

Later releases

On May 22, 2006, North American company Super Fighter Team released Beggar Prince, a game translated from a 1996 Chinese original.[179] It was released worldwide and was the first commercial Genesis game release in North America since 1998.[180] Super Fighter Team would later go on to release two more games for the system, Legend of Wukong and Star Odyssey.[180] In December 2010, WaterMelon, an American company, released Pier Solar and the Great Architects, the first commercial role-playing video game specifically developed for the console since 1996,[181] and was the biggest 16-bit game ever produced for the console at the time at 64 Mb (roughly 8 Megabytes).[182]Pier Solar is the only cartridge-based game which can optionally use the Sega CD to play an enhanced soundtrack and sound effects disc.[183] In 2013, independent programmer Future Driver, inspired by the Disney film Wreck-It Ralph, developed Fix-It Felix Jr. for the Genesis.[184] In 2017, American company Mega Cat Games released Coffee Crisis, a Beat 'em up, for the Sega Genesis.[185]

On December 5, 2007, Tectoy released a portable version of the Genesis/Mega Drive with twenty built-in games.[186] Another version called "Mega Drive Guitar Idol" comes with two six-button joypads and a guitar controller with five fret buttons. The Guitar Idol game contains a mix of Brazilian and international songs. The console has 87 built-in games, including some from Electronic Arts based on the mobile phone versions.[187] It was announced that Tectoy had developed a new Genesis console that not only looks almost identical to the original model of the Genesis, but also has a traditional cartridge slot and SD card reader, which was released in June 2017.[188]

In 2009, Chinese company AtGames produced a Genesis/Mega Drive-compatible console, the Firecore.[167] It features a top-loading cartridge slot and includes two controllers similar to the six-button controller for the original Genesis. The console has 15 games built-in and is region-free, allowing cartridge games to run regardless of their region.[189] AtGames produced a handheld version of the console.[190] Both machines have been released in Europe by distributing company Blaze Europe.[189]

In 2018, Sega announced a microconsole, the Genesis/Mega Drive Mini.[191] The console includes 40 games, including Gunstar Heroes and Castlevania: Bloodlines, with different games for different regions and a save-anywhere function. Streets of Rage composer Yuzo Koshiro provided the menu music. The console was released on September 19, 2019.[192]

Crowdfunded Sega Mega Drive games have been released in recent years, with Tanglewood, a puzzle platformer being released on August 14, 2018, and Xeno Crisis released on October 28th, 2019. Both games were created by indie-game developers using actual Sega development hardware to ensure compatibility with the Mega Drive.[193] On December 16, 2020, Paprium, WaterMelon's follow up game to Pier Solar, was released after nearly a decade in development. [194]


Reviewing the Genesis in 1995, Game Players noted that its rivalry with the Super NES was skewed by genre, with the Genesis having superior sports games and the Super NES superior RPGs. Commenting that the Genesis hardware was aging and the new software drying up, they recommended consumers buy a next-generation system or a Genesis Nomad instead, but also advised those who already owned a Genesis to not sell it.[195] In a 1997 year-end review, a team of five Electronic Gaming Monthly editors gave the Genesis scores of 4.5, 5.0, 4.0, 4.5, and 7.5 - for all five editors, the lowest score they gave to any of the five consoles reviewed in the issue. While their chief criticisms were the lack of upcoming game releases and dated hardware, they also concurred that the Genesis was clearly inferior to the Super NES in terms of graphics capabilities, sound chip, and games library. John Ricciardi, in particular, considered the Genesis overrated, saying he had consistently found more enjoyment in both the Super NES and TurboGrafx-16, while Dan Hsu and Crispin Boyer recommended it based on its selection of classic titles and the high value-for-money of the six pack-in games Sega was offering at the time.[196]


The Genesis has often ranked among the best video game consoles. In 2009, IGN named it the fifth best video game console, citing its edge in sports games and better home version of Mortal Kombat, and lauding "what some consider to be the greatest controller ever created: the six button".[197] In 2007, GameTrailers named the Genesis as the sixth best console of all time in their list of top ten consoles that "left their mark on the history of gaming", noting its great games and solid controller, and writing of the "glory days" of Sonic the Hedgehog.[198] In January 2008, technology columnist Don Reisinger proclaimed that the Genesis "created the industry's best console war to date", citing Sonic the Hedgehog, superior sports games, and backward compatibility with the Sega Master System.[199] In 2008, GamingExcellence ranked it sixth of the 10 best consoles, declaring, "one can truly see the Genesis for the gaming milestone it was."[200] At the same time, GameDaily rated it ninth of ten for its memorable games.[201]

In 2014, USgamer's Jeremy Parish wrote, "If the Atari generation introduced video games as a short-lived '70s fad ... and the NES generation established it into an enduring obsession for the young, Sega's Genesis began pushing the medium toward something resembling its contemporary form", expounding that the system served as "the key incubator for modern sports franchises", made "consoles truly international" by providing Western third-parties previously put at a disadvantage by Nintendo's restrictive licensing policies with a more profitable alternative, created "an online subscription service" that foreshadowed "PlayStation Plus more than 15 years early" with the Sega Channel, and "played a key role in ensuring the vitality and future of the games industry by breaking Nintendo's near-monopolistic hold on the U.S. and awakening the U.K. to the merits of television gaming".[202]

For his part, Kalinske highlighted Sega's role in developing games for an older demographic and pioneering "the concept of the 'street date'" with the simultaneous North American and European release of Sonic the Hedgehog 2.[203] John Sczepaniak of Retro Gamer noted, "It was a system where the allure was born not only of the hardware and games, but the magazines, playground arguments, climate, and politics of the time."[25] Sega of America's marketing campaign for the Genesis was widely emulated, influencing marketing in the subsequent generation of consoles.[205]

See also



  1. ^ abSonic the Hedgehog GameTap Retrospective Pt. 3/4. GameTap. February 17, 2009. Event occurs at 1:25. Archived from the original on July 21, 2016. Retrieved September 24, 2011. cf. "Review: Sonic Jam". Sega Saturn Magazine. No. 22. August 1997. p. 68.
  2. ^"Saturday Night". Saturday Night. Vol. 111 no. 1–5. Consolidated Press Limited. 1996. p. 92.
  3. ^Counsell, Gail (November 10, 1993). "Sega slashes profit forecast: Video game group says strength of yen will hit earnings". The Independent. Archived from the original on September 30, 2021. Retrieved September 15, 2021.
  4. ^"Video game sales scale greater heights". Screen Digest. Screen Digest Limited: 271. 1992.
  5. ^"Sonic CD Slips Up"(PDF). Sega Force. No. 16 (April 1993). March 4, 1993. p. 12. Archived from the original(PDF) on March 29, 2016.
  6. ^ abFahs, Travis (April 21, 2009). "IGN Presents the History of Sega (page 5)". IGN. Archived from the original on March 22, 2016. Retrieved October 5, 2013.
  7. ^ abcdefKent, Steven L. (2001). "The War". The Ultimate History of Video Games: The Story Behind the Craze that Touched our Lives and Changed the World. Roseville, California: Prima Publishing. ISBN .
  8. ^Brandt, Richard; Gross, Neil (February 21, 1994). "Sega!". Businessweek. Bloomberg L.P.Archived from the original on December 3, 2013. Retrieved October 10, 2013.
  9. ^Pollack, Andrew (October 24, 1982). "What's New in Video Games; Taking the Zing Out of the Arcade Boom". The New York Times. Archived from the original on December 19, 2013. Retrieved November 27, 2013.
  10. ^"The Bottom Line". Miami Herald. August 27, 1983. Archived from the original on November 10, 2013. Retrieved October 10, 2013 – via NewsBank.
  11. ^Battelle, John (December 1993). "The Next Level: Sega's Plans for World Domination". Wired. Condé Nast Publications. Archived from the original on May 2, 2012. Retrieved October 9, 2013.
  12. ^ abcSato (November 5, 2018). "Former Sega President Talks About Making The Mega Drive To "Beat Nintendo"". Siliconera. Archived from the original on November 6, 2018. Retrieved November 5, 2018.
  13. ^Marley, Scott (December 2016). "SG-1000". Retro Gamer. No. 163. Future Publishing. pp. 56–61.
  14. ^ abcSato, Hideki; Famitsu DC (February 15, 2002). Interview: The Witness of History. セガ・コンシューマー・ヒストリー (Sega Consumer History). Famitsu Books (in Japanese). Enterbrain. pp. 22–25. ISBN . (Translation by Shmuplations. Archived 2020-08-14 at the Wayback Machine).
  15. ^Kohler, Chris (October 2, 2009). "Playing the SG-1000, Sega's First Game Machine". Wired Magazine's online site. Archived from the original on January 1, 2014. Retrieved October 5, 2009.
  16. ^"G&W Wins Cheers $1 Billion Spinoff Set". Miami Herald. August 16, 1983. Archived from the original on November 10, 2013. Retrieved October 10, 2013 – via NewsBank.
  17. ^Kent, Steven L. (2001). "The Birth of Sega". The Ultimate History of Video Games: The Story Behind the Craze that Touched our Lives and Changed the World. Roseville, California: Prima Publishing. p. 343. ISBN .
  18. ^Kent, Steven L. (2001). The Ultimate History of Video Games: The Story Behind the Craze that Touched our Lives and Changed the World. Roseville, California: Prima Publishing. pp. 303, 360. ISBN .
  19. ^Nintendo Official Magazine Staff (2001). Nintendo's Market Share 1988. London: EMAP. p. 35.
  20. ^Businessweek staff (1999). Nintendo's Market Share 1990. New York: Bloomberg L.P. p. 60.
  21. ^"How Sega Built the Genesis". Polygon. Vox Media. February 3, 2015. Archived from the original on November 3, 2015. Retrieved November 23, 2015.
  22. ^Harris, Blake J. (2014). Console Wars: Sega, Nintendo, and the Battle That Defined a Generation. New York, New York: HarperCollins. p. 386. ISBN .
  23. ^ abcSato (September 18, 2013). "Sega's Original Hardware Developer Talks About The Company's Past Consoles". Siliconera. Curse LLC. Archived from the original on December 2, 2013. Retrieved November 23, 2013.
  24. ^ abcFahs, Travis (April 21, 2009). "IGN Presents the History of Sega (page 4)". IGN. Ziff Davis. Archived from the original on February 21, 2014. Retrieved October 5, 2013.
  25. ^ abcdefghijklmnoSczepaniak, John (August 2006). "Retroinspection: Mega Drive". Retro Gamer. No. 27. Imagine Publishing. pp. 42–47. Archived from the original on September 24, 2015 – via Sega-16.
  26. ^"Confira uma entrevista com Mitsushige Shiraiwa, designer do visual icônico do Mega Drive original!". Blog Tectoy (in Portuguese). September 28, 2017. Archived from the original on September 30, 2021. Retrieved July 21, 2019.
  27. ^Stuart, Keith (2014). Sega Mega Drive Collected Works. Read-Only Memory. ISBN .
  28. ^"Console Yourself". New Computer Express. No. 43 (2 September 1989). August 31, 1989. p. 8.
  29. ^ abMcFerran, Damien (February 22, 2012). "The Rise and Fall of Sega Enterprises". Eurogamer. Gamer Network. Archived from the original on February 16, 2014. Retrieved October 5, 2013.
  30. ^Kent, Steven L. (2001). The Ultimate History of Video Games: The Story Behind the Craze that Touched our Lives and Changed the World. Roseville, California: Prima Publishing. p. 447. ISBN .
  31. ^Sheff, David (1993). Game Over: How Nintendo Zapped an American Industry, Captured Your Dollars, and Enslaved Your Children. New York: Random House. p. 352. ISBN .
  32. ^Kent, Steven L. (2001). The Ultimate History of Video Games. Roseville, California: Prima Publishing. pp. 404–405. ISBN .

Sega Genesis, Mega Drive Specs, Info And History

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The Sega Genesis holds a special place in my heart.

Sega Genesis Console Specifications

  • CPU: Motorola 68000 running at 7.6 MHz(main processor), Zilog Z80 at 3.58 MHz(secondary, used to control sound hardware)
  • RAM: 72 kB
  • Sound: Yamaha YM2612(FM synthesizer)/Texas Instruments SN76489(Integrated with Video Display Processor)
  • Sound Channels: 6 
  • Video Memory: 64 kB with 512 color palette and capable of displaying up to 61 colors at a time
  • Max Sprites on Screen: 64
  • Media: ROM Cartridge


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Console Generation of the Sega Genesis


Sega Genesis Lifespan

  • Sega 1988-1997
  • Third-Party 1992-


Launch Price of the Sega Genesis


Launch Dates of Sega Genesis

  • Japan: October 29, 1988
  • North America: August 14, 1989
  • Europe: September 1990
  • Australia: 1990(?)
  • Brazil: September 1, 1990



  • Japan: 1998
  • North America: 1998


Sega Genesis Units Sold

  • North America: 20 million
  • Japan: 3.5 million
  • Others: 15 million

Worldwide: 40 million


Best Selling Sega Genesis Games(units sold):

(*)Bundled with console and sold separately

  1. Sonic The Hedgehog – 15 million(*)
  2. Sonic The Hedgehog 2 – 6 million(*)
  3. Disney’s Aladdin – 4 million
  4. NBA Jam – 1.93 million
  5. Mortal Kombat 2 – 1.78 million
  6. Sonic 3 + Sonic & Knuckles(set) 1.74 million
  7. Street Fighter 2: Special Champion Edition – 1.65 million
  8. Altered Beast – 1.4 million(*)
  9. Sonic & Knuckles(game only) – 1.24 million
  10. Mortal Kombat 3 – 1.02 million


Other Names, Also Known As

  • Mega Drive(other regions)


Predecessor To The Sega Genesis


Successor To The Sega Genesis


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Specs sega genesis

Sega Mega Drive/Genesis

Console Information

In 1987, 16-bit personal computers such as the Commodore Amiga and Atari ST, and 16-bit arcade machines made video game consoles look not so good. At this time, Nintendo had a 95% market share in the US and 92% in Japan. It was no use for Sega to continue battling with its Master System console. It was time to try a new way of outdoing the competition.

Sega's arcade machines using System 16 technology had become very popular. Sega CEO Hayou Nakayama decided it was time to bring this technology into home videogame consoles. Sega began developing their new 16-bit console based on System 16. Their final design worked out so well that they used the technology to make three new arcade boards (MegaTech, MegaPlay and System C). This now meant that any game made for these arcade machines could be almost perfectly ported to their new console. Sega also made their console backwards compatible with the Sega Master System with an add-on device later named the Power Base Converter.

The last issue was to give the console a name. The official name given to it in-house was MK-1601, but a more appealing name was needed when marketing to the public. "Mega Drive" was finally decided upon by Sega executives, "mega" being a word previously used by Sega when promoting games that were larger and more powerful than others, and "drive" being a word associated with speed and power. Sega of America could not use this name as it was already trademarked by another company. They went with "Genesis" instead, meaning "in the beginning", as Sega was leading the way in the beginning of the next-generation consoles.

NEC's PC Engine was also in development at the time and posed a threat to both Sega and Nintendo as they had the resources and money to make a really good console. When the PC Engine was released in Japan on 30th October 1987, it didn't make much of an impact. When the Mega Drive was released on October 29th 1988 (for 21000 Yen) in Japan, it too didn't make any large initial impact, in fact, it made a smaller impact on the video game market than the PC Engine, despite being superior to both Nintendo\'s dominant Famicom and the PC Engine.

Sega soon announced their initial US release date of 9th January 1989 and emphasised that the Genesis was the first true 16-bit system (PC Engine (or Turbo GrafX 16 as it was called in the US) wasn\'t). The announced price was US$200. When the Genesis was released in America on 14th August 1989 (in Los Angeles and New York only. The rest of the country received it on 15th September 1989. It was priced at US$190.), it was a different story to what had happened in Japan. NEC had poorly marketed the Turbo GrafX 16 (which was released about 6 months earlier) in America and the Genesis was recognised for its arcade quality graphics and superiority to the Nintendo Entertainment System and amazed gamers because of its capabilities.

The European release of the Mega Drive was November 30th 1990. It came to the UK first (at a price of £190) because the Master System had been well supported there. Australia also received the console in 1990. The Mega Drive and Genesis are both interchangeable. Most Genesis games will work on Mega Drive without the use of an adaptor and you can play Mega Drive games on Genesis with the help of an adaptor. Sometimes when a game was not re-released on a Mega Drive cartridge, the Genesis version would be imported for play on the system.

Soon, gamers began to notice that many first generation games were repetitive as there were too many arcade ports. Sega didn't have a "killer app" that could help push their system. So until they could find one, it was up to companies like Electronic Arts (with their popular sports titles) and Capcom (with their successful Strider game) to keep people interested in Genesis.

In mid-1990, the sales of Genesis consoles surpassed 1 million in North America alone. Meanwhile, Nintendo realised that Sega was taking away their customers. They got back to work on a 16-bit console (remember that the Famicom was originally going to be 16-bit but it would have cost far too much to produce back in 1983). They came up with the Super Famicom and released it on 21st November 1990 in Japan. It was then released as the Super Nintendo Entertainment System in the US on September 1st 1991. The 16-bit war had begun.

To challenge Nintendo, Sega had everything it needed except for a mascot, a marketing campaign and a killer app. These three wishes were granted for Sega when they began accepting applications for mascots. The final decision was Sonic the Hedgehog. Not only would this become the "killer app" for the system, but Sega also now had the perfect mascot that emphasised the system's speed. Speed was the one thing that the Genesis excelled in and the SNES didn't. Sega's marketing campaigns were now all based around speed and aggressive advertising. Sonic even became the pack-in game with the console in place of Altered Beast. Sales skyrocketed.

1992-93 were Sega's best days. All their efforts and advertising had paid off. Great games were still being made and more and more third party companies were producing games for the console. The Mega CD/Sega CD had been released and so Sega were once again ahead of Nintendo technology-wise. Sega also released a Mega Drive II/Genesis II console that was smaller than the original and did not include a headphones jack or volume control. The Mega CD/Sega CD was also redesigned to fit with the new Mega Drive/Genesis, however, both versions of Mega CD/Sega CD will work on either console. It was in 1993 that Sega pulled ahead of Nintendo in the North American market share. But with all of this success, they began slacking off.

Things weren't so good by the end of 1994. Sega had not been advertising as much anymore. The Mega CD/Sega CD was not selling so well and Sega was now in debt because of it. The development and cost of producing the 32X also helped contribute to this debt. 32X was not selling well either. There were also disputes between Sega of Japan and Sega of America. All of this gave Sega a bad image to gamers and programmers. Not to mention the concern over violence in video games that had began the year before after the release of Mortal Kombat in which the Sega version was true to the arcade version, leaving all of the violence in, while the Nintendo version censored the really violent parts. Although Sega's version outsold Nintendo's 4 to 1, it was not giving Sega a good image. To try and regain respect, Sega introduced the VRC (The Videogames Rating Council), which somewhat helped, but not enough. Things kept going downhill for Sega.

Sega's market share had now fallen from 65% to 35% within one year. Sony's Playstation had also been announced (as well as earlier announcements of Nintendo's planned Project Atlantis). Sega needed a new console in order to stay in the market and so they announced the Sega Saturn. But that's a different story.

In 1996, Sega announced it would drop support for the Genesis in favour of the Saturn. This was a bad move. People no longer wanted to be bothered with the Genesis anymore and supported Nintendo and Sony instead.

The Mega Drive was still supported up until 1998 in Europe where it outsold all other consoles, even the Sega Saturn. Nintendo could not seem to get as strong a hold of the European market as Sega had. In Brazil, Tec Toy (distributors/manufacturers for Sega in Brazil) had success with the Genesis up until 1998 as well, just as it had with the Sega Master System. Genesis had a 75% market share in Brazil.

In 1997, Majesco Sales wanted to produce a low-budget version of the Genesis that left out a few features and so it could be sold at the low price of US$50 as an alternative to the more expensive Sony and Nintendo consoles on the market. It was called the Genesis 3 and was released in 1998 only in North America.

There were also a number of clone Mega Drive/Genesis consoles released, some being combined with 32X, Mega CD/Sega CD or even Personal Computers.

The Mega Drive/Genesis did fairly well in most places where it was released, mostly due to its arcade ports, sports games and platforms. Although it did not win the 16-bit war, it sure did shake things up for Nintendo and made its mark in console history.

Sega Mega Drive/Genesis Technical Specifications

  • CPU: 16-bit Motorola 68000 running at 7.61 MHz
  • Co-processor: Zilog Z80 running at 4 MHz (Not Present in model MK-1631) controls PSG (Programmable Sound Generator) & FM Chips
  • RAM: 64 Kbytes
  • ROM: 1 Mbytes (8-Mbit)
  • VRAM: 64 Kbytes (Video Ram)
  • Graphics: VDP (Video Display Processor) dedicated video display processor for playfield and sprite control, 3 Planes, 2 scrolling playfields, 1 sprite plane
  • Colours Available: 512
  • Max. Colours on screen: 64
  • CRAM: 64 x 9-kbit (Colour RAM)
  • Pixel Resolution: 320 x 224, 40 x 28 text display mode
  • Sound: Texas Instruments PSG (Programmable Sound Generator) TI 76489 chip, Yamaha YM 2612 FM chip
  • Signal/Noise Ratio: 14dB
  • Sound Channels: 6 stereo sound channels
  • Sound RAM: 8 Kbytes
  • 1 sidecar expansion slot
  • 1 cartridge port
  • 2 joystick ports
  • AV port
  • Backwards compatible with all Sega Master System games using converter
  • System Development Status: Complete
  • System Release Status: Released

Platform: Sega Mega Drive/Genesis.

Sega/Mega CD - [ Sega Genesis/Megadrive | Sega 32x ]

Released in 1992, the SegaCD add on to the Genesis was to add a whole new realm of gaming to Genesis owners. The peripheral never achieved major success hoped for by Sega due to its cost, and the lack of any major incentives for purchasing the add on. The extra capacity allowed for much better audio quality and for the use of FMV, just wasn't enough to attract buyers. Sega launched the peripheral with a campaign dubbed: Welcome to the next level. aka: Welco/Metot/Henex/Tlevel.

The original Sega CD unit used a tray mechanism for the CD, and rested below the Genesis unit. With the launch of the Genesis 2, the Sega CD 2 also appeared. THe SCD2 CD mechanism used the cheaper flip lid. It connected on the side of the Genesis 2, resting next to the unit.

Source: Sega CD1 Users Manual (Part#: 672-0955), Sega Online

  • Model Number: MK-1690 (r1), MK-4102 (r2)
  • CPU: Motorola 68000 @ 12.5MHz
  • Memory:
    • 6Mbit (Program, picture data, sound data)
    • 512Kbit (PCM waveform memory)
    • 128Kbit (CD-ROM data cache memory)
    • 64Kbit (Backup memory)
    • 1Mbit (Boot ROM)
  • Sound:
    • PCM Sound Source:
      • Stereo, 8 Channels.
      • Sampliing wavelength: 32MHz max.
    • D/A Convertor:
      • 16-bit D/A convertor
      • 8x Internal over-sampling digital filter
      • PCM and CD sound mixing.
      • Mixing with mixing terminal possible
    • Audio Characteristics:
      • Wavelength characteristics: 20Hz-20kHz.
      • Signal/Noise Ratio: Over 90dB (1kHz) (Line Out).
      • Stereo channel separation: Over 90dB.
  • Misc.
    • Battery Backup Durection: Approx. 1 month
    • 1x CD-Rom Drive Speed (150kb/s)
    • Audio Out: L/W RCA pin jack.
    • Dimensions (WHD): 301mm x 212.5mm x 112.5mm (r1),

Sega 32x - [ Sega Genesis/Megadrive | Sega/Mega CD ]

Released in Fall 1994, the 32x was yet another peripheral for the Genesis. This one promised 32-bit power, and high color graphics. Marketed as a stepping stone to the 32-bit world, and a cheaper alternative to future full 32-bit ssytems, the 32x was doomed to a short life by the lack of decent launch titles, and the impending launch of the Saturn. The 32x was a very expensive failure for Sega. Only 27 32x games were released.

The addon plugged into the cartridge port of the Genesis and connected via various A/V cables. It utilized a cartidge storage system to ensure compatability with existing Genesis titles. It was originally desgined for use on the Genesis 1/2 and CDX. But due to the lack of FCC approval, the devices' use on the CDX was not marketed/recommended.

Source: Sega

  • Model Number: MK-84000 or MK-84000a.
  • CPU: Dual Hitachi SH-2 RISC Processors @ 23 MHz each, 40MIPS.
  • Co-Processors:
    • Genesis 68000, and Z80
    • Genesis 32X VDP
  • Graphics:
    • 32,768 simultaneous colours on screen
    • Genesis resolution
    • Overlaying over existing Genesis/SegaCD video
    • 50,000 texture-mapped polygons/sec
    • Texture mapping
    • Hardware scaling and rotation
  • Sound:
    • Stereo PCM chip
    • Audio mixing with Genesis sound
    • Additional 2 channels (8 Channels total, or 16 with SegaCD)

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Mega Drive Architecture

Supporting imagery

A quick introduction

Sega (and their TV ads) want you to know: It’s impossible to bring decent games without faster graphics and richer sounds.

Their new system includes lots of already familiar components ready to be programmed. This means that, in theory, developers would only need to learn about Sega’s new GPU… right?


This console has two general purpose processors.

Firstly, we’ve got a Motorola 68000 running at ~7.6MHz, a popular processor already present in many computers at that time, such as the Amiga, the (original) Macintosh, the Atari ST… Curiously enough, each one of them succeeded its ‘6502 predecessor’ and while the Master System (Mega Drive’s precursor) doesn’t use a 6502 CPU, the NES did (and in some way, Sega’s goal was to win Nintendo consumers over). All in all, you can see a bit of correlation between the evolution of computers and game console technology.

Back on topic, the 68k has the role of ‘main’ CPU and it will be used for game logic, handling I/O and graphics calculations. It has the following capabilities:

  • 68000 ISA: A new instruction set with plenty of features, including a set of multiplication and division instructions. Some instructions are 8-bit long (byte), others 16-bit long (word) and the rest are 32-bit long (long-word).
  • 32-bit registers: This is a big step, considering the 6502 and Z80 only have 8-bit registers.
  • 16-bit ALU: Meaning it needs extra cycles to compute arithmetic operation on 32-bit numbers, but it’s fine on 16-bit/8-bit ones.
  • External 16-bit data bus: As you can see, while this CPU has some ‘32-bit capabilities’, it hasn’t been designed to be a complete 32-bit machine. The width of this bus implies better performance when moving 16-bit data around.
    • Interestingly enough, Motorola debuted a complete 32-bit CPU, the 68020, four years before this console’s release. But I imagine costs would’ve skyrocketed had Sega chosen the latter chip.
  • 24‑bit address bus. This means that up to 16 MB of memory can be accessed, but addresses are still interpreted as 32-bit values inside the CPU (the upper byte is just discarded). The bus is physically connected to:
    • 64 KB of RAM.
    • Cartridge ROM (up to 4 MB).
    • Two Controllers.
    • VDP’s registers, ports and DMA.
    • Motherboard’s registers (identifies the console).
    • Expansion ports (used for ‘future’ accessories).
    • Second CPU’s RAM (Controller by a bus arbiter).

(If you wonder the reason behind using 24-bit addresses with a CPU that can handle 32-bit addresses, I doubt that in the 80s many were asking to manage 4 GB of RAM and adding unused lines is costly in terms of performance and money).

Secondly, there’s another CPU fitted in this console, a Zilog Z80 running at ~3.5 MHz. This is the same processor found on the Master System and it’s mainly used for sound control. It features:

  • Z80 ISA: An extension of the Intel 8080 ISA, it handles 8-bit words.
  • 8-bit registers and 8-bit data bus: No surprises here.
  • 4-bit ALU: This may be a bit shocking, but it managed to handle 8-bit operations without problems, it just takes two cycles per number.
    • Notice how the 6502 runs at ~2 MHz in some systems while this ones almost reaches 4 MHz: Clock speed doesn’t make the Z80 faster per se, but helps to balance the lack of transistors in some areas.
  • 16-bit address bus with the following address map:
    • 8 KB of RAM.
    • Two sound chips.
    • 68000’s RAM (again, handled by the bus arbiter).

Both CPUs run in parallel.

Memory available

The main CPU contains 64 KB of dedicated RAM to store general-purpose data and the Z80 contains 8 KB of RAM for sound-related operations.


Sega chose two independent processors that have no awareness of each other, so how can games manage both at the same time? Well, the main program is executed in the 68000, and this CPU can subsequently write on Z80’s RAM. So, it’s possible for the 68000 to send a program to the Z80’s RAM and make the Z80 load it (by sending a reset signal to that CPU). Once the Z80 is under control, it can be used to manage the sound sub-system and move memory around using the previously described method, all of this while the 68000 is running other operations.

Because one CPU will have to step in the other’s CPU bus and both can’t use it at the same time, there’s an extra component called Bus arbiter that must be activated to stall either processor, so memory can be written without hazards.

It’s important to point out that this design can underperform if not managed properly, so games will have to take special care of the bus arbiter and watch for not stalling either CPU for longer than needed.


Blast Processing!

Graphics data is processed by the 68000 and rendered on a proprietary chip called Video Display Processor (or ‘VDP’ for short) which then sends the resulting frame for display.

The VDP runs at ~13 MHz and supports multiple resolution modes depending on the region: Up to 320x224 pixels in NTSC and up to 320x240 pixels in PAL.

This chip has two modes of operations:

  • Mode IV: Legacy mode that behaves like its predecessor.
    • This doesn’t mean this console will play Master System games automatically, an additional accessory (the Power Base Converter) is required to fit previous cartridges on this console, the converter will also instruct the I/O chip to put the Z80 in control.
  • Mode V: Native mode of operation, we’ll focus on this one.

What about Mode 0 to III? Well, these belong to the even older SG-1000 and the Mega Drive doesn’t support them.

Organising the content

The graphics content is distributed across 3 regions of memory:

  • 64 KB VRAM (Video RAM): Contains most of the graphics data.
  • 80 B VSRAM (Vertical Scroll RAM): The VDP supports vertical and horizontal scrolling, V-scroll values are stored in this separate space.
  • 128 B CRAM (Colour RAM): Stores four palette entries with 16 colours each (including transparent), the system provides 512 colours to choose from. Additionally, Highlight and Shadow effects can be applied to each palette to achieve a wider range of colours per palette.

Constructing the frame

The following section explains how the VDP draws each frame, for demonstration purposes Sonic The Hedgehog is used as example. I recommend checking out the functioning of its predecessor since there will be a lot revisited in here.


Just like Nintendo’s PPU, The VDP is a tile-based engine and as such it uses tiles (basic 8x8 bitmaps) to compose graphic planes. Each tile is coded in a simple 4-byte array where each 4-bit entry corresponds to a pixel and its value corresponds to a colour entry.

Game cartridges contain tiles in their ROM but they have to be copied to VRAM so the VDP can read them. Traditionally, this was only possible during specific time frames and handled by the CPU, fortunately this console added special circuitry to offload this task to the VDP (we’ll get into details later on).

Tiles are be used to build a total of 4 planes which, merged together, form the frame seen on the screen. Planes' tiles will overlap with each other, so the VDP will decide which tile is going to be visible based on the type of plane and the tile’s priority value.

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The Background plane, also known as Plane B is a scrollable tilemap containing static tiles.

This plane can have six different dimensions: 256x256, 256x512, 256x1024, 512x256, 512x512, 1024x256. The choice can be based on the type of scrolling that will be required.

Each tile can be flipped horizontally and/or vertically and have a priority set.

On the showed example you’ll notice that the selected area for display is not a square… It doesn’t have to! The VDP allows to set up horizontal scrolling values for the whole frame, each individual scan-line or for every eight pixels. This means that developers can shape the selected area like a rhomboid and alter its angles while the player moves in order to achieve a Parallax effect. Tricks like this one don’t result in a distorted plane, the VDP fetches each (selected) horizontal line and builds a squared frame from it.

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The Foreground plane, also known as Plane A, has the same properties as the Background Plane except this plane has a higher priority, so tiles rendered here will inherently be on top of the Background Plane.

Additionally, this plane allows to divide itself to form a new sub-plane: The Window Plane. The only difference is that the latter doesn’t scroll.

Compared to previous consoles, the combination of different priorities and the Window plane allows to achieve a more convincing illusion of depth.

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In this plane, tiles are treated as sprites, they are positioned in a 512x512 px map and only a part of it (VDP’s output resolution) is selected for display. This is convenient for hiding unwanted sprites or preparing others that will be shown in the future. The VDP also provides an old collision detection function.

Sprites are formed by combining up to 4x4 tiles (32x32 map) and selecting up to 16 colours (including transparent), if a bigger sprite is needed then multiple sprites can be combined into one.

There can only be a maximum of 20 sprites per scan-line and 80 per screen (overflowing this will corrupt the whole layer).

The region in VRAM where Sprites are defined is called Sprite Attribute Table and each entry contains the tile index, layer coordinates (x and y), Link value (manages which sprites are drawn first), priority (the sprite with highest priority is the one to be displayed during overlaps), colour palette index and vertical and horizontal flip.

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While the frame is being drawn, the system will sequentially call different interrupt routines depending where the CRT’s beam is pointing to. As you probably seen before in previous consoles, this allows the CPU to work on the next frame (or alter the current one).

Conventionally, there are two types of interrupts called: H-Blank (every horizontal line) and V-Blank (every frame).

H-Blank is called numerous times but is limited to executing short routines, only CRAM and VSRAM are accessible, so games can only update their colour palettes or vertically scroll their planes.

V-Blank allows for longer routines with the drawback of being called only 50-60 times per second, it’s also able to access all memory locations.

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A dedicated transfer unit

So far we’ve discussed what the CPU can do to update frames, but what about the VDP? This chip actually features Direct Memory Access (‘DMA’ for short) that allows to move memory around at a faster rate without the intervention of the CPU.

The DMA can be activated during H-Blank, V-Blank or active state (outside any interrupt), each one will have a different bandwidth. Additionally, during any DMA transfer the CPU will be blocked, this means the timing is critical to achieve performance.

If used correctly, you’ll gain high resolution graphics, fluid parallax scrolling and high frame-rates. Moreover, your game may also be featured on TV ads with lots of Blast Processing! signs all over it.

Video Output

This console has the same video out port of the Master System.


The Mega Drive houses two sound chips: A Yamaha YM2612 and a Texas Instruments SN76489.


Each chip provides very different capabilities:

Yamaha YM2612

An FM synthesiser that runs at the 68000 speed and supports six FM channels, one can be used to play PCM samples (8-bit resolution and 32 KHz sampling rate).

Frequency modulation or ‘FM’ synthesis is one of many professional techniques used for synthesising sound, it significantly rose in popularity during the 80s and made way to completely new sounds (many of which you can found listening to the tunes from that era).

In a strict nutshell, the FM algorithm takes a single waveform (carrier) and alters its frequency using another waveform (modulator), the result is a new waveform with a different frequency (and sound). The carrier-modulator combination is called operator, multiple operators can be chained together to form the final waveform, different combinations achieve different results. This chip allows 4 operators per channel.

Compared to traditional PSG synthesisers, this was a drastic improvement: You were no longer stuck with pre-defined waveforms.

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Texas Instruments SN76489

A PSG chip that can produce three pulse waves and one noise.

This is actually the original Master System’s sound chip and it’s embedded in the VDP, it runs at the speed of the Z80.

Notice the ‘Pulse 3’ channel remains unused, this is indeed reserved to play the effects during gameplay.

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Both chips can output sound at the same time, the audio mixer will then receive both signals and merge them before sending it through the audio output.

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The conductor

The Z80 is the only CPU capable of sending commands to those two chips, which is a relief for the 68000 since the latter is already fed up with other tasks.

However, let’s not forget that the Z80 is an independent processor by itself, so it needs its own program (stored in the 8 KB of RAM available) which will enable it to interpret the music data received from the 68000 and effectively manipulate the two sound chips accordingly. This program is called sequencer or driver.

Now, some games may decide to exploit the PCM channel, and for that they also need to plan a way to continuously sequence and stream their music using the rest of RAM available. The main constraint is that in order to fill that memory, the main bus has to be blocked first (so no commands or samples can be sent to the audio chips during that timeframe). If this issue wasn’t tackled properly, different sound anomalies could appear (muting, frozen notes, low sample rates, etc).

Cracking sampling

I’ve decided to dedicated a section for those who successfully manage to overcome the aforementioned constraint. Instead of just sticking with ordinary drum kits, some games found incredible ways to stream richer samples to that single PCM channel, check out these examples:

I know, they are nowhere near CD quality, but bear in mind those sounds were once deemed impossible to reproduce in this console and I’m not even emphasising how much progress this represents compared to the previous generation, so they certainly deserve some merit at least!

Assisted FM Composition

If programming an FM synthesiser was already considered complicated using the controls of an electronic keyboard (the Yamaha DX7 is a good example of this), imagine how much it was using only pure assembly…

Luckily, Sega ended up producing a piece of software for PC called GEMS to facilitate the composition (and debugging) of music. It was a very complete tool, among lot of things it included lots of patches (already configured operators to choose from), which would also explain why some games have very similar sounds.

The audio subsystem enabled games to create more channels than allowed and assign each one a priority value, then when the console would play the music, it dynamically dispatched the music channels to the available slots based on priorities. Additionally, channels with a high priority but without music could be automatically skipped.

Channels also contained some logic by implementing conditionals inside their data, this allows music to ‘evolve’ depending of how the player moves in the game.

(Bonus) Mega CD Sound

Here’s an interesting fact: The Mega CD add-on provided 2 extra channels for CD Audio (among other things). One of its most famous games, Sonic CD, had very impressive music quality but like all games it had to loop, the problem was that looping music on a 1x CD reader had noticeable gaps, so the game included loop fillers that were executed from another PCM chip while the CD header was returning to the start.

These fillers are only found on early betas of the game and they didn’t make it for the release, the remake finally included them. This is one of the levels of the game:

Have you noticed the gap on the Mega CD’s version?


They are mainly written in 68000 assembly while the sound driver is in Z80 assembly. Both reside in the cartridge ROM and can size up to 4 MB without the need of a mapper.

In terms of expandability, this design wasn’t as modular as the NES or the SNES. Hence, some add-ons like the 32x had to bypass the VDP (hence the need for the ‘Connector Cable’).

Only one custom chip was produced for cartridges, the Sega Virtua Processor, among other things it helped to produce polygons, although only one game included it as it resulted very expensive to produce.

Anti-piracy / Region Lock

To block imported games, Sega changed the shape of the cartridge slot between regions (it kept the same pinouts, though). Games could also block their execution by checking the value of the ‘Version Register’ which outputs the region value. An easy way to bypass this was to either buy one of those shady cartridge converters or do some soldering to bridge some pins on the motherboard that alters the Version Register.

When it comes to Anti-Piracy measures, the easiest check was on the SRAM size: Bootleg cartridges had more space than needed to fit any game, so games checked for the expected size on the startup. Programmers could also implement extra checksum checks at random points of the game in case hackers were to remove the SRAM checks. The only way to defeat this was to actually find the checks and remove them one by one… Although finding them was the trickiest part!

That’s all folks


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