Sega Model 2
From Sega Retro
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| Sega Model 2 | |||||
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The Sega Model 2 is an arcade system board originally debuted by Sega in 1993 as a successor to the Sega Model 1 board. It is an extension of the Model 1 hardware, most notably introducing the concept of texture-mapped polygons, allowing for more realistic 3D graphics (for its time). The Model 2 board was an important milestone for the arcade industry, and helped launch several key arcade franchises of the 90s, including Daytona USA, Virtua Cop, Sega Rally Championship, Dead or Alive, Virtua Striker, Cyber Troopers Virtual-On and The House of the Dead.
The Model 2 was engineered with help from GE Aerospace (acquired by Martin Marietta in 1993, now part of Lockheed Martin), who designed the texture-mapping technology incorporated by the Model 2. The Model 2's development was led by famed game designer Yu Suzuki. The Model 2 arcade board debuted along with Daytona USA, a game which was finished, copyrighted and debuted at the JAMMA arcade show in 1993.[1]
There four versions of the system: the original Model 2 and the Model 2A-CRX, Model 2B-CRX and Model 2C-CRX variants. Model 2 and 2A-CRX used a custom DSP with internal code for the geometrizer while 2B-CRX and 2C-CRX used well documented DSPs and uploaded the geometrizer code at startup to the DSP.
Contents
Hardware
It was a further advancement of the earlier Model 1 system. The most noticeable improvement was texture mapping, which enabled polygons to be painted with bitmap images, as opposed to the limited monotone flat shading that Model 1 supported. The Model 2 also introduced the use of texture filtering and texture anti-aliasing,[2] as well as trilinear filtering.[3] It was the most powerful game system in its time, equivalent to the power of a PC graphics card in 1998, five years after the Model 2's release.[3]
Designed by Sega AM2's Yu Suzuki, he stated that the Model 2's texture mapping chip originated "from military equipment from Lockheed Martin, which was formerly General Electric Aerial & Space's textural mapping technology. It cost $2 million dollars to use the chip. It was part of flight-simulation equipment that cost $32 million. I asked how much it would cost to buy just the chip and they came back with $2 million. And I had to take that chip and convert it for video game use, and make the technology available for the consumer at 5,000 yen ($50)" ($84 in 2014) per machine. He said "it was tough but we were able to make it for 5,000 yen. Nobody at Sega believed me when I said I wanted to purchase this technology for our games."[4] Suzuki stated that, in "the end," it "was a hit and the industry gained mass-produced texture-mapping as a result." For Virtua Fighter 2, he also utilized motion capture technology, introducing it to the game industry.[5]
There were also issues working on the new CPU,[4] the Intel i960-KB, which had just released in 1993.[6] Suzuki stated that when working "on a brand new CPU, the debugger doesn't exist yet. The latest hardware doesn't work because it's full of bugs. And even if a debugger exists, the debugger itself is full of bugs. So, I had to debug the debugger. And of course with new hardware there's no library or system, so I had to create all of that, as well. It was a brutal cycle."[4]
Despite its high price tag of around $15,000[3] (equivalent to $24489 in 2014), the Model 2 platform was very successful. It featured some of the highest grossing arcade games of all time: Daytona USA,[7] Virtua Fighter 2, Cyber Troopers Virtual-On, The House of the Dead, and Dead or Alive, to name a few. Sega sold 65,000 units of the Model 2 annually,[3] and eventually sold over 130,000 units by 1996, amounting to over $1.95 billion revenue from hardware cabinet sales (130,000 units[8][9] at $15,000 each[3][10]), equivalent to over $3.18 billion in 2014, making it one of the best-selling arcade systems of all time.
Model 2 has four different varieties: Model 2 (1993),[7] Model 2A-CRX[7] (1994),[11] Model 2B-CRX[7] (1994)[12] and Model 2C-CRX (1996).[7] While Model 2 and 2A-CRX use a custom DSP with internal code for the geometrizer, 2B-CRX and 2C-CRX use well documented DSPs and upload the geometrizer code at startup to the DSP. This, combined with the fact that some games were available for both 2A-CRX and 2B-CRX, led to the reverse engineering of the Model 2 and Model 2A-CRX DSPs.
Technical Specifications
- Main CPU (central processing unit)
- Main CPU: Intel i960-KB @ 25 MHz
- Fixed-point arithmetic: 32-bit RISC instructions @ 25 MIPS (million instructions per second)[13]
- Floating-point unit: 32-bit, 64-bit and 80-bit operations @ 13.6 MFLOPS (Mega-FLOPS, or million floating-point operations per second) (Whetstone)[6]
- Geometry Engine[14] DSP coprocessors: 6× Fujitsu TGP MB86234 (Model 2/2A-CRX),[15] or 2× Analog Devices ADSP-21062 SHARC (Model 2B-CRX), or 2× Fujitsu TGPx4 MB86235 (Model 2C-CRX)[15]
- Coprocessor abilities: Floating decimal point operation function, axis rotation operation function, 3D matrix operation function
- Floating-point unit:
- Model 2/2A-CRX: 32-bit operations @ 16 MFLOPS[7] ×6 (96 MFLOPS)
- Model 2B/2C-CRX: 32-bit & 40-bit operations @ 120 MFLOPS[16] ×2 (240 MFLOPS)
- Fixed-point arithmetic: 32-bit & 48-bit instructions @ 80 MIPS (Model 2B-CRX)[16]
- Hardware Renderer:[14] Sega-Lockheed-Martin Custom rasterization[17] & texture mapping hardware (Model 2),[4] or 2× Fujitsu MB86271 AGP (Model 2C-CRX)[18]
- Z-Sort & Clip Hardware[14] (2× Fujitsu MB86272 Z-sorter in Model 2C-CRX)[18]
- Sega System 24 tilemap engine[17]
- Sound CPU: Motorola 68000 @ 10 MHz (Model 2), or Motorola 68000 @ 12 MHz (Model 2A/2B/2C-CRX)
- Sound chip: 2× Sega 315-5560 Custom MultiPCM (Model 2), or Yamaha SCSP (Model 2A/2B/2C-CRX)
- Sound timer: Yamaha YM3834 @ 8 MHz (Model 2 only)
- PCM channels: 56[7]
- PCM sample ROM: 16 Mbits (Model 2),[7] or 68 Mbits (Model 2A/2B/2C-CRX)[7]
- PCM quality: 16-bit depth,[19] 44.1 kHz sampling rate (CD quality)[7]
- SCSP features: 128-step DSP, 32 FM synthesis channels, 32 MIDI channels, 32 LFO channels[19]
- RAM (random access memory)
Total RAM: 9776 KB (Model 2/2A-CRX), or 18,388 KB (Model 2B/2C-CRX)
- Main RAM: 1152 KB (9 Mbits)[7] (1024 KB work, 64 KB network, 64 KB serial)[17]
- Video memory: 5984 KB (Model 2/2A-CRX), or 14,596 KB (Model 2B/2C-CRX)
- Framebuffer VRAM:[18] 1024 KB (Model 2/2A-CRX), or 1536 KB (Model 2B/2C-CRX)[17]
- Coprocessor buffer[17] SRAM/SDRAM:[18] 64 KB (Model 2/2A-CRX), or 8228 KB (Model 2B/2C-CRX)[17]
- Texture memory: 4096 KB[17] SRAM/SDRAM[18]
- Luma: 128 KB (Model 2/2A-CRX), or 64 KB (Model 2B/2C-CRX)[17]
- Other: 672 KB (32 KB geometry, 576 KB tiles, 64 KB colors)[17]
- Audio memory: 576 KB[17]
- Backup SRAM/NVRAM: 16 KB[17]
- Extra RAM: 2048 KB[17]
- Graphical capabilities
- Monitor display resolution: 496×384 pixels, 24 Hz horizontal sync, 60 Hz refresh rate, progressive scan (non-interlaced)[7]
- Color depth: 16,777,216 (24-bit true color)[7][20][21]
- Graphical features: Flat shading, texture mapping, perspective correction, texture filtering, texture anti-aliasing, microtexture, diffuse reflection, specular reflection, alpha blending, transparency,[7] rasterization, mipmapping, level of detail,[14] z-sorting, T&L (transform, clipping, and lighting),[14][18] trilinear filtering[3]
- Texture map resolution: Up to 1024×2048 pixels[7]
- Microtexture size: Up to 128×128 pixels
- Model 2C-CRX: Gouraud shading, hidden surface, z-buffering,[18] point sampling, bilinear filtering[21]
- Frame rate: 60 frames/sec[7]
- Geometric performance:
- Model 2: 300,000 textured quad polygons/sec[7] to over 500,000 textured triangle polygons/sec,[20] 900,000 vectors/sec[7]
- Model 2C-CRX: 490,000 textured polygons/sec (with clipping, lighting and Gouraud shading)[18] to 900,000 textured triangle polygons/sec (with Gouraud shading)[18]
- Rendering fillrate:
List of Games
- Daytona USA (1993)
- Daytona USA Deluxe '93 (1993)
- Desert Tank (1994)
- Virtua Cop (1994)
2A-CRX
- Dead or Alive (1996)
- Dynamite Baseball (1996)
- Dynamite Cop (1996)
- Manx TT Superbike (1995)
- Motor Raid (1997)
- Pilot Kids (1999)
- Sega Rally Championship (1995)
- Sega Rally Pro Drivin' (1992?)
- Sky Target (1995)
- Virtua Cop 2 (1995)
- Virtua Fighter 2 (1994)
- Virtua Fighter 2.1 (1996)
- Zero Gunner (1997)
2B-CRX games
- Dead or Alive (1996)
- Dynamite Baseball (1996)
- Dynamite Baseball 97 (1997)
- Dynamite Cop (1996)
- Fighting Vipers (1995)
- Gunblade NY (1995)
- Indy 500 (1995)
- Last Bronx (1996)
- Pilot Kids (1999)
- Rail Chase 2 (1995)
- Sonic the Fighters (1996)
- Super GT 24H (1996)
- Virtua Striker (1995)
- Cyber Troopers Virtual-On (1996)
- Zero Gunner (1997)
2C-CRX
- Behind Enemy Lines (1998)
- Dynamite Cop (1996)
- Over Rev (1997)
- Power Sled (1996)
- Sega Ski Super G (1996)
- Sega Touring Car Championship (1996)
- Sega Water Ski (1996)
- The House of the Dead (1997)
- Top Skater (1997)
- Wave Runner (1996)
Other
- Ultimate Domain (unreleased) - Developed by Atlus. Previewed in Mean Machines Sega #51.
Gallery
CPU
Video PCB
A typical ROM (Virtua Cop)
Model 2A CPU
Model 2A video PCB
Model 2A ROM (Dead or Alive)
Model 2B CPU/Video PCB
Model 2B filter PCB
Model 2B communications PCB
A Model 2B ROM
Model 2C PCB
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