Sega X Board

Sega X Board
Manufacturer: Sega
Release Date RRP Code

The Sega X Board is an arcade system board released by Sega in 1987 as a successor to Sega OutRun hardware. It debuted with After Burner and Thunder Blade.

The X Board specification is largely similar to that of the OutRun Hardware board, but allows for twice as many sprites/textures on screen at once, twice as many tile layers, and sprite rotation effects. The contents have also been condensed onto a single board, making it slightly easier to manufacture.

The X Board would be succeeded by the Y Board and System 32, before the Model 1 made true 3D arcade games more financially affordable.

Hardware

As the third in Sega's Super Scaler series of arcade hardware (after the Sega Hang-On hardware and Sega OutRun hardware), it was noteworthy for its sprite/texture manipulation capabilities, which allowed it to create high quality three-dimensional visuals, such as the scaling and rotating environments in 1987's After Burner, and the ray casting like environments in 1988's Last Survivor. This trend would continue with the Y Board and the System 32, before the Model 1 made true polygonal 3D arcade games more financially affordable.

Technical Specifications

X Board Specifications

• Board composition: Single board
• CPU:
  • Main CPU: Hitachi FD1094 @ 12.5 MHz, Motorola MC68000 @ 12.5 MHz (16-bit & 32-bit instructions @ 4.375 MIPS)
  • Sound CPU: Zilog Z80 @ 4 MHz (8-bit & 16-bit instructions @ 0.58 MIPS)
• Sound chips:
  • FM synthesis chip: Yamaha YM2151 @ 4 MHz (8 FM channels)
  • PCM sampling chip: SegaPCM (315-5218) @ 4 MHz (stereo output, 16 PCM channels, 12-bit audio, 31.25 kHz sampling rate)
• Graphics processing unit: Sega Super Scaler chipset @ 50 MHz
  • Main graphics chips: 315-5197 tilemap generator, 315-5211A sprite generator, 315-5242 color encoder, 315-5275 road generator, 315-5278 sprite ROM bank control
  • Math chips: 315-5248 hardware multiplier, 315-5249 hardware divider
• RAM: 802 KB, including 710 KB high-speed SRAM (Static RAM)
  • Main RAM: 148 KB (including 56 KB SRAM)
    • Main CPU: 96 KB (32 KB work/program SRAM, 32 KB work/mirror RAM, 16 KB IC31, 16 KB IC32)
    • Sub-CPU: 52 KB (20 KB program SRAM, 16 KB IC31, 16 KB IC32)
  • Video RAM: 636 KB SRAM
    • Main CPU: 92 KB (64 KB background tiles, 4 KB roads, 4 KB sprites, 4 KB text, 16 KB colors)
    • Sub-CPU: 8 KB roads
    • 315-5211A: 520 KB (8 KB dual sprite banks, 512 KB dual sprite framebuffers)
    • Other VRAM: 16 KB (4 KB roads, 12 KB text)
  • Sound RAM: 18 KB SRAM (2 KB Z80 program, 16 KB SegaPCM chip)
• Video resolution: 320×224 (display), 400×262 (overscan), progressive scan
  • Scanlines: 224 (display), 262 (overscan)
• Refresh rate: 59.6368 to 60 Hz (V-sync)
  • Frame rate: 59.6368 to 60 frames per second
• Color palette: 98,304
  • 16-bit color palette: 15-bit RGB high color depth (32,768 colors) and 1-bit shadow & highlight that triples up to 98,304 colors.
• Colors on screen: 24,576
• Graphical planes:
  • 4 tile layers
  • 1 text layer
  • 1 sprite layer with hardware sprite zooming
  • 1 road layer, can draw 2 roads at once
  • Translucent shadows
• Sprite/texture capabilities: Dual sprite framebuffers, 512×256 framebuffer resolution, hardware sprite zooming, sprite rotation, ray casting
  • Sprite/texture sizes: 8×8 to 512×256 pixels
  • Colors per sprite/texture: 16
  • Sprites/textures on screen: 256 on screen at one time per frame, 15,267 to 15,360 scaled per second
  • Video clock cycles: 50 MHz
  • Fillrate: 50 million pixels/texels per second
  • Sprite pixels/texels per frame: 833,333 (at 60 Hz) to 838,408 (at 59.6368 Hz)
  • Sprite pixels/texels per scanline: 3180 to 3200 sprite pixels/texels per scanline
  • Sprites/textures per scanline: 256

Super Monaco GP Specifications

Super Monaco GP (1989) added the following upgrades:

• Additional boards: Link board, network board, sound board, motor board
• Additional CPU: 2× Zilog Z80 @ 8 MHz (2.32 MIPS)
• Additional sound CPU: Zilog Z80 @ 4 MHz (0.58 MIPS)
• Additional sound chip: SegaPCM @ 4 MHz (additional 16 PCM channels, totalling 32 PCM channels)
• Additional RAM: 40 KB, including 10 KB high-speed SRAM (Static RAM)
  • Link board: 10 KB
  • Network board: 10 KB SRAM (8 KB SRAM, 2 KB dual-port SRAM)
  • Sound board: 8 KB
  • Motor board: 12 KB
• Sound output: 4-channel surround sound

List of Games

• After Burner (1987)
• After Burner II (1987)
• Thunder Blade (1987)
• Last Survivor (1989)
• Line of Fire (1989)
• Super Monaco GP (1989)
• GP Rider (1990)
• AB Cop (1990)
• Racing Hero (1990)
• Caribbean Boule (1992)

Sega arcade boards
Originating in arcades
77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 VIC Dual G80 Zaxxon VCO Object System 1 LaserDisc Appoooh Hang-On System 2 System 16 OutRun Gigas X Board Y Board System 24 System 18 System 32 Model 1 Model 2 H1 Board Model 3
Console-based hardware
84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 SG-1000 System E System C Mega-Tech System Mega Play Sega Titan Video NAOMI Hikaru NAOMI 2 Atomiswave System SP Chihiro Triforce
PC-based hardware
05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Lindbergh Europa-R RingEdge RingWide RingEdge 2 Nu Nu 1.1 Nu 2 ALLS