Sega OutRun hardware

From Sega Retro

OutrunHardware topboard.jpg
Sega OutRun hardware
Manufacturer: Sega
Release Date RRP Code

Sega's OutRun hardware was released in 1986 with the driving game OutRun. It is a successor to their Hang-On hardware, making it the second in Sega's Super Scaler series of three-dimensional arcade hardware. It was succeeded by the Sega X Board in 1987.

The OutRun hardware, like the Hang-On hardware, has specifications similar to those of the System 16, with the addition of a second 68000 processor and a separate video board which allowed for an extra graphics layer for the road as well as sprite/texture scaling capabilities. The OutRun hardware can do everything the Hang-On hardware can do, but its processors are clocked higher (allowing for quicker calculations), it has more memory, and the video board's capabilities have been expanded, capable of drawing two roads (the Hang-On hardware can only draw one) and rendering sprites/textures using a framebuffer system with a higher fillrate (the Hang-On hardware used a line-buffer system). At the time, the OutRun hardware was a very powerful but expensive arcade board, with arcade operators advised to charge twice as many credits than for regular arcade machines.

Three games made use of the hardware, all of which are driving games. However, only OutRun and Turbo OutRun are truly for this hardware, as Super Hang-On was also released for the Hang-On hardware in a mostly identical form.

Technical Specifications

  • Board composition: CPU Board, Video Board [1]
  • Main CPU: 2× 68000 @ 12.5 MHz: 16/32‑bit instructions, 4.375 MIPS, 32‑bit (2× 16‑bit) data bus, 48‑bit (2× 24‑bit) address bus [2]
  • Memory Mapper FPGA: Sega 315‑5195 Memory Mapper @ 40 MHz: 16‑bit data bus, 24‑bit address bus [3][2]

Sound

  • Sound CPU: Zilog Z80 @ 4 MHz (8/16‑bit instructions, 0.58 MIPS)
  • Sound chips: 2 chips, 24 channels, 24‑bit bus width [4]
  • Sound DAC: Yamaha YM3012 @ 4 MHz: 16‑bit floating‑point dynamic range [7]
  • Sound FPGA: Sega 315‑5223A (Signetics CK2605) @ 16 MHz: 8‑bit bus width [8][9]

Graphics

  • Video Board GPU: Sega 171‑5377 VIDEO Board graphics chipset @ 25.1748 MHz (5 processors, 88‑bit bus width) [10][1][4]
    • 315‑5197 Sega Custom Tilemap Generator FPGA: 24‑bit (24‑bit ROM, 16‑bit RAM)
    • 315‑5211 Sega Custom Sprite Generator FPGA: 32‑bit (32‑bit ROM, 16‑bit RAM)
    • 315‑5227A Signetics CK2678 PAL: 8‑bit
    • 315‑5228 Signetics CK2605 FPGA: 8‑bit [8][9]
    • 315‑5242 Sega Custom Color Encoder: 16‑bit
  • Main Board GPU: Sega 171‑5376 CPU Board graphics chipset @ 39.99967 MHz (6 processors, 21‑bit bus width) [10][1][11]
    • 2× 315‑5155 Sega Road Bit Extraction PAL: 16‑bit (2× 8‑bit), 2× 5.882353 MHz ROM (170 ns), 11.764706 MB/s ROM [12]
    • 315‑5222 Signetics PLS153N Road Mixing FPGA: 8‑bit (33.333333 MHz) internal,[13] 5‑bit (10 MHz) RAM (100 ns), 6.25 MB/s RAM
    • 315‑5223A Signetics CK2605 FPGA: 8‑bit [8][9]
    • 2× MMI PAL16R4 (315‑5225, 315‑5226) PAL: 16‑bit (2× 8‑bit) [14]
  • Video resolution: 320×224 (display), 400×262 (overscan),[1] progressive scan
    • Scanlines: 224 (display), 262 (overscan)
    • Framebuffer resolution: 512×256 pixels
  • Refresh rate: 60.0543 Hz (V‑sync) [1]
  • Color palette: 98,304
    • 16-bit color palette: 15‑bit RGB color depth (32,768 colors), 1‑bit shadow & highlight triples up to 98,304 colors
  • Colors on screen: 12,288 [1]
  • Graphical planes:
    • 2 tilemap layers: System 16B tilemap system, row & column scrolling, parallax scrolling
    • 1 text layer
    • 1 sprite layer: Hardware sprite-scaling/zooming
    • 1 road layer: Can draw 2 roads at once, 512×256 pixels each, tiled bitmaps
    • Translucent shadows
  • Sprite/texture capabilities: Frame-buffered sprites/textures with zooming capabilities, 128 on‑screen sprites per frame, 7680 sprites/textures scaled per second, 16 colors per sprite/texture
    • Video clock cycles: 25.1748 MHz (60.0543 Hz refresh rate)
    • Sprite pixel/texel fillrate: 25.1748 million pixels/texels per second,[1] 419,199 pixels/texels per frame/refresh, 1600 sprite pixels/texels per scanline, 128 sprites/textures per scanline

Memory

  • Memory: Up to 3.7 MB (736 KB main, 2572 KB video, 454 KB sound)
  • RAM: 754 KB, including 670 KB high-speed SRAM (Static RAM) [1]
    • Main RAM: 64 KB SRAM (32 KB per 68000) [2][15]
    • VRAM: 684 KB
      • CPU Board: 84 KB (4 KB sprites, 8 KB colors, 64 KB tiles, 4 KB text, 4 KB roads)
      • Video Board: 600 KB SRAM (512 KB dual sprite framebuffers)
    • Sound RAM: 6 KB SRAM (3× 2 KB) [16][17]
    • SRAM performance: 22.222222 MHz (45 ns) [17]
  • ROM: Up to 3008 KB EPROM/MROM (672 KB main ROM, 1888 KB video ROM, 448 KB sound ROM) [18][19]

Bandwidth

  • RAM bandwidth: [16]
    • Main RAM: 40 MB/s (32‑bit, 10 MHz, 100 ns)
    • Sound RAM: 25 MB/s (24‑bit, 8.333333 MHz, 120 ns) [17]
  • ROM bandwidth: [16]
    • Main ROM: 20 MB/s (32‑bit, 5 MHz, 200 ns)
    • Sound ROM: 11.764706 MB/s (16‑bit, 5.882353 MHz, 170 ns) [12]

Gallery

List of Games

References


Sega arcade boards
Originating in arcades









Console-based hardware








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