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 faster bandwidth, 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

Sega OutRun Specifications

  • Board composition: CPU Board (Main 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, 44‑bit (24‑bit, 20‑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: 6 processors, 80‑bit RAM (167.521366 MB/s), 64‑bit ROM (37 MB/s)[1][3][4]
    • 315‑5197 Sega Custom Tilemap Generator FPGA: 16‑bit RAM (15.384615 MHz, 65 ns, 30.76923 MB/s), 24‑bit ROM (4 MHz, 250 ns, 12 MB/s)
    • 315‑5211 Sega Custom Sprite Generator FPGA: 16‑bit sprite attribute RAM (22.222222 MHz, 45 ns, 44.444444 MB/s),[10] 48‑bit sprite framebuffer RAM (15.384615 MHz, 65 ns, 92.307692 MB/s),[11] 32‑bit ROM (5 MHz, 200 ns, 20 MB/s)[12]
    • 315‑5227A Signetics CK2678 PAL: 8‑bit ROM (5 MHz, 200 ns, 5 MB/s)[12]
    • 315‑5228 Signetics CK2605 FPGA: 8‑bit[8][9]
    • 315‑5242 Sega Custom Color Encoder: 16‑bit
    • 8255‑2 NEC µPD8255AC‑2: 24‑bit (3× 8‑bit) PPI (Programmable Peripheral Interface)[13]
  • Main Board GPU: Sega 171‑5376 CPU Board graphics chipset @ 39.99967 MHz: 6 processors, 5‑bit RAM (6.25 MB/s), 16‑bit ROM (10 MB/s)[3][1][14]
    • 2× 315‑5155 Sega Road Bit Extraction PAL: 16‑bit (2× 8‑bit), 2× 5 MHz ROM (200 ns, 10 MB/s)[12]
    • 315‑5222 Signetics PLS153N Road Mixing FPGA: 8‑bit internal (33.333333 MHz),[15] 5‑bit RAM (10 MHz, 100 ns, 6.25 MB/s)
    • 315‑5223A Signetics CK2605 FPGA: 8‑bit internal,[8][9] 4‑bit external
    • 2× MMI PAL16R4 (315‑5225, 315‑5226) PAL: 16‑bit (2× 8‑bit)[16]
  • Fixed-point arithmetic capabilities: Z-buffering, depth map[17]
  • Video resolution: 320×224 (display), 400×262 (overscan),[1] progressive scan
  • 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
    • 1 text layer
    • 1 sprite layer
    • 1 road layer
    • Translucent shadows
  • Video clock rate: 25.1748 MHz (60.0543 Hz refresh rate)
  • Sprite plane: Sprite/Texture framebuffer, hardware sprite-scaling/zooming, 128 on‑screen sprites per frame, 7680 sprites/textures scaled per second, 16 colors (4‑bit) per sprite/texture
    • Framebuffer: 512×256 resolution, double buffering,[6] 16-bit color depth
    • Sprite/Texture sizes: 8×8 to 512×256 texels
    • Framebuffer fillrate: 46.153846 MPixels/s (92.307692 MB/s), 23.076923 MPixels/s (double buffering)
    • Sprite/Texture read fillrate: 25.1748 MTexels/s,[1] 419,200 texels per frame, 1600 texels per scanline, 128 sprites/textures per scanline
    • Sprite/Texture write fillrate: 23.076923 MTexels/s, 384,267 texels per frame (60 FPS), 419,200 texels per frame (55 FPS)
  • Tilemap planes: 2 tilemap layers, System 16B tilemap system, row/column scrolling, parallax scrolling[1][18]
    • Tilemap resolution: 512×256 (1024×512 virtual resolution)
    • Colors per tile: 8 colors (3‑bit)
    • Tile size: 8×8 pixels (24 bytes)
    • Tilemap fillrate: 25.1748 MPixels/s (393,356 tiles/sec), 419,200 pixels per frame (6550 tiles per frame)
    • Fillrate per line: 1600 pixels per line, 200 tiles per line
  • Road plane: Can draw 2 roads at once, bitmap/texture, 512×256 resolution per road[17]
    • Road fillrate: 15.742874 MPixels/s, 262,144 texels per frame, 1024 texels per line

Memory

  • Memory: Up to 3.6 MB (736 KB main, 2496 KB video, 454 KB sound)
  • RAM: 670 KB SRAM (Static RAM)[1][19]
    • Main RAM: 64 KB (32 KB per 68000)[20]
    • VRAM: 608 KB[1][4]
      • CPU Board: 8 KB (4 KB roads, 4 KB other)[10]
      • Video Board: 600 KB (512 KB dual sprite framebuffers,[6][11] 4 KB sprite attributes,[10] 64 KB tilemaps,[11] 4 KB text, 8 KB colors, 4 KB other)
    • Sound RAM: 6 KB (3× 2 KB)[10]
  • ROM: Up to 3008 KB EPROM/MROM (672 KB main ROM, 1888 KB video ROM, 448 KB sound ROM)[21][22]

Bandwidth

  • RAM bandwidth:[19]
    • Main RAM: 40 MB/s (32‑bit, 10 MHz, 100 ns)
    • VRAM: 173.771366 MB/s (85‑bit)
    • Sound RAM: 25 MB/s (24‑bit, 8.333333 MHz, 120 ns)[10]
  • ROM bandwidth:[19]
    • Main ROM: 20 MB/s (32‑bit, 5 MHz, 200 ns)
    • Video ROM: 47 MB/s (80‑bit)
    • Sound ROM: 11.764706 MB/s (16‑bit, 5.882353 MHz, 170 ns)[12]

Turbo OutRun Specifications

The Turbo OutRun hardware is largely identical, but with the following changes:[23]

Graphics

  • Video Board GPU: Sega 171‑5377 VIDEO Board graphics chipset @ 25.1748 MHz: 6 processors, 80‑bit RAM (189.898989 MB/s)
    • 315‑5197 Sega Custom Tilemap Generator FPGA: 16‑bit RAM (18.181818 MHz, 55 ns, 36.363636 MB/s)[11]
    • 315‑5211 Sega Custom Sprite Generator FPGA: 48‑bit sprite framebuffer RAM (18.181818 MHz, 55 ns, 109.090909 MB/s)[11]
  • Main Board GPU: Sega 171‑5376 CPU Board graphics chipset @ 39.99967 MHz: 6 processors, 5‑bit RAM (6.25 MB/s)
  • Sprite plane:
    • Framebuffer fillrate: 50.3496 MPixels/sec (100.6992 MB/s), 25.1748 MPixels/sec (double buffering)
    • Sprite/Texture write fillrate: 25.1748 MTexels/sec, 419,200 texels per frame (60 frames/sec)

Bandwidth

  • RAM bandwidth:
    • VRAM: 196.148989 MB/s (85‑bit)

Gallery

List of Games

References


Sega arcade boards
Originating in arcades









Console-based hardware








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