Sega VCO Object

Overview

Released by Sega in 1981, the Sega VCO Object (Sega Z80-3D) arcade system board was the first system specifically designed for pseudo-3D sprite-scaling graphics, using an analog scaling technique, with Voltage Controlled Oscillators (VCOs) generating clock signals controlling the data fetched from the sprite/object ROM; the slower the clock signal, the larger the sprite on screen.

In 1982, SubRoc-3D also introduced an active shutter 3D system, jointly developed by Sega with Matsushita (now Panasonic).

The Sega VCO Object system was a presursor to Sega's more famous Super Scaler series of arcade system boards and graphics engines.

Technical Specifications

• CPU:
  • Turbo & SubRoc-3D: Z80 @ 5 MHz (8-bit & 16-bit instructions @ 0.725 MIPS)
  • Buck Rogers: 2× Z80 @ 5 MHz (8-bit & 16-bit instructions @ 1.45 MIPS)
• Sound board: Sega Sound Board
  • Sound chip: Custom
  • Audio output: Stereo
• Display resolution:
  • Standard resolution: 256×224 to 320×264 (horizontal), 224×256 to 264×320 (vertical)
  • Analog scaling resolution: 512×224 to 640×264 (horizontal), 224×512 to 264×640 (vertical)
• Refresh rate: 60 Hz (V-sync)
• Frame rate: 30 frames per second (SubRoc-3D), or 60 frames per second (Turbo, Buck Rogers)
• Color palette: 832 (Turbo), or 768 (SubRoc-3D), or 1536 (Buck Rogers)
• Colors on screen: 256 (Turbo, SubRoc-3D), or 1024 (Buck Rogers)
• Background planes: 2
  • Tilemap layer: 8×8 pixel tiles, 4 colors per tile, scrolling, tile flipping
  • Bitmap layer
• Sprite capabilities: Pseudo-3D sprite-scaling (analog scaling), line buffer, 64 sprites on screen, 16 sprites per scanline, 4 to 8 colors per sprite
  • Sprite pixels/texels: 4.992 MHz (standard) to 9.984 MHz (scaling) pixel clock,^[1][2] 83,200 (standard) to 166,400 (scaling) pixels/texels per frame, 315 (standard) to 630 (scaling) sprite pixels/texels per scanline
• SubRoc-3D capabilities: Stereoscopic 3D, active shutter 3D system