Sega System C

From Sega Retro

SystemC2 Arcade PCB.jpg
Sega System C
Manufacturer: Sega
Variants: Mega-Tech System, Mega Play, System 18, System 16, Mega Drive
Release Date RRP Code
Arcade
World
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The Sega System C (セガ システム C) is an arcade board used by Sega between 1989 and 1994, and later used by Atlus for their Print Club series. A slight update called the Sega System C2 was introduced in 1990. The Columns manual refers to the hardware as Sega System 14.

Hardware

The System C hardware is built on top of the Sega Mega Drive with a few differences that make them incompatible:

  • The 68000 is clocked at ~9Mhz. The Z80 was removed; the faster 68000 allows it to handle sound without slowdown in games.
  • The VDP no longer uses its internal CRAM for palettes. Instead, it relies on external hardware to provide color information. The hardware is capable of producing 4096 possible colors which can be fed to the VDP in a variety of ways.

The System C2 adds a NEC µPD7759 ADPCM sample playback chip and a sample ROM which can be banked (as the chip can only access 128kB of samples at a time). This serves as a replacement for using the YM2612's DAC for samples, and has the extra advantage of not needing to constantly provide sample data to the µPD7759 — the 68000 merely sets the sample ROM bank and writes a sample number to play. However, the µPD7759 can only play one sample at a time.

Technical specifications

See Sega Mega Drive technical specifications for more details on base Mega Drive hardware

This hardware is based closely on the Sega Mega Drive/Genesis hardware, with the main CPU, sound processor and graphics processor being the same, but with the addition of the Altera EPM5032 and Sega 315-5242 color encoder increasing the color palette. The CPU clock speed is slightly faster (8.94 MHz instead of 7.67 MHz), there is no Z80, and the sound chip is driven by the CPU. The DAC is also replaced by the NEC µPD7759, the same as the System 16 hardware.

  • Board composition: Single JAMMA board
  • Main CPU: MC68000 @ 8.948862 MHz (16-bit & 32-bit instructions @ 1.566 MIPS)
  • Sound chips: Yamaha YM3438 @ 7.670453, SN76496 @ 3.579545
  • Optional sound chip: NEC µPD7759 @ 640 kHz (9-bit ADPCM @ 8 kHz sampling rate)
  • Graphics chips: Yamaha YM7101 VDP, Altera EPM5032, Sega 315-5242 color encoder[1][2]
  • Video resolution: 320×224 pixels
  • Color palette: 98,304[3]
  • Sega's 16-bit arcade color palette: 15-bit RGB high color depth (32,768 colors) and 1-bit shadow & highlight that triples up to 98,304 colors.

List of games

System C games

System C2 games

Note: there are a number of other Print Club games omitted from this list because they are undiscovered/undumped/etc.

References


Sega arcade boards
Originating in arcades









Console-based hardware








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PC-based hardware








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