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Sega System C / C-2 converts

The System C (1989, also called "System 14") and the System C-2 (1992) are, essentially, Mega Drive hardware in a cabinet: 68000 + 315-5313 VDP + YM3438, the C-2 adding a µPD7759 (samples). Hence a cheap, well-understood conversion — the only real lock being the 317-0xxx protection chip on the C-2 games.

Field Value
Platforms Sega System C (1989) · System C-2 (1992)
Type ROM reprog + 317-0xxx protection handling (C-2) + EEPROM/battery
Difficulty 🟡 (unprotected C game) → 🟠 (protected C-2 game)
Suicide? no program "battery key"; lock = the 317-0xxx chip

Architecture (≈ Mega Drive)

Block Chip Clock Role
CPU Motorola 68000 ~7.67 MHz (XL2 = 53.693 MHz / 7) game logic
Video 315-5313 (Mega Drive VDP) 320×224; extended palette vs Mega Drive (more on-screen colours on C-2)
Sound (FM) Yamaha YM3438 (OPN2C, YM2612-compatible) 6 FM voices
Sound (samples) µPD7759 (System C-2 only) ADPCM sample playback
Settings/save EEPROM + battery-backed RAM (per game)

It's almost a Mega Drive: same VDP, same FM family. Hence simple conversion and preservation on the video/sound side. JAMMA cabinets, 15 kHz output.

System C games (no µPD7759): Bloxeed, Columns, Columns II. System C-2 games: Puyo Puyo, Puyo Puyo 2, Puzzle & Action: Tant-R / Ichidant-R, Stack Columns, Poto Poto, Thunder Force AC, Borench, Ribbit!, Twin Squash, OOPArts…

The lock: the 317-0xxx protection chip (C-2)

Almost all C-2 games (and Bloxeed USA on the C side) carry a Sega protection chip marked 317-0xxx (a per-game number). The 68000 reads this chip and the game crashes / won't boot without the right response.

Game (examples) Chip
Bloxeed (USA) 317-0140
Columns 317-0149
Columns II 317-0160
Puyo Puyo 317-0203
Tant-R (JP) 317-0211
Ichidant-R (JP) 317-0224
Puyo Puyo 2 317-0228
  • Bloxeed (the very first, board C) does NOT read the protection → it's the easiest game to reproduce/convert.
  • The protection works as a per-game table of 256 4-bit values; it was reverse-engineered by the MAME community (the tables live in the sega/segac2.cpp driver). → a base for a conversion (supply the right protection logic) or a faithful emulation.

No classic 'de-suicide', but…

There is no battery-backed program decryption key (like CPS-2/System 16 FD1094). The lock is hardware: the game's 317-0xxx chip. To convert to a protected game you need the target game's chip (or a substitute reproducing its table). Some games also have a battery-backed RAM (scores/settings) — watch it for preservation.

Converting (summary)

  1. Gather the target game's ROMs (68000 program, graphics, sound; + µPD7759 samples if C-2).
  2. Burn the EPROMs at the right sizes/positions on a compatible donor board (C vs C-2 depending on the µPD7759).
  3. Handle the protection:
  4. unprotected game (Bloxeed, bare C board) → nothing special;
  5. 317-0xxx game → supply the game's chip (or a substitute reproducing its 256×4-bit table, derived from MAME).
  6. Handle the EEPROM / battery (settings, possible backup) — reset as needed.
  7. Test: video (VDP), FM (YM3438), samples (µPD7759 on C-2), save.

Settings (DIP)

System C/C-2 are configured with DIP switches (coinage, difficulty, options) and/or EEPROM soft-dips depending on the game. After a conversion, apply the target game's table — see the general DIP convention.

Before / after

  • Unprotected System C game (Bloxeed, Columns): reprogram ROMs → another game, simple (close to an arcade Mega Drive repro).
  • C-2 game with 317-0xxx: conversion possible with the correct protection chip/table; without it, the game won't boot.

Where to read more

Sources & attribution

Review & corrections

How this space is used

Spotted a wrong value, an outdated procedure, a chip reference that does not match your board? Say so here, with what you observed (model, board revision, serial number, measurement). Every report is cross-checked against a source before anything changes — an unverifiable correction is published as “reported by …, not cross-checked” rather than silently applied.

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