Psikyo converts (68020 / SH-2)¶
Psikyo (founded by ex-Toaplan staff) has two hardwares: a 1st generation on 68020 (Gunbird, Strikers 1945…) and an SH-2 system (Strikers 1945 II/III, Gunbird 2, Dragon Blaze…). Conversion revolves around a security value in EEPROM to reflash and the right hardware variant (PS3/PS4/PS5).
Psikyo 1st generation (68020)¶
| Block | Chip |
|---|---|
| CPU | 68EC020 (~16 MHz) |
| Sound | Z80 + YMF278B (OPL4) (or YM2610 depending on game) |
| Video | Psikyo customs (sprites, rotation/scaling) |
Games: Samurai Aces (Sengoku Ace), Gunbird, Strikers 1945, Sengoku Blade (Tengai), Battle K-Road…
Psikyo SH-2¶
| Block | Chip |
|---|---|
| CPU | Hitachi SH-2 @ 28.636 MHz |
| Sound | YMF278B (OPL4) @ 28.636 MHz |
| Media | game ROM board; security EEPROM |
Games: Strikers 1945 II / III, Gunbird 2, Sol Divide, Daraku Tenshi, Dragon Blaze, Tengai Makyou, Taisen Hot Gimmick…
The variants (crucial for converting)¶
The SH-2 comes in several hardware variants — you need the right one for the target game:
| Variant | Games (examples) |
|---|---|
| PS3 | Strikers 1945 II |
| PS4 | Taisen Hot Gimmick (mahjong) |
| PS5 | Gunbird 2, Strikers 1945 III, Dragon Blaze… |
→ A conversion assumes a variant compatible with the target game (the implementations/ROM layouts differ).
The lock: the security EEPROM¶
On Psikyo (SH-2 especially) there is a security value in the EEPROM that must be reflashed for a conversion to work. In other words, swapping ROMs is not enough: you have to rewrite the EEPROM with the correct target-game data.
Conversion = specialist service
Converted Psikyo SH-2 PCBs exist (with adapted ROM layout and mods), but this is more of a specialist job (EEPROM + layout + variant) than a mainstream procedure. Identify your variant clearly before starting.
Program EPROM, game by game¶
Size → EPROM: 256 KB → 27C020 · 512 KB → 27C040. 1st gen (68020) = 2× 27C020
(even/odd program); SH-2 = 2× to 3× 27C040. (Source: MAME psikyo/psikyo.cpp,
psikyo/psikyosh.cpp. Board view: Psikyo PCB.)
| Gen | Game | Program EPROM |
|---|---|---|
| 68020 | Samurai Aces / Sengoku Ace | 2× 27C020 |
| 68020 | Gunbird | 2× 27C020 |
| 68020 | Battle K-Road | 2× 27C020 |
| 68020 | Strikers 1945 | 2× 27C020 |
| 68020 | Sengoku Blade / Tengai | 2× 27C040 |
| SH-2 | Sol Divide | 2× 27C040 |
| SH-2 | Strikers 1945 II | 2× 27C040 |
| SH-2 | Daraku Tenshi | 2× 27C040 + 1× 27C080 |
| SH-2 | Space Bomber | 2× 27C040 |
| SH-2 | Gunbird 2 | 3× 27C040 |
| SH-2 | Strikers 1945 III | 3× 27C040 |
| SH-2 | Dragon Blaze | 2× 27C040 |
| SH-2 | Tetris the Grand Master 2 | 2× 27C040 |
The real lock = the security EEPROM
On Psikyo, conversion hits the security EEPROM paired to the variant (see the dedicated section) — reburning the program is not enough.
Converting (summary)¶
- Check the variant (PS3/PS4/PS5) and its compatibility with the target game.
- Gather/burn the target game's ROMs (variant-specific layout).
- Reflash the security EEPROM with the target-game data.
- Test (sprites, OPL4 sound).
Before / after¶
- Right variant + reflashed EEPROM: the board runs the target game.
- Wrong variant / untreated EEPROM: won't boot.
Where to read more¶
- Arcade-Projects — Converted Psikyo SH2 / PS3-5 variants / EEPROM security — https://www.arcade-projects.com/
- MiSTer — Psikyo SH-2 core (WIP, srg320) — https://misterfpga.org/
- MAME — Psikyo drivers (
psikyo.cpp,psikyosh.cpp) — https://github.com/mamedev/mame
Sources & attribution¶
- Arcade-Projects — Psikyo SH-2 (SH-2 @ 28.636 MHz, YMF278B, PS3/4/5 variants, security EEPROM to reflash) — https://www.arcade-projects.com/
- MAME / MiSTer — Psikyo 68020 & SH-2 — https://github.com/mamedev/mame
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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