Over the last few days I’ve been looking at a variant of the Seibu protection, the ‘333’ MCU used by the later re-releases.
While the Raiden re-release on this hardware is infamous for the terrible sound hardware (a single M6295) and basically seems like an official bootleg the other game that was re-released, Zero Team, didn’t suffer such a terrible fate.
There are 2 versions of Zero Team on the revised platform, New Zero Team and Zero Team 2000. New Zero Team has the first and 3rd levels swapped for no good reason, Zero Team 2000 has the level order restored and an EEPROM that saves high scores.
The V33 platform protection actually turned out to be weaker than the regular cop protection, with many features moved from being part of the COP to being done by the main CPU, including, most importantly, the hitbox protection.
The regular Zero Team has issues with collision detection due to imperfect emulation of the hitbox protection (done by the COP) as New Zero Team and Zero Team 2000 lack this protection they actually now appear to function correctly.
In the end Olivier Galibert identified the protection on these, it’s mostly just angle calculations (a small fraction of what the original COP could do) and with his implementation of that, and my general work on the driver I think we can declare these clones as working.
I’ll cover the Raiden game later, there are some interesting talking points.