The PlayStation (PSX) core for the MiSTer FPGA platform has received an update, focusing on improved hardware accuracy and enhanced game compatibility. While the original core was developed by FPGAzumSpass (Robert Peip), this latest revision, largely credited to developer kuba-j, introduces several crucial fixes related to CD-ROM operation, GPU rendering, and game-specific bugs.
The improvements aim to make the FPGA core behave more faithfully to the original PlayStation hardware, restoring expected functionality in both the console’s internal systems and popular game titles.
Enhanced CD Audio and Drive Accuracy
A major focus of the update was on correcting issues related to the CD-ROM drive and audio synchronization:
- CD Audio Looping Fix: The update resolves a persistent CD audio looping issue that affected titles, most notably the Wipeout games, ensuring that music tracks correctly transition from one to the next during gameplay.
- XA Audio Synchronization: A fix for CD controller SUBQ skew related to XA audio synchronization has corrected a visual error in Captain Commando, where boss graphics now appear correctly at the end of level one.
- BIOS CD Player Functionality: The pause and resume functionality within the BIOS CD player has been fixed.
- Seek Command Management: The CD drive is now programmed to ignore the pause command during seek operations, which resolves a music looping issue in the game Duke Nukem Total Meltdown.
- LibCrypt Verification: LibCrypt Verification has been adjusted to account for a
SUBQ +2 Offset.
New “Old GPU” Emulation Option
A new feature has been added to improve graphical accuracy for certain early titles:
- Toggleable Old GPU Option: An option is now available in the misc settings to simulate the older CXD8514Q GPU used in the early 100X PlayStation models.
- Gouraud Shading Accuracy: This simulation specifically models a hardware quirk where the older GPU crops 8:8:8 bit Gouraud shading color to 5:5:5 bit before multiplying it with the texture color, which is critical for accurate rendering in titles that relied on this specific behavior.
Critical Game Compatibility Fixes
The update successfully addresses show-stopping issues in several well-known games:
- Vigilante 8: 2nd Offense (USA): The game no longer displays a black screen when selecting a vehicle.
- Disney Goofy’s Fun House: The game has been fixed and no longer hangs at the loading screen.
- Arcade Hits Wolf Fang Kuuga 2001: An issue causing the background music to stop playing during mid-stages or boss fights has been resolved.
To get this version of he core, just run the “Update All” script on your MiSTer FPGA.
[Source MiSTer FPGA Forum}