Saturn MiSTer Core Gets PAL Game Support

Support for PAL games has come to the Saturn core of the MiSTer FPGA thanks to a new update today. The update also made a variety of improvements to the overall performance of the core, making more games work that didn’t before.

The latest version of the core, which comes in two versions for one or two sticks of RAM, can be downloaded from the “unstable nightlies” channel on the MiSTer Discord server.

On his Patreon page, Sergiy Dvodnenko — aka SRG320 — listed what he did for the update:

• SH2:
  • fix completion TAS memory cycles during reset (Virtua Cop demo freeze)
  • fix MAC instructions (Sega Touring Car Championship)
• VDP1:
  • fix draw Normal sprite (Space Jam)
• VDP2:
  • fix Line Cell Scroll function in interlace mode (Grandia)
  • fix transparent for Sprite data
• SCSP:
  • remove reset logic from memory controller (Last Bronx demo freeze)
• SCU:
  • fix DMA indirect data reads (Rabbit)
  • fix simultaneous access to ABUS and BBUS (Grandia, JP bios)
• SMPC:
  • fix timing for CKCHG/ SYSRES commands (Terry Pratchett’s Discworld)
• Add support for PAL regions.

With the ability to play PAL games now, MiSTer players gain access to the 35 games that released there that never came out in North America.

About a week and a half ago, Dvodnenko issued more fixes in a Sept. 22 update. The Patreon post for that one listed:

• SH2:
  • fix saturate mode in MULT module (Assault Rigs)
• VDP2:
  • fix VRAM reading for Normal scroll screen (Death Crimson)
  • fix background color for disabled screen (Sega Rally)
  • fix Field flag flip time (Thunder Force V, True Pinball)
• VDP1:
  • fix latch time for interlace setting
• SCSP:
  • fix reading undocumented bits of Monitor register (Code R)
  • rework memory controller
• SCU:
  • fix interrupt status register (Bug!)
• Rework sdram1 controller.
• Fix bios loading.

The last item in that list alludes to the core no longer being plagued by a problem that cropped up in the June update in which it was looking for “boot.bin” instead of boot.rom. MiSTer owners had needed to rename their boot.rom file to boot.bin to make the core work, but that’s no longer the case now that the bug has been fixed.

One thing MiSTer owners do need to watch out for is the four-chip RAM module, though. It’s not very compatible with the Saturn core, and when someone asked Dvodnenko on X, formerly Twitter, whether he could make it work, he responded “No, sorry.”

No, sorry.

— Sergiy Dvodnenko (@srg320_) October 4, 2023

Video Game Esoterica whipped up a new video today showing off the games that work now, including Grandia, Sega Touring Car Championship and Rabbit.

Dvodnenko continues to live behind Russian lines in Ukraine amidst the war there, making core updates — and communication — from him fairly infrequent.

He released to the public a playable build of the Saturn core for the first time in May last year, with a flurry of updates coming between late September and mid-November. A lull in updates after that was broken in mid-April this year, followed by an update or two each month over the summer.

If you’re interested in supporting Dvodnenko, check out his Patreon.

The MiSTer is a field-programmable gate array, a chip that can be changed by programming it to physically emulate retro video game consoles. It includes an SD card reader from which “cores” and games can be loaded.

The cores are the programming that tells the FPGA chip how to configure itself to reproduce the performance of a console. There are cores for a wide array of consoles, from the Atari 2600 to the PlayStation — and now, at least in an early form, the Saturn.