More Games, Controllers Supported by Saturn MiSTer Core

The Saturn core of the MiSTer FPGA got a significant update a few weeks ago to increase game compatibility followed by a smaller update to improve support for controllers.

Developer Sergey Dvodnenko, aka SRG320, published new code Nov. 16 on his Github that made the core’s hardware emulation more accurate. He detailed the various improvements on his Patreon page:

• CPU:
  -fix DIVU busy (Fighting Vipers hangs)
  -fix ADDV/SUBV opcodes
  -fix interrupt accepted timing
• SCU:
  -fix DSP DMA end (FIFA Soccer 97 hangs)
  -fix DMA writing to BBUS (Sky Target, perhaps some other games)
• VDP1:
  -fix RAM readout by CPU (Cyberia)
  -fix User Clipping (P.T.O. II menu)
  -fix vblank erase (Street Fighter Alpha)
• VDP2: fix Rotation screen cell hflip (Striker 96)
• SMPC: fix PDR registers (Mansion of Hidden Souls)
• CD:
  -fix command/response flags (Striker 96 hangs)
  -SH1 fixes
  – fix WRAML access timing (P.T.O. II)

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.

Users on that server reported quite a few games that worked for the first time with the core, including Virtua Fighter Remix, Pandemonium, Contra: Legacy of War … and Shiro favorite Mr. Bones.

Awbacon, who runs the Video Game Esoterica YouTube channel, made a video last week showing off the newly playable games.

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[Edit, Dec. 15] Awbacon uploaded a new video showing even more games working on the latest Saturn MiSTer core, including the aforementioned Pandemonium as well as Shin Shinobi Den, Baku Baku Animal and the English localization of Sakura Wars:

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One thing to keep in mind is that the core may run better on newer revisions of MiSTer RAM — namely, version 2.9. A user named Kubo said there was a noticeable improvement when upgrading from version 2.4 RAM:

“I had two SDRAMs version 2.4. People wrote here that something works, works better, etc., and for me a lot of games did not even run, I thought I had a defective DE 10 nano, but I checked on two MiSTers and it was the same. My friend made v2.9 for me and everything started working.”

— Kubo

That may be why one person reported sound effects and music working in Panzer Dragoon II while another person said that game had no sound at all.

A couple weeks after Dvodnenko’s major update, two users on the MiSTer Discord, Nolbin and Blue1, created a test build on Nov. 30 to handle various Saturn controllers. That build included the racing wheel, the Mission Stick and the 3D analog controller in addition to a standard digital control pad.

Nolbin pointed out that analog triggers and throttles don’t work yet, since analog triggers aren’t yet available in the framework, but the controllers now will be recognized by the core.

“This was kind of an exercise in getting to know how the Saturn handles controllers before I try to help Blue1 with the more difficult work of getting the Stunner going.”

— Nolbin

Dvodnenko merged that controller build into the main core the next day.

Those weren’t the only updates to the core in November, as Shiro reported last month on a Nov. 8 update that improved game stability and music.

Dvodnenko released his first build of the Saturn core in May this year. After that, he updated it just once — in mid-August — over the next four months, perhaps owing to the fighting in Ukraine where he lives.

His situation may be improving, though, because he’s updated the core almost weekly since the end of September. It remains to be seen what extent the Ukrainian power outages caused by Russian missile strikes will slow his progress going forward.

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.