sd2snes
sd2snes copied to clipboard
mrehkopf
256mb S-DD1 Rom support
Heya! I'm making a hack of SMW, and i need to use a large S-DD1 rom. These are currently unsupprorted, even though they SHOULD run perfectly fine on real hardware
I'm afraid that 256Mbits is out of reach, there is only 128Mbits of RAM on the sd2snes/fxpak.
This seems oddly familiar. Like ... something I read somewhere close to 15 years ago.
Oh yeah, now I remember. :-) Back then, it was a cool idea, and very impressive.
In this day and age, though? We've had a complete and working MSU-1 design offering even more ROM space (like, 4GB IIRC) for years now, which has rendered the S-DD1-based approach completely obsolete.
Please close this.
Oh dear 😅 Is there any documentation on that? I found a pinout showing 2 ROM select lines and 21 (maybe 22) address lines, amounting to a total of 16MB addressable space.
Oops, missed @Ramsis-SNES 's reply in the meantime. ;) I was referring to this one: https://github.com/mrehkopf/sd2snes/issues/263#issuecomment-2440113953
@mrehkopf OP probably got the number of 256 MB from this post, neglecting the fact that Near was talking about a possible change to the S-DD1 software implementation in bsnes, not actual hardware specs. ;-)
Hmm, possibly. I guess the internal registers would support such storage sizes. An obvious advantage of S-DD1 (SA-1 too) is zero-latency random access. MSU1 forces you to wait a few ms for the SD Card every time you need to read non-linearly. (I wish emulators were more faithful in that regard, they usually just stop emulation and prepare data synchronously, software won't ever see a busy flag set...)
An obvious advantage of S-DD1 (SA-1 too) is zero-latency random access.
True. Then again, what purpose other than video (which MSU1 handles perfectly well) would OP need 256 MB of ROM space for? In a Super Mario World hack, of all things?
Anyway, I'll be more than happy myself to see something cool implemented within FXPAK hardware limitations (so no 256 MB support obviously) ... Feel free to let me know if you need any of smkdan's video ROMs for research purposes. :-) I just tested the "fzeroxvid" one on firmware v1.11.0, but all it produces is a black screen ...
I would like them
Heh, gotcha :p
Here you go:
fzeroxvid.zip vidtmnt.zip vid32khzstereo.zip novideo.zip --> This last one actually works on FXPAK! As the name says, it has no video though, just SPC700 audio (the intro song from Lunar Silver Star Story). blargg once made a similarly impressive thing using Eine kleine Nachtmusik by Mozart ...
Can't be bothered with the Lunar ROMs, the last (and "perfect") one has a mirror link in the thread that's still active though. :-)
For the record, I just tested the old video ROMs above on firmware v1.11.1rc4, and I'm happy to report that they work basically flawlessly.¹ This is super-awesome, thanks a lot, @mrehkopf! 🥇 :D
This issue truly should be closed now.
¹ vid32khzstereo seems to be audio-only, too (just like novideo/vidbig), plus I only got it to play correctly the very first time I tried it. After that, it would glitch out every time with loud hissing and crackling noise drowning out the audio track itself. However, this is most likely a programming issue and not related to ROM mapping (otherwise, the ROM still wouldn't produce any output at all, and certainly wouldn't have worked correctly, ever).
Closing since the original issue can't be fixed as 16MB is the physical hardware limit.