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Post by dshadoff on May 17, 2020 15:21:10 GMT
The PC Engine core was just released for MiSTer, and it's the closest match I've seen to original hardware, without being original hardware.
They have been able to measure the CPU access slots to the VRAM during HBlank, so Wonder Momo (and other games) are accurately represented. They've done an excellent job measuring hardware timing, and have passed all the tests I threw at it (including Chris' and elmer's).
The CD seek time delay is implemented, so movements match with sounds. There is Arcade Card support, as well as mouse.
And the core is open-source, so it can be examined - as well as improved.
The reason I report it here, is because there is still a certain amount of technical aptitude needed in order to set up a MiSTer for yourself (on the other hand, there are places you could just order one from, but they are backlogged).
Being an FPGA, it means that you can get no-lag output to HDMI, RGB, YPbPr, or whatever, while still having lots of options to customize things like joypads (USB joypads/mice/etc. are expected). But no interactive debugger.
I know of one bug at the moment, and there is (currently) no MB128 support. But those limitations will disappear in time.
Dave
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Post by SignOfZeta on May 17, 2020 17:32:07 GMT
CD seek times are accurate eh? That’s one of the things I noticed the PCE Mini doesn’t do right. (Switches tracks too fast). Of course there isn’t any downside I can think of but it is less accurate and even I noticed.
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Post by dshadoff on May 17, 2020 17:39:27 GMT
Yes, I made those seek time measurements publicly available back in 2018, and actively engaged Mednafen and MAME and SSDS3 people, but nobody picked it up. The only other device to use this is UperGrafx.
In a way, this is better than original hardware because it doesn't have variability in the seek time, and it doesn't re-seek. When I saw it in UperGrafx, I was struck by how it made a big difference to the gravitas of a cinema scene.
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Post by spenoza on May 17, 2020 20:37:29 GMT
CD seek times are accurate eh? That’s one of the things I noticed the PCE Mini doesn’t do right. (Switches tracks too fast). Of course there isn’t any downside I can think of but it is less accurate and even I noticed. Dave has been over the down side a few times: some titles have audio out of sync, and at least one game has a glitchy cinematic (was it Double Dragon 2 or RCR?). Sure, correct seek times means more waiting, but keeps things lined up with expectations when developers needed things to.
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Post by dshadoff on May 17, 2020 21:05:40 GMT
Oh yeah, several games have nasty ADPCM noise because the buffer gets refilled too early - before it's finished playing. These issues show on Mednafen and other emulators, but not when the seek time is accurately emulated.
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Post by gredler on May 17, 2020 21:15:05 GMT
I think this puts me over the edge, and I am going to start researching how to build one and join in. So exciting
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keithcourage
Punkic Cyborg
https://www.facebook.com/turbografxfan/
Posts: 231
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Post by keithcourage on May 17, 2020 21:45:35 GMT
Good news, I have to get a mister and try it out sometime. Up until now I've always said that wii mednafen is the most accurate pc engine Cd emulator I've used. Never noticed any weird ADPCM issues with it.
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nopepper
Deep Blooper
Posts: 21
Fave PCE Shooter: Lords of Thunder
Fave PCE Platformer: Legendary Axe
Fave PCE Game Overall: Dracula X
Fave PCE RPG: Ys I & II
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Post by nopepper on May 18, 2020 17:20:45 GMT
I tried the new core last night; made it to Maria in Rondo and the first 2 levels in Sylhpia, all without a hitch. I did not do a side by side comparison, as I only have the stock nano board with no addons (although RAM and IO are on the way) and dont have a VGA DAC, so felt it was not fair to compare HDMI to LCD vs Duo R RGB on a PVM, but on first impressions, it seems very accurate.
Just FYI, the TG16/TG16-CD core does not require any memory addon, so you can just get the DE-10 Nano board and you should be set. You just need a USB keyboard, a USB controller and an OTG USB hub (or one with an adapter).
I finally decided to plunge into the Mister to try out MSX, C64, Atari ST, Amiga, etc., as I missed the boat during the heyday of those computers, but it is fun to try out the FPGA implementations of the consoles I know like the back of my hand. So far, I've been very impressed, especially on the audio side, which I always feel like it's off when using emulators. The Genesis in particular sounds very accurate, with a clarity I don't get from my stock consoles.
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sarge
Punkic Cyborg
Posts: 104
Fave PCE Shooter: Soldier Blade
Fave PCE Game Overall: Dracula X: Rondo of Blood
Fave PCE RPG: Dungeon Explorer II
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Post by sarge on May 21, 2020 1:25:23 GMT
I keep getting tempted to jump into the MiSTer world, and this is just another point in its favor. Originally, I'd thought about getting a Mega Sg or Super Nt, but it seems like the cores for this at some point may very well match those.
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samiam
Punkic Cyborg
Posts: 100
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Post by samiam on May 21, 2020 5:00:32 GMT
Seeing the PCE hardware be more deeply understood, replicated, and ultimately preserved is a very happy thing.
Personally, I don't feel like I need a MiSTer just yet. All of my real hardware still works, and out of principle, I try to avoid dropping money on anything for this hobby that isn't going to lead directly to me playing more games. However, if things advance to the point that everything up to and including the Saturn/PSX/N64 is perfectly implemented in a single box, I'll probably buy it just for the big boost in convenience.
On that note, another reason why I'm hesitant to invest in a MiSTer now is that it's doubtful whether it will actually be able to handle those more advanced systems. Out of curiosity, does anyone have a ballpark estimate for the number of transistors in the PCE's various processors?
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Post by dshadoff on May 21, 2020 5:29:58 GMT
I just committed initial Memory Base 128 support to the core tonight (this is another "first", that emulators don't have).
A couple of the ADPCM noises if CD seektime aren't supported include: - F1 Team Simulation, noise at startup right after the car horn - Downtown Nekketsu Monogatari - with text set to high speed, go into the bookshop in the first town and leave right away; the ADPCM will continue to speak too many phrases - Brandish, opening cinema about 3 minutes in, the sorceress creates a ball of lightning - noise (not normal lightning sound) is generated.
Mister does an excellent job with PC Engine, as well as consoles of that generation (including Sega CD). It's also descended from the MiST project (but on a larger FPGA), so it has excellent support for many arcade boards and early computers, including the Amiga (Minimig). Several of the arcade boards are cycle-perfect (although not are).
As for the future of this FPGA board, the PC Engine core takes up almost exactly half of the FPGA resources. From a resource point of view, PSX and Saturn are plausible, though they could be tight. Nintendo 64 is probably not likely, due to its use of RDRAM and high frequencies (though I might yet be proved wrong).
I understand that a PSX core is actively being developed (although it's a long way from being done), and Saturn may be in the works (but I'm not certain). In terms of the ground that they are breaking and the pace of new development, it feels a lot like MAME did back in the late 90s, where every week had some noticeable improvement.
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samiam
Punkic Cyborg
Posts: 100
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Post by samiam on May 21, 2020 6:11:14 GMT
As for the future of this FPGA board, the PC Engine core takes up almost exactly half of the FPGA resources. From a resource point of view, PSX and Saturn are plausible, though they could be tight. Nintendo 64 is probably not likely, due to its use of RDRAM and high frequencies (though I might yet be proved wrong). I understand that a PSX core is actively being developed (although it's a long way from being done), and Saturn may be in the works (but I'm not certain). In terms of the ground that they are breaking and the pace of new development, it feels a lot like MAME did back in the late 90s, where every week had some noticeable improvement. If transistor count means anything with FPGA (does it?) then an accurate Saturn implementation will have much greater needs than any of the "16-bit" systems. The 68000 CPU was named for having 68,000 transistors in it, right? Well, the SH-1 in the Saturn, which only controls the CD drive, has 600,000. The two main SH-2s surely have more. It may easily turn out that the Saturn's processors in total have 10x the transistors of the processors in the Genesis/SegaCD combo. Perhaps, much as it was with software emulation, cores for more advanced systems will only be possible on common hardware if they cut corners and allow inaccuracies. Also, the guy who just announced that he's working on an N64 FPGA core has said this:
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Post by dshadoff on May 21, 2020 12:41:55 GMT
On an FPGA, one needs to think less about transistors and more about gates - and two basic types of those at that: 1) lookup table (simulates any combination of AND/OR/NOT), and 2) flip-flop. Another type of critical resource is on-chip memory, which is usually used for high-speed operations such as video renders.
It turns out that busses and memory consume more of these resources than CPUs. And the internal framework of MiSTer (on-screen display, video generator, scalers) takes up a fixed amount on any core. Still, a pretty good Neo Geo core exists on MiSTer, as does X68000 (although the latter is still being fitted to MiSTer's framework).
And one more thing: the MiSTer chip includes an ARM processor which runs linux for support of certain operations better served by a CPU - like reading SDCard data in order to supply it back to the FPGA. In this way, the ARM simulates the CDROM drive, and presents this to the FPGA as though it is the SCSI device. So not everything ultimately needs to be 'synthesized', but everything gets an appropriate-level/appropriate-speed simulation, which should be indistinguishable from the original hardware.
I think we'll have to wait and see whether these cores are able to be fit in MiSTer. Clearly, this generation of machines will not be a 'slam dunk', and nothing later will fit on this particular chip. On the other hand, once working code is in place, a future FPGA should eventually be capable.
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Post by spenoza on May 21, 2020 12:58:18 GMT
The Saturn just has too many discreet CPUs and busses. I’m pretty sure it will require a massive FPGA.
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sarge
Punkic Cyborg
Posts: 104
Fave PCE Shooter: Soldier Blade
Fave PCE Game Overall: Dracula X: Rondo of Blood
Fave PCE RPG: Dungeon Explorer II
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Post by sarge on May 21, 2020 23:43:26 GMT
Honestly, that's one of the reasons I've held off a bit. At some point, I anticipate there will be another, more capable FPGA and cores will get ported. Who knows how long that will be, though?
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