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Nuked-MD-FPGA – Emulating Sega Mega Drive chipset using decapped chips photos
- genjii931 3y agoWasn't the Genesis dev machine a Sharp x68000?
- gbraad 3y agoperhaps among some (never heard this before), but I know people who used Amigas and Deluxe Paint.
- yakkityyak 3y agoVery cool. I suppose this means someone could wire this to MiSTer or Analogue Pocket, or are they lacking the correct fpga requirements?
- agg23 3y agoThey will both likely come in the coming weeks, based on what the creator wants and general enthusiasm. Since it hasn't been wired up to a top, the ports would likely be fairly simple.
- tails4e 3y agoIs the RTL autogenerated from the chip images? I looked at one file 68k.v and the variable names remind me of a decompiler.
- qingcharles 3y agoI wondered the same thing. Otherwise that is a lot of code to write. The type of code that will cook your brain very quickly.
- lprib 3y agoIt's probably hand written but they didn't reverse engineer the purpose of each wire, only the netlist. Some of them are labeled, eg `irdbus_normal`.
- jareklupinski 3y agoguessing since the 68k and z80 cores are not specific to the genesis, they may have used another implementation (maybe https://github.com/nukeykt/Nuked-MD https://github.com/nukeykt/Nuked-MD ?) the genesis "specific" ym* cores look a lot more "authored"; commit history shows more activity around those files too but thats just a guess... something that can generate verilog from chip images would be pretty cool...
- junon 3y agoThere are assistant tools for reversing die shots, by the way. Semi-automatic, not sure if we've gotten to the point of fully automatic yet.
- rbanffy 3y agoI can’t wait to see AI applied to reverse engineering of decapped chips. Do we have tools for exposing specific layers instead of 2D images? It would, perhaps, be interesting to go with diagonal slices as we grind the chip and, aided by exaggerated vertical features, capture the full depth on a single pass.
- retro_guy 3y agoIf you are interested in more than 2D images, you might find this article interesting. - The X-Ray Tech That Reveals Chip Designs: https://spectrum.ieee.org/chip-x-ray https://spectrum.ieee.org/chip-x-ray
- vmladenov 3y agoI’m curious how this compares to Analogue’s implementation for their Mega Sg.
- mikepavone 3y agoAnalogue hasn't given a lot of detail about how they developed the Mega Sg, but to the extent that they did any reverse engineering beyond what the emulation community had already done they seem to have used similar techniques. At one point they had an identical compat bug as in my software emulator (order that bytes were updated in VRAM was swapped causing a single-frame glitch in the bike shop of one of the Road Rash games). I don't think they were using my code as a reference, but it does suggest use of similar documentation sources or similar reverse engineering techniques. By contrast, this is the first effort (well second if you consider the nukeykt's initial C version) to try and recreate the entire system from analysis of silicon die photos. If you just want to enjoy some old games the difference is probably not particularly important, but Nuked-MD-FPGA is already passing some tests that the Mega SG does not. The screenshot in the lower right corner of the "Progress" section is a timing torture test ROM that the Mega SG fails at least 40 subtests for (I say at least because the results I've seen for Mega SG are from an earlier version of the ROM with fewer subtests).
- Cthulhu_ 3y agoI love what Analog does, I've got their Gameboy device on my wishlist. I can't yet warrant buying it since I don't actually own any Gameboy cartridges so it'd be roms and the like, but still. Have you ever been in contact with them? I can imagine your and their skillsets would be very compatible with each other.
- worewood 3y agoIf you're okay with the moral implications (I am because the original manufacturer/publishers don't make the games available anymore so it's literally impossible to give my money to them) There are cheap flashcarts available, so you can live a better experience than you ever could with the original hardware.
- mg794613 3y agoWhat is a good fpga starter board that's big enough to load this? It's not obvious from the repo as a complete novice in fpga land.
- FirmwareBurner 3y agoAFAIK, an FPGA board is not enough, you also need the "compiled netlist" from the Verilog files, clock configuration and routing info, tailored to the specific FPGA/board you choose.
- mg794613 3y agomaking notes
- unixhero 3y agoThis is such a parallel universe of computing
- gaudat 3y agoAka the software that comes with the FPGA vendor. I think Intel, AMD, the Chinese vendors and some parts from Microchip have the software available for free.
- worewood 3y agoBefore intel acquired Altera they had some free (as in beer) software for it, helped me lots in grad as I could design, verify and simulate at home.
- JohnBooty 3y agoVery interesting. I'm curious if there are any specific shortcomings with modern Genesis/Megadrive emulation that spurred this, or if this is just a pure "for the love of the pursuit" effort. I'm not sure of the exact state of the art, but I know that getting sound emulation perfectly right for the Genesis/MegaDrive has been a tricky issue over the years, even for Sega themselves. Though, my (loose) understanding is that the issue is moreso with getting the analog bits sounding right rather than the digital bits.
- joshspankit 3y agoWhile there is some amount of software emulators “it’s not quite right”-ness, this is more spurred by the general availability of FPGAs with enough resources to “become” older consoles like the Genesis/MegaDrive.
- jonny_eh 3y agoBut there already exist cores for Mister and Analogue Pocket. e.g. https://github.com/MiSTer-devel/Genesis_MiSTer https://github.com/MiSTer-devel/Genesis_MiSTer
- JohnBooty 3y agoI have never worked under the hood of an emulation project, but my understanding is that the Mister/Analogue cores are best understood as an "FPGA implementation of existing software emulation." In other words, they are not emulating the 68K, VDP, and other supporting chips on a gate-for-gate basis. They are emulating them at a higher level. With the decapping of the Genesis' hardware, it should now be possible to truly emulate them at a 1:1 hardware level. This theoretically can lead to far more accurate emulation. I believe this is a lot more FPGA resource-intensive and may exceed what the existing MISTer/Analogue cores can handle, though I'm way out of my depth here.
- CSMastermind 3y ago> I know that getting sound emulation perfectly right for the Genesis/MegaDrive has been a tricky issue over the years, even for Sega themselves I would definitely be curious to know why - the emulation of Genesis is notably behind most other video game consoles but I always assumed this was because of less interest and not because of any unique technical challenges.
- ConanRus 3y ago[dead]
- DrNosferatu 3y agoWill it run on the MiSTer? or included in that project(?) providing MiSTer for any FPGA?
- rbanffy 3y agoI wonder how interesting the Genesis VDP would be for a retrocomputer project. Is there a good detailed doc for software development? I looked around and there isn’t much I the most obvious places and formats.
- city41 3y agoThis was also done by Furrtek for the Neo Geo FPGA core for the MiSTer project.