MiSTer FPGA Forum

I'm more of a collector/enthusiast than a video game player, but over the years I've collected the consoles I had as a kid (SNES/SNES/Genesis/N64/Gamecube/Dreamcast) and installed RGB mods, purchased an OSSC, gscart switch, flash cartridges, etc. I've also purchased a MiSTer with an I/O board, SDRAM module, etc.

However, I've been struggling with the idea of 'perfect hardware emulation' (or simulation or whatever you want to call it). More specifically, I've been debating whether or not to upgrade to the latest flash cartridges for my original systems (EverDrive N8 Pro, Mega EverDrive Pro, etc). I like to have all the options available to me (mostly for collecting purposes) but it made my start thinking...

How close to original hardware are we when we use flash cartridges anyways?

For example, the NES cartridges have a lot of 'mappers' which are additional chips included with many games. These are now implemented using FPGA (or software) emulation/simulation.

Another example is the Mega EverDrive Pro (or MegaSD). They both include Sega CD support but the Sega CD was more than just a CD drive. It included extra processor(s) so when using these flash cartridges you are again using FPGA and not real hardware.

Lastly, the SD2SNES recently had Super Gameboy support added (beta firmware). I think this is what really started making me think about it because what is the purpose of emulating/simulating (FPGA) a Super Gameboy on an SNES? It's a great feature if you don't have a MiSTer, but it just makes me think that perhaps if I don't use original cartridges then I'm already using FPGA emulation/simulation?

Sorry for the long post ... I just wanted to write down my thoughts and see if anybody else had any opinions on the subject.

@sofakng
I'm also a collector/enthusiast like you than a video game player, especially due to lack of time, so I'd like to give you my point of view on your questions/interrogations.
I think they are really 3 categories of people involved in this.

* The real purist which will tells you that at the moment where you modify or add something not official you're not on the real hardware and they consider this as bullshit (I know some guys thinking this and I totally disagree with this vision of think but that's they choice and I respect it)

* The people like me who try to have the same felling as the original hardware with a minimum of authenticity I mean by using FPGA instead of emulation software on a PC/MAC, for which a Mister is a dream (or any other FPGA) for the reasons that we all known regarding the FPGA

* The people who don't care to see their favorite games running on their PC/MAC, they just one to have a good time like back in the day and then go back to their PS4 and so.

So for me, what you says regarding the add of FPGA in real hardware fall in the 2nd category where most of the people will be happy with it. More over it is the best way, as having all in original will cost many many much more money and is not affordable for most of us.
As you understood I'm in favor in the FPGA whatever if it is a complete replacement or and add like the cartridge or acceleration cards etc.

This is of course my point of view, I'm maybe wrong in the way that I'm thinking but this is what I think
Cheers.
Kathleen.

Without getting uber technical .. its probably best to think of FPGA as hardware.. its essentially (though not 100%) the same logic in those custom chips, extracted and re-implemented in alternative hardware (aka fpga) .. so its doing the same stuff* the same way* the original hardware did but in a new form factor (fpga) instead of (etched silicon).. FPGA is like a erasable-rewrite-able silicon chip .. are there differences, yes but for your purposes they both "twitch and respond" the same way when prodded identically.

** in many cases the fpga author has to make "best guesses" as to what the logic circuits in the original chips did to recreate them (there can be inaccurate interpretations -- hence revisions) and in other cases they have the actual VHDL used to make the chips (or someone went thru the painstaking steps to de-cap a chip, photograph the silicon circuits etched into the silicon and map them out -- by hand ) so a near 1 : 1 recreation can be made and/or upgrades or functional improvements/features added along the way .. again this is not 100% perfect description but for your purposes of trying to wrap your head around it should help.

As far as "flash" storage, its pretty much a 1 to 1 bit-copy of what was on the original medium .. if it wasn't it wouldnt work .. unless some hacker modded the game code, but thats a different discussion. My self I enjoy the experience of the game more than the physicality of it (eg boxes, original cartridges etc) .. so to me its all about the thing itself and not the packaging it comes it .. its about the recreation of the feeling of playing that game (or using a retro computer etc) again and not what its housed in.. so i am not a "collector" by any sense, but I do like to collect "experiences" just not the packaging it came with.

Btw if you want to upgrade then do it.. if it makes YOU happy then by all means do it .. its your enjoyment, no need to really justify it to anyone but yourself.

I think most similar topics are extremely subjective and a lot of opinions in regard to them are based on feelings and/or received wisdom. As such, there is no single right "answer" really.

Sometimes I like to imagine a blind test experiment, in which you'd be given a controller and display only, with a running game, and would have to guess what hardware it is running on. I think the results could be quite surprising

akeley wrote: ↑Fri Jul 10, 2020 7:56 am I think most similar topics are extremely subjective and a lot of opinions in regard to them are based on feelings and/or received wisdom. As such, there is no single right "answer" really.

Sometimes I like to imagine a blind test experiment, in which you'd be given a controller and display only, with a running game, and would have to guess what hardware it is running on. I think the results could be quite surprising

I don't think it's subjective at all. The topic title is:

Flash cartridges with original hardware are basically FPGA already?

This is nonsense. The cartridge supplying the ROM is an add on. The system itself isn't running on an FPGA is it?

I'll not be commenting further on this, it gives me a headache knowing this isn't clear to some people.

You can think of FPGAs as clone hardware. Back in the day, there were clones of the originals as well - usually for bootleg consoles and carts, or for copier devices that could save/load games into a floppy disk or CD.

If you ask me the difference between a full FPGA system running a ROM and a "real" console using an FPGA cart, if both use the same controller and display, then I would say it is the same except for the original plastic box of the console (let's ignore minor implementation details of the FPGA cores, those can be ironed out).

In theory the FPGA console can act exactly like the original hardware at a signal level (e.g. video output), possibly even using less power than the original machine. So arguably, the modern version is better at doing the same job - except it doesn't come inside a piece of plastic molded in Japan in the 1990s. At that "old plastic" stage, the collector hobby becomes the same as collecting any other toy or devices with significance to the person (either personal/nostalgia or historical), and then what has value can be very subjective.

@retrorepair: I'm not quite sure what your point is, or who you're replying to (me, or OP) so I will also refrain from reply.

@Newsdee: "Clone hardware" for me is something like Just Speccy or other chip-for-chip reimplementation. FPGA isn't that.

The point about "blind test" was that I'm pretty sure many, many people would struggle to tell the difference between FPGA and emulation (assuming a high-end emu setup with lag whittled down to minimum), not just real hardware vs FPGA.

That plastic molded in Japan, and all real the hardware which comes with it, is also completely different from an FPGA. While in that blind test the final result might be indistinguishable, there comes another set of values attached to it (these can be monetary, sentimental or something else entirely).

And so, yes, it's subjectivity all around (maybe apart from that clone thing, it's more of a semantic definition).

akeley wrote: ↑Fri Jul 10, 2020 9:15 am @retrorepair: I'm not quite sure what your point is, or who you're replying to (me, or OP) so I will also refrain from reply.

I was replying to you both. If you missed the point, I don't know how I can follow up, but I'll try:

akeley wrote: ↑Fri Jul 10, 2020 9:15 am @Newsdee: "Clone hardware" for me is something like Just Speccy or other chip-for-chip reimplementation. FPGA isn't that.

Actually, FPGA is exactly that. This is the main difference between FPGA implimentation and software emulation. The FPGA is configured in such a way to clone the original hardware on a system on a chip.

akeley wrote: ↑Fri Jul 10, 2020 9:15 am That plastic molded in Japan, and all real the hardware which comes with it, is also completely different from an FPGA. While in that blind test the final result might be indistinguishable, there comes another set of values attached to it (these can be monetary, sentimental or something else entirely).

And so, yes, it's subjectivity all around (maybe apart from that clone thing, it's more of a semantic definition).

The only subjectivity comes from ignorance I'm afraid. Facts are facts. Monitary or sentimental elements have nothing to do with the question.

It's quite simple. The answer is 42.

Sorry, but this was the first thought that came to my mind when I read the question: "Flash cartridges with original hardware are basically FPGA already?"

retrorepair wrote: ↑Fri Jul 10, 2020 9:26 am I was replying to you both. If you missed the point, I don't know how I can follow up, but I'll try:

The only "point" I thought you might be replying to was the one contained in the thread's title. Problem is, forum threads usually expand in scope, this one is no different, and so my post was referring both to OP's further musings and what other posters were saying. And these subjects are subjective, I think it's quite obvious.

akeley wrote: ↑Fri Jul 10, 2020 9:15 am @Newsdee: "Clone hardware" for me is something like Just Speccy or other chip-for-chip reimplementation. FPGA isn't that.

Actually, FPGA is exactly that. This is the main difference between FPGA implimentation and software emulation. The FPGA is configured in such
a way to clone the original hardware on a system on a chip.[/quote]

No, it isn't. I'm not sure why are you mentioning software emulation when my post was clearly refering to a 1:1 cloned/replica chip. Now this is not subjective, it's a fact and not something you can argue about. ZX Uno or Ultimate 64 =/= C64 Reloaded or Just Speccy. These products are physically different and operate in completely different ways.

akeley wrote: ↑Fri Jul 10, 2020 9:15 am That plastic molded in Japan, and all real the hardware which comes with it, is also completely different from an FPGA. While in that blind test the final result might be indistinguishable, there comes another set of values attached to it (these can be monetary, sentimental or something else entirely).

And so, yes, it's subjectivity all around (maybe apart from that clone thing, it's more of a semantic definition).

The only subjectivity comes from ignorance I'm afraid. Facts are facts. Monitary or sentimental elements have nothing to do with the question.
[/quote]
Sigh. You're still hung up on the thread's title, completely ignoring the fact I wasn't talking about that at all. Please try to read the OP's and subsequent posts and try to understand what I was referring to as "subjective" (eg, measurable latency: fact. Way people perceive it: subjectivity)

I can see where this is going though, and won't participate any further. For some reason there are many FPGA fans who perceive any kind of similar discussion as a contest, in which it has to be proven that FPGA is absolutely the best, and an only valid solution. I find it tiresome, so will pass on further replies.

retrorepair wrote: ↑Fri Jul 10, 2020 8:04 am This is nonsense. The cartridge supplying the ROM is an add on. The system itself isn't running on an FPGA is it?

I'll not be commenting further on this, it gives me a headache knowing this isn't clear to some people.

SD2SNES usues an FPGA to emulate cartridge expansion chips. MegaSD emulates the SegaCD hardware. Flashcarts do a lot more than just deliver ROM data these days.

akeley wrote: ↑Fri Jul 10, 2020 9:15 am No, it isn't. I'm not sure why are you mentioning software emulation when my post was clearly refering to a 1:1 cloned/replica chip. Now this is not subjective, it's a fact and not something you can argue about. ZX Uno or Ultimate 64 =/= C64 Reloaded or Just Speccy. These products are physically different and operate in completely different ways.

You really don't know what you are talking about.

akeley wrote: ↑Fri Jul 10, 2020 12:57 pm I can see where this is going though, and won't participate any further. For some reason there are many FPGA fans who perceive any kind of similar discussion as a contest, in which it has to be proven that FPGA is absolutely the best, and an only valid solution. I find it tiresome, so will pass on further replies.

It's not a contest, it's an effort to prevent people who know no better being confused by people who insist they know what they are talking about when they absolutely do not.

I agree there are too many people who feel this way, I just wish they were also more educated.

I think I'll stick to sharing my projects on here and keep out of general discussion, I can't read posts like this without getting a headache.

Sigismond0 wrote: ↑Fri Jul 10, 2020 1:21 pm

retrorepair wrote: ↑Fri Jul 10, 2020 8:04 am This is nonsense. The cartridge supplying the ROM is an add on. The system itself isn't running on an FPGA is it?

I'll not be commenting further on this, it gives me a headache knowing this isn't clear to some people.

SD2SNES usues an FPGA to emulate cartridge expansion chips. MegaSD emulates the SegaCD hardware. Flashcarts do a lot more than just deliver ROM data these days.

I don't think SD2SNES does anything a snes cartridge doesn't? Aside from MSU1 which is brand new. The system is still the same, yes?

MegaSD and Mega Everdrive are blurring the lines a bit with Sega CD support so I'll concede on that point. In essence though the base console is still the same hardware. Maybe we can call these "hybrid" systems.

Sorry guys ... I didn't want this thread to devolve into an argument/discussion about FPGAs versus real consoles.

I was more interested in the thoughts about using flash cartridges with original hardware and how it was related to FPGA.

The ROM loading seems fairly insignificant for this discussion and using a flash cartridge to emulate a ROM cartridge/chip seems the same as an original cartridge.

However, I'm thinking about things like NES mappers and special chips from the cartridges. Things like MMC5 or SuperFX chips. When you begin to use a flash cartridge, the cartridge is now simulating/emulating those additional chips. I feel this begins to stray away from original hardware at that point and if so, then why not just use a MiSTer to simulate/emulate the entire system?

(To be clear, this is argument/discussion in support of MiSTer; Basically I'm saying that if you are using a flash cartridge in your original system, why not just use MiSTer since you are already using an FPGA to replace several hardware chips/features...)

akeley wrote: ↑Fri Jul 10, 2020 12:57 pm ZX Uno or Ultimate 64 =/= C64 Reloaded or Just Speccy. These products are physically different and operate in completely different ways.

These are different products not because of their internal tech but because of choices made for their design. It's basically motherboard replacements (designed to fit with original hw), so perhaps it's better to compare it to the ZX-Go+?

https://manuferhi.com/p/zx-go

It basically is an FPGA motherboard replacement. I have not tested it myself, but if this FPGA motherboard is 1:1 identical in behavior to the original (or improves upon it e.g. VGA output) then wouldn't using FPGAs be the same (not better) as using pure discrete logic?

That's the key point here. If you take all emulators available for a given retro system, on average, they will be much more fiddly and less faithful than the average FPGA implementation. This isn't so much because FPGAs are some kind of magical higher standard, but because they operate specifically by describing hardware behavior - in other words, if you know accurately the behavior of the original, a 1:1 FPGA core can be done.

At the end of the day, an FPGA can simulate a single chip... but it can also do two, three, up to the entire motherboard. The logic in Everdrives could be used in a full FPGA system (it's just a module on top for handling carts, after all). It's more cost-efficient to code the entire system inside an FPGA, and it also allows for "bugfixes" down the line (which you can't do in real hw).

In software emulation my biggest gripe is that (on average) software emulation is done poorly not because of the code, but how it is packaged or people not bothering to configure it to a good standard. For example, Pandora's Boxes (bootleg arcade emu) with incorrect ARs and frameskips, or the RetroFreak/Retrons that had huge lag when turning on filters, or somebody just downloading a random emu and running it without knowing how to squeeze the best out of it. FPGAs (both Everdrives and systems) are usually much easier to setup to a good standard.

Newsdee wrote: ↑Sat Jul 11, 2020 5:33 am These are different products not because of their internal tech but because of choices made for their design. It's basically motherboard replacements (designed to fit with original hw), so perhaps it's better to compare it to the ZX-Go+?

You say tomato, I say... But the internal tech isalso different. Obviously. ZX Uno (FPGA) is pretty much ZX Go, as is ZX DOS, U64 is FPGA too. Harlequin/Just Speccy/Amstrad and other clones are not, because they do not use FPGA chips.

And you have completely missed the point of my post too. It was not about what's better/worse but about how all these discussions are highly subjective. There's no need to explain to me how FPGA works or how it os different from emulation, etc, etc - I'm quite familiar with this subject, hell, I even own a couple of these boards

But I also own a heap of real hw and use many emulators. All these other solutions also have their strong points. For some people these points are more important than the ones FPGA's have, or perhaps, like in my case, can be used interchangeably. There's nothing can be done about it because value and perception of these points differ from person to person. And that's subjectivity.

OP's question of "How close to original hardware are we when we use flash cartridges anyways?" belongs to that realm too. The answer to it is "as close as you think you are".

akeley wrote: ↑Sat Jul 11, 2020 9:08 amIt was not about what's better/worse but about how all these discussions are highly subjective (...) The answer to it is "as close as you think you are".

You are right it's subjective. My own experience is that the more one upgrades original hardware for modern comfort, the more attractive it is to have a new tech that does the same in a cheaper way. Or maybe that's just me

Perhaps objectively an FPGA flash drive can be seen as a custom disk drive... it only replaces part of the original hardware but everything else keeps running the same. It is compatible with original peripherals (controllers, CRT, etc) and it is modular, i.e. one can still go back to original carts.

If I wanted to have more, say HDMI and USB controllers, then I would need many more upgrades if I somehow wanted to keep the original CPU running the system. At some point such upgraded setups can become a frankenstein monster, then a replacement may make sense This is not just a problem with modding / flashcarts, it even happened with original devices e.g. using a Sega "tower of power" + various devices to process and upscale RGB into VGA or HDMI.

Allow me to take out my teaspoon, produce a small pot of shit and give it a thorough stir...

No one ever seems to mention that machines like the C64 had chips with analogue components (SID & VIC-II) which FPGA's can only approximate*.

*Note the diplomatic avoidance of the word "emulate"!l

ZigZag wrote: ↑Sun Jul 12, 2020 3:48 amNo one ever seems to mention that machines like the C64 had chips with analogue components (SID & VIC-II) which FPGA's can only approximate*

Those are really outliers made of unobtanium... nobody, not even Commodore, ever replicated those chips but both discrete hardware and FPGAs can interface with them; devices exist with a socket to add them on.

I don't think there is an equivalent for the topic at hand (carts for consoles), except that maybe one could, in theory, reproduce that SNES Shogi game by adding an actual ARM in it, so as to avoid having to reimplement it in the FPGA. To me either approach is still "real hardware", though.

If we want to confuse people, we can talk about the MD Everdrive that has a NES FPGA core inside it as a bonus...
https://youtu.be/JOyePyw5yfA?t=389

I just found out this article from Intel... they are showing off that their FPGA powers an exact recreation of the SID
https://blogs.intel.com/psg/fpga-revive ... l-of-fame/