MiSTer FPGA Forum

I was going to post this under the NES forum, but after reading on Wikipedia, I decided these should fall under the arcade section of MiSTer.

Is anyone working on or planning to work on VS. System and PlayChoice-10 arcade cores?

Roms from VS. System can converted to play on NES Core

PlayChoice-10 games can already run without any modifications in the NES core. A PlayChoice-10 is really just a RGB NES managed by an additional Z80-powered system on top of it. I don't think there would be much point in a PC-10 core, unless someone REALLY wants that second screen UI.

True Vs. System support in MiSTer would be interesting though, since it deviates further from the NES spec (different palettes, different inputs, and a few other things). Probably doesn't need a separate core though.

That does raise an interesting question... could MiSTer support both displays? Some of the things that I wonder about on the platform are the primary and secondary side of the VS PCB. VS Super Mario Bros only will run if it is installed on the primary side, as there is some unusual memory sharing/IRQ mechanisms in place, and the game is aware of this and only works on the primary side.

With the exception of flipped 1P and 2P locations in the memory map, and then select/start corresponding to a couple of the 1P-4P start buttons, it would be largely doable. I know about these two issues, as I have burned some NROM NES games and run them on VS hardware. (NES Balloon Fight is better than VS Balloon Fight, as two players can use the same side of the machine.)

I would offer up my services to verify behavior against real arcade hardware, as I have a LOT of VS hardware. Several revisions of the PCBs, quite a few ROMs with the capability to burn anything that is missing, and almost every variant of the PPUs. I helped a user named Lidnariq over on the NES dev forums a while back iron out a few things that hadn't been documented that well by running some custom tests a while back.

As others have said, it's basically done already. The things that I think would make this particular project fun are the following items:

• Adding "dual screen" support, either by finding an actual way to output video to both analog and GPIO connectors, OR putting both screens side-by-side vertically on the frame buffer
• Adding the capability for the Playchoice 10 timer to be output to the GPIO, so that someone could hook up an actual LCD timer like the original
• Come to think of it, has anyone attempted to implement the arcade PPUs' logic in FPGA? That in itself would be interesting

I keep thinking I'll get around to cutting my teeth on some VHDL, but work keeps me just busy enough that I never feel like I can sit down and spend any time on it. If anybody wants to jump in on it, I'd love to help out in whatever way you would need.

I found this thread as I thinking along the same lines with the SNES based Nintendo Super System arcade hardware. Would love to see this implemented for VS. Super Mario Bros. (I know there is a rom converted for NES). But would be great to preserve (and enjoy) this piece of Nintendo history.

Gehstock wrote: ↑Wed Jul 01, 2020 7:41 pm Roms from VS. System can converted to play on NES Core

Do the color palettes look OK? Would you just change the filters?

Personally, I see a common MiSTer philosophical issue at play here: is the goal to be able to just “play the game”, or is the goal to be able to accurately reimplement the game PCB such that a MiSTer could (relatively) easily be used to replace an original game PCB in an actual cabinet?

In *my* ideal world, the latter would be the ultimate goal of every core effort. The former is an *awesome* step toward it, but I’d love to see the latter always kept as the ultimate goal. Why? Because the ultimate experience, IMHO, is playing in an actual cabinet. On top of that, the core plus proper hardware can also now be used to repair games with dead PCBs accurately. Sure, in theory you can repair any PCB, but these days that’s getting to the point of requiring custom hardware to be reimplemented since custom ICs are dying and NLA. I’d love to just be able to take a MiSTer, make a harness adapter, and be done with “original” hardware in those cases.

I mention this here, in particular, because PC10 and VS hardware has become particularly hard to find someone to repair boards, and Nintendo did use a bunch of custom chips. And the ideal PC10 is really a PC10 board with an NES cartridge adapter *and* an NES multi-cart, which all gets quite unwieldy. A single MiSTer would be way easier to manage, to be honest.

All that said, this is all how *I* would like to see things done when in reality what matters is really what the people DOING THE WORK want to see done. So consider this a humble request if you’re an actual MiSTer coder reading this.


—Donnie

I agree completely with djb_rh, that in *my* ideal world, accurate re-implementation should be the ultimate goal, for all the reasons stated.

This goes hand in hand with "just play the game". To 'play' a Playchoice-10 isn't the same 'experience' as simply playing the ROM on a NES. Yes I *do* *REALLY* want that second screen, because that is part of the whole experience. Much like the whole pi emulation vs hardware recreation/simulation debate... if you've never 'experienced' the original you won't know the difference, BUT there is a tangible difference in the experience.

Probably preaching to the choir or dead air, but wanted to add my $.02. Like others have stated, I'd love to help out and keep saying I'll learn some vhdl, but that's not realistically feasible for any time frame anyone here would care about.

Well, in fairness, while I agree that it would be MUCH better to be able to support the two screen PC10, it’s worth noting that the second screen LITERALLY does nothing useful on any but, what, ONE game? And there are single screen PC10’s (with a TOTALLY different motherboard, but very similar architecture). I’ve got one, and did that for my own arcade just because I didn’t see any purpose to keeping two CRTs working when it only really uses one and there was a single screen version anyway.

If the author(s) of the cores don’t care to go this far themselves, well, it’ll probably take someone else who just cares and has the ability -or- someone who wants to sell harnesses and MiSTers as PCB replacements for arcade cabinets to do it or fund it.

FWIW, doing harnesses for these would be pretty easy and would work for a LOT of different Nintendo applications. Conversion single screen PC10 harnesses are pretty much a DK harness with stuff added, which works for a lot of other games, too. So the same single product could be useful to replace PC10, VS, DK*, etc. It’s also easy to make the same harness *also* have traditional NES controller plugs and let people who want to use NES controllers in their cabinets. I’m doing that in my PC10 inside the coin door. Also just keeping a light gun in there instead of going with the huge chain and whatnot like arcades had since I don’t need a home version to be as durable.


—Donnie

Gehstock wrote: ↑Wed Jul 01, 2020 7:41 pm Roms from VS. System can converted to play on NES Core

This isn’t true for all games. Besides the palette differences, dip switch settings, etc some games require what would basically be 2 NES cores with a shared memory. Balloon fight is one example. A VS core would be a good addition to Mister and make more sense than doing Playchoice first.

I would also like to see an authentic PC-10 implementation supporting dual-screen output and the ability to actually select between 10 games via the menu.

This top screen may seem like it is doing nothing but what you've missed is a huge area of nostalgia for PC-10; this top screen is active even without crediting the machine. You could interact with an arcade machine in a meaningful way, learning about each game, taking in tips & tricks etc before putting in your first coin (or even after you'd spent your last).

The attract mode on a dual-screen pc-10 is pretty powerful when you consider that both gameplay and manual are together on display. Don't underestimate the role the second screen plays for these machines!