Project: RP2C0X-XXXX, the Universal PPU Replacement

Status
Not open for further replies.

larrylemming

Member
Joined
Mar 10, 2011
Messages
246
Reaction score
3
Location
Minnesota
Project: RP2C0X-XXXX, the Universal PPU Replacement

I'm pleased to announce that I am embarking on what will most assuredly be a long, difficult, and highly rewarding project -- a Universal PPU replacement.

WHAT? What this aims to do is to be a drop-in replacement for Nintendo Vs. and Playchoice systems. All of the PPU chips effectively had the same internal architecture; the major difference was the color palette used. My replacement will have a selectable color palette to be able to support all of the different variants.

There may be a chance this could also support home consoles as well, but that's not the priority here.

WHY? Because PPU's are undoubtedly going to become harder to find and more expensive as time goes on. Also, by design, several PPU's are needed to support the full library of Vs. games. I'm not trying to undercut the market for authentic PPU's by any means -- in fact, I expect my replacement will be the same cost, if not higher, than the market value of the original chip. I simply want to offer an alternative for collectors who want to play their games.

HOW? With an FPGA. My replacement will be a single FPGA and a video DAC together on a small board that will fit into the original PPU socket. It will contain its own video cable that will connect directly to your monitor, or alternatively could plug into a RGB-to-Composite converter for display on a television set.

WHEN? I don't have an exact timeline right now, but my hope is that I can start shipping by this time next year at the very latest. This is by no means my full-time job.


Raise your hand if you're interested. :) Feedback is also welcome.

I'm relatively sure of one feedback I am sure to receive -- why not do an entire Unisystem/Dualsystem replacement board? The short answer is that I want to support Playchoice fanatics and potentially console gamers as well. The longer answer is that I might undertake such a project in the future but wanted to limit the scope of this one.
 
Sounds cool.

That's a good idea to limit your scope. With the 2A03 and mappers there are just a lot of variables. The PPU is easier then the 2A03 and really should be done first. Glad to see someone going the hardware approach as the emulation always has a few things not quite right.
 
Sounds like a great idea. May allow people to finally play copies of the ninja game as well as some of the other harder to get PPUs.

Depending on price I may be down for one or two. Especially if I can then hijack one of my other PPUs to RGB mod my NES *grin*
 
Cool... good luck! I was thinking about taking on a similar project a while back, but decided that there are way more projects that I should finish before starting another large project. I assume you've seen the work other people have done in implementing the NES and PPU in FPGAs?

DogP
 
I assume you've seen the work other people have done in implementing the NES and PPU in FPGAs?

Certainly. I could name at least 3 off the top of my head. Although I can only find one documented case of anybody who has released anything (sources, board files, etc.) after they finished. Unfortunate, really. On the other hand, there's a plethora of information about the PPU around anyhow, so starting from scratch isn't as bad as all that.
 
Fantastic! I would definitely be interested in this. It would be great if it had both the NES palette and Arcade palette since they are not the same and some NES games don't translate well to the Arcade colors. This would also make NES modding much cheaper and easier since you don't need an amp. Hopefully this will also solve the jailbar problem, as all PPUs seem to experience it in varying degrees.

Keep us updated!
 
You've definately got my attention! If it'll support Castlevania and such I'll be in for one depending on price! I hear a lot of PPUs are being taken from VS systems to use for converting NES's and Super Nintendos in some manner, so that's making them even more scarce.
 
You've definately got my attention! If it'll support Castlevania and such I'll be in for one depending on price! I hear a lot of PPUs are being taken from VS systems to use for converting NES's and Super Nintendos in some manner, so that's making them even more scarce.

The PC and Duck Hunt/Tennis PPUs are used in NES consoles to make them RGB.

If you are doing a separate video cable you might want to consider adding 30khz mode to for people who might want to make use of the VGA connector on their LCD TV.
 
GREAT IDEA!

If you could figure this out wouldn't it be a logical next step to create a VS. MULTI Daughterboard or something that runs on original PCBs?!

I love this idea. Make sure you support ALL of the PPUs, especially the one on Mighty Bomb Jack and NINJAJAJAJU or whatever it's called. :)
 
Sweet.

As far as palette goes, I'm definitely planning on throwing in the NES palette. And yes, it will have an option to scan-double for VGA users. That's pretty straightforward to do in an FPGA.

John, if I go that far, it seems like it would be more economical to bypass the original PCB altogether and design a new one that plugs into the same harness. To do a Vs. Multi would require re-implementing both the CPU and PPU... with the exception of the RAM and ROM chips, there's really not a whole lot else on those boards. :)
 
I would be interested if it were a full drop in all in one replacement along the lines of JROK's multi-wiliams SysFPGA.
 
Subscribed! I had looked into this earlier but with the the registers and finding out that the ppu was basically a processor I gave up lol.

Let me know if you want some ppus to decap. I think I have a dead 0001,0002,0003, and maybe an 0004 chips. Or if there is anything else I can help out with.

I know the 05 series returns some sort of value to start up the game but never got far enough to figure out what he values were for each game.

Ninja jaja-marukun :)
 
ERMAHGERD!!!

NERNTERND ERNERVERSERL PER-PER-YERWS!!!

attachment.php
 

Attachments

  • PPU.jpg
    PPU.jpg
    75.2 KB · Views: 454
Not to hijack the thread, but the topics are related. I will be reproing the Daughter cards for Castlevania, Dr Mario, and Goonies. In that order it will be about the same time frame sometime in the next year to have all 3 done. I hope to have Castlevania done before the end of the year. Target price of $60-80 depending on how may preorders I will get once production starts.

-Jake
 
I'm in!

Someone please explain what this means in layman's terms, because I have no idea what y'all are talking about. Ya dig?
 
I'm in!

Someone please explain what this means in layman's terms, because I have no idea what y'all are talking about. Ya dig?

This means that you can buy a replacement PPU from larrylemming, then you just need to burn you own or purchase Eproms for The Nintendo VS.Game that you want. This will enable you to play any non-daughter card VS game on a VS motherboard. I am making replacement Daughter cards so you can play the games that Require these cards, with my cards you will also need the Replacement PPU or an original. Bacisly between larrylemming PPU and My daughter cards you will be able to play 80%+ of the VS games made.

Original PPUs are becoming hard to find they make about 10 different kinds and each one only works with a select few games. The replacements would work with all or most of the game.

-Jake
 
Someone please explain what this means in layman's terms, because I have no idea what y'all are talking about. Ya dig?

The NES, Vs. Unisystem/Dualsystem, and Playchoice-10 are basically the same system. Games are *mostly* compatible between systems. They all used the same processor chip and some variant on a common video chip, called the PPU. The different variations of the PPU mainly come into play on the Vs. system, as each game needed a different PPU (check out JohnsArcade for specifics). I'm creating a new replacement for this chip that will be compatible with all of the original variations of it so that collectors don't have to horde PPU's just to play their games.

Make sense yet? :)

EDIT: And Jake beat me to it. :p
 
Status
Not open for further replies.
Back
Top Bottom