I've been thinking of things to add to my EXP board proj3ct, and something like this would also be possible, albeit within certain limitations. You could probably route a simple mapper design via the EXP/CPU pins, and of naturally, you can add additional RAM there as well.
I pondered this as a possibility on my concept deaign, and how it could be useful, so I'd like to chat with you about it for the EXP slot designs...
(I'm also curious about adding custom GFX chios via the EXP bus, or a co-processor or sorts.)
The problem here is that just building a card to do this isn't cost-effective, as it doesn't do enough. I will consider the possibilities though and discuss it with those involved. The beauty is that you can fit a lot on a multi-layer SMD board that can live under the door on the Toaster NES.
I'm also curious what i could do with the SNES/SFC EXP port. as the Satellaview uses it, and the vapourware SFC-CD system would have as well, so it might be cool to muck about with it after I get something ready to ship for the NES port.
(Is the SNES/SFC EXP port pinout in the FAQ or Wiki? I need to check...)
Once I have the connectors, I'm thinking of sending a free developer board to the top guys here (Memblers, Tepples, Bunnyboy, Kevtris, etc.) so that we can all work together to make something mondo-cool. I don't have any problems sending out developer board samples of this kind of thing, as the more people involved, the better the end-result. using t
My first product he EXP slot will simply be the 'NESpander' (TM), which will add the Famicom DA-15 port to the NES and will have connectors for developers to use (via ribbon cable connections).
Ideally, I'd like to add a custom audio component to it, something like the FDS FM chip or the VRC-6. My goal is to have a custom FPGA that is its own sound component, but emulates both the FDS and VRC-6 (maybe the VRC-7 too) on the EXP slot.
This way, developers who want to make new games with extra sound can make games that use special sound expansion via this component, without having to add the chip to each cartridge. I think there are enough data lines to achieve this, but It'll take some work.
I have some more samples on the way to me (at l3ast, they are supposed to be on the way to me), and as soon as the final measurements for tooling are ready, i will pay the balance due on the setup fees and do a full run of the connectors.
The R&G Guy at the firm making these for me, who had done the initial tooling setup was in a car accident last week, so it's being handled by a new guy (his supervisor, I think) and I have to wait until Monday to check up on the status of the project.
Don't get me wrong: I have all the sympathy in the world for him but it irks me that the Universe is sticking it in me once again. Hopefully I'll have my new samples this coming week and can make a more reliable board. When I have it done, I will see about doing a YouTube video so you can see how it works.
Just don't expect The Mona Lisa...it'll look more like a Picasso until i do a masked PCB or even a copper-clad... The present one is jumper-wired and has ribbon connectors to allow for mucking about with it.
I also have to UPS off another NES, as I only sent them the logic board, but in order to make sure that the connectors are the right height, I want them to measure it from the recessed area of the case. The idea here is to make a PCB that fits perfectly *inside* the NES under the door so that I don't need to make a special case for it.
I am taking my time to ensure this is
perfect the first time, as any changes would be $1000 in retooling per change.
I've also considered ordering empty cases from that 'Generation NEX' clone system that looks like a NES toaster and using them to make my 'UnderDeck' (TM) module, which would tack under the NES pretty nicely and save $5k to $10k in custom injection moulding.
Doing it right, it would be possible to use the front-loading slot for additional expansion (via cartridge-type devices) too, which would be bitchen!
If you want to experiment with using the EXP port to achieve your goal, send me a PM and we can talk about it. I have a preliminary boa4d that I made to plug into the EXP slot with the DA-15 connector, but it is a bit flaky, as I had to modify the connectors, which is where the extra tooling costs come in.
Anybody that wants to get a prototyping board for the NES EXP slot should let me know in advance, so that I know how many to mask. I'm thinking of making ten to twenty, initially.
I also need to see about getting some new CAD tools... I want something that routes traces and layouts automatically that is simple to use for my webtablet (running XP). Until now, I've been totally Mac OSX, but I know there are better tools out there for Windows than for OSX. Suggestions?
Anyhow, to the original poster: If you are interested in collaborating, I can incorporate your ideas on the NESpander (TM), so let me know if this interests you, and what your goals would be.
Here is a pinout of the port for you, in case you don't know what it's all about:
http://wiki.nesdev.com/w/index.php/NES_ ... ort_pinout
-Xious