Is there a way to mod the NES to somehow support CDS?

Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.

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tepples
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Re: Is there a way to mod the NES to somehow support CDS?

Post by tepples »

nocash wrote:
Fisher wrote:Flashcarts here costs an arm and leg. A NES CD-ROM or any other option that could be built cheaper would be awesome to people like me.
What do you pay for a 8GB SD card, compared to a box of ten 800MB CDR's???
With ten CD-R discs, you could sell a physical copy of your work to ten people, so long as it fits on one CD. With one 8 GB SD card, you can sell a physical copy of your work to only one person.

To cut down on the cost of RAM and mapper hardware on the system card, one might limit the system card's mapper compatibility to only homebrew games that are ported to the CD. This could mean 128 KiB PRG RAM, 32 KiB CHR RAM, and a roughly MMC3-class mapper. Obviously Magic Floor would be among the first victims, seeing as it's the only game for Super Disc.
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Fisher
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Re: Is there a way to mod the NES to somehow support CDS?

Post by Fisher »

nocash wrote: What do you pay for a 8GB SD card, compared to a box of ten 800MB CDR's???
I checked and found that a box with 25 CDs is R$25,90 + R$21,90 shipping, a total of R$47,80 shipped.
A 8GB mini SD card is R$29,00 + R$23,90 shipping, a total of R$52,90 shipped.
Almost the same price.

Since all (or almost all NES games) should fit on a single CD-R, if the interface to NES is cheap and simple enough to someone with a little electronic experience (like me) to built it at home that would be a good deal!

A chinese everdrive knockoff is about R$699 shipped. I can try to buy direct from some distributor, but the risk of simply not receiving + the taxes are pretty high.

Again, I'm not wanting to be a baby cry here, but I sincerelly hope these prices and taxes become smaller in the future.
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tokumaru
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Re: Is there a way to mod the NES to somehow support CDS?

Post by tokumaru »

Don't buy Everdrive knock-offs, ever. They're not just inferior quality replicas, they have compatibility issues and won't function with a lot of mappers. For a price lower than that you can get an original one directly from krikzz.

Krikzz usually offers discounts on Black Friday, which's coming soon. Maybe that'll be a good opportunity to buy an original Everdrive.

I think that the most a hobbyist without advanced knowledge of electronics could make at home is a cartridge that can handle discrete logic mappers. Anything more advanced than that will require FPGAs, CPLDs and other parts that'd introduce a great deal of complexity (and cost!) to the project.
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Re: Is there a way to mod the NES to somehow support CDS?

Post by lidnariq »

The problem isn't the cost of storage. (An 8 GB SD card and some simple glue logic isn't all that different from the cost of a CDROM drive and some only slightly more complex glue logic)

The problem is mapper support. If you only want to support a limited set of games, this isn't too bad. Action 53 wouldn't be a bad place to start; it's really fairly similar to the the mapper 6 copier hardware definition used by contemporary pirates.

But the more flexible your hardware, the more expensive. The FPGA used in the everdrive n8 (apparently EP2C5?) is 16USD in qty 1 and there doesn't appear to be much of a volume discount. You might be able to use a cheaper FPGA, if you're up for designing the fusemaps for all the mappers you want to support.
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tokumaru
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Re: Is there a way to mod the NES to somehow support CDS?

Post by tokumaru »

Yeah, the mapper support is the most expensive/complex part. There's also the PCB, which probably won't be cheap for small quantities. I strongly believe that if you were to design and build your own cartridge that was as versatile the Everdrive and the PowerPak, you'd end up spending more money than those cost.

Another option is building 2 EPROM emulators (one for PRG and the other for CHR) and buying a lot of cheap NES games of varied mappers to which you can connect the emulators. Ad a few switches to each cart to control things like mirroring, WRAM, etc. and you should be able to run a lot of NES games, and even other systems if you can get donor carts for them as well.

What's the cheapest EPROM emulator one can build?
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Fisher
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Re: Is there a way to mod the NES to somehow support CDS?

Post by Fisher »

I have another idea: how hard is to mount a flash ROM on a cartridge and make it flashable without needing to remove it?
I think according with the mapper the circuit may be more or less complex, is it?
Doesn't Kazzo already support that on may popular mappers?

Edit: Oh, I forgot flash ROMs have a limit on how many times they can be rewritten.
SRAMs should be more durable.
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Memblers
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Re: Is there a way to mod the NES to somehow support CDS?

Post by Memblers »

tokumaru wrote:Yeah, the mapper support is the most expensive/complex part. There's also the PCB, which probably won't be cheap for small quantities. I strongly believe that if you were to design and build your own cartridge that was as versatile the Everdrive and the PowerPak, you'd end up spending more money than those cost.

Another option is building 2 EPROM emulators (one for PRG and the other for CHR) and buying a lot of cheap NES games of varied mappers to which you can connect the emulators. Ad a few switches to each cart to control things like mirroring, WRAM, etc. and you should be able to run a lot of NES games, and even other systems if you can get donor carts for them as well.

What's the cheapest EPROM emulator one can build?
512kB SRAM, and something like 10~12 74HC parts. In another thread I posted the (partial) schematic of the one I (used to) use, the whole thing is controlled with just a few I/O pins of the parallel port. The control section could be replaced with a $1 USB MCU these days. Not sure if 32-pin DIP-to-IDC adapters are around anywhere, the 40 pin ones are cheap though. Would be nice if it was done with NES MaskROM pinout, normal IC sockets are difficult to rewire (better to mod the board).
Fisher wrote: I have another idea: how hard is to mount a flash ROM on a cartridge and make it flashable without needing to remove it?
I think according with the mapper the circuit may be more or less complex, is it?
Doesn't Kazzo already support that on may popular mappers?
Problem is, with the "traditional" boards, the mapper registers and FlashROM are overlapped. So it depends if you can safely trash the mapper register(s) while writing flash.
tepples
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Re: Is there a way to mod the NES to somehow support CDS?

Post by tepples »

GTROM and UNROM 512 are both programmable in system. And NOR flash, the kind you need for execute-in-place, might last tens of thousands of rewrites. But if you're rewriting the entire cart, you still need some sort of device, like a Kazzo or a modified Game Genie, to receive the program and write it.
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rainwarrior
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Re: Is there a way to mod the NES to somehow support CDS?

Post by rainwarrior »

The cost of media seems like a big red herring to me. It's pretty much irrelevant how much a CD costs.

What matters is how much a device that can play it costs, and that's not even on the table. Nobody is going to mass produce an NES/Famicom CD player add-on.

How much are the parts is a little bit relevant if you wanna build it, and I'm sure it'd be a fun project for somebody, but honestly the labour you will spend on this is worth at least the cost of that imported Everdrive. (Probably much more. I definitely wouldn't even want to attempt it for that wage.)

If you want a cheap way to distribute an NES ROM, you're using it right now already. :P


(...though TBH I'd love to be proven wrong when someone comes up with a cheap DIY NES CD kit that becomes super popular.)
tepples
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Re: Is there a way to mod the NES to somehow support CDS?

Post by tepples »

Better yet watch someone come up with the ATAPI 2600.
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koitsu
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Re: Is there a way to mod the NES to somehow support CDS?

Post by koitsu »

Okay tepples, you got me to LOL IRL at that one.
nocash
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Re: Is there a way to mod the NES to somehow support CDS?

Post by nocash »

That in fact might catch fire and run for mass production.
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