nesdev.org

Hello everyone,

First post here and new to NES dev (but lurking for a little while)!

I'm starting a NES project with a few others and one thing we'd like to do is to make a few simple cartridges. I just started to look into it and I'm planning to repurpose a cart and put some EPROMs in it, just to get a bit familiar with the process, the mappers, PCB types, etc.

I'm now looking for a cheap source to purchase EPROMs, ideally used (one aspect of the project is to try to make the few carts by only recycling existing parts).

I found this site: http://www.epromman.com
Is it a reliable source and do you know others that are similar?

Thanks!

(I naively checked e-waste companies but it seems that they're only focussed on rare/precious metal extraction).

For the smaller parts, 50¢ / EPROM is a reasonable price, but at $1+ / EPROM you should seriously consider new parts instead (e.g. SST39SF010 through 040).

In addition, if you're going to be developing games, I strongly recommend using EEPROMs / Flash instead of UVEPROMs: not having to wait for the eraser makes it so much nicer.

lidnariq wrote:For the smaller parts, 50¢ / EPROM is a reasonable price, but at $1+ / EPROM you should seriously consider new parts instead (e.g. SST39SF010 through 040).

In addition, if you're going to be developing games, I strongly recommend using EEPROMs / Flash instead of UVEPROMs: not having to wait for the eraser makes it so much nicer.

Thanks for the tips! I did not know it was possible to use other parts (though I assume this would require a few changes in the PCB layout no?)

One aspect of the project, which indeed involves the making of a game, relates to natural environment issues, so that's why we're investigating whether or not we could make a few carts only using recycled components, or at least as much as possible. If we succeed it will obviously be produced in a very low quantity and we will provide the NES ROM with instructions on how to make own cart, or just to play in an emu or flashcart.

I still haven't looked which mapper/game would be OK to use for this attempt, right now trying to figure out where to find second hand EPROMs.

If that fails then plan B would be to make a few PCB, in which case indeed we could use new parts, but I'd really like to try this recycle challenge first

NES games with ROMs larger than 64 KiB aren't the same pinout as EPROMs anyway, so any larger game would require rework regardless of UVEPROM or Flash.

nesdevwiki:Mask ROM pinout

Wait, the SST39SF010-040 are drop-in replacements?

No, sorry. Neither 27C0x0s nor SST39SF0x0s are drop-in replacements.

Only the smaller parts are.

(64 KiB maximum for an UVEPROM because there's no /WR pin; 32 KiB maximum for EEPROMs) )

No no no, I meant to ask if the SST39SF0x0s were a drop-in replacement for the matching 27C0x0s.

Oh. They're very close. EEPROMs have a /WR pin, whereas UVEPROMs have a PGM pin.

They're completely compatible for 128 KiB (x010) and 256 KiB (x020) parts, but 512 KiB parts differ on where they put the "A18" and "PGM" inputs.

(The SST39SF0x0 always uses pin 31 as /WR; for the 32-pin 27-series UVEPROMs pin 31 is either /PGM or A18)

OK Thanks! Now I understand your comment "any larger game would require rework regardless of UVEPROM or Flash". I had assumed that the flash option would have required more modifications compared to what was already needed for the EPROM.

So basically I would have four options in term of recycling level, without taking into account small extra components:

1. Completely recycled: old cart shell + old PCB + used EPROMs

2. Mostly recycled: old cart shell + old PCB + new MPFs

3. Slightly recycled: old cart shell + new PCB + new MPFs

4. No recycling: new cart shell + new PCB + new MPFs

Possibly another stupid question from me.

I'm looking into recycled EPROMs for this project, but in fact, are EPROMs still produced nowadays?

In which case all the "new" EPROMs on Ebay or AliExpress are in fact new old stock?

ultrageranium wrote:I'm looking into recycled EPROMs for this project, but in fact, are EPROMs still produced nowadays?

In which case all the "new" EPROMs on Ebay or AliExpress are in fact new old stock?

1. EPROMs are still manufactured and made, yes, but they're becoming less common. The same goes for EEPROMs (these are more common). Even more common are Flash chips, obviously.
2. You would need to ask the seller if the products are new or previously-used. There's no way anyone here would know the answer to that question.

The only vendor that still appears to be making EPROMs is Atmel, and they are only making OTP (windowless) EPROMs.

Thanks!