I need an EPROM writer/eraser

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

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NMorgan
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I need an EPROM writer/eraser

Post by NMorgan »

Can somebody direct me to a good EPROM writer? I also need an EPROM eraser. The reason I want this is so that I can write my SMB Hack to CHR and PRG chips that I took from a SMB cartridge, then put them back into the cartridge, so that I can play my hack with an actual NES.

Please, somebody, just point me in the right direction.

Thanks in advance.
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BootGod
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Post by BootGod »

http://www.sivava.com sells an assembled Willem programmer for a great price. As for an eraser, I would have to dig to find out where I got mine from. It was ~$40 I think and it's very "homemade" type device. A "professional" one costs an insane amount.

But honestly, I would avoid EPROM's altogther. In your case, they would be nice simply for that fact that no cart rewiring is needed. But to buy an eraser solely to develop your hack is kinda extreme. If your handy with soldering at all, I would suggest you use Flash memory instead and just rewire the cart to accept them.

BTW, you can't rewrite original ROMs taken from a cart :P
NMorgan
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Post by NMorgan »

Well the only way I know how to get my SMB ROM hack onto a NES cartridge is to take an original SMB cart, desoldier the CHR and PRG chips, rewrite to them, then soldier the chips back.

Is there any other way?
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tepples
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Post by tepples »

Apparently you're supposed to desolder (no 'i'; pronounced dee-sod-er) the ROM chips and solder in DIP sockets. Then you can just unplug and replug when you want to change the program.
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Memblers
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Post by Memblers »

Erasable EPROMs have a quartz window on them, and are erased by shining UV light into them. So I'd say to not bother with an eraser for just this use. I'd say to either:

1. Finish the hack completely, and have it burned on a couple OTP EPROMs (assuming it's cheaper than a new UV EPROM) and solder it in permanently.
or
2. Find 28-pin flash chips (AT29C256 maybe?) and a couple DIP sockets. Rewire and install the DIP socket if needed so it matches an EPROM pinout, then you can remove the chips and erase them with a programmer.
CFB

Just to answer your question

Post by CFB »

I would get the Pocket Programmer 2. It will burn all the EPROMS that the NES as well as Playchoice would use. As for a UV eraser, you can get the Dataerase. Just look on ebay. I spent about $50 for both. Good deal since the Pocket Progammer is $150. Otherwise, you can always get the Willems EPROM programmer.

If you are looking for a EPROM programmer, make sure you can get a programmer that can burn 2764,27128,27256,27512,27010,27020. Make sure it also supports the CMOS versions of the above eproms, 27CXXX (e.g. 27c128). Also, make sure the software runs on your computer OSa nd finally, make sure it support the parallel port or usb port.

My old win95 laptop runs the Pocket Programmer via the parallel port.
NMorgan
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Post by NMorgan »

What about this for an EPROM programmer.

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... RK:MEWA:IT

It looks promising, but can I get some expert opinion? This will be able to erase PRG and CHR chips, right, and then reprogram them?
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Posted with love by NMorgan
Great Hierophant
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Post by Great Hierophant »

[quote]http://www.sivava.com sells an assembled Willem programmer for a great price. [/quote]

That device seems good, but I suppose it only uses the USB port for power, not for programming, which is incredibly stupid.
Guest

Post by Guest »

I'd check and see what platform the software is for. If it's old MS-DOS code (it is on a floppy after all), you may have a hard time running it.

However, *nothing* will let you erase old PRG and CHR chips, as others have already told you. They cannot be erased or reprogrammed. You can however buy EPROM or Flash chips which *can* be reprogrammed.

You'd then:
Buy some EPROMS of the correct size (look at nesdev or google, there are several writeups on how to do this)
Desolder the old PRG and CHR chips, and *throw them away* or otherwise set them aside.
Program your hack onto the clean, erased EPROM you bought)
Solder the eproms in (if your hack is finished) or solder sockets in
Place the eproms in the sockets, and leave the case off while you test.
Tada

Flash is nicer in that you can erase it using your eprom programmer, but it does not have the same pinout as EPROM or ROM, so you have to rewire the board a tiny bit (usually just a few lines). EPROM works directly, but you also have to buy an EPROM eraser, or risk it and leave it out in bright sunlight for a suficient period.
Guest

Post by Guest »

NMorgan wrote:What about this for an EPROM programmer.

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... RK:MEWA:IT

It looks promising, but can I get some expert opinion? This will be able to erase PRG and CHR chips, right, and then reprogram them?
It would work for your case I guess, but the fact that it only accepts up to 28-pin EPROMs will limit you to 64KB or less. Which again is fine for SMB, but if you plan on using it for much else, that doesn't go very far. Plus this ebay one appears to work with EPROMs only, whereas the Willem one works with a LOT of different kinds of memory.
drk421
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Post by drk421 »

Just get a Willem based programmer, they work well, they're cheap, and they're upgradable.
NMorgan
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Post by NMorgan »

Isn't EPROM an acronym for eraseable programmable read-only-memory? So why can't I erase the PRG and CHR chips I found inside the SMB cart?
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dXtr
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Post by dXtr »

mainly because they ain't EPROM just ROM
Sorry for misspellings, I'm from Sweden ^^
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Post by Guest »

Because they are *NOT* EPROMS. They are mask ROMs, made by creating a mask to be used as a photolithography mask in the exposure of the final topmost metal layer on silicon wafers, and only used to make thosands of ROMs at a time.

You are *replacing* the mask ROMs with EPROMS, and I honestly don't understand why you can't grasp this. If you're worried about the cost, EPROMs are dead cheap compared to an eprom programmer, and the cost of your time dwarves either cost.
NMorgan
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Post by NMorgan »

No, I'm not worried about the cost. Where is the best place to buy 28 pin EPROMs?
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