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PostPosted: Mon Dec 26, 2005 3:07 pm 
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Hi,

I've been reading up on things for a long time, and decided to try to make an NROM devcart. I ordered a Willem programmer and some 28 pin IC sockets so I can take the chips in and out easier. Today I desoldered the PRG/CHR chips on an SMB cart.

Now I'm trying to decide what type of chips to buy, EEPROM or flash memory.. my question is this: Will I be able to erase the flash memory with my Willem programmer?

Right now I was looking at purchasing some 29c256's. I saw that the Willem supports them, but I'm not sure about the erasing procedure.

Thanks,

NC


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PostPosted: Mon Dec 26, 2005 6:33 pm 
You will need a UV eraser for the EPROMs. Look for a used one on ebay. I have a dataerase which has a plceholder for 4 EPROMS. I have a big one that can erase 30 - 40 at a time.


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PostPosted: Mon Dec 26, 2005 6:44 pm 
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chimyfolkbutter1 wrote:
You will need a UV eraser for the EPROMs. Look for a used one on ebay. I have a dataerase which has a plceholder for 4 EPROMS. I have a big one that can erase 30 - 40 at a time.


Thanks, I figured I need one of those for eeproms.. do you know what I would need for the flash memory?

NC


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PostPosted: Tue Dec 27, 2005 3:45 am 
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Willem programmer can program and erase flash and EEPROM (if it's a supported chip), they're made to be erased electrically (that's EEPROM, not EPROM). Just for reference, usually (not always) the part #s start with:
27x = EPROM
28x = EEPROM
29x,39x,49x = Flash


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PostPosted: Tue Dec 27, 2005 5:52 am 
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I compared the data sheet for the AT29C256 to the EPROM pinout sheet for the 27C256, and they look similar. The only difference is that the FlashROM has I/O where the pinout for the EPROM says D. However, since the I/O says "d"ata in/out - can I assume that the D stands for data?

If that is true, are the pinouts similar in every size (256, 512, etc) for each type of chip: E-, EEPROM, and flash?

I just want to make sure the pinouts are the same before I order them. Again, thanks for the information!

NC


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PostPosted: Tue Dec 27, 2005 7:16 am 
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Nice find, it took me a moment to actually locate the pinout for the DIP version of that chip (most of it's datasheets seem to show only PLCC and TSOP).

Yep, the D just stands for data. I/O is the same thing, just that EPROMs do a lot more output than input, heheh. Looks compatible.

I think 29F020 is also compatible with 27C020. Seems like all the other sizes aren't, since flash/eeprom chips need a /write signal. 28C256 has a different pinout, so I'd forget about eeproms and stick with the 29C256 if you can find those somewhere.


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PostPosted: Tue Dec 27, 2005 7:29 am 
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Wonderful, thanks again.

NC


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