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tom1000000
July 25th, 2014, 02:53 AM
Hi,

Thank you to ChrisCwmbran for writing a really good intro to EPROM programming.

I have some real newbie questions about EPROM programming.

1) I am guessing that different companies manufactor the same standard EPROMs and so they end up with similar names.
Could I assume the following are all "pin compatible" and all would work in the same boot rom socket: TS27C64A, M27C64A, WS27C64, AM27C64 etc

2) How do I know exactly what eprom I should buy for a specific NIC?
I have a Kingston KNE20T PNP NE2000 ISA network card.
It looks like a 28 pin DIP Boot ROM socket.
What kilobyte size Boot ROMs does it work with?

3) Is it safe to say that the vast majority of 486 motherboards / Pentium I / Pentium II motherboards, use the same standard 28 pin DIP ROM socket for the BIOS?
So if I buy an EPROM programmer, it could also be used for motherboard BIOSes?

Thanks

Chuck(G)
July 25th, 2014, 07:57 AM
1) Be careful--when you get into the 16- and 32Kbit (2 and 4 KB) sizes, particularly, manufacturers' EPROMs can have very different programming characteristics. Even in the 64-256Kbit sizes, knowing what the manufacturer expects can be important (25 vs 21 vs 12V Vpp; the exact algorithm, etc.) A good programmer should allow a selection from a list.

2) This can be a useful guide (arcade.dyndns.org/?q=node/73) However, there are some notable exceptions. For example the Motorola 68764 64Kbit EPROM comes in a 24-pin package (useful for programming IBM 5150 BIOSes).

3) At the 486-and-up stage, many motherboards used EEPROMs, not EPROMs, so while a programmed EPROM may work, that's not what the manufacturer had in mind--and such chips are programmed in-place--no programmer necessary. After that, you run into things like FWHs (firmware hubs) which integrate the EEPROM with other functions.

tom1000000
July 30th, 2014, 04:49 AM
Hi Chuck, thanks for the info. Cheers, Tom.

MikeS
July 30th, 2014, 07:35 AM
2) This can be a useful guide (arcade.dyndns.org/?q=node/73) However, there are some notable exceptions. For example the Motorola 68764 64Kbit EPROM comes in a 24-pin package (useful for programming IBM 5150 BIOSes).
Anybody else have trouble with that link?

Stone
July 30th, 2014, 08:21 AM
Yup, it's a type of dynamic DNS link and, having used a service like them extensively a long time ago I remember if you don't keep your membership with them up to date your stuff will expire and you will need to renew. Looks like what happened here.

Chuck(G)
July 30th, 2014, 08:36 AM
Sorry that the link went away. You can google for "JEDEC EPROM pinout" and see what you get.

JEDEC, of course, is the ultimate reference, but good luck navigating that site.... :rolleyes: