Hi Jack,
* Jack Cawkwell jack@jackadder.freeserve.co.uk [030630 22:20]:
I am having problems finding places to buy empty flash 32 pin eeprom chips, suitable for use as BIOS chips. I would like to experiment with an empty one, rather than risk permanently damaging the existing one. Does any one know a good source of supply. How do you decide what speed is required?
Where to get them depends on the number of chips you need. I've been getting them from a local electronics store and got some from old motherboards, but this is only reasonable when you need a few. Prices go down a lot if you get 50+.
Speed did never matter when I put flash chips on PC motherboards. Everything from -90 to -150 types worked fine. The only thing you have to take care about is the used voltage.
How do I go from the writing on the chip to a eeprom spec, eg
AE29f2008-12, or 28F1000PPC-12C4, or 208GH213286801SA
28xxyyy-zz types are 12v, 29 and 39(?) are 5v, 49 is 3.3v. xx is F or LF most of the time. yyy is the size, 008 and 080 for 8MBit, 004 and 040 for 4MBit, 020 or 002 for 2MBit and so on. The -zz is the used speed.
Stefan