Re: Using 28F256 in a 747 instead of 2732A??????????

["Shawn R. Lin" <slin01@mail.orion.org>]

"Andrew K. Mattei" wrote:
> 
> And I don't know if they ever made 28F32's (or even 64s)... Smallest I
> recall is the 128's... (again, 28 pin... Of course, you could kludge
> together an adapter that moved the pins around from the 28 pin to the 24
> pin, but that would get kinda funky... Doable, but funky...). I built the
> PLCC to DIP adapter for my EPROM programmer that way - 32-pin solder tail
> PLCC going to wirewrap 32-pin DIP. Took about an hour...

There are non-flash EEPROMs down to 16kbit, I think Microchip Technology
makes a 28C16 and 28C64, but they seem to have skipped over the 28C32.

> I can't even find PLCC Intel AN28F512's anymore, other than the end of life
> top dollar vendors...

Anything smaller than 1mbit seems to be pretty rare nowadays.  A lot has
changed, I remember 5 years ago I think a place called JDR Microdevices
used to list a whole bunch of 28Fxxx Flash EPROMs in their catalog.  Now
I flip through Digikey's catalog and see only 1mbit or larger flash
devices are available.
On the other hand, I think 28C256 should be readily available to replace
the 27C256.

> And as for 28 vs 29 prefix, thought that was 12V programming on the 28's
> (just like EPROMs), 5V on the 29s... Pretty sure there's a difference,
> though...

Yes, you're right.  Sorry, I knew all this stuff 5 years ago and have
forgotten.  You're right about the voltage on the 28 and 29 series.  28
series are bulk erase, and 29 series can do sector erase.  28Cxxx and
29Cxxx are probably standard EEPROM and not flash.

-- 
Shawn Lin
http://www2.cybercities.com/g/gmwbodycars/
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