[rescue] Looking for some used EPROM chips...

Patrick Finnegan pat at computer-refuge.org
Mon Feb 2 10:18:45 CST 2009

On Monday 02 February 2009, Mr Ian Primus wrote:
> --- On Sun, 2/1/09, Patrick Finnegan <pat at computer-refuge.org> wrote:
> > Is there any reason that you don't want to use flash
> > instead of an
> > EPROM?  For a new design, I'd much rather use flash
> > over an EPROM.
> Well, there's a few reasons, and maybe partly because I've never used
> flash for anything, but I avoid them...
> 1) I have nothing that can program a flash chip. Unless there's some
> function of my PB-10 EPROM programmer that I am unaware of.

Uh, they're pretty trivial to program using self-written software and 
some sort of "user port", like a PC parallel port.  There's no special 
timing required, and the datasheet for the part should give the 
necessary details.

> 2) I've not seen DIP package 8mbit flash chips. By the time they got
> to the larger sizes, flash chips got to be these tiny surface mount
> things. I don't feel like spending tons of time trying to adapt them
> to fit in DIP sockets.

Digikey lists some 40-pin DIP, 1Mx8 flash chips.
> 3) I'm using this as a semi-permanent/permanent ROM, not something
> that I'm developing on and will need to reprogram many times. The
> quick erase-reprogram is not feature I need or care about.

Ok.  This doesn't sound like an argument for or against either, just 
that the choice doesn't matter much.

> 4) I like EPROMS :) I have all the equipment to use them, and I find
> them to be fast and efficient for my purposes. I'm comfortable
> working with them, and I know how to wire them up and can be sure
> that they'll work the way I want them to. I use them all the time, in
> all sizes, for all kinds of things. I'm just looking for the larger
> sizes right now because I need some and don't have any.

Sure, but at this point flash has been used in way more things than 
EPROMs ever have, and seems to work ok.  I just think that it'll be 
much easier for you to find some 8Mbit flash than to find an 8Mbit 
EPROM.  As well, flash generally has a much faster access speed, if 
that matters for you, and usually has the same JEDEC pinout that the 
equivalent EPROM has.  

Purdue University Research Computing ---  http://www.rcac.purdue.edu/
The Computer Refuge                  ---  http://computer-refuge.org

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