a classiccmp electronics project?

From: vrs <vrs_at_msn.com>
Date: Fri Jul 30 20:21:35 2004

> >I must not be getting it, somehow.
> >
> >Why can't you just use a 45ns or 55ns 27c256 or 27c512 and swizzle the
> >pinout? These are around $3 per chip, and seem to meet the requirements.
> >
> > Vince
>
> Hi
> I did some searching on the web but never found any
> 27c256's faster than 70ns. I did find 27c512's and 27c010's
> at 45ns a couple of places.
> Dwight

(Looks again.) I found 27c256 and 27512 at 45ns at Digikey, and 45ns 27c512
at JameCo. Mouser also has the 45ns 27c256, but only has 55ns 27c512. (Are
you in the states?)

So, do these meet the requirements? (Seems like you could even burn several
different images into the chips and use a DIP switch to select which image
using the high address lines :-).)

Also needn't worry about holding reset, or batteries going dead, or a big,
complicated daughter board?

(I don't know the specs for the bipolar ROMs being replaced. Someone
earlier said they were 50-60ns. I am assuming they were also fairly small
(logically, if not physically) compared to a 27c256.)

    Vince
Received on Fri Jul 30 2004 - 20:21:35 BST