a classiccmp electronics project?

From: vrs <vrs_at_msn.com>
Date: Sat Jul 31 13:17:58 2004

From: "Joe R." <rigdonj_at_cfl.rr.com>
> For one thing the parts used in the HP 1000 are 25 to 35 nS parts. Also
> the enable and other control lines are very different so you'd need a fair
> amount of glue chips and probably a buffer.

> >(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.)
>
> The ones in the HP 1000 are 4 x 256 and are sixteen or eighteen (I
> forget which) pin .3" wide DIPs. Al has pins out for some of the different
> BiPolar PROMs on his site. I think they're under the games machines
> section.

OK, that helps a lot to get me on the same page.

Can you use the 74S571? Those appear to still be available from JameCo
(part #48910) at 35ns address-to-data, 25ns enable-to-data. They are 512x4
16 pin DIPs. $5.69 qty 1, $5.49 qty 10. Haven't found them elsewhere,
though.

Not knowing what I am looking for, I wasn't able to find the pinouts on Al's
site, however. Can you provide a pointer or at least a part number?

> There's no room for a duaghterboard to mount on the HP 1000 card.
> You'd have to mount it elsewhere and cable over to it.

Wouldn't that cost you a few nanoseconds just in the cabling? ISTR cable
delays measured in ns/ft.

Thanks!

    Vince
Received on Sat Jul 31 2004 - 13:17:58 BST