brew-your-own-unibus boards?

From: meltie <lists_at_microvax.org>
Date: Tue Jan 20 13:37:34 2004

On Tuesday 20 Jan 2004 7:29 pm, Michael Sokolov wrote:
> Ethan Dicks <dickset_at_amanda.spole.gov> wrote:
> > Yes, but some devices are not so old and _do_ use ASICs. There are
> > some peripherals that came out at the same time as the 11/20 (~1970)
> > that they are made up of several square feet of TTL/Linear chips.
>
> Well, what I meant was that UNIBUS and Q-bus were designed to be
> implementable without ASICS using only discrete logic, and the simpler
> devices were implemented that way.
>
> > Unibus? 8640, 8641, 340, 8881, DC013 (custom DEC chip)
> > Qbus? DC003, DC004, DC005, DC006, DC010, 74LS240, 8837, 8838
> >
> > In other words, with few exceptions, *not* ordinary TTL chips (though
> > ISTR one of their busses used hand-selected 7438s chosen for low
> > (1uA?) leakage.
>
> Hmm, 74LS240 for Q-bus? It's just a standard three-state TTL inverting
> buffer, isn't it? For driver, receiver, or both?
>
> > designed-as-such bus drivers/receivers from companies like
> > National Semiconductor.
>
> Does NS still make them?

Not since I last checked.

alex/melt
Received on Tue Jan 20 2004 - 13:37:34 GMT