Date   : Mon, 25 Jul 2005 23:28:48 +0100 (BST)
From   : Pete Turnbull <pete@...>
Subject: Re: [Bulk] Re: Re: ARM copros, speech cartridges, real timeclocks, etc

On Jul 25 2005, 21:35, Jules Richardson wrote:
> On Mon, 2005-07-25 at 22:29 +0100, BeebMaster wrote:
> > Multiple second processors /co-processors must have been a
possibility
> > in the long distant past as the Master Reference Manual description
for the
> > *X command seems to hint this
>
> Well I have a feeling that the Tube was designed to be a bus with
> multiple devices on it, but the reality was that it had trouble
coping
> for some reason. I'm just not sure if that was for software reasons
or
> some kind of fault with the basic hardware.

It works.  The problem is partly software, partly hardware.  Only the
Master has any software support at all, and that's pretty primitive.
 Out of the box, it doesn't let you run two at once, rather it lets you
use either an internal one or an external one.  I've had a Master set
up like that, with a 512 and a 6502.  The hardware part is down to bus
loading.  I still have a Beeb with both a 6502 and a Z80, simply
switching the power to one or the other (and doing a reset, otherwise
the poor thing gets confused).



-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York