Date   : Sun, 24 Jul 2005 21:13:49 +0100
From   : Sprow <info@...>
Subject: Re: ARM copros, speech cartridges, real time clocks, etc

In article <1122233737.10259.94.camel@...>,
   Jules Richardson <julesrichardsonuk@...> wrote:

> > > 2.ARM7 coprocessor board
> >  
> > That would be interesting. Take this as a firm order for a Master
> > internal version please. As a point of interest, would it use the
> > Acorn Tube ULA or something different for the hardware interface?

Unlikely since I only have a few left. I'd either use a CPLD to replace the
Tube ULA functionality, or at 75MHz just process all that FIFO nonsense in
software.

> Presumably the hardware side isn't that difficult, in that it's pretty
> much the same for any CPU? (CPU, bus interface, bit of local memory
> etc.)  All the effort's really in the software side of it, both the on-
> board ROMs for the coprocessor and any application-level stuff kicked
> off from the BBC side?

There wontbe that many chips, it's true, and a good portion of the work will
be tedious software. My initial plan would be to get BASIC running so it can
be used for something worthwhile, I'm sure you folks would build on those
foundations and use it for ray tracing etc... 

> I'm not saying it's easy or anything :) 

Non trivial is the phrase you're after.

> Presumably at that CPU speed
> there are all sorts of problems that creep in which wouldn't occur with
> a slower CPU (or one more closely matched to the beeb's own)

Well remember it's only the core that's running at that speed, the ROM is
probably at 10MHz, the RAM (if external) might be a bit faster. Nothing to
worry about though,
Sprow.