Date   : Sat, 16 May 2009 23:21:14 +0100
From   : info@... (Sprow)
Subject: Co-Processor clarification.

In article <C634F339.2D9CD%darren.grant@...>,
   Darren Grant <darren.grant@...> wrote:
> Just trying to better understand how a BBC 6502/65C102 co-processor works.
>
> Presumably MOS remains on the main processor, but I'm not quite sure about
> DFS/ADFS seeing as how DFS is accessing the hardware would it be running on
> the co-pro ?

ADFS or DFS (and indeed any service ROM) remains in the host.

> Because the co-processer has its own RAM it can run at any clock speed and
> would just have to wait to write out via the tube to the slower host.

Any clock speed.

> Will any software run on the 6502 co-pro or does the software have to be
> written to be able to communicate via the tube ?

No special effort is required (as long as only documented OS calls are used).
 
> Is there some sort of basic of firmware on a ROM on the co-processor that 
> is responsible for routing requests the the host ?

Yes - a tiny 4k EPROM in the case of the 6502 coprocessor,
Sprow.