Date   : Fri, 18 Nov 2005 01:07:28 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: Best Emulator??

Jules Richardson <julesrichardsonuk@...> wrote:
> This purely on the Master? I seem to recall the BBC B SCSI board being
> significantly more complex than the Master one, or at least in terms of
> chip count.
 
Early scis cards may have been more complex, but as far as the
hardware API is concerned, they are the same. Data register at
&FC40, status register at &FC41, control register at &FC42. I
think it can be done in twelve or fourteen ICs.
 
There's a circuit diagram at http://mdfs.net/Info/Comp/BBC/SCSI
 
> I believe that the SCSI controller in the Viglen BBCs is different yet
> again, plus of course Torch made both a SASI and SCSI controller for the
> BBC... so there's at least 5 different flavours out there!
 
Yep! I haven't scanned in my Torch schematics yet. I'll put them
on my "to-do" list.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
Spectrum Emulators - http://mdfs.net/Apps/Emulators/Spectrum