Date   : Fri, 23 Jan 2004 12:16:10 -0000
From   : "Dom Wright" <domwright@...>
Subject: Re: IDE Interface for BBC

Way back Philip Blundell Wrote
> On Sat, 2004-01-10 at 04:48, Jonathan Graham Harston wrote:
> > I have a bazillion IDE drives on the shelf :)  I don't know how hard it
is
> > to find suitable SCSI/SASI drives for the Acorn card, but I understand
> > it's hard to find Acorn cards, and I haven't been able to track down a
> > circuit diagram for it.
>
> I have a couple of Acorn SCSI cards here, but no schematics for them.
> The circuit doesn't look very complicated, though, so if I find myself
> at a loose end I could have a go at tracing it.
>
> I'm not sure what the situation is with drive compatibility either,
> though.

I'm sure I looked into this a few years back (and failed).  I've just given
it a go with and old Maxtor 500MB drive and remembered why I stopped.

The Acorn card seems to connect pin 34 of the SCSI bus directly to +5v
(mine is an Issue 2 card).
The Adaptec ACB4000 doesn't use this pin at all, but the other specs
for SCSI that I have seen seem to indicate that this pin should be
grounded.  Hence the power supply is shorted and shuts down immediately.

Is it worth me cutting the track to pin 34 on the Acorn board?

I'd like to give it a go, then see if I can get superform to
format the drive with 256 byte sectors, or try and write something
to do it.

Dom.