Date   : Tue, 07 Sep 2004 20:27:03 +1000
From   : "Bob Devries" <bdevries@...>
Subject: Re: BBC Master AIV SCSI

Darren, is there any chance that the on-board oscillator doesn't have the
drive capability to drive the components of the SCSI card?
Or maybe there was some problem with keeping it in sync with the master?
--
Regards, Bob Devries. Dalby, Queensland, Australia.
Faith isn't faith until it's all you're holding on to.
http://e4god.com/freeblogs/bdevries/


----- Original Message ----- 
From: "Darren Grant" <darren.grant@...           >
To: "Sprow" <info@...        >; <bbc-micro@...         >
Sent: Tuesday, September 07, 2004 8:00 PM
Subject: [BBC-Micro] BBC Master AIV SCSI


> Does anyone know any ex acorn engineers ?
>
> In my attempt to build a SCSI interface for the Master I have been
studying
> reference manuals and the schematic for the SCSI board
>
http://www.microcomputer.org.uk/documents/schematics/AIV-SCSI_Host_Adaptor.p
> ng
>
> The thing that is puzzling me is that on the SCSI interface there is a
16MHz
> Oscillator that all it does is feed a 16MHz clock signal to the main
board.
> I can't figure out why they bother as the Master already has an on board
> 16MHz Oscillator. By removing the jumper on LK6 and connecting the wire
from
> the SCSI card to LK6(0) we are literally replacing the inboard 16MHz clock
> with the one on the SCSI card. Is the one already on-board not accurate
> enough or something. It is not as though the signal is actually used on
the
> SCSI interface it is a completely isolated circuit.
>
> Any ideas ?
>
>
>
>