Date   : Thu, 28 Jul 2005 22:41:07 +0100
From   : "BeebMaster" <beebmaster@...>
Subject: Re: Econet-Ethernet bridge

I don't think the spare sockets on the Acorn Econet Bridge are for
"additional" RAM beyond the 8K it is meant to have.  I reckon that
the design was originally based around 4 2K RAM chips later replaced
by a single 8K RAM chip when they became more common/cheaper etc
as with the original BBC OS which was 4 x 4K ROMs and later a
single 16K ROM.

Best wishes,



Ian

----- Original Message -----
From: Jules Richardson
To:  bbc-micro@...
Sent: Thu, 28 Jul 2005 21:04:48 +0000
Subject: RE: [BBC-Micro] Econet-Ethernet bridge

On Thu, 2005-07-28 at 21:51 +0200, Johan Heuseveldt wrote:
[6809 CPU]
> Found it. It's an Acorn design with number 200,012 /C,
>                                      issue 2
>                                   and date 7 - 2 - 80

That sounds like a System part number (i.e. a eurocard), it's certainly
within the range of numbers used for the System machines. Far as I know,
it was a bit of a break from normal procedure - the 6809 *is* the CPU,
rather than being a coprocessor - so it's a bit unique as far as Acorn
are concerned.

I think the manual I have contains listings for the monitor ROM and the
board layout, but I'm not sure it contains full schematics (so if anyone
does have them still, shout - I'd be interested in a copy)


Oh, regarding the Econet bridge, yes the one I have here does have three
empty sockets for additional static RAM (actually no sockets, just PCB
traces - easy to add though)

cheers

Jules