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From: grr@cbmvax.cbm.UUCP (George Robbins)
Newsgroups: net.micro.amiga
Subject: Re: Sasquatch Print
Message-ID: <707@cbmvax.cbmvax.cbm.UUCP>
Date: Sun, 7-Sep-86 02:38:20 EDT
Article-I.D.: cbmvax.707
Posted: Sun Sep  7 02:38:20 1986
Date-Received: Sun, 7-Sep-86 10:04:47 EDT
References: <225@plx.UUCP> <326@sivax.UUCP> <697@cbmvax.cbmvax.cbm.UUCP> <15575@ucbvax.BERKELEY.EDU>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Distribution: net
Organization: Commodore Technology, West Chester, PA
Lines: 46

In article <15575@ucbvax.BERKELEY.EDU> robinson@shadow.Berkeley.EDU.UUCP (Michael Robinson) writes:
>
>I am sick of this discussion of all the stupid reasons why the sidecar can't
>be placed on the top of the computer.  From the discussion you would think
>that shielded cable would have to be smuggled in from Borneo.  For all you 
>engineers at Commodore, all I ask is, if you do in fact design the sidecar
>to go on the side of the computer, that you put an edge connector, identical
>to the one on the Amiga, on the right-hand side of the Sidecar.  That way some
>clever enterpreneur (like myself, for instance) can become filthy rich selling
>little three inch jumpers to all those people out there who really want to put
>their Sidecars in a sensible location.  Or, if you prefer, I will design and 
>engineer the jumper free of charge for you (I will, of course, guarantee it
>passes FCC, assuming the rest of the Sidecar does).

I case you didn't notice, most of the ribbon cable flames were directed to
the person who wanted to attach an arbitrary length of cable, perhaps running
over the next room.  The two common systems that use cables, the PC/Expansion
Box combo and the TI99/4A both use driver/receiver cards *and* add wait states
when the external box is accessed.

Of course the sidecar *might* work just fine with a two foot ribbon cable
between it and the Amiga, but this setup is unlikely to pass FCC tests.  It is
one of those unpleasant facts of life that if a Commodore sells a product that
attaches to a specific device, it is the system, as configured, that must pass
FCC, not just the individual components.

>If the Amiga bus cannot drive an extra three inches of copper, then something
>must be seriously amiss at Commodore.
>
>Mike "deletion sort" Robinson                 USENET:  ucbvax!ernie!robinson

The 68000 processor drives the lines on the expansion connector, and sits about
one inch from the connector.  Most of it's loading and drive are devoted to
driving the on-board components.  The Zorro derived expansion boards are
required to promptly and efficiently buffer all relevant signals.  The prototype
Byte-by-Byte box I saw had these buffers on an adapter board that connected the
two boxes.
-----
Note:  I did not design either the A1000 or Sidecar, and can derive no great
enjoyment from defending the design issues implented.  What you do in the
privacy of your own home is between you, the FCC and your next-door neighbors
TV set.
-- 
George Robbins - now working with,	uucp: {ihnp4|seismo|caip}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@seismo.css.GOV
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)