Re: petSD project page

From: Rhialto <>
Date: Mon, 20 Jun 2011 16:27:53 +0200
Message-ID: <>
On Mon 20 Jun 2011 at 11:56:41 +0200, Ingo Korb wrote:
> Jim Brain <> writes:
> > Scanning both busses might be an issue, but maybe not insurmountable.
> The easiest way would be to wait for an ATN signal from either bus at
> startup, then servicing only that bus until the AVR is reset. This
> scheme might switch to the wrong port if there are other devices
> connected on both ports and not all of them are powered on.

I wasn't even thinking of having both ports connected at the same time.
That might people lead to expect that it worked like a protocol
converter! (Not a usless thing, of course, but that wouldn't work in the
current firmware, I expect).

I remember that at school, we had at some point at least 4 PETs
connected to a single 4040 disk drive and a 4023(?) printer using metres
long custom IEEE cabling that was chained from computer to computer and
finally to the disk drive and printer. (Maybe they were somewhere in the
middle, I don't remember; and possibly it was a star topology instead of
a chain (at least it would have been like that as an initial version)). 
Worked fine - as long as no two computers would try to use the bus at
the same time.

___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you 
\X/ rhialto/at/    -- can't be childish sometimes. -The 4th Doctor

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Received on 2011-06-20 15:00:17

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