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From: rhyde@ucrmath.ucr.edu (randy hyde)
Newsgroups: comp.sys.nsc.32k
Subject: Re:  PC532 Expansion & other questions
Message-ID: <10179@ucrmath.ucr.edu>
Date: 28 Nov 90 18:03:33 GMT
References: <9011280218.AA24024@Shiva.COM>
Sender: news@ucrmath.ucr.edu
Organization: University of California, Riverside
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My board arrived.  Currently I'm pouring over the schematics before turning
on the soldering iron.  I've got a couple of questions someone might be able
to help me with.

1) I note that the DUARTs live at ports 2800020, ...40, ...60, etc.  Yet the
   address lines going into the 74138 imply that they should be at base
   addresses ...10, ...20, ...30, etc.  Is the documentation correct?  If so,
   is this an artifact of the decoding for the ICU?

2) I'm interested in a little off-board expansion without going through the
   SCSI bus (I'm not ready to tackle the design of a smart SCSI controller).
   I was thinking of popping off one of the DUARTs, running a couple of addit-
   ional address lines (and unused decoding lines from the '138)
   over to the socket and building a daughterboard to plug into
   the DUART socket.  I'd like to put a couple of parallel ports
   (perhaps a 6522 or 8255), an 8530 (I want to build an Appletalk
   interface), and some other devices.  Any problems anyone can warn
   me about?

3) Along the lines of question 2, I'd like some additional interrupts.
   can I cascade another ICU using the daughterboard technique des-
   cribed above?

4) Where do I get documentation for the monitor program?

5) Are the source listings available for the monitor?  I'd like
   to see some code for initializing all the chips.

Thanks,  Randy Hyde
.