Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!wuarchive!decwrl!ucbvax!HEITUE5.BITNET!WWDONIC
From: WWDONIC@HEITUE5.BITNET
Newsgroups: comp.sys.apollo
Subject: DMA on DN4000 AT-bus
Message-ID: <9001031702.AA06593@umix.cc.umich.edu>
Date: 3 Jan 90 13:01:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 29

We have a measurement system that produces a continuous stream
of 16-bit parallel data (about 20k words per second).  Each valid
word is accompanied by a strobe.

This system has to be interfaced to an Apollo DN4000 in such a way
that all data generated during a fixed period of, say, 10 seconds
can be stored on a disk file.  The idea is to use an AT-bus parallel
IO card and the DN4000 DMA controller for this purpose.  The DN4000
is running OS version 9.6.1 and GPIO has been installed.

Before starting this project, I need answers to these questions:

1. Has anyone done a similar thing before?  The Apollo people here
can only say "it should be possible", and don't give any specific
examples.

2. The example provided with GPIO (floppy driver) does not deal with
a continuous stream of data; the floppy controller stops sending data
after each sector (512 bytes).  Is it possible to read in a much larger
amount of data (400k) without losing anything ?

3. Do I have to upgrade the OS ?

Please reply directly to me, I'll summarize for the list.

Ton van den Bogert
Dept. of Veterinary Anatomy
University of Utrecht, The Netherlands.
E-mail: WWDONIC@HEITUE5.BITNET