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From: A0061@DK0RRZK0.BITNET
Newsgroups: mod.computers.vax
Subject: DRV11 on the uVAXII
Message-ID: <8612051320.AA03052@ucbvax.Berkeley.EDU>
Date: Fri, 5-Dec-86 09:08:02 EST
Article-I.D.: ucbvax.8612051320.AA03052
Posted: Fri Dec  5 09:08:02 1986
Date-Received: Fri, 5-Dec-86 20:54:19 EST
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Organization: The ARPA Internet
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Approved: info-vax@sri-kl.arpa

Yesterday I worked on some data acquisition program for a uVAXII. It
uses a DRV11 16 Bit paralel interface to poll for the status of some
digital input lines. The same type of program on a PDP 11/73 or so
works fine, but on the uVAX I often read some trash instead of the
correct data word out of the DRV11 (using $CRMPSC with page frame number
mapping). Note that no interrupts are involved, just normal device-
register to memory operations. A work around was found by reading the
register twice and if good compare taking the data as valid.

How come ? Any ideas ?

Claus Kalle, Regional Computing Center, Cologne University, West Germany