Path: utzoo!mnetor!uunet!husc6!cfa!ward
From: ward@cfa.harvard.EDU (Steve Ward)
Newsgroups: comp.os.vms
Subject: Re: Need help with VAX/VMS DMA data transfers
Message-ID: <924@cfa.cfa.harvard.EDU>
Date: 19 Mar 88 17:33:34 GMT
References: <713@moogvax.UUCP>
Distribution: na
Organization: Harvard-Smithsonian Ctr. for Astrophysics
Lines: 35
Keywords: DMA, data acquisition, device driver
Summary: DEC has DMA data acquisition software

In article <713@moogvax.UUCP>, terry@moogvax.UUCP (Terry Westley) writes:
> H E L P  ! ! !
> 
> I am using a MicroVAX II with VMS for a real-time application in which
> I need to perform some analog data acquisition in which other
> processing is so heavy that I don't want to use a device driver.
> I'd like to simply access the registers of my board (a Data Translation
> 3362) and DMA the acquired data into VAX memory.
> 
> I have been able to successfully perform data acquisition with a
> programmed I/O technique, but I have discovered that DMA transfers
> require a lot of knowledge about map registers and buffered data paths
> that I do not possess.
> 
> Does anyone have a snippet of code in any language that shows how I can
> set up and perform DMA transfers from any board.  High-level language
> (C specifically) would be perferred, but "beggars can't be choosers."
> I have a DEC manual on how to write device drivers, but am not able to
> make heads or tails of it.

If you might consider buying some software, DEC now sells a piece of
software called VAXlab or VAXstar or somesuch that supplies a full
library of drivers for all the standard Q-bus data acquisition and
parallel interface cards.  Also included is a menu interface that allows
configuration via a question-answer dialog.   Further, the package
includes display management and data analysis with plotting, data
capture and other features.

Of course, if you can't buy it then this will be of no help.  I believe
the approximate cost for a VAXstation II is around $2k, but you will
have to check with your salesman for the cost on your particular VAX.

Unfortunately I don't have any example code under VMS.

.