Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!decwrl!sgi!cdp!gperkins
From: gperkins@cdp.UUCP
Newsgroups: comp.sys.ibm.pc.misc
Subject: PC/AT DMA CHANNELS AND MEM BUFFRS
Message-ID: <140700036@cdp>
Date: 20 Feb 91 01:46:00 GMT
Lines: 17
Nf-ID: #N:cdp:140700036:000:802
Nf-From: cdp.UUCP!gperkins    Feb 19 17:46:00 1991


        Help! I am working on a project that interfaces a PC via a
DMA channel.  The DMA channel (1 or 3) sends high speed data over to
the PC. I know how to set up and use the PC's DMA chip but
I can't figure out where to start the DMA capture data in the
PC's memory.
        What I need is to find some (several HUNDRED K, or whatever I
can get) memory "past" the top of my PC program for a capture
buffer.  I can't seem to find information on something this specific.
Do I need to declare some whopper data structure ahead of time, or
use a malloc()-type method?  I need to stay  within the standard 640K
PC and AT memory arrangement.   If anyone knows of some references,
or examples from projects in books or magazines, PLEASE email me!  
Thanks very much!

Gordy Perkins
Mpls,MN