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From: kushmer@bnlux0.bnl.gov (christopher kushmerick)
Newsgroups: comp.os.msdos.programmer
Subject: Can someone explain this to me
Message-ID: <2493@bnlux0.bnl.gov>
Date: 7 Feb 91 22:27:57 GMT
Organization: Brookhaven National Lab
Lines: 27

I have a data trranslation card, dt2851, a frame grabber with 512 K byte
buffers on board. The manual says that I can select the portion of address
space that this will occupy. The factory configured base address is
$A00000 (Thats right, 5 zeros). This ram is probably dual ported because the
manual says that I can read/write it at any time ie with out worrying about
conflicts with the frame grabber hardware.


Now the questions:

How many address lines are there on the AT bus? Does the 80286 not have
20 address lines? What is conffusing me is how I could ever read/write
to addresses in the range of $A00000. In theory this would be segment
$A0000. But turbo pascal 5.0 and turbo debugger both seem to only accept
address in the range of roughly  $FFF0 (For the segment).


Any infomation on what I am worrying about is appreciated.


Is there still a ibm.pc.hardware group?


-- 
Chris Kushmerick                                 kciremhsuK sirhC
kushmer@bnlux0.bnl.gov    <===Try this one first
kushmerick@pofvax.sunysb.edu