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From: csbrod@medusa.informatik.uni-erlangen.de (Claus Brod )
Newsgroups: comp.sys.atari.st
Subject: Re: TT RAM
Message-ID: <3118@medusa.informatik.uni-erlangen.de>
Date: 19 Sep 90 11:32:02 GMT
References: <3107@medusa.informatik.uni-erlangen.de> <2304@atari.UUCP>
Organization: CSD, University of Erlangen, W-Germany
Lines: 22


apratt@atari.UUCP (Allan Pratt) writes:

>The ACSI DMA chip can access memory only in the low 24 bits of the
>address space, so that's your answer: you check the high byte of the
>transfer address. If it's zero, you can use ACSI directly.  If it's
>not, you must use the FRB.  You never examine any part of the address
>other than the high byte, and you only test that against zero. 

Ah, that's it. Tnx!

>VME memory is not accessible to SCSI, and you should use the buffer
>pointed to by the _FRB cookie.

Hum, hum, and how do we detect that some RAM is a) VME RAM and b) 16
bits wide? Did I miss something here?

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Claus Brod, Am Felsenkeller 2,			Things. Take. Time.
D-8772 Marktheidenfeld, West Germany		(Piet Hein)
csbrod@medusa.informatik.uni-erlangen.de
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