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From: augustss@chalmers.UUCP (Lennart Augustsson)
Newsgroups: net.arch
Subject: Re: DMA controller chips
Message-ID: <431@chalmers.UUCP>
Date: Wed, 15-Jan-86 22:37:53 EST
Article-I.D.: chalmers.431
Posted: Wed Jan 15 22:37:53 1986
Date-Received: Sat, 18-Jan-86 08:30:21 EST
References: <171@oasys.UUCP>
Reply-To: augustss@chalmers.UUCP (Lennart Augustsson)
Distribution: net
Organization: Dept. of CS, Chalmers, Sweden
Lines: 43

In article <171@oasys.UUCP> jcg@oasys.UUCP writes:
>
>As part of a design for a 80186-based controller, we've been looking at DMA
>controller chips.  We need four DMA channels (in addition to the two in the 
>'186) that may all be in operation concurrently.  The peripherals being 
>interfaced are 8-bit bus oriented, but the '186 has 16-bit wide RAM so we
>want the DMA to do word assembly/disassembly for us.  We have not been able
>to find ANY chip on the market which will do the job for us.

Being american perhaps you don't read european data sheets -:).
In any case, Siemens manufactures a DMA chip called SAB82258.  Some of the
features (from the spec):
	- 16 bit DMA Controller for ... 80186 ...
	- 4 independant channels
	- 16 Mbytes addressing range and byte count
	- Memory based communication with the CPU
	- "On-the-fly" Compare, Translate and Verify
	- Transfer rates up to 8 Mb/s
	- Automatic chaining of Command blocks
	- Automatic chaining of Data blocks
	- Multiplexor Mode Operation with 32 Subchannels
Naturally it handles byte assembly, and disassembly.
The channel programs are quite powerful (using selfmodifying channel programs
it is as powerful as an ordinary computer (at least in theory)).
This a new product, but it exists (I have programmed it).  The only thing
you won't like is the price, about 150$.
You can get information from
Siemens AG, Bereich Bauelemente, Produkt-Information
Balanstrasse 73,
D-8000 Muenchen 80
Bundesrepublik Deutschland (use Germany with Usnail)

Any resemblance of the opinions above to real opinions, living or dead,
is purely coincidential.
	Lennart Augustsson
UUCP:		{seismo,philabs,decvax}!mcvax!enea!chalmers!augustss
ARPA,CSnet:	augustss@chalmers.csnet
-- 
Any resemblance of the opinions above to real opinions, living or dead,
is purely coincidential.
	Lennart Augustsson
UUCP:		{seismo,philabs,decvax}!mcvax!enea!chalmers!augustss
ARPA,CSnet:	augustss@chalmers.csnet