Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!oakhill!motaus!skipper
From: skipper@motaus.sps.mot.com (Skipper Smith)
Newsgroups: comp.arch
Subject: Re: Coprocessors - Business?
Message-ID: <1991Mar28.225551.4925@motaus.sps.mot.com>
Date: 28 Mar 91 22:55:51 GMT
References: <2892@megatek.megatek.uucp> <3299@crdos1.crd.ge.COM> <1991Mar28.142109.1148@hobbit.gandalf.ca>
Distribution: na
Organization: Motorola Semiconductor, Austin, Texas
Lines: 24

In article <1991Mar28.142109.1148@hobbit.gandalf.ca> dcarr@hobbit.gandalf.ca (Dave Carr) writes:
>In <3299@crdos1.crd.ge.COM> davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr) writes:
>>The discussion of kernel CPU vs smart controller could become more
>>interesting if someone made a general i/o processor as a coprocessor.
>>The best of both sides of the discussion.
>
>Was Intel before its time.  The 8089 ?? seems to have died quickly.

Well, it doesn't technically qualify as a coprocessor (the origin of this 
thread), but the Motorola 68020 has been fully documented on how to use it as
an 8 channel DMA controller.  Since all of the code to run all eight channels
fit into the 256 byte onboard instruction cache, it is almost like having it
microcoded into the machine.  The unfortunate part is the amount of glue logic.
It takes quite a bit to turn the '020 into "just" an I/O processor.  However,
the design is easily upgradable to the 68EC030 (68030 w/o MMU) which would gain
you the additional speed of burst or the 68EC040 (68040 without a lot of stuff
:-) which would give you bursts on writes as well as another 2792 bytes of
instruction cache to do other things (like be an interrupt processor, too).
Just ask for DC003 at your friendly neighborhood Motorola sales office.

-- 
Skipper Smith                             | skipper@motaus.sps.mot.com
Motorola Technical Training               | 8945 Guilford Rd  Ste 145  
All opinions are my own, not my employers | Columbia, MD 21046