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From: garyf@wiis.wang.com (Gary Field)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: SCSI protocol and chips...
Message-ID: <1990Aug2.173530.1257@wiis.wang.com>
Date: 2 Aug 90 17:35:30 GMT
References: <428644@neabbs.UUCP>
Organization: Wang Laboratories, Inc
Lines: 43

joost@neabbs.UUCP (JOOST BOERHOUT) writes:


>     Hi netters,
>     I want to design my own SCSI interface (hardware and software) for
>     the Amiga market.  Although I have  a some  information about SCSI
>     I'd like to have the full  documentation found  in the ANSI X3T9.2
>     specs. Does anyone know how I can obtain these ?
>     Futhermore, I took  a  serious  look at the Am5380 SCSI controller
>     from   Advanced  Micro  Devices.  Does  SCSI  really  have  to  be
>     implemented that ugly ?? I bet someone knows a better chip, please
>     let me know.
>     - joost -

I don't have the info handy but I know where you can find out.
Call the Common Access Method / SCSI BBS at (316) 636-8700. There is
a message on there that tells how to obtain paper copies of the various
SCSI specs.
As for the selection of a SCSI controller I'd probably choose the NCR 53C94.
Performance is quite high and seems pretty bug free. Whatever you do, do
NOT use a WD 33C93! That chip seems great until you start handling all
the error conditions. The 5380 is strictly a low cost device that is OK
for low performance devices, but will not do a nice winchester justice. It
requires too much software intervention for handling each bus phase. 
Now that I've told you all this, I must ask, do you really want to design
yet another SCSI controller? There must be > 10 on the market already!
If you do, do me a favor and adhere to the new ANSI CAM/SIM spec for
the driver interface, this will allow others (like me) to add their
own drivers for oddball devices without having to rewrite everything
from scratch.

GOOD LUCK!

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