What's a WD2793A chip? - test-drb@ccmp.vtda.org

4 Feb 2000

The Feruson BIg Board ( of which I have a bunch) was single-density only,
for which clock extraction was dirt simple.  MFM requires a gentler hand.
It was, as you suggest, straight from the WD App Notes.

The Big Board-II used the 9216.

Back in those days, there was a big fight between the analog guys and the
digit-heads, and it didn't help a thing.  It got me paid for designs that
were never implemented on more than one occasion, even though my
meticulously designed and carefully stolen and tested, then improved digital
separators worked much faster and better than the analog ones.

Dick
-----Original Message-----
From: Al Kossow &lt;aek(a)spies.com&gt;
To: classiccmp(a)classiccmp.org &lt;classiccmp(a)classiccmp.org&gt;
Date: Friday, February 04, 2000 6:18 PM
Subject: Re: What's a WD2793A chip?

...
 "I've often thought that a PAL or small CPLD
would do the job.  Has anyone
written the appropriate state machine or equations?
"

From memory, didn't the Furgusson 'big board' use a digital data separator
that was a bipolar prom state machine? I know I've seen this same design in
several late 70's floppy controller boards (maybe it was even in the WDC
data sheets) 