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From: terry@cs.weber.edu (A Wizard of Earth C)
Subject: Re: Question on Diamond Clock Synthesizer
Message-ID: <1992Oct15.031343.16152@fcom.cc.utah.edu>
Sender: news@fcom.cc.utah.edu
Organization: University of Utah Computer Center
References: <1992Oct13.175214.19534@fcom.cc.utah.edu> <1bfp2oINNn4a@maverick.ksu.ksu.edu> <1992Oct14.033731.28397@fcom.cc.utah.edu> <1992Oct14.144110.8875@osf.org>
Date: Thu, 15 Oct 92 03:13:43 GMT
Lines: 56
In article <1992Oct14.144110.8875@osf.org>, kenny@osf.org (Kenneth Crudup) writes:
|> In article <1992Oct14.033731.28397@fcom.cc.utah.edu>
|> terry@icarus.weber.edu writes:
|> >All this is now totally beside the point: I now have it on good authority
|> >that the original code posting was either accidently or maliciously "doctored"
|> >to set the clock at the highest possible value --
|>
|> >..."If someone compiles that code thinking that it will set up the clocks
|> >for him, his monitor will likely go 'pop'".
|>
|> Yeah. Right. Who is your "good authority"? Someone from Diamond Legal?
Not!
The clock frequence it selects is (I think -- can't quite remember) 120. The
harmonics on this could probably cook a monitor with either older electronics
or a PLL that tries too hard to match them, and rapidly switches frequencies.
It is fixable with a code change, but I don't want to get into supporting
code that supposedly discloses a trade secret.
|> The old IBM monochrome monitors had a non-recurring-sweep horizontal (==
|> high voltage) output section. You could feed that monitor any H and
|> was outside a certain range, the HV output transistor would draw too much
|> current through the flyback transformer, and the only damage was a 10-
|> cent fuse, (which IBM in its infinite wisdom (NOT!!) decided to solder in
|> so that the non-wireheads had to take it in for service).
The monitor I cooked cooked better than that -- I had to replace a trnsistor,
the flyback, and one polar (probably should have been bipolar) capacitor.
Still less than half what Samsung would have asked to repair it.
|> Any VGA monitor (== any monitor you're going to plug into that SS24X) has
|> a real, live horizontal output section with lockable free-running oscillator.
|> If you feed that monitor a signal out of range, the PLL (or whatever is
|> applicable) will say "screw you", do the best it can, but not fall outside
|> of its designed range. No "pop".
|>
|> Please don't spread propaganda.
All I said was that I wouldn't use the code as a result. If the frequency
values were deliberate, then there's no way to tell if the code actually
does everything necessary to set the clocks the right way, other than our
belief in "Batman"'s good faith, which is now suspect.
Terry Lambert
terry@icarus.weber.edu
terry_lambert@novell.com
---
Any opinions in this posting are my own and not those of my present
or previous employers.
--
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