Re: confused, seems to be my normal state
On Wednesday 18 September 2019 16:09:48 Joe wrote:
> On Wed, 18 Sep 2019 10:20:22 -0500
>
> John Hasler <jhasler@newsguy.com> wrote:
> > Your scope could show you eye patterns but that's probably of little
> > use. You need to look at all three data channels and the clock
> > (these are differential so you need eight inputs) and trigger on
> > patterns. otherwise all you will learn is that the interface is
> > clocking.
>
> I suspect that if all eight lines are waggling, that's good enough.
>
> By the way, I have a 40MHz scope whose response extends far enough to
> show a thickening of the trace on 1.5Gb/s signals, which is good
> enough for presence/absence.
>
> What would be a real pain is actually accessing HDMI signals while the
> thing is running. It's no good just looking into a connector, it needs
> to see something hanging on the end before it will power up and
> activate.
IOW, disconnecting and looking into the connector with a scope probe is a
waste of time. HDMI is post my time in the broadcast business by 15
years, so I know little about it from my former $dayjob. I had the
obligatory turkey dinner and collected the Rolex in the middle of 2002,
haveing sat in that chair, when I had time to sit, since Oct 1984 and
monitors were just gettiing smart enough to tell the drivers what they
needed, so I had suspected as much.
Thank you Joe.
Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>
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