Sync signal polarity

Sync signal polarity

Post by Peter Taylo » Fri, 07 Jan 2000 04:00:00



Can someone please explain what the + and - hsync and vsync
parameters in the mode lines do?  Am I going to damage my monitor by
experimenting with them?

I didn't see anything in the video timing how-to about how to figure out
if the polarity is right.  I don't see anything in my monitor's manual
about sync signal polarity.

Is it dangerous to play with the pulse widths as well?

--

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Sync signal polarity

Post by staffan.br.. » Sat, 08 Jan 2000 04:00:00




> Can someone please explain what the + and - hsync and vsync
> parameters in the mode lines do?  Am I going to damage my monitor by
> experimenting with them?

> I didn't see anything in the video timing how-to about how to figure
out
> if the polarity is right.  I don't see anything in my monitor's manual
> about sync signal polarity.

> Is it dangerous to play with the pulse widths as well?

> --


Hi!

This is from personal experience _way_ back, please take it for what it
is...

The +/- sign seems to tell the graphics card whether that very signal
should stay on a low potential most of the time so it can create a
positive flank for triggering (the + sign) or whether it should stay on
a high potential in order to create a negative flank. Not all cards
support this though. In my application I needed 5V for powering a
converter inbetween the graphics card and the monitor so I used -Hsync
and -Vsync to get enough supply voltage...

I wouldn't recommend playing too much with these parameters though since
it _can_ affect an old monitor. Try xvidtune in small increments to see
what you get.

Good luck!

                Staffan


Quote:

> Sent via Deja.com http://www.deja.com/
> Before you buy.

Sent via Deja.com http://www.deja.com/
Before you buy.

 
 
 

1. What is Sync. Polarity?

I have a Diamond Viper PCI 2Mb driving a Magic View 17H (I nearly fell
over when I saw specs. for this monitor when I was configuring Xfree86...
I thought I'd bought the only production model! But I digress...)

I want to play around with the Viper custom options to increase (in this
case, the 1280x1024/60Hz) to a less-flickerable 70+Hz. Under Dross, the
vprmode wants me to choose between Sync Polarities of

(H/V) +/+ -/+ =/- -/-

The manual with the monitor talks not at all about these... so what are
they and which ones do I use? And are they mentioned when configuring for
Xfree86 at all (once I've got this new motherboard completely working,
I'll be running SLackware Linux again)??

I've looked thru' the (somewhat mind-blowing) documentation on
configuring for X but nothing leaped out at me.

Thanks

Bill

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