VGA horizontal overscan

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JonB
Posts: 101
Joined: 08 Nov 2013 11:16

VGA horizontal overscan

Post by JonB » 20 Nov 2013 10:59

Hi

I noticed that the REMEMOrizer VGA output is overscanning (is that the right term) horizontally. The effect is loss of the bottom 4 lines of text. Neither of my monitors (which are both early VGA LCD) can auto correct it, and they don't have V-height controls (to compress the picture vertically, so that all scanlines are visible on the display). Is there a way of adjusting the video output on the REMEMOrizer card, either via software or hardware?

Regards

JonB

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AndyKey
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Joined: 12 Aug 2012 01:29
Location: Southampton, UK
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Re: VGA horizontal overscan

Post by AndyKey » 20 Nov 2013 21:47

I have seen and used REMEMOrizer on a variety of VGA monitors and have not seen this problem.
I did have to press the auto-adjust button once on one of them.

But I will concede that the VGA dot clock used by REMEMOrizer is 1.7% out from its correct value.
One user (Iain) reported that his TV (which supports VGA input) didn't like it, and he switched to using a VGA monitor.
Perhaps the TV in question is (legitimately) fussier than most.
This is mentioned on the Failures page of the REMEMOrizer website.
Perhaps your monitor(s) are also (legitimately) fussier than most.

Unfortunately, there aren't any tunable presets in REMEMOrizer for this.
The VGA signal is driven directly off of the fixed 49.152MHz clock on the GODIL, and works by counting clocks.
The number of clocks in the blanking intervals etc. are per VGA spec.

If you are able to find a monitor that is content with the signal (at least 20 folks have monitors that do), then great.
But if you're not, as I can't change the clock to exactly 50MHz, so unfortunately the only option would be to send it back.

Maybe folks could help by posting the makes/models of monitors they know to work with REMEMOrizer.
The monitors I tested your (well in fact, everyone's) REMEMOrizers on are AOC NW19 and NW19B (B=Black?) LCD monitors.

Sorry I can't be more helpful.
{{{ Andy

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