VGA display maximum resolution? \ VOGONS

VGA display maximum resolution?

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First post, by superfury

Posted on 2015-11-04, 07:49

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I know the display should be 640x480 pixels, but as far as I know the text modes are programmed for more than 640 pixels horizontally. Anyone knows what the actual maximum resolution of a IBM VGA CRT monitor is? I currently have my emulator set to a 800x600 pixels display maximum, but is this correct?

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Reply 1 of 4, by SarahWalker

Posted on 2015-11-04, 18:15

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720x480.

Reply 2 of 4, by Davros

Posted on 2015-11-04, 18:17

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https://en.wikipedia.org/wiki/Video_Graphics_ … _graphics_modes

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Reply 3 of 4, by superfury

Posted on 2015-11-05, 13:02

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So the maximum resolution of a VGA monitor is 720x480(NTSC?)? What happens when the CRTC is programmed for higher values than 720x480? Will part of it go over the edge of the screen(which won't be visible)? Or will it be resized to 720x480 in that case(looking at a LCD monitor)?

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Reply 4 of 4, by Scali

Posted on 2015-11-05, 13:29

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It's an analog system... You can stretch the specs somewhat, but at some point it will lose sync (original VGA monitors were not multisync like later SVGA monitors were, so they could only detect and sync to 70Hz 400-line modes (200-line modes were doubled by the VGA card to 400-line) and 60Hz 480-line modes).
So the image will start 'rolling'/'waving' over the screen etc.

800x600, 1024x768 and other modes were non-standard SVGA modes. How they worked depended on the video card and monitor that you used exactly. IBM didn't support these.
My first Paradise SVGA card displayed 1024x768 in a weird 43Hz interlaced mode on my Eizo Flexscan CRT.

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