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I have a guide that tells me that for interfacing 640x480 screen you need 800 pixels in a row and 521 lines along with all of that front and back porch stuff I wanna know how do they determine that number? If i have a screen of different resolution how do i determine the pixels and lines? also the non displayable area i.e porches and retrace time , how are they determined

Ishmeet Bindra
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  • I would try and find an older graphic processor chip datasheet that still lists some of the low level parameters to find out what was used in the old standard display modes. As for calculating I suspect that they were pragmatic numbers decided on by the monitor industry for ease of scanning electronics and by the video card people for minumum wasted retrace times as long as the clock cycles were usually 'nice' multiples of powers of two I suppose. – KalleMP Jul 31 '16 at 06:27
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    @KalleMP [This page](http://martin.hinner.info/vga/timing.html) has tables of parameters for various resolutions, in four tables with over a hundred different entries total. – tcrosley Jul 31 '16 at 06:42
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    If you use VESA DDC, you can simply ask the monitor for this information. Or there will be a table in the VESA standards. – pjc50 Jul 31 '16 at 07:49
  • @tcrosley how do you determine that 800 clk pulses are req for 640 pixels? – Ishmeet Bindra Jul 31 '16 at 08:55
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    It's not something that's calculated, it's something that's specified. – pjc50 Jul 31 '16 at 10:57

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