Quote:
Originally Posted by Toni Wilen
I timed how long it takes from vblank to line 1. It takes much longer than any other normal line (about ~25x). I guess it was not properly documented long time ago and someone thought it means first visible line and someone else that it means second "real" line.
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I'm not sure if I fully understand the "from vblank to line 1". Do you mean from
end of vblank to line 1 or from
start of vblank to line 1?
Normally the vblank takes much longer than 1 scanline, including front and back porch signal it would take about 25-26 lines for a normal PAL signal. This seems like close to the ~25x longer you mention. So I guess what you're actually measuring is the time from
start of field blanking to the first visible line? See this page halfway down
http://martin.hinner.info/vga/pal.html. The letter "j" in the Field Synchronization of PAL System represents the Field-blanking interval, and takes about 25 lines. From what I understand these synchronization blanking times are valid for LED monitors also, because of compatibility reasons. But maybe we're talking about two completely different things here?
Page 39 (png_039) of the Agnus specification sheet shows a comparable picture with regards to the blanking time btw (they're still a bit different though..). It's taking about 26 lines for the whole field blanking.