roberts@nbs-vms.ARPA@caip.RUTGERS.EDU (02/01/86)
From: "ROBERTS, JOHN" <roberts@nbs-vms.ARPA>
How does the Amiga in non-interlaced mode persuade the monitor to
exactly retrace the first field in the second field of the frame?
John Roberts
roberts@nbs-vms.ARPA
------hull@hao.UUCP (Howard Hull) (02/03/86)
> How does the Amiga in non-interlaced mode persuade the monitor to > exactly retrace the first field in the second field of the frame? > John Roberts > roberts@nbs-vms.ARPA I seem to have no possibility of getting mail through to John by the "r" command. The mailer can't find the site, and sends the mail back along the news path through topaz and caip. The caip site *always* rejects it (The deamon there hates return mail). So I guess I'll just post the reply here... The Amiga doesn't have to convince the monitor to overlay the second field of lines on top the the first. The monitor *wants* to do that just naturally. What is more likely a task for the Amiga is to get the monitor to interlace properly. To do that, the Amiga must generate "equalizing pulses" at twice the normal line rate during the vertical sync interval, and then momentarily invert one of the vertical sync horizontal pulses to get the monitor to sync half a line later than normal. At the bottom of that frame, it then must repeat this stunt, but half a line earlier. [If yet unproven concepts are outlawed in the range of discussion... ...Then only the deranged will discuss yet unproven concepts] {ucbvax!hplabs | allegra!nbires | harpo!seismo } !hao!hull Howard Hull