Re: [stella] NTSC/PAL detection

Subject: Re: [stella] NTSC/PAL detection
From: Jan Paul Schmidt <jps@xxxxxxxxxxxxx>
Date: 06 Aug 2001 12:58:53 +0200
Am 05 Aug 2001 18:01:32 +0200 schrieb Manuel Polik:
> Jan Paul Schmidt schrieb:
> > Sorry for this, but I'm back from vacation, where I was thinking about
> > this. I saw, after going through the mails of the last weeks, that there
> > was a discussion about this topic. I'm currently not very familar with
> > the timers, but what is the reason, why something like setting the
> > timer, waiting for two vertical blanks and looking where the timers is,
> > does not work to detect a NTSC or PAL system?
> That's because the vertical blank is just as long as you make it,
> totally indepent from the TV system the console is hooked to.

After reading the Stella manual again, I catched my error. You can't
wait for a new frame, but you signal when a new frame starts. OK, big
difference here! Next question :o) NTSC needs 40 scan lines for VBLANK
and PAL needs 48 scan lines for VBLANK. What happens, if you do more
than 40 scan lines on NTSC, say 48? Does this work? Ignoring color
differences on NTSC and PAL, is it possible to write a syncronisation
routine with this for NTSC and PAL? Yes, your are loosing scan lines on
NTSC etc. But is it?


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