Re: Questions about pal clocks

From: Jozsef Laszlo (
Date: 2001-11-22 15:54:02

> wheee..  if the TV doesn't just reject the colour information outright,
> there will be (18MHz-17.73MHz)*(~63 microseconds)=17 extra cycles
> of colour signal in each line.  This should make any solid colour into
> 17 rainbow bands, each about 30 pixels wide.  So the colours
> should be normal a bit less often than once every four chars :-)

Probably I'm worng, but the TVs have some tolerance for the scan line
timings. In theory one scan line must be 64us long, but if you calculate
the normal VIC timings, you'll see that is not this value in the C64:
DOTcloks*540 = one scan line,  (1/7.88Mhz)*540 = If I used
8Mhz for the DOT clock, it would be 67.5us.

(Correct me if I'm worng, please)

So The B/W picture sould appear in this case as well.
The color information is another question, that's
true. BTW, the VIC doesn't know about the different clocks, so it's gonna
work I guess. In the worst case I'd get a B/W picture.


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