Hello! Jozsef Laszlo wrote: > > Hi folks, > > I have two questions about the clock generation in the C64. > > 1. The source Quartz for the PAL system is 17.73442 Mhz. If I replace > this > quartz with an 18.000 MHz one, will it work? > Theoretically it should but I'm not sure in it. It probably will, but the video timing / color burst will be slightly off, thus the picture on the display will look strange / black & white. > 2. The VIC-II chip needs two input clocks: the color phase clock (this > is the > 17.7Mhz I mentioned above), and the DOT clock. The 8701 generates both > of > them, the color clock is the same as the source clock, and the dot clock > is > the source*2/4.5 rate, which is approx 7.88 Mhz. So more or less the > color and the > dot clocks are synchronized. My question is: do they absoultely need > this sync? They don't (Marko could probably tell you some interesting parameters about the first VIC-II equipped devices, with their separate 8Mhz dot clock source). But if they're not, the picture will look like 'grainy'. L. Message was sent through the cbm-hackers mailing list
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