sicklittlemonkey wrote:
Actually, once you achieve lock, you never look at VBL or the vapor lock bytes again. You just count cycles perfectly, and the processor stays in exact sync with the video generator.How many cycles? NTSC or PAL? ;-) Cheers, Nick.
That, too, can be determined by timing VBL or vapor lock bytes! ;-) Of course, a program that was attempting to run within these timing constraints would have to be written for the tightest constraint, then precisely padded if the longer case is found. I don't know whether the few programs that used this technique actually adapted to PAL--perhaps our PAL pals know. ;-) -michael Music synthesis for 8-bit Apple II's! Home page: http://members.aol.com/MJMahon/ "The wastebasket is our most important design tool--and it is seriously underused."