Hi Marko, > It's mainly a matter of clock speed. The 1541 runs at exactly 1 MHz (and > the 1581 and the 1571 in its fast mode run at exactly 2 MHz). But the C64 > runs either at 17734472/18 Hz (PAL) or 14318181/14 Hz (NTSC) or twice that OK, this is what I figured. > > How does this work out in terms of machine cycles? > > Well, the PAL C64 is slower than the drive, and the NTSC C64 is faster. > You have to remove delay from the drive code or add some delay to the C64 > code. Or use a protocol that is immune to the speed difference. In part I was wondering if this is a trial and error kind of thing, or if a more precise calculation may be applied, e.g. for every x cycles, add y cycles. My naive MHz calculation says that around 50 drive cycles is about 51 NTSC cycles (or 49 PAL cycles) -- in other words, that they stay more or less in sync for a pretty long time. Is it really a matter of a single cycle in just the right place? That being the case, surely it matters where the cycle adjustment takes place? Is there any rising/falling edge kind of thing that, say, halves the above calculation (1 cycle every 25 cycles, or some such)? Thanks! -Steve - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tcm.hut.fi.
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