That makes sense. And it goes with everything else I've read. Now, I did cheat and looked at the Mame Source for centipede (naughty naughty me!) It lists the XTL as 12.096. When you divide that by 8 for the 6502 you end up with 1.512. Also, there is a note that it should be 0.756 when accessing the playfield RAM.
On the Zarzon schematic the clock isn't clearly marked to say "Hey silly...here's your XTL.", but it does clearly show 11.289 which, if I were to cross-reference this with xtl.h would lead me to believe I was looking at the correct thing. I didn't see anything resembling 12.096 on the Centipede schematic. (Did I just miss it?) Is it possible to get this number from the schematic if the number isn't clearly written? Or is the only way to get it (other then finding it documented somewhere else) to measure it directly from the PCB?
ArcadeGamenut
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