Hi Nicolas, > I wonder what is different in the C64: Many other Commodores use the same > clock sharing (like the VIC-20, probably some PETs/CBM-IIs, the dual drives > and some printers. The only unique thing about the C64 is the ability to > actually stop the CPU completely. don't know exactly of this, this is only from my memory of that article. Anyway, I'm surprised that the other CBMs (pre-C64, so to speak) support the same clock sharing. (I don't know anything about them.) I thought an "improvement" of the 6510 over the 6502 was that it could tristate its outputs. Did the VIC-20 (for example) have specific tri-state buffers which did that? Then, possibly, this external circuit imposed another timing than in the 6510 approach? Another possibility would be that this "real behaviour" of the ICs is not was is stated in the "data sheets" (assuming my memory from that article is right, and that article was right). For example, the sheet would tell that there is a setup time for the lines before PHI2, but in fact, it is not really needed. Just a thought, Spiro. - This message was sent through the cbm-hackers mailing list. To unsubscribe: echo unsubscribe | mail cbm-hackers-request@dot.tml.hut.fi.
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