RE: 6510 CPU extensions

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Hallo John,

> Now my memory fails me... the 6502 outputs the clock on a 
> couple of pins, to feed to other devices that might need
> it.  Does the 6510  do the same?

An addition to Gideons answer: the input of a 6502 is called PHI0 (PHI
zero). The 6502 outputs TWO clock signals: PHI1, the inverse of PHI0, and
PHI2, a delayed version of PHI0. There is a delay between the flanks of PHI0
and PHI1. Never measured it exactly but I thougt it was about 12 ns.

Some computers don't need PHI1. The first model of the VIC-20, the one with
only 2114-SRAMs, doesn't need it. Its successor, the one with 2K*8 SRAMs,
does.
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