Re: C64 Tower 
=============

Subject: Re: C64 Tower 
From: Matthew Hudson <mhudson@home.com> 
Date: Sun, 08 Mar 1998 21:05:17 -0600 

Nate Dannenberg wrote:
> 
> >
> > The 9VAC has nothing to do with timing.
> 
> Not exactly.  The 9VAC is used to drive the CIA's "TOD" clocks.  It uses
> the 60Hz pulse as a simple timing signal.
> 
> In PAL countries this is a 50HZ signal, which is why the CIA's have
> PAL/NTSC settings in them.
> 
> The 64 uses a 14.31818 MHz XTAL crystal (some 17MHz in PAL) as the timing
> base for everything, from which the VIC-II generates the "Dot"  clock (the
> pixel timer), the 3.58MHz (~4MHz PAL) color clock used for the color
> signal, and the 1.022 MHz system clock (0.98 Mhz in PAL).

I stand corrected (and verified it with the schematic). But in that
case a simple timer circuit would work just as well.

-Matt

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