Date   : Thu, 08 Jul 1993 11:23:35 +1200
From   : David Andrew Sainty <David.Sainty@...>
Subject: Colour Graphics 

On the hardware front, I've just found out something rather unusual! The
video character clock is synced with the system clock! I always thought
the 17.7345 MHz crystal was the video crystal, Does anyone know what
that's actually for? (Serial port?)

This puts a whole new perspective on the sync problem, just derive the
video clock from the 1MHz signal on the 1MHz bus!

Unfoortunately, the clock phase is not very nice. You only get one transition
per character in 80 column modes, and the transition is precisely on
the half character mark! Can't get much worse! :-) This appears to be the
case on Master and model B alike. A little problem....

Does anybody have the pinout for the tube connector? That no doubt will have
a faster clock line on it, but I don't have information on it.

There is an 8MHz clock on the cartridge socket on the master, that would solve
the problem for master users, but not model B'ers...