Video sync is a solvable problem. Either take the signal where it is
available (IIe slot 7, etc.) or write a program that will allow the VGA
card/software to sync.
True. Maybe even write a signature to the beginning of the video memory
and sync to it. Once in sync it should stay in sync till a reset, so the
signature doesn't need to stay there longer than a few milliseconds.
-Alex.
I would prefer a method that doesn't require interfering with the
operation of the Apple.
I also don't understand why it would necessarily stay in sync. Is it
safe to assume that the Apple's crystal and the Carte Blanche crystal
are so close to the same frequency that they would not drift out of sync
in a noticeable amount of time?
You would not want to use the CB's on-board clock. Instead, you would
want
to utilize the FPGA's DCM (digital clock manager, usable as a
frequency
multiplier) to derive your operating clock based on the A2's own 14M.
In this case, you would indeed stay in sync.