[Coco] VDG weirdness

[Phill Harvey-Smith]

On 19/10/2015 22:40, John W. Linville wrote:
> That's pretty cool, Phill!  After seeing the old Atom color boards
> I had thought to do a similar project at some point.
>
> Do you have any plans to market such a board?

Well I'm thinking about it but got a couple of other projects on the go 
at the mo. And it's kinda still in development because of the PAL / NTSC 
thing.

Basically I'm maybe going to implement the PAL additional line logic in 
the CPLD so that it just relies on the VDG clock output by the SAM (and 
disconnects the 6847's VDG clock from any circuitry on the motherboard).

This should make it independent of the various different models of both 
the CoCo and Dragon motherboards, and as a side effect should enable a 
machine to run at either frame rate (if I get it right).

Cheers.

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.