Rickard Gunie wrote:
>
> I'm trying to generate a video signal using a PIC16F84 running at 12MHz,
> but i have some trouble with the frame-synchronization. (The picture is
> not stable) Could someone explain how the frame-sync works ?

Rickard,

You have not described enough about the signals that you are already
generating, but I am going to take a guess that you are not producing
the equilizing pulses that are needed before and after the vertical sync
pulse. These occur at 1/2 the horizontal period. The timing is too
difficult to explain in text. I suggest that you take a look at one of
the many books on the subject. If you have questions then, I would be
glad to help you.

Also, if you are not tied to using a PIC for this application, you might
consider a chip that Philips called "MTV". As I recall, it is an 8051
core with a video generator built in. Good Luck.