>Unfortunately this kind of thing should be done step by step.

I think you are correct here. If it is going to be done with minimal chips,
it will need to be got together in stages.

>First you learn how to do the composite video sync, then you
>create the interlaced stable "odd black" - "even white" video
>signal, then, you draw a big rectangle in middle of screen,
>then, you learn how to calculate sine(x) and produce a big nice
>round circle, then you can go for characters drawing and character
>generators, then, after you have absolute knowledge about it,
>including plenty of available processing power in between vertical
>retrace, perhaps it would be time for color burst signals and such.

>VV46U3R

This sounds like a pretty good strategy to me. It would certainly help with
what I suggest below


>Tony Harris wrote:
>> Well, what I'd like to do is output information to a video handling
>> circuit. I've read about pong, and unfortunately, it is all black and
>> white, and it still seems that he said a lot of time was spent in
>> video processing - I need my chip available for other stuff.
>>
>> I'm thinking some sort of video circuit where it would know what mode
>> it was in (graphics or text) and I could fill a specified block of
>> ram with my data and it would spend the time drawing to the screen.
>>
>> I just don't know how to do this right.  :)

I think you are going to end up with multiple processors here, at least two.
One doing a pong like video generation, possibly locked to an external sync
source, and the other doing the pattern modification and whatever other
processing you want. I would also suggest moving to an 18f252 or 18f452 to
get the faster clock speed and 16 bit instruction set. Depending what other
processing you want, you may just get away with one of these.

As an extra on the 18f series, you can use a colour burst crystal as the
frequency source, and use the 4x PLL to have a reasonable speed processor
that will be reasonably closely synchronized to the TV scan rates :)

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