[Coco] PICs and S-Video

Chris Hawks chawks at dls.net
Thu Feb 23 09:07:30 EST 2006

---Reply to mail from John Kowalski about [Coco] PICs and S-Video

> Maybe I'm overlooking something, but it seems that maybe an ordinary 556
> (dual timer) chip could do the trick.  It wouldn't delay the HSYNC per-se,
> but I figure it could be used to generate a new HSYNC signal using the
> original HSYNC for reference.

> Possibly something along the lines of:
> -Timer 1 being set to the delay between the original HSYNC and the new HSYNC.
> -Timer 2 being set to the pulse width of the new HSYNC.
> -The original HSYNC would trigger timer 1 and reset timer 2.
> -The output of timer 1 would be your new HSYNC and also trigger timer 2.
> -The output of timer 2 would reset timer 1.

    Yeah, that's how it started. But, the 555(6) output is high when the
trigger is low (and HSYNC from the Coco3 is a high pulse), so I'll have to
invert HSYNC (another chip!) before it's fed to the timer 1. I should
be able to de-couple the connection from timer 1 to timer 2 with an RC

---End reply

Christopher R. Hawks
Hey! It compiles! Ship It!

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