Howdy!

I've got a quick update on SHARK TV-Out, with some good news and some
bad news.  First, the good news.  After a considerable amount of playing
around, I am able to get TV out, in color, without overscan, on SHARK
(in NTSC).  Contrary to my last memo on the topic, after the right bits
are turned on for TV-Out, the problem is, indeed, the color burst
subcarrier frequency (my brain had shut down earlier, and I'd forgotten
that this is just as important for S-Video as for composite output).  To
eliminate the horizontal overscan, I've upped the dot clock and set the
HSync appropriately, while vertical overscan is eliminated by simply
reducing the number of displayed lines (to ~450, from 480).

The bad news: so far, this has been done with gross and disgusting hacks
in the AV driver - fortunately, this is easy to change.  However, the
really bad news is that you may need to modify your SHARK.

Here's the deal.  As many of you know already, the Rev. 5 SHARKs were
being built just as IGS issued new layout considerations for the video
chip, and they have some video oscillator noise as a result (showing up
as pixel jitter on the display).  Some of your systems appear to work OK
as-is, while the majority exhibit some degree of jitter.  Unfortunately,
in the NTSC system, the color sub-carrier frequency is probably the most
critical oscillator frequency you will ever encounter (unless you work
at NBS!).  That's why it's specified as 3.579545MHz...  <Any> jitter
will show up as a dramatic color shift "dancing" around the screen.
Even on a SHARK which shows no pixel jitter, enabling the color output
shows lots of color jitter.  Ergo, for color TV-output, you will
probably need to install the Rev. 5 hardware mod, which is rather
non-trivial.

Regardless, I would like to thank the incredible folks at Firmworks, who
were kind enough to offer outstanding assistance on this problem, as
well as to IGS, who gave me access to more up-to-date documentation.

I'm out of town for a couple of days, but once I return, I'll start
working on AV again while I try to get a SHARK modified...

Cheers!
MarkF