
Due to (very) popular request, here are a bunch of PAL/NTSC compatible
modelines.

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These are actually quite useless, because they will produce a NON-interlaced
output (VGA textmodes don't seem to work interlaced, at least on the card I
tried).

Most TVs and VCRs will work with these modes however, albeit not optimally.

You will need an external device to convert the RGB/H/V output of your VGA
card into something a TV or VCR can grok.

PLEASE DO NOT ASK ME HOW TO DO THIS, You're on your own. I will NOT reply
to a zillion requests to present a method to make this work. These
modelines were added because many people

                                    -----

If interlacing were to work in text mode, these modes should be possible:

 "PAL_80x36"   13.711   640 658 716 780  576 578 584 625  font 9x16 Interlace -Hsync +Vsync

 "NTSC_80x30"  13.711   640 658 716 780  480 482 488 525  font 9x16 Interlace -Hsync +Vsync
 
Since at this moment, interlacing is not supported in textmode, the following
will have to do:

 "PAL_80x24"   13.711   640 658 716 780  288 289 292 313  font 9x12 -Hsync +Vsync

 "NTSC_80x20"  13.711   640 658 716 780  240 241 244 263  font 9x12 -Hsync +Vsync
 

You can derive a ton of modes from these. Basically, all that counts is a
horizontal sync rate of 15625 Hz, and a vertical rate of 50 Hz (PAL or 60 Hz
(NTSC). 

                                    -----


But that isn't all...

Of course, you can't display this on a standard VGA monitor (the Hsync rate
is 15.625 kHz, and the Vsync rate is 50 Hz interlaced -- quite horrible on a
non-long-persistence picture tube used in a computer display).

So you need some output you can connect to a TV (or VCR).

Most European TVs have a SCART connector, which allows you to input RGB
analog video to the TV. You need a composite sync, however, and a VGA card
outputs separate H- and Vsyncs. WIth the modeline above, adding a XOR gate
(e.g. 74LS86) that exclusive-ORs the (negative) HSYNC and the (positive)
VSYNC together produces the required negative composite sync.


That should get you a picture on the TV.

But to record it on a VCR is a whole different ballgame.

VCRs (at least consumer recorders) don't have RGB inputs: they require
"composite" video (R, G, B, and sync put together in one signal (for CVBS)
or 2 signals (for "SVHS", aka "Y/C")).

To that end, there are a number of solutions, but all of them require a bit
of electronics.

What you basically need to do is first convert R, G, and B to Y, U and V
signals, then modulate U and V with the color carrier frequency, and add
those, Y and sync together on one output.

There are a number of solutions to this, but the Analog Devices AD722 is
probably the easiest solution (1 small IC, one crystal and a few C's).
Analog Devices even has a demo board for this chip that comes with a floppy
that will reprogram your VGA card to output video (but the demo program
doesn't put the card in interlaced mode, which gives a bit of a funny
display). There's more information on this chip on http://www.analog.com.



PLEASE do NOT ask me for schematics, hardware, demo boards or anything else
that you need to get this going. You're on your own. I can and will NOT
reply to a zillion requests to present a method to make this work.


