Connecting VGA-cards to TV? 16
stein asks:
"Is it possible to connect a gfx card without
a special TV-out to a TV? I was thinking of making a
VGA-to-Scart cable and program the gfx hardware to TV
compatible frequencies. (Scart is a standard I/O connector
found on most modern TV-sets, has audio/CVBS/RGB
inputs/outputs). Programming the HW should be easy using
XFree86 under some UNIX system. And off course
I wan't to do it on a PC. I have a Riva TNT board.
So has anyone done this?"
X on TV -- found one circuit (Score:1)
this discussion prodded me to re-find a good discussion of vga-->tv converters. See
http://www.sput.webster.nl/hardware/tv-x.html
again, it's to the european SCART RGB input, but i recall (probably incorrectly) that the signal levels therein are pretty well universal, it's just a matter of digging inside your tv for the right place to inject them -- the rgb+sync typically originate on a generic tuner/decoder board + run to a tube-specific deflection board.
but you might have to go back a few years in teev technology to the sort which actually have separate boards -- look for marked r/g/b/hsync/vsync test points
DANGER DANGER DANGER (Score:1)
If you plan to open up your TV set to add inputs and outputs that the manufacturer didn't include, be aware that many, many sets ARE NOT ISOLATED FROM THE POWER LINE! and even if you don't kill yourself you'll probably fry something expensive (in/on your computer), maybe start a fire, unfun stuff like that. Get an old VCR, input to its aux inputs, use it to output channel 2 or 3 or 4 to the RF input of the set.
floating text? (Score:1)
Dunno how, but it must be possible... (Score:1)
According to all the info I've seen, the new Matrox G400 series has two VGA out ports, but it can output the secondary one to a TV, so it must come with some kind of adapter. You may want to either:
Either way, I'm planning on getting a G400 in a week or so; I'll see how it works and post the results in here. (Assuming I can find one in the next week.)
easy ... not really (Score:1)
your tv
2) connect rgb,grounds,vertical & horizontal sync
3) calculate "video modes", hint: 15.6 KHz and
50/60 (pal/ntsc) Hz
4) if you kill any hardware, its not *my* fault it's yours!
(i'm not liable for anything !!!!)
vga pinouts:
Female HDD15 VGA Connector
Pin 1: Red Video *
Pin 2: Green Video *
Pin 3: Blue Video *
Pin 4: Ground
Pin 5: Unused
Pin 6: Red Ground *
Pin 7: Green Ground *
Pin 8: Blue Ground *
Pin 9: Unused
Pin 10: Ground
Pin 11: Ground
Pin 12: Unused
Pin 13: Vertical Sync *
Pin 14: Horizontal Sync *
Pin 15: Unused
use shield for general ground.
DOS on a TV box (Score:1)
I don't know if this would apply to you, since this graphics card already converts the signal to the type my TV expects, but anyway:
I wrote a simple DOS TSR which hooks the video interrupt (0x10), and in case a text mode (0x3) or 320x200x256 (0x13) mode is selected, the TSR will reprogram the VGA timers to synch with 50hz instead of the default 70hz. This also works with ModeX-style modes. It's called vga2tv and you'll find a DOS
Of course, with Linux you can just use SVGATextMode to select any 50hz mode you'd fancy.
just my $0.02 etc. etc.
DOS on a TV box, posting errata (Score:1)
The DOS TSR I wrote is called "tvtsr", not "vga2tv"...
I tried this a loooong time ago. (Score:1)
I did not, however, have the luxury of a SCART I/F (damn North American TVs). I wired up a circuit to convert RGB to composite video and hooked it up to my TV.
I knew nothing of vertical and horizontal sync at the time and the picture looked scrambled, but I could tell that my C prompt was flying around in there.
It was only two years later when I dicovered SVGATextMode for Linux, but never tried it again because I lost the schematic and was too lazy to look for it again, but I'm almost sure it will work. X would probably work too.
I remember when every day, there was some guy asking for VGA-to-NTSC schematics on sci.electronics and the answer was always "you'll have to store the video and re-code it in NTSC, which will be expensive."
Hmmmm. You've got me thinking now, damnit. I might try it again on an old crappy video card. SVGATextMode even has an example NTSC text mode in the default config file. If STM works, so will X.
I originally found the circuit using an old DOS electronics magazine database called CSearch. It was a simple RGB-to-composite circuit that didn't require external power. I think you may still be able to find CSearch somewhere. If not, email me and I'll try to retrieve it from my old disk collection (I had a 100MB HD at the time so I used a lot of disks!).
Resources and info for any pc-to-tv project (Score:1)
Yes, it's quite possible, but not entirely simple.
Basically you would have to mix the video. There are other ways, though. Some do not involve a video card.
<sound of rummaging through various magazines>
All right, I'm back. Chips of interest:
Articles and columns:
Yes, Lancaster's titles are messed up, so is his website [tinaja.com]. He has a lot to learn about site design. Though he did invent the TV Typewriter.
All the articles should be there (save the first one, he didn't write that), somewhere, and may be hard to find. I found a couple with a quick search, though.
However, info from the semiconductor manufacturers is typically very good, and many offer free samples.
If anyone wants to attempt any of this, email me. I have experience with this kind of stuff and would be happy to help.
Re:Dunno how, but it must be possible... (Score:1)
--
Quick 'n' Dirty Hack... (Score:1)
I know this isn't what you want, but it may be fun to try!
I have been thinking about this myself, though I have a slightly easier channel - I bought one of those "Game Zapper" converters years ago when I had a 486 and Windows 3.1 - I used it to hook up a Victormaxx Stuntmaster to my PC for REND386 - now I want to do the same thing under Linux. Unfortunately, the "driver" was a DOS TSR program. The way I believe it works is by just changing the output frequency of the card, and the adaptor converts that to NTSC composite video. I have been thinking about mucking with it for a while to see if I can get something cheesy to work - I have also tried to contact the manufacturer for info (for the source, actually), since it is no longer manufactured, but I haven't got anything out of them yet...
Has anybody had any experience with this device?
Quick 'n' Dirty Hack... (Score:1)
I know this isn't what you want, but it may be fun to try!
I have been thinking about this myself, though I have a slightly easier channel - I bought one of those "Game Zapper" converters years ago when I had a 486 and Windows 3.1 - I used it to hook up a Victormaxx Stuntmaster to my PC for REND386 - now I want to do the same thing under Linux. Unfortunately, the "driver" was a DOS TSR program. The way I believe it works is by just changing the output frequency of the card, and the adaptor converts that to NTSC composite video. I have been thinking about mucking with it for a while to see if I can get something cheesy to work - I have also tried to contact the manufacturer for info (for the source, actually), since it is no longer manufactured, but I haven't got anything out of them yet...
Has anybody had any experience with this device?