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Connecting VGA-cards to TV?
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?"
Look at http://www.sput.webster.nl/hardware/tv-x.html
There are some plans for a simple vga-to-scart conversion (requires X to get the correct output though) There are also a few VGA-to-NTSC converters out there if you need the text mode, although they tend to be a little expensive.
Try the following URL. I tried the circuit myself, and got the picture on TV. My graphics card just could not reach frequencies low enough, so I did not get a stable picture or got a stable picture but two screens at the same time. Check if your card can produce the freqs needed. There are also links to similar projects.
2 tv/cindex.html
http://www.hut.fi/Misc/Electronics/circuits/vga
I bought a module for my matrox G200 a while back that does tv-out. It has a setting in the bios which sends a signal to the tv and to the monitor as well. It seems to find a mode that works for both TV and computer.
Anyway, this output works fine for dos, linux CL, and video modes like that. Also it has a windows utility that is able to change the video mode so that windows is output to the tv and the monitor (although again it looks strange on the monitor). This works for 640x480 800x600 and 1024x768. It seems to be just changing video modes and sync frequencies.
When attempting to get the tv-out to work under X (with my normal monitor modeline settings) all that is output to the tv is a white screen. I tried for a while to find modeline settings that would work for NTSC, but I was unsuccessful. However, I still think that it's only a matter of finding the correct modeline settings. All of the NTSC specs that I found on the internet and tried to convert to modeline didn't work though. If matrox was kind enough to give out the settings that they use for windows i think it would work.
At this point I've pretty much given up on this, but if anyone has any suggestions please email me
jeos
Get an Amiga, and 3 fast analog signal switchers ( 2 input , 1 output , 1 control input ) :-)
Convert the TV/video signal to RGB ( if not already in that format ).
Connect the vsync & hsync signals from video to
amiga sync inputs ( maybe se a bit in the amiga video hardware ).
Connect the R video signal to one input of one switch.
Connect the R computer signal to the other input.
Connect the output of the switch to the monitor/TV.
Do the same with G and B.
connect the original sync lines to monitor.
Connect the PIXELSWITCH signal from amiga to control all 2 switches. Not set another bit in the amiga gfx hardware to make the background color transparent and draw some logo or text
I've been meaning to try this for months. ...
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
^..^ OO (oo)
Won't apologize for shouting, it's appropriate in this instance.
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.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
would it be possible to have sort of "on screen programming" coming out of a linux box? Like, having the regular TV channel being watched but have a small line of text being displayed by the linux box, while not using a regular off the shelf vga-to-tv type of video converter...
The basic sleazeware produced in a drunken fury by a bunch of UCBerkeley grad students was still the core of BIND. --PV
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.)
Another non-functioning site was "uncertainty.microsoft.com."
The purpose of that site was not known.
1) you need to figure out how to connect rgb to
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.
Some time ago, I bought a miro hiscore 3dfx PCI grpahics card second-hand, and discovered (to my surprise) that it also featured a composite video out plug (is that's what it's called?)
.COM and the assembly source on my homepage, http://xcene.flipp.net (under "releases").
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.
-- close but no sig
Damn it, it's monday and I think I still have a hangover =)
The DOS TSR I wrote is called "tvtsr", not "vga2tv"...
-- close but no sig
I tried this when I was 14 and half-succeeded.
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!).
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. 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.
I remember seeing somewhere once a guy got a PIC to do "graphics" in black and white on his TV by toggling one of the output pins real damn fast, and hooking that up to the composite video in on the TV (I don't think it was a direct connection, but more of a level shifting transistor driver connection circuit) allowing him to create a game of pong. From what I understand, the output wasn't great, but it worked.
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?
Reason is the Path to God - Anon
I remember seeing somewhere once a guy got a PIC to do "graphics" in black and white on his TV by toggling one of the output pins real damn fast, and hooking that up to the composite video in on the TV (I don't think it was a direct connection, but more of a level shifting transistor driver connection circuit) allowing him to create a game of pong. From what I understand, the output wasn't great, but it worked.
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?
Reason is the Path to God - Anon