BigO Posted September 14, 2007 Share Posted September 14, 2007 Have any of y'all ever experimented with using the composite video or luma/chroma from the 7800's expansion port (or solder pads for the machines without the actual connector)? Quote Link to comment Share on other sites More sharing options...
Shawn Posted September 14, 2007 Share Posted September 14, 2007 Have any of y'all ever experimented with using the composite video or luma/chroma from the 7800's expansion port (or solder pads for the machines without the actual connector)? It's possible yes but I have not done it myself yet. It would require some work and an amp for the video as from what I have read the output is very weak. Quote Link to comment Share on other sites More sharing options...
BigO Posted September 14, 2007 Author Share Posted September 14, 2007 Have any of y'all ever experimented with using the composite video or luma/chroma from the 7800's expansion port (or solder pads for the machines without the actual connector)? It's possible yes but I have not done it myself yet. It would require some work and an amp for the video as from what I have read the output is very weak. Gracias, Sr. I'll take a look at the signal. What I'm thinking of feeding it into may be able to handle a weak signal okay. Quote Link to comment Share on other sites More sharing options...
Flipper Posted September 17, 2007 Share Posted September 17, 2007 Have any of y'all ever experimented with using the composite video or luma/chroma from the 7800's expansion port (or solder pads for the machines without the actual connector)? It's possible yes but I have not done it myself yet. It would require some work and an amp for the video as from what I have read the output is very weak. Gracias, Sr. I'll take a look at the signal. What I'm thinking of feeding it into may be able to handle a weak signal okay. Take a look at My 7800 expansion port attempt. It's quite doable, however I found the following issues. 1. When taking composite video from CVIDEO, the FM audio signal is mixed in at 4.5MHz or whatever it is for NTSC. The filter required to trap this signal without affecting the phase of the color burst that I was able to find a schematic for was over 30 components (cheap, but lots of soldering). I'm guessing when I do digital electronics, and analog I have no background in. 2. When taking video from the digital port and using a standard 2600 S-Video out mod, you get wonderfully clean video, but in 7800 mode only. The digital video is tapped before the OR gates that combine the TIA and MARIA, not after, so you only get the MARIA signals. I had hoped that an analog guy on here would pick up my efforts and run with them, but nothing ever got done. I wish you more luck! BTW, I think I have the algorithm for doing genlock on the 7800. Use RDY (on the expansion port) to gracefully halt the 6502, use EXTMEN to disable and enable MARIA briefly (documented to reset all sync counters), and then release RDY. A LM1881 would do the sync separation, but I don't know when a good time to pull RDY low would be. Mixing the signals is easy, just wait for LUM0-3 to be all 0, and cut the input signal through. Quote Link to comment Share on other sites More sharing options...
mos6507 Posted September 17, 2007 Share Posted September 17, 2007 Dude, your site got spammed. Quote Link to comment Share on other sites More sharing options...
Flipper Posted September 17, 2007 Share Posted September 17, 2007 Dude, your site got spammed. Thanx. Didn't happen that long ago, either. Quote Link to comment Share on other sites More sharing options...
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