[mythtv-users] [ G400 ] Hotwo enable flicker filters

[Bernd Müller]

Hello;

O.k. i will try the cable like this:

      VGA                                          SCART

     1 -O------------------------------------------O- 15 R
     6 -O------------------------------------------O- 13 R Gnd

     2 -O------------------------------------------O- 11 G
     7 -O------------------------------------------O-  9 G Gnd

     3 -O------------------------------------------O-  7 B
     8 -O------------------------------------------O-  5 B Gnd

    13 -O------------------------------------------O- 20 csync
    10 -O------------------------------------------O- 17 csync Gnd

shell -O------------------------------------------O- shell

The bridge between PIN 5 and 11 was described as "The link between 5 (Gnd) and 
11 (Mid0) tells your VGA card that your `monitor' is colour". But i will omit it.

Making the cable as short as possible, is a little bit difficult in my case. My 
MythTV Box and the tv are in different rooms. The minimal cablelength i need is 
8 meters (~ 26 ft). I do this as a due to noise reduction. I know that this i 
very problematic. To keep the loss as minimal as possible i'm using a special 
RGB cable. Each of the 5 wires is shielded, this means is coaxial. Additionally 
the whole cable is also shielded, too. My electronic dealer advertises it as 
"High Quality Monitorcable. 5x 75 Ohm coaxial  single and overall shielding". I 
did not find any better shielded (and even more expensive ;-) cable for this 
task. So i'm in hope i will work for me.

Wow, it's really amazing. I've read so many tutorials about tv-out and the G400. 
But in no one i've read about this type of cable. I think, if it will work for 
me, i will write a small howto about it.

(c; bernd

Cory Papenfuss schrieb:
>> VGA                                                SCART
>>
>>   1 -O------------------------------------------O- 15 R
>>   2 -O------------------------------------------O- 11 G
>>   3 -O------------------------------------------O-  7 B
> 
> 
>     RGB signals, yes
> 
>>
>>   6 -O------------------------------------------O- 13 R Gnd
>>   7 -O------------------------------------------O-  9 G Gnd
>>   8 -O------------------------------------------O-  5 B Gnd
>>
>     RGB grounds, yes.
> 
>     If possible, keep these lines as short/clean as possible, and do not 
> connect all the grounds together anywhere.  You may even try to use 
> coaxial cable or something for them.  This is pretty high frequency 
> (although not nearly has high as for a computer signal).
> 
> 
>>   5 -O-+
>>        |
>>  11 -O-+
>>
>     I don't know what this is for... it might be a matrox-ism.All I see 
> is Ground and No Connect, so I wouldn't do it if you want to make a 
> generic VGA cable.
> 
> 
>>  10 -O------------------------------------------O- 17
>> Gnd
> 
> 
>     Sync GND, yes.
> 
>>
>>  14 -O------------------------+
>> -VS                           |
>>                               |
>>  13 -O------------------------+-----------------o- 20
>> -HS                                               -CS
>>
>     Here's what you probably don't want to do.  Connecting VGA HSYNC and 
> VSYNC together like that means they'll try to drive each other. That's 
> what the transistor circuit is for.  Generally, if a video card supports 
> CSYNC, it'll come out on the HSYNC pin.  So, just connect VGA13->SCART20 
> and leave VGA14 unconnected.
> 
>> 5,6,7,8,Shell ------------------------------------ 5,9,13,17,21,Shell
>>
> 
>     I wouldn't run the video GNDs to the shell.  Leave them point-to-point.
> 
> 
>> Doing the math for the geometry and the timings should be no problem. 
>> The thing i'm not clear about is what the flags csync, hsync, vsync, 
>> bcast and so an are to be used for. At this point I would understand 
>> if you say RTFM  and i will do, but maybe you can wrote some words in 
>> general. I know what the hsync and vsync signals are for. But what 
>> will the options in the XF86Config modline will do?
>> A simple enable/disable?
>>
> 
>     The syncs can be either polarity... nominally 0 and then 5v (+Xsync) 
> when triggered, or nominally 5v and 0 (-Xsync) for trigger (X = h|v|c).  
> The flags just control their polarity.  The csync flag tells a supported 
> card to put out *BOTH* HSYNC and VSYNC out the HSYNC wire (XOR'd I 
> believe).  The bcast is a framebuffer-specific option that I don't think 
> many/any cards actually support.
> 
>     The hsync/vsync flags in the modeline don't enable/disable them... 
> just change the polarity.  The lack of those options just mean default 
> (+ I think).
> 
> -Cory
> 
> *************************************************************************
> * Cory Papenfuss                                                        *
> * Electrical Engineering candidate Ph.D. graduate student               *
> * Virginia Polytechnic Institute and State University                   *
> *************************************************************************
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> mythtv-users mailing list
> mythtv-users at mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users