Two types of Dreamcast RGB

The place for all discussion on gaming hardware
Post Reply
User avatar
antron
Posts: 2861
Joined: Wed Feb 22, 2006 7:53 pm
Location: Egret 29, USA

Two types of Dreamcast RGB

Post by antron »

Does anyone know what the difference is between the two types of RGB signals that the DC can output?

http://www.gamesx.com/wiki/doku.php?id=av:dreamcastav
PC Engine Fan X!
Posts: 8455
Joined: Wed Jan 26, 2005 10:32 pm

Re: Two types of Dreamcast RGB

Post by PC Engine Fan X! »

antron wrote:Does anyone know what the difference is between the two types of RGB signals that the DC can output?

http://www.gamesx.com/wiki/doku.php?id=av:dreamcastav
Yes, the Dreamcast can output in both Japanese RGB & European SCART -- both use the same 21-pin styled plug connector but with different pinouts. I've got a pair of Japanese RGB 21-pin for my DC & PS2 consoles for use with the XRGB-2 upscan convertor setup.

PC Engine Fan X! ^_~
neorichieb1971
Posts: 7680
Joined: Wed Jan 26, 2005 1:28 am
Location: Bedford, UK
Contact:

Post by neorichieb1971 »

I think the link is referring to RGB vs VGA!


The difference between RGB and VGA is approx double the resolution. So if you buy a VGA box ($15) for your Dreamcast and connect it to your PC monitor you will see your games like never before.

Not all games are compatible, but most are.


Older TV's were never able to display resolutions as high as VGA monitors, RGB is about as good as it gets on TV's, and thats only if you live in Europe.
This industry has become 2 dimensional as it transcended into a 3D world.
User avatar
nZero
Posts: 2605
Joined: Wed Jan 26, 2005 1:20 am
Location: DC Area
Contact:

Post by nZero »

neorichieb1971 wrote:I think the link is referring to RGB vs VGA!
gamesx wrote:The select pins are 6 and 7. Ground either one for two kinds of 15kHz RGB, ground both for VGA.
Image
User avatar
Dave_K.
Posts: 4567
Joined: Wed Jan 26, 2005 5:43 am
Location: SF Bay Area
Contact:

Post by Dave_K. »

gamesx wrote:The select pins are 6 and 7. Ground either one for two kinds of 15kHz RGB, ground both for VGA.
I've never herd of this before, and I'm faily certain this was not on gamesx before they switched to a wiki. EURO Scart and JAP RGB use the same DC pins, just rewire to the scart end differently.
User avatar
SAM
Posts: 1788
Joined: Fri Jun 03, 2005 5:27 am
Location: A tiny nameless island in South China Sea

Post by SAM »

Really. :shock:

I thought SCART and Japanese 21-pins RGB cable just connected to different pins of the DC AV out jack. :o

Yes, I know that if you short certain pins of the DC AV out jack, would make the system output VGA. :)
*Meow* I am as serious as a cat could possible be. *Meow*
neorichieb1971
Posts: 7680
Joined: Wed Jan 26, 2005 1:28 am
Location: Bedford, UK
Contact:

Post by neorichieb1971 »

Japanese RGB and SCART, from the consoles perspective is exactly the same signal. So the console will output from the exact same pins. Its only the 21 pin side which is re-arranged (for some strange reason).

I think its stupid the pins are re-arranged personally, there is no logic to it.
This industry has become 2 dimensional as it transcended into a 3D world.
User avatar
antron
Posts: 2861
Joined: Wed Feb 22, 2006 7:53 pm
Location: Egret 29, USA

Post by antron »

yeah,
if the goal was to make any scart cable usable on any tv, you would still need different cables to make the proper selection on pins 6 and 7! (unless the cable had dip switches)
User avatar
matt
Posts: 596
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Post by matt »

Dave_K. wrote:
gamesx wrote:The select pins are 6 and 7. Ground either one for two kinds of 15kHz RGB, ground both for VGA.
I've never herd of this before, and I'm faily certain this was not on gamesx before they switched to a wiki. EURO Scart and JAP RGB use the same DC pins, just rewire to the scart end differently.
Not sure exactly what the page is referring to, but might probably not Euro vs JAP scart.

The mode select pins are tricky on the DC. Normally, pin 6 is grounded on DC RGB cables, and both pins 6 and 7 on VGA boxes. But, there are a few games that don't run at 15khz in this configuration (eg Skies of Arcadia) but can be tricked into working by switching off pin 7 after the game boots. They may be referring to something along these lines.
User avatar
antron
Posts: 2861
Joined: Wed Feb 22, 2006 7:53 pm
Location: Egret 29, USA

Post by antron »

So having a cable with a toggle switch does have an advantage.

I have been reluctant to order a scart cable to mod because I fear that pins 6 and 7 will be inaccessible (in molded plastic).

Any recommended brands?
User avatar
matt
Posts: 596
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Post by matt »

VGA boxes have both pins 6 and 7 accessible, but you only get H and V sync this way - no composite sync.

The only perfect way to manipulate both RGB selection pins is to install switches into the console. There are only a few games that require this, however so it may not be worth it.
User avatar
antron
Posts: 2861
Joined: Wed Feb 22, 2006 7:53 pm
Location: Egret 29, USA

Post by antron »

matt wrote:VGA boxes have both pins 6 and 7 accessible, but you only get H and V sync this way - no composite sync.
are you saying that pin 10 is not accessible in the VGA box? or does the composite sync turn off in VGA mode?

i think you can run H and V through an xor gate to get composite sync.
or the quick and dirty way: twist them together.
User avatar
matt
Posts: 596
Joined: Mon May 09, 2005 5:46 am
Location: Honolulu, Hawaii

Post by matt »

Because VGA monitors don't use composite sync, it's generally not connected in VGA boxes.

I haven't had much luck joining the DC's H & V sync lines (but I also haven't tried very hard). Maybe your monitor will like it a little better than mine.
Post Reply