Is there a chip/way to convert composite into RGB??

bacteria · Post by **bacteria** » Wed Apr 15, 2009 7:24 pm

I notice the original Playstation can convert RGB into composite (from one of the post topics) and the UK PAL TurboGrafx has a chip to also do that; however, what I would like is a way to convert composite into RGB.

I know obviously the output quality, if this were possible, would only be as good as the original source (composite) but would at least it would work on an RGB screen. Hopefully the quality wouldn't be worse than composite after conversion though.

Reasoning for this you ask? I have a Logic 3 PSone screen, which only takes RGB; although it handily has an NTSC / PAL switch. The screen is also nice. On systems that are only composite, if I were able to covert those signals into RGB I could use the same screen.

Ideas, and links please?

Dark-Aries · Post by **Dark-Aries** » Wed Apr 15, 2009 7:31 pm

repeat The signal into each line. It'd have a video for each line. Dunno obut the output though. Only other way is buying one of those pelican video convertor magigies I saw on Tehskeen one day...

bacteria · Post by **bacteria** » Wed Apr 15, 2009 7:59 pm

What do you mean - put the composite line into the R, G, B and C-Sync lines? Would that work??

Wouldn't that just give a black and white image, which is no use - I need colour!

Spent a while on Google; only came up with this: http://www.qsl.net/dl2rcg/fbas-rgb.html which is far from straightforward...

Post by **marshallh** » Wed Apr 15, 2009 9:13 pm

I bet if you look up the datasheet for the video decoder chip inside your screen, you'll find it will have input pins for composite and s-video. Most do.

There's no easy way to go from composite to RGB.

bacteria · Post by **bacteria** » Thu Apr 16, 2009 7:24 am

Ok, removed the shielding from the screen backing to get to the chips - there are only two chips present on the screen - found the datasheets on http://www.alldatasheet.com and downloaded the two files below. The chips are both Sharp, one is IR3Y26A and the other is LZ9GF16

Here is a screenshot of probably the relevant parts?

and other other chip:

The PDF files can be viewed here: IR3Y26A and LZ9GF16

So the question is: which pin to tap onto for composite? Is it pin 3 on the IR3Y26A or pin 9 on the other chip or is it something else entirely?? If marshallh is right from his last post, there must be a way...

XCVG · Post by **XCVG** » Thu Apr 16, 2009 9:19 am

It's possible. There are chips that will do it, but they are less common. And encoder chips in consoles do NOT have composite inputs. Unless it is really old (like a NES or 2600) the video is generated in RGB (digital) goes through a DAC, and then is encoded into other formats.

And what is the point of NTSC/PAL on an RGB-only display? RGB is RGB, there is no NTSC or PAL.

Post by **marshallh** » Thu Apr 16, 2009 10:43 am

Looks like RGB is all you're going to get. Pin 9 you were looking at is for composite sync (V-sync and H-sync combined), not composite video

eurddrue · Post by **eurddrue** » Thu Apr 16, 2009 4:49 pm

marshallh wrote:Looks like RGB is all you're going to get. Pin 9 you were looking at is for composite sync (V-sync and H-sync combined), not composite video

What? He wants RGB though

Dark-Aries · Post by **Dark-Aries** » Thu Apr 16, 2009 7:35 pm

eurddrue wrote:
marshallh wrote:Looks like RGB is all you're going to get. Pin 9 you were looking at is for composite sync (V-sync and H-sync combined), not composite video
What? He wants RGB though

He wants to plug his composite video system into an RGB screen. Since the screen can't take composite input, no go.

eurddrue · Post by **eurddrue** » Thu Apr 16, 2009 7:38 pm

Dark-Aries wrote:
eurddrue wrote:
marshallh wrote:Looks like RGB is all you're going to get. Pin 9 you were looking at is for composite sync (V-sync and H-sync combined), not composite video
What? He wants RGB though

He wants to plug his composite video system into an RGB screen. Since the screen can't take composite input, no go.

well, I did tell you Marshallh

bacteria · Post by **bacteria** » Thu Apr 16, 2009 8:19 pm

Reason I wanted to do this was that I intend to do my Version 2 Multi-Platform system, and it would have been nice to just need one screen section to take all games. Yes, I know the PSone screen does composite and RGB (!) however, three reasons I might use the Logic 3 screen - firstly, the screen is bigger - the visible screen area of a PSone screen is actually 132mm whereas the Logic three is 143mm; secondly, it appears from the limited testing I did (the C-sync was scrolling, I will fix that) that the image is clearer, no pixilation, brighter colours; thirdly, the screen board needs no trimming, it isn't even as large as the LCD - it has a couple of daughter boards but sure I can get those in ok.

So, that means I will use one screen front for RGB boards I have (only TurboGrafx, GBA, think my UK GameCubes can be RGB); everything else will be using a PSone screen section.

XCVG · Post by **XCVG** » Fri Apr 17, 2009 9:06 am

Well if you are going to mod the consoles anyway, you might as well do RGB mods. With mod the SNES mini, N64, and a few others can do it.

themadhacker · Post by **themadhacker** » Fri Apr 17, 2009 11:23 am

I thought PAL n64 systems didn't support RGB

tom61 · Post by **tom61** » Fri Apr 17, 2009 1:06 pm

There should be chips to do NTSC/PAL video decoding by themselves. I have a board with a handful of chips on it to do what you're talking about, to put composite video on my arcade machine (I do have the schematics for it, but the chips used are obsolete, discontinued, and unfindable last I looked). You might be able to find a suitable decoder board in the arcade section of eBay, as they're needed to fit a LaserDisc game (like Dragon's Lair) into a normal arcade cabinet. It will probably take some effort to find one small enough for your usuage, or with few components to be fitting onto a smaller board.

Edit:
Maybe you can find the chips easier than I can so, here's the datasheet for the main decoder chip on the board I have:
http://www.datasheetcatalog.com/datashe ... 566A.shtml" onclick="window.open(this.href);return false;

You might try looking on Philips' semiconductor website and see if they have an updated version.

XCVG · Post by **XCVG** » Fri Apr 17, 2009 8:20 pm

themadhacker wrote:I thought PAL n64 systems didn't support RGB

They don't. But if you swap the PIF chip on an NTSC board with a PAL one you can use PAL games. A 1337 h4x0r like Bacteria could easily do it.

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