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

[bacteria]

I have one of those NTSC PIF chips still which will hopefully allow me to make the PAL N64 output RGB.

I am however stuck in regards to systems like the SNES which is composite, as is the MegaDrive, Amstrad GX4000, NES. I had planned to use a RetroDuo for the SNES and NES but that would need a separate screen as it is NTSC. As I recall, I got RGB working on my PAL SNES, although the quality wasn't quite as good as composite - i'm also not sure if the PAL SNES can be made to take NTSC game carts? Can the MegaDrive 2 (ie the PAL version of the Genesis) be made to output RGB instead of composite?

[XCVG]

The Genesis/Megadrive will output RGB without a mod. A PAL SNES can take NTSC carts with a region mod and 50/60hz mod. That alone is another reason to use RGB. 50/60hz mods will screw up video, because it is possible to make the system (depending on system of course) output 50hz NTSC video (bad) or 60hz PAL video (works with some TVs).

[tom61]

I take it you've had no luck sourcing NTSC/PAL decoder chips? Perhaps going in two stages with digital conversion chips, one to decode composite to digital, and another to take digital and output analog RGB. I have a VGA box that does it's conversion this way, except the second chip up-scans the signal to 31kHz as well.

NES requires the chip from a Nintendo PlayChoice (Nintendo vs. had a slightly different palette, IIRC) arcade board to output true RGB.

[bacteria]

XCVG - I will look into that when I get onto those systems. Didn't realised the Megadrive could do RGB. Wonder if the SMS will too?

tom61 - what I ideally need is a conversion circuit that is small so it fits in the case, takes PAL composite and outputs RGB - if you know chips that can do it, or a small and cheap box that does it, please post!

[XCVG]

What about that TDA3566A mentioned earlier? It's not made anymore but I did a quick google and it's still possible to get, although it will run you $20 or so.

http://electronicpool.de/en/list/detail ... z=TDA3566A" onclick="window.open(this.href);return false;
http://www.4starelectronics.com/part_de ... 3566A.html" onclick="window.open(this.href);return false;

[bacteria]

Found datasheet on the TDA3566A

It is an NTSC/PAL decoder - doesn't mention about composite that I could see... (have a look)

[XCVG]

Okay, so not that one. Let's all keep looking, I saw one somewhere.

[tom61]

Found datasheet on the TDA3566A

It is an NTSC/PAL decoder - doesn't mention about composite that I could see... (have a look)

Does in mention CVBS? That's the same as composite. Since this is the chip in the composite to RGB converter I have, I'm positive it'll work in that capacity. Though it does have three supporting ICs and a large green thing labeled 300ns and 1000 Ohms.

[daftmike]

I don't think you will easily/cheaply be able to get hold of any of these chips, and designing an effective circuit for them is another matter altogether.

However, i have had to decode pal to rgb in the past and i have a spare circuit that should be exactly what you need. If memory serves, the board is about 100x50mm.

I've not had any free time in the last month for project work, but i can have a look at it this weekend if you still need it.

[bacteria]

After a lot of faffing about, I discovered that I could get RGB to work properly on my TurboGrafx, not via the HU6260 chip as is normal (although you often need to amplify the RGB and improve the C-Sync line) but straight from the PAL only TG-16 CXA chip on the board directly.

I have compared the RGB going to the Logic 3 screen and the official PSone screen - the official screen has better definition, and of course, it takes composite too so handy for other projects. This means I will stay with the official PSone screen; so don't need the Logic 3 screen.


It was mentioned before that RGB is exactly the same for NTSC and PAL, no different signals; so RGB on PAL is exactly the same as RGB on NTSC - is this true, or do RGB output in NTSC and PAL need different screens?

[daftmike]

There are several differences between PAL and NTSC video, one of which is the refresh rate, 50Hz for PAL, 60Hz for NTSC. This refresh rate also means a difference between the rgb signals.

For the most part PAL consoles will have a 50Hz RGB signal, and NTSC will be 60Hz.

A PAL Psone screen will not take the 60Hz RGB from an NTSC console and vice-versa.

[XCVG]

I guess there's the sync difference, but the colour signals are the same. Aren't most RGB devices somewhat multisync anyway?

[daftmike]

Yes, the issue is with the psone screen itself, it will not sync with different refresh rates, even over RGB unfortunately.