SNES RGB to YUV (component YPbPr) conversion possible solution...

[kynrek]

I am trying to convert the RGB from an NTSC Super Nintendo system to YUV (component YPbPr for my tv) The SNES has R,G,B, Luma (S-video), Chroma (S-video), composite video, and composite sync outputs. The first time I tried I connected the Luma and ground for the Y input on the tv and R and ground for the PB input and B and ground for the PR input. It worked and the picture was clear (worked with and without the 220uf caps on each line on a Sony Wega tv (not flatscreen or lcd)) but the colors were not right (I understand now that RGB and Ypbpr are different). Since it all worked besides the correct colors I am guessing it's just that I just need R-Y instead of R on the pb and B-Y instead of just B on the pr, so it should just be a simple calculation i think.

I bought this IC that i think might do the trick: AN15851A description IC AV SWITCH 4 IN W/RGB-YUV CONV

http://dkc3.digikey.com/PDF/US2011/P1183.pdf

Do you think it will work (I should receive it in a few days)

[Fwirt]

I've been wondering about this same kind of thing. That IC is neat, but it looks like you need to talk to it over I²C to get it to start converting RGB to YUV. Also, it's an SMT IC, so unless you're comfortable with designing and etching your own boards, it might be tricky to use. I've seen a couple other solutions using discrete components, mostly just op-amps. See here and this datasheet, page 14. My question: is the RGB output of old consoles (Genesis/MD and SNES) progressive or interlaced? Either way, would the converted RGB signal work with the YPbPr input on most TVs? I'm under the (probably false) impression that YPbPr inputs expect progressive scan video data. It seems like some type of cheap converter like these would be the best solution to the problem of no RGB inputs on American TVs, as YPbPr quality is pretty darn close to RGB quality, but I'm curious whether most TVs would be able to sync with the output of these converters. I'm stuck with S-Video for the time being, and while it's worlds better than composite, I'd like to go a step further.

[kynrek]

Thanks for replying, Finally a kindred spirit!

I got 2 of the the ICs in the mail the other day. I haven't played with them yet but the pins are extremely small. I got some 22 gauge solid core wire and hopefully it will be small enough to use. What did you mean by "you need to talk to it over I²C to get it to start converting RGB to YUV"?

I have seen that first link you posted before (it takes me to yahoo.com when I click it though) but I didn't fully understand the schematic.

[Fwirt]

Well, I looked at the datasheet for the part you ordered, and on page 10 where the pin descriptions for the RGB input pins are it says, "Selectively controlled by IIC Bus to convert RGB to YUV." I think that means that it doesn't start out in that conversion mode by default. I could be wrong though, hopefully it will work for you.

It's odd that the schematic links to yahoo for you, the link works fine for me... What part of it were you having trouble understanding?