Getting the NES master clock signal to drive a video encoder

[Drakon]

In pretty much all retro consoles everything is driven by the same clock signal. However the av famicom rgb / s-video kits have the video encoder driven by a separate crystal oscillator. Driving the video encoder from the same clock signal as everything else greatly improves the video quality. The nes clock signal is 6x as fast as what's needed to drive a video encoder in ntsc mode. I worked with tiido to help me figure this out (the creator of the sega genesis crystal clear audio mod). Both me and tiido found the same schematics on the internet and tiido helped find me the right parts to use and explained the basics of how to wire the ICs up. I bought the ICs and wired them up and the circuit indeed worked right away. The difference is extremely noticable the s-video image quality now looks absolutely pixel perfect. Here's the circuit I built:

I grabbed the system clock signal from ppu pin 18 thanks to the nesdev ppu pinout sheet. Here's some comparison screenshots...it's a bit hard to notice the improvement from the screenshots but on my tv it's greatly improved:

 

[Bibin]

Re: Getting the NES master clock signal to drive a video enc

Aha, awesome. Leave it to tiido to figure out discrete logic for these things!

Are there any good sources for getting an RP2C03B yet? I still don't want to fork over the cash for a playchoice board and Vs. Duck Hunt and tennis are hard to come by.

 

[Prog]

Re: Getting the NES master clock signal to drive a video enc

Sick man!
I wish I had half of either of your skills.

 

[Drakon]

Re: Getting the NES master clock signal to drive a video enc

There's no good sources of the nes rgb ppu. Here's what happened....

Back in the day before I started offering the service of building these rgb systems you used to be able to get playchoices from 50-80$ shipped including the ppu chip. I built up a small collection of them, started offering my service, and watched people on the internet start rabidly hoarding playchoice rgb chips and av famicoms off of ebay. I resold all of my extra rgb chips for a small profit. Now everyone is coming to me like I have some sort of super secret connection to cheap rgb chips, lately everyone and his dog has been approaching me about helping them find cheap rgb chips. Atleast the way you ask doesn't make it sound like you expect me to have connections to a cheap supplier. The only reason my rgb chips didn't cost an arm and a leg was because until I showed up offering my service the rgb systems floating around weren't the greatest. The rgb modded systems before me came with video jailbars, video issues like a flickering backgrounds, not the greatest "stereo sound" mods, and no s-video or multi av ports. I get a lot of people approaching me wanting me to take the rgb chip from their old rgb modded nes that someone else did and build them a far superior rgb av famicom. In conclusion the internet has been pretty much bled dry of affordable playchoice rgb chips because of the popularity of what I've done. In fact the two most recent systems I've been commissioned to build both are using the rc2c05-04 ppu which requires a custom circuit just to get this chip working. The 05-04 ppu used to be way harder to get than the playchoice ppu....not so much anymore I guess.

And yes working with tiido has helped me accomplish a lot of things I never would have figured out. Tiido is the greatest and he's always willing to help me out with my ideas.

I also forgot to post that I've upgraded the kit to use the cxa2075 for the best video sharpness and colour encoding quality.

 

[grossaffe]

Re: Getting the NES master clock signal to drive a video enc

that's gotta be pretty cool knowing you single-handedly influenced the market with your work.

 

[Drakon]

Re: Getting the NES master clock signal to drive a video enc

that's gotta be pretty cool knowing you single-handedly influenced the market with your work.

I suppose. But now I can't find cheap av famicoms or rgb ppus anymore.....

 

[Bibin]

Re: Getting the NES master clock signal to drive a video enc

Ack, how unfortunate - I fear I'll never be able to find the PPU affordably now :/