I'm thinking about a new component solution. I did my homework, and the common (useful) response is to use a VGA box and a VGA-to-Component box.
I could use that and be done with it, but I want a compact solution that doesn't add yet another power adapter to my equipment. And I don't need the upscaling you sometimes get.
So this is the well known VGA box circuit to switch on VGA mode:
And I found this circuit to convert RGB into YCbCr colourspace and add a component sync:
Again, I could just put them together and see how they work, but I'd like the best and minimum version.
So I assume people here have all built their own VGA box and did some experimenting, so I hope someone can answer my questions. Or at least probe some lines with an oscilloscope.
1) Does RGB select actually switch the DAC between RGB and Chroma/Luma/Composite mode? Yes Does the SCART cable pull this permanently low?
2) Does VGA select switch off composite sync, or is H/V sync disabled without the VGA switch?No Or is it only used to signal the software that a VGA box is connected and 480p can be safely displayed?
3) If C-Sync (pin 10) is always available, can it be directly added to the component output, so I can throw away all the gubbins that merge H and V sync? Does anyone have docs how component expects the sync?
4) If Luma (pin 12) is always available, can it be used directly for component Y? The math for both is the same ( Y' = 0.2126 R' + 0.7152 G' + 0.0722 B' ), though I can't find anything on the sync signal. Luma is not available
5) Does anyone know of good integrated circuits to do the RGB-YCbCr colourspace conversion, so I won't need a forest of resistors and op-amps? Or for the H/V to Composite sync merge? Or a good all-in-one solution?
6) If the VGA select switches between C-sync (pin 10) and H/V-sync (pin 8+9), is there a good way to use either as a sync source, so you can display both 480i and 480p with the same cable?C-Sync is available in both modes
Update: Luma is not available. Thanks!
Update: C-Sync. Thanks!