Direct Video and Sync on Green on VGA

Discussion about displays and related hardware including MiSTer filters and video settings.
Atohmdiy
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Direct Video and Sync on Green on VGA

Unread post by Atohmdiy »

Hello,
I want to know something before buying a cable.
I want to connect a guncon 2 to the io board's vga. I will only connect the guncon here because i am using direct video.
There is two cheap vga to rca cable i can buy, the first one is yuv cable, probably connected to the RGB line of the VGA.
Second is svideo composite and two audio. This should work, but it's probably the RGB and Sync line tie together, what i don't know is the level, because guncon wait for 1v (consumer composite) and the sync level alone out of io board is 3.3v if i am not mistaken. It will work but i am not sure of the tolerance of the guncon, higher voltage can destroy them over time.
Some seller offer vga to scart for the mister, and i think the 470 ohm resistor inside these is also used for their guncon rca out.

Anyway, if i set the sog switch to auto and vga_sog=1, i will have sync on the green line, so it should work and there won't be any problem with level. And it won't change anything to direct video right ? I still have RGBS ?

FoxbatStargazer
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Re: Direct Video and Sync on Green on VGA

Unread post by FoxbatStargazer »

Don't know what adapter to use, but I do know that turning on SoG 1) does not affect direct video, and 2) does not erase HV sync even on the VGA side.

Just using vga->component breakout should be simple? Since the same sync as composite will be there on the Green line?

Atohmdiy
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Re: Direct Video and Sync on Green on VGA

Unread post by Atohmdiy »

Yes a vga to component would work fine. Indeed the sync will be on green line.

I will try this :

https://aliexpress.com/item/33003670521.html

It's cheap and it's easy to plug in the rear of the io board.

I also made a few test and indeed the sog switch and vga_sog=1 do not seems to impact direct video. I think i read somewhere that composite_sync=1 is required for RGsB, i will make more test when i receive the adapter. The best for me would be RGBHV on direct video and RGsB on the io vga.

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Re: Direct Video and Sync on Green on VGA

Unread post by FoxbatStargazer »

composite_sync=1 has no interaction with RGsB, else you would need it on for component video (which is just ypbpr=1 and SoG). I think it just crams composite sync into either the H or V channel. Composite sync being completely different from sync-on-composite (zero chance for confusion there...) I think this article tries to explain.

Atohmdiy
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Re: Direct Video and Sync on Green on VGA

Unread post by Atohmdiy »

It should work then, i'll see when i receive the adapter. Thanks

Atohmdiy
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Re: Direct Video and Sync on Green on VGA

Unread post by Atohmdiy »

Hello,
I receive the adapter today. It wasn't working at first, as the chinese has the good idea to mess up the colors of the connectors... The blue connector is actually the green channel. Anyway, i can confirm this is working but only with composite_sync=1. Without it the guncon is moving top to bottom
So sync on green on vga require composite sync to work.

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Re: Direct Video and Sync on Green on VGA

Unread post by FoxbatStargazer »

Sounds pretty odd but glad you got it working.

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