MiSTer not working with BVM CRT

Discussion about displays and related hardware including MiSTer filters and video settings.
misterrocks
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Re: MiSTer not working with BVM CRT

Unread post by misterrocks »

I think I get it now. The signal is digital coming off of the MiSTer so you can convert it to analog with the IO board or with an external DAC using Direct Video mode.

FoxbatStargazer
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Re: MiSTer not working with BVM CRT

Unread post by FoxbatStargazer »

Whether using analog I/O or direct video, its the same process: a digital video signal has to be converted to analog once at some point. The only thing that changes is whether the I/O board or your HDMI->VGA converter does the DAC. Your PVM should just directly turn the analog into light so its not like its converting back to digital or anything. (unless its a dreaded HD-CRT but it seems not to be.)

Lag is effectively zero with either output style (when done right), when connected 15khz output to non-digitizing CRTs you will be able to play with the NES zapper over SNAC, so you know its good.

d909
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Re: MiSTer not working with BVM CRT

Unread post by d909 »

Can you really send composite sync over hdmi? I thought the composite_sync option on MiSTer was only for the analog I/O board. I'd assume your external DAC is generating normal VGA H+V sync regardless of that setting. So I'm actually surprised you get a usable signal with the HD Fury at all, unless it's just generating some kind of csync itself.

If you want to use direct video hdmi -> VGA, the way to get csync that I KNOW works well is an Extron RGB device (109xi, 203rxi, etc).

But I just use the analog I/O board.

NYI
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Re: MiSTer not working with BVM CRT

Unread post by NYI »

d909 wrote: Wed Sep 06, 2023 4:55 am

Can you really send composite sync over hdmi? I thought the composite_sync option on MiSTer was only for the analog I/O board. I'd assume your external DAC is generating normal VGA H+V sync regardless of that setting. So I'm actually surprised you get a usable signal with the HD Fury at all, unless it's just generating some kind of csync itself.

If you want to use direct video hdmi -> VGA, the way to get csync that I KNOW works well is an Extron RGB device (109xi, 203rxi, etc).

But I just use the analog I/O board.

Yes, you can get composite sync using a HDMI -> VGA adapter, will send H+V over the H line with composite_sync=1.

OP, you need to use the analog card in your BVM. Composite_sync should be set to 1, and direct video to 1, as you have.

I will let you know that whether you get a usable picture from direct_video when you boot up the MiSTer can depend on the HDMI -> VGA adapter. In my experience, I actually did not get a picture when booting up MiSTer using a Ugreen HDMI -> VGA adapter, but if I remoted into the MiSTer using SSH and manually started a core such as Genesis, I would. When I tried using a Tendak adapter instead, I got a picture with the main menu, but not with some of the cores. So some of the DACs can be tricky with what they will accept. Try a different HDMI -> VGA adapter. Also, where the R, G, B lines connect will line up with the monitor's labels, but either the black or the grey will end up going into the sync in - I suspect it should be black but it's a possibility it could be grey.

Your experience with a double picture divided down the middle was due to inputting a 480p source while your BVM is expecting max 480i.

You do not need an analog IO board.

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