Build Your Own Arcade Controls Forum

Software Support => GroovyMAME => Topic started by: oldgamer on August 07, 2019, 05:53:52 pm

Title: Does the csync crt_emudriver feature work if I use digital to vga dongle?
Post by: oldgamer on August 07, 2019, 05:53:52 pm: Hi everyone.

So I learned it is possible to have the AMD cards output composite sync instead of HV which can help if you want to connect your PC to a TV/RGBS monitor.

But does the csync/composite sync feature work if I use a displayport/HDMI to VGA adapter instead of native VGA/DVI-I?

My first guess is that the answer is no- this would only work for native VGA/DVI-I output.

Hoping I'm wrong though.
Title: Re: Does the csync crt_emudriver feature work if I use digital to vga dongle?
Post by: Calamity on August 08, 2019, 06:49:37 am: I've never tried, but I'd say it should work.
Title: Re: Does the csync crt_emudriver feature work if I use digital to vga dongle?
Post by: Doozer on August 08, 2019, 07:40:38 am: Chips used onboard those adapters will deliver H+V from HDMI not CSYNC based on my experience. But an additional mixer or some resistors can turn the two signal into one suitable for composite sync. The circuit depends on the voltage level and screen signal tolerance.
Title: Re: Does the csync crt_emudriver feature work if I use digital to vga dongle?
Post by: oldgamer on August 08, 2019, 04:52:24 pm: Quote from: Doozer on August 08, 2019, 07:40:38 am

Chips used onboard those adapters will deliver H+V from HDMI not CSYNC based on my experience. But an additional mixer or some resistors can turn the two signal into one suitable for composite sync. The circuit depends on the voltage level and screen signal tolerance.

My hope was to use "native" csync exactly to avoid having to build the sync combiner.

Even if I buy a ready made sync combiner it might have some kind of flaw/limitation (even if minor ones).
Title: Re: Does the csync crt_emudriver feature work if I use digital to vga dongle?
Post by: oldgamer on August 08, 2019, 04:55:59 pm: I will buy the parts and attempt to build a vga to SCART (horizontal sync vga to csync on the scart side) cable. I have someone who can lend me an AMD card, then I will test the whole thing and report back.
Title: Re: Does the csync crt_emudriver feature work if I use digital to vga dongle?
Post by: m.andrade1 on August 09, 2019, 08:36:34 am: Hello Oldgamer
That will be very interesting, i have some RGB osd mod tv, today i used them thru vga with a 1k in each H and V them twisted toghter on AV sync of the tv, some sets works great, others produces some jailbars effect, i´m very interesting on that solution, to make a only H to sync to tv, to try to avoid issues like that.
Thanks
Marcos