Dreamcast 240p with gbs-c, setup advice.

[Guile]

I'd like to integrate my gbs-c into my setup for downscaling Dreamcast to 240p but I would like some advice on a good way to set it up. The gbs-c is currently connected to an ossc by the db-15 port. I use a manual vga switch to input either Dreamcast or gbs-c on that port.

The main problem is the need to feed rgbs to the gbs-c so I need to use an rgb interface. I considered just using a transcoder to get component from the Dreamcast but I think I prefer the vga output though I need to test that more. That's also a problem because most of my systems output component so I'd need to also move stuff around or get another switch for the ossc component input.

The options I'm thinking of are either using a Crosspoint matrix that I'm not using right now or a vga matrix. The problem with a Crosspoint is that it would require a bunch of vga to bnc cables and the cost will add up quickly. With a vga matrix I should have enough cables and I think it could also pass component if I need to. It would be nice to make a sort of magic box with the rgb interface and transcoder connected so I can output almost any format.

I guess I could also make another gbs-c for 240p only which might be the cheapest option but then it's another thing to plug in. Any advice on the best options?

[Syntax]

This is the proper sync combine circuit for Dreamcast by Viletim

http://etim.net.au/temp/forum/dreamcast ... _csync.pdf

[Shelcoof]

get yourself a scart cable that has a switch
you can get one from a retro consoles UK or retro gaming cables

This way you can have all three resolutions without issues
240p
480i downscale
480p downscale

[Guile]

This is the proper sync combine circuit for Dreamcast by Viletim

http://etim.net.au/temp/forum/dreamcast ... _csync.pdf

That looks very interesting but I don't have the knowledge or skills to build that. I will look into it some more and maybe attempt it someday if I can figure it out. On the bottom it says the chip 74HC123N is obsolete and a different timing resistor on R18 is needed. How do you figure out the proper replacement resistor? What do those numbers terminating with the X mean?

get yourself a scart cable that has a switch
you can get one from a retro consoles UK or retro gaming cables

This way you can have all three resolutions without issues
240p
480i downscale
480p downscale

I'm thinking of getting a cable that can switch or try to make one for the few games that don't support 480p. I want to downscale to 240p though so the cable alone couldn't do that, only show native 240p games as I understand it.

[Shelcoof]

get yourself a scart cable that has a switch
you can get one from a retro consoles UK or retro gaming cables

This way you can have all three resolutions without issues
240p
480i downscale
480p downscale

I'm thinking of getting a cable that can switch or try to make one for the few games that don't support 480p. I want to downscale to 240p though so the cable alone couldn't do that, only show native 240p games as I understand it.

The one Scart Cable alone can't downscale but paired with the GBS-C it can
The cable can switch between 15khz and 31khz
Switch it to games that can't output 31khz 480p

I have my Dreamcast set-up the same way with a GBS-C

When you set the GBS-C to downscale 240p

480p -> downscale to 240p
480i -> downscale to 240p
240p -> Passthru

Hope that helps

Forgot to mention my one of my GBS-C has SCART input
I know some GBS-C does not