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Main => Monitor/Video Forum => Topic started by: sittingduck on February 01, 2006, 06:24:38 am

Title: Using guncon chip as signal divider
Post by: sittingduck on February 01, 2006, 06:24:38 am

I already have an AVGA in a Mame machine and am pleased with it, but for different reasons I would like to use a regular graphics card and a scart tv in my next machine. However, I'd like to be able to view the boot up screen and this wouldn't work as the gfx card outputs 31khz and the tv only works with 15khz.

So I need to halve the signal during boot. I believe that this is doable by using Ultimarc's Z-GUN Chip. See the last item on this page:http://www.ultimarc.com/JShopServer/section.php?xSec=5 (http://www.ultimarc.com/JShopServer/section.php?xSec=5). However, as this chip is meant for use with Guncons, can anybody confirm that this circuit will actually accomplish what I'm looking for? And how will the circuit act once my 15khz resolutions load up after booting - does it then "go to sleep"?

Title: Re: Using guncon chip as signal divider
Post by: Silver on February 04, 2006, 10:09:01 am

you can email andy warne to check, but I don't think so. It's deigned to feed at 15Khz sync to gun while you have a 31Khz monitor in use. So it will give you a 15Khz sync, but not a 15Khz picture (it does not touch RGB)