video chip help!!

werejag · May 3, 2005

would this chip el1881cn work for converting neo geo mvs video to vga? if so how do i wire it up.

pdf - http://www.intersil.com/data/fn/fn7018.pdf

please help

werejag · May 4, 2005

so no one wants to help. thanks

stuffmonger · May 4, 2005

werejag said:
so no one wants to help. thanks

I'd help, but honestly, i don't know whether it would work or not...

JMKurtz · May 4, 2005

That's the same as an LM1881 -- it's used for splitting composite sync into H & V sync. Unless your monitor supports 15kHz video, it's not going to do you any good.

Jeff

werejag · May 4, 2005

damn so ill have to find another chip

werejag · May 5, 2005

was looking for a solution i could buy parts and solder together

stuffmonger · May 5, 2005

I think you may need an upscan converter... the x-rgb2 is the best one I think(although I personally don't have one) They're pretty expensive though (will probably set you back around $300, and you'll still need to convert the mvs output to scart pinout.

werejag · May 5, 2005

scart is not a usa thing and i did want vga. so i can use a 17inch lcd. 300 bucks is 275 bucks way to much for just video

werejag · May 6, 2005

so no one knows how to make one of these convertors ?

JMKurtz · May 6, 2005

Unless your monitor supports 15kHz, you *will* need a singal converter. You're not going to buy a simple IC, hook up a couple wires, and have it go...

If you want something cheaper that the X-RGB2, there are some cheap units out there that allow you to hook up devices to your PC monitor. I've seen some as low as $40 -- but be forewarned, the quality will suck ass as most of these cheaper ones only allow composite or SVideo.

Jeff

Dean · May 6, 2005

Jeff is right. People think that things should be dirt cheap because they don't really understand the equipment and parts involved. VGA is not cheap to get just because computers can output it. Realize that the circuitry involved is produced on a larger scale so you can amortize the cost of building/developing the circuit and the cost of parts is then at a huge volume discount.

You will not find a better solution than the XRGB-2. The cheap units don't actually upscan anything.

werejag · May 6, 2005

a sony cxa1645 or CXA2075 is expensive? vga is simple after you get to svideo specs.

with these chips i will get svideo and vga

dogtoy · May 7, 2005

werejag said:
a sony cxa1645 or CXA2075 is expensive? vga is simple after you get to svideo specs.

with these chips i will get svideo and vga

No.

What you will get with a cxa1645, cxa2075, cxa1145, ad725, ad724, etc. .....

is RGB to composite (CVBS) or svideo (Y/C) encoding.

Which is not even close to VGA.

VGA is RGB video but with a different horizontal sync rate.

What you need is a scan doubler. Good luck building one, and it is fairly expensive.

cheers,
-DT

Dean · May 7, 2005

werejag said:
a sony cxa1645 or CXA2075 is expensive? vga is simple after you get to svideo specs.

with these chips i will get svideo and vga

I would also like to quote this and state as dogtoy did, that NO, this is not the case.

What makes you think this is so simple?

werejag · May 7, 2005

D-Lite said:
I would also like to quote this and state as dogtoy did, that NO,
this is not the case.

What makes you think this is so simple?

as with the ps2 vga cables witch was made from a compsite cable. use the el1881
chip and it out puts svideo and vga when wired to the 15 pin connectors. this i
have done for my ps2

since this circuit does use the el1881 like the ps2 cable i made, it too should
output vga

well i am just trying to understand but getting info from here has been a problem.

i keep getting told use google when the answer can be easliy given.

help me learn please

Dean · May 7, 2005

I've found some info on the PS2 one as well, looking over at gamesx.com, but no where does Neo -> RGB exist. I believe this is due to the fact that the 15 kHz sync from a Neo is not compatible with VGA, just like other arcade boards. Perhaps that is why.

Honestly, you want an answer to this question go to www.gamesx.com Many of the techies from here are there too, but those folks are much much MUCH more hardcore video people that here.

dogtoy · May 7, 2005

werejag said:
as with the ps2 vga cables witch was made from a compsite cable. use the el1881
chip and it out puts svideo and vga when wired to the 15 pin connectors. this i
have done for my ps2

since this circuit does use the el1881 like the ps2 cable i made, it too should
output vga

well i am just trying to understand but getting info from here has been a problem.

i keep getting told use google when the answer can be easliy given.

help me learn please

The reason why the circuit you linked to above will work for the ps2 is that the ps2 video hardware can be forced to output a horizontal sync that is compatible with VGA (about 32 khz). This is not possible with neo-geo hardware.

To use the ps2 circuit above you either need to use ps2 linux or special software (looks like maybe a special modchip can do it also?). Or if you are lucky and happen to have a VGA monitor that will sync at 15KHZ (most will not).

For this to work with a neo-geo you will need some hardware to double the sync rate of the horizontal sync output. Your best bet is to buy something like xrgb-2. There are cheaper versions but I don't know how well they work.

Also you will get a much better, more stable picture if you use two gates on the composite sync line from the lm1881 to get an actual horizontal sync before you connect it to the HSYNC on your VGA monitor. As described on this page:
http://www.epanorama.net/documents/vga2rgb/vgamonitor.html

Hope this helps.

cheers,
-DT

For info about the x-rbg2 see this site:
http://www.tiptonium.com/videogames/reviews/other/XRGB2.htm

tiptonium is a member here at the forum

werejag · May 8, 2005

the sony chip are suspose to bring up the hsysnc and vsysnc arent they?

when it comes down to it if i need another chip to get vga i shall.

ps thanks the discusion has helped me alot.

Robert · May 8, 2005

A little off topic but....

After seeing the neo on various new gen monitors, I doubt about the usefulness of such mods. a low res console like the neo on a VGA monitor will certainly look like shit no??

Just my two cents.

werejag · May 8, 2005

maybe it will look like shit. then all ive done was improve the video past the point of usefulness and i would have learned the upper limits of neo geo video.

dogtoy · May 9, 2005

All you have to do to see the upper limit of Neo-Geo video is to hook it up to a top of the line RGB arcade monitor.

VGA output from the RGB output can never surpass the original RGB output, this is a fact due to the loss of signal quality that will occur with the extra circuits required to convert the signal. The very best you could hope for when converting RGB to VGA like this is for the VGA output to look 90-99% as good as the original RGB signal. The only way to fix it is to start with the digital signal on the motherboard.

If you really want to see the best video a neo could output, you could cut out all of SNK's D/A convertor section (the part that makes the digital video signal into analog RGB). You could then replace this with your own DAC to output s-video, vga, hi-res component, progressive HD compatible component. If you really want the best why try to make a better signal from a mediocre one, when you can generate whatever you want right from the best video source available on the board...the digital video signals.

This will require huge ammounts of rewiring, a huge ammount of technical finesse/skill, and probably a good chunk of cash.

Cheers,
-DT

Reznor007 · May 9, 2005

werejag said:
maybe it will look like shit. then all ive done was improve the video past the point of usefulness and i would have learned the upper limits of neo geo video.

The upper limit of Neogeo video is 320x224. Using a high quality RGB arcade monitor is the absolute best it will look. Upscaling it to VGA or HD will merely bring out how low res NeoGeo is.

dogtoy · May 9, 2005

Reznor007 said:
The upper limit of Neogeo video is 320x224. Using a high quality RGB arcade monitor is the absolute best it will look. Upscaling it to VGA or HD will merely bring out how low res NeoGeo is.

Thank you! Exactly the point I was trying to make in a much more succinct form!

Cheers again!
-DT

werejag · May 9, 2005

Reznor007 said:
The upper limit of Neogeo video is 320x224. Using a high quality RGB arcade monitor is the absolute best it will look. Upscaling it to VGA or HD will merely bring out how low res NeoGeo is.

so what your saying it the products like X-RGB2 are indeed over priced becuase Neogeo video is 320x224 and calling such low quality video monitors, high quality RGB arcade monitoris a luagh?

so basicly what i gather is i will not gain any benefits from a over priced upscan convertor and making one will give me the same benefits. for 1/10th of a price

acem77 · May 9, 2005

i have the neobitz board now for my neo geo, genesis, turbo duo, super nova.
i had to rig some stuff to get all to work but the neogeo aes.
i made a rgb amp for the duo was too dark with out it.
had to limit the rgb values for the super nova and genesis, then i had to to some other crazy stuff for my genesis. at that point i needed to make a circuit for that stuff.

then i got my turbo duo to work perfectly with my vga input on my dlp.
i tried this a while back but the pic would not stay for all games.
the rgb amp fixed that. the video looks so nice with the vga input.

i could not get the genesis, neogeo or supernova to work with the vga port solid enough.

i won a XRGB-2 Plus for $100 on ebay. i am hoping this will let all my systems work with the vga input.

ill let you know what i think after some testing

i hate when people say the video looks like crap.....
i love the look of it.
a simple test is to load up the romz on an emulator and see what you think when no filters are on.
this is what a clear video feed will make the real games look like on a monitor or hd tv.
the video is perfect. maybe too perfect for some peoples eyes.
if you like the super sharp look of an emulator on a pc monitor you will love the look of the real neo on a monitor or hd tv.
if dont like the look then dont spend the money.

but i am pro for sharp no scan line video for any system.

video chip help!!

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