NeoVGA: Lagless, pixel-perfect line doubler for Neo-Geo MVS and AES

Yodd

Iori's Flame
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Feb 7, 2002
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Would be nice to see this project be able to be adapted to a couple other platforms, like some of the retro computers. I imagine the Atari ST guys would go apeshit over a high quality VGA output option for low res stuff that maintained the ST's wacky video timing.
 

McColbo

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I know you are probably inundated with messages about this...but any idea of ballpark size of the board? I'm designing my mvs console enclosure and would like to make sure I have room. I won't hold you to it, just curious if you knew yet.
 

mikejmoffitt

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The board being manufactured now is 2.61x2.01 inches (66.32x51.05 mm). There are four mounting holes on the side for screws, but of course you must have something to screw in to. It is pretty small and light, so for a lack of anything better a few dabs of hot glue on the corners will hold it in place well, as a last resort. It would be best to leave at least a half inch of clearance above the board.
 

lions3

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Too bad you can't turn this into a VGA version of XRGB. Would love it if this could be in a small enclosure with a cable port you connect to your MVS or CPS2 (which have all the wire connections done inside). I guess that's wishful thinking between the ton of board connections and needing to flash the board for each system.
 

mikejmoffitt

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For that the OSSC project is available. It would be nice, but the design is completely different and you would shed the advantages of a digital capture system. I'm going to have to make an FAQ because every day there's a post about making a universal scaler like the XRGB, and while I would appreciate such a project I have no plans of ever making one.
 

DrHuxtable

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I'm fine with and prefer the current design. It's like dedicated summer and winter tires vs all-seasons. Can't wait!
 

Chael

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Dec 27, 2014
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A FAQ would be nice for neophytes like me.
For example I'd like to understand the differences and how worse would the image linedoubled with the OSSC and a hdmi>vga adapter be compared to the NeoVGA (both on a vga crt).
 

GTRetro87

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Aug 20, 2014
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I have a good question. Currently, I'm using the JROK RGB encoder right off the Jamma edge. Is it possible to install the NeoVGA and still keep the JROK encoder running off the jamma edge?

If so (I hope), then I can use the CMVS on multiple platforms (until the day comes that I have a TV set that accepts VGA/HDMI only)
 

mikejmoffitt

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Yes, the original outputs including the ones on the JAMMA edge are untouched, and won't be disabled or darkened at all.
 

mikejmoffitt

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I've built the last hand-made one I'm willing to make while I'm waiting for the production one to arrive. Here's a better shot of what a (messy) install can look like in an MV-1C:

9wL8TVb.jpg


The huge blobs at the bottom are because I ran out of resistors and couldn't install my pull-ups on the unused inputs, so I'm tying them to ground. That definitely isn't needed in the production unit!

Right now the hold-up is trying to deal with one final hiccup, as it looks like we may have found one monitor that isn't compatible; a little more experimentation is needed. I can't guarantee that it'll work on every monitor or TV, as the Neo-Geo's timings are a little odd (59.2Hz refresh, for example) which is something I think a lot of users are already somewhat familiar with regarding RGB/Component options.
 

nam9

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Oct 24, 2014
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151
What controls the refresh rate in the Neo?
Thought there was some talk about replacing the Neos' clock with a 60Hz signal to produce a perfect refresh rate but essentially overclocking the Neo that lttle bit...

My Sony TV is very picky about VGA refresh rate (not that its a great set) so definitely an issue for some.
 

aha2940

AH, A, COLUMBIAN!,
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The more I look at that install pic, the more I realize I will not be able to install this all by myself.Sigh. I guess I'll have to pay someone to install it...
 

Hellfromabove

Dodgeball Yakuza
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Jun 10, 2006
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635
Man, this thing is looking awesome. The amount of wires I will need to solder doesn't bother me in the slightest. Not everything can be easy :).
 

RockstarRunner

Wind Jammin' All Night",
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Mar 25, 2004
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645
What controls the refresh rate in the Neo?
Thought there was some talk about replacing the Neos' clock with a 60Hz signal to produce a perfect refresh rate but essentially overclocking the Neo that lttle bit...

My Sony TV is very picky about VGA refresh rate (not that its a great set) so definitely an issue for some.

This! I've been following this project since the first post, and it's simply awesome, great job! But i'm in the club of having a very picky display, and have been wondering the same thing, could anything be done about this? I think I read in the HDMI mod that the FPGA is altering the display clock to bring it in line, so it might be possible.
 

mikejmoffitt

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The texas flood has delayed the manufacturer a little bit, but I do not think it should be a huge delay. I expect my manufactured PCB will arrive shortly. I can finish up my documentation in this time.

I am thinking about creating an order interest + FAQ thread for this, since this development thread is quite long and I would not expect anybody to sift through it for answers.

This! I've been following this project since the first post, and it's simply awesome, great job! But i'm in the club of having a very picky display, and have been wondering the same thing, could anything be done about this? I think I read in the HDMI mod that the FPGA is altering the display clock to bring it in line, so it might be possible.

I really don't want to do this for a few reasons - first and foremost, I've worked on this project a lot and I'm kind of tired of the development and want to move more into deployment. It has also been quite expensive so any return on investment is a good thing. That said, I have no interest in releasing a sub-par product so that is why compatibility testing remains an ongoing endeavor. So far exactly one monitor has been found that is rejecting my 480p signal. I haven't drawn up a list, but I've tested dozens of monitors, so I am hoping this is a fluke. We haven't even exchanged hardware yet, so it is possible there is actually a problem with that specific hand-built board.

The second reason is that while slightly overclocking (and selectively double clocking or giving an uneven clock pulse width) "seems" okay according to notes, actual testing is restricted to one game (SvC Chaos). I would have to test every Neo-Geo game to be confident that this slight but serious modification to the architecture isn't going to mess up some games but not others. I would feel uncomfortable releasing a product for which there are so many unknown edge cases. I am more confident saying "This works on every monitor I can test, and is very likely to be fine with your VGA monitor (of which many exist and are cheaply available)" rather than saying "This works on all monitors, and all games probably still play okay".
 
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Xian Xi

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MVS and 1st gen AES with the 1st gen chipset all run at 59.18hz, the newer AES consoles run at 61.18hz iirc. So if you overclock it, it will lock it to only MVS and the 1st gen AES.
 

RockstarRunner

Wind Jammin' All Night",
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That's some good points, makes sense that it would be out of scope to deal with. Once again, everything you've shown looks great, I hope you have some real success selling these, you'd deserve it.
 

nam9

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MVS and 1st gen AES with the 1st gen chipset all run at 59.18hz, the newer AES consoles run at 61.18hz iirc. So if you overclock it, it will lock it to only MVS and the 1st gen AES.

Overclocking was just a byproduct if I understand correctly. In the event of newer AES consoles, the result would be a slight underclocking (to the substituted 60Hz signal).
If Neo games run on both 1st gen systems (59.18hz) and newer systems (60.18Hz) without issues, I would doubt that 60.00Hz should have much impact... but then again you wouldn't know that without extensive testing...
 

DrHuxtable

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The more I look at that install pic, the more I realize I will not be able to install this all by myself.Sigh. I guess I'll have to pay someone to install it...

Nah. Just take it one wire at a time. Anyone without severely shaking hands can solder.
 

mikejmoffitt

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Overclocking was just a byproduct if I understand correctly. In the event of newer AES consoles, the result would be a slight underclocking (to the substituted 60Hz signal).
If Neo games run on both 1st gen systems (59.18hz) and newer systems (60.18Hz) without issues, I would doubt that 60.00Hz should have much impact... but then again you wouldn't know that without extensive testing...
It's not just that, though. If it was just making it run at 60Hz, that'd be fine, as that's just evenly scaling everything. The described oveclock has it running at one speed, and occasionally doubling clocks to make up the missing time. In other words, the clock speed is slightly variable. It's probably fine, but if that has potential issues I don't want to find out later down the road.
 

mikejmoffitt

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The PCB arrives tomorrow. I'll take some pictures of what the real manufactured board looks like!
 
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