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 Post subject: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Fri Jan 08, 2021 4:59 am 


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Joined: 11 Jul 2018
Posts: 74
Location: Alberta
Hi All,

Thought I'd share one of my latest designs. Actually I've sat on this one for some time but finally have a little more bandwidth to pump out units for sale.... 8)

As the title implies, it's a kit to make your own Neo Geo console from original MVS boards (often referred to as 'CMVS'). This kit will work with Neo Geo MVS boards with model number MV1C.

The differentiator on this one being that it supports Super Nintendo controllers in place of Neo Geo controllers, making it much more affordable to get into Neo Geo. The board has two ATTINY-2313 ICs that turn the serial data from a SNES controller into parallel data, without any lag! I wrote the code in a combination of BASIC and Assembly and have open sourced it on GitHub.

This board outputs a 15Khz RGB signal, exactly as produced by the Jamma edge connector, with Csync acting as Hsync; thus you will have to utilize a proper monitor, or video upscaler, that can support this signal as it is a low horizontal refresh frequency not commonly supported by modern equipment.

There is a jumper to route Csync through a 470 ohm resistor if required (in cases of non TTL equipment). Also on the latest design I've added circuitry on the RGB lines if you'd like to install any resistors on the RGB lines to limit current, or even form a voltage divider to knock down voltage; for exotic/specific cases. (I really wanted to make sure all display/monitor scenarios were covered!).

Units come with a 3amp Triad Magnetics power supply, and have been tested working with 161-in-1 game carts! :D

You can purchase from my Tindie Store at the link below:
https://www.tindie.com/products/chipnet ... herboards/

Obligatory photos:
Image

Image

Thanks y'all!
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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Sat Jan 09, 2021 7:27 pm 


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Joined: 26 Jan 2005
Posts: 183
Location: UK
Hey! This looks great and landed at just the right time for me. Just ordered the assembled kit :)


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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Mon Jan 11, 2021 4:02 am 


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Joined: 11 Jul 2018
Posts: 74
Location: Alberta
Awesome thanks so much for the support!

Sent from my CLT-L04 using Tapatalk
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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Mon Jan 11, 2021 5:27 am 



Joined: 04 Apr 2014
Posts: 842
Nice design. I think this will be a popular item.


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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Tue Jan 12, 2021 10:40 am 



Joined: 17 Mar 2018
Posts: 137
Location: Germany
This looks really cool!
About the VGA output: does Pin 9 of the VGA port provide 5V DC? That way it would be possible to build a SCART cable with attenuating resistors in the RGB lines.


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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Wed Jan 13, 2021 10:41 pm 


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Joined: 11 Jul 2018
Posts: 74
Location: Alberta
SuperSpongo wrote:
This looks really cool!
About the VGA output: does Pin 9 of the VGA port provide 5V DC? That way it would be possible to build a SCART cable with attenuating resistors in the RGB lines.


I'll admit, I didn't pump 5V on Pin 9; I even grounded it instead of leaving it floating. Really if the demand was there, it's pretty easy to add the extra trace in the next PCB run come a month or so.

Thanks for the kind comments all!
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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Thu Jan 14, 2021 7:44 am 



Joined: 17 Mar 2018
Posts: 137
Location: Germany
Yeah, I was afraid of that :mrgreen: This being a kit would have made it easy to add one wire to the pin. If you ever end up doing a redesign, maybe you could indeed leave the pin floating :)


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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Thu Jan 14, 2021 2:43 pm 


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Joined: 05 Mar 2018
Posts: 1388
SuperSpongo wrote:
Yeah, I was afraid of that :mrgreen: This being a kit would have made it easy to add one wire to the pin. If you ever end up doing a redesign, maybe you could indeed leave the pin floating :)

Yes - please float pin 9 on any source device anyone builds vs grounding it. Early VGA cards as a general rule floated it, before DDC support came around.


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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Fri Jan 15, 2021 7:13 pm 


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Joined: 26 Jan 2005
Posts: 183
Location: UK
SuperSpongo wrote:
This looks really cool!
About the VGA output: does Pin 9 of the VGA port provide 5V DC? That way it would be possible to build a SCART cable with attenuating resistors in the RGB lines.

Hey, can you educate me as to why that would be needed? Is that to enable RGB on a Consumer TV without needing to go through something like a Syncblaster?


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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Sat Jan 16, 2021 2:40 am 


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Joined: 11 Jul 2018
Posts: 74
Location: Alberta
Really to power additional video devices without having to use extra power adapters. (For example a syncstrike can be powered over scart or via external psu.) It's just an extra way to pass on power to other devices, that's of course if the device on the receiving end is wired to accept power on pin 9 as well. It never really hurts to pass on power; I had just left it absent mostly due to space constraints on the bezel of this pcb design; also the neo geo with a 161 cart already draws quite a few amps and didn't want the bit of headroom left to be eaten up from other devices through vga power - albeit someone could just use a bigger psu.

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 Post subject: Re: Yet another Neo Geo MVS console Kit (CMVS)
PostPosted: Tue Jan 19, 2021 12:11 pm 



Joined: 17 Mar 2018
Posts: 137
Location: Germany
JigsawMan wrote:
Is that to enable RGB on a Consumer TV


Yes, most TVs in Europe need a blanking signal on Pin 16 to switch to RGB.

Wikipedia wrote:
0..0,4 V– (low = FBAS), 1..3 V– (high = RGB) @ Z = 75 Ohm


RGB cables usually come with a 180 Ohm resistor to create a voltage divider with the TV's internal 75 Ohm resistor.


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