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UrQuan3

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(edited 7-21-2021: add Taito Type X)

I think this post belongs here?

I had been working on an adapter to connect DB-15/supergun style fightsticks to the SEGA Naomi. After wiring the first DB-15 to the breadboard, I looked at the rats nest and decided to design a PCB instead. So, here it is:

https://github.com/UrQuan3/DB-15_to_JVS/blob/master/photos/20201129_161414.jpg
https://github.com/UrQuan3/DB-15_to_JVS/blob/master/photos/20201129_161351.jpg

I started with ‘charcole’s JVS code for arduino and adapted it to support two players with 6 buttons, a start, and a coin each. The DB-15 pinout is SNK standard, but with pin 2 and 10 used for button 6 and 5. The adapter pulls 5v from one USB cable and uses a second USB cable for JVS. At this point, everything seems to be working.

The adapter has tested good in 2-player mode with:

SEGA NAOMI:
- Dead or Alive 2
- Moero, Justice Gakuen
- Marvel vs Capcom 2
- Melty Blood: Actress Again
- Radrgy Noa
- Power Stone 2 (2-player mode)

Taito Type X
- Goketsuji Ichizoku Matsuri Senzo Kuyou (service button implemented, but no trace on PCB)

From the pictures, you can see my testing setup is no good for testing lag. There is real possibility that it may work with other JVS systems, but I have not been able to find any to test with.

I have a question though. Would anyone else find this useful? I could sell complete boards, or sell the bare PCB with a parts list. I should probably design a case. I’ve already posted the source code.
 
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randomdoohickey

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I can see some demand for this, but not much given the relative lack of modern DB15 sticks.

What I do see getting a lot of demand, however, would be a direct USB-to-JVS dongle/board. Plug in your modern gamepad/fightstick into the dongle and the other end into JVS. I'd imagine @Raph_friend's USB2DB15 has most of the code you'd need on the input side.
 

Raph_friend

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I can see some demand for this, but not much given the relative lack of modern DB15 sticks.

What I do see getting a lot of demand, however, would be a direct USB-to-JVS dongle/board. Plug in your modern gamepad/fightstick into the dongle and the other end into JVS. I'd imagine @Raph_friend's USB2DB15 has most of the code you'd need on the input side.
Honestly I don't know how JVS works.
 

Dreamstate

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Unless I am missing something, this should work with either the USB2DB15 from Raph_friend or the Undamned USBtoDB15. While an extra board, it should give us a way to use the same stuff we connect to a Jamma Supergun to instead connect directly to a JVS system. If nothing else, it is a great hopping off point to look at other variations. Depending on the price and if it does handle lag, seems very interesting.
 

UrQuan3

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Oh, thank you for the replies.

The DB15 was the result of my building my own arcade sticks (https://www.deviantart.com/urquan3/art/2020-08-27-Arcade-Sticks-003-853462741). It's a simple active-low per button design instead of something super complex like USB. I also designed a DB15toUSB adapter to use the same sticks on a PC. (That direction way, *WAY* easier than what @Raph_friend's project does.)

I do think the USB2DB15 adapter would just work. I like the idea. If there was a way to buy one to test I would. Maybe I should just get over it and build one, I'm just really not looking forward to hand wiring another set of DB15s. You should have seen the mess of wires on the breadboard for this project.

I am not sure I understand tonyt76's question. I don't have a MiSTer (yet), but wouldn't you just connect your USB controllers to the MiSTer? If you have a DB15 controller, I do have an adapter, or you can build your own by setting a teensy in joystick mode.

I did dig through the USB2DB15 Adapter code back in December. It's using C++ and class inheritance, which is nice to code, but carries quite a bit of overhead. I don't know if there is a microcontroller yet that could run 2-4 copies of USB2DB15 (2-4 player) and the JVS code all at the same time. I could be wrong. Still, the separate adapters would be expensive, but reliable.

I'm trying to get the price well under $100, but recent changes to the US tax code says that you cannot deduct parts, shipping, listing, or transaction fees as an individual, you must be an incorporated business. Walking the US business tax code is going to take some time.
 

jassin000

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Sorry I meant JVS arcade controls to MiSTer
Hopefully this will be fully supported by a firmware update for the JVSPAC.
Ke8eXPA.jpg

I don't have a Mister, so I can't explain what the current issues are... Only that it has them.
 

UrQuan3

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I have to admit, the existence of the JVSPAC confuses me. It would seem like removing the JVS I/O board entirely and replacing it with some form of i-PAC with City or Vewlix connectors would be the faster/lower latency route. This would not be that difficult to build. Hardest part would be finding the connectors.
 

jassin000

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It would seem like removing the JVS I/O board entirely and replacing it with some form of i-PAC with City or Vewlix connectors would be the faster/lower latency route.
According to @invzim the polling of the JVS is happening so fast lag is not a factor.
Infact what you are describing is exactly how Taito officially handles JAMMA inside a Vewlix (ie the kit contains a new direct wire bypass harness, part #4 below).
wbYsVna.jpg


The problem with this method is clear however, to then use a JVS based system again you must now reconnect/shuffle around a pile of harnesses.
The most versatile setup (ie easiest to get working/switching with everything JAMMA/JVS/Fast) is to have the cab wired for JVS, use a Jammafier to adapt JAMMA into JVS and finally use the official Taito FastIO JAMMA adapter in conjunction with all that.
ubIkxJE.jpg


At this point the JVSPAC is really only useful for putting PCs inside a JVS based cab...
But the idea is with the right firmware the device could self-identify as anything you wanted.
A generic/compliant HID device for Mister? Switch Pro gamepad? Why not?
 
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UrQuan3

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Hmm, cool. Give me a few days to think through that. I think I'm following your setup though. If there existed a direct Fast to JVS adapter, your setup would be easier still? Having never seen a JVS or FastIO setup in person, I don't want to use up your time explaining things to me. Thank you.

On a different note, maybe I should track down a Jammafier and see if my JVS adapter works with it. That would be really handy.....wait, that *IS* a supergun, isn't it?
 

Raph_friend

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I do think the USB2DB15 adapter would just work. I like the idea. If there was a way to buy one to test I would. Maybe I should just get over it and build one, I'm just really not looking forward to hand wiring another set of DB15s. You should have seen the mess of wires on the breadboard for this project.



I did dig through the USB2DB15 Adapter code back in December. It's using C++ and class inheritance, which is nice to code, but carries quite a bit of overhead. I don't know if there is a microcontroller yet that could run 2-4 copies of USB2DB15 (2-4 player) and the JVS code all at the same time. I could be wrong. Still, the separate adapters would be expensive, but reliable.

The last batch for USB2DB15 assembled pcbs for donation reward was 3 times bigger than usual, so atm i don't have any room for pre-order, maybe February.
But yes, you can try build it yourself, and join us on Discord anytime.
 

drfunk2k

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Undamned USB2DB15 works on Axun JAMMA/JVS supergun
 

UrQuan3

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Updated to post to include the Taito Type X and the one game I have access to, "Goketsuji Ichizoku Matsuri Senzo Kuyou". I had to implement JVS command 30: CMD_WRITECOINSUBTRACT. Seems the game thinks about coins and credits differently from everything I have on NAOMI. On NAOMI, the game looks at the current coin count, the previous coin count, and adds the delta in credits. On the Type X, it seems to use the current coin count as the current number of credits and subtracts X coins when you use a credit. If that isn't subtracted, your number of credits never goes down. I'm not sure if that was for all Type X games, just games by ATLUS, or just Goketsuji Ichizoku Matsuri Senzo Kuyou. I have a sample size of one.

I also had to implement the service button as the Type X does not have a service button on the main board. I updated the PCB design, but it could be years before I run out of the current design, so I'll probably solder a button directly to the controller if needed.
 
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