4-player JVS based games?

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4-player JVS based games?

Post by UrQuan3 »

I know I'm the one that keeps asking annoying questions, but here's another annoying question. I finally got around to having the PCB for the 4-player version of my DB-15 to JVS adapter fabricated. Everything tests out great on my one and only 4-player JVS game, Powerstone 2. I am now wondering if there are any other single board 4-player games that use JVS so I can do more testing. The only other one I know of for certain is WWF Royal Rumble, but honestly, I really don't care about that one. I haven't found mention of much else online.

- Powerstone 2
- WWF Royal Rumble
- Pengo on RingEdge 2? (not sure it existed)
- Dariusburst: Another Chronicle? (high odds it's Fast I/O. I have no idea what the wiring looks like)
- TMNT by Raw Thrills?
- Minecraft Dungeons by Raw Thrills?

Any 4-player 1-board JVS arcade games on any SEGA, Taito, Namco, etc board that anyone can think of? Are any of the above actually Fast I/O instead of JVS?
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Re: 4-player JVS based games?

Post by sven666 »

Outtrigger and spawn on naomi support 4 player i think? Not sure of the setup tho.
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Re: 4-player JVS based games?

Post by nem »

You have to link motherboards for 4-player in those two games. Same with Heavy Metal.

Dariusburst is Fast IO.

Pengo is actually a good question, I have been wondering about that myself. I think it will work, but I haven't tried it.

Anyway, for Naomi / Naomi 2 there's

Beach Spikers
Power Stone 2
Ring Out 4x4 (you need analog controls for this)
Virtua Athlete
WWF Royal Rumble

and on the exA

Cosmic Digger
Lightning Knights
Nippon Marathon Turbo
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Re: 4-player JVS based games?

Post by FrancoB »

Virtua Tennis 4 on Ringedge.
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Re: 4-player JVS based games?

Post by UrQuan3 »

Sure enough the exA has several 4-player games. They even have their own 4-player "cabinet". Really more of a dresser, but that's the right call. Makes me want to buy one just to test, but !@#! new hardware is expensive.

@nem Thanks for the list. Beach Spikers could be fun. Of course Ring Out 4x4 is a different animal. I bet I could make it work, though I'd be making up my own pinout for analog through DB-15. That one would be an adventure.

@FrancoB Thanks! Namco and Capcom had been making quite a few 4-player games up through the start of the Naomi, then *poof*. I figured there would have to be something in the 20 year gap between then and now.

Come to think of it, I suppose *testing* using a NET-DIMM is valid. Up to now, I've only listed as tested titles I actually own.
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Re: 4-player JVS based games?

Post by Shou »

When you say 1 board, I assume you mean 4 players on a single JVS node?
Back in the day, only Capcom implemented titles in that manner since their IO board is the only one to support that from the era.

Multi player games on 2 or more JVS nodes was abandoned early on due to the inherent lag with this kind of setup.
The JVS link is like a long daisy chain and the more "jumps" the signal has to do will increase lag and the potential for interference in communications.
If there is any interference, players will see it as lag or lost inputs depending upon how the PCB deals with it.

The 1st generation of JVS IO boards, developer SDKs and later cabinets like the Noir are poorly designed to handle even a back to back VS setup.
The Noir linked has 9 points to jump through which accounts for why namco dropped JVS linking after Tekken 6 for LAN.
Pengo on APM2 has terrible lag when linked up. They abandoned JVS linking on the APM3 version and connect via LAN instead.

exA-Arcadia games can support both 2 nodes for 4 players and 1 node for 4 players in the most recent updates.

Available Now:
Cosmic Digger 3671
Lightning Knights
Nippon Marathon Turbo

Announced Upcoming Titles:
Jitsu Squad
P-47 Aces Mk. II
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Re: 4-player JVS based games?

Post by UrQuan3 »

@Shou Man, there is some good info in that post. I am still trying to unpack it all.

Earlier this year, I was asking how Powerstone 2 was hooked up in Japan, and I found out that it was done by tying two cabinets together and mirroring the screens. I came to the conclusion that 4-player cabs just weren't a thing in Japan, though they were among the most popular in the U.S. To me that suggests that Capcom's I/O board supported chaining for Japan and 4-in-1 for the US market. Since 2000-2001 is when the arcade died in the U.S., I can see why that capability was dropped.

9 nodes. Wow.

There is little inherent lag in the multi-node standard itself. RS-485 is good to over 1000 meters at those speeds. There are no hops. The data and ground lines are tied together for the whole run with nodes tapping the line along the way. Only the sense line is point to point, and it's only used at startup. There are no collisions as nodes only send when the master asks them to. However, with each node having two plugs and two data connectors per plug, a 9 node setup would have 2*(2*7)+2*(2) = 32 places where a speck of rust or dust could cause the whole thing to fail. There's also the possibility that any of the nodes might not have a properly high impedance when tapping the line, causing the signal to become unusably weak. I don't know this, but there is also the possibility that the master is somewhat, unintelligent, and polls all nodes at the same frequency. We don't need millisecond accuracy for if a card is inserted in the reader.

Let's see, mathing it, the entire request/response for a single player I/O node would be 8 bytes. JVS bitrate of 115200, so: 1/(115200/8)*8 = 0.6ms. Polling one 4 player node would be 14 bytes, only 2 extra bytes per player. 1ms. Four 1 player nodes would 32 bytes. Still only 2.4ms. Polling all 9 nodes the the noir you describe would be 5ms at theoretical best. I bet some nodes have larger frames and not all of them would reply instantly, so it would only get worse. I agree, sounds like a disaster.

Thanks for the info.
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Re: 4-player JVS based games?

Post by Shou »

It isn’t 9 JVS nodes on 2 linked Noirs. It 9 jumps to go from the PCB to IO board 1 then IO board 2 and back.

Without a picture, it may be difficult to grasp but see below for the route the signal has to go through to communicate 1 JVS input to both cabinets.

exA > Noir IO sub board 1 > Noir IO board 1 > Noir IO sub board 1 > Noir IO sub board 2 > Noir IO board 2 > Noir IO sub board 2 > Noir IO sub board 1 > Noir IO board 1 > Noir IO sub board 1 > exA

The potential for signal degradation and simply input loss is high. When there is packet loss, then another packet is sent which the end player sees as lag or missed commands.

1st gen JVS IO boards like the Sega JAMMA cannot process commands as quickly as you have described. Yes, you can send a command faster but you will deadlock the IO board.

Making a system that works with all of these manufacturer anomalies is challenging.
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Re: 4-player JVS based games?

Post by UrQuan3 »

JVS standard
http://superusr.free.fr/arcade/JVS/JVST_VER3.pdf

Page 12. There are no hops. See how ground and both data lines are tied straight through and each node taps the line. Classic rs485. All nodes see all traffic at the same time. The node that the message is addressed to is the one that replies.

Of course, all those taps cause loss. Every cable connector causes loss. Like you say, if the signal is weak, messages will get corrupted randomly. Since JVS does not include error correction, a failed checksum results in the message being ignored and the mainboard has to send a new request, possibly having to wait for a timeout first. Not optimal. I wish I could play with that setup and try to find what's taking so long.

Oh look, it says the mainboard only sends out requests about 60 times per second. That's 16.7ms per request by definition. I was wrong there. I guess the JVS spends most of its time idle. A single I/O probably replies much faster, but we can't talk to the second board till 17ms have gone by. How many I/O boards are there in that noir setup? If I count 6, then polling all of them would take 1/60*6 = 100ms. Enough to annoy many people. If most of the time it polls only the I/O (1/60*2 = 33ms max), but sometimes polls all 6, the lag would be variable, which is even worse.

Ok, now I think I see the problem.

Manufacturer anomalies: I can only imagine. The ability to optionally include multiple requests to a single node in a single message could confuse anyone.

Thank you for your patience.
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Re: 4-player JVS based games?

Post by Eddierang »

Correct me if I’m wrong Shou, but I thought Tekken Tag 2 also used JVS for linking as well.
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Re: 4-player JVS based games?

Post by Shou »

Eddierang wrote: December 16th, 2021, 5:38 am Correct me if I’m wrong Shou, but I thought Tekken Tag 2 also used JVS for linking as well.
I believe overseas versions of TTT2 and T7 can use JVS linking but in Japan, it is LAN only as the level of lag wouldn't be acceptable for customers.
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Re: 4-player JVS based games?

Post by trap15 »

Despite the rs485 being common to all nodes, there is nontrivial extra latency in linking compared to single node 4p.

The main board must wait for the first node command to come back before sending the next one, the IO boards do not respond to a finished transmission instantly (the time probably slightly scales to input size, but the overhead here is mostly static regardless of the size and amount of data requested), and there are a fairly decent number of extra bytes to transmit for each packet that must be done twice when on two nodes. All this together adds a surprisingly large amount of extra poll time even ignoring issues like signal degradation that will require periodic re-submission.

Despite the quality of rs485, the cabling being USB means often times cabinets are using very low quality cheap cables that have been in service for nearly 2 decades and are starting to wear out badly, so signal degradation is not actually uncommon here.
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