Linking 2 Dreamcast to make a 8 players homebrew game

[patbier]

Hello,

I wonder if there is a way to link two Dreamcast, in order to make a 8 players homebrew game.

An expensive way is the BBA, but as it is very rare and expensive, it seems impossible to afford.
The link cable exists but I think it's not implemented in KOS.

Would it be possible to link the Dreamcast with the modems ?

[GyroVorbis]

I think writing the driver for the VS link cable would probably be infinitely easier than networking two Dreamcasts with modems like that.

[|darc|]

I think writing the driver for the VS link cable would probably be infinitely easier than networking two Dreamcasts with modems like that.

I was about to say the same thing.

The only problem is that the link cable itself is pretty hard to find as well, although it would likely be much easier to produce more of them.

[BlueCrab]

Either should (modem or serial cable) technically work, but you'd probably have loads of connection problems between two modems. That, and your speed would be more limited over modems (effectively to a max of 33.6kbps).

[patbier]

Thanks for all your answers !

To be more precise, I'd like to link two Dreamcast :
- the first Dreamcast will display the game, and use the 4 controllers for player 1,2,3 and 4
- the second Dreamcast will be only used for its 4 controllers for player 5,6,7 and 8

Do you think that it's possible to make a "homemade" vs link cable ?

[Christuserloeser]

Maybe you could use the PS1 or Saturn multiplayer adapters via Total Control ?

http://www.play-asia.com/paOS-13-71-h5-49-de-70-47.html

http://www.play-asia.com/paOS-13-71-h5-49-de-70-46.html


You could use the SD card adapter to update / patch the game later for modem or link cable support. (Sturmwind allows this too).

In a later reprint or the game this patch could be built in by default.

[patbier]

The Total Control idea would be great and easy, but I don't think KOS will allow to use it.

For the SD card options, it's not simple.
As BlueCrab said, there could be a problem with FAT patent.

[BlueCrab]

The Total Control idea would be great and easy, but I don't think KOS will allow to use it.

Well, the only way to find out is to try. I honestly have no idea whether or not it would work, to tell the truth.

For the SD card options, it's not simple.
As BlueCrab said, there could be a problem with FAT patent.

KOS 2.0.0 does support the SD card adapter with Ext2 as a filesystem on the cards, so you could always use that (and there shouldn't be any worries about patents there).

[Christuserloeser]

If anyone of you (BlueCrab or patbier) needs a free Total Control adapter PM me, I got a few spares lying around collecting dust.

[GyroVorbis]

Actually, I think I have all of the hardware required to try this... I am going to be very shocked if it works, though...

[Christuserloeser]

I think there needs to be some kind of driver for this to work, maybe some PS1/PS2 emulator hints at the required code ?

Maybe the driver has to map some buttons to a specific controller in order for this to work - i.e. register only analog stick and button 1+2 on PS1 controller 1, but d-pad and button 3+4 on controller 2 ? This would already allow up to five players at once.

Might be worth a look to see if the Saturn multi tab is easier to emulate than the PS1 multi tap.

[GyroVorbis]

Oh, I am almost positive this won't work without you writing your own driver to do it, but that's not such a big deal.

maybe some PS1/PS2 emulator hints at the required code ?

That wouldn't really help you with the driver on the Dreamcast, but it would help you figure out how the PSOne accessed additional controllers hanging off of a single port.

You need to find out how the PSOne's equivalent of the DC's Maple Bus works, find out through what messages/registers the PSOne was able to request input from other devices hanging off of a single port, then figure out if the converter is even handling or forwarding those additional messages/signals. There are a lot of factors coming into play here...

But yeah, then there's also the chance that the Saturn scenario is more feasible than the PSOne and vice versa. It'll definitely take some tinkering and experimenting.

edit: I'm no electrical engineer, but I wonder how complex the circuitry inside of those things is. I bet someone here could roll their own box that could actually handle this.

[GyroVorbis]

So I own this thing (which supports PS1 and Saturn controllers and PS/2 keyboards:


and I just purchased a PS1 multitap... If I get a chance, I might try to play around with this idea.

[patbier]

Great ! Thanks !

[PH3NOM]

Sort of off topic, but since we are already discussing potential uses of the Maple bus...

I was wondering why we cant build a SD adapter than can run from a controller port instead of the serial port ( my understanding is that the controller ports operate at 2Mbps )
But I am not an electrical engineer as Gyro also mentioned, just an idea...
After all, that is the bus Sega decided to use to interface with external memory...

[|darc|]

I don't see any reason why that wouldn't be possible. Most likely the serial port was chosen because it's the easiest to interface with. After all, the SD card slot is only a few components and is very easy to build, whereas doing it with the maple bus would require a lot more work and likely programming some sort of microcontroller.

If you really wanted it to be the fastest, though, interfacing it with the G2 bus would be the best option, though, wouldn't it? It would pretty much have to be internally done, though, but it would also support running the SD card slot and ethernet/modem at the same time since you can have multiple devices connected to the bus.

[BlueCrab]

To work with the maple bus, you pretty much have to speak the same wire protocol as some other device. While it would be theoretically possible to make a SD card look like a VMU if you were to do so, it would, as |darc| states, require some sort of microcontroller in the center to do the work.

[patbier]

From reading this website : http://www.segatech.com/technical/dcblock/index.html
It seems that :
"The port coming off of the SH-4 is the rear serial port, that has the same performance characteristics as the controller ports, which is about 2 Mbits/s, or 250 KBytes/s. This port can be used for networking two DC's together, or attaching external devices like a keyboard, etc."

So I have 2 questions :

1) With the KOS sd card adapter in ext2, do we achieve the 2 Mbits/s ?

2) As a sd card adaptater in the serial port, could we imagine building a "multi tap" adaptater in the serial port ?

[Quzar]

In my mind the easiest solution, if you're ok with using genesis-style controllers, would be to hack up a keyboard, and attach a bunch of controllers to it. You could probably fit a full 8 controller ports onto a single keyboard. With so many, it would run into issues of too many simultaneous presses, but I don't think that would be very bad. Maybe 4 would work better.