Dreamcast BBA Stupidity

[Blaine]

As I oft do, I stand before as a man with a question - who's answer, I'm pretty sure I already know. Because if what I asked were possible, it surely would have been done long ago.

Thank you for reading this.

Does anyone have an information on the make-up of the Dreamcast's BroadBand Adapter? That is to say, exactly what is in the shell?

Is it more than, say, a modified PC NIC? If not, is it based off of some chipset that can be purchased elsewhere? And if so, is the driver information flashed inside the BBA itself or the Dreamcast? Hell...while we're at it, can the Windows CE inside of the Dreamcast be made to see a standard NIC, so even if it can't be used for games, it can still be used as a webserver or something?

So, in a nut's shell, what prevents the world from building a Dreamcast BBA?

Or should I just start saving my pennies for the $200 I'll drop on eBay?

[kendrick]

Briefly, the Dreamcast Broadband Adapter contains a Realtek 8139 processor and an autoswitching 10/100 Mbps Ethernet port. It also contains two proprietary Sega chips of unknown function. I have a BBA and I'm not willing to disassemble it to dump the those chips and see if they're PICs or ROMs or spicy meatballs or whatever.

The interface between the modem or BBA and the Dreamcast is a parallel bus connector running at 25 mhz with a 16 bit signal width. It's completely, utterly not compatible with any PCI or ISA interface. I once estimated the cost of building a homebrew interface would have been around $1200, using off-the-shelf parts.

I've said this before... Rather than hacking a BBA, I would instead hack a modem. Dreamcast modems are plentiful, and if you break one you can get ten more for cheap. Also, more games are compatible with the modem, and several networked games have no idea what to do with the BBA. If you can hack the PIC on a Dreamcast modem and connect its PPP interface to an embedded network device (like a small router or wireless client card) then you have a better device that's already compatible with the Dreamcast parallel port.

-KKC, up too early.

[Blaine]

Thanks.

I've read there are tools you can use to tie in the modem to a lan. a true 33Kb/s would be more than enough for any use for the Dreamcast.

If the word is, it's easier to mod the modulator, I'll mod the modulator.

[kendrick]

If you're crazy enough to try this, keep in mind that you need to keep as much of the original on-board modem code as possible. Since it's not practical to modify every networked Dreamcast game, you need to make sure that the software sees nothing but a standard modem when it makes hardware calls. That means every game will still dial, still submit authentication information, and in many cases still wait for dial tones and acknowledgement noises. On the other hand, since you're not using a real RAS server with real authentication you can use those text strings to make intelligent LAN connections. For example, you could use the modem username and password strings to submit the IP address and subnetting you want to use.

Please share your results if you manage to get this mod working. Good luck.

-KKC, upgrading his car audio...

[Blaine]

Well, what I wound up doing was setting up a PC/DC connection.

Set my DC to use the same DNS settings my host computer uses, set the modem to blind dial, changed a few registry settings on my PC, created an account for the DC to dial in to my PC and then installed WinRoute.

It was pretty simple. It's not quite what I'd want for networking possibilities but it's basically a 33Kbp/s data bus between my PC and DC.

http://consolevision.com/members/mterlouw/

If anyone wants to check out the guide I followed.

Now to get a copy of Starlancer since, apparantly, a very cool dude named Luigi was able to engineer a server using GameSpy. So as of right now Starlancer is pretty much guarenteed to always have a server.

Unfortunately Luigi has shown reservations about working with games that use SNAP as thier protocol so... yeah, it's a one game (maybe two or three if they ever figure out why PBA Bowling and Tetris are being lame with the technology they drummed up).

It's a crying shame, I'd love to play Propeller Arena online.

[kendrick]

One thing to note? Using a PC as a RAS server is a time-honored way of getting a modem-enabled device on your own network. But some games will not dial or make any kind of modem connection unless they detect a dial tone. So keep that in mind if you notice that some games work and some games don't. I have a dial-tone generating line simulator circuit on the back burner that I hope to finish some time before I die.

-KKC, mmmm. Rotini for breakfast.

[Guest]

The Realtek 8139 is a PCI ethernet controller.  I've checked the applications notes (which can be found with a bit of searching on the realtek site) and even it is used in an embedded application the interface to the 8139 is still PCI.  

Having never seen a Dreamcast BBA I can't speculate what the Sega specific ICs are, but something there has to be presenting a PCI interface to the 8139.  The 8139 is a "softNIC" so your not going to be able to use something else without a lost of software changes, but 8139 based PCI cards aren't hard to find.

Looking at pictures of the Dreamcast modem found on google it appears to be based on a Conexant softModem which also has a PCI interface.  There's a SEGA IC on the other side of the PCB.  Maybe this is the same SEGA IC as is used in the BBA?  So it may be possible to combine parts from the modem and a 8139 based network card to make a BBA.  That doesn't mean it's practical though...  

[Blaine]

One thing to note? Using a PC as a RAS server is a time-honored way of getting a modem-enabled device on your own network. But some games will not dial or make any kind of modem connection unless they detect a dial tone. So keep that in mind if you notice that some games work and some games don't. I have a dial-tone generating line simulator circuit on the back burner that I hope to finish some time before I die.

-KKC, mmmm. Rotini for breakfast.

That would be cool, because that is the only real problem with this solution:

That some games will not blind dial. For now though, considering the only games one can play are Starlancer and PSO it's sorta academic. But in the future, it could be a problem.