Help with new BBA adapter (cont. from Cluster)

[Chaotis]

From what I saw, the ISA only runs at 8mhz or so. That might make it a little hard too, and I bet that would only allow a base10 ethernet and waste a lot of what the port could handle. Of course I'm not an expert like I've said so if anyone knows otherwise feel free to correct me.

[Alexvrb]

Because even if you could get a full speed ISA bus, it's not very fast?

[quzar]

Still significantly faster than the serial port?

[Chaotis]

Yeah, full speed ISA would be some 50x faster than the serial port but we could still get like 5x more than that if we can make use of a base100 ethernet. If we can find a 16bit one that runs at a higher mhz that would be really helpful.

[Rufus]

I'm sure that everyone has seen this http://www.realtek.com.tw/products/p...aspx?modelid=6

It supports PCI clock speeds from 16.75 to 40MHz and can be interfaced to PCI, mini-PCI or Cardbus...

Couldn't someone have a look inside their own BBA and let us know whats inside? Wouldn't that be a easy route to develop a "replacement"?

[quzar]

The fact you have to consider though is that anything that you send over a bba would be well under 16mb as it would have to fit into the DC's ram AND have space to execute. Therefore 16mbps would pretty much be the maximum needed for anything. 16bits x 8mz =~ 16mpbs that means that in under a second you could send all the data you want to. IMO that is an acceptable speed =P.

[Chaotis]

The BBA uses some proprietary logic chips to do all the work and so far nobody has let us know how they do it. So we're stuck trying to find our own way. Still hoping someone has a BBA and can give us more information to go on. Thanks. ;D

Edit: Wow, we posted at the same time...

Well I wanted to get it as fast as possible in order to work as a cluster. Even though it can send all the data it could hold in memory it would in this case be processing it and sending it back just as much. Was hoping to kill two birds with one stone. ^^

[semicolo]

Again the pictures :

http://perso.wanadoo.fr/pryonic/photos/BBAcote.JPG
http://perso.wanadoo.fr/pryonic/photos/BBArecto.JPG
http://perso.wanadoo.fr/pryonic/photos/BBAverso.JPG

There's really a Realteak 8139 in it, the trouble comes from the Sega chip
Maintaining compatibility with the official BBA would be nice, there are good informations in kos kernel on how the BBA talks to the G2 bus (DMA etc ...)

[Alexvrb]

Quzar, some thoughts:
1) If you're going to build a custom piece of hardware anyway, why would you purposely use an older, slower interface if you're still going to have to fudge the thing just as much.
2) We're not currently talking about just sending data to store in memory. If you're designing a cluster, you give it a piece. It chugs it, sends results, gets new piece.
3) Assuming you WERE just using it for dev purposes (or otherwise just filling the DC's RAM for the hell of it) the serial port would suffice and indeed be a whole lot easier/cheaper to work with.

[Chaotis]

Yes, that would be very nice to keep it backwards compatible with the previous BBA(s?). Is there any information on the glue logic chips that sega used or can anyone maybe probe it to find out for us. (doubting, but would be really helpful) Also, if anyone has the BBA, how fast does it currently send/recv data?

I was looking at making this replacement because it would be helpful in so many different things. Possible cluster or online vs dev games, development of software, all kinds of stuff. Hope we're up to the challenge.