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Well I'm back after being idle for a while. (on the forums at least) I've been taking a lot more electronics classes in college so this stuff is starting to make a little more sense.
I'm going to study pci and the dreamcast bus a bit longer to try and figure some of this stuff out. Don't think I've given up on the subject already.
~Chaotis
where buy that bba ??? ??? ??? ???
You can find the BBA on ebay and a few other online shops but it's not cheap. That's why we're working on making a new one that is affordable and can be used by homedev games.
I remember trying to install my NIC (belkin F5D5000) on XP and having problems - It thought it was an RTL8139 audio card :-/
I'll pop my case open later and find out - its possible thats its a widely used chip ;)
(edit: I just posted an online help support request at belkin.com asking what the main chip used in the F5D5000 is... doub it'll get anywhere, but the answer could be amusing :P)
Well, like I said, the RTL chip in my NIC card is an RTL8139, but its a revision D, so I dunno if it would work. I believe the BBA is a revision C (too lazy to check)
Belkin got back to me, and told me that it is indeed a RTL8139... not sure on the revision though.
I have another card somewhere, so I'll have a look at that too (its made by 3com, so it'd be intresting to see if its used there too).
Damn. Haven't been here for a while (oh and BTW that thing I mentioned about the Yamaha CRW-F1 in my last post is complete and utter nonsense) =P
But, I found a nice page a while ago, for anyone who wants to know how to get a PCI slot - well, quite a lot more than that actually - free from an old motherboard in a rather neat way. Obviously I cannot guarantee whether everything will work after you have done this, though =P
And here it is: http://www.savel.org/hardware/solder/index-en.html
EDIT: Hmm, how odd, hyperlinks are the same colour as plain text on this board - how's anyone supposed to see a hyperlink in a post? Meh. =P
Well I'm glad to see that others are still keeping this thread alive while I'm away doing stuff. ^^ Just finished another digital electronics class today. (supposed to take all 16 weeks. :-p) And I'll be starting another next week. Can't tell you how much more things make sense thanks to those classes so far.
I've seen a lot of those chips around for pretty cheap (5-10$), gonna depend on a lot more things that are needed to see what kind of money we're talking about to develop one. (I'm always broke. ^^;)
I'll take a look at that desoldering link since I have a few mobos lying around with pci slots on them, still need to get myself a new dc to work with too so I can get back to work on this project. Everyone keep a lookout for any information on pci/dc parallel/ethernet ic's and stuff that might be useful; we can beat this yet.
The requiered parts are not much of a problem, at least out here in europe. mikrokontroller.net pages list many shops, with customer reviews, which will get all of this stuff. For byung one piece, the price for network chip + PHY + jack should not exceed 15 EUR.
What is much of a problem, is a PCI bus. I've talked to a guy who develops all sorts of network stuff professionally, and he is afraid that the realtek chip used on the original BBA, as a true PCI chip, makes use of busmastering feature, which allows the target to control writes to memory. It might be very hard to implement a full-featured PCI host. I'm yet to read the BBA drivers from KOS thoroughly, but even if KOS accesses the bridge in a simple manner, and one can make a device work, it might still be that it won't work right with original games.
If the compatibility with original games is not requiered or not quite possible anyway, there are probably better ways to build a network card. One can use some NE2000 clone, like RTL8019AS (10 MBit), CS8900 (?), AX88796, LAN91C111 (both 100 MBit). These devices are all ISA, but also compatible with a broad range of microcontrollers and other stuff. I'm about to read the data sheets, but my first impression is that they are really flexible, perhaps they can be driven with the native DC external port frequency for maximum performance.
You have probably all seen bITmASTERs page where he wires up an ISA card to DCEXT through a couple of driver chips. NetBSD testing revealed it to be quite slow, around 200 kb/s on recieve. It is OK for developer purposes, because faster than even USB to Serial though.
There was also an old LAN Adapter for Dreamcast, HT-0300 (while the modern one is HT-0400/0401). It was based upon the same simple bridge (ISA?) like the modem, and had the trouble that all I/O was PIO bytewise, whereas the usual mode would be DMA. PIO is slower and most importantly consumes a lot of CPU time, while the DMA basically does not. This is the reason HT-0300 is not supported by games (would kill performance) and perhaps one problem that we'd have to face while designing new hardware.
I don't know much shit about designing hardware and could use any help, but i think i could organize manufacturing without much trouble, probably even in very small quantities.
Nice knowing the interest isn't all dead btw!
Intesting. I am sure that the D revision will work. Why? Because the point of revision is to revise the old system. Therefore, it SHOULD still be compatible (kind of like how you can pop in a Motorola 68010 to replace the Genesis' 68000, faster and a little more streamlined).
All I can say after that, is, you are still going to hit a brick wall with the Sega proprietary ROM chip that is on the BBA. If you could find some way to flash the data, then you can copy it to a compatible chip. However, unless Sega gives you proven permision, that is very Illegal.