Hi experts,
We have to design a special device....to implement a special protocol on top of ethernet. Rabbit 4k devices look like a good choice, but it comes with TCP/IP stack built in.
How easy it is in Rabbit 4K to get rid of the the TCP/IP stack from OS and take charge of packets arriving over ethernet.
I am aware of NE2000 compatibility. Please let me know whether it will be helpful and any other pointers will be of big help.
TIA,
Krishna
I don't believe you get sourcecode to this, so the difficulty level is "write a new OS".
The source code for the tcp/ip stuff is included, so it will be a convenient starting point for writing your own drivers. As far as I know if you never do the calls to set up the tcp/ip stack, it's never going to get in the way of whatever driver you write. Talking to the on-board ethernet hardware is pretty simple with or without dma.
Monte (yes, the Monte who designed the Rabbit 2000, 3000, 4000 and beyond)
[puzzlement] What parts of it are closed-source then? When I was negotiating putting one of the Rabbit parts into a design, I was told that various stuff (e.g. SSL) had been hand-optimized for specific Rabbits, and couldn't be ported to other Rabbit parts.
It's not that it's closed-source, it's that some modules (SSL being the one that I am aware of) use features that are not backwards-compatible between generations. In particular, SSL uses the "array multiply" instructions when targeting the R3000A or R4000. These instructions were designed specifically for this application. Duplicating their functionality in an R2000 or R3000 would be non-trivial if starting from the source code targeted at the later parts.
Monte
Hi Monte. Nice job, sir. I've used the Rabbits, and have been very happy with them. (This from someone who has otherwise learned the hard way to be very wary of 3rd-party embedded code ;).)
And welcome to the ng.
Steve
Why, thank you. I've been lurking here for years, but seldom have anything to contribute.
Monte
Thanks Monte for the response.
We got hold of a Rabbit 4K and could go through the lib files. Sounds good place to start digging. But we have encountered a strange issue.
I tried the sample Ping utility, which works great as long as our network is not connected to Internet. None of the packets appear outside chip, though the traces show that packet has been handed over to ifte->ncd->sendpacket in ip.lib.
The packets appear....(which I could confirm using sniffer) as soon as I disconnect the router from Intranet.
The configuration...
IP Address: 192.168.1.65 and many more...as trial Mask: 255.255.255.0
Tried to see if adding router, static router paths or DNS addresses would help. So far no success.
I saw same behaviour with raw packets, and trying to debug what could be the problem.
Any hint will be highly helpful..
TIA.
Krishna
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