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Re: gEDA-user: My current project



On May 7, 2007, at 1:03 PM, Levente wrote:
I'd like to give you a summary about my ongoing project. I am designing a bus system with RS422/RS232 interfaces. It is going to be a general purpose packet
forwarding system built up by cheap devices.

You can find more information on the topic here:

http://web.interware.hu/lekovacs/lbus/index.html

Any idea, question, suggestion are welcome.

I looked over your protocol (I have a background in protocol design) and I like it...clean, simple, and explicitly defined. I do have a couple of suggestions, though. Most of these are geared toward extensibility...If you think about it, some of these things may not be needed now, but if the protocol design withstands the test of time, you may find yourself using it in applications for which it was not originally intended, and designing in some extensibility now may save your butt later.

- Add an octet following FLAG to contain the protocol version number.

- If you add a two-octet field to contain the length of the data field, you will likely find that it eases the design of the firmware that parses the packets.

- If you add a "sequence number" field somewhere in the header, it could be used to send PDUs that exceed the maximum data field size.

- It might be useful to define a "broadcast" address that all interfaces will receive, for things like a "reset" function, etc.

            -Dave

--
Dave McGuire
Port Charlotte, FL




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