c - A way to convert byte stream to packet stream in C89 on an embedded device -


I am working with an embedded device that connects to PC rs232 (rs232 on USB).

I am thinking of developing my own protocol:

& lt; Magic & gt; & Lt; LENGTH & gt; & Lt; Binari Data & gt; & Lt; CRC & gt;

But I do not want to modify the wheel again.

Please note note that: I am thinking of a much restricted device: 4kb of RAM, no kernel, and no standard cobb.

Can you think of a standard way (perhaps Open Source Library) to do this?

If you do any best practice in the code of your own solution?

  • Do you also use magic byte at the end of the package?
  • Is it better to use time intervals instead of delimiter?
  • How can you get started with the package in a stream binary data?
  • Is it better to use Text Protocol?

Update: Please read the question. I should not ask for the library, but for good practice.

See details about a simple protocol. / P>

To respond to your specific points:

  1. "magic" bytes at the end of the packet do not do any harm, but if you already know that How long is the packet should be, and the CRC should be.
  2. It may be sensible for the specified time period, so if there is a large difference between the bytes within a packet, an error has been flagged. After use, I am not sure of the value of using the delimiter based on the deadline.
  3. Do you mean, "How can you find the beginning of packets in a stream of binary data"? If this is the case, then perhaps specify the minimum difference between the packet, and / or the recipient needs a single note after each packet.
  4. This makes it easy for debugging, and no special software is required on PC, but very efficient. Of course, if text-based is more important than the usability efficiency compared to the system, then it is perfectly appropriate.

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