Invalid Packets

[JavaRN]

I'm writing a simple application to send robot moves from my PC to the CM-5 using Zig-bee. The program logic seems ok but sometimes I receive invalid packets from the CM-5, for example packets without headers (FF 85), or without MSB. I've spent the whole day debugging the program and as I said there seems to be no error in the logic, in fact most of the times it works fine, but for no specific reason I get one or two of these malformed packets, which are enough to make the program stop.

Is it normal to get malformed packets?

If some of you have any feedback I would really appreciate.

[tom_chang79]

I wonder if it's just loss through the air since it's wireless, in the form of RF.

[JonHylands]

I get bad packets every now and again using a wired connection. Your code that handles responses has to be very flexible and resilient to bad responses, because there is very little in the real world that is perfect.

- Jon

[JavaRN]

Thanks all for your help, right now I am designing a packet recovery algorithm which is working fine for some (not all) the incoming invalid packets (the ones with no headers). I guess with some more debugging I can achieve the final aim. Thanks again.



Charles.

[Dewey]

The CM5 Zig100 output is common with the CM5 Serial cable output. Zig100 and cable input are switched.

This means that any CM5 transmission goes to both the Zig100 and the cable, any BCP output intended for the cable/PC terminal will also be Txed by the Zig100. This would be seen by your Zig100/PC setup if you haven't set up a screening for the correct protocol. Any debug code using the PC/cable/Terminal will make matters worse!

Dewey

[JavaRN]

This means that any CM5 transmission goes to both the Zig100 and the cable, any BCP output intended for the cable/PC terminal will also be Txed by the Zig100.

I noticed that, in fact I will try something different. I will send the data using packets and try to use the print command to get the results back.

Thanks Dewey