Sorry about resending this to the list I forgot a vital piece of
information: I am using TInyOS2.x on the iMote2 (but since the
serialactivemessage should be platform independent I don't think the
platform has much to do with it).

 

Thanks again and sorry for the extra message,

Federico Spadini

 

From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Federico
Spadini
Sent: 07 June 2007 16:23
To: [email protected]
Subject: [Tinyos-help] Serial Packet Weirdness

 

Hi Guys,

So I am trying to write a c# interface for the iMote ActiveMessage serial
stack (so namely just a little packet parser so I can send and read data
from the motes).

 

On the mote side I have written a small program wired to
SerialActiveMessageC that can receive three different types of messages (id
10,11,12). Message 12 is my "request" message, simply I am sending a payload
of 00 to the mote to tell it to send me the raw sensor data (I know its not
the most clever way but I needed a small polling implementation).

 

However, I have written my small class and done some protocol analyzing on
the serial port between the java libraries and the mote and between my
library and the mote.

 

I am sending the following packet with my csharp implementation ( I followed
the documentation in tep113 to create the structure )

 

#7E #45 #00 #FF#FF #00#00 #01 #00 #0C #00 #8D#B2 #7E

 

As you can see I have chosen a format type of 0x45 which from the enum
declaration should give me a message with No Acknowledgements.

 

However, this packet structure gives no sign of life from the mote at all.

 

 

When I run the java program it is sending the following message

 

#7E#44#0E#00#FF#FF#00#00#01#00#0C#00#81#2E#7E

 

As you can see there is a significant difference, namely that java is
requesting an ACK and that it is also including the sequence byte.

However I noted that in TEP113 it is mentioned that under the default
implementation the sequence byte is not used under serial active message.

 

The situation gets even more odd when I have the most just send data as it
pleases (so no request from the machine, just a timer using the send
command) the sequence byte is completely left out!!!!

 

Can anyone give me some input into this situation?

 

Thanks,

Federico

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