[Tinyos-help] RE: Packet information except head & payload in TOS

Jeff Thorn jthorn at octavetech.com
Fri Mar 25 06:30:48 PST 2005


Hello Homin, 
We put together a beginner's guide to understanding the TOS Serial Packet.
It uses the Surge application as an example, but should hopefully point you
in the right direction still. It does cover the CRC as well. 

http://www.octavetech.com/services/pubs.html 

I hope it helps, 

Jeff

-----Original Message-----

Date: Fri, 25 Mar 2005 00:39:05 -0700
From: Homin Kwon <ho.kwon at asu.edu>
Subject: [Tinyos-help] Packet information except head & payload in TOS
	message.
To: Tinyos-help <Tinyos-help at Millennium.Berkeley.EDU>
Message-ID: <000001c5310d$cdbeb310$032aa995 at en4026815>
Content-Type: text/plain; charset="ks_c_5601-1987"

Hi there.

I'm analyzing the packet ( OscopeMsg.h ) to send it from PC to the Mote.
Here, BUFFER_SIZE=10, AM_OSCOPEMSG=10, and AM_OSCOPERESETMSG=32.
But, when I read the packet from serial port in MATLAB, I confirmed 37 bytes
like the below.

126   -----> ???
66     -----> ???
255    -----> Destination address
255    ----->           "
10     --------->AM handler ID
125    ------> Group ID
93     --------->  ??
26     ---------> Message Length
11     ---------> Node ID
0      --------->      " 
70     ---------> Last Sample Number
0      --------->            "
1      ---------> Channel 
0      --------->     "
151     --------> sensing data from here
3
152
3
151
3
151
3
152
3
151
3
151
3
152
3
151
3
151
3         --------> sensing data to there
132     ---------> CRC
150     --------->   "
126     --------->  ???

I don't know where the bytes ( 126, 66, 93 and 126 ) are from and what they
are for.

And I think CRC bytes (150*256+132=38532) are different with the CRC of this
packet.
What section is it for CRC in the packet?

Can you give me some idea about that?

Thanks in advace.
Homin.



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