Also see
http://www.octavetech.com/pubs/TB5-01%20Deciphering%20TinyOS%20Serial%20
Packets.pdf under general information.

Regards,
Damien.

-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Harri
Siirtola
Sent: 10 March 2006 08:08
To: [EMAIL PROTECTED]; [email protected]
Subject: Re: [Tinyos-help] Getting extra bytes in CRC in TOS_Msg packet


Hi Umesh,

that's just the ordinary escaping scheme of the 0x7D sync byte. It's
done 
by stuffing a 0x7D into the stream and XORing the actual byte with 0x20 
(0x7D xor 0x20 = 0x5D). In your case, the crc happens to have 0x7D on
that 
line. A search on the list will tell you more if you want.

Regards,

         Harri

At 01:04 PM 3/10/2006 +0700, S. Umesh Babu wrote:

>Hello,
>
>I am sending some packets from two micaz motes to base station.The data

>observed using xlisten program.Some times i am getting crc value 3 
>bytes.Actually it should be 2 bytes according to TOS_Msg structure.Can 
>somebody explain me this.
>
>something like following.I should get all 15 byte packets.But sometimes

>i am getting 16 and larger size packets.I am using 
>tinyos-1.1.7July2004cvs-2.
>
>7e42ffff0481060f0000040100cfa2 [15] 7e42ffff0481060e00fe010200db64 [15]
>7e42ffff048106100000040100487d5d [16]
>7e42ffff0481060f00000202003c45 [15]
>
>Thankyou
>Umesh
>
>
>
>_______________________________________________
>Tinyos-help mailing list
>[email protected]
>https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-he
>lp

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