[Tinyos-help] Tiny OS packet format

Terence Joseph tjormor at hotmail.com
Mon Sep 19 03:11:18 PDT 2005


Hello All,

I have been playing around with two tmote sky's.  One running TOSbase and 
the
other running either CntToLedsandRfm or SenseToRfm.  I have built my own
application which basically reads the data from the serial port and I have
just a quick question about the raw data I am receiving. In both
applications the data is similar to that given below.

Hex:    04   01   08  73    FF   FF   FF    FF   04  7D...
       ...5D   73   01  01    00  D9  9E    7E   7E  42

Dec:   004 001 008 115  255 255 255 255 004 125...
       ...93  115 001 001  000 217 158 126 126  66

As you can see there are 20 bytes in total.  Call them Column 1-20 (Col 
1-20).
I have assumed the following (please correct me if I'm wrong):

Len (Col 1)
FCF (Col 2-3)
DSN (Col 4)
Dest Addr (Col 5-6)
Dest PAN (Col 7-8)
AM (Col 9)
Grp (Col 10)
Data (Col 11-18) - 8 Bytes in total here.
FCS(Col 19-20)

I have assumed this because I have read that the following are the
lengths for each of the fields (in bytes):

Len - 1
FCF - 2
DSN - 1
Dest Addr - 2
Dest PAN - 2
AM - 1
Grp - 1
Data - <= 28 (in this case I have assumed 8 is the correct value as that's
what is left over when I account for everything else)
FCS -  2

The main thing I am interested in is the data field.  If it is 8 bytes, how
are these bytes organised?  Which is the actual data from the 12 bit ADC for 
SenseToRfm
or the Counter values from CntToLedsAndRfm?

When I use it with CntToLedsandRfm only columns 4, 12, 16 and 17 change
however when I use it with SenseToRfm only columns 4, 16 and 17 change.

Best Regards,
Terence.

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