[Tinyos-help] cc2420 LPL broadcasting

[Flavio Pompermaier]

cc2420 broadcast transmission has a periodic waveform like this (leaving out non-periodic phases such as radio initialization or DELAY_AFTER_RECEIVE listening):

     2  3    4   5 
    | |   |____|  |
 1  | |  /|    |\ |  1  ....
____| | / |    | \|____
    |\|/  |    |  
    | |   |    |   | |

If I understood correctly and supposing that the message to broadcast is 24 bytes long (i.e., 24+11 (MAC header)+2 (CRC)-->37 bytes-->74 symbols. Being 2 symbols sent in 1 jiffy then the tx of the message should theoretically take 1.13 ms):

1) is the transmission of the message (oscilloscope duration: 1.4 ms. Almost equal to the expected value)
2) After transmission cc2420 drops its current consumption for 140 us. 
Probably it corresponds to the tx/rx transition. Am I right?
3 and 4)Total duration is about 2.120 ms. What do they represent? Are they backoff + cca???
5) 140 us. Probably it corresponds to the rx/tx transition.

Am I correct? If so, can I consider tx<->rx  transition to last 140 us?
And what represent phases 3 and 4? And what is the backoff range (in ms)?
Is it correct to consider min backoff = 10 jiffies and max 50 jiffies (min 0.305 ms and max  1.5 ms)? And waht is the duration of CCA?

Best regards,
FP

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