[Tinyos-help] time to turn on/off Radio CC2420

[Abhishek Anand]

No the radio is not turned off by default after sending every message.
Even if you have defined LOW_POWER_LISTENING, the radio is turned on and off
regularly maintaining a duty cycle. I dont know what RxTxDelay is. It had no
mention in the CC2420 datasheet.
And I tested experimentally the radio starting time on my micaz motes....
the reults are appended

(you can see that the diff b/w startCommandIssueTime and startDoneTime is
always 2ms)
(note that the value 2ms is accurate only to the order of milliseconds)

Messsage <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 252]
  [startDoneTime= 254]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 502]
  [startDoneTime= 504]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 752]
  [startDoneTime= 754]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 1002]
  [startDoneTime= 1004]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 1252]
-- INSERT --
Messsage <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 252]
  [startDoneTime= 254]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 502]
  [startDoneTime= 504]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 752]
  [startDoneTime= 754]
---------------------------------------
Message <BlinkToRadioMsg>
  [nodeid=0x1]
  [startCommandIssueTime= 1002]
  [startDoneTime= 1004]



On Thu, Jun 12, 2008 at 6:23 PM, salvatore galati <slimslim182 at gmail.com>
wrote:

> Hi all.
> Sorry for my frequent questions.
> I'm a student of Informatic Engeenering of University of Pisa.
> I'm working with TmoteSky motes and TinyOs 2.x on cygwin.
>
> I founded a difference between my tossim simulation and realt tests with
> motes.
> In Tossim simulation the average message transmission time is about 6,8 ms
> In TmoteSky the average transmission time is about 10 ms.
>
> I found in   http://csl.stanford.edu/~pal/pubs/tinyos-programming.pdf
> that
>  time to turn on/off the CC2420 radio is about:
>
> 1.)    0.6ms ------> Turn on the voltage regulator
> 2.)    X ms (depends on contention) ------>  Acquire the SPI bus to the
> radio
> 3.)    0.86ms ------> Start the radio's oscillator by sending a command
> over the bus (0.86ms)
> 4.)    0.2ms ------> Put the radio in RX mode (0.2ms)
>
> so total time to turn on/off radio is about ( minimum value )  1,66 ms
>
> My question are :
> -- This time is  the RxTxDelay ? so after sending a message the radio turns
> alway off and then turns on?
> -- This time to turn on/off radio is the same for micaz and telosb/TmoteSky
> motes?
>
> If this time is the  RxTxDelay--->so dafault value in Tossim "mac" object (
> = 0,18 ms  from "opt\tinyos-2.x\tos\lib\tossim\sim_csma.h"  )
> is too low respect to this value of 1,66ms , it can be possible that
> difference, between average transmission
>  time in tossim and in motes, is caused by this too low RxTxDelay default
> value  in tossim configuration parameters for a CSMA link.?
>
> thanks very much for your answers
>
> Best Regards
>
> Bye Salvatore.
>
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