Pedro: Take a look at the radio control states on page 43 of the cc2420 datasheet. Apart from the IDLE state, there are two more low power modes, namely "power down" and "voltage regulator off". The difference between IDLE and "power down" is that the on-chip 16Mhz oscillator is turned off in the latter state. Not surprisingly, the transceiver draws about 1mA less in power down than in IDLE. On the other hand, it takes about 680us more to start a transmission or to enter receive mode from power down than from IDLE.
To answer your question: the tinyos-2.x radio stack actually goes _below_ the IDLE state in terms of power consumption in LPL mode. In fact, as I recall, not only the oscillator, but also the voltage regulator is turned off when the transceiver "sleeps". Janos On Mon, May 31, 2010 at 1:01 PM, Pedro Nunes <[email protected]> wrote: > Hi all. > > I dug a little bit on mail archives and I found an old thread where it is > said that the IDLE state is not implemented on CC2420 radio stack (please > refer to > http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2005-December/013742.html > to > see the whole thread). > > Don't you think it is very strange that a mote only has two states? > (Sending or Receiving?) > Why don't use IDLE state where battery could be saved? > This way, whenever a mode isn't in TX mode (transmitting), then it is in RX > mode (receiving). Accordingly to MICAz datasheet, RX state has a cost of > 19.7 mA which is higher than any TX state can be. > This kind of behavior will lead us to something like: one application that > sends shorter messages (and therefore is on TX mode for shorter periods of > time) will spend more energy than an application that sends bigger messages > (and therefore will be on TX mode for longer periods). Since the former > application will be on RX mode most of the time it will spend more energy > than the latter (since receiving a message is heavier than sending one cf. > MICAz datasheet: > http://www.xbow.com/Products/Product_pdf_files/Wireless_pdf/MICAz_Datasheet.pdf > ). > > Please, can anyone shed some light here? > > Kind regards, > Pedro Nunes > > On Mon, May 31, 2010 at 5:10 PM, Pedro Nunes <[email protected]> wrote: > >> Hello all. >> >> What are the different states of CC2420 radio stack in TinyOS? >> >> Regards, >> Pedro Nunes >> > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >
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