On Tue, Jun 17, 2008 at 11:25 PM, Shomnat Mitra <[EMAIL PROTECTED]> wrote:
> Thanks for the reply. > > One more related question. > > I used the LocalTimeMicroC component in Tinyos1.x, and wired the LocalTime > interface to my application, to measure the time difference between the > sending of a packet and receiving an ACK(using GenericComm ). > > I just did: > > sendTime = call LocalTime.read(); // just before sending > > and > > receiveTime = call LocalTime.read(); // upon receiving the ack packet > > and computed > > timeDiff = receiveTime - sendTime > > This is giving me values like: 14,857 > > So is this value in exact Microseconds? If it is - then I think I am > getting decent values: 14.8 ms - time to send a packet and receive its ack. That is how I would read it. In T2, I'd use TMilli and the call looks like call LocalTime.get(). Do you really need uS resolution? eric > > > Somnath Mitra > > > > On Wed, Jun 18, 2008 at 12:57 AM, Eric Decker <[EMAIL PROTECTED]> wrote: > >> >> >> On Tue, Jun 17, 2008 at 8:35 PM, Shomnat Mitra <[EMAIL PROTECTED]> wrote: >> >>> Hello , >>> >>> The telosb has a 32768 Hz crystal. >>> >>> So the lowest precision of time that it can measure is : >>> >>> 1/ 32768 seconds = 30.517us >> >> >> That is the underlying clock running timerB which is used to provide >> TMilli. >> >>> >>> >>> So when we use a Timer<TMicro> interface , is this precision we get ? >> >> >> TMicro is actually based on the main system clock running TimerA. It >> clocks at 1MHz >> and the 32K timer is used to calibrate it. This is the timing source used >> for TMicro. You >> really do get close to 1us ticks. >> >> eric >> >> >>> >>> >>> What about LocalTime.get() 's precision ? >>> >>> Thanks in advance , >>> Somnath Mitra >>> >>> _______________________________________________ >>> Tinyos-help mailing list >>> [email protected] >>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >>> >> >> >> >> -- >> Eric B. Decker >> Senior (over 50 :-) Researcher >> Autonomous Systems Lab >> Jack Baskin School of Engineering >> UCSC >> > > -- Eric B. Decker Senior (over 50 :-) Researcher Autonomous Systems Lab Jack Baskin School of Engineering UCSC
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