[Tinyos-help] Time counting

[Michael Newman]

I have a complex application with a half dozen timers. One of the timers is
used to count a clock once per second. The timer is set up with a call that
looks like this:
 
        call TimerClock.start(TIMER_REPEAT,1000);
 
The timer is never stopped or changed. 
 
I count a variable in the TimerClock.fired event. I expect this variable to
reflect the number of seconds since the node has booted. What I observe is
that the counter counts faster than the actual number of elapsed seconds.
 
Given other activities and the possibility of interrupts being off for some
periods I do not expect the timer to fire at an exact interval, what I do
expect is that the frequency of the timer will be exact with some jitter to
the individual firing events. I also expect the timer to never fire early.
 
Has anyone verified that timers actually fire on an exact interval and that
time is neither lost nor gained?
 

 
  _____  


Michael Newman

Dragonnorth Group


319 Dean Rd.
Brookline, MA 02445

Cell: 617 821-4608
Home: 617 566-7975
Fax: 617 566-7975


www.dragonnorth.com <http://www.dragonnorth.com/> 

mnewman at dragonnorth.com

 
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