[Tinyos-help] what is the chance of a timer not getting fired ?

mowrang at ucsd.edu mowrang at ucsd.edu
Fri Sep 16 11:17:37 PDT 2005


Thanks Joe!

I have a question about timers:

I have a module that get called every 10sec using a timer. Each time the
timer get fired I increment a counter by one.

Every 600sec(+some margine to let 10sec timer get fired 60 times) I
send the value of the counter to TOSBase.

I run the program for a few hours and plot the histogram of the counter
values and it is less than 60, 40% of the time. It can get as small as
12!(attached please find the histogram)

I have seen some old postings that mentioned that they didn't collect
enough samples while calling the timer with a specific sampling rate. But
they mentioned HOW inaccurate their samplings were.
Can you shed some light to this problem ?

Note:
1)I am running this module on top of a MAC that puts nodes to sleep
priodically.
2)I am using Timer interface (not TimerMilli)
3)I set timers one shot and start them again when the process is completed.

Also I like to know how exactly the timers work when the MSP430 is sleep.
(I didn't find any posting on this)

You said here
(https://mail.millennium.berkeley.edu/pipermail/tinyos-help/2004-September/005705.html)
that MSP430 goes to sleep automatically when peripherals with high speed
clock are not active. How high this clock should be for MSP430 not to
sleep ?


thanks a LOT LOT!
Maryam


> 2.1V for the radio; the Blue LED cuts out at 2.7V which was probably
> the problem you saw.  I've run the radio down to 1.15V reliably.
>
> -Joe
>
> On 9/15/05, mowrang at ucsd.edu <mowrang at ucsd.edu> wrote:
>> Hi
>>
>> I was running Telos mote to wake-up periodically using Industrial
>> Panasonic Alkaline Batteries.
>> When the battery voltage was 2.3v the LED that was toggeling each time
>> that I turned on the radio, stopped toggling (I was running the code for
>> 4
>> days so I am sure that there is nothing wrong with the code)
>>
>> Is the minimum of 1.8 mentioned at Telos data sheet
>> (http://www.moteiv.com/products/docs/telos-reva-datasheet-r.pdf) only
>> for
>> the processor ?
>>
>>
>> I have read the message at
>> https://mail.millennium.berkeley.edu/pipermail/tinyos-help/2005-January/007193.html
>> However still I didn't get my answer for sure.
>>
>>
>> Maryam
>>
>>
>>
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Counter_hist.JPG
Type: image/pjpeg
Size: 10544 bytes
Desc: not available
Url : http://mail.millennium.berkeley.edu/pipermail/tinyos-help/attachments/20050916/61fd0238/Counter_hist.bin


More information about the Tinyos-help mailing list