[Tinyos-help] ADC sampling rate

[Muhammad Azhar]

Hi all,
 
   I understand that the timer used for acoustic ranging done by VU is somewhat different from the original implementation.  I've used the timer provided by VU, but I seem to run into problems in obtaining the correct quantity of data when doing acoustic ranging using micaz motes on TinyOS 1.1.15.
   As a first step, I decided to see how many samples are actually returned by OutsideRangingSensorM (i.e. I used a counter each time bufferIndex was reset).  Hence, in one set of 16 chirps, the counter should return me 16.  However, each time a set of 16 chirps has been sent, the counter returns me a value of 3.
   As a next step, I reduced the implementation to such that only one set of 16 chirps was sampled each time - again it returns me 3 samples.
   Since this program uses ADC.getContinuousData(), I thought that the sampling rate for this ADC was too slow - hence in MicM, I explicitly called ADCControl.setSamplingRate(0) [as this should be the fastest] in StdControl.start(), but unfortunately, it returned 0 samples when I tried running the program.  I also tried it out with different sampling rate and this was what I got:
 
0,1 - 0 samples received
2 - 8 samples received
3 - 7 samples received
4 - 5 samples received
5 - 4 samples received
6 - 2 samples received
7 - 2 samples received
 
   Thus, I'm quite lost as I can't seem to get all the 16 chirps to be sampled.  Any suggestions?
 
Thanks and best regards,
Azhar
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