Is there something in the program that takes around 200ms to execute? Like the sampling itself? It sounds like you have a beat between your timer and some internal cycle.
I just looked at the glossy for the MSP410 and there is a curious spec for PIR "bandwidth" of .01-.15Hz, which may be a settling time for the sensor. The max value is within a GA of 200ms for all practical purposes... MS campbell gao wrote: > > hi,all > now i have written a program which is used to detect body motion in > MSP410.My program is a loop cycle, which every time is started by a > timer and then run step by step ,at last wait another timer fired. > > i downloaded my program and have done some experiments. > > --1-- > after several times experiment , i find a special and surprising phenomenon: > > when my time is fired in 500ms which begin to repeat my program in 500ms > , the data i get tell me that i just get nearly 2 times one per one > second.It is nearly normal! > but when i change the timer in 100ms to fire ! what a surprise! i just > get mean a little more than 4 times per second!! why ??who can help me > to exlpain it ?? is it by reason of hardware ?? > > more surprising is that when timer is in 25ms , what i get is just > similar to 100ms ,it is nearly 5 times per second!! > > why ??who can help me to explain it ?? is it by reason of hardware ?? > > --2-- > and could i get the system time of mica2( or MSP410)? so maybe i can get > the runtime of my program?? > > --3-- > in the MSP410's PIR.nc and PIRM.nc files , i find the PIR.IntEnable() > and PIR.InterruptEvent() function. Any one could tell me what is their > usage??when should i use them ?? > > > best regards > > -- > 祝好，此致 > 敬礼 > > Campbell > -------------------------------------------------------------------------------------------------------- > SNARC > Sensor Networks and Application Research Center > http://snarc.gucas.ac.cn/index.htm > > Our Mission > To be one of the best groups in the area of sensor networks research > , by successful completion of key projects > , publishing high quality papers and transferring technologies > and know-how to industries > -------------------------------------------------------------------------------------------------------- > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
