[Tinyos-help] MViz

[Muhammad Azhar]

Hi all,

I have some questions with regards to the MViz program 
(tinyos-2.x/apps/MViz).  I noticed that it is quite similar to the 
MultihopOscilloscope (I shall phrase it as MO as of now) program, but there 
are some things that I do not quite understand (maybe I got some concepts 
wrong).

1)  In MO (module), specifically Boot.booted(), local.version was 
initialised to 0.  However, there was no initialisation for local.version in 
MViz.  Does TinyOS automatically initialise it to 0?  Also, will the version 
ever change, since I don't see it being "changed" anywhere else (except 
Snoop.receive() - but since it was never manipulated in the first place, 
will there be a change in version?)

2)  Also, in startTimer(), MO has a line:
if (call Timer.isRunning()) call Timer.stop();
This was not seen in MViz.  Will it cause any overflow?

3)  What exactly does Snoop.receive() do?  I am quite certain the situation 
is one where the motes are of the same collection_id_t, but how is it 
possible for the mote to "overhear" other traffic in the network?  Is it 
because the motes have "parents", and, they would have to "report" to their 
parent, but instead, they "overheard" some packets from another mote of the 
same collection_id_t, or, if they are parents themselves, they actually 
"overheard" some packets from other motes of the same collection_id_t?

4)  In MViz, I don't really see the need for the "reading" variable, which 
is set to 0 only in Timer.fired(), and is never used in any other "methods". 
  Hence, is it possible for the program to work without this variable?

More Questions:
5)  Is it possible for me to get 2 sensor readings (one for light intensity, 
one for temperature) at one time?  From the code, the Read interface is 
connected to the sensor.  Hence, if I were to define 2 read interface - 
assume one is ReadLight and another is ReadTemp, is it possible to get two 
sensor readings (assuming I do not want to use the variables 
link_route_value, as well as link_route_addr - in the first place, is it a 
must to use the interfaces CtpInfo and LinkEstimator, where both are wired 
to CtpP, in implementing a multi-hop network)?  If this cannot be done, how 
is it possible for me to "multiplex" the data (i.e. after reading light 
intensity, my next reading for data should be temperature)?

6)  Is there any method that I can use so that I can get the time the 
reading was made?

7)  I would like to save the values of the data of all the motes at certain 
fixed time intervals, instead of just displaying them using tos-mviz.  If 
this is not possible, is it possible for me to modify the automatically 
generated java file?

Thanks in advance if you have solutions to my questions...

Azhar