Hi thanks for the answers Erik,
a. do you know where I can read regarding variable scoping in tinyos? If I
understand it right a variable declared inside an event or command would be
just visible within that scope? If one variable has to be visible has to be
defined at the beginning of the module.. Is that right? What about the static
keyword you mentioned earlier?
b. Regarding conversion formula for the luminance , I am not asking a favor I
am trying to find this myself. I googled it, I found the hardware component
name and look on the manufacturer web site. Where else in this world should I
look for that? I am trying, still to built up understanding
Have a nice day
Alex
On Monday, October 28, 2013 11:32 AM, Eric Decker <[email protected]> wrote:
On Mon, Oct 28, 2013 at 2:33 AM, Alaios <[email protected]> wrote:
Hi,
>I appreciate the answer you gave me.
>
>A. If it has to do with scoping why nesC does not complain for the printf
>statement, that has a variable with no assigned value?
no idea and I'm not going to spend the time to figure it out.
probably because it is static, which means that C knows that is is initialized
on start up. Either zero'd (which is what happens in this case) or
pre-initialized.
What instead of a static variable declaration do a variable declaration inside
the readDone?
I have no idea what you are trying to say in the above sentence. It doesn't
parse.
I am kind of sure that doing the calculations inside the printf("%d",2+3) would
work in todays C compiliers
>
yes.
>B. I also looked on the light sensor my telosb has but I could not find
>anywhere documented the conversion formula being used over the same video.
>Where one can find this conversion formula? I was able to find the temperature
>and humidity conversion formulas from the official datasheet of the chip
>producer.
>
you'll have to figure this one out yourself. I don't have time to figure it
out.
>I would like to thank you in advance for your
help
>
>Regards
>Alex
>
>
>
>
>
>
>On Monday, October 28, 2013 10:23 AM, Eric Decker <[email protected]> wrote:
>
>
>
>
>
>
>On Mon, Oct 28, 2013 at 2:02 AM, Alaios <[email protected]> wrote:
>
>Hi I was looking in the nice tutorial here
>>
>>http://www.youtube.com/watch?v=x0g4uFr44rk
>>
>>and I was wondering why at 34:11 we have to declare one more variable for the
>>conversion formula to work. I guess this is related to the way tinyos works
>>internally.
>>
>
>
>Its not an advanced topic. Rather it is a C variable scoping topic.
>
>
>it also has nothing with making the conversion formula work.
>
>
>It does have everything to do with C scoping of variables.
>
>
>TempRead.readDone is an event that gets signalled by the h/w driver. It is
>basically a call out and you have to have some place to put what you compute
>from the value the read gives you. The value passed in by the driver (when
>calling (signalling) readDone) is call local. its either in registers or on
>the stack. Doesn't have a very long lifetime.
>
>
>So one way is to define a module static, centiGrade. That gets the
>computation value.
>
>
>That is what the tutorial guy is doing by defining the module static
>centiGrade. Because it is inside the implementation block of the module its
>name will be munged by nesc to make sure it is program unique.
>
>
>
>
>
>
>>Can someone shed light on such advanced topic?
>>
>>R
>>Alex
>>
>>
>>
>>_______________________________________________
>>Tinyos-help mailing list
>>[email protected]
>>https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
>>
>
>
>
>--
>Eric B. Decker
>Senior (over 50 :-) Researcher
>
>
>
>
>
>
--
Eric B. Decker
Senior (over 50 :-) Researcher
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