[Tinyos-help] Output Power levels CC2420

Rodolfo de Paz Alberola rodolfo.depaz at cit.ie
Thu Feb 28 05:23:14 PST 2008


Folks,

I calculated all values using cubic spline interpolation and obtained
the vectors of the txt file attached

Maybe It will be useful for your experiments with cc2420 radiochip ;-)

-----
Rodo

2008/2/27, bender.13 at wright.edu <bender.13 at wright.edu>:

        This would certainly be helpful for my current work as well.
        
        Now, I have a related question, Does anyone know what the
        default power
        level on the CC2420 is?
        
        i.e. If I just turn on the mote and start sending data, what is
        the RF
        power set to?
        
        Thanks,
        Paul Bender
        
        
        
        Rodolfo de Paz Alberola wrote:

>I am extending a micaz software emulator to support CC2420 and testing
>it with tinyos-2.x.
>
>When dealing with the Output Power Levels that cc2420 support in the
>TXCTRL.PA_LEVEL register, I found the problem that in data sheet they
>don't indicate all dBm values for the different 32 values, the only
>indicate the following:
>
>PA_LEVEL       Pow (dBm)
>31             0
>27             -1
>23             -3
>19             -5
>15             -7
>11             -10
>7              -15
>3              -25
>
>However using the cc2420 driver of tinyos-2.x I can set 32 different
>values, so I would like to know what happend if somebody set a for
>example PA_LEVEL = 21, which Pow(dBm) value should give the cc2420
>radiochip? anybody has the completely correspondence between levels and
>dBm? or even much better a equation to calculate them?


I once set PA_LEVEL = 5 accidentally in a radio measurement. Reception
quality was between setting 7 and 3, so it was apparently sending at
-20 dBm or so.

If you plot the above values, you get what looks like a square root
curve. Maybe it's OK to interpolate the other settings from a fitted
equation like P = a*sqrt(b*PA_LEVEL)+c.

Regards,

Alexander

-------------- next part --------------
PA_LEVEL	31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0

Power (dBm)	0	-9.14E+02	-3.01E+03	-6.10E+03	-1.00E+04	-1.45E+04	-1.95E+04	-2.47E+04	-3.00E+04	-3.52E+04	-4.03E+04	-4.52E+04	-5.00E+04	-5.47E+04	-5.94E+04	-6.44E+04	-7.00E+04	-7.63E+04	-8.33E+04	-9.12E+04	-1.00E+05	-1.10E+05	-1.21E+05	-1.34E+05	-1.50E+05	-1.69E+05	-1.92E+05	-2.18E+05	-2.50E+05	-2.87E+05	-3.30E+05	-3.79E+05 


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