Hi,
please note that CC2420ControlP shifts the RSSI reading by 0x7f, as you can
see from this function copied from CC2420ControlP.nc:
event void RssiResource.granted() {
uint16_t data = 0;
call CSN.clr();
call RSSI.read(&data);
call CSN.set();
call RssiResource.release();
data += 0x7f;
data &= 0x00ff;
signal ReadRssi.readDone(SUCCESS, data);
}
thus you'll have to subtract 0x7f and then subtract 45 (refer to the CC2420
datasheet to understand better how RSSI sampling works) to get the RSSI value
in dBm.
Please send further questions directly to the mailing list, thank you.
Regards,
Giuseppe
On Wednesday 18 May 2011 15:41:58 Lyubomir Ivanov wrote:
> Hi Giuseppe,
>
> We have already implemented in the same way as you said. But anyway thanks.
> May be because I was in hurry I posted such a meaningless
> title of the topic. I do not know if you have noticed
> that getting the environmental
> RSSI
> by using
> cc2420controlC
> component gives different result. Yes, it is normal to have difference in
> the result, but in this case it supposed to substract more, because the
> raw values are more 70. Naturally, these values
> depend
> on
> the
> environment. So if you know
> with how much approximately
> to substract of this value, let me know ;]
>
> Thank you in advance.
>
> >-------- Оригинално писмо --------
> >От: Giuseppe Cardone
> >Относно: Re: [Tinyos-help] !!!
> >До:
> >Изпратено на: Сряда, 2011, Май 18 19:38:45 EEST
> >
> >Hi,
> >
> >you can find a sample application that measures environmental RSSI using
> >the CC2420ControlC component in apps/tests/cc2420/RssiToSerial . In
> >general, you have to wire a Read interface to CC2420ControlC.ReadRssi and
> >call the read() function, the calling component will be notified by a
> >sendDone event containing the measured RSSI value.
> >
> >As a side note, for the next emails that you'll send to this mailing list,
> >please use subjects more meaningful than "!!!" (for example: "Measuring
> >environmental RSSI with CC2420"), it makes reading the mailing list
> >threads much easier to follow). Thank you.
> >
> >Regards,
> >
> > Giuseppe
> >
> >On Wednesday 18 May 2011 09:13:54 Lyubomir Ivanov wrote:
> >> Hi guys,
> >> I am facing a huge problem. I want to read the RSSI from telosb when it
> >> is not receiving packets. In such order I want to send to this value to
> >> my pc using the SerialForwarder, because I want to see what is the
> >> value when there isn't useful received signal. I know that that there
> >> is an interface called ReadRssi provided by CC2420ControlC component,
> >> but I don't how to get the value when there isn't stream of packets. I
> >> will be grateful if someone has an idea how to achieve this. Thank you
> >> preliminarily /n01d
> >
> >--
> >Giuseppe Cardone, Ph.D. Student
> >DEIS-LIA - University of Bologna
> >E-mail: [email protected]
> >Web: http://lia.deis.unibo.it/Staff/GiuseppeCardone/
> >
> >LA RICERCA C’È E SI VEDE:
> >5 per mille all'Università di Bologna - C.F.: 80007010376
> >http://www.unibo.it/Vademecum5permille.htm
> >
> >Questa informativa è inserita in automatico dal sistema al fine esclusivo
> >della realizzazione dei fini istituzionali dell’ente.
> >
> >_______________________________________________
> >Tinyos-help mailing list
> >[email protected]
> >https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
--
Giuseppe Cardone, Ph.D. Student
DEIS-LIA - University of Bologna
E-mail: [email protected]
Web: http://lia.deis.unibo.it/Staff/GiuseppeCardone/
LA RICERCA C’È E SI VEDE:
5 per mille all'Università di Bologna - C.F.: 80007010376
http://www.unibo.it/Vademecum5permille.htm
Questa informativa è inserita in automatico dal sistema al fine esclusivo della
realizzazione dei fini istituzionali dell’ente.
_______________________________________________
Tinyos-help mailing list
[email protected]
https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
