Hello Umit and Miklos, I don't think there is a conversion formula for the LQI between the values from RF230 chip (Iris mote) and CC2420 (Shimmer mote). The IEEE 802.15.4 standard defines that this parameter have to use a range from 0 to 255 but a specific formula to calculate the LQI is not defined. The RF230 chip calculates the LQI directly in hardware (values from 0 to 255) but the CC2420 radio chip only provides an average correlation value (values from 50 to 110) which can be used to calculate the LQI in software using RSSI value or through packet error rate measurements but please refer to the CC2420 datasheet page 49.
I used the RF230_RSSI_ENERGY flag in my Makefile for the ZigBit Amp (RF230 radio chip) to get averaged RSSI values over 8 symbol periods because CC2420 calculates its RSSI value over 8 symbol periods, too. For me it was possible to get both, LQI and RSSI (averaged over 8 Symbols with RF230_RSSI_ENERGY flag) values. For the RSSI to dBm calculation I used the information in the datasheets: RSSI_dBm = PHY_ED_LEVEL -91 For CC2420: RSSI_dBm= RSSI_VAL - 45 Regards Peter On Tue, 2011-04-19 at 11:44 +0200, Miklos Maroti wrote: > Hi! > > Look at the RF230ActiveMessageC component, and there you will see the > PacketRSSI interface. Also, read the README in tos/chips/rf230 > directory. You can either obtain the LQI or RSSI, but not both on the > IRIS. As for the conversion, use the datasheets of the AT86RF230 and > CC2420 radios to figure it out. > > Miklos > > On Tue, Apr 19, 2011 at 10:08 AM, CELALETTIN UMIT BAS <[email protected]> wrote: > > Hello, > > > > I have problem on reading LQI and RSSI values from a iris mote. In one > > of my application I was using RSSI and LQI values. I used to use > > shimmer motes with tinyos. Both of LQI values were provided in > > CC2420Packet interface with the functions of getRssi and getLqi. But > > now I am trying to use same application on a iris motes from crossbow. > > But I am not able to find the same interface or any interface > > suggesting LQI and RSSI values. I found variables as strength and lqi > > on TOS_MsgPtr. But these provides numbers in a different(ie. LQI in > > shimmer (50,100), LQI in iris (0,255)) range than before. Is there any > > conversion formula from one to another or should I read these values > > from somewhere else on iris. > > > > Thanks in advance... > > > > C. Umit Bas > > Graduate School of Sciences & Engineering > > Electrical and Computer Engineering > > M.Sc. Student > > _______________________________________________ > > Tinyos-help mailing list > > [email protected] > > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
