[Tinyos-devel] [Tinyos-help] RF230 readinf ED instead of RSSI

[Miklos Maroti]

Hi Stefano,

Did you check if PacketRSSI.isValid() returns TRUE? In some cases I
cannot guarantee that the returned ED value is correct.

> 1) The required 140 microsec did not pass, but I think this is not the case

After looking at the code it might be possible (although very
unlikely) that we handle the IRQ, read the status register in 140
microsec. I have moved the reading of the PHY_ED_LEVEL to the end of
the reception in the attached file. Please replace your copy of
RF230LayerP.nc with this one ang give it a try and let us know.

> 2) The ED is an averaged RSSI value calculated from 8 symbols. Maybe
> we read this value too close to the beginning of the start message and
> we measure mostly the "silence" before the transmission. I will looki
> at the code.

Value 0 means below -91 dBm, so probably that value is not a correctly
measured value, so ED measurement did not finish or was not performed.

Miklos
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