Hi, I am a little confused too cos the FCS check should be automatically done in the extended mode.
The corrupted packet I noticed had an incorrect length (argument in Receive() event signalled in the app) and also some of the data bytes were corrupted. I have not yet been able to capture another corrupted packet since. Today, I noticed that I was losing a few packets, which I think was due to another Interrupt arrving from the RF230 (crcValid = ! radioIrq;). This however did not result in a corrupted packet. Is it possible that multiple packets arrivng in quick succession might cause data to get corrupted under some circumstances? Thanks, Lewis -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Miklos Maroti Sent: Sunday, March 18, 2012 8:45 PM To: Oldrine Lewis Cc: [email protected] Subject: Re: [Tinyos-help] IRIS motes corrupted data received - CRC check Hi Lewis, In the extended mode (which the RF230DriverHwAckP uses) all packets with an invalid CRC are discarded. The software ack driver (RF230DriverLayerP) does not use the RX_CRC_VALID flag because it was not present in the rev A of the chip. (Looking at the docs know I cannot find a record of this fact, maybe it was there but undocumented?) I am curious how you have seen corrupted messages. Can you have specific examples? Do you see them with the softwareack driver as well? Miklos On Sun, Mar 18, 2012 at 8:28 PM, Oldrine Lewis <[email protected]> wrote: > Hi, > > I have a simple test where one node broadcasts packets and it is received by > multiple nodes. I noticed that I was occassionally receiving some corrupted > packets. The packets were transmitted correctly because one of the other > nodes received the packet correctly. > > On doing a little investigation, I noticed that the lower layer driver > (RF230DriverHwAckP.nc) does not check the RX_CRC_VALID flag in the register > PHY_RSSI (0x06) which is updated with the result of the FCS check on the > received packet. > > > > Would adding another check improve the Receiver reliability? > > > > Thanks, > > Lewis > > > > > > > > > > > > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
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