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Using RSSI sensing in WOR

Nad Gilbert
Prodigy 200 points
Other Parts Discussed in Thread: CC1101

I'm trying to use the CC1101 in WOR with RSSI detection.  When I set  MCSM2.RX_TIME_RSSI=1, every so often (~2hours or more) of being in WOR the CC1101 will issue GDO2x=06h with a pulse width corresponding to the correct packet length.  The data in the RX FIFO is garbage but it does not give me an underflow or overflow error.  I'm using the CC1101EM_434MHz evaluation board.  It will do this with antenna connect or not connect.  I have another CC1101 which is doing nothing put receiving and it does not see the packet.  I’m assuming the garbage data is just the power up values in the FIFO.  It is not consistent, however.  I am sending out the EVENT0 signal on GDO1 during WOR at a 90ms period.  When I set MCSM2.RX_TIME_RSSI=0 I don't see the problem.  Are there some settings for AGCCTRL2, AGCCTRL1, and AGCCTRL0 needed in order to use RSSI detection in WOR?  Is this a know bug?

  • 0
    TI__Genius 14940 points

    Do you have additional qualifications turned on for your WOR work?  Such as relative threshold, etc.  Notice that if you turn on the radio every 90ms, and if you are only using a 16 bit sync word, then assuming you have a uniformly distributed noise, you could get a false sync word every 1.7 hours on average.  If you have your sync word set to 15/16 then you can get a false detection every 50 minutes or so.  Your code needs to handle this by doing some sanity checks on your packets received.  There may well be times when you just need to toss the packet and wait for the next one just as you would do if an actual packet was received in error.

    Jim Noxon

  • 0 in reply to Jim Noxon
    Prodigy 200 points

    We have PKTCTRL1.PQT=2 and MDMCFG2.SYNC_MODE=7, 30/32 + carrier sense threshold.  We have AGCCTRL1.CARRIER_SENSE_REL_THR=2.  What other qualifications would you suggest?

    Thanks,

    Nad