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CC2538EMK: Decrease the RX sensitivity in CC2592EMK

Part Number: CC2538EMK
Other Parts Discussed in Thread: CC2538, Z-STACK


I am trying to decrease the RX sensitivity of the CC2538EMK module (of the CC2538DK), in one of the RIOT-OS examples. I have set the RF power to the minimum (-24) to decrease the sending range, but it seems I failed when it comes to the receiving range. I tried decreasing the RX sensitivity from (-97) to (-20) but the node can still sense and receive packets from other nodes, i.e. both will get RSSI from -91 to -96 within a 6m range.

I also tried to set the RFCORE_XREG_RFC_OBS_CTRLx registers to the following but no changes:


If it is worth mentioning, decreasing RX sensitivity with Openmote-CC2538 Rev.A1 help reduce the receiving range of the node. I wonder if I am missing something on CC2538EMK.

To make it clear, my goal is to decrease the RX sensitivity to the minimum so that its receiving range matches the TX range. What are the possible parameters/registers needed to do so?

Please help,


  • Hello Ahed,

    You shouldn't need to focus on RFCORE_XREG_RFC_OBS_CTRLx for receiver sensitivity changes.  Rather, focus on changing RFCORE_XREG_CCACTRL0 for the correct CCA threshold based on RSSI levels.  Be aware that this forum is not prepared to advise on third-party software solutions, so I don't know if this was already when you speak towards altering the RX sensitivity levels.  Receiver sensitivity of the device itself is defined in its datasheet and should not be modified.


  • Thank you

    I was under the impression that receiver sensitivity is the way to go. To be honest I haven't done a long test on openmote devices (with RIOT-OS) to be really sure about receiving sensitivity. It was a one-time and short test and I should not state that until confirmed.

    I will try to change the CCA threshold and see what happens but may I know what are the values/limits of RFCORE_XREG_CCACTRL0 for CC2538. From the way I understand, it should be between -97 and -73 for CC2538, right?

    I would appreciate your clarification.


  • I'm not sure what the limits are, however it can at least get to CCA_THR_MINUS_20 (-20 dBm as documented in Z-Stack).  You can refer to the TRM.