CC2340R5-Q1: About Spectrum Mask of CC2340R5-Q1

Part Number: CC2340R5-Q1
Other Parts Discussed in Thread: CC2340R5

Hi Ti team,

    We are going to do some certification of our bluetooth boards with CC2340R5-Q1 device. We may control our dut by HCI cmmand.

    But we found the Mask shape is a little strange and bottom noise is high, beside there is some burrs. And we try to use SmartRF studio8 to control dut to send signal, it works normally.

    The situation I descibed as below:

 2480Mhz mask control by HCI cmd, Power 8dBm:                                    2480Mhz mask control by SmartRF studio 8, Power 8dBm:                                            


      Why it behaves different Maks shape by diffrent tool? If we would get the Symmetrical mask and no burrs through HCI cmd, How can we do?

      And this is the project we use, if you have any idea, please help us, thanks.

Best Regards,


  • Hi Annie,

    Thank you for the plots - I have looped in someone from my team to follow up and investigate this. Can you please confirm with me which version of the SDK you are using for CC2340R5 as well as what version of Smart RF Studio 8 you have?

  • Annie,

    Can you also confirm which HCI command and with what arguments you are calling on the left picture?

  • Hi Evan,

       What we want to make sure is as the picture below(left picture---control by HCI cmd, right picture---control by SmartRF studio 8):

    1. SRRC in band emission limit is -33dBm/100KHz, and its allow band is +/-250% neccesary band, which is marked blue in the picture, but left picture that control by HCI cmd is so close and even out of the limit. But The margin of the right picture which ciontrol by SmartRF studio 8 is sufficient.

    2. We can obviously see that the bottom noise of the left picture(-40dBm) is higher than the right picture(-55dBm).

    3. And the left picture may disappear some burrses, even it is conducted way and it is in the shielding box.

         Because When we download simplelink_lowpower_f3_sdk_7_40_00_64 version from TI official website, it can not work normally. So we ask TI team as the link CC2340R5: host_test DEMO test failed - Bluetooth forum - Bluetooth®︎ - TI E2E support forums, and TI team provide us the project as the zip file below. Then we import project and flash it into our dut and HCI cmd work OK.  But I am not sure the version, maybe it is simplelink_lowpower_f3_sdk_7_40_00_64.

          So Here is my surrounding:


          Host test LP EM CC2340R5 version: getting from TI team

          SDK Version: not sure

          Code Composer Studio Version: 12.6.0 

          Smart RF Studio 8:  V1.0.2

          HCI cmd-----HCI_LE_TransmitterTest:

           for 1M 2402 TX cmd: 01 1e 20 03 00 25 00

           for 1M 2442 TX cmd: 01 1e 20 03 14 25 00

           for 1M 2480 TX cmd: 01 1e 20 03 27 25 00



          Best Regards,


  • Evan,

        New revelation!

        I changed HCI cmd to HCIExt_ModemTestTxCmd(2480mhz): 01 08 FC 02 00 27, And I got normal Mask:

        But the power is only supporting 0dBm. Because when I want to send Set power cmd, It reminds me unsupported cmd.

         Why different HCI cmd cause different MASK? And if Now the newest CC2340 SDK support the cmd-HCIExt_SetTxPowerCmd?

  • Hi Evan,

        In host test project, I find the place that can change the deafault power of HCIExt_ModemTestTxCmd, I think it works ok.

          But we are still confuse by the cmd, HCIExt_ModemTestTxCmd & HCI_LE_TransmitterTest, how can they cause different result? Please let us know more about it if you have any ideas. Thanks.

          Best Regards,


  • Hi Annie,

    For changing the tx power, could you try using HCIExt_SetTxPowerDbmCmd? You may also use HCIExt_SetMaxDtmTxPowerDbmCmd to change the maximum power first. 

    I am glad youre seeing a good measurement result from HCIExt_ModemTestTxCmd.

    HCIExt_ModemTestTxCmd. starts a continuous transmitter modem test, using either a modulated or an unmodulated carrier wave tone, at the frequency that corresponds to the specified RF channel. This modem test can be used to satisfy in part radio regulation requirements as specific in standards such as ARIB STD-T66.
    Please note that a controller reset will be issued by HCI_EXT_EndModemTestCmd.

    HCI_LE_TransmitterTest is used to start the transmit Direct Test Mode test.

    You may check more information here: 

    We recommend using HCIExt_ModemTestTxCmd for this use case.

    Please let me know if you have more questions. Thank you so much!

    Best Regards,


  • Hi Cashmere,

        Thanks for your information!

        We will use HCIExt_ModemTestTxCmd to get pass the certification with HCIExt_SetTxPowerDbmCmd=8dBm.

        Best Regards,