• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 4 answers
  • Subscribers 53 subscribers
  • Views 568 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

CC2650: Unable to set Tx power above 0dBm

CC2650: Changing Tx power in CC2650

PR
Prodigy 30 points

Part Number: CC2650

Hello,

I am having a similar issue as the poster of these two links:

CC2650: Unable to set TX power above 0dBm and Setting CC2650 TX Power

I am currently using a CC2650 Launchpad to test some changes which I hope to implement on a CC2650 chip used in an energy harvesting application. 

Within CCS (8.2.0), I have changed DEFAULT_TX_POWER defined in ble_user_config.c from 7 to 12 (I have tried all values actually) but have not been able to see a change in the RSSI for any such value. From the first link referenced above, it seems that RSSI might not actually be the best way to measure an improvement in TX gain. How can I go about measuring the current in the antenna on the launchpad? I have access to an oscilloscope but am not sure across which resistor I can place the probes. 

Additionally, I have read that one can use HCI commands to set the output power: HCI_EXT_SetTxPowerCmd(HCI_EXT_TX_POWER_5_DBM)

However, where does one call this? I think it should be called in the application folder, but do I call it in scTask, project_zero, or another file? And if so, where in these files? My understanding of the BLE stack is quite weak at the moment, but from the CC2650 datasheet, CC26X0 Developer's guide and Simplelink academy I have not been able to figure out this problem.

Thank you in advance for the help.

PR. 

 

  • 0
    TI__Mastermind 25810 points

    Hey PR,

    Thanks for posting on the E2E forums. We are looking into your inquiry and will reply back shortly.

  • 0
    TI__Mastermind 44870 points

    Hi PR,

    The HCI_EXT_SetTxPowerCmd() is the appropriate function to change the txPower. The following E2E thread provides some information on this: https://e2e.ti.com/f/1/t/757789

    However, to accurately measure the txPower of the board, the board must be set to conducted mode and conducted measurements must be taken.

    Best Regards,

    Jan

  • 0 in reply to Jan
    Prodigy 30 points

    Hello Jan,

    Thank you for your response. I check the thread you linked but still don't understand where to actually call this command. 

    Also, how do I set the boarding in conducted mode? Additionally, what are 'conducted measurements'? Do I have to use an oscilloscope in some way?

    Kind Regards,

    Pawan Ratra. 

  • 0 in reply to PR
    Guru 735705 points

    You can call HCI_EXT_SetTxPowerCmd in your application init function. For conduct mode, I think you should connect your board to spectrum analyzer with cable to do conduct test.

  • 0 in reply to PR
    TI__Mastermind 44870 points

    Hi Pawan Ratra,

    As YiKai mentioned, the HCI function may be called during the init function to ensure it is configured as soon as possible. For conducted mode, if you are using a LaunchPad, a resistor needs to be soldered to divert to TX signal to the external antenna connector. The specific location where the resistor should be placed is shown below:

    Afterwards, a cable should be used to connect a Spectrum Analyzer to the external antenna connector in order to take conducted measurements.

    Best Regards,

    Jan

  • 0 in reply to YiKai Chen
    Prodigy 30 points

    Hello YiKai Chen,

    Thank you for your reply. I have been able to use a spectrum analyzer for the conduction test. However, I believe the argument of the stack API call I use is wrong. I use: HCI_EXT_SetTxPowerCmd(HCI_EXT_TX_POWER_5_DBM); . Should I instead use HCI_EXT_SetTxPowerCmd(TX_POWER_5_DBM); ? 

    Let me know if this is the right one to use.

  • 0 in reply to PR
    Guru 735705 points

    HCI_EXT_TX_POWER_5_DBM is the correct parameter to use