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LAUNCHXL-CC26X2R1: Some connection issues with RPi 3B

kazola
Guru 18595 points
Part Number: LAUNCHXL-CC26X2R1
Other Parts Discussed in Thread: SYSCONFIG

Hi all,

I am back at CC26x2r after a while Slight smile

I have a quick question, well, 4 small ones, since sometimes it takes a lot of attemps to connect my cc26x2r to a linux raspberry system. Such linux system seems to always work at min_ce 24 and max_ce 40 (x multiplier).

  1. Does using RCOSC in Sysconfig affect the probability of a successful connection?
  2. Does using RCOSC in Sysconfig affect the current consumption of the device? Can I have some approximate numbers?
  3. As far as I know, there is no option in cc26x2r to change the LF clock source, is there? If so, does using it affect the probability of a successful connection? What about the current consumption?
  4. I am planning to set the connection update parameter request in sysconfig to simply "accept all". Do you think this is wise? Can this increase the probability of successful connections?

Thanks a lot for your time and have a nice Friday!

  • 0
    TI__Expert 3730 points

    Hi Kazola, 

    Thanks for reaching out! We will look into your questions and get back to you after the weekend. In the meantime, can you share what version of the SDK you have installed and which example project you are using for your implementation?

    Best regards,

    Luke

  • 0 in reply to Luke
    Guru 18595 points

    ProjectZero example

    v6.20

    I could switch to v7.10 but I do not think there is any change in connection establishment quality between these versions, is there?

    Have a good weekend!

  • 0 in reply to kazola
    TI__Guru** 101450 points

    Hi,

    Thank you for reaching out. I would recommend reviewing the following app note https://www.ti.com/lit/swra499

    The answers below assume you have configured the CC26x2r as peripheral.

    1- Assuming the calibration of the clock is correct, the probability of successful connection should be the same.

    2- Yes, the current consumption is affected. As the clock is less accurate, the Rx operations are slightly longer. Chapter §4.1 of https://www.ti.com/lit/swra499 provides some data.

    3- You can use SysConfig to change the LF clock source (and use the RCOSC as LF clock source).

    Using a clock "Derived from HF XOSC" will provide a very accurate LF clock, but prevent the device to go to low power mode (i.e. significant impact on the total power consumption).

    4- The probability of a forming a connection should not depend on the update parameter request approval policy. Keep in mind that offering other devices full control on the connection parameters may lead to uncontrolled power consumption, latency and throughput.

    If you are trying to debug connection issues, I recommend the following:

    1. Check the available air time - i.e. ensure the device has the air time to answer a connection request. To do so, you can use the RF observables.
    2. Ensure the LF clock accuracy matches the SCA (Sleep Clock Accuracy) set in the Bluetooth stack
    3. Ensure the RF performances of the design are correct (you can request a design review here: https://www.ti.com/tool/SIMPLELINK-2-4GHZ-DESIGN-REVIEWS) 

    I hope this will help,

    Best regards,

  • 0 in reply to Clément
    Guru 18595 points

    Thanks Clement,

    1) I intend on keeping that calibration routine the project_zero contains so I should be OK there, am I right?

    2) OK

    3) in my example, this is greyed out, says "sysconfig cannot be used for this example"

    4) OK, I don't need to check all this, since the board works most of the time. With laptops, PWA... just raspberry pi sometimes is a bit tricky to make it connect.

    Please tell me what you think about the remaining points above and we will close this thread.

    Thanks

  • +1 in reply to kazola
    TI__Guru** 101450 points

    Hi,

    1) You should ensure the symbol USE_RCOSC is defined in your project. This can be done using SysConfig > BLE > Advanced Settings > Use RCOSC. This will then ensure the proper calibration and SCA are set (if you are curious look for the "USE_RCOSC" symbols inside project_zero.c).
    Note that you will probably receive a benign warning message (see #3 for steps to solve it).

    3) True, as the project_zero is an OAD-enabled project, the CCFG is held by the BIM project. In the BIM project, the configuration should be made per the description provided in my previous message.

    I hope this will help,

    Best regards,