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CC2642R: boosterpack attenna switch speed

shark gao1
Prodigy 120 points
Part Number: CC2642R

hi,

I use sdk4.40.04.04, connectionless aoa function on master device.

TI document always suggest us to use 2us time slot sampling, because boosterpack's switch time is 1.6us, I checked SKY's datasheet, it is 150ns. So where does the 1.6us come from?

I checked RTLSSrv_initAntArray() in rtls_svr.c, but can not find somewhere controlling the pins. So I can not analyze the total switching time.

Even if I replaced with high performance switchers, I still can not shorten the total time if it is mainly consumed by software code.

  • 0
    TI__Guru**** 168297 points

    Hi,

    Thanks for your inquiry. I notified a colleague and he will reply as soon as possible.

    To be confirmed, but this timing may be set to account for the more conservative switch shown at Table 1 of the AoA boosterpack design document. 

    https://www.ti.com/lit/an/tida029/tida029.pdf

    Regards,

    Rafael

  • 0
    TI__Guru* 94028 points

    Hi,

    Could you point me to the document stating the antenna switch and settle is 1.6us? I guess this value is not correct. Actually, the switching and settling time of the antennas should be below 0.125us when using 1us slots and below 1.125us when using 2us slots (please consult §2.2 of this app note for details).

    As you mentioned, the settling time of the RF switches is 150ns - i.e. slightly over the 125ns mentioned earlier.  As a result we suggest to use 2us sampling slots. I know other users are using 1us sampling slots anyway, but, again, this is not what we recommend.

    To finish, our SimpleLink Academy labs (see Task 5) provides a way to measure antennae time.

    Best regards,

  • 0 in reply to Clément
    Prodigy 120 points

    Hi

    In the document in installed sdk:

    file:///C:/ti/simplelink_cc13x2_26x2_sdk_4_40_04_04/docs/ble5stack/ble_user_guide/html/ble-stack-5.x-guide/localization-index-cc13x2_26x2.html

    Configurations Supported

    * Sampling slot of 1us is supported by the AoA driver but some limitations exist when using the BOOSTXL-AOA hardware. The antennas of the BOOSTXL-AOA require 1.6 us to switch and settle (leaving 0.4 us in the sampling period to collect data). Other designs with faster RF switches can support 1us switching.

  • 0 in reply to shark gao1
    TI__Guru* 94028 points

    Hi,

    Thank you for pointing me to this document. I had to consult our R&D team to clear that out.

    1.6us is the switching and settling time you would measure with the process described at task 5 of our SimpleLink Academy labs. As the radio is sampling the CTE at 4 MHz, 0.4 us is enough to extract a sample at each sampling slot - as required by the Bluetooth specifications. 

    I confirm the switching time of the RF switches is 150ns. This switching time does not include the settling time that will depend of the antennas design and of the RF switches.

    Regards,

  • 0 in reply to Clément
    Prodigy 120 points

    hi

    I have studied aoa spec and aoa.c for n times, especially the function AOA_getPairAngles(), but still unknow how antennas are switched and the order of iq data storage. The lab example is based on hidden algorithm  or angle from mcu, and the result is not perfect.

    I am preparing debug functions to inspect data further on connectionless master device, and found that, the mcu often hung when SysCtrlSystemReset(), and __exit after RTLSCtrl_CLAoaEnableCmd(). This maybe the reason why rtls_ui visual tool often failed and need to reset the device and try again.

    thanks for your support.