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AWR2944: Question on AWR_PHASE_SHIFTER_CAL_DATA_SAVE_SB(rlRfPhShiftCalibDataStore)

Chris Meng
Mastermind 37646 points
Part Number: AWR2944
Other Parts Discussed in Thread: AWR2243

Hi,

In mmwave_dfp_02_04_09_01\docs\mmWave-Radar-Interface-Control.pdf, I found below info.

5.3.3 Sub block 0x00AC – AWR_PHASE_SHIFTER_CAL_DATA_SAVE_SB

Does it mean user will get same values by AWR_PHASE_SHIFTER_CAL_DATA_SAVE_SB (rlRfPhShiftCalibDataStore) on different AWR2944 devices?

If yes, how to know if the rfinit/run-time TX phase shifter calibration works or not? Any way to know the real TX phase shifter calibration setting on AWR2944? Or checking the phase result from ADC data after phaseshifter calibration vs no phaseshifter calibration?

Thanks,

Chris

  • 0
    TI__Mastermind 29805 points

    Hello Chris,

    On AWR294x there is no active phase shifter calibration. It is a single fixed LUT used for all devices. Therefor, there is no 'passing' or 'failing' of the calibration, it is simply referencing a fixed LUT.

    Regards,

    Adrian

  • 0 in reply to aozer
    TI__Mastermind 37646 points

    Adrian,

    AWR2944 supports run-time TX phase shifter calibration. Is this an active calibration?

    Thanks,

    Chris

  • 0 in reply to Chris Meng
    TI__Mastermind 29805 points

    Hello,

    Runtime is also not an active calibration. On AWR2944 there is no active phase shifter calibration, it is all done based on LUT calculations.

    Regards,

    Adrian

  • 0 in reply to aozer
    TI__Mastermind 37646 points

    Adrain,

    For AWR2243 phase shifter calibration, we use a TX phase shifter error + LUT for TX Phase Shifter Temperature Drift Mitigation.

    I am confused on the fix LUT for AWR2944 phase shifter calibration. How this fix LUT to meet difference phase shifter error in different AWR2944 devices? What's the right flow for phase shifter calibration on AWR2944?

    Thanks,

    Chris 

  • 0 in reply to Chris Meng
    TI__Mastermind 29805 points

    Hello,

    In our testing there has been no reduction in accuracy compared to the loopback calibrations of other devices. From a customer perspective, the process should be the same to compensate for PCB routing imbalances and device processes during the factory calibration. 

    Regards,

    Adrian

  • 0 in reply to aozer
    TI__Mastermind 37646 points

    Adrian,

    Below is the Phase shifter calibration flow for AWR2944 I found out based on the info in the app note Cascade Coherency and Phase Shifter Calibration. Would you help to check if anything is missed and help on the question?

    1. Get the phase shift error for AWR2944. This error is different with different AWR2944 device/board.

    2. Restore phase shift error got from #1 using AWR_PHASE_SHIFTER_CAL_DATA_RESTORE_SB to AWR2944

    3. Update phase shifter setting if there is temperature change. In this step, we need TX Phase Shift Calibration Temperature Correction LUT for AWR2944. When I tried to find the LUT for AWR2944, I found below post which refers to TX Phase Shifter Run Time Calibration. But based on above discussion with you, it seems the TX Phase Shifter Run Time Calibration is used a fixed LUT. 

    https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1259683/awr2944-phase-shifter-temperature-correction-lut

    Can you share the TX Phase Shift Calibration Temperature Correction LUT for AWR2944? Then customer can update phase shifter error+ temp correction LUT to the AWR2944 device.

    Thanks,

    Chris

  • 0 in reply to Chris Meng
    TI__Mastermind 29805 points

    Hello,

    For temperature correction during factory calibration, the user can trigger a one-time calibration using the runtime calibration API and force the temperature index of the phase shifter calibration using the CAL_TEMP_INDEX_OVERRIDE_ENABLE bit for the TX phase shifter override. For example, they can force the temp index to -40C, 25C, 85C, and 130C (or whatever interval is desired by the customer) and compute the offsets. Then in the field based on the device operating temperature then can again force the same temp indexes by using one-time calibration with temp index override to ensure the same LUT codes are applied.

    Regards,

    Adrian 

  • 0 in reply to aozer
    TI__Mastermind 37646 points

    Adrain,

    Thanks for your reply.

    aozer said:
    For example, they can force the temp index to -40C, 25C, 85C, and 130C (or whatever interval is desired by the customer) and compute the offsets.

    The tests are at 25C with different temp index, right?

    The offset here means the phase shifter error user gets by below way with different temp index?

    aozer said:
    Then in the field based on the device operating temperature then can again force the same temp indexes by using one-time calibration with temp index override to ensure the same LUT codes are applied.

    Does the "same LUT code" mean the phase shifter error got by different temp index?

    Thanks,

    Chris

  • 0 in reply to Chris Meng
    TI__Mastermind 29805 points

    Hello,

    Yes, your understanding on all points is correct.

    Regards,

    Adrian