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CC2652RB: Cap-Array Delta adjustment for each board

Part Number: CC2652RB
Other Parts Discussed in Thread: CC2652R

Hi Experts,

A customer would like to adjust the XOSC_HF frequency for each their board by change the value of Cap-Array Delta.
It seems that Cap-Array Delta can be modified following the thread below.

However, it requires to modify the CCFG.c. 
Am I correct?

The customer would like to modify the Cap-Array Delta at the production line some how.
For example, CC2652RB is running like a maintenance mode and communicating with PC by SPI, UART, BLE, etc.
The command is prepared to change the Cap-Array Delta.

The procedure is as follows:
1. Continuous Tx at specified ch.
2. Freq. is measured.
3. Cap-Array Delta is modified.
4. Repeat from 1 to 3 and then the data is saved onto Flash.
5. Read the value by a prepared command.
6. Start running with the value at 4.

Could you please let us know whether it can be modified during it is running or not?
Also, could you please let us know if the value of Cap-Array Delta on flash can not be written with JTAG connection?

Thank you so much in advance for your advice.
Best regards,
Hitoshi 

  • Hitoshi, 

    CC2652RB has an internal oscillator, so it is not possible to adjust the cap array to change the frequency. This is only possible on non-BAW devices. 

    The procedure should be as follows:

    1. Adjust cap array.
    2. Turn on OSC_HF and transmit a CW with the radio to measure the frequency. 
    3. Turn off OSC_HF
    4. Wait 5 ms for the oscillator circuitry to stop.

    Redo step 1-4 until the output frequency is tuned to the frequency you want it to be. When you then know the cap-array delta value, you can write it to the CCFG.By using Flash Programmer 2 you can update the CCFG only if you want. 

    -Simon 

  • Hi Simon,

    Thank you for correcting me.
    First of all, I will inform that it is not possible to adjust the cap array with CC2652RB.

    Second, I think that I could recommend CC2652R instead.
    I have checked the TRM  but it is the same for CC2652R and CC2652RB.

    XOSC_CAPARRAY_DELTA in MODE_CONF Register is read only register.
    So, it seems it is only way to modify the CCFG.C. 

    Could you please let me know "Adjust cap array" method with CC2652R?
    Thank you in advance for your kind support.

    Best regards,
    Hitoshi

  • Hitoshi, 

    The method I described above is for any CC13xx/CC26xx device without BAW. 

    Note that the BAW oscillator used in CC2652RB is calibrated during production, so there is no need for users to do frequency tuning.

    -Simon

  • Hi Simon,

    Understood.
    I would go with CC2652R not RB.
    So, could you please let me know how to modify the Cap-array delta which is Read only register?
    Or do we have any register to change the capacitor for XOSC_HF?

    Thank you for your kind check.
    Best regards,
    Hitoshi

  • Hi Simon,

    I am sorry I made confusion.
    I think it is better to create another thread for CC2652R.
    I would like to close this thread.

    Thank you and best regards,
    Hitoshi