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CC2340R5: CC2340 Dynamic Adjustment Capacitance Matrix

wangrenli
Intellectual 690 points
Part Number: CC2340R5

HI,

Can the CC2340 change the crystal compensation values Q1 and Q2 while the code is running. e.g. I want to adjust the capacitor matrix according to the current temperature. I see that there are calls to CKMDSetTargetCapTrim and CKMDSetInitialCapTrim during power up initialization, but I am not sure if I can adjust them dynamically after running.

The reason is that when the capacitor matrix is used with a fixed value, there is a big difference in frequency deviation between high temperature and room temperature, and there is no way to dynamically adjust it according to the current temperature.

  • 0
    TI__Genius 15535 points

    Hello Wangrenli,

    Thanks for reaching out. The device automatically enables temperature compensation.

    You can take a look at the following section of the User`s Guide: RF Temperature Compensation.

    BR,

    David.

  • 0 in reply to David
    Intellectual 690 points

    HI,

    I use the default temperature compensation and configure Q1 and Q2, the frequency deviation is about 40k at room temperature, but at high temperature the frequency deviation is 140k at maximum, at high temperature the frequency deviation is close to the critical value, is it related to P0~P3, how to adjust P0~P3 according to the parameters of the crystal.

  • +1 in reply to wangrenli
    TI__Genius 15535 points

    Hello,

    Generally it is not recommended to change Q1 and Q2 dynamically. A possibility is to refer to the polynomial function of the crystal (given by the vendor) and apply it in RF compensation, which should already be an improvement. The considerable difference in frequency deviation due to temperature may be from not having the same crystal polynomial values as the default ones given.

    Please take a look at the following section of our User`s Guide for more information on RF Temperature Compensation.

    BR,

    David.