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Configure external clock 32.768K

Hi

Please advise how to configure external clock instead using the internal.

Thanks

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  • Hi Josh

    Yes, you can. It's important that the clock applies a rail-to-rail clock signal. Please read more on how to configure the 32.768 kHz oscillator here

    Best regards,

    Simon

  • Hi,

    I need to configure the SDK SoftDevice clock configuration to work with external Oscillator (square wave).

    At the SDK below you can see just three "NRF_CLOCK" options to choose from and there is not LFXO rail to rail like you suggest.

    Please advise.

    Thanks

    // <h> Clock - SoftDevice clock configuration

     

    //==========================================================

    // <o> NRF_SDH_CLOCK_LF_SRC  - SoftDevice clock source.

     

    // <0=> NRF_CLOCK_LF_SRC_RC 

    // <1=> NRF_CLOCK_LF_SRC_XTAL 

    // <2=> NRF_CLOCK_LF_SRC_SYNTH 

     

    #ifndef NRF_SDH_CLOCK_LF_SRC

    #define NRF_SDH_CLOCK_LF_SRC 0

    #endif

     

    // <o> NRF_SDH_CLOCK_LF_RC_CTIV - SoftDevice calibration timer interval. 

    #ifndef NRF_SDH_CLOCK_LF_RC_CTIV

    #define NRF_SDH_CLOCK_LF_RC_CTIV 16 //0

    #endif

     

    // <o> NRF_SDH_CLOCK_LF_RC_TEMP_CTIV - SoftDevice calibration timer interval under constant temperature. 

    // <i> How often (in number of calibration intervals) the RC oscillator shall be calibrated

    // <i>  if the temperature has not changed.

     

    #ifndef NRF_SDH_CLOCK_LF_RC_TEMP_CTIV

    #define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2   //0

    #endif

     

    // <o> NRF_SDH_CLOCK_LF_ACCURACY  - External clock accuracy used in the LL to compute timing.

     

    // <0=> NRF_CLOCK_LF_ACCURACY_250_PPM 

    // <1=> NRF_CLOCK_LF_ACCURACY_500_PPM 

    // <2=> NRF_CLOCK_LF_ACCURACY_150_PPM 

    // <3=> NRF_CLOCK_LF_ACCURACY_100_PPM 

    // <4=> NRF_CLOCK_LF_ACCURACY_75_PPM 

    // <5=> NRF_CLOCK_LF_ACCURACY_50_PPM 

    // <6=> NRF_CLOCK_LF_ACCURACY_30_PPM 

    // <7=> NRF_CLOCK_LF_ACCURACY_20_PPM 

    // <8=> NRF_CLOCK_LF_ACCURACY_10_PPM 

    // <9=> NRF_CLOCK_LF_ACCURACY_5_PPM 

    // <10=> NRF_CLOCK_LF_ACCURACY_2_PPM 

    // <11=> NRF_CLOCK_LF_ACCURACY_1_PPM 

     

    #ifndef NRF_SDH_CLOCK_LF_ACCURACY

    #define NRF_SDH_CLOCK_LF_ACCURACY 1  //7

    #endif

Reply
  • Hi,

    I need to configure the SDK SoftDevice clock configuration to work with external Oscillator (square wave).

    At the SDK below you can see just three "NRF_CLOCK" options to choose from and there is not LFXO rail to rail like you suggest.

    Please advise.

    Thanks

    // <h> Clock - SoftDevice clock configuration

     

    //==========================================================

    // <o> NRF_SDH_CLOCK_LF_SRC  - SoftDevice clock source.

     

    // <0=> NRF_CLOCK_LF_SRC_RC 

    // <1=> NRF_CLOCK_LF_SRC_XTAL 

    // <2=> NRF_CLOCK_LF_SRC_SYNTH 

     

    #ifndef NRF_SDH_CLOCK_LF_SRC

    #define NRF_SDH_CLOCK_LF_SRC 0

    #endif

     

    // <o> NRF_SDH_CLOCK_LF_RC_CTIV - SoftDevice calibration timer interval. 

    #ifndef NRF_SDH_CLOCK_LF_RC_CTIV

    #define NRF_SDH_CLOCK_LF_RC_CTIV 16 //0

    #endif

     

    // <o> NRF_SDH_CLOCK_LF_RC_TEMP_CTIV - SoftDevice calibration timer interval under constant temperature. 

    // <i> How often (in number of calibration intervals) the RC oscillator shall be calibrated

    // <i>  if the temperature has not changed.

     

    #ifndef NRF_SDH_CLOCK_LF_RC_TEMP_CTIV

    #define NRF_SDH_CLOCK_LF_RC_TEMP_CTIV 2   //0

    #endif

     

    // <o> NRF_SDH_CLOCK_LF_ACCURACY  - External clock accuracy used in the LL to compute timing.

     

    // <0=> NRF_CLOCK_LF_ACCURACY_250_PPM 

    // <1=> NRF_CLOCK_LF_ACCURACY_500_PPM 

    // <2=> NRF_CLOCK_LF_ACCURACY_150_PPM 

    // <3=> NRF_CLOCK_LF_ACCURACY_100_PPM 

    // <4=> NRF_CLOCK_LF_ACCURACY_75_PPM 

    // <5=> NRF_CLOCK_LF_ACCURACY_50_PPM 

    // <6=> NRF_CLOCK_LF_ACCURACY_30_PPM 

    // <7=> NRF_CLOCK_LF_ACCURACY_20_PPM 

    // <8=> NRF_CLOCK_LF_ACCURACY_10_PPM 

    // <9=> NRF_CLOCK_LF_ACCURACY_5_PPM 

    // <10=> NRF_CLOCK_LF_ACCURACY_2_PPM 

    // <11=> NRF_CLOCK_LF_ACCURACY_1_PPM 

     

    #ifndef NRF_SDH_CLOCK_LF_ACCURACY

    #define NRF_SDH_CLOCK_LF_ACCURACY 1  //7

    #endif

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