internal crystal settings

[pavan]

Hello All,

I am working on Raytac module based on nrf51822 with ble_app_uart code. I can see on module there is no external crystal , my module is not able advertise, i can see nothing in Nordic Uart APP. my clock setting are as below.

#ifdef S210
#define NRF_CLOCK_LFCLKSRC      NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION 
#else
#define NRF_CLOCK_LFCLKSRC      {.source        = NRF_CLOCK_LF_SRC_XTAL,            \
                                 .rc_ctiv       = 0,                                \
                                 .rc_temp_ctiv  = 0,                                \
                                 .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM} 

Now i want to use internal crystal please let me know what configuration i need to make to select internal oscilator.

Thanks in advance Pavan S K

[AmbystomaLabs]

Just so you understand, there is no "internal crystal". It is an internal RC oscillator. The oscillator is calibrated periodically against the 32MHz crystal. The calibration intervals and temp parameters are rc_ctiv and rc_temp_ctiv in below info. You will see an increase of about 8 uA (approx based on my memory) average current consumption between the RC circuit and the periodic calibration routine which uses the processor.