What are unit of NRF_SDH_CLOCK_LF_RC_CTIV

Question

In file sdk_config.h, in order to configure a calibration interval of 8 seconds, what number should be used in the define NRF_SDH_CLOCK_LF_RC_CTIV? 
 The time units are not provided.

Jared · Accepted Answer

Hi 
 Chapter 19.3.9 in the product specification specifies the calibration timer interval in multiple of 0.25 seconds. From the documentation : "Must be 0 if source is not NRF_CLOCK_LF_SRC_RC .For nRF52, the application must ensure calibration at least once every 8 seconds to ensure +/-500 ppm clock stability. The recommended configuration for NRF_CLOCK_LF_SRC_RC on nRF52 is rc_ctiv=16 and rc_temp_ctiv=2. This will ensure calibration at least once every 8 seconds and for temperature changes of 0.5 degrees Celsius every 4 seconds. See the Product Specification for the nRF52 device being used for more information." 
 Best Regards 
 Jared

What are unit of NRF_SDH_CLOCK_LF_RC_CTIV

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