BLE_Nano nRF51 Central heart rate
nrf_clock_lf_cfg_t Struct Reference
[Types]
Type representing lfclk oscillator source. More...
#include <nrf_sdm.h>
Data Fields | |
uint8_t | source |
LF oscillator clock source, see Possible lfclk oscillator sources @{. | |
uint8_t | rc_ctiv |
Only for NRF_CLOCK_LF_SRC_RC: Calibration timer interval in 1/4 second units (nRF51: 1-64, nRF52: 1-32). | |
uint8_t | rc_temp_ctiv |
Only for NRF_CLOCK_LF_SRC_RC: How often (in number of calibration intervals) the RC oscillator shall be calibrated if the temperature hasn't changed. | |
uint8_t | xtal_accuracy |
External crystal clock accuracy used in the LL to compute timing windows. |
Detailed Description
Type representing lfclk oscillator source.
Definition at line 147 of file nrf_sdm.h.
Field Documentation
uint8_t rc_ctiv |
Only for NRF_CLOCK_LF_SRC_RC: Calibration timer interval in 1/4 second units (nRF51: 1-64, nRF52: 1-32).
- Note:
- To avoid excessive clock drift, 0.5 degrees Celsius is the maximum temperature change allowed in one calibration timer interval. The interval should be selected to ensure this.
- Must be 0 if source is not NRF_CLOCK_LF_SRC_RC.
uint8_t rc_temp_ctiv |
Only for NRF_CLOCK_LF_SRC_RC: How often (in number of calibration intervals) the RC oscillator shall be calibrated if the temperature hasn't changed.
0: Always calibrate even if the temperature hasn't changed. 1: Only calibrate if the temperature has changed (nRF51 only). 2-33: Check the temperature and only calibrate if it has changed, however calibration will take place every rc_temp_ctiv intervals in any case.
- Note:
- 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 +/-250ppm 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.
uint8_t source |
LF oscillator clock source, see Possible lfclk oscillator sources @{.
uint8_t xtal_accuracy |
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