Hi,Master:
Platform: 52840
Protocol stack: S14
Problem:
Three sources for LFCK
• 32.768 kHz RC oscillator (LFRC)
• 32.768 kHz crystal oscillator (LFXO)
• 32.768 kHz synthesized from HFCLK (LFSYNT)
1. Which is the highest precision and how much higher? (If used for time counting, what is the error of the day with the lowest accuracy? What is the highest accuracy?)
2. Which power consumption is the largest and how much? Which power consumption is the lowest and how much power is there?
3.rc_ctiv/rc_temp_ctiv/accuracy How much different values of each field affect power consumption?
typedef struct
{
uint8_t source; /**< LF oscillator clock source, see @ref NRF_CLOCK_LF_SRC. */
uint8_t rc_ctiv; /**< Only for ::NRF_CLOCK_LF_SRC_RC: Calibration timer interval in 1/4 second
units (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.
@note 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 (legacy - 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.
@note 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.*/
uint8_t accuracy; /**< External clock accuracy used in the LL to compute timing
windows, see @ref NRF_CLOCK_LF_ACCURACY.*/
} nrf_clock_lf_cfg_t;
/**@defgroup NRF_CLOCK_LF_ACCURACY Clock accuracy
* @{ */
#define NRF_CLOCK_LF_ACCURACY_250_PPM (0) /**< Default: 250 ppm */
#define NRF_CLOCK_LF_ACCURACY_500_PPM (1) /**< 500 ppm */
#define NRF_CLOCK_LF_ACCURACY_150_PPM (2) /**< 150 ppm */
#define NRF_CLOCK_LF_ACCURACY_100_PPM (3) /**< 100 ppm */
#define NRF_CLOCK_LF_ACCURACY_75_PPM (4) /**< 75 ppm */
#define NRF_CLOCK_LF_ACCURACY_50_PPM (5) /**< 50 ppm */
#define NRF_CLOCK_LF_ACCURACY_30_PPM (6) /**< 30 ppm */
#define NRF_CLOCK_LF_ACCURACY_20_PPM (7) /**< 20 ppm */
#define NRF_CLOCK_LF_ACCURACY_10_PPM (8) /**< 10 ppm */
#define NRF_CLOCK_LF_ACCURACY_5_PPM (9) /**< 5 ppm */
#define NRF_CLOCK_LF_ACCURACY_2_PPM (10) /**< 2 ppm */
#define NRF_CLOCK_LF_ACCURACY_1_PPM (11) /**< 1 ppm */
thanks!
