RTC prescaller SDK17

[pawel]

Hi All,

Is macro in /modules/nrfx/hal/nrf_rtc.h correct?

/** @brief Macro for converting expected frequency to prescaler setting. */

#define RTC_FREQ_TO_PRESCALER(FREQ) (uint16_t)(((RTC_INPUT_FREQ) / (FREQ)) - 1)

so for 1000Hz requested it returns 31 which gives 1024Hz but better value is 32 with 992Hz.

It is a typical problem with c rounding down.

Regards,

Pawel

[Priyanka]

Hi pawel,

Thank you very much for reporting this to us . This helps us in further improvement. I have alerted this internally and we are onto it.

Best Regards,

Priyanka

[pawel]

Thank you,

I found correct version in freertos ports, also in SDK

/* Constants required to manipulate the NVIC. */
#define portNRF_RTC_PRESCALER ( (uint32_t) (ROUNDED_DIV(configSYSTICK_CLOCK_HZ, configTICK_RATE_HZ) - 1) )