stm32f1 periph_rtc implementation gets a 1s resolution by dividing CLOCK_LSx by 32768. This only make sense if CLOCK_LSE is set, otherwise CLOCK_LSI=~40000, which will lead to an imprecise rtc.
stm32f1 periph_rtc implementation gets a 1s resolution by dividing CLOCK_LSx by 32768. This only make sense if CLOCK_LSE is set, otherwise CLOCK_LSI=~40000, which will lead to an imprecise rtc.