Using LF RC OSC with +/-250ppm

[swlnk]

In my design, I am using a module based on the NRF52832, with a specified LF clock accuracy of +/-250ppm. In my application, I am using v15.0.0 of the SDK with SoftDevice S132 v6.0.0. In the file nrf_sdh.c, I can see the following code:

#if (   (NRF_SDH_CLOCK_LF_SRC      == NRF_CLOCK_LF_SRC_RC)          \
     && (NRF_SDH_CLOCK_LF_ACCURACY != NRF_CLOCK_LF_ACCURACY_500_PPM))
    #warning Please select NRF_CLOCK_LF_ACCURACY_500_PPM when using NRF_CLOCK_LF_SRC_RC
#endif

Why can I not set the accuracy to NRF_CLOCK_LF_ACCURACY_250_PPM? If I use NRF_CLOCK_LF_ACCURACY_500_PPM I will get worse power consumption. Is this some restriction of the hardware that forces this?

Thanks.

[Stian Røed Hafskjold]

The accuracy of the LFRC clock is not good enough for 250ppm. Please see this errata: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.Rev2.errata/dita/errata/nRF52832/Rev2/latest/anomaly_832_146.html?cp=2_1_1_0_1_38