NRF51422 on Custom board

[Martin]

Hi

we have a custom board, where the clock does not start (verified by osciloscope). We do not use an external clock, so from our understanding the command to init the S130 soft device should be changed from

SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL);

to

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_SYNTH_250_PPM, false);

or

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_RC_250_PPM_250MS_CALIBRATION, false);

Is this understanding correct?

Any hints are appreciated.

[Ole Bauck]

You have to change clock_lf_cfg to for example:

//internal clock configuration
	nrf_clock_lf_cfg_t rc_clock_lf_cfg = {.source = NRF_CLOCK_LF_SRC_RC, \
										.rc_ctiv = 1, \
										.rc_temp_ctiv = 1};
	//synth clock configuration
	nrf_clock_lf_cfg_t synth_clock_lf_cfg = {.source = NRF_CLOCK_LF_SRC_SYNTH, \
											.rc_ctiv = 0, \
											.rc_temp_ctiv = 0, \
											.xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM};

See here for a description of the data fields. We do not recommend using synthesized clock as this draws considerably more power than using RC clock.