How to Select External XTAL Oscillator for SoftDevice Use (nRF51)

[Musa]

I am having issues using the correct definition for the clock config: for nrf_clock_lf_cfg_t clock_lf_cfg = NRF_CLOCK_LFCLKSRC; SOFTDEVICE_HANDLER_INIT(&clock_lf_cfg, NULL); I am using:

#define NRF_CLOCK_LFCLKSRC  {	.source        	= NRF_CLOCK_LF_SRC_XTAL,\
														.rc_ctiv 				= 0, 									\
														.rc_temp_ctiv 	= 0, 									\
														.xtal_accuracy 	= NRF_CLOCK_LF_XTAL_ACCURACY_20_PPM}

And as other devs have reported, it just hangs. However, I actually have an xtal on the board: , so I don't understand why this does not work. Using both NRF_CLOCK_LF_SRC_RC, and NRF_CLOCK_LF_SRC_SYNTH both work, but may be causing issues with my SPI slave device.

What's going on and how can I fix?

I am using SDK11.0 with nRF51422-QFN

cheers.

[RK]

Your schematic shows a 16MHz crystal, it doesn't show a 32.768kHz crystal however. That's the LF crystal the clock source refers to. Do you have that?

[Musa]

Thanks for the answer. I understand now - I read the documentation (Software Development Kit > nRF5 SDK > nRF5 SDK v11.0.0 > Hardware Drivers > Clock) and that cleared it up. I thought you define both the HF and LF clock. Thank you.