How to detect the external low-frequency vibration crystal work?When it doesn't work how to switch frequency crystals?

[juge90]

52832，SDK12.0.0

I met such a situation: In the use of JLink burning program or air upgrade, after the completion of the program card died in initialization low-frequency crystals.

"sd_softdevice_enable(p_clock_lf_cfg, softdevice_fault_handler);"

[bjorn-spockeli]

You need to modify the NRF_CLOCK_LFCLKSRC in the pca10040.h or custom_board.h to the following

#define NRF_CLOCK_LFCLKSRC      {.source        = NRF_CLOCK_LF_SRC_RC,            \

                                 .rc_ctiv       = 16,                             \

                                 .rc_temp_ctiv  = 2,                              \

                                 .xtal_accuracy = NRF_CLOCK_LF_XTAL_ACCURACY_250_PPM }

[juge90]

How to detect abnormal external low-frequency crystals, then automatically switch to the internal low-frequency crystals？

[juge90]

How to detect abnormal external low-frequency crystals, then automatically switch to the internal low-frequency crystals？

[bjorn-spockeli]

Why do you need to detect "abnormal external low-frequency crystals" ? I assume that you know which crystal that is on your pcb?

[bjorn-spockeli]

You can the trigger the TASKS_LFCLKSTART task and wait for the EVENTS_LFCLKSTARTED and/or read the LFCLKSTAT register. See this page in the NRF52832 PS.