Choice of RC Internal Oscillator on NRF52

[stefP]

Dear All,

We work on the NRF52 CSP revB. We have a board with two external crystals (32MhZ and 32kHz). When we use the example program with BLE and UART, it works great without any issue !

The issue is the following :

We want to work without 32KhZ Crystal. So we desold the crystal on the breadboard. Then in nrf_drv_config we make the following change

#define CLOCK_CONFIG_LF_SRC             NRF_CLOCK_LF_SRC_RC

We add to the project the driver nrf_drv_clock and in the main function, after the start of softdevice, BLE stacks.. we put the following functions

ret_code_t err = nrf_drv_clock_init(p_config); nrf_drv_clock_lfclk_request(); nrf_drv_clock_calibration_force ();

The err is NRF_SUCCESS and nrf_drv_clock_lfclk_is_running() is true !!

But the Bluetooth protocol doesn't work ! I have the feeling that the RC internal Oscillator is not selected ! Can you help us ? How to check that the internal RC Oscillator is choosen ?

Sincerely yours

[Ole Bauck]

You need to change

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, NULL)

to for example

SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_RC_250_PPM_4000MS_CALIBRATION, NULL)

[stefP]

Thank you for all. It works !