/* Function for starting the internal LFCLK XTAL oscillator. 
Note that when using a SoftDevice, LFCLK is always on. */
static ret_code_t clock_config(void)
/* Function for starting the internal LFCLK XTAL oscillator. 
Note that when using a SoftDevice, LFCLK is always on. */
static ret_code_t clock_config(void)
{
    ret_code_t err_code;
    err_code = nrf_drv_clock_init();
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    nrf_drv_clock_lfclk_request(NULL);
    return NRF_SUCCESS;
}