21.8.1.2.1 Code

Copy-paste the following code to your user application:

/* Configure the external 32KHz oscillator */
configure_extosc32k();

/* Enable the external 32KHz oscillator */
enum status_code osc32k_status =
        system_clock_source_enable(SYSTEM_CLOCK_SOURCE_XOSC32K);

if (osc32k_status != STATUS_OK) {
    /* Error enabling the clock source */
}

#if (!SAMC21)
    /* Configure the DFLL in open loop mode using default values */
configure_dfll_open_loop();

/* Enable the DFLL oscillator */
enum status_code dfll_status =
        system_clock_source_enable(SYSTEM_CLOCK_SOURCE_DFLL);

if (dfll_status != STATUS_OK) {
    /* Error enabling the clock source */
}

/* Configure flash wait states before switching to high frequency clock */
system_flash_set_waitstates(2);

/* Change system clock to DFLL */
struct system_gclk_gen_config config_gclock_gen;
system_gclk_gen_get_config_defaults(&config_gclock_gen);
config_gclock_gen.source_clock    = SYSTEM_CLOCK_SOURCE_DFLL;
config_gclock_gen.division_factor = 1;
system_gclk_gen_set_config(GCLK_GENERATOR_0, &config_gclock_gen);
#endif