//! [config_dfll] void configure_dfll_open_loop(void) { //! [config_dfll_config] struct system_clock_source_dfll_config config_dfll; //! [config_dfll_config] //! [config_dfll_get_defaults] system_clock_source_dfll_get_config_defaults(&config_dfll); //! [config_dfll_get_defaults] //! [config_dfll_set_config] system_clock_source_dfll_set_config(&config_dfll); //! [config_dfll_set_config] }
/** Configures and starts the DFLL in closed loop mode with the given reference * generator. * * \param[in] source_generator Reference generator to use for the DFLL */ static void init_dfll( const enum system_clock_source source_generator) { struct system_gclk_gen_config cpu_clock_conf; system_gclk_gen_get_config_defaults(&cpu_clock_conf); cpu_clock_conf.output_enable = ENABLE_CPU_CLOCK_OUT; /* Switch to OSC8M/OSC16M while the DFLL is being reconfigured */ #if SAML21 cpu_clock_conf.source_clock = SYSTEM_CLOCK_SOURCE_OSC16M; #else cpu_clock_conf.source_clock = SYSTEM_CLOCK_SOURCE_OSC8M; #endif system_gclk_gen_set_config(GCLK_GENERATOR_0, &cpu_clock_conf); /* Turn off DFLL before adjusting its configuration */ system_clock_source_disable(SYSTEM_CLOCK_SOURCE_DFLL); /* Configure DFLL reference clock, use raw register write to * force-configure the channel even if the currently selected generator * clock has failed */ #if SAML21 GCLK->PCHCTRL[SYSCTRL_GCLK_ID_DFLL48].reg = GCLK_PCHCTRL_GEN(source_generator); #else GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(SYSCTRL_GCLK_ID_DFLL48) | GCLK_CLKCTRL_GEN(source_generator); #endif system_gclk_chan_enable(SYSCTRL_GCLK_ID_DFLL48); /* Configure DFLL */ struct system_clock_source_dfll_config config_dfll; system_clock_source_dfll_get_config_defaults(&config_dfll); config_dfll.on_demand = false; config_dfll.loop_mode = SYSTEM_CLOCK_DFLL_LOOP_MODE_CLOSED; config_dfll.multiply_factor = (48000000UL / system_gclk_chan_get_hz(SYSCTRL_GCLK_ID_DFLL48)); system_clock_source_dfll_set_config(&config_dfll); /* Restart DFLL */ system_clock_source_enable(SYSTEM_CLOCK_SOURCE_DFLL); while (system_clock_source_is_ready(SYSTEM_CLOCK_SOURCE_DFLL) == false) { /* Wait for DFLL to be stable before switch back */ } /* Switch back to the DFLL as the CPU clock source */ cpu_clock_conf.source_clock = SYSTEM_CLOCK_SOURCE_DFLL; system_gclk_gen_set_config(GCLK_GENERATOR_0, &cpu_clock_conf); };