Enum sam4l::pm::SystemClockSource

pub enum SystemClockSource {
    RcsysAt115kHz,
    DfllRc32kAt48MHz,
    ExternalOscillator {
        frequency: OscillatorFrequency,
        startup_mode: OscillatorStartup,
    },
    PllExternalOscillatorAt48MHz {
        frequency: OscillatorFrequency,
        startup_mode: OscillatorStartup,
    },
}

Which source the system clock should be generated from. These are specified as system clock source appended with the clock that it is sourced from appended with the final frequency of the system. So for example, one option is to use the DFLL sourced from the RC32K with a final frequency of 48 MHz.

When new options (either sources or final frequencies) are needed, they should be added to this list, and then the setup_system_clock function can be modified to support it. This is necessary because configurations must be changed not just with the input source but also based on the desired final frequency.

For options utilizing an external oscillator, the configurations for that oscillator must also be provided.

Variants

RcsysAt115kHz

Use the RCSYS clock (which the system starts up on anyways). Final system frequency will be 115 kHz. Note that while this is the default, Tock is NOT guaranteed to work on this setting and will likely fail.

DfllRc32kAt48MHz

Use the internal digital frequency locked loop (DFLL) sourced from the internal RC32K clock. Note this typically requires calibration of the RC32K to have a consistent clock. Final frequency of 48 MHz.

ExternalOscillator

Use an external crystal oscillator as the direct source for the system clock. The final system frequency will match the frequency of the external oscillator.

Fields of ExternalOscillator

frequency: OscillatorFrequency
startup_mode: OscillatorStartup

PllExternalOscillatorAt48MHz

Use an external crystal oscillator as the input to the internal phase locked loop (PLL) for the system clock. This results in a final frequency of 48 MHz.

Fields of PllExternalOscillatorAt48MHz

frequency: OscillatorFrequency
startup_mode: OscillatorStartup

Trait Implementations

impl Copy for SystemClockSource

impl Clone for SystemClockSource

fn clone(&self) -> SystemClockSource

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SystemClockSource

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.