Struct Pwm

pub struct Pwm<'a> { /* private fields */ }

Main struct for controlling PWM peripheral

Implementations

impl<'a> Pwm<'a>

pub fn new() -> Self

Create a new Pwm struct

Note:

• This method must be called only once when setting up the kernel peripherals.
• This peripheral depends on the chip’s clocks.
• Also, if interrupts are required, then an interrupt handler must be set. Otherwise, all the interrupts will be ignored.

pub fn gpio_to_pwm_pin(&'a self, gpio: RPGpio) -> PwmPin<'a>

Map the GPIO to a PwmPin struct

The returned structure can be used to control the PWM pin.

See PwmPin

Trait Implementations

impl Pwm for Pwm<'_>

Implementation of the Hardware Interface Layer (HIL)

fn start( &self, pin: &Self::Pin, frequency_hz: usize, duty_cycle: usize, ) -> Result<(), ErrorCode>

Start a PWM pin

Start the given PWM pin with the given frequency and the given duty cycle. The actual values may vary due to rounding errors. For high precision duty cycles, the frequency should be set less than:

let threshold_freq = pwm_struct.get_maximum_frequency_hz() / pwm_struct.get_maximum_duty_cycle()

Errors

This method may fail in one of the following situations:

• selected frequency and duty cycle higher than the maximum possible values
• 100% duty cycle demand for low frequencies (close to or below threshold_freq)
• very low frequencies

Safety

It is safe to call multiples times this method with different values while the pin is running.

Note: the pin must be set as a PWM pin prior to calling this method.

fn stop(&self, pin: &Self::Pin) -> Result<(), ErrorCode>

Stop the given pin

Errors

This method may never fail.

Safety

It is safe to call this method multiple times on the same pin. If the pin is already stopped, then it does nothing.

fn get_maximum_frequency_hz(&self) -> usize

Return the maximum value of the frequency in Hz

Panics

This method will panic if the dependencies are not resolved.

fn get_maximum_duty_cycle(&self) -> usize

Return an opaque value representing 100% duty cycle

type Pin = RPGpio

The chip-dependent type of a PWM pin.