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embassy/embassy-nrf/src/pwm.rs

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//! Pulse Width Modulation (PWM) driver.
#![macro_use]
use core::sync::atomic::{compiler_fence, Ordering};
use embassy_hal_internal::{into_ref, PeripheralRef};
use crate::gpio::sealed::Pin as _;
use crate::gpio::{AnyPin, Pin as GpioPin, PselBits};
use crate::ppi::{Event, Task};
use crate::util::slice_in_ram_or;
use crate::{interrupt, pac, Peripheral};
/// SimplePwm is the traditional pwm interface you're probably used to, allowing
/// to simply set a duty cycle across up to four channels.
pub struct SimplePwm<'d, T: Instance> {
_peri: PeripheralRef<'d, T>,
duty: [u16; 4],
ch0: Option<PeripheralRef<'d, AnyPin>>,
ch1: Option<PeripheralRef<'d, AnyPin>>,
ch2: Option<PeripheralRef<'d, AnyPin>>,
ch3: Option<PeripheralRef<'d, AnyPin>>,
}
/// SequencePwm allows you to offload the updating of a sequence of duty cycles
/// to up to four channels, as well as repeat that sequence n times.
pub struct SequencePwm<'d, T: Instance> {
_peri: PeripheralRef<'d, T>,
ch0: Option<PeripheralRef<'d, AnyPin>>,
ch1: Option<PeripheralRef<'d, AnyPin>>,
ch2: Option<PeripheralRef<'d, AnyPin>>,
ch3: Option<PeripheralRef<'d, AnyPin>>,
}
/// PWM error
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
#[non_exhaustive]
pub enum Error {
/// Max Sequence size is 32767
SequenceTooLong,
/// Min Sequence count is 1
SequenceTimesAtLeastOne,
/// EasyDMA can only read from data memory, read only buffers in flash will fail.
BufferNotInRAM,
}
const MAX_SEQUENCE_LEN: usize = 32767;
impl<'d, T: Instance> SequencePwm<'d, T> {
/// Create a new 1-channel PWM
#[allow(unused_unsafe)]
pub fn new_1ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
config: Config,
) -> Result<Self, Error> {
into_ref!(ch0);
Self::new_inner(pwm, Some(ch0.map_into()), None, None, None, config)
}
/// Create a new 2-channel PWM
#[allow(unused_unsafe)]
pub fn new_2ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
ch1: impl Peripheral<P = impl GpioPin> + 'd,
config: Config,
) -> Result<Self, Error> {
into_ref!(ch0, ch1);
Self::new_inner(pwm, Some(ch0.map_into()), Some(ch1.map_into()), None, None, config)
}
/// Create a new 3-channel PWM
#[allow(unused_unsafe)]
pub fn new_3ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
ch1: impl Peripheral<P = impl GpioPin> + 'd,
ch2: impl Peripheral<P = impl GpioPin> + 'd,
config: Config,
) -> Result<Self, Error> {
into_ref!(ch0, ch1, ch2);
Self::new_inner(
pwm,
Some(ch0.map_into()),
Some(ch1.map_into()),
Some(ch2.map_into()),
None,
config,
)
}
/// Create a new 4-channel PWM
#[allow(unused_unsafe)]
pub fn new_4ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
ch1: impl Peripheral<P = impl GpioPin> + 'd,
ch2: impl Peripheral<P = impl GpioPin> + 'd,
ch3: impl Peripheral<P = impl GpioPin> + 'd,
config: Config,
) -> Result<Self, Error> {
into_ref!(ch0, ch1, ch2, ch3);
Self::new_inner(
pwm,
Some(ch0.map_into()),
Some(ch1.map_into()),
Some(ch2.map_into()),
Some(ch3.map_into()),
config,
)
}
fn new_inner(
_pwm: impl Peripheral<P = T> + 'd,
ch0: Option<PeripheralRef<'d, AnyPin>>,
ch1: Option<PeripheralRef<'d, AnyPin>>,
ch2: Option<PeripheralRef<'d, AnyPin>>,
ch3: Option<PeripheralRef<'d, AnyPin>>,
config: Config,
) -> Result<Self, Error> {
into_ref!(_pwm);
let r = T::regs();
if let Some(pin) = &ch0 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
if let Some(pin) = &ch1 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
if let Some(pin) = &ch2 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
if let Some(pin) = &ch3 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
// Disable all interrupts
r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
r.shorts.reset();
r.events_stopped.reset();
r.events_loopsdone.reset();
r.events_seqend[0].reset();
r.events_seqend[1].reset();
r.events_pwmperiodend.reset();
r.events_seqstarted[0].reset();
r.events_seqstarted[1].reset();
r.decoder.write(|w| {
w.load().bits(config.sequence_load as u8);
w.mode().refresh_count()
});
r.mode.write(|w| match config.counter_mode {
CounterMode::UpAndDown => w.updown().up_and_down(),
CounterMode::Up => w.updown().up(),
});
r.prescaler.write(|w| w.prescaler().bits(config.prescaler as u8));
r.countertop.write(|w| unsafe { w.countertop().bits(config.max_duty) });
Ok(Self {
_peri: _pwm,
ch0,
ch1,
ch2,
ch3,
})
}
/// Returns reference to `Stopped` event endpoint for PPI.
#[inline(always)]
pub fn event_stopped(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_stopped)
}
/// Returns reference to `LoopsDone` event endpoint for PPI.
#[inline(always)]
pub fn event_loops_done(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_loopsdone)
}
/// Returns reference to `PwmPeriodEnd` event endpoint for PPI.
#[inline(always)]
pub fn event_pwm_period_end(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_pwmperiodend)
}
/// Returns reference to `Seq0 End` event endpoint for PPI.
#[inline(always)]
pub fn event_seq_end(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_seqend[0])
}
/// Returns reference to `Seq1 End` event endpoint for PPI.
#[inline(always)]
pub fn event_seq1_end(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_seqend[1])
}
/// Returns reference to `Seq0 Started` event endpoint for PPI.
#[inline(always)]
pub fn event_seq0_started(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_seqstarted[0])
}
/// Returns reference to `Seq1 Started` event endpoint for PPI.
#[inline(always)]
pub fn event_seq1_started(&self) -> Event<'d> {
let r = T::regs();
Event::from_reg(&r.events_seqstarted[1])
}
/// Returns reference to `Seq0 Start` task endpoint for PPI.
/// # Safety
///
/// Interacting with the sequence while it runs puts it in an unknown state
#[inline(always)]
pub unsafe fn task_start_seq0(&self) -> Task<'d> {
let r = T::regs();
Task::from_reg(&r.tasks_seqstart[0])
}
/// Returns reference to `Seq1 Started` task endpoint for PPI.
/// # Safety
///
/// Interacting with the sequence while it runs puts it in an unknown state
#[inline(always)]
pub unsafe fn task_start_seq1(&self) -> Task<'d> {
let r = T::regs();
Task::from_reg(&r.tasks_seqstart[1])
}
/// Returns reference to `NextStep` task endpoint for PPI.
/// # Safety
///
/// Interacting with the sequence while it runs puts it in an unknown state
#[inline(always)]
pub unsafe fn task_next_step(&self) -> Task<'d> {
let r = T::regs();
Task::from_reg(&r.tasks_nextstep)
}
/// Returns reference to `Stop` task endpoint for PPI.
/// # Safety
///
/// Interacting with the sequence while it runs puts it in an unknown state
#[inline(always)]
pub unsafe fn task_stop(&self) -> Task<'d> {
let r = T::regs();
Task::from_reg(&r.tasks_stop)
}
}
impl<'a, T: Instance> Drop for SequencePwm<'a, T> {
fn drop(&mut self) {
let r = T::regs();
if let Some(pin) = &self.ch0 {
pin.set_low();
pin.conf().reset();
r.psel.out[0].reset();
}
if let Some(pin) = &self.ch1 {
pin.set_low();
pin.conf().reset();
r.psel.out[1].reset();
}
if let Some(pin) = &self.ch2 {
pin.set_low();
pin.conf().reset();
r.psel.out[2].reset();
}
if let Some(pin) = &self.ch3 {
pin.set_low();
pin.conf().reset();
r.psel.out[3].reset();
}
}
}
/// Configuration for the PWM as a whole.
#[non_exhaustive]
pub struct Config {
/// Selects up mode or up-and-down mode for the counter
pub counter_mode: CounterMode,
/// Top value to be compared against buffer values
pub max_duty: u16,
/// Configuration for PWM_CLK
pub prescaler: Prescaler,
/// How a sequence is read from RAM and is spread to the compare register
pub sequence_load: SequenceLoad,
}
impl Default for Config {
fn default() -> Config {
Config {
counter_mode: CounterMode::Up,
max_duty: 1000,
prescaler: Prescaler::Div16,
sequence_load: SequenceLoad::Common,
}
}
}
/// Configuration per sequence
#[non_exhaustive]
#[derive(Clone)]
pub struct SequenceConfig {
/// Number of PWM periods to delay between each sequence sample
pub refresh: u32,
/// Number of PWM periods after the sequence ends before starting the next sequence
pub end_delay: u32,
}
impl Default for SequenceConfig {
fn default() -> SequenceConfig {
SequenceConfig {
refresh: 0,
end_delay: 0,
}
}
}
/// A composition of a sequence buffer and its configuration.
#[non_exhaustive]
pub struct Sequence<'s> {
/// The words comprising the sequence. Must not exceed 32767 words.
pub words: &'s [u16],
/// Configuration associated with the sequence.
pub config: SequenceConfig,
}
impl<'s> Sequence<'s> {
/// Create a new `Sequence`
pub fn new(words: &'s [u16], config: SequenceConfig) -> Self {
Self { words, config }
}
}
/// A single sequence that can be started and stopped.
/// Takes at one sequence along with its configuration.
#[non_exhaustive]
pub struct SingleSequencer<'d, 's, T: Instance> {
sequencer: Sequencer<'d, 's, T>,
}
impl<'d, 's, T: Instance> SingleSequencer<'d, 's, T> {
/// Create a new sequencer
pub fn new(pwm: &'s mut SequencePwm<'d, T>, words: &'s [u16], config: SequenceConfig) -> Self {
Self {
sequencer: Sequencer::new(pwm, Sequence::new(words, config), None),
}
}
/// Start or restart playback.
#[inline(always)]
pub fn start(&self, times: SingleSequenceMode) -> Result<(), Error> {
let (start_seq, times) = match times {
SingleSequenceMode::Times(n) if n == 1 => (StartSequence::One, SequenceMode::Loop(1)),
SingleSequenceMode::Times(n) if n & 1 == 1 => (StartSequence::One, SequenceMode::Loop((n / 2) + 1)),
SingleSequenceMode::Times(n) => (StartSequence::Zero, SequenceMode::Loop(n / 2)),
SingleSequenceMode::Infinite => (StartSequence::Zero, SequenceMode::Infinite),
};
self.sequencer.start(start_seq, times)
}
/// Stop playback. Disables the peripheral. Does NOT clear the last duty
/// cycle from the pin. Returns any sequences previously provided to
/// `start` so that they may be further mutated.
#[inline(always)]
pub fn stop(&self) {
self.sequencer.stop();
}
}
/// A composition of sequences that can be started and stopped.
/// Takes at least one sequence along with its configuration.
/// Optionally takes a second sequence and its configuration.
/// In the case where no second sequence is provided then the first sequence
/// is used.
#[non_exhaustive]
pub struct Sequencer<'d, 's, T: Instance> {
_pwm: &'s mut SequencePwm<'d, T>,
sequence0: Sequence<'s>,
sequence1: Option<Sequence<'s>>,
}
impl<'d, 's, T: Instance> Sequencer<'d, 's, T> {
/// Create a new double sequence. In the absence of sequence 1, sequence 0
/// will be used twice in the one loop.
pub fn new(pwm: &'s mut SequencePwm<'d, T>, sequence0: Sequence<'s>, sequence1: Option<Sequence<'s>>) -> Self {
Sequencer {
_pwm: pwm,
sequence0,
sequence1,
}
}
/// Start or restart playback. The sequence mode applies to both sequences combined as one.
#[inline(always)]
pub fn start(&self, start_seq: StartSequence, times: SequenceMode) -> Result<(), Error> {
let sequence0 = &self.sequence0;
let alt_sequence = self.sequence1.as_ref().unwrap_or(&self.sequence0);
slice_in_ram_or(sequence0.words, Error::BufferNotInRAM)?;
slice_in_ram_or(alt_sequence.words, Error::BufferNotInRAM)?;
if sequence0.words.len() > MAX_SEQUENCE_LEN || alt_sequence.words.len() > MAX_SEQUENCE_LEN {
return Err(Error::SequenceTooLong);
}
if let SequenceMode::Loop(0) = times {
return Err(Error::SequenceTimesAtLeastOne);
}
let _ = self.stop();
let r = T::regs();
r.seq0.refresh.write(|w| unsafe { w.bits(sequence0.config.refresh) });
r.seq0.enddelay.write(|w| unsafe { w.bits(sequence0.config.end_delay) });
r.seq0.ptr.write(|w| unsafe { w.bits(sequence0.words.as_ptr() as u32) });
r.seq0.cnt.write(|w| unsafe { w.bits(sequence0.words.len() as u32) });
r.seq1.refresh.write(|w| unsafe { w.bits(alt_sequence.config.refresh) });
r.seq1
.enddelay
.write(|w| unsafe { w.bits(alt_sequence.config.end_delay) });
r.seq1
.ptr
.write(|w| unsafe { w.bits(alt_sequence.words.as_ptr() as u32) });
r.seq1.cnt.write(|w| unsafe { w.bits(alt_sequence.words.len() as u32) });
r.enable.write(|w| w.enable().enabled());
// defensive before seqstart
compiler_fence(Ordering::SeqCst);
let seqstart_index = if start_seq == StartSequence::One { 1 } else { 0 };
match times {
// just the one time, no loop count
SequenceMode::Loop(n) => {
r.loop_.write(|w| unsafe { w.cnt().bits(n) });
}
// to play infinitely, repeat the sequence one time, then have loops done self trigger seq0 again
SequenceMode::Infinite => {
r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
r.shorts.write(|w| w.loopsdone_seqstart0().enabled());
}
}
// tasks_seqstart() doesn't exist in all svds so write its bit instead
r.tasks_seqstart[seqstart_index].write(|w| unsafe { w.bits(0x01) });
Ok(())
}
/// Stop playback. Disables the peripheral. Does NOT clear the last duty
/// cycle from the pin. Returns any sequences previously provided to
/// `start` so that they may be further mutated.
#[inline(always)]
pub fn stop(&self) {
let r = T::regs();
r.shorts.reset();
compiler_fence(Ordering::SeqCst);
// tasks_stop() doesn't exist in all svds so write its bit instead
r.tasks_stop.write(|w| unsafe { w.bits(0x01) });
r.enable.write(|w| w.enable().disabled());
}
}
impl<'d, 's, T: Instance> Drop for Sequencer<'d, 's, T> {
fn drop(&mut self) {
let _ = self.stop();
}
}
/// How many times to run a single sequence
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum SingleSequenceMode {
/// Run a single sequence n Times total.
Times(u16),
/// Repeat until `stop` is called.
Infinite,
}
/// Which sequence to start a loop with
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum StartSequence {
/// Start with Sequence 0
Zero,
/// Start with Sequence 1
One,
}
/// How many loops to run two sequences
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum SequenceMode {
/// Run two sequences n loops i.e. (n * (seq0 + seq1.unwrap_or(seq0)))
Loop(u16),
/// Repeat until `stop` is called.
Infinite,
}
/// PWM Base clock is system clock (16MHz) divided by prescaler
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum Prescaler {
/// Divide by 1
Div1,
/// Divide by 2
Div2,
/// Divide by 4
Div4,
/// Divide by 8
Div8,
/// Divide by 16
Div16,
/// Divide by 32
Div32,
/// Divide by 64
Div64,
/// Divide by 128
Div128,
}
/// How the sequence values are distributed across the channels
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum SequenceLoad {
/// Provided sequence will be used across all channels
Common,
/// Provided sequence contains grouped values for each channel ex:
/// [ch0_0_and_ch1_0, ch2_0_and_ch3_0, ... ch0_n_and_ch1_n, ch2_n_and_ch3_n]
Grouped,
/// Provided sequence contains individual values for each channel ex:
/// [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
Individual,
/// Similar to Individual mode, but only three channels are used. The fourth
/// value is loaded into the pulse generator counter as its top value.
Waveform,
}
/// Selects up mode or up-and-down mode for the counter
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum CounterMode {
/// Up counter (edge-aligned PWM duty cycle)
Up,
/// Up and down counter (center-aligned PWM duty cycle)
UpAndDown,
}
impl<'d, T: Instance> SimplePwm<'d, T> {
/// Create a new 1-channel PWM
#[allow(unused_unsafe)]
pub fn new_1ch(pwm: impl Peripheral<P = T> + 'd, ch0: impl Peripheral<P = impl GpioPin> + 'd) -> Self {
unsafe {
into_ref!(ch0);
Self::new_inner(pwm, Some(ch0.map_into()), None, None, None)
}
}
/// Create a new 2-channel PWM
#[allow(unused_unsafe)]
pub fn new_2ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
ch1: impl Peripheral<P = impl GpioPin> + 'd,
) -> Self {
into_ref!(ch0, ch1);
Self::new_inner(pwm, Some(ch0.map_into()), Some(ch1.map_into()), None, None)
}
/// Create a new 3-channel PWM
#[allow(unused_unsafe)]
pub fn new_3ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
ch1: impl Peripheral<P = impl GpioPin> + 'd,
ch2: impl Peripheral<P = impl GpioPin> + 'd,
) -> Self {
unsafe {
into_ref!(ch0, ch1, ch2);
Self::new_inner(
pwm,
Some(ch0.map_into()),
Some(ch1.map_into()),
Some(ch2.map_into()),
None,
)
}
}
/// Create a new 4-channel PWM
#[allow(unused_unsafe)]
pub fn new_4ch(
pwm: impl Peripheral<P = T> + 'd,
ch0: impl Peripheral<P = impl GpioPin> + 'd,
ch1: impl Peripheral<P = impl GpioPin> + 'd,
ch2: impl Peripheral<P = impl GpioPin> + 'd,
ch3: impl Peripheral<P = impl GpioPin> + 'd,
) -> Self {
unsafe {
into_ref!(ch0, ch1, ch2, ch3);
Self::new_inner(
pwm,
Some(ch0.map_into()),
Some(ch1.map_into()),
Some(ch2.map_into()),
Some(ch3.map_into()),
)
}
}
fn new_inner(
_pwm: impl Peripheral<P = T> + 'd,
ch0: Option<PeripheralRef<'d, AnyPin>>,
ch1: Option<PeripheralRef<'d, AnyPin>>,
ch2: Option<PeripheralRef<'d, AnyPin>>,
ch3: Option<PeripheralRef<'d, AnyPin>>,
) -> Self {
into_ref!(_pwm);
let r = T::regs();
if let Some(pin) = &ch0 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
if let Some(pin) = &ch1 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
if let Some(pin) = &ch2 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
if let Some(pin) = &ch3 {
pin.set_low();
pin.conf().write(|w| w.dir().output());
}
// if NoPin provided writes disconnected (top bit 1) 0x80000000 else
// writes pin number ex 13 (0x0D) which is connected (top bit 0)
r.psel.out[0].write(|w| unsafe { w.bits(ch0.psel_bits()) });
r.psel.out[1].write(|w| unsafe { w.bits(ch1.psel_bits()) });
r.psel.out[2].write(|w| unsafe { w.bits(ch2.psel_bits()) });
r.psel.out[3].write(|w| unsafe { w.bits(ch3.psel_bits()) });
let pwm = Self {
_peri: _pwm,
ch0,
ch1,
ch2,
ch3,
duty: [0; 4],
};
// Disable all interrupts
r.intenclr.write(|w| unsafe { w.bits(0xFFFF_FFFF) });
r.shorts.reset();
// Enable
r.enable.write(|w| w.enable().enabled());
r.seq0.ptr.write(|w| unsafe { w.bits((&pwm.duty).as_ptr() as u32) });
r.seq0.cnt.write(|w| unsafe { w.bits(4) });
r.seq0.refresh.write(|w| unsafe { w.bits(0) });
r.seq0.enddelay.write(|w| unsafe { w.bits(0) });
r.decoder.write(|w| {
w.load().individual();
w.mode().refresh_count()
});
r.mode.write(|w| w.updown().up());
r.prescaler.write(|w| w.prescaler().div_16());
r.countertop.write(|w| unsafe { w.countertop().bits(1000) });
r.loop_.write(|w| w.cnt().disabled());
pwm
}
/// Enables the PWM generator.
#[inline(always)]
pub fn enable(&self) {
let r = T::regs();
r.enable.write(|w| w.enable().enabled());
}
/// Disables the PWM generator. Does NOT clear the last duty cycle from the pin.
#[inline(always)]
pub fn disable(&self) {
let r = T::regs();
r.enable.write(|w| w.enable().disabled());
}
/// Sets duty cycle (15 bit) for a PWM channel.
pub fn set_duty(&mut self, channel: usize, duty: u16) {
let r = T::regs();
self.duty[channel] = duty & 0x7FFF;
// reload ptr in case self was moved
r.seq0.ptr.write(|w| unsafe { w.bits((&self.duty).as_ptr() as u32) });
// defensive before seqstart
compiler_fence(Ordering::SeqCst);
r.events_seqend[0].reset();
// tasks_seqstart() doesn't exist in all svds so write its bit instead
r.tasks_seqstart[0].write(|w| unsafe { w.bits(1) });
// defensive wait until waveform is loaded after seqstart so set_duty
// can't be called again while dma is still reading
while r.events_seqend[0].read().bits() == 0 {}
}
/// Sets the PWM clock prescaler.
#[inline(always)]
pub fn set_prescaler(&self, div: Prescaler) {
T::regs().prescaler.write(|w| w.prescaler().bits(div as u8));
}
/// Gets the PWM clock prescaler.
#[inline(always)]
pub fn prescaler(&self) -> Prescaler {
match T::regs().prescaler.read().prescaler().bits() {
0 => Prescaler::Div1,
1 => Prescaler::Div2,
2 => Prescaler::Div4,
3 => Prescaler::Div8,
4 => Prescaler::Div16,
5 => Prescaler::Div32,
6 => Prescaler::Div64,
7 => Prescaler::Div128,
_ => unreachable!(),
}
}
/// Sets the maximum duty cycle value.
#[inline(always)]
pub fn set_max_duty(&self, duty: u16) {
T::regs()
.countertop
.write(|w| unsafe { w.countertop().bits(duty.min(32767u16)) });
}
/// Returns the maximum duty cycle value.
#[inline(always)]
pub fn max_duty(&self) -> u16 {
T::regs().countertop.read().countertop().bits()
}
/// Sets the PWM output frequency.
#[inline(always)]
pub fn set_period(&self, freq: u32) {
let clk = 16_000_000u32 >> (self.prescaler() as u8);
let duty = clk / freq;
self.set_max_duty(duty.min(32767) as u16);
}
/// Returns the PWM output frequency.
#[inline(always)]
pub fn period(&self) -> u32 {
let clk = 16_000_000u32 >> (self.prescaler() as u8);
let max_duty = self.max_duty() as u32;
clk / max_duty
}
}
impl<'a, T: Instance> Drop for SimplePwm<'a, T> {
fn drop(&mut self) {
let r = T::regs();
self.disable();
if let Some(pin) = &self.ch0 {
pin.set_low();
pin.conf().reset();
r.psel.out[0].reset();
}
if let Some(pin) = &self.ch1 {
pin.set_low();
pin.conf().reset();
r.psel.out[1].reset();
}
if let Some(pin) = &self.ch2 {
pin.set_low();
pin.conf().reset();
r.psel.out[2].reset();
}
if let Some(pin) = &self.ch3 {
pin.set_low();
pin.conf().reset();
r.psel.out[3].reset();
}
}
}
pub(crate) mod sealed {
use super::*;
pub trait Instance {
fn regs() -> &'static pac::pwm0::RegisterBlock;
}
}
/// PWM peripheral instance.
pub trait Instance: Peripheral<P = Self> + sealed::Instance + 'static {
/// Interrupt for this peripheral.
type Interrupt: interrupt::typelevel::Interrupt;
}
macro_rules! impl_pwm {
($type:ident, $pac_type:ident, $irq:ident) => {
impl crate::pwm::sealed::Instance for peripherals::$type {
fn regs() -> &'static pac::pwm0::RegisterBlock {
unsafe { &*pac::$pac_type::ptr() }
}
}
impl crate::pwm::Instance for peripherals::$type {
type Interrupt = crate::interrupt::typelevel::$irq;
}
};
}
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