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add ability to configure loop count from 1 to infinite

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This commit is contained in:
Jacob Rosenthal 2021-10-30 16:16:10 -07:00
parent ee8f76537b
commit 763e250dfe
3 changed files with 65 additions and 29 deletions
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67
embassy-nrf/src/pwm.rs
View File

@ -24,10 +24,13 @@ pub enum Prescaler {
Div128,
}
/// How a sequence is read from RAM and is spread to the compare register
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum SequenceLoad {
/// sequence in buffer will be used across all channels
Common,
Grouped,
/// buffer holds [ch0_0, ch1_0, ch2_0, ch3_0... ch0_n, ch1_n, ch2_n, ch3_n]
Individual,
Waveform,
}
@ -43,26 +46,32 @@ pub struct Pwm<'d, T: Instance> {
phantom: PhantomData<&'d mut T>,
}
#[derive(Debug, Eq, PartialEq, Clone, Copy)]
pub enum LoopMode {
// Repeat n additional times after the first
Additional(u16),
/// Repeat until `stop` is called
Infinite,
}
// Configure an infinite looping sequence for `simple_playback`
pub struct LoopingConfig<'a> {
/// Selects up mode or up-and-down mode for the counter
pub counter_mode: CounterMode,
// top value to be compared against buffer values
// Top value to be compared against buffer values
pub top: u16,
/// Configuration for PWM_CLK
pub prescaler: Prescaler,
/// In ram buffer to be played back
pub sequence: &'a [u16],
/// Common Mode means seq in buffer will be used across all channels
/// Individual Mode buffer holds [ch0_0, ch1_0, ch2_0, ch3_0, ch0_1, ch1_1,
/// ch2_1, ch3_1 ... ch0_n, ch1_n, ch2_n, ch3_n]
/// How a sequence is read from RAM and is spread to the compare register
pub sequence_load: SequenceLoad,
/// will instruct a new RAM stored pulse width value on every (N+1)th PWM
/// period. Setting the register to zero will result in a new duty cycle
/// update every PWM period as long as the minimum PWM period is observed.
pub repeats: u32,
/// enddelay PWM period delays between last period on sequence 0 before repeating
/// Number of additional PWM periods between samples loaded into compare register
pub refresh: u32,
/// Number of additional PWM periods after the sequence ends
pub enddelay: u32,
/// How many times to repeat the sequence
pub additional_loops: LoopMode,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
@ -146,6 +155,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
}
}
/// Returns a configured pwm that has had start called on it
pub fn simple_playback(
_pwm: impl Unborrow<Target = T> + 'd,
ch0: impl Unborrow<Target = impl GpioOptionalPin> + 'd,
@ -209,7 +219,7 @@ impl<'d, T: Instance> Pwm<'d, T> {
r.seq0
.cnt
.write(|w| unsafe { w.bits(config.sequence.len() as u32) });
r.seq0.refresh.write(|w| unsafe { w.bits(config.repeats) });
r.seq0.refresh.write(|w| unsafe { w.bits(config.refresh) });
r.seq0
.enddelay
.write(|w| unsafe { w.bits(config.enddelay) });
@ -220,17 +230,42 @@ impl<'d, T: Instance> Pwm<'d, T> {
r.seq1
.cnt
.write(|w| unsafe { w.bits(config.sequence.len() as u32) });
r.seq1.refresh.write(|w| unsafe { w.bits(config.repeats) });
r.seq1.refresh.write(|w| unsafe { w.bits(config.refresh) });
r.seq1
.enddelay
.write(|w| unsafe { w.bits(config.enddelay) });
r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
match config.additional_loops {
LoopMode::Additional(0) => {
r.loop_.write(|w| w.cnt().disabled());
r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
}
LoopMode::Additional(n) => {
let times = (n / 2) + 1;
r.shorts.write(|w| w.loopsdone_seqstart1().set_bit());
r.loop_.write(|w| unsafe { w.cnt().bits(times) });
r.shorts.write(|w| {
w.loopsdone_seqstart1().enabled();
w.loopsdone_seqstart0().disabled();
w.loopsdone_stop().enabled()
});
// tasks_seqstart doesnt exist in all svds so write its bit instead
if n & 1 == 1 {
r.tasks_seqstart[0].write(|w| unsafe { w.bits(0x01) });
} else {
r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
}
}
LoopMode::Infinite => {
r.loop_.write(|w| unsafe { w.cnt().bits(0x1) });
r.shorts.write(|w| {
w.loopsdone_seqstart1().enabled();
w.loopsdone_seqstart0().disabled()
});
r.tasks_seqstart[1].write(|w| unsafe { w.bits(0x01) });
}
}
Ok(Self {
phantom: PhantomData,
@ -326,10 +361,8 @@ impl<'d, T: Instance> Pwm<'d, T> {
impl<'a, T: Instance> Drop for Pwm<'a, T> {
fn drop(&mut self) {
let r = T::regs();
self.stop();
r.enable.write(|w| w.enable().disabled());
self.disable();
info!("pwm drop: done");

13
examples/nrf/src/bin/pwm_sequence.rs
View File

@ -7,7 +7,7 @@ mod example_common;
use defmt::*;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
use embassy_nrf::pwm::{CounterMode, LoopMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
use embassy_nrf::Peripherals;
#[embassy::main]
@ -15,26 +15,23 @@ async fn main(_spawner: Spawner, p: Peripherals) {
let seq_values: [u16; 16] = [
0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000, 0, 0, 0, 0, 0x8000,
];
let config = LoopingConfig {
counter_mode: CounterMode::Up,
top: 15625,
prescaler: Prescaler::Div128,
sequence: &seq_values,
sequence_load: SequenceLoad::Individual,
repeats: 0,
refresh: 0,
enddelay: 0,
additional_loops: LoopMode::Additional(5),
};
let pwm = unwrap!(Pwm::simple_playback(
let _pwm = unwrap!(Pwm::simple_playback(
p.PWM0, p.P0_13, p.P0_15, p.P0_16, p.P0_14, config
));
info!("pwm started!");
Timer::after(Duration::from_millis(10000)).await;
pwm.stop();
info!("pwm stopped!");
loop {
Timer::after(Duration::from_millis(1000)).await;
}

12
examples/nrf/src/bin/pwm_simple_sin.rs
View File

@ -9,7 +9,7 @@ use defmt::*;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_nrf::gpio::NoPin;
use embassy_nrf::pwm::{CounterMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
use embassy_nrf::pwm::{CounterMode, LoopMode, LoopingConfig, Prescaler, Pwm, SequenceLoad};
use embassy_nrf::Peripherals;
use micromath::F32Ext;
@ -26,15 +26,21 @@ async fn main(_spawner: Spawner, p: Peripherals) {
prescaler: Prescaler::Div16,
sequence: &seq_values,
sequence_load: SequenceLoad::Common,
repeats: 0,
refresh: 0,
enddelay: 0,
additional_loops: LoopMode::Infinite,
};
let _pwm = unwrap!(Pwm::simple_playback(
let pwm = unwrap!(Pwm::simple_playback(
p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config
));
info!("pwm started!");
Timer::after(Duration::from_millis(20000)).await;
pwm.stop();
info!("pwm stopped!");
loop {
Timer::after(Duration::from_millis(1000)).await;
}