embassy/examples/nrf52840/src/bin/pwm_sequence.rs

#![no_std]
#![no_main]
#![feature(type_alias_impl_trait)]

use defmt::*;
use embassy_executor::Spawner;
use embassy_nrf::pwm::{Config, Prescaler, SequenceConfig, SequencePwm, SingleSequenceMode, SingleSequencer};
use embassy_time::{Duration, Timer};
use {defmt_rtt as _, panic_probe as _};

#[embassy_executor::main]
async fn main(_spawner: Spawner) {
    let p = embassy_nrf::init(Default::default());
    let seq_words: [u16; 5] = [1000, 250, 100, 50, 0];

    let mut config = Config::default();
    config.prescaler = Prescaler::Div128;
    // 1 period is 1000 * (128/16mhz = 0.000008s = 0.008ms) = 8us
    // but say we want to hold the value for 5000ms
    // so we want to repeat our value as many times as necessary until 5000ms passes
    // want 5000/8 = 625 periods total to occur, so 624 (we get the one period for free remember)
    let mut seq_config = SequenceConfig::default();
    seq_config.refresh = 624;
    // thus our sequence takes 5 * 5000ms or 25 seconds

    let mut pwm = unwrap!(SequencePwm::new_1ch(p.PWM0, p.P0_13, config,));

    let sequencer = SingleSequencer::new(&mut pwm, &seq_words, seq_config);
    unwrap!(sequencer.start(SingleSequenceMode::Times(1)));

    // we can abort a sequence if we need to before its complete with pwm.stop()
    // or stop is also implicitly called when the pwm peripheral is dropped
    // when it goes out of scope
    Timer::after(Duration::from_millis(20000)).await;
    info!("pwm stopped early!");
}