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

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

#[path = "../example_common.rs"]
mod example_common;
use defmt::*;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_nrf::gpio::NoPin;
use embassy_nrf::pwm::{
    Config, Prescaler, Sequence, SequenceConfig, SequenceMode, SequencePwm, EMPTY_SEQ,
};
use embassy_nrf::Peripherals;

#[embassy::main]
async fn main(_spawner: Spawner, p: Peripherals) {
    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 seq_1 = Sequence::new([1000, 250, 100, 50, 0], seq_config.clone());
    let seq_2 = Sequence::new([0, 50, 100, 250, 1000], seq_config);

    let mut pwm = unwrap!(SequencePwm::new(
        p.PWM0, p.P0_13, NoPin, NoPin, NoPin, config,
    ));
    unwrap!(pwm.start(seq_1, EMPTY_SEQ, SequenceMode::Times(1)));

    info!("pwm started!");

    Timer::after(Duration::from_millis(20000)).await;
    info!("pwm starting with another sequence!");

    unwrap!(pwm.start(seq_2, EMPTY_SEQ, SequenceMode::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!");
}