embassy/examples/nrf/src/bin/pwm_sequence.rs
2022-08-18 01:22:30 +02:00

37 lines
1.4 KiB
Rust

#![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!");
}