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#![no_std]
#![no_main]
/// This example demonstrates how to access a given pin from more than one embassy task
/// The on-board LED is toggled by two tasks with slightly different periods, leading to the
/// apparent duty cycle of the LED increasing, then decreasing, linearly. The phenomenon is similar
/// to interference and the 'beats' you can hear if you play two frequencies close to one another
/// [Link explaining it](https://www.physicsclassroom.com/class/sound/Lesson-3/Interference-and-Beats)
use defmt::*;
use embassy_executor::Spawner;
use embassy_rp::gpio;
use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
use embassy_sync::mutex::Mutex;
use embassy_time::{Duration, Ticker};
use gpio::{Level, Output};
use {defmt_rtt as _, panic_probe as _};
type LedType = Mutex<ThreadModeRawMutex, Option<Output<'static>>>;
static LED: LedType = Mutex::new(None);
#[embassy_executor::main]
async fn main(spawner: Spawner) {
let p = embassy_rp::init(Default::default());
// set the content of the global LED reference to the real LED pin
let led = Output::new(p.PIN_25, Level::High);
// inner scope is so that once the mutex is written to, the MutexGuard is dropped, thus the
// Mutex is released
{
*(LED.lock().await) = Some(led);
}
let dt = 100 * 1_000_000;
let k = 1.003;
unwrap!(spawner.spawn(toggle_led(&LED, Duration::from_nanos(dt))));
unwrap!(spawner.spawn(toggle_led(&LED, Duration::from_nanos((dt as f64 * k) as u64))));
}
#[embassy_executor::task(pool_size = 2)]
async fn toggle_led(led: &'static LedType, delay: Duration) {
let mut ticker = Ticker::every(delay);
loop {
{
let mut led_unlocked = led.lock().await;
if let Some(pin_ref) = led_unlocked.as_mut() {
pin_ref.toggle();
}
}
ticker.next().await;
}
}
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