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