embassy/examples/stm32f3/src/bin/button_events.rs

//! This example showcases channels and timing utilities of embassy.
//!
//! This example works best on STM32F3DISCOVERY board. It flashes a single LED, then if the USER
//! button is pressed the next LED is flashed (in clockwise fashion). If the USER button is double
//! clicked, then the direction changes. If the USER button is pressed for 1 second, then all the
//! LEDS flash 3 times.
//!

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

#[path = "../example_common.rs"]
mod example_common;
use embassy::blocking_mutex::kind::Noop;
use embassy::channel::mpsc::{self, Channel, Receiver, Sender};
use embassy::executor::Spawner;
use embassy::time::{with_timeout, Duration, Timer};
use embassy::util::Forever;
use embassy_stm32::exti::ExtiInput;
use embassy_stm32::gpio::{AnyPin, Input, Level, Output, Pin, Pull, Speed};
use embassy_stm32::peripherals::PA0;
use embassy_stm32::Peripherals;
use example_common::*;

struct Leds<'a> {
    leds: [Output<'a, AnyPin>; 8],
    direction: i8,
    current_led: usize,
}

impl<'a> Leds<'a> {
    fn new(pins: [Output<'a, AnyPin>; 8]) -> Self {
        Self {
            leds: pins,
            direction: 1,
            current_led: 0,
        }
    }

    fn change_direction(&mut self) {
        self.direction *= -1;
    }

    fn move_next(&mut self) {
        if self.direction > 0 {
            self.current_led = (self.current_led + 1) & 7;
        } else {
            self.current_led = (8 + self.current_led - 1) & 7;
        }
    }

    async fn blink(&mut self) {
        self.leds[self.current_led].set_high();
        Timer::after(Duration::from_millis(500)).await;
        self.leds[self.current_led].set_low();
        Timer::after(Duration::from_millis(200)).await;
    }

    async fn flash(&mut self) {
        for _ in 0..3 {
            for led in &mut self.leds {
                led.set_high();
            }
            Timer::after(Duration::from_millis(500)).await;
            for led in &mut self.leds {
                led.set_low();
            }
            Timer::after(Duration::from_millis(200)).await;
        }
    }
}

enum ButtonEvent {
    SingleClick,
    DoubleClick,
    Hold,
}

static BUTTON_EVENTS_QUEUE: Forever<Channel<Noop, ButtonEvent, 4>> = Forever::new();

#[embassy::main]
async fn main(spawner: Spawner, p: Peripherals) {
    let button = Input::new(p.PA0, Pull::Down);
    let button = ExtiInput::new(button, p.EXTI0);
    info!("Press the USER button...");
    let leds = [
        Output::new(p.PE9.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE10.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE11.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE12.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE13.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE14.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE15.degrade(), Level::Low, Speed::Low),
        Output::new(p.PE8.degrade(), Level::Low, Speed::Low),
    ];
    let leds = Leds::new(leds);

    let buttons_queue = BUTTON_EVENTS_QUEUE.put(Channel::new());
    let (sender, receiver) = mpsc::split(buttons_queue);
    spawner.spawn(button_waiter(button, sender)).unwrap();
    spawner.spawn(led_blinker(leds, receiver)).unwrap();
}

#[embassy::task]
async fn led_blinker(mut leds: Leds<'static>, queue: Receiver<'static, Noop, ButtonEvent, 4>) {
    loop {
        leds.blink().await;
        match queue.try_recv() {
            Ok(ButtonEvent::SingleClick) => leds.move_next(),
            Ok(ButtonEvent::DoubleClick) => {
                leds.change_direction();
                leds.move_next()
            }
            Ok(ButtonEvent::Hold) => leds.flash().await,
            _ => {}
        }
    }
}

#[embassy::task]
async fn button_waiter(
    mut button: ExtiInput<'static, PA0>,
    queue: Sender<'static, Noop, ButtonEvent, 4>,
) {
    const DOUBLE_CLICK_DELAY: u64 = 250;
    const HOLD_DELAY: u64 = 1000;

    button.wait_for_rising_edge().await;
    loop {
        if with_timeout(
            Duration::from_millis(HOLD_DELAY),
            button.wait_for_falling_edge(),
        )
        .await
        .is_err()
        {
            info!("Hold");
            if queue.send(ButtonEvent::Hold).await.is_err() {
                break;
            }
            button.wait_for_falling_edge().await;
        } else if with_timeout(
            Duration::from_millis(DOUBLE_CLICK_DELAY),
            button.wait_for_rising_edge(),
        )
        .await
        .is_err()
        {
            if queue.send(ButtonEvent::SingleClick).await.is_err() {
                break;
            }
            info!("Single click");
        } else {
            info!("Double click");
            if queue.send(ButtonEvent::DoubleClick).await.is_err() {
                break;
            }
            button.wait_for_falling_edge().await;
        }
        button.wait_for_rising_edge().await;
    }
}