button controlled example

examples/stm32f0/src/bin/button_controlled_blink.rs

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+//! This example showcases how to create task
+
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use core::sync::atomic::{AtomicU32, Ordering};
+
+use defmt::info;
+use embassy_executor::Spawner;
+use embassy_stm32::exti::ExtiInput;
+use embassy_stm32::gpio::{AnyPin, Input, Level, Output, Pin, Pull, Speed};
+use embassy_time::{Duration, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+static BLINK_MS: AtomicU32 = AtomicU32::new(0);
+
+#[embassy_executor::task]
+async fn led_task(led: AnyPin) {
+    // Configure the LED pin as a push pull ouput and obtain handler.
+    // On the Nucleo F091RC theres an on-board LED connected to pin PA5.
+    let mut led = Output::new(led, Level::Low, Speed::Low);
+
+    loop {
+        let del = BLINK_MS.load(Ordering::Relaxed);
+        info!("Value of del is {}", del);
+        Timer::after(Duration::from_millis(del.into())).await;
+        info!("LED toggling");
+        led.toggle();
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    // Initialize and create handle for devicer peripherals
+    let p = embassy_stm32::init(Default::default());
+
+    // Configure the button pin and obtain handler.
+    // On the Nucleo F091RC there is a button connected to pin PC13.
+    let button = Input::new(p.PC13, Pull::None);
+    let mut button = ExtiInput::new(button, p.EXTI13);
+
+    // Create and initialize a delay variable to manage delay loop
+    let mut del_var = 2000;
+
+    // Blink duration value to global context
+    BLINK_MS.store(del_var, Ordering::Relaxed);
+
+    // Spawn LED blinking task
+    spawner.spawn(led_task(p.PA5.degrade())).unwrap();
+
+    loop {
+        // Check if button got pressed
+        button.wait_for_rising_edge().await;
+        info!("rising_edge");
+        del_var = del_var - 200;
+        // If updated delay value drops below 200 then reset it back to starting value
+        if del_var < 200 {
+            del_var = 2000;
+        }
+        // Updated delay value to global context
+        BLINK_MS.store(del_var, Ordering::Relaxed);
+    }
+}