Add timeout and delay example

examples/async-delay.rs

@@ -0,0 +1,67 @@
+#![no_main]
+#![no_std]
+#![feature(type_alias_impl_trait)]
+
+use panic_semihosting as _;
+
+#[rtic::app(device = lm3s6965, dispatchers = [SSI0, UART0], peripherals = true)]
+mod app {
+    use cortex_m_semihosting::{debug, hprintln};
+    use systick_monotonic::*;
+
+    #[shared]
+    struct Shared {}
+
+    #[local]
+    struct Local {}
+
+    #[monotonic(binds = SysTick, default = true)]
+    type MyMono = Systick<100>;
+
+    #[init]
+    fn init(cx: init::Context) -> (Shared, Local, init::Monotonics) {
+        hprintln!("init").unwrap();
+
+        foo::spawn().ok();
+        bar::spawn().ok();
+        baz::spawn().ok();
+
+        (
+            Shared {},
+            Local {},
+            init::Monotonics(Systick::new(cx.core.SYST, 12_000_000)),
+        )
+    }
+
+    #[idle]
+    fn idle(_: idle::Context) -> ! {
+        // debug::exit(debug::EXIT_SUCCESS);
+        loop {
+            // hprintln!("idle");
+            cortex_m::asm::wfi(); // put the MCU in sleep mode until interrupt occurs
+        }
+    }
+
+    #[task]
+    async fn foo(_cx: foo::Context) {
+        hprintln!("hello from foo").ok();
+        monotonics::delay(100.millis()).await;
+        hprintln!("bye from foo").ok();
+    }
+
+    #[task]
+    async fn bar(_cx: bar::Context) {
+        hprintln!("hello from bar").ok();
+        monotonics::delay(200.millis()).await;
+        hprintln!("bye from bar").ok();
+    }
+
+    #[task]
+    async fn baz(_cx: baz::Context) {
+        hprintln!("hello from baz").ok();
+        monotonics::delay(300.millis()).await;
+        hprintln!("bye from baz").ok();
+
+        debug::exit(debug::EXIT_SUCCESS);
+    }
+}

examples/async-timeout.rs

@@ -0,0 +1,87 @@
+#![no_main]
+#![no_std]
+#![feature(type_alias_impl_trait)]
+
+use panic_semihosting as _;
+
+// NOTES:
+//
+// - Async tasks cannot have `#[lock_free]` resources, as they can interleve and each async
+//   task can have a mutable reference stored.
+// - Spawning an async task equates to it being polled once.
+
+#[rtic::app(device = lm3s6965, dispatchers = [SSI0, UART0], peripherals = true)]
+mod app {
+    use core::{
+        future::Future,
+        pin::Pin,
+        task::{Context, Poll},
+    };
+    use cortex_m_semihosting::{debug, hprintln};
+    use systick_monotonic::*;
+
+    #[shared]
+    struct Shared {}
+
+    #[local]
+    struct Local {}
+
+    #[monotonic(binds = SysTick, default = true)]
+    type MyMono = Systick<100>;
+
+    #[init]
+    fn init(cx: init::Context) -> (Shared, Local, init::Monotonics) {
+        hprintln!("init").unwrap();
+
+        foo::spawn().ok();
+        bar::spawn().ok();
+
+        (
+            Shared {},
+            Local {},
+            init::Monotonics(Systick::new(cx.core.SYST, 12_000_000)),
+        )
+    }
+
+    #[idle]
+    fn idle(_: idle::Context) -> ! {
+        loop {
+            cortex_m::asm::wfi(); // put the MCU in sleep mode until interrupt occurs
+        }
+    }
+
+    #[task]
+    async fn foo(_cx: foo::Context) {
+        hprintln!("hello from foo").ok();
+
+        // This will not timeout
+        match monotonics::timeout_after(monotonics::delay(100.millis()), 200.millis()).await {
+            Ok(_) => hprintln!("foo no timeout").ok(),
+            Err(_) => hprintln!("foo timeout").ok(),
+        };
+    }
+
+    #[task]
+    async fn bar(_cx: bar::Context) {
+        hprintln!("hello from bar").ok();
+
+        // This will timeout
+        match monotonics::timeout_after(NeverEndingFuture {}, 300.millis()).await {
+            Ok(_) => hprintln!("bar no timeout").ok(),
+            Err(_) => hprintln!("bar timeout").ok(),
+        };
+
+        debug::exit(debug::EXIT_SUCCESS);
+    }
+
+    pub struct NeverEndingFuture {}
+
+    impl Future for NeverEndingFuture {
+        type Output = ();
+
+        fn poll(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Self::Output> {
+            // Never finish
+            Poll::Pending
+        }
+    }
+}