Merge pull request #226 from huntc/mpsc

Multi Producer Single Consumer channel

examples/nrf/src/bin/mpsc.rs

@@ -0,0 +1,65 @@
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+
+use defmt::panic;
+use embassy::executor::Spawner;
+use embassy::time::{Duration, Timer};
+use embassy::util::mpsc::TryRecvError;
+use embassy::util::{mpsc, Forever};
+use embassy_nrf::gpio::{Level, Output, OutputDrive};
+use embassy_nrf::Peripherals;
+use embedded_hal::digital::v2::OutputPin;
+use mpsc::{Channel, Sender, WithNoThreads};
+
+enum LedState {
+    On,
+    Off,
+}
+
+static CHANNEL: Forever<Channel<WithNoThreads, LedState, 1>> = Forever::new();
+
+#[embassy::task(pool_size = 1)]
+async fn my_task(sender: Sender<'static, WithNoThreads, LedState, 1>) {
+    loop {
+        let _ = sender.send(LedState::On).await;
+        Timer::after(Duration::from_secs(1)).await;
+        let _ = sender.send(LedState::Off).await;
+        Timer::after(Duration::from_secs(1)).await;
+    }
+}
+
+#[embassy::main]
+async fn main(spawner: Spawner, p: Peripherals) {
+    
+    let mut led = Output::new(p.P0_13, Level::Low, OutputDrive::Standard);
+
+    let channel = CHANNEL.put(Channel::new());
+    let (sender, mut receiver) = mpsc::split(channel);
+
+    spawner.spawn(my_task(sender)).unwrap();
+
+    // We could just loop on `receiver.recv()` for simplicity. The code below
+    // is optimized to drain the queue as fast as possible in the spirit of
+    // handling events as fast as possible. This optimization is benign when in
+    // thread mode, but can be useful when interrupts are sending messages
+    // with the channel having been created via with_critical_sections.
+    loop {
+        let maybe_message = match receiver.try_recv() {
+            m @ Ok(..) => m.ok(),
+            Err(TryRecvError::Empty) => receiver.recv().await,
+            Err(TryRecvError::Closed) => break,
+        };
+        match maybe_message {
+            Some(LedState::On) => led.set_high().unwrap(),
+            Some(LedState::Off) => led.set_low().unwrap(),
+            _ => (),
+        }
+    }
+}