cleanup docs and add channel synchronization example

1 files changed, 47 insertions, 0 deletions

diff --git a/examples/rp/src/bin/blinky_two_channels.rs b/examples/rp/src/bin/blinky_two_channels.rs
new file mode 100644
index 000000000..6179dc260
--- /dev/null
+++ b/examples/rp/src/bin/blinky_two_channels.rs
@@ -0,0 +1,47 @@
+#![no_std]
+#![no_main]
+/// This example demonstrates how to access a given pin from more than one embassy task
+/// The on-board LED is toggled by two tasks with slightly different periods, leading to the
+/// apparent duty cycle of the LED increasing, then decreasing, linearly. The phenomenon is similar
+/// to interference and the 'beats' you can hear if you play two frequencies close to one another
+/// [Link explaining it](https://www.physicsclassroom.com/class/sound/Lesson-3/Interference-and-Beats)
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::gpio;
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::{Channel, Sender};
+use embassy_time::{Duration, Ticker};
+use gpio::{AnyPin, Level, Output};
+use {defmt_rtt as _, panic_probe as _};
+
+enum LedState {
+     Toggle,
+}
+static CHANNEL: Channel<ThreadModeRawMutex, LedState, 64> = Channel::new();
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let p = embassy_rp::init(Default::default());
+    let mut led = Output::new(AnyPin::from(p.PIN_25), Level::High);
+
+    let dt = 100 * 1_000_000;
+    let k = 1.003;
+
+    unwrap!(spawner.spawn(toggle_led(CHANNEL.sender(), Duration::from_nanos(dt))));
+    unwrap!(spawner.spawn(toggle_led(CHANNEL.sender(), Duration::from_nanos((dt as f64 * k) as u64))));
+
+    loop {
+        match CHANNEL.receive().await {
+            LedState::Toggle => led.toggle(),
+        }
+    }
+}
+
+#[embassy_executor::task(pool_size = 2)]
+async fn toggle_led(control: Sender<'static, ThreadModeRawMutex, LedState, 64>, delay: Duration) {
+    let mut ticker = Ticker::every(delay);
+    loop {
+        control.send(LedState::Toggle).await;
+        ticker.next().await;
+    }
+}