stm32: add rust stable support

examples/stm32l0/src/bin/raw_spawn.rs

@@ -0,0 +1,54 @@
+#![no_std]
+#![no_main]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use core::mem;
+use cortex_m_rt::entry;
+
+use embassy::executor::raw::TaskStorage;
+use embassy::executor::Executor;
+use embassy::time::{Duration, Timer};
+use embassy::util::Forever;
+
+async fn run1() {
+    loop {
+        info!("BIG INFREQUENT TICK");
+        Timer::after(Duration::from_ticks(64000)).await;
+    }
+}
+
+async fn run2() {
+    loop {
+        info!("tick");
+        Timer::after(Duration::from_ticks(13000)).await;
+    }
+}
+
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let _p = embassy_stm32::init(Default::default());
+    let executor = EXECUTOR.put(Executor::new());
+
+    let run1_task = TaskStorage::new();
+    let run2_task = TaskStorage::new();
+
+    // Safety: these variables do live forever if main never returns.
+    let run1_task = unsafe { make_static(&run1_task) };
+    let run2_task = unsafe { make_static(&run2_task) };
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(run1_task.spawn(|| run1())));
+        unwrap!(spawner.spawn(run2_task.spawn(|| run2())));
+    });
+}
+
+unsafe fn make_static<T>(t: &T) -> &'static T {
+    mem::transmute(t)
+}