Add support for multi alarm to RTC.

embassy/src/executor.rs

@@ -27,6 +27,7 @@ pub struct Executor<M, A: Alarm> {
 
 impl<M: Model, A: Alarm> Executor<M, A> {
     pub fn new(alarm: A) -> Self {
+        alarm.set_callback(M::signal);
         Self {
             inner: se::Executor::new(M::signal),
             alarm,
@@ -53,7 +54,7 @@ impl<M: Model, A: Alarm> Executor<M, A> {
             match self.timer.next_expiration() {
                 // If this is in the past, set_alarm will immediately trigger the alarm,
                 // which will make the wfe immediately return so we do another loop iteration.
-                Some(at) => self.alarm.set(at, M::signal),
+                Some(at) => self.alarm.set(at),
                 None => self.alarm.clear(),
             }
         })

embassy/src/time.rs

@@ -273,13 +273,17 @@ impl Future for Timer {
 
 /// Trait to register a callback at a given timestamp.
 pub trait Alarm {
+    /// Sets the callback function to be called when the alarm triggers.
+    /// The callback may be called from any context (interrupt or thread mode).
+    fn set_callback(&self, callback: fn());
+
     /// Sets an alarm at the given timestamp. When the clock reaches that
     /// timestamp, the provided callback funcion will be called.
     ///
     /// When callback is called, it is guaranteed that now() will return a value greater or equal than timestamp.
     ///
     /// Only one alarm can be active at a time. This overwrites any previously-set alarm if any.
-    fn set(&self, timestamp: u64, callback: fn());
+    fn set(&self, timestamp: u64);
 
     /// Clears the previously-set alarm.
     /// If no alarm was set, this is a noop.