1//! Asynchronous digital I/O.
2//!
3//! # Example
4//!
5//! ```rust
6//! # use embedded_hal_async::digital::Wait;
7//! /// Asynchronously wait until the `ready_pin` becomes high.
8//! async fn wait_until_ready<P>(ready_pin: &mut P)
9//! where
10//! P: Wait,
11//! {
12//! ready_pin
13//! .wait_for_high()
14//! .await
15//! .expect("failed to await input pin")
16//! }
17//! ```
18
19/// Asynchronously wait for GPIO pin state.
20pub trait Wait: embedded_hal::digital::ErrorType {
21 /// Wait until the pin is high. If it is already high, return immediately.
22 ///
23 /// # Note for implementers
24 /// The pin may have switched back to low before the task was run after
25 /// being woken. The future should still resolve in that case.
26 async fn wait_for_high(&mut self) -> Result<(), Self::Error>;
27
28 /// Wait until the pin is low. If it is already low, return immediately.
29 ///
30 /// # Note for implementers
31 /// The pin may have switched back to high before the task was run after
32 /// being woken. The future should still resolve in that case.
33 async fn wait_for_low(&mut self) -> Result<(), Self::Error>;
34
35 /// Wait for the pin to undergo a transition from low to high.
36 ///
37 /// If the pin is already high, this does *not* return immediately, it'll wait for the
38 /// pin to go low and then high again.
39 async fn wait_for_rising_edge(&mut self) -> Result<(), Self::Error>;
40
41 /// Wait for the pin to undergo a transition from high to low.
42 ///
43 /// If the pin is already low, this does *not* return immediately, it'll wait for the
44 /// pin to go high and then low again.
45 async fn wait_for_falling_edge(&mut self) -> Result<(), Self::Error>;
46
47 /// Wait for the pin to undergo any transition, i.e low to high OR high to low.
48 async fn wait_for_any_edge(&mut self) -> Result<(), Self::Error>;
49}
50
51impl<T: Wait + ?Sized> Wait for &mut T {
52 #[inline]
53 async fn wait_for_high(&mut self) -> Result<(), Self::Error> {
54 T::wait_for_high(self).await
55 }
56
57 #[inline]
58 async fn wait_for_low(&mut self) -> Result<(), Self::Error> {
59 T::wait_for_low(self).await
60 }
61
62 #[inline]
63 async fn wait_for_rising_edge(&mut self) -> Result<(), Self::Error> {
64 T::wait_for_rising_edge(self).await
65 }
66
67 #[inline]
68 async fn wait_for_falling_edge(&mut self) -> Result<(), Self::Error> {
69 T::wait_for_falling_edge(self).await
70 }
71
72 #[inline]
73 async fn wait_for_any_edge(&mut self) -> Result<(), Self::Error> {
74 T::wait_for_any_edge(self).await
75 }
76}
77