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//! Digital I/O.
use core::{convert::From, ops::Not};
#[cfg(feature = "defmt-03")]
use crate::defmt;
/// Error.
pub trait Error: core::fmt::Debug {
/// Convert error to a generic error kind
///
/// By using this method, errors freely defined by HAL implementations
/// can be converted to a set of generic errors upon which generic
/// code can act.
fn kind(&self) -> ErrorKind;
}
impl Error for core::convert::Infallible {
fn kind(&self) -> ErrorKind {
match *self {}
}
}
/// Error kind.
///
/// This represents a common set of operation errors. HAL implementations are
/// free to define more specific or additional error types. However, by providing
/// a mapping to these common errors, generic code can still react to them.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
#[non_exhaustive]
pub enum ErrorKind {
/// A different error occurred. The original error may contain more information.
Other,
}
impl Error for ErrorKind {
#[inline]
fn kind(&self) -> ErrorKind {
*self
}
}
impl core::fmt::Display for ErrorKind {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
match self {
Self::Other => write!(
f,
"A different error occurred. The original error may contain more information"
),
}
}
}
/// Error type trait.
///
/// This just defines the error type, to be used by the other traits.
pub trait ErrorType {
/// Error type
type Error: Error;
}
impl<T: ErrorType + ?Sized> ErrorType for &T {
type Error = T::Error;
}
impl<T: ErrorType + ?Sized> ErrorType for &mut T {
type Error = T::Error;
}
/// Digital output pin state.
///
/// Conversion from `bool` and logical negation are also implemented
/// for this type.
/// ```rust
/// # use embedded_hal::digital::PinState;
/// let state = PinState::from(false);
/// assert_eq!(state, PinState::Low);
/// assert_eq!(!state, PinState::High);
/// ```
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
#[cfg_attr(feature = "defmt-03", derive(defmt::Format))]
pub enum PinState {
/// Low pin state.
Low,
/// High pin state.
High,
}
impl From<bool> for PinState {
#[inline]
fn from(value: bool) -> Self {
match value {
false => PinState::Low,
true => PinState::High,
}
}
}
impl Not for PinState {
type Output = PinState;
#[inline]
fn not(self) -> Self::Output {
match self {
PinState::High => PinState::Low,
PinState::Low => PinState::High,
}
}
}
impl From<PinState> for bool {
#[inline]
fn from(value: PinState) -> bool {
match value {
PinState::Low => false,
PinState::High => true,
}
}
}
/// Single digital push-pull output pin.
pub trait OutputPin: ErrorType {
/// Drives the pin low.
///
/// *NOTE* the actual electrical state of the pin may not actually be low, e.g. due to external
/// electrical sources.
fn set_low(&mut self) -> Result<(), Self::Error>;
/// Drives the pin high.
///
/// *NOTE* the actual electrical state of the pin may not actually be high, e.g. due to external
/// electrical sources.
fn set_high(&mut self) -> Result<(), Self::Error>;
/// Drives the pin high or low depending on the provided value.
///
/// *NOTE* the actual electrical state of the pin may not actually be high or low, e.g. due to external
/// electrical sources.
#[inline]
fn set_state(&mut self, state: PinState) -> Result<(), Self::Error> {
match state {
PinState::Low => self.set_low(),
PinState::High => self.set_high(),
}
}
}
impl<T: OutputPin + ?Sized> OutputPin for &mut T {
#[inline]
fn set_low(&mut self) -> Result<(), Self::Error> {
T::set_low(self)
}
#[inline]
fn set_high(&mut self) -> Result<(), Self::Error> {
T::set_high(self)
}
#[inline]
fn set_state(&mut self, state: PinState) -> Result<(), Self::Error> {
T::set_state(self, state)
}
}
/// Push-pull output pin that can read its output state.
pub trait StatefulOutputPin: OutputPin {
/// Is the pin in drive high mode?
///
/// *NOTE* this does *not* read the electrical state of the pin.
fn is_set_high(&mut self) -> Result<bool, Self::Error>;
/// Is the pin in drive low mode?
///
/// *NOTE* this does *not* read the electrical state of the pin.
fn is_set_low(&mut self) -> Result<bool, Self::Error>;
/// Toggle pin output.
fn toggle(&mut self) -> Result<(), Self::Error> {
let was_low: bool = self.is_set_low()?;
self.set_state(PinState::from(was_low))
}
}
impl<T: StatefulOutputPin + ?Sized> StatefulOutputPin for &mut T {
#[inline]
fn is_set_high(&mut self) -> Result<bool, Self::Error> {
T::is_set_high(self)
}
#[inline]
fn is_set_low(&mut self) -> Result<bool, Self::Error> {
T::is_set_low(self)
}
#[inline]
fn toggle(&mut self) -> Result<(), Self::Error> {
T::toggle(self)
}
}
/// Single digital input pin.
pub trait InputPin: ErrorType {
/// Is the input pin high?
fn is_high(&mut self) -> Result<bool, Self::Error>;
/// Is the input pin low?
fn is_low(&mut self) -> Result<bool, Self::Error>;
}
impl<T: InputPin + ?Sized> InputPin for &mut T {
#[inline]
fn is_high(&mut self) -> Result<bool, Self::Error> {
T::is_high(self)
}
#[inline]
fn is_low(&mut self) -> Result<bool, Self::Error> {
T::is_low(self)
}
}