Trait embedded_hal::timer::nb::CountDown

pub trait CountDown {
    type Error: Debug;
    type Time;
    fn start<T>(&mut self, count: T) -> Result<(), Self::Error>
    where
        T: Into<Self::Time>;
    fn wait(&mut self) -> Result<(), Self::Error>;
}

A count down timer

Contract

• self.start(count); block!(self.wait()); MUST block for AT LEAST the time specified by count.

Note that the implementer doesn’t necessarily have to be a downcounting timer; it could also be an upcounting timer as long as the above contract is upheld.

Examples

You can use this timer to create delays

extern crate embedded_hal as hal;
#[macro_use(block)]
extern crate nb;

use hal::timer::nb::CountDown;

fn main() {
    let mut led: Led = {
        // ..
    };
    let mut timer: Timer6 = {
        // ..
    };

    Led.on();
    timer.start(1.s()).unwrap();
    block!(timer.wait()); // blocks for 1 second
    Led.off();
}

Associated Types

type Error: Debug

An enumeration of CountDown errors.

For infallible implementations, will be Infallible

type Time

The unit of time used by this timer

Required methods

fn start<T>(&mut self, count: T) -> Result<(), Self::Error> where
    T: Into<Self::Time>, 

Starts a new count down

fn wait(&mut self) -> Result<(), Self::Error>

Non-blockingly “waits” until the count down finishes

Contract

• If Self: Periodic, the timer will start a new count down right after the last one finishes.
• Otherwise the behavior of calling wait after the last call returned Ok is UNSPECIFIED. Implementers are suggested to panic on this scenario to signal a programmer error.

Implementations on Foreign Types

impl<T: CountDown> CountDown for &mut T

type Error = T::Error

type Time = T::Time

fn start<TIME>(&mut self, count: TIME) -> Result<(), Self::Error> where
    TIME: Into<Self::Time>, 

fn wait(&mut self) -> Result<(), Self::Error>

Implementors