lpc55-hal 0.5.0

Hardware Abstraction Layer (HAL) for the NXP LPC55S6x ARM Cortex-33 microcontrollers
Documentation 
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use core::convert::Infallible;

use nb;
use void::Void;

use crate::{
    peripherals::ctimer::Ctimer, time::Microseconds, traits::wg::timer, typestates::init_state,
};

/// Return the current time elapsed for the timer.
/// If the timer has not started or stopped, this unit may not be accurate.
pub trait Elapsed: timer::CountDown {
    fn elapsed(&self) -> Self::Time;
}

pub struct Timer<TIMER>
where
    TIMER: Ctimer<init_state::Enabled>,
{
    timer: TIMER,
}

impl<TIMER> Timer<TIMER>
where
    TIMER: Ctimer<init_state::Enabled>,
{
    pub fn new(timer: TIMER) -> Self {
        Self { timer }
    }

    pub fn release(self) -> TIMER {
        self.timer
    }
}

type TimeUnits = Microseconds;

impl<TIMER> Elapsed for Timer<TIMER>
where
    TIMER: Ctimer<init_state::Enabled>,
{
    fn elapsed(&self) -> Microseconds {
        Microseconds(self.timer.tc.read().bits())
    }
}

impl<TIMER> timer::CountDown for Timer<TIMER>
where
    TIMER: Ctimer<init_state::Enabled>,
{
    type Time = TimeUnits;

    fn start<T>(&mut self, count: T)
    where
        T: Into<Self::Time>,
    {
        // Match should reset and stop timer, and generate interrupt.
        self.timer
            .mcr
            .modify(|_, w| w.mr0i().set_bit().mr0r().set_bit().mr0s().set_bit());

        // Set match to target time.  Ctimer fixed input 1MHz.
        self.timer.mr[0].write(|w| unsafe { w.bits(count.into().0) });

        // No divsion necessary.
        self.timer.pr.write(|w| unsafe { w.bits(0) });

        // clear interrupt
        self.timer.ir.modify(|_, w| w.mr0int().set_bit());

        // Start timer
        self.timer
            .tcr
            .write(|w| w.crst().clear_bit().cen().set_bit());
    }

    fn wait(&mut self) -> nb::Result<(), Void> {
        if self.timer.ir.read().mr0int().bit_is_set() {
            self.timer
                .tcr
                .write(|w| w.crst().set_bit().cen().clear_bit());
            return Ok(());
        }

        Err(nb::Error::WouldBlock)
    }
}

impl<TIMER> timer::Cancel for Timer<TIMER>
where
    TIMER: Ctimer<init_state::Enabled>,
{
    type Error = Infallible;
    fn cancel(&mut self) -> Result<(), Self::Error> {
        self.timer
            .tcr
            .write(|w| w.crst().set_bit().cen().clear_bit());
        self.timer.ir.write(|w| w.mr0int().set_bit());
        Ok(())
    }
}