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// Copyright 2021 The gd32f1x0-hal authors.
//
// SPDX-License-Identifier: MIT OR Apache-2.0
use crate::pac::{
dbg::ctl0::Timer0Hold, dbg::ctl1::Timer14Hold, Dbg, Timer0, Timer1, Timer13, Timer14, Timer15,
Timer16, Timer2, Timer5,
};
use crate::rcu::{sealed::RcuBus, Clocks, Enable, GetBusFreq, Reset, APB1, APB2};
use crate::time::Hertz;
use core::convert::TryFrom;
use cortex_m::peripheral::syst::SystClkSource;
use cortex_m::peripheral::SYST;
/// Interrupt events
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum Event {
/// Timer timed out / count down ended
Update,
}
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum Error {
/// Timer is canceled
Canceled,
}
pub struct Timer<TIMER> {
pub(crate) timer: TIMER,
pub(crate) clock: Hertz,
}
pub struct CountDownTimer<TIMER> {
timer: TIMER,
clock: Hertz,
}
pub enum DebugHold {
/// Continue running even when stopped for debugging.
Continue,
/// Stop the timer when stopped for debugging.
Stop,
}
impl From<DebugHold> for Timer0Hold {
fn from(hold: DebugHold) -> Self {
match hold {
DebugHold::Continue => Timer0Hold::Continue,
DebugHold::Stop => Timer0Hold::Stop,
}
}
}
impl From<DebugHold> for Timer14Hold {
fn from(hold: DebugHold) -> Self {
match hold {
DebugHold::Continue => Timer14Hold::Continue,
DebugHold::Stop => Timer14Hold::Stop,
}
}
}
impl Timer<SYST> {
pub fn syst(mut syst: SYST, clocks: &Clocks) -> Self {
syst.set_clock_source(SystClkSource::Core);
Self {
timer: syst,
clock: clocks.hclk(),
}
}
/// Configures the SYST timer as a periodic count down timer.
pub fn start_count_down<T>(self, timeout: T) -> CountDownTimer<SYST>
where
T: Into<Hertz>,
{
let Self { timer, clock } = self;
let mut timer = CountDownTimer { timer, clock };
timer.start(timeout);
timer
}
pub fn release(self) -> SYST {
self.timer
}
}
impl CountDownTimer<SYST> {
/// Starts listening for an `event`
pub fn listen(&mut self, event: Event) {
match event {
Event::Update => self.timer.enable_interrupt(),
}
}
/// Stops listening for an `event`
pub fn unlisten(&mut self, event: Event) {
match event {
Event::Update => self.timer.disable_interrupt(),
}
}
/// Resets the counter
pub fn reset(&mut self) {
// According to the Cortex-M3 Generic User Guide, the interrupt request is only generated
// when the counter goes from 1 to 0, so writing zero should not trigger an interrupt
self.timer.clear_current();
}
/// Returns the number of microseconds since the last update event.
/// *NOTE:* This method is not a very good candidate to keep track of time, because
/// it is very easy to lose an update event.
pub fn micros_since(&self) -> u32 {
let reload_value = SYST::get_reload();
let timer_clock = u64::from(self.clock.0);
let ticks = u64::from(reload_value - SYST::get_current());
// It is safe to make this cast since the maximum ticks is (2^24 - 1) and the minimum sysclk
// is 4Mhz, which gives a maximum period of ~4.2 seconds which is < (2^32 - 1) microseconds
u32::try_from(1_000_000 * ticks / timer_clock).unwrap()
}
/// Stops the timer
pub fn stop(mut self) -> Timer<SYST> {
self.timer.disable_counter();
let Self { timer, clock } = self;
Timer { timer, clock }
}
/// Releases the SYST
pub fn release(self) -> SYST {
self.stop().release()
}
/// Configures the timer to have the given timeout and enables it to start counting down.
pub fn start<T>(&mut self, timeout: T)
where
T: Into<Hertz>,
{
let rvr = self.clock.0 / timeout.into().0 - 1;
assert!(rvr < (1 << 24));
self.timer.set_reload(rvr);
self.timer.clear_current();
self.timer.enable_counter();
}
/// Returns whether the timer has finished counting down yet, and resets the flag if so.
pub fn has_elapsed(&mut self) -> bool {
self.timer.has_wrapped()
}
/// Disables the timer.
pub fn cancel(&mut self) -> Result<(), Error> {
if !self.timer.is_counter_enabled() {
return Err(Error::Canceled);
}
self.timer.disable_counter();
Ok(())
}
}
#[cfg(feature = "embedded-hal-02")]
impl embedded_hal_02::timer::CountDown for CountDownTimer<SYST> {
type Time = Hertz;
fn start<T>(&mut self, timeout: T)
where
T: Into<Hertz>,
{
self.start(timeout);
}
fn wait(&mut self) -> nb::Result<(), void::Void> {
if self.has_elapsed() {
Ok(())
} else {
Err(nb::Error::WouldBlock)
}
}
}
#[cfg(feature = "embedded-hal-02")]
impl embedded_hal_02::timer::Cancel for CountDownTimer<SYST> {
type Error = Error;
fn cancel(&mut self) -> Result<(), Self::Error> {
self.cancel()
}
}
#[cfg(feature = "embedded-hal-02")]
impl embedded_hal_02::timer::Periodic for CountDownTimer<SYST> {}
/// Helper methods used by other parts of the HAL, such as PWM.
pub(crate) trait TimerExt {
/// Resets the counter by triggering an update event, disabling the interrupt while doing so.
fn reset_counter(&mut self);
/// Configures the timer with an appropriate prescaler and reload value to count down at the
/// given timeout frequency, assuming it is using the given clock frequency.
fn configure_prescaler_reload(&mut self, timeout: Hertz, clock: Hertz);
}
macro_rules! hal {
($TIMERX:ident: ($timerX:ident, $APBx:ident, $dbg_ctlX:ident, $timerX_hold:ident$(,$master_timerbase:ident)*)) => {
impl Timer<$TIMERX> {
/// Initializes the timer.
pub fn $timerX(timer: $TIMERX, clocks: &Clocks, apb: &mut $APBx) -> Self {
// Enable and reset peripheral to a clean state.
$TIMERX::enable(apb);
$TIMERX::reset(apb);
Self {
timer,
clock: <$TIMERX as RcuBus>::Bus::get_timer_frequency(clocks),
}
}
/// Starts the timer in count down mode at a given frequency.
pub fn start_count_down<T>(self, timeout: T) -> CountDownTimer<$TIMERX>
where
T: Into<Hertz>,
{
let Self { timer, clock } = self;
let mut timer = CountDownTimer { timer, clock };
timer.start(timeout);
timer
}
$(
/// Starts timer in count down mode at a given frequency, and additionally configures
/// the timer's master mode.
pub fn start_master<T>(
self,
timeout: T,
mode: crate::pac::$master_timerbase::ctl1::Mmc,
) -> CountDownTimer<$TIMERX>
where
T: Into<Hertz>,
{
let Self { timer, clock } = self;
let mut timer = CountDownTimer { timer, clock };
timer.timer.ctl1().modify(|_, w| w.mmc().variant(mode));
timer.start(timeout);
timer
}
)?
/// Resets the timer peripheral.
#[inline(always)]
pub fn clocking_reset(&mut self, apb: &mut <$TIMERX as RcuBus>::Bus) {
$TIMERX::reset(apb);
}
/// Configures whether the timer will be stopped when stopping for debugging.
///
/// Stopping timer in debug mode can cause troubles when sampling the signal.
#[inline(always)]
pub fn stop_in_debug(&mut self, dbg: &mut Dbg, hold: DebugHold) {
dbg.$dbg_ctlX().modify(|_, w| w.$timerX_hold().variant(hold.into()));
}
/// Releases the TIMER Peripheral.
pub fn release(self) -> $TIMERX {
// TODO: Disable timer?
self.timer
}
}
impl CountDownTimer<$TIMERX> {
/// Starts listening for an `event`.
pub fn listen(&mut self, event: Event) {
match event {
Event::Update => self.timer.dmainten().modify(|_, w| w.upie().enabled()),
}
}
/// Stops listening for an `event`.
pub fn unlisten(&mut self, event: Event) {
match event {
Event::Update => self.timer.dmainten().modify(|_, w| w.upie().disabled()),
}
}
/// Stops the timer
pub fn stop(self) -> Timer<$TIMERX> {
self.timer.ctl0().modify(|_, w| w.cen().disabled());
let Self { timer, clock } = self;
Timer { timer, clock }
}
/// Returns true if the given `event` interrupt is pending.
pub fn is_pending(&self, event: Event) -> bool {
match event {
Event::Update => self.timer.intf().read().upif().is_update_pending(),
}
}
/// Clears the given event interrupt flag.
pub fn clear_interrupt_flag(&mut self, event: Event) {
match event {
Event::Update => self.timer.intf().modify(|_, w| w.upif().clear()),
}
}
/// Releases the TIMER peripheral.
pub fn release(self) -> $TIMERX {
self.stop().release()
}
/// Returns the number of microseconds since the last update event.
/// *NOTE:* This method is not a very good candidate to keep track of time, because
/// it is very easy to lose an update event.
pub fn micros_since(&self) -> u32 {
let timer_clock = self.clock.0;
let psc = u32::from(self.timer.psc().read().psc().bits());
// freq_divider is always bigger than 0, since (psc + 1) is always less than
// timer_clock
let freq_divider = u64::from(timer_clock / (psc + 1));
let cnt = u64::from(self.timer.cnt().read().cnt().bits());
// It is safe to make this cast, because the maximum timer period in this HAL is
// 1s (1Hz), then 1 second < (2^32 - 1) microseconds
u32::try_from(1_000_000 * cnt / freq_divider).unwrap()
}
/// Resets the counter
pub fn reset(&mut self) {
self.timer.reset_counter();
}
/// Configures the timer to have the given timeout and enables it to start counting down.
pub fn start<T>(&mut self, timeout: T)
where
T: Into<Hertz>,
{
// Pause counter.
self.timer.ctl0().modify(|_, w| w.cen().disabled());
self.timer.configure_prescaler_reload(timeout.into(), self.clock);
// Trigger an update event to load the prescaler value to the clock
self.timer.reset_counter();
// Start counter.
self.timer.ctl0().modify(|_, w| w.cen().enabled());
}
/// Disables the timer.
pub fn cancel(&mut self) -> Result<(), Error> {
let is_counter_enabled = self.timer.ctl0().read().cen().is_enabled();
if !is_counter_enabled {
return Err(Error::Canceled);
}
// Pause counter.
self.timer.ctl0().modify(|_, w| w.cen().disabled());
Ok(())
}
}
impl TimerExt for $TIMERX {
fn reset_counter(&mut self) {
// Sets the UPS bit to prevent an interrupt from being triggered by the UPG bit.
self.ctl0().modify(|_, w| w.ups().counter_only());
self.swevg().write(|w| w.upg().update());
self.ctl0().modify(|_, w| w.ups().any_event());
}
fn configure_prescaler_reload(&mut self, timeout: Hertz, clock: Hertz) {
// Calculate prescaler and reload values.
let (prescaler, auto_reload_value) = compute_prescaler_reload(timeout, clock);
self.psc().write(|w| w.psc().bits(prescaler));
// TODO: Support 32-bit counters
self.car().write(|w| w.car().bits(auto_reload_value.into()));
}
}
#[cfg(feature = "embedded-hal-02")]
impl embedded_hal_02::timer::CountDown for CountDownTimer<$TIMERX> {
type Time = Hertz;
fn start<T>(&mut self, timeout: T)
where
T: Into<Hertz>,
{
self.start(timeout);
}
fn wait(&mut self) -> nb::Result<(), void::Void> {
if !self.is_pending(Event::Update) {
Err(nb::Error::WouldBlock)
} else {
self.clear_interrupt_flag(Event::Update);
Ok(())
}
}
}
#[cfg(feature = "embedded-hal-02")]
impl embedded_hal_02::timer::Cancel for CountDownTimer<$TIMERX> {
type Error = Error;
fn cancel(&mut self) -> Result<(), Self::Error> {
self.cancel()
}
}
#[cfg(feature = "embedded-hal-02")]
impl embedded_hal_02::timer::Periodic for CountDownTimer<$TIMERX> {}
};
}
#[inline(always)]
fn compute_prescaler_reload(freq: Hertz, clock: Hertz) -> (u16, u16) {
let ticks = clock.0 / freq.0;
let psc = u16::try_from((ticks - 1) >> 16).unwrap();
let car = u16::try_from(ticks / u32::from(psc + 1)).unwrap();
(psc, car)
}
hal!(Timer0: (timer0, APB2, ctl0, timer0_hold, timer0));
hal!(Timer1: (timer1, APB1, ctl0, timer1_hold, timer1));
hal!(Timer2: (timer2, APB1, ctl0, timer2_hold, timer1));
hal!(Timer5: (timer5, APB1, ctl0, timer5_hold, timer5));
hal!(Timer13: (timer13, APB1, ctl0, timer13_hold));
hal!(Timer14: (timer14, APB2, ctl1, timer14_hold, timer14));
hal!(Timer15: (timer15, APB2, ctl1, timer15_hold));
hal!(Timer16: (timer16, APB2, ctl1, timer16_hold));