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time: replace dyn clock/alarm with a global Driver trait

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This commit is contained in:
Dario Nieuwenhuis 2021-08-03 22:08:13 +02:00
parent a4c0ee6df7
commit 0ea6a2d890
47 changed files with 663 additions and 814 deletions
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2
.github/workflows/rust.yml vendored
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@ -77,7 +77,7 @@ jobs:
features: stm32l476vg,defmt
- package: embassy-stm32
target: thumbv6m-none-eabi
features: stm32l053r8,defmt
features: stm32l072cz,defmt
- package: examples/stm32f4
target: thumbv7em-none-eabi
- package: examples/stm32l4

13
embassy-macros/src/chip/nrf.rs
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@ -3,22 +3,9 @@ use proc_macro2::TokenStream;
use quote::quote;
pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream {
let embassy_path = embassy_prefix.append("embassy").path();
let embassy_nrf_path = embassy_prefix.append("embassy_nrf").path();
quote!(
use #embassy_nrf_path::{interrupt, peripherals, rtc};
let p = #embassy_nrf_path::init(#config);
let mut rtc = rtc::RTC::new(unsafe { <peripherals::RTC1 as #embassy_path::util::Steal>::steal() }, interrupt::take!(RTC1));
let rtc = unsafe { make_static(&mut rtc) };
rtc.start();
let mut alarm = rtc.alarm0();
unsafe { #embassy_path::time::set_clock(rtc) };
let alarm = unsafe { make_static(&mut alarm) };
executor.set_alarm(alarm);
)
}

8
embassy-macros/src/chip/rp.rs
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@ -3,16 +3,8 @@ use proc_macro2::TokenStream;
use quote::quote;
pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream {
let embassy_path = embassy_prefix.append("embassy").path();
let embassy_rp_path = embassy_prefix.append("embassy_rp").path();
quote!(
use #embassy_rp_path::{interrupt, peripherals};
let p = #embassy_rp_path::init(#config);
let alarm = unsafe { <#embassy_rp_path::peripherals::TIMER_ALARM0 as #embassy_path::util::Steal>::steal() };
let mut alarm = #embassy_rp_path::timer::Alarm::new(alarm);
let alarm = unsafe { make_static(&mut alarm) };
executor.set_alarm(alarm);
)
}

17
embassy-macros/src/chip/stm32.rs
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@ -3,26 +3,9 @@ use proc_macro2::TokenStream;
use quote::quote;
pub fn generate(embassy_prefix: &ModulePrefix, config: syn::Expr) -> TokenStream {
let embassy_path = embassy_prefix.append("embassy").path();
let embassy_stm32_path = embassy_prefix.append("embassy_stm32").path();
quote!(
use #embassy_stm32_path::{interrupt, peripherals, clock::Clock, time::Hertz};
let p = #embassy_stm32_path::init(#config);
let mut c = Clock::new(
unsafe { <peripherals::TIM3 as embassy::util::Steal>::steal() },
interrupt::take!(TIM3),
);
let clock = unsafe { make_static(&mut c) };
clock.start();
let mut alarm = clock.alarm1();
unsafe { #embassy_path::time::set_clock(clock) };
let alarm = unsafe { make_static(&mut alarm) };
executor.set_alarm(alarm);
)
}

8
embassy-nrf/src/lib.rs
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@ -23,6 +23,8 @@ compile_error!("No chip feature activated. You must activate exactly one of the
pub(crate) mod fmt;
pub(crate) mod util;
mod time_driver;
pub mod buffered_uarte;
pub mod gpio;
pub mod gpiote;
@ -32,7 +34,6 @@ pub mod pwm;
#[cfg(feature = "nrf52840")]
pub mod qspi;
pub mod rng;
pub mod rtc;
#[cfg(not(feature = "nrf52820"))]
pub mod saadc;
pub mod spim;
@ -160,7 +161,10 @@ pub fn init(config: config::Config) -> Peripherals {
while r.events_lfclkstarted.read().bits() == 0 {}
// Init GPIOTE
crate::gpiote::init(config.gpiote_interrupt_priority);
gpiote::init(config.gpiote_interrupt_priority);
// init RTC time driver
time_driver::init();
peripherals
}

251
embassy-nrf/src/rtc.rs → embassy-nrf/src/time_driver.rs
View File

@ -1,13 +1,17 @@
use core::cell::Cell;
use core::sync::atomic::{compiler_fence, AtomicU32, Ordering};
use core::sync::atomic::{compiler_fence, AtomicU32, AtomicU8, Ordering};
use core::{mem, ptr};
use critical_section::CriticalSection;
use embassy::interrupt::InterruptExt;
use embassy::time::Clock;
use embassy::util::{CriticalSectionMutex as Mutex, Unborrow};
use embassy::interrupt::{Interrupt, InterruptExt};
use embassy::time::driver::{AlarmHandle, Driver};
use embassy::util::CriticalSectionMutex as Mutex;
use crate::interrupt::Interrupt;
use crate::interrupt;
use crate::pac;
use crate::{interrupt, peripherals};
fn rtc() -> &'static pac::rtc0::RegisterBlock {
unsafe { &*pac::RTC1::ptr() }
}
// RTC timekeeping works with something we call "periods", which are time intervals
// of 2^23 ticks. The RTC counter value is 24 bits, so one "overflow cycle" is 2 periods.
@ -57,46 +61,45 @@ mod test {
struct AlarmState {
timestamp: Cell<u64>,
callback: Cell<Option<(fn(*mut ()), *mut ())>>,
// This is really a Option<(fn(*mut ()), *mut ())>
// but fn pointers aren't allowed in const yet
callback: Cell<*const ()>,
ctx: Cell<*mut ()>,
}
unsafe impl Send for AlarmState {}
impl AlarmState {
fn new() -> Self {
const fn new() -> Self {
Self {
timestamp: Cell::new(u64::MAX),
callback: Cell::new(None),
callback: Cell::new(ptr::null()),
ctx: Cell::new(ptr::null_mut()),
}
}
}
const ALARM_COUNT: usize = 3;
pub struct RTC<T: Instance> {
rtc: T,
irq: T::Interrupt,
struct State {
/// Number of 2^23 periods elapsed since boot.
period: AtomicU32,
alarm_count: AtomicU8,
/// Timestamp at which to fire alarm. u64::MAX if no alarm is scheduled.
alarms: Mutex<[AlarmState; ALARM_COUNT]>,
}
unsafe impl<T: Instance> Send for RTC<T> {}
unsafe impl<T: Instance> Sync for RTC<T> {}
const ALARM_STATE_NEW: AlarmState = AlarmState::new();
static STATE: State = State {
period: AtomicU32::new(0),
alarm_count: AtomicU8::new(0),
alarms: Mutex::new([ALARM_STATE_NEW; ALARM_COUNT]),
};
impl<T: Instance> RTC<T> {
pub fn new(rtc: T, irq: T::Interrupt) -> Self {
Self {
rtc,
irq,
period: AtomicU32::new(0),
alarms: Mutex::new([AlarmState::new(), AlarmState::new(), AlarmState::new()]),
}
}
pub fn start(&'static self) {
let r = self.rtc.regs();
impl State {
fn init(&'static self) {
let r = rtc();
r.cc[3].write(|w| unsafe { w.bits(0x800000) });
r.intenset.write(|w| {
@ -111,17 +114,11 @@ impl<T: Instance> RTC<T> {
// Wait for clear
while r.counter.read().bits() != 0 {}
self.irq.set_handler(|ptr| unsafe {
let this = &*(ptr as *const () as *const Self);
this.on_interrupt();
});
self.irq.set_handler_context(self as *const _ as *mut _);
self.irq.unpend();
self.irq.enable();
unsafe { interrupt::RTC1::steal() }.enable();
}
fn on_interrupt(&self) {
let r = self.rtc.regs();
let r = rtc();
if r.events_ovrflw.read().bits() == 1 {
r.events_ovrflw.write(|w| w);
self.next_period();
@ -144,7 +141,7 @@ impl<T: Instance> RTC<T> {
fn next_period(&self) {
critical_section::with(|cs| {
let r = self.rtc.regs();
let r = rtc();
let period = self.period.fetch_add(1, Ordering::Relaxed) + 1;
let t = (period as u64) << 23;
@ -152,38 +149,77 @@ impl<T: Instance> RTC<T> {
let alarm = &self.alarms.borrow(cs)[n];
let at = alarm.timestamp.get();
let diff = at - t;
if diff < 0xc00000 {
r.cc[n].write(|w| unsafe { w.bits(at as u32 & 0xFFFFFF) });
if at < t + 0xc00000 {
// just enable it. `set_alarm` has already set the correct CC val.
r.intenset.write(|w| unsafe { w.bits(compare_n(n)) });
}
}
})
}
fn now(&self) -> u64 {
// `period` MUST be read before `counter`, see comment at the top for details.
let period = self.period.load(Ordering::Relaxed);
compiler_fence(Ordering::Acquire);
let counter = rtc().counter.read().bits();
calc_now(period, counter)
}
fn get_alarm<'a>(&'a self, cs: CriticalSection<'a>, alarm: AlarmHandle) -> &'a AlarmState {
// safety: we're allowed to assume the AlarmState is created by us, and
// we never create one that's out of bounds.
unsafe { self.alarms.borrow(cs).get_unchecked(alarm.id() as usize) }
}
fn trigger_alarm(&self, n: usize, cs: CriticalSection) {
let r = self.rtc.regs();
let r = rtc();
r.intenclr.write(|w| unsafe { w.bits(compare_n(n)) });
let alarm = &self.alarms.borrow(cs)[n];
alarm.timestamp.set(u64::MAX);
// Call after clearing alarm, so the callback can set another alarm.
if let Some((f, ctx)) = alarm.callback.get() {
f(ctx);
// safety:
// - we can ignore the possiblity of `f` being unset (null) because of the safety contract of `allocate_alarm`.
// - other than that we only store valid function pointers into alarm.callback
let f: fn(*mut ()) = unsafe { mem::transmute(alarm.callback.get()) };
f(alarm.ctx.get());
}
fn allocate_alarm(&self) -> Option<AlarmHandle> {
let id = self
.alarm_count
.fetch_update(Ordering::AcqRel, Ordering::Acquire, |x| {
if x < ALARM_COUNT as u8 {
Some(x + 1)
} else {
None
}
});
match id {
Ok(id) => Some(unsafe { AlarmHandle::new(id) }),
Err(_) => None,
}
}
fn set_alarm_callback(&self, n: usize, callback: fn(*mut ()), ctx: *mut ()) {
fn set_alarm_callback(&self, alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
critical_section::with(|cs| {
let alarm = &self.alarms.borrow(cs)[n];
alarm.callback.set(Some((callback, ctx)));
let alarm = self.get_alarm(cs, alarm);
// safety: it's OK to transmute a fn pointer into a raw pointer
let callback_ptr: *const () = unsafe { mem::transmute(callback) };
alarm.callback.set(callback_ptr);
alarm.ctx.set(ctx);
})
}
fn set_alarm(&self, n: usize, timestamp: u64) {
fn set_alarm(&self, alarm: AlarmHandle, timestamp: u64) {
critical_section::with(|cs| {
let alarm = &self.alarms.borrow(cs)[n];
let n = alarm.id() as _;
let alarm = self.get_alarm(cs, alarm);
alarm.timestamp.set(timestamp);
let t = self.now();
@ -194,25 +230,30 @@ impl<T: Instance> RTC<T> {
return;
}
let r = self.rtc.regs();
let r = rtc();
// If it hasn't triggered yet, setup it in the compare channel.
// Write the CC value regardless of whether we're going to enable it now or not.
// This way, when we enable it later, the right value is already set.
// nrf52 docs say:
// If the COUNTER is N, writing N or N+1 to a CC register may not trigger a COMPARE event.
// To workaround this, we never write a timestamp smaller than N+3.
// N+2 is not safe because rtc can tick from N to N+1 between calling now() and writing cc.
//
// It is impossible for rtc to tick more than once because
// - this code takes less time than 1 tick
// - it runs with interrupts disabled so nothing else can preempt it.
//
// This means that an alarm can be delayed for up to 2 ticks (from t+1 to t+3), but this is allowed
// by the Alarm trait contract. What's not allowed is triggering alarms *before* their scheduled time,
// and we don't do that here.
let safe_timestamp = timestamp.max(t + 3);
r.cc[n].write(|w| unsafe { w.bits(safe_timestamp as u32 & 0xFFFFFF) });
let diff = timestamp - t;
if diff < 0xc00000 {
// nrf52 docs say:
// If the COUNTER is N, writing N or N+1 to a CC register may not trigger a COMPARE event.
// To workaround this, we never write a timestamp smaller than N+3.
// N+2 is not safe because rtc can tick from N to N+1 between calling now() and writing cc.
//
// It is impossible for rtc to tick more than once because
// - this code takes less time than 1 tick
// - it runs with interrupts disabled so nothing else can preempt it.
//
// This means that an alarm can be delayed for up to 2 ticks (from t+1 to t+3), but this is allowed
// by the Alarm trait contract. What's not allowed is triggering alarms *before* their scheduled time,
// and we don't do that here.
let safe_timestamp = timestamp.max(t + 3);
r.cc[n].write(|w| unsafe { w.bits(safe_timestamp as u32 & 0xFFFFFF) });
r.intenset.write(|w| unsafe { w.bits(compare_n(n)) });
} else {
// If it's too far in the future, don't setup the compare channel yet.
@ -221,74 +262,34 @@ impl<T: Instance> RTC<T> {
}
})
}
}
pub fn alarm0(&'static self) -> Alarm<T> {
Alarm { n: 0, rtc: self }
struct RtcDriver;
embassy::time_driver_impl!(RtcDriver);
impl Driver for RtcDriver {
fn now() -> u64 {
STATE.now()
}
pub fn alarm1(&'static self) -> Alarm<T> {
Alarm { n: 1, rtc: self }
unsafe fn allocate_alarm() -> Option<AlarmHandle> {
STATE.allocate_alarm()
}
pub fn alarm2(&'static self) -> Alarm<T> {
Alarm { n: 2, rtc: self }
fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
STATE.set_alarm_callback(alarm, callback, ctx)
}
fn set_alarm(alarm: AlarmHandle, timestamp: u64) {
STATE.set_alarm(alarm, timestamp)
}
}
impl<T: Instance> embassy::time::Clock for RTC<T> {
fn now(&self) -> u64 {
// `period` MUST be read before `counter`, see comment at the top for details.
let period = self.period.load(Ordering::Relaxed);
compiler_fence(Ordering::Acquire);
let counter = self.rtc.regs().counter.read().bits();
calc_now(period, counter)
}
#[interrupt]
fn RTC1() {
STATE.on_interrupt()
}
pub struct Alarm<T: Instance> {
n: usize,
rtc: &'static RTC<T>,
pub(crate) fn init() {
STATE.init()
}
impl<T: Instance> embassy::time::Alarm for Alarm<T> {
fn set_callback(&self, callback: fn(*mut ()), ctx: *mut ()) {
self.rtc.set_alarm_callback(self.n, callback, ctx);
}
fn set(&self, timestamp: u64) {
self.rtc.set_alarm(self.n, timestamp);
}
fn clear(&self) {
self.rtc.set_alarm(self.n, u64::MAX);
}
}
mod sealed {
use super::*;
pub trait Instance {
fn regs(&self) -> &pac::rtc0::RegisterBlock;
}
}
macro_rules! impl_instance {
($type:ident, $irq:ident) => {
impl sealed::Instance for peripherals::$type {
fn regs(&self) -> &pac::rtc0::RegisterBlock {
unsafe { &*pac::$type::ptr() }
}
}
impl Instance for peripherals::$type {
type Interrupt = interrupt::$irq;
}
};
}
/// Implemented by all RTC instances.
pub trait Instance: Unborrow<Target = Self> + sealed::Instance + 'static {
/// The interrupt associated with this RTC instance.
type Interrupt: Interrupt;
}
impl_instance!(RTC0, RTC0);
impl_instance!(RTC1, RTC1);
#[cfg(any(feature = "nrf52832", feature = "nrf52833", feature = "nrf52840"))]
impl_instance!(RTC2, RTC2);

2
embassy-rp/Cargo.toml
View File

@ -22,7 +22,7 @@ defmt-error = [ ]
embassy = { version = "0.1.0", path = "../embassy", features = [ "time-tick-1mhz" ] }
embassy-hal-common = {version = "0.1.0", path = "../embassy-hal-common" }
embassy-macros = { version = "0.1.0", path = "../embassy-macros", features = ["rp"]}
atomic-polyfill = { version = "0.1.2" }
defmt = { version = "0.2.0", optional = true }
log = { version = "0.4.11", optional = true }
cortex-m-rt = "0.6.13"

5
embassy-rp/src/lib.rs
View File

@ -69,11 +69,6 @@ embassy_hal_common::peripherals! {
SPI0,
SPI1,
TIMER_ALARM0,
TIMER_ALARM1,
TIMER_ALARM2,
TIMER_ALARM3,
DMA_CH0,
DMA_CH1,
DMA_CH2,

72
embassy-rp/src/timer.rs
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@ -1,6 +1,8 @@
use atomic_polyfill::{AtomicU8, Ordering};
use core::cell::Cell;
use critical_section::CriticalSection;
use embassy::interrupt::{Interrupt, InterruptExt};
use embassy::time::driver::{AlarmHandle, Driver};
use embassy::util::CriticalSectionMutex as Mutex;
use crate::{interrupt, pac};
@ -18,6 +20,7 @@ const DUMMY_ALARM: AlarmState = AlarmState {
};
static ALARMS: Mutex<[AlarmState; ALARM_COUNT]> = Mutex::new([DUMMY_ALARM; ALARM_COUNT]);
static NEXT_ALARM: AtomicU8 = AtomicU8::new(0);
fn now() -> u64 {
loop {
@ -32,60 +35,39 @@ fn now() -> u64 {
}
}
struct Timer;
impl embassy::time::Clock for Timer {
fn now(&self) -> u64 {
struct TimerDriver;
embassy::time_driver_impl!(TimerDriver);
impl Driver for TimerDriver {
fn now() -> u64 {
now()
}
}
pub trait AlarmInstance {
fn alarm_num(&self) -> usize;
}
unsafe fn allocate_alarm() -> Option<AlarmHandle> {
let id = NEXT_ALARM.fetch_update(Ordering::AcqRel, Ordering::Acquire, |x| {
if x < ALARM_COUNT as u8 {
Some(x + 1)
} else {
None
}
});
impl AlarmInstance for crate::peripherals::TIMER_ALARM0 {
fn alarm_num(&self) -> usize {
0
match id {
Ok(id) => Some(AlarmHandle::new(id)),
Err(_) => None,
}
}
}
impl AlarmInstance for crate::peripherals::TIMER_ALARM1 {
fn alarm_num(&self) -> usize {
1
}
}
impl AlarmInstance for crate::peripherals::TIMER_ALARM2 {
fn alarm_num(&self) -> usize {
2
}
}
impl AlarmInstance for crate::peripherals::TIMER_ALARM3 {
fn alarm_num(&self) -> usize {
3
}
}
pub struct Alarm<T: AlarmInstance> {
inner: T,
}
impl<T: AlarmInstance> Alarm<T> {
pub fn new(inner: T) -> Self {
Self { inner }
}
}
impl<T: AlarmInstance> embassy::time::Alarm for Alarm<T> {
fn set_callback(&self, callback: fn(*mut ()), ctx: *mut ()) {
let n = self.inner.alarm_num();
fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
let n = alarm.id() as usize;
critical_section::with(|cs| {
let alarm = &ALARMS.borrow(cs)[n];
alarm.callback.set(Some((callback, ctx)));
})
}
fn set(&self, timestamp: u64) {
let n = self.inner.alarm_num();
fn set_alarm(alarm: AlarmHandle, timestamp: u64) {
let n = alarm.id() as usize;
critical_section::with(|cs| {
let alarm = &ALARMS.borrow(cs)[n];
alarm.timestamp.set(timestamp);
@ -105,10 +87,6 @@ impl<T: AlarmInstance> embassy::time::Alarm for Alarm<T> {
}
})
}
fn clear(&self) {
self.set(u64::MAX);
}
}
fn check_alarm(n: usize) {
@ -162,8 +140,6 @@ pub unsafe fn init() {
interrupt::TIMER_IRQ_1::steal().enable();
interrupt::TIMER_IRQ_2::steal().enable();
interrupt::TIMER_IRQ_3::steal().enable();
embassy::time::set_clock(&Timer);
}
#[interrupt]

38
embassy-std/src/lib.rs
View File

@ -1,6 +1,6 @@
use embassy::executor::{raw, Spawner};
use embassy::time::driver::{AlarmHandle, Driver};
use embassy::time::TICKS_PER_SECOND;
use embassy::time::{Alarm, Clock};
use std::marker::PhantomData;
use std::mem::MaybeUninit;
use std::ptr;
@ -8,28 +8,31 @@ use std::sync::{Condvar, Mutex};
use std::time::{Duration as StdDuration, Instant as StdInstant};
static mut CLOCK_ZERO: MaybeUninit<StdInstant> = MaybeUninit::uninit();
struct StdClock;
impl Clock for StdClock {
fn now(&self) -> u64 {
static mut ALARM_AT: u64 = u64::MAX;
static mut NEXT_ALARM_ID: u8 = 0;
struct TimeDriver;
embassy::time_driver_impl!(TimeDriver);
impl Driver for TimeDriver {
fn now() -> u64 {
let zero = unsafe { CLOCK_ZERO.as_ptr().read() };
let dur = StdInstant::now().duration_since(zero);
dur.as_secs() * (TICKS_PER_SECOND as u64)
+ (dur.subsec_nanos() as u64) * (TICKS_PER_SECOND as u64) / 1_000_000_000
}
}
static mut ALARM_AT: u64 = u64::MAX;
pub struct StdAlarm;
impl Alarm for StdAlarm {
fn set_callback(&self, _callback: fn(*mut ()), _ctx: *mut ()) {}
fn set(&self, timestamp: u64) {
unsafe { ALARM_AT = timestamp }
unsafe fn allocate_alarm() -> Option<AlarmHandle> {
let r = NEXT_ALARM_ID;
NEXT_ALARM_ID += 1;
Some(AlarmHandle::new(r))
}
fn clear(&self) {
unsafe { ALARM_AT = u64::MAX }
fn set_alarm_callback(_alarm: AlarmHandle, _callback: fn(*mut ()), _ctx: *mut ()) {}
fn set_alarm(_alarm: AlarmHandle, timestamp: u64) {
unsafe { ALARM_AT = ALARM_AT.min(timestamp) }
}
}
@ -53,7 +56,8 @@ impl Signaler {
if alarm_at == u64::MAX {
signaled = self.condvar.wait(signaled).unwrap();
} else {
let now = StdClock.now();
unsafe { ALARM_AT = u64::MAX };
let now = TimeDriver::now();
if now >= alarm_at {
break;
}
@ -92,7 +96,6 @@ impl Executor {
pub fn new() -> Self {
unsafe {
CLOCK_ZERO.as_mut_ptr().write(StdInstant::now());
embassy::time::set_clock(&StdClock);
}
Self {
@ -107,7 +110,6 @@ impl Executor {
/// This function never returns.
pub fn run(&'static mut self, init: impl FnOnce(Spawner)) -> ! {
self.inner.set_signal_ctx(&self.signaler as *const _ as _);
self.inner.set_alarm(&StdAlarm);
init(unsafe { self.inner.spawner() });

372
embassy-stm32/src/clock.rs
View File

@ -1,372 +0,0 @@
#![macro_use]
use core::cell::Cell;
use core::convert::TryInto;
use core::sync::atomic::{compiler_fence, Ordering};
use atomic_polyfill::AtomicU32;
use embassy::interrupt::InterruptExt;
use embassy::time::{Clock as EmbassyClock, TICKS_PER_SECOND};
use crate::interrupt::{CriticalSection, Interrupt, Mutex};
use crate::pac::timer::TimGp16;
use crate::peripherals;
use crate::rcc::RccPeripheral;
use crate::time::Hertz;
// Clock timekeeping works with something we call "periods", which are time intervals
// of 2^15 ticks. The Clock counter value is 16 bits, so one "overflow cycle" is 2 periods.
//
// A `period` count is maintained in parallel to the Timer hardware `counter`, like this:
// - `period` and `counter` start at 0
// - `period` is incremented on overflow (at counter value 0)
// - `period` is incremented "midway" between overflows (at counter value 0x8000)
//
// Therefore, when `period` is even, counter is in 0..0x7FFF. When odd, counter is in 0x8000..0xFFFF
// This allows for now() to return the correct value even if it races an overflow.
//
// To get `now()`, `period` is read first, then `counter` is read. If the counter value matches
// the expected range for the `period` parity, we're done. If it doesn't, this means that
// a new period start has raced us between reading `period` and `counter`, so we assume the `counter` value
// corresponds to the next period.
//
// `period` is a 32bit integer, so It overflows on 2^32 * 2^15 / 32768 seconds of uptime, which is 136 years.
fn calc_now(period: u32, counter: u16) -> u64 {
((period as u64) << 15) + ((counter as u32 ^ ((period & 1) << 15)) as u64)
}
struct AlarmState {
timestamp: Cell<u64>,
#[allow(clippy::type_complexity)]
callback: Cell<Option<(fn(*mut ()), *mut ())>>,
}
impl AlarmState {
fn new() -> Self {
Self {
timestamp: Cell::new(u64::MAX),
callback: Cell::new(None),
}
}
}
const ALARM_COUNT: usize = 3;
/// Clock timer that can be used by the executor and to set alarms.
///
/// It can work with Timers 2, 3, 4, 5. This timer works internally with a unit of 2^15 ticks, which
/// means that if a call to [`embassy::time::Clock::now`] is blocked for that amount of ticks the
/// returned value will be wrong (an old value). The current default tick rate is 32768 ticks per
/// second.
pub struct Clock<T: Instance> {
_inner: T,
irq: T::Interrupt,
/// Number of 2^23 periods elapsed since boot.
period: AtomicU32,
/// Timestamp at which to fire alarm. u64::MAX if no alarm is scheduled.
alarms: Mutex<[AlarmState; ALARM_COUNT]>,
}
impl<T: Instance> Clock<T> {
pub fn new(peripheral: T, irq: T::Interrupt) -> Self {
Self {
_inner: peripheral,
irq,
period: AtomicU32::new(0),
alarms: Mutex::new([AlarmState::new(), AlarmState::new(), AlarmState::new()]),
}
}
pub fn start(&'static self) {
let inner = T::inner();
T::enable();
T::reset();
let timer_freq = T::frequency();
// NOTE(unsafe) Critical section to use the unsafe methods
critical_section::with(|_| {
unsafe {
inner.prepare(timer_freq);
}
self.irq.set_handler_context(self as *const _ as *mut _);
self.irq.set_handler(|ptr| unsafe {
let this = &*(ptr as *const () as *const Self);
this.on_interrupt();
});
self.irq.unpend();
self.irq.enable();
unsafe {
inner.start_counter();
}
})
}
fn on_interrupt(&self) {
let inner = T::inner();
// NOTE(unsafe) Use critical section to access the methods
// XXX: reduce the size of this critical section ?
critical_section::with(|cs| unsafe {
if inner.overflow_interrupt_status() {
inner.overflow_clear_flag();
self.next_period();
}
// Half overflow
if inner.compare_interrupt_status(0) {
inner.compare_clear_flag(0);
self.next_period();
}
for n in 1..=ALARM_COUNT {
if inner.compare_interrupt_status(n) {
inner.compare_clear_flag(n);
self.trigger_alarm(n, cs);
}
}
})
}
fn next_period(&self) {
let inner = T::inner();
let period = self.period.fetch_add(1, Ordering::Relaxed) + 1;
let t = (period as u64) << 15;
critical_section::with(move |cs| {
for n in 1..=ALARM_COUNT {
let alarm = &self.alarms.borrow(cs)[n - 1];
let at = alarm.timestamp.get();
let diff = at - t;
if diff < 0xc000 {
inner.set_compare(n, at as u16);
// NOTE(unsafe) We're in a critical section
unsafe {
inner.set_compare_interrupt(n, true);
}
}
}
})
}
fn trigger_alarm(&self, n: usize, cs: CriticalSection) {
let inner = T::inner();
// NOTE(unsafe) We have a critical section
unsafe {
inner.set_compare_interrupt(n, false);
}
let alarm = &self.alarms.borrow(cs)[n - 1];
alarm.timestamp.set(u64::MAX);
// Call after clearing alarm, so the callback can set another alarm.
if let Some((f, ctx)) = alarm.callback.get() {
f(ctx);
}
}
fn set_alarm_callback(&self, n: usize, callback: fn(*mut ()), ctx: *mut ()) {
critical_section::with(|cs| {
let alarm = &self.alarms.borrow(cs)[n - 1];
alarm.callback.set(Some((callback, ctx)));
})
}
fn set_alarm(&self, n: usize, timestamp: u64) {
critical_section::with(|cs| {
let inner = T::inner();
let alarm = &self.alarms.borrow(cs)[n - 1];
alarm.timestamp.set(timestamp);
let t = self.now();
if timestamp <= t {
self.trigger_alarm(n, cs);
return;
}
let diff = timestamp - t;
if diff < 0xc000 {
let safe_timestamp = timestamp.max(t + 3);
inner.set_compare(n, safe_timestamp as u16);
// NOTE(unsafe) We're in a critical section
unsafe {
inner.set_compare_interrupt(n, true);
}
} else {
unsafe {
inner.set_compare_interrupt(n, false);
}
}
})
}
pub fn alarm1(&'static self) -> Alarm<T> {
Alarm { n: 1, rtc: self }
}
pub fn alarm2(&'static self) -> Alarm<T> {
Alarm { n: 2, rtc: self }
}
pub fn alarm3(&'static self) -> Alarm<T> {
Alarm { n: 3, rtc: self }
}
}
impl<T: Instance> EmbassyClock for Clock<T> {
fn now(&self) -> u64 {
let inner = T::inner();
let period = self.period.load(Ordering::Relaxed);
compiler_fence(Ordering::Acquire);
let counter = inner.counter();
calc_now(period, counter)
}
}
pub struct Alarm<T: Instance> {
n: usize,
rtc: &'static Clock<T>,
}
impl<T: Instance> embassy::time::Alarm for Alarm<T> {
fn set_callback(&self, callback: fn(*mut ()), ctx: *mut ()) {
self.rtc.set_alarm_callback(self.n, callback, ctx);
}
fn set(&self, timestamp: u64) {
self.rtc.set_alarm(self.n, timestamp);
}
fn clear(&self) {
self.rtc.set_alarm(self.n, u64::MAX);
}
}
pub struct TimerInner(pub(crate) TimGp16);
impl TimerInner {
unsafe fn prepare(&self, timer_freq: Hertz) {
self.stop_and_reset();
let psc = timer_freq.0 / TICKS_PER_SECOND as u32 - 1;
let psc: u16 = psc.try_into().unwrap();
self.set_psc_arr(psc, u16::MAX);
// Mid-way point
self.set_compare(0, 0x8000);
self.set_compare_interrupt(0, true);
}
unsafe fn start_counter(&self) {
self.0.cr1().modify(|w| w.set_cen(true));
}
unsafe fn stop_and_reset(&self) {
let regs = self.0;
regs.cr1().modify(|w| w.set_cen(false));
regs.cnt().write(|w| w.set_cnt(0));
}
fn overflow_interrupt_status(&self) -> bool {
// NOTE(unsafe) Atomic read with no side-effects
unsafe { self.0.sr().read().uif() }
}
unsafe fn overflow_clear_flag(&self) {
self.0.sr().modify(|w| w.set_uif(false));
}
unsafe fn set_psc_arr(&self, psc: u16, arr: u16) {
use crate::pac::timer::vals::Urs;
let regs = self.0;
regs.psc().write(|w| w.set_psc(psc));
regs.arr().write(|w| w.set_arr(arr));
// Set URS, generate update and clear URS
regs.cr1().modify(|w| w.set_urs(Urs::COUNTERONLY));
regs.egr().write(|w| w.set_ug(true));
regs.cr1().modify(|w| w.set_urs(Urs::ANYEVENT));
}
fn compare_interrupt_status(&self, n: usize) -> bool {
if n > 3 {
false
} else {
// NOTE(unsafe) Atomic read with no side-effects
unsafe { self.0.sr().read().ccif(n) }
}
}
unsafe fn compare_clear_flag(&self, n: usize) {
if n > 3 {
return;
}
self.0.sr().modify(|w| w.set_ccif(n, false));
}
fn set_compare(&self, n: usize, value: u16) {
if n > 3 {
return;
}
// NOTE(unsafe) Atomic write
unsafe {
self.0.ccr(n).write(|w| w.set_ccr(value));
}
}
unsafe fn set_compare_interrupt(&self, n: usize, enable: bool) {
if n > 3 {
return;
}
self.0.dier().modify(|w| w.set_ccie(n, enable));
}
fn counter(&self) -> u16 {
// NOTE(unsafe) Atomic read with no side-effects
unsafe { self.0.cnt().read().cnt() }
}
}
// ------------------------------------------------------
pub(crate) mod sealed {
use super::*;
pub trait Instance {
type Interrupt: Interrupt;
fn inner() -> TimerInner;
}
}
pub trait Instance: sealed::Instance + Sized + RccPeripheral + 'static {}
macro_rules! impl_timer {
($inst:ident) => {
impl sealed::Instance for peripherals::$inst {
type Interrupt = crate::interrupt::$inst;
fn inner() -> crate::clock::TimerInner {
const INNER: TimerInner = TimerInner(crate::pac::$inst);
INNER
}
}
impl Instance for peripherals::$inst {}
};
}
crate::pac::peripherals!(
(timer, TIM2) => { impl_timer!(TIM2); };
(timer, TIM3) => { impl_timer!(TIM3); };
(timer, TIM4) => { impl_timer!(TIM4); };
(timer, TIM5) => { impl_timer!(TIM5); };
);

6
embassy-stm32/src/lib.rs
View File

@ -20,13 +20,12 @@ pub mod time;
pub mod dma;
pub mod gpio;
pub mod rcc;
mod time_driver;
// Sometimes-present hardware
#[cfg(adc)]
pub mod adc;
#[cfg(timer)]
pub mod clock;
#[cfg(dac)]
pub mod dac;
#[cfg(dbgmcu)]
@ -87,6 +86,9 @@ pub fn init(config: Config) -> Peripherals {
exti::init();
rcc::init(config.rcc);
// must be after rcc init
time_driver::init();
}
p

319
embassy-stm32/src/time_driver.rs Normal file
View File

@ -0,0 +1,319 @@
use atomic_polyfill::{AtomicU32, AtomicU8};
use core::cell::Cell;
use core::convert::TryInto;
use core::sync::atomic::{compiler_fence, Ordering};
use core::{mem, ptr};
use embassy::interrupt::InterruptExt;
use embassy::time::driver::{AlarmHandle, Driver};
use embassy::time::TICKS_PER_SECOND;
use stm32_metapac::timer::regs;
use crate::interrupt;
use crate::interrupt::{CriticalSection, Interrupt, Mutex};
use crate::pac::timer::{vals, TimGp16};
use crate::peripherals;
use crate::rcc::sealed::RccPeripheral;
use self::sealed::Instance as _;
const ALARM_COUNT: usize = 3;
type T = peripherals::TIM3;
// Clock timekeeping works with something we call "periods", which are time intervals
// of 2^15 ticks. The Clock counter value is 16 bits, so one "overflow cycle" is 2 periods.
//
// A `period` count is maintained in parallel to the Timer hardware `counter`, like this:
// - `period` and `counter` start at 0
// - `period` is incremented on overflow (at counter value 0)
// - `period` is incremented "midway" between overflows (at counter value 0x8000)
//
// Therefore, when `period` is even, counter is in 0..0x7FFF. When odd, counter is in 0x8000..0xFFFF
// This allows for now() to return the correct value even if it races an overflow.
//
// To get `now()`, `period` is read first, then `counter` is read. If the counter value matches
// the expected range for the `period` parity, we're done. If it doesn't, this means that
// a new period start has raced us between reading `period` and `counter`, so we assume the `counter` value
// corresponds to the next period.
//
// `period` is a 32bit integer, so It overflows on 2^32 * 2^15 / 32768 seconds of uptime, which is 136 years.
fn calc_now(period: u32, counter: u16) -> u64 {
((period as u64) << 15) + ((counter as u32 ^ ((period & 1) << 15)) as u64)
}
struct AlarmState {
timestamp: Cell<u64>,
// This is really a Option<(fn(*mut ()), *mut ())>
// but fn pointers aren't allowed in const yet
callback: Cell<*const ()>,
ctx: Cell<*mut ()>,
}
unsafe impl Send for AlarmState {}
impl AlarmState {
const fn new() -> Self {
Self {
timestamp: Cell::new(u64::MAX),
callback: Cell::new(ptr::null()),
ctx: Cell::new(ptr::null_mut()),
}
}
}
struct State {
/// Number of 2^15 periods elapsed since boot.
period: AtomicU32,
alarm_count: AtomicU8,
/// Timestamp at which to fire alarm. u64::MAX if no alarm is scheduled.
alarms: Mutex<[AlarmState; ALARM_COUNT]>,
}
const ALARM_STATE_NEW: AlarmState = AlarmState::new();
static STATE: State = State {
period: AtomicU32::new(0),
alarm_count: AtomicU8::new(0),
alarms: Mutex::new([ALARM_STATE_NEW; ALARM_COUNT]),
};
impl State {
fn init(&'static self) {
let r = T::regs();
T::enable();
T::reset();
let timer_freq = T::frequency();
// NOTE(unsafe) Critical section to use the unsafe methods
critical_section::with(|_| unsafe {
r.cr1().modify(|w| w.set_cen(false));
r.cnt().write(|w| w.set_cnt(0));
let psc = timer_freq.0 / TICKS_PER_SECOND as u32 - 1;
let psc: u16 = psc.try_into().unwrap();
r.psc().write(|w| w.set_psc(psc));
r.arr().write(|w| w.set_arr(u16::MAX));
// Set URS, generate update and clear URS
r.cr1().modify(|w| w.set_urs(vals::Urs::COUNTERONLY));
r.egr().write(|w| w.set_ug(true));
r.cr1().modify(|w| w.set_urs(vals::Urs::ANYEVENT));
// Mid-way point
r.ccr(0).write(|w| w.set_ccr(0x8000));
// Enable CC0, disable others
r.dier().write(|w| w.set_ccie(0, true));
let irq: <T as sealed::Instance>::Interrupt = core::mem::transmute(());
irq.unpend();
irq.enable();
r.cr1().modify(|w| w.set_cen(true));
})
}
fn on_interrupt(&self) {
let r = T::regs();
// NOTE(unsafe) Use critical section to access the methods
// XXX: reduce the size of this critical section ?
critical_section::with(|cs| unsafe {
let sr = r.sr().read();
let dier = r.dier().read();
// Clear all interrupt flags. Bits in SR are "write 0 to clear", so write the bitwise NOT.
// Other approaches such as writing all zeros, or RMWing won't work, they can
// miss interrupts.
r.sr().write_value(regs::SrGp(!sr.0));
if sr.uif() {
self.next_period();
}
// Half overflow
if sr.ccif(0) {
self.next_period();
}
for n in 0..ALARM_COUNT {
if sr.ccif(n + 1) && dier.ccie(n + 1) {
self.trigger_alarm(n, cs);
}
}
})
}
fn next_period(&self) {
let r = T::regs();
let period = self.period.fetch_add(1, Ordering::Relaxed) + 1;
let t = (period as u64) << 15;
critical_section::with(move |cs| unsafe {
r.dier().modify(move |w| {
for n in 0..ALARM_COUNT {
let alarm = &self.alarms.borrow(cs)[n];
let at = alarm.timestamp.get();
if at < t + 0xc000 {
// just enable it. `set_alarm` has already set the correct CCR val.
w.set_ccie(n + 1, true);
}
}
})
})
}
fn now(&self) -> u64 {
let r = T::regs();
let period = self.period.load(Ordering::Relaxed);
compiler_fence(Ordering::Acquire);
// NOTE(unsafe) Atomic read with no side-effects
let counter = unsafe { r.cnt().read().cnt() };
calc_now(period, counter)
}
fn get_alarm<'a>(&'a self, cs: CriticalSection<'a>, alarm: AlarmHandle) -> &'a AlarmState {
// safety: we're allowed to assume the AlarmState is created by us, and
// we never create one that's out of bounds.
unsafe { self.alarms.borrow(cs).get_unchecked(alarm.id() as usize) }
}
fn trigger_alarm(&self, n: usize, cs: CriticalSection) {
let alarm = &self.alarms.borrow(cs)[n];
alarm.timestamp.set(u64::MAX);
// Call after clearing alarm, so the callback can set another alarm.
// safety:
// - we can ignore the possiblity of `f` being unset (null) because of the safety contract of `allocate_alarm`.
// - other than that we only store valid function pointers into alarm.callback
let f: fn(*mut ()) = unsafe { mem::transmute(alarm.callback.get()) };
f(alarm.ctx.get());
}
fn allocate_alarm(&self) -> Option<AlarmHandle> {
let id = self
.alarm_count
.fetch_update(Ordering::AcqRel, Ordering::Acquire, |x| {
if x < ALARM_COUNT as u8 {
Some(x + 1)
} else {
None
}
});
match id {
Ok(id) => Some(unsafe { AlarmHandle::new(id) }),
Err(_) => None,
}
}
fn set_alarm_callback(&self, alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
critical_section::with(|cs| {
let alarm = self.get_alarm(cs, alarm);
// safety: it's OK to transmute a fn pointer into a raw pointer
let callback_ptr: *const () = unsafe { mem::transmute(callback) };
alarm.callback.set(callback_ptr);
alarm.ctx.set(ctx);
})
}
fn set_alarm(&self, alarm: AlarmHandle, timestamp: u64) {
critical_section::with(|cs| {
let r = T::regs();
let n = alarm.id() as _;
let alarm = self.get_alarm(cs, alarm);
alarm.timestamp.set(timestamp);
let t = self.now();
if timestamp <= t {
unsafe { r.dier().modify(|w| w.set_ccie(n + 1, false)) };
self.trigger_alarm(n, cs);
return;
}
let safe_timestamp = timestamp.max(t + 3);
// Write the CCR value regardless of whether we're going to enable it now or not.
// This way, when we enable it later, the right value is already set.
unsafe { r.ccr(n + 1).write(|w| w.set_ccr(safe_timestamp as u16)) };
// Enable it if it'll happen soon. Otherwise, `next_period` will enable it.
let diff = timestamp - t;
// NOTE(unsafe) We're in a critical section
unsafe { r.dier().modify(|w| w.set_ccie(n + 1, diff < 0xc000)) };
})
}
}
struct RtcDriver;
embassy::time_driver_impl!(RtcDriver);
impl Driver for RtcDriver {
fn now() -> u64 {
STATE.now()
}
unsafe fn allocate_alarm() -> Option<AlarmHandle> {
STATE.allocate_alarm()
}
fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
STATE.set_alarm_callback(alarm, callback, ctx)
}
fn set_alarm(alarm: AlarmHandle, timestamp: u64) {
STATE.set_alarm(alarm, timestamp)
}
}
#[interrupt]
fn TIM3() {
STATE.on_interrupt()
}
pub(crate) fn init() {
STATE.init()
}
// ------------------------------------------------------
pub(crate) mod sealed {
use super::*;
pub trait Instance {
type Interrupt: Interrupt;
fn regs() -> TimGp16;
}
}
pub trait Instance: sealed::Instance + Sized + RccPeripheral + 'static {}
macro_rules! impl_timer {
($inst:ident) => {
impl sealed::Instance for peripherals::$inst {
type Interrupt = crate::interrupt::$inst;
fn regs() -> TimGp16 {
crate::pac::$inst
}
}
impl Instance for peripherals::$inst {}
};
}
crate::pac::peripherals!(
(timer, TIM2) => { impl_timer!(TIM2); };
(timer, TIM3) => { impl_timer!(TIM3); };
(timer, TIM4) => { impl_timer!(TIM4); };
(timer, TIM5) => { impl_timer!(TIM5); };
);

12
embassy/src/executor/mod.rs
View File

@ -109,18 +109,13 @@ pub struct Executor {
}
impl Executor {
pub const fn new() -> Self {
pub fn new() -> Self {
Self {
inner: raw::Executor::new(|_| cortex_m::asm::sev(), ptr::null_mut()),
not_send: PhantomData,
}
}
#[cfg(feature = "time")]
pub fn set_alarm(&mut self, alarm: &'static dyn crate::time::Alarm) {
self.inner.set_alarm(alarm);
}
/// Runs the executor.
///
/// This function never returns.
@ -161,11 +156,6 @@ impl<I: Interrupt> InterruptExecutor<I> {
}
}
#[cfg(feature = "time")]
pub fn set_alarm(&mut self, alarm: &'static dyn crate::time::Alarm) {
self.inner.set_alarm(alarm);
}
/// Start the executor.
///
/// `init` is called in the interrupt context, then the interrupt is

37
embassy/src/executor/raw.rs
View File

@ -15,7 +15,9 @@ use super::SpawnToken;
#[cfg(feature = "time")]
use super::timer_queue::{TimerQueue, TimerQueueItem};
#[cfg(feature = "time")]
use crate::time::{Alarm, Instant};
use crate::time::driver::{self, AlarmHandle};
#[cfg(feature = "time")]
use crate::time::Instant;
/// Task is spawned (has a future)
pub(crate) const STATE_SPAWNED: u32 = 1 << 0;
@ -169,11 +171,16 @@ pub struct Executor {
#[cfg(feature = "time")]
timer_queue: TimerQueue,
#[cfg(feature = "time")]
alarm: Option<&'static dyn Alarm>,
alarm: AlarmHandle,
}
impl Executor {
pub const fn new(signal_fn: fn(*mut ()), signal_ctx: *mut ()) -> Self {
pub fn new(signal_fn: fn(*mut ()), signal_ctx: *mut ()) -> Self {
#[cfg(feature = "time")]
let alarm = unsafe { unwrap!(driver::allocate_alarm()) };
#[cfg(feature = "time")]
driver::set_alarm_callback(alarm, signal_fn, signal_ctx);
Self {
run_queue: RunQueue::new(),
signal_fn,
@ -182,15 +189,10 @@ impl Executor {
#[cfg(feature = "time")]
timer_queue: TimerQueue::new(),
#[cfg(feature = "time")]
alarm: None,
alarm,
}
}
#[cfg(feature = "time")]
pub fn set_alarm(&mut self, alarm: &'static dyn Alarm) {
self.alarm = Some(alarm);
}
pub fn set_signal_ctx(&mut self, signal_ctx: *mut ()) {
self.signal_ctx = signal_ctx;
}
@ -209,11 +211,9 @@ impl Executor {
pub unsafe fn run_queued(&'static self) {
#[cfg(feature = "time")]
if self.alarm.is_some() {
self.timer_queue.dequeue_expired(Instant::now(), |p| {
p.as_ref().enqueue();
});
}
self.timer_queue.dequeue_expired(Instant::now(), |p| {
p.as_ref().enqueue();
});
self.run_queue.dequeue_all(|p| {
let task = p.as_ref();
@ -239,13 +239,12 @@ impl Executor {
self.timer_queue.update(p);
});
// If this is in the past, set_alarm will immediately trigger the alarm,
// which will make the wfe immediately return so we do another loop iteration.
#[cfg(feature = "time")]
if let Some(alarm) = self.alarm {
{
// If this is in the past, set_alarm will immediately trigger the alarm,
// which will make the wfe immediately return so we do another loop iteration.
let next_expiration = self.timer_queue.next_expiration();
alarm.set_callback(self.signal_fn, self.signal_ctx);
alarm.set(next_expiration.as_ticks());
driver::set_alarm(self.alarm, next_expiration.as_ticks());
}
}

118
embassy/src/time/driver.rs Normal file
View File

@ -0,0 +1,118 @@
/// Alarm handle, assigned by the driver.
#[derive(Clone, Copy)]
pub struct AlarmHandle {
id: u8,
}
impl AlarmHandle {
/// Create an AlarmHandle
///
/// Safety: May only be called by the current global Driver impl.
/// The impl is allowed to rely on the fact that all `AlarmHandle` instances
/// are created by itself in unsafe code (e.g. indexing operations)
pub unsafe fn new(id: u8) -> Self {
Self { id }
}
/// Get the ID of the AlarmHandle.
pub fn id(&self) -> u8 {
self.id
}
}
/// Time driver
pub trait Driver {
/// Return the current timestamp in ticks.
/// This is guaranteed to be monotonic, i.e. a call to now() will always return
/// a greater or equal value than earler calls.
fn now() -> u64;
/// Try allocating an alarm handle. Returns None if no alarms left.
/// Initially the alarm has no callback set, and a null `ctx` pointer.
///
/// # Safety
/// It is UB to make the alarm fire before setting a callback.
unsafe fn allocate_alarm() -> Option<AlarmHandle>;
/// Sets the callback function to be called when the alarm triggers.
/// The callback may be called from any context (interrupt or thread mode).
fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ());
/// Sets an alarm at the given timestamp. When the current timestamp reaches that
/// timestamp, the provided callback funcion will be called.
///
/// When callback is called, it is guaranteed that now() will return a value greater or equal than timestamp.
///
/// Only one alarm can be active at a time. This overwrites any previously-set alarm if any.
fn set_alarm(alarm: AlarmHandle, timestamp: u64);
}
extern "Rust" {
fn _embassy_time_now() -> u64;
fn _embassy_time_allocate_alarm() -> Option<AlarmHandle>;
fn _embassy_time_set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ());
fn _embassy_time_set_alarm(alarm: AlarmHandle, timestamp: u64);
}
pub(crate) fn now() -> u64 {
unsafe { _embassy_time_now() }
}
/// Safety: it is UB to make the alarm fire before setting a callback.
pub(crate) unsafe fn allocate_alarm() -> Option<AlarmHandle> {
_embassy_time_allocate_alarm()
}
pub(crate) fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
unsafe { _embassy_time_set_alarm_callback(alarm, callback, ctx) }
}
pub(crate) fn set_alarm(alarm: AlarmHandle, timestamp: u64) {
unsafe { _embassy_time_set_alarm(alarm, timestamp) }
}
/// Set the time Driver implementation.
///
/// # Example
///
/// ```
/// struct MyDriver;
/// embassy::time_driver_impl!(MyDriver);
///
/// unsafe impl embassy::time::driver::Driver for MyDriver {
/// fn now() -> u64 {
/// todo!()
/// }
/// unsafe fn allocate_alarm() -> Option<AlarmHandle> {
/// todo!()
/// }
/// fn set_alarm_callback(alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
/// todo!()
/// }
/// fn set_alarm(alarm: AlarmHandle, timestamp: u64) {
/// todo!()
/// }
/// }
///
#[macro_export]
macro_rules! time_driver_impl {
($t: ty) => {
#[no_mangle]
fn _embassy_time_now() -> u64 {
<$t as $crate::time::driver::Driver>::now()
}
#[no_mangle]
unsafe fn _embassy_time_allocate_alarm() -> Option<AlarmHandle> {
<$t as $crate::time::driver::Driver>::allocate_alarm()
}
#[no_mangle]
fn _embassy_time_set_alarm_callback(
alarm: AlarmHandle,
callback: fn(*mut ()),
ctx: *mut (),
) {
<$t as $crate::time::driver::Driver>::set_alarm_callback(alarm, callback, ctx)
}
#[no_mangle]
fn _embassy_time_set_alarm(alarm: AlarmHandle, timestamp: u64) {
<$t as $crate::time::driver::Driver>::set_alarm(alarm, timestamp)
}
};
}

7
embassy/src/time/instant.rs
View File

@ -1,8 +1,7 @@
use core::fmt;
use core::ops::{Add, AddAssign, Sub, SubAssign};
use super::TICKS_PER_SECOND;
use super::{now, Duration};
use super::{driver, Duration, TICKS_PER_SECOND};
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
#[cfg_attr(feature = "defmt", derive(defmt::Format))]
@ -17,7 +16,9 @@ impl Instant {
/// Returns an Instant representing the current time.
pub fn now() -> Instant {
Instant { ticks: now() }
Instant {
ticks: driver::now(),
}
}
/// Instant as clock ticks since MCU start.

22
embassy/src/time/mod.rs
View File

@ -1,17 +1,15 @@
//! Time abstractions
//! To use these abstractions, first call `set_clock` with an instance of an [Clock](trait.Clock.html).
//!
mod delay;
pub mod driver;
mod duration;
mod instant;
mod timer;
mod traits;
pub use delay::{block_for, Delay};
pub use duration::Duration;
pub use instant::Instant;
pub use timer::{with_timeout, Ticker, TimeoutError, Timer};
pub use traits::*;
#[cfg(feature = "time-tick-1000hz")]
pub const TICKS_PER_SECOND: u64 = 1_000;
@ -21,19 +19,3 @@ pub const TICKS_PER_SECOND: u64 = 32_768;
#[cfg(feature = "time-tick-1mhz")]
pub const TICKS_PER_SECOND: u64 = 1_000_000;
static mut CLOCK: Option<&'static dyn Clock> = None;
/// Sets the clock used for the timing abstractions
///
/// Safety: Sets a mutable global.
pub unsafe fn set_clock(clock: &'static dyn Clock) {
CLOCK = Some(clock);
}
/// Return the current timestamp in ticks.
/// This is guaranteed to be monotonic, i.e. a call to now() will always return
/// a greater or equal value than earler calls.
pub(crate) fn now() -> u64 {
unsafe { unwrap!(CLOCK, "No clock set").now() }
}

32
embassy/src/time/traits.rs
View File

@ -1,32 +0,0 @@
/// Monotonic clock
pub trait Clock {
/// Return the current timestamp in ticks.
/// This is guaranteed to be monotonic, i.e. a call to now() will always return
/// a greater or equal value than earler calls.
fn now(&self) -> u64;
}
impl<T: Clock + ?Sized> Clock for &T {
fn now(&self) -> u64 {
T::now(self)
}
}
/// Trait to register a callback at a given timestamp.
pub trait Alarm {
/// Sets the callback function to be called when the alarm triggers.
/// The callback may be called from any context (interrupt or thread mode).
fn set_callback(&self, callback: fn(*mut ()), ctx: *mut ());
/// Sets an alarm at the given timestamp. When the clock reaches that
/// timestamp, the provided callback funcion will be called.
///
/// When callback is called, it is guaranteed that now() will return a value greater or equal than timestamp.
///
/// Only one alarm can be active at a time. This overwrites any previously-set alarm if any.
fn set(&self, timestamp: u64);
/// Clears the previously-set alarm.
/// If no alarm was set, this is a noop.
fn clear(&self);
}

1
examples/nrf/src/bin/blinky.rs
View File

@ -6,7 +6,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_nrf::gpio::{Level, Output, OutputDrive};

3
examples/nrf/src/bin/executor_fairness_test.rs
View File

@ -8,10 +8,9 @@ mod example_common;
use example_common::*;
use core::task::Poll;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Instant, Timer};
use embassy_nrf::{interrupt, Peripherals};
use embassy_nrf::Peripherals;
#[embassy::task]
async fn run1() {

3
examples/nrf/src/bin/gpiote_channel.rs
View File

@ -7,11 +7,10 @@
mod example_common;
use example_common::*;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_nrf::gpio::{Input, Pull};
use embassy_nrf::gpiote::{InputChannel, InputChannelPolarity};
use embassy_nrf::{interrupt, Peripherals};
use embassy_nrf::Peripherals;
#[embassy::main]
async fn main(_spawner: Spawner, p: Peripherals) {

2
examples/nrf/src/bin/gpiote_port.rs
View File

@ -6,12 +6,10 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::traits::gpio::{WaitForHigh, WaitForLow};
use embassy_nrf::gpio::{AnyPin, Input, Pin as _, Pull};
use embassy_nrf::gpiote::PortInput;
use embassy_nrf::interrupt;
use embassy_nrf::Peripherals;
use example_common::*;

1
examples/nrf/src/bin/mpsc.rs
View File

@ -6,7 +6,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy::util::mpsc::TryRecvError;

18
examples/nrf/src/bin/multiprio.rs
View File

@ -68,7 +68,7 @@ use embassy::executor::{Executor, InterruptExecutor};
use embassy::interrupt::InterruptExt;
use embassy::time::{Duration, Instant, Timer};
use embassy::util::Forever;
use embassy_nrf::{interrupt, peripherals, rtc};
use embassy_nrf::interrupt;
#[embassy::task]
async fn run_high() {
@ -112,30 +112,20 @@ async fn run_low() {
}
}
static RTC: Forever<rtc::RTC<peripherals::RTC1>> = Forever::new();
static ALARM_HIGH: Forever<rtc::Alarm<peripherals::RTC1>> = Forever::new();
static EXECUTOR_HIGH: Forever<InterruptExecutor<interrupt::SWI1_EGU1>> = Forever::new();
static ALARM_MED: Forever<rtc::Alarm<peripherals::RTC1>> = Forever::new();
static EXECUTOR_MED: Forever<InterruptExecutor<interrupt::SWI0_EGU0>> = Forever::new();
static ALARM_LOW: Forever<rtc::Alarm<peripherals::RTC1>> = Forever::new();
static EXECUTOR_LOW: Forever<Executor> = Forever::new();
#[entry]
fn main() -> ! {
info!("Hello World!");
let p = embassy_nrf::init(Default::default());
let rtc = RTC.put(rtc::RTC::new(p.RTC1, interrupt::take!(RTC1)));
rtc.start();
unsafe { embassy::time::set_clock(rtc) };
let _p = embassy_nrf::init(Default::default());
// High-priority executor: SWI1_EGU1, priority level 6
let irq = interrupt::take!(SWI1_EGU1);
irq.set_priority(interrupt::Priority::P6);
let alarm = ALARM_HIGH.put(rtc.alarm2());
let executor = EXECUTOR_HIGH.put(InterruptExecutor::new(irq));
executor.set_alarm(alarm);
executor.start(|spawner| {
unwrap!(spawner.spawn(run_high()));
});
@ -143,17 +133,13 @@ fn main() -> ! {
// Medium-priority executor: SWI0_EGU0, priority level 7
let irq = interrupt::take!(SWI0_EGU0);
irq.set_priority(interrupt::Priority::P7);
let alarm = ALARM_MED.put(rtc.alarm1());
let executor = EXECUTOR_MED.put(InterruptExecutor::new(irq));
executor.set_alarm(alarm);
executor.start(|spawner| {
unwrap!(spawner.spawn(run_med()));
});
// Low priority executor: runs in thread mode, using WFE/SEV
let alarm = ALARM_LOW.put(rtc.alarm0());
let executor = EXECUTOR_LOW.put(Executor::new());
executor.set_alarm(alarm);
executor.run(|spawner| {
unwrap!(spawner.spawn(run_low()));
});

3
examples/nrf/src/bin/ppi.rs
View File

@ -8,12 +8,11 @@ mod example_common;
use example_common::*;
use core::future::pending;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_nrf::gpio::{Input, Level, Output, OutputDrive, Pull};
use embassy_nrf::gpiote::{self, InputChannel, InputChannelPolarity};
use embassy_nrf::ppi::Ppi;
use embassy_nrf::{interrupt, Peripherals};
use embassy_nrf::Peripherals;
use gpiote::{OutputChannel, OutputChannelPolarity};
#[embassy::main]

4
examples/nrf/src/bin/pwm.rs
View File

@ -5,11 +5,11 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::{panic, *};
use defmt::*;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_nrf::pwm::{Prescaler, Pwm};
use embassy_nrf::{interrupt, Peripherals};
use embassy_nrf::Peripherals;
// for i in range(1024): print(int((math.sin(i/512*math.pi)*0.4+0.5)**2*32767), ', ', end='')
static DUTY: [u16; 1024] = [

15
examples/nrf/src/bin/raw_spawn.rs
View File

@ -7,13 +7,11 @@ use example_common::*;
use core::mem;
use cortex_m_rt::entry;
use defmt::panic;
use embassy::executor::raw::Task;
use embassy::executor::Executor;
use embassy::time::{Duration, Timer};
use embassy::util::Forever;
use embassy_nrf::peripherals;
use embassy_nrf::{interrupt, rtc};
async fn run1() {
loop {
@ -29,23 +27,14 @@ async fn run2() {
}
}
static RTC: Forever<rtc::RTC<peripherals::RTC1>> = Forever::new();
static ALARM: Forever<rtc::Alarm<peripherals::RTC1>> = Forever::new();
static EXECUTOR: Forever<Executor> = Forever::new();
#[entry]
fn main() -> ! {
info!("Hello World!");
let p = embassy_nrf::init(Default::default());
let rtc = RTC.put(rtc::RTC::new(p.RTC1, interrupt::take!(RTC1)));
rtc.start();
unsafe { embassy::time::set_clock(rtc) };
let alarm = ALARM.put(rtc.alarm0());
let _p = embassy_nrf::init(Default::default());
let executor = EXECUTOR.put(Executor::new());
executor.set_alarm(alarm);
let run1_task = Task::new();
let run2_task = Task::new();

1
examples/nrf/src/bin/timer.rs
View File

@ -8,7 +8,6 @@ mod example_common;
use embassy_nrf::Peripherals;
use example_common::*;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};

1
examples/stm32f4/src/bin/blinky.rs
View File

@ -6,7 +6,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_stm32::dbgmcu::Dbgmcu;

1
examples/stm32f4/src/bin/button_exti.rs
View File

@ -6,7 +6,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::exti::ExtiInput;

2
examples/stm32f4/src/bin/hello.rs
View File

@ -4,7 +4,7 @@
#![feature(type_alias_impl_trait)]
#![allow(incomplete_features)]
use defmt::{info, panic};
use defmt::info;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_stm32::time::Hertz;

1
examples/stm32f4/src/bin/spi_dma.rs
View File

@ -8,7 +8,6 @@
mod example_common;
use core::fmt::Write;
use core::str::from_utf8;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::spi::{Config, Spi};

1
examples/stm32f4/src/bin/usart_dma.rs
View File

@ -7,7 +7,6 @@
#[path = "../example_common.rs"]
mod example_common;
use core::fmt::Write;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::dma::NoDma;

17
examples/stm32h7/src/bin/blinky.rs
View File

@ -6,30 +6,29 @@
#[path = "../example_common.rs"]
mod example_common;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::gpio::{Level, Output, Speed};
use embassy_stm32::Peripherals;
use embedded_hal::digital::v2::OutputPin;
use example_common::*;
use cortex_m_rt::entry;
use embassy_stm32::dbgmcu::Dbgmcu;
#[entry]
fn main() -> ! {
#[embassy::main]
async fn main(_spawner: Spawner, p: Peripherals) {
info!("Hello World!");
unsafe { Dbgmcu::enable_all() };
let p = embassy_stm32::init(Default::default());
let mut led = Output::new(p.PB14, Level::High, Speed::Low);
loop {
info!("high");
led.set_high().unwrap();
cortex_m::asm::delay(10_000_000);
Timer::after(Duration::from_millis(500)).await;
info!("low");
led.set_low().unwrap();
cortex_m::asm::delay(10_000_000);
Timer::after(Duration::from_millis(500)).await;
}
}

13
examples/stm32h7/src/bin/eth.rs
View File

@ -19,7 +19,6 @@ use embassy_macros::interrupt_take;
use embassy_net::{
Config as NetConfig, Ipv4Address, Ipv4Cidr, StackResources, StaticConfigurator, TcpSocket,
};
use embassy_stm32::clock::{Alarm, Clock};
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::eth::lan8742a::LAN8742A;
use embassy_stm32::eth::{Ethernet, State};
@ -27,7 +26,7 @@ use embassy_stm32::rng::Random;
use embassy_stm32::{interrupt, peripherals};
use heapless::Vec;
use panic_probe as _;
use peripherals::{RNG, TIM2};
use peripherals::RNG;
#[embassy::task]
async fn main_task(
@ -86,8 +85,6 @@ fn _embassy_rand(buf: &mut [u8]) {
static mut RNG_INST: Option<Random<RNG>> = None;
static EXECUTOR: Forever<Executor> = Forever::new();
static TIMER_RTC: Forever<Clock<TIM2>> = Forever::new();
static ALARM: Forever<Alarm<TIM2>> = Forever::new();
static STATE: Forever<State<'static, 4, 4>> = Forever::new();
static ETH: Forever<Ethernet<'static, LAN8742A, 4, 4>> = Forever::new();
static CONFIG: Forever<StaticConfigurator> = Forever::new();
@ -105,13 +102,6 @@ fn main() -> ! {
let p = embassy_stm32::init(config());
let rtc_int = interrupt_take!(TIM2);
let rtc = TIMER_RTC.put(Clock::new(p.TIM2, rtc_int));
rtc.start();
let alarm = ALARM.put(rtc.alarm1());
unsafe { embassy::time::set_clock(rtc) };
let rng = Random::new(p.RNG);
unsafe {
RNG_INST.replace(rng);
@ -136,7 +126,6 @@ fn main() -> ! {
let config = CONFIG.put(config);
let executor = EXECUTOR.put(Executor::new());
executor.set_alarm(alarm);
executor.run(move |spawner| {
unwrap!(spawner.spawn(main_task(eth, config, spawner)));

10
examples/stm32h7/src/bin/spi.rs
View File

@ -9,7 +9,6 @@ mod example_common;
use core::fmt::Write;
use embassy::executor::Executor;
use embassy::time::Clock;
use embassy::util::Forever;
use embassy_stm32::dma::NoDma;
use embassy_stm32::spi;
@ -38,14 +37,6 @@ async fn main_task(mut spi: spi::Spi<'static, SPI3, NoDma, NoDma>) {
}
}
struct ZeroClock;
impl Clock for ZeroClock {
fn now(&self) -> u64 {
0
}
}
static EXECUTOR: Forever<Executor> = Forever::new();
#[entry]
@ -69,7 +60,6 @@ fn main() -> ! {
spi::Config::default(),
);
unsafe { embassy::time::set_clock(&ZeroClock) };
let executor = EXECUTOR.put(Executor::new());
executor.run(|spawner| {

10
examples/stm32h7/src/bin/spi_dma.rs
View File

@ -9,7 +9,6 @@ mod example_common;
use core::fmt::Write;
use embassy::executor::Executor;
use embassy::time::Clock;
use embassy::util::Forever;
use embassy_stm32::time::U32Ext;
use embassy_traits::spi::FullDuplex;
@ -34,14 +33,6 @@ async fn main_task(mut spi: spi::Spi<'static, SPI3, DMA1_CH3, DMA1_CH4>) {
}
}
struct ZeroClock;
impl Clock for ZeroClock {
fn now(&self) -> u64 {
0
}
}
static EXECUTOR: Forever<Executor> = Forever::new();
#[entry]
@ -65,7 +56,6 @@ fn main() -> ! {
spi::Config::default(),
);
unsafe { embassy::time::set_clock(&ZeroClock) };
let executor = EXECUTOR.put(Executor::new());
executor.run(|spawner| {

11
examples/stm32h7/src/bin/usart.rs
View File

@ -8,7 +8,6 @@
mod example_common;
use cortex_m::prelude::_embedded_hal_blocking_serial_Write;
use embassy::executor::Executor;
use embassy::time::Clock;
use embassy::util::Forever;
use embassy_stm32::dma::NoDma;
use embassy_stm32::usart::{Config, Uart};
@ -34,14 +33,6 @@ async fn main_task() {
}
}
struct ZeroClock;
impl Clock for ZeroClock {
fn now(&self) -> u64 {
0
}
}
static EXECUTOR: Forever<Executor> = Forever::new();
#[entry]
@ -52,8 +43,6 @@ fn main() -> ! {
Dbgmcu::enable_all();
}
unsafe { embassy::time::set_clock(&ZeroClock) };
let executor = EXECUTOR.put(Executor::new());
executor.run(|spawner| {

11
examples/stm32h7/src/bin/usart_dma.rs
View File

@ -8,7 +8,6 @@
mod example_common;
use core::fmt::Write;
use embassy::executor::Executor;
use embassy::time::Clock;
use embassy::util::Forever;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::dma::NoDma;
@ -36,14 +35,6 @@ async fn main_task() {
}
}
struct ZeroClock;
impl Clock for ZeroClock {
fn now(&self) -> u64 {
0
}
}
static EXECUTOR: Forever<Executor> = Forever::new();
#[entry]
@ -54,8 +45,6 @@ fn main() -> ! {
Dbgmcu::enable_all();
}
unsafe { embassy::time::set_clock(&ZeroClock) };
let executor = EXECUTOR.put(Executor::new());
executor.run(|spawner| {

1
examples/stm32l0/src/bin/blinky.rs
View File

@ -7,7 +7,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_stm32::gpio::{Level, Output, Speed};

1
examples/stm32l0/src/bin/button_exti.rs
View File

@ -7,7 +7,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::exti::ExtiInput;
use embassy_stm32::gpio::{Input, Pull};

1
examples/stm32l0/src/bin/usart_dma.rs
View File

@ -9,7 +9,6 @@ mod example_common;
use example_common::*;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::usart::{Config, Uart};
use embassy_stm32::{rcc, Peripherals};

1
examples/stm32l4/src/bin/blinky.rs
View File

@ -6,7 +6,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy::time::{Duration, Timer};
use embassy_stm32::dbgmcu::Dbgmcu;

1
examples/stm32l4/src/bin/button_exti.rs
View File

@ -6,7 +6,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::exti::ExtiInput;

1
examples/stm32l4/src/bin/spi_dma.rs
View File

@ -7,7 +7,6 @@
#[path = "../example_common.rs"]
mod example_common;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::gpio::{Input, Level, Output, Pull, Speed};

1
examples/stm32l4/src/bin/usart_dma.rs
View File

@ -7,7 +7,6 @@
#[path = "../example_common.rs"]
mod example_common;
use core::fmt::Write;
use defmt::panic;
use embassy::executor::Spawner;
use embassy_stm32::dbgmcu::Dbgmcu;
use embassy_stm32::dma::NoDma;