Merge pull request #4716 from liebman/stm32wl-low-power

support low-power executor on stm32wlex

19 files changed, 705 insertions, 22 deletions

diff --git a/embassy-stm32/CHANGELOG.md b/embassy-stm32/CHANGELOG.md
index a9ab78e31..71989eb3d 100644
--- a/embassy-stm32/CHANGELOG.md
+++ b/embassy-stm32/CHANGELOG.md
@@ -38,6 +38,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - fix: usart: fix race condition in ringbuffered usart
 - feat: stm32/fdcan: add ability to control automatic recovery from bus off ([#4821](https://github.com/embassy-rs/embassy/pull/4821))
 - low-power: update rtc api to allow reconfig
+- feat: Added RTC low-power support for STM32WLEx ([#4716](https://github.com/embassy-rs/embassy/pull/4716))
 
 ## 0.4.0 - 2025-08-26
 
diff --git a/embassy-stm32/src/adc/mod.rs b/embassy-stm32/src/adc/mod.rs
index 22ed8295f..ea7341f75 100644
--- a/embassy-stm32/src/adc/mod.rs
+++ b/embassy-stm32/src/adc/mod.rs
@@ -87,14 +87,18 @@ pub(crate) trait SealedAdcChannel<T> {
 /// Performs a busy-wait delay for a specified number of microseconds.
 #[allow(unused)]
 pub(crate) fn blocking_delay_us(us: u32) {
-    #[cfg(feature = "time")]
-    embassy_time::block_for(embassy_time::Duration::from_micros(us as u64));
-    #[cfg(not(feature = "time"))]
-    {
-        let freq = unsafe { crate::rcc::get_freqs() }.sys.to_hertz().unwrap().0 as u64;
-        let us = us as u64;
-        let cycles = freq * us / 1_000_000;
-        cortex_m::asm::delay(cycles as u32);
+    cfg_if::cfg_if! {
+        // this does strange things on stm32wlx in low power mode depending on exactly when it's called
+        // as in sometimes 15 us (1 tick) would take > 20 seconds.
+        if #[cfg(all(feature = "time", all(not(feature = "low-power"), not(stm32wlex))))] {
+            let duration = embassy_time::Duration::from_micros(us as u64);
+            embassy_time::block_for(duration);
+        } else {
+            let freq = unsafe { crate::rcc::get_freqs() }.sys.to_hertz().unwrap().0 as u64;
+            let us = us as u64;
+            let cycles = freq * us / 1_000_000;
+            cortex_m::asm::delay(cycles as u32);
+        }
     }
 }
 
diff --git a/embassy-stm32/src/adc/v3.rs b/embassy-stm32/src/adc/v3.rs
index d9a3ce21d..e5b9a5d85 100644
--- a/embassy-stm32/src/adc/v3.rs
+++ b/embassy-stm32/src/adc/v3.rs
@@ -430,6 +430,9 @@ impl<'d, T: Instance> Adc<'d, T> {
             "Asynchronous read sequence cannot be more than 16 in length"
         );
 
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        let _device_busy = crate::low_power::DeviceBusy::new();
+
         // Ensure no conversions are ongoing and ADC is enabled.
         Self::cancel_conversions();
         self.enable();
diff --git a/embassy-stm32/src/i2c/v2.rs b/embassy-stm32/src/i2c/v2.rs
index 01b6b8800..6f2d03bd1 100644
--- a/embassy-stm32/src/i2c/v2.rs
+++ b/embassy-stm32/src/i2c/v2.rs
@@ -70,6 +70,11 @@ fn debug_print_interrupts(isr: stm32_metapac::i2c::regs::Isr) {
 }
 
 pub(crate) unsafe fn on_interrupt<T: Instance>() {
+    // restore the clocks to their last configured state as
+    // much is lost in STOP modes
+    #[cfg(all(feature = "low-power", stm32wlex))]
+    crate::low_power::on_wakeup_irq();
+
     let regs = T::info().regs;
     let isr = regs.isr().read();
 
@@ -814,6 +819,8 @@ impl<'d, IM: MasterMode> I2c<'d, Async, IM> {
 
     /// Write.
     pub async fn write(&mut self, address: u8, write: &[u8]) -> Result<(), Error> {
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        let _device_busy = crate::low_power::DeviceBusy::new();
         let timeout = self.timeout();
         if write.is_empty() {
             self.write_internal(address.into(), write, true, timeout)
@@ -828,6 +835,8 @@ impl<'d, IM: MasterMode> I2c<'d, Async, IM> {
     ///
     /// The buffers are concatenated in a single write transaction.
     pub async fn write_vectored(&mut self, address: Address, write: &[&[u8]]) -> Result<(), Error> {
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        let _device_busy = crate::low_power::DeviceBusy::new();
         let timeout = self.timeout();
 
         if write.is_empty() {
@@ -851,6 +860,8 @@ impl<'d, IM: MasterMode> I2c<'d, Async, IM> {
 
     /// Read.
     pub async fn read(&mut self, address: u8, buffer: &mut [u8]) -> Result<(), Error> {
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        let _device_busy = crate::low_power::DeviceBusy::new();
         let timeout = self.timeout();
 
         if buffer.is_empty() {
@@ -863,6 +874,8 @@ impl<'d, IM: MasterMode> I2c<'d, Async, IM> {
 
     /// Write, restart, read.
     pub async fn write_read(&mut self, address: u8, write: &[u8], read: &mut [u8]) -> Result<(), Error> {
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        let _device_busy = crate::low_power::DeviceBusy::new();
         let timeout = self.timeout();
 
         if write.is_empty() {
@@ -888,6 +901,8 @@ impl<'d, IM: MasterMode> I2c<'d, Async, IM> {
     ///
     /// [transaction contract]: embedded_hal_1::i2c::I2c::transaction
     pub async fn transaction(&mut self, addr: u8, operations: &mut [Operation<'_>]) -> Result<(), Error> {
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        let _device_busy = crate::low_power::DeviceBusy::new();
         let _ = addr;
         let _ = operations;
         todo!()
diff --git a/embassy-stm32/src/low_power.rs b/embassy-stm32/src/low_power.rs
index 74cd11b93..cde3153f6 100644
--- a/embassy-stm32/src/low_power.rs
+++ b/embassy-stm32/src/low_power.rs
@@ -68,6 +68,39 @@ use crate::rtc::Rtc;
 
 static mut EXECUTOR: Option<Executor> = None;
 
+#[cfg(stm32wlex)]
+pub(crate) use self::busy::DeviceBusy;
+#[cfg(stm32wlex)]
+mod busy {
+    use core::sync::atomic::{AtomicU32, Ordering};
+
+    // Count of devices blocking STOP
+    static STOP_BLOCKED: AtomicU32 = AtomicU32::new(0);
+
+    /// Check if STOP1 is blocked.
+    pub(crate) fn stop_blocked() -> bool {
+        STOP_BLOCKED.load(Ordering::SeqCst) > 0
+    }
+
+    /// When ca device goes busy it will construct one of these where it will be dropped when the device goes idle.
+    pub(crate) struct DeviceBusy {}
+
+    impl DeviceBusy {
+        /// Create a new DeviceBusy.
+        pub(crate) fn new() -> Self {
+            STOP_BLOCKED.fetch_add(1, Ordering::SeqCst);
+            trace!("low power: device busy: Stop:{}", STOP_BLOCKED.load(Ordering::SeqCst));
+            Self {}
+        }
+    }
+
+    impl Drop for DeviceBusy {
+        fn drop(&mut self) {
+            STOP_BLOCKED.fetch_sub(1, Ordering::SeqCst);
+            trace!("low power: device idle: Stop:{}", STOP_BLOCKED.load(Ordering::SeqCst));
+        }
+    }
+}
 #[cfg(not(stm32u0))]
 foreach_interrupt! {
     (RTC, rtc, $block:ident, WKUP, $irq:ident) => {
@@ -92,7 +125,10 @@ foreach_interrupt! {
 
 #[allow(dead_code)]
 pub(crate) unsafe fn on_wakeup_irq() {
-    EXECUTOR.as_mut().unwrap().on_wakeup_irq();
+    if EXECUTOR.is_some() {
+        trace!("low power: wakeup irq");
+        EXECUTOR.as_mut().unwrap().on_wakeup_irq();
+    }
 }
 
 /// Configure STOP mode with RTC.
@@ -127,10 +163,10 @@ pub enum StopMode {
     Stop2,
 }
 
-#[cfg(any(stm32l4, stm32l5, stm32u5, stm32wba, stm32u0))]
+#[cfg(any(stm32l4, stm32l5, stm32u5, stm32wba, stm32wlex, stm32u0))]
 use stm32_metapac::pwr::vals::Lpms;
 
-#[cfg(any(stm32l4, stm32l5, stm32u5, stm32wba, stm32u0))]
+#[cfg(any(stm32l4, stm32l5, stm32u5, stm32wba, stm32wlex, stm32u0))]
 impl Into<Lpms> for StopMode {
     fn into(self) -> Lpms {
         match self {
@@ -180,6 +216,22 @@ impl Executor {
     }
 
     unsafe fn on_wakeup_irq(&mut self) {
+        #[cfg(stm32wlex)]
+        {
+            let extscr = crate::pac::PWR.extscr().read();
+            if extscr.c1stop2f() || extscr.c1stopf() {
+                // when we wake from any stop mode we need to re-initialize the rcc
+                crate::rcc::apply_resume_config();
+                if extscr.c1stop2f() {
+                    // when we wake from STOP2, we need to re-initialize the time driver
+                    critical_section::with(|cs| crate::time_driver::init_timer(cs));
+                    // reset the refcounts for STOP2 and STOP1 (initializing the time driver will increment one of them for the timer)
+                    // and given that we just woke from STOP2, we can reset them
+                    crate::rcc::REFCOUNT_STOP2 = 0;
+                    crate::rcc::REFCOUNT_STOP1 = 0;
+                }
+            }
+        }
         self.time_driver.resume_time();
         trace!("low power: resume");
     }
@@ -195,10 +247,22 @@ impl Executor {
         self.time_driver.reconfigure_rtc(f);
     }
 
+    fn stop1_ok_to_enter(&self) -> bool {
+        #[cfg(stm32wlex)]
+        if self::busy::stop_blocked() {
+            return false;
+        }
+        unsafe { crate::rcc::REFCOUNT_STOP1 == 0 }
+    }
+
+    fn stop2_ok_to_enter(&self) -> bool {
+        self.stop1_ok_to_enter() && unsafe { crate::rcc::REFCOUNT_STOP2 == 0 }
+    }
+
     fn stop_mode(&self) -> Option<StopMode> {
-        if unsafe { crate::rcc::REFCOUNT_STOP2 == 0 } && unsafe { crate::rcc::REFCOUNT_STOP1 == 0 } {
+        if self.stop2_ok_to_enter() {
             Some(StopMode::Stop2)
-        } else if unsafe { crate::rcc::REFCOUNT_STOP1 == 0 } {
+        } else if self.stop1_ok_to_enter() {
             Some(StopMode::Stop1)
         } else {
             None
@@ -207,7 +271,7 @@ impl Executor {
 
     #[allow(unused_variables)]
     fn configure_stop(&mut self, stop_mode: StopMode) {
-        #[cfg(any(stm32l4, stm32l5, stm32u5, stm32u0, stm32wba))]
+        #[cfg(any(stm32l4, stm32l5, stm32u5, stm32u0, stm32wba, stm32wlex))]
         crate::pac::PWR.cr1().modify(|m| m.set_lpms(stop_mode.into()));
         #[cfg(stm32h5)]
         crate::pac::PWR.pmcr().modify(|v| {
@@ -219,6 +283,11 @@ impl Executor {
 
     fn configure_pwr(&mut self) {
         self.scb.clear_sleepdeep();
+        // Clear any previous stop flags
+        #[cfg(stm32wlex)]
+        crate::pac::PWR.extscr().modify(|w| {
+            w.set_c1cssf(true);
+        });
 
         compiler_fence(Ordering::SeqCst);
 
@@ -272,6 +341,19 @@ impl Executor {
                 executor.inner.poll();
                 self.configure_pwr();
                 asm!("wfe");
+                #[cfg(stm32wlex)]
+                {
+                    let es = crate::pac::PWR.extscr().read();
+                    match (es.c1stopf(), es.c1stop2f()) {
+                        (true, false) => debug!("low power: wake from STOP1"),
+                        (false, true) => debug!("low power: wake from STOP2"),
+                        (true, true) => debug!("low power: wake from STOP1 and STOP2 ???"),
+                        (false, false) => trace!("low power: stop mode not entered"),
+                    };
+                    crate::pac::PWR.extscr().modify(|w| {
+                        w.set_c1cssf(false);
+                    });
+                }
             };
         }
     }
diff --git a/embassy-stm32/src/rcc/l.rs b/embassy-stm32/src/rcc/l.rs
index 2e1cbd702..584957c6d 100644
--- a/embassy-stm32/src/rcc/l.rs
+++ b/embassy-stm32/src/rcc/l.rs
@@ -1,3 +1,6 @@
+#[cfg(all(feature = "low-power", stm32wlex))]
+use core::mem::MaybeUninit;
+
 #[cfg(any(stm32l0, stm32l1))]
 pub use crate::pac::pwr::vals::Vos as VoltageScale;
 use crate::pac::rcc::regs::Cfgr;
@@ -11,6 +14,42 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
+/// Saved RCC Config
+///
+/// Used when exiting STOP2 to re-enable clocks to their last configured state
+/// for chips that need it.
+#[cfg(all(feature = "low-power", stm32wlex))]
+static mut RESUME_RCC_CONFIG: MaybeUninit<Config> = MaybeUninit::uninit();
+
+/// Set the rcc config to be restored when exiting STOP2
+///
+/// Safety: Sets a mutable global.
+#[cfg(all(feature = "low-power", stm32wlex))]
+pub(crate) unsafe fn set_resume_config(config: Config) {
+    trace!("rcc set_resume_config()");
+    RESUME_RCC_CONFIG = MaybeUninit::new(config);
+}
+
+/// Get the rcc config to be restored when exiting STOP2
+///
+/// Safety: Reads a mutable global.
+#[cfg(all(feature = "low-power", stm32wlex))]
+pub(crate) unsafe fn get_resume_config() -> Config {
+    *(*core::ptr::addr_of_mut!(RESUME_RCC_CONFIG)).assume_init_ref()
+}
+
+#[cfg(all(feature = "low-power", stm32wlex))]
+/// Safety: should only be called from low power executable just after resuming from STOP2
+pub(crate) unsafe fn apply_resume_config() {
+    trace!("rcc apply_resume_config()");
+
+    while RCC.cfgr().read().sws() != Sysclk::MSI {}
+
+    let config = get_resume_config();
+
+    init(config);
+}
+
 #[derive(Clone, Copy, Eq, PartialEq)]
 pub enum HseMode {
     /// crystal/ceramic oscillator (HSEBYP=0)
@@ -154,6 +193,10 @@ fn msi_enable(range: MSIRange) {
 }
 
 pub(crate) unsafe fn init(config: Config) {
+    // save the rcc config because if we enter stop 2 we need to re-apply it on wakeup
+    #[cfg(all(feature = "low-power", stm32wlex))]
+    set_resume_config(config);
+
     // Switch to MSI to prevent problems with PLL configuration.
     if !RCC.cr().read().msion() {
         // Turn on MSI and configure it to 4MHz.
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index addfca3c3..c817dd4b7 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -390,7 +390,7 @@ pub fn disable<T: RccPeripheral>() {
 ///
 /// This should only be called after `init`.
 #[cfg(not(feature = "_dual-core"))]
-pub fn reinit<'a>(config: Config, _rcc: &'a mut crate::Peri<'a, crate::peripherals::RCC>) {
+pub fn reinit(config: Config, _rcc: &'_ mut crate::Peri<'_, crate::peripherals::RCC>) {
     critical_section::with(|cs| init_rcc(cs, config))
 }
 
diff --git a/embassy-stm32/src/rtc/low_power.rs b/embassy-stm32/src/rtc/low_power.rs
index 9e0f03879..e09d5afb0 100644
--- a/embassy-stm32/src/rtc/low_power.rs
+++ b/embassy-stm32/src/rtc/low_power.rs
@@ -68,7 +68,7 @@ pub(crate) enum WakeupPrescaler {
 }
 
 #[cfg(any(
-    stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba
+    stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba, stm32wlex
 ))]
 impl From<WakeupPrescaler> for crate::pac::rtc::vals::Wucksel {
     fn from(val: WakeupPrescaler) -> Self {
@@ -84,7 +84,7 @@ impl From<WakeupPrescaler> for crate::pac::rtc::vals::Wucksel {
 }
 
 #[cfg(any(
-    stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba
+    stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba, stm32wlex
 ))]
 impl From<crate::pac::rtc::vals::Wucksel> for WakeupPrescaler {
     fn from(val: crate::pac::rtc::vals::Wucksel) -> Self {
diff --git a/embassy-stm32/src/rtc/v3.rs b/embassy-stm32/src/rtc/v3.rs
index 528dc78b4..f7ebea73e 100644
--- a/embassy-stm32/src/rtc/v3.rs
+++ b/embassy-stm32/src/rtc/v3.rs
@@ -131,7 +131,7 @@ impl SealedInstance for crate::peripherals::RTC {
 
     #[cfg(feature = "low-power")]
     cfg_if::cfg_if!(
-        if #[cfg(stm32g4)] {
+        if #[cfg(any(stm32g4, stm32wlex))] {
             const EXTI_WAKEUP_LINE: usize = 20;
         } else if #[cfg(stm32g0)] {
             const EXTI_WAKEUP_LINE: usize = 19;
@@ -142,7 +142,7 @@ impl SealedInstance for crate::peripherals::RTC {
 
     #[cfg(feature = "low-power")]
     cfg_if::cfg_if!(
-        if #[cfg(stm32g4)] {
+        if #[cfg(any(stm32g4, stm32wlex))] {
             type WakeupInterrupt = crate::interrupt::typelevel::RTC_WKUP;
         } else if #[cfg(any(stm32g0, stm32u0))] {
             type WakeupInterrupt = crate::interrupt::typelevel::RTC_TAMP;
diff --git a/embassy-stm32/src/time_driver.rs b/embassy-stm32/src/time_driver.rs
index 7fd5751b3..4956d1f68 100644
--- a/embassy-stm32/src/time_driver.rs
+++ b/embassy-stm32/src/time_driver.rs
@@ -1,6 +1,8 @@
 #![allow(non_snake_case)]
 
 use core::cell::{Cell, RefCell};
+#[cfg(all(feature = "low-power", stm32wlex))]
+use core::sync::atomic::AtomicU16;
 use core::sync::atomic::{AtomicU32, Ordering, compiler_fence};
 
 use critical_section::CriticalSection;
@@ -214,6 +216,9 @@ pub(crate) struct RtcDriver {
     alarm: Mutex<CriticalSectionRawMutex, AlarmState>,
     #[cfg(feature = "low-power")]
     rtc: Mutex<CriticalSectionRawMutex, RefCell<Option<Rtc>>>,
+    /// Saved count for the timer (its value is lost when entering STOP2)
+    #[cfg(all(feature = "low-power", stm32wlex))]
+    saved_count: AtomicU16,
     queue: Mutex<CriticalSectionRawMutex, RefCell<Queue>>,
 }
 
@@ -222,11 +227,15 @@ embassy_time_driver::time_driver_impl!(static DRIVER: RtcDriver = RtcDriver {
     alarm: Mutex::const_new(CriticalSectionRawMutex::new(), AlarmState::new()),
     #[cfg(feature = "low-power")]
     rtc: Mutex::const_new(CriticalSectionRawMutex::new(), RefCell::new(None)),
+    #[cfg(all(feature = "low-power", stm32wlex))]
+    saved_count: AtomicU16::new(0),
     queue: Mutex::new(RefCell::new(Queue::new()))
 });
 
 impl RtcDriver {
-    fn init(&'static self, cs: critical_section::CriticalSection) {
+    /// initialize the timer, but don't start it.  Used for chips like stm32wle5
+    /// for low power where the timer config is lost in STOP2.
+    fn init_timer(&'static self, cs: critical_section::CriticalSection) {
         let r = regs_gp16();
 
         rcc::enable_and_reset_with_cs::<T>(cs);
@@ -259,10 +268,16 @@ impl RtcDriver {
             w.set_ccie(0, true);
         });
 
+        #[cfg(all(feature = "low-power", stm32wlex))]
+        r.cnt().write(|w| w.set_cnt(self.saved_count.load(Ordering::SeqCst)));
+
         <T as GeneralInstance1Channel>::CaptureCompareInterrupt::unpend();
         unsafe { <T as GeneralInstance1Channel>::CaptureCompareInterrupt::enable() };
+    }
 
-        r.cr1().modify(|w| w.set_cen(true));
+    fn init(&'static self, cs: CriticalSection) {
+        self.init_timer(cs);
+        regs_gp16().cr1().modify(|w| w.set_cen(true));
     }
 
     fn on_interrupt(&self) {
@@ -420,6 +435,10 @@ impl RtcDriver {
 
             let time_until_next_alarm = self.time_until_next_alarm(cs);
             if time_until_next_alarm < Self::MIN_STOP_PAUSE {
+                trace!(
+                    "time_until_next_alarm < Self::MIN_STOP_PAUSE ({})",
+                    time_until_next_alarm
+                );
                 Err(())
             } else {
                 self.rtc
@@ -430,7 +449,10 @@ impl RtcDriver {
                     .start_wakeup_alarm(time_until_next_alarm, cs);
 
                 regs_gp16().cr1().modify(|w| w.set_cen(false));
-
+                // save the count for the timer as its lost in STOP2 for stm32wlex
+                #[cfg(stm32wlex)]
+                self.saved_count
+                    .store(regs_gp16().cnt().read().cnt() as u16, Ordering::SeqCst);
                 Ok(())
             }
         })
@@ -528,3 +550,8 @@ pub(crate) fn get_driver() -> &'static RtcDriver {
 pub(crate) fn init(cs: CriticalSection) {
     DRIVER.init(cs)
 }
+
+#[cfg(all(feature = "low-power", stm32wlex))]
+pub(crate) fn init_timer(cs: CriticalSection) {
+    DRIVER.init_timer(cs)
+}
diff --git a/examples/stm32wle5/.cargo/config.toml b/examples/stm32wle5/.cargo/config.toml
new file mode 100644
index 000000000..0178d377c
--- /dev/null
+++ b/examples/stm32wle5/.cargo/config.toml
@@ -0,0 +1,9 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# replace your chip as listed in `probe-rs chip list`
+runner = "probe-rs run --chip STM32WLE5JCIx --connect-under-reset"
+
+[build]
+target = "thumbv7em-none-eabi"
+
+[env]
+DEFMT_LOG = "info"
diff --git a/examples/stm32wle5/Cargo.toml b/examples/stm32wle5/Cargo.toml
new file mode 100644
index 000000000..f2fc4dd3d
--- /dev/null
+++ b/examples/stm32wle5/Cargo.toml
@@ -0,0 +1,38 @@
+[package]
+edition = "2024"
+name = "embassy-stm32wl-examples"
+version = "0.1.0"
+license = "MIT OR Apache-2.0"
+publish = false
+
+[dependencies]
+# Change stm32wl55jc-cm4 to your chip name, if necessary.
+embassy-stm32 = { version = "0.4.0", path = "../../embassy-stm32", features = ["defmt", "stm32wle5jc", "time-driver-any", "memory-x", "unstable-pac", "exti", "low-power"] }
+embassy-sync = { version = "0.7.2", path = "../../embassy-sync", features = ["defmt"] }
+embassy-executor = { version = "0.9.0", path = "../../embassy-executor", features = ["arch-cortex-m", "executor-thread", "defmt"] }
+embassy-time = { version = "0.5.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-hz-1_000"] }
+embassy-embedded-hal = { version = "0.5.0", path = "../../embassy-embedded-hal" }
+
+defmt = "1.0.1"
+defmt-rtt = { version = "1.1.0", optional = true }
+defmt-serial = { version = "0.10.0", optional = true }
+
+cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-single-core"] }
+cortex-m-rt = "0.7.0"
+embedded-hal = "1.0.0"
+embedded-storage = "0.3.1"
+panic-probe = { version = "1.0.0", features = ["print-defmt"] }
+static_cell = { version = "2.1.1", default-features = false }
+
+[profile.release]
+debug = 2
+
+[package.metadata.embassy]
+build = [
+  { target = "thumbv7em-none-eabi", artifact-dir = "out/examples/stm32wl" }
+]
+
+[features]
+default = ["defmt-serial"]
+defmt-rtt = ["dep:defmt-rtt"]
+defmt-serial = ["dep:defmt-serial"]
diff --git a/examples/stm32wle5/README.md b/examples/stm32wle5/README.md
new file mode 100644
index 000000000..18c3b5071
--- /dev/null
+++ b/examples/stm32wle5/README.md
@@ -0,0 +1,52 @@
+# Low Power Examples for STM32WLEx family
+
+Examples in this repo should work with [LoRa-E5 Dev Board](https://www.st.com/en/partner-products-and-services/lora-e5-development-kit.html) board.
+
+## Prerequsits
+
+- Connect a usb serial adapter to LPUart1 (this is where ALL logging will go)
+- Optional: Connect an amp meter that ran measure down to 0.1uA to the power test pins
+- `cargo install defmt-print` so you can print log messahes from LPUart1
+
+## Example Notes
+
+All examples will set all pins to analog mode before configuring pins for the example, if any. This saves about 500uA!!!!
+
+- the `adc` example will sleep in STOP1 betwen samples and the chip will only draw about 13uA while sleeping
+- the `blinky` example will sleep in STOP2 and the chip will only draw 1uA or less while sleeping
+- the `button_exti` example will sleep in STOP2 and the chip will only draw 1uA or less while sleeping
+- the `i2c` examples will sleep in STOP1 between reads and the chip only draw about 10uA while sleeping
+
+For each example you will need to start `defmt-print` with the example binary and the correct serial port in a seperate terminal.  Example:
+```
+defmt-print -w -v -e target/thumbv7em-none-eabi/debug/<module-name> serial --path /dev/cu.usbserial-00000000 --baud 115200
+```
+
+Run individual examples with
+```
+cargo flash --chip STM32WLE5JCIx --connect-under-reset --bin <module-name>
+```
+for example
+```
+cargo flash --chip STM32WLE5JCIx --connect-under-reset --bin blinky
+```
+
+You can also run them with with `run`.  However in this case expect probe-rs to be disconnected as soon as flashing is done as all IO pins are set to analog input!
+```
+cargo run --bin blinky
+```
+
+## Checklist before running examples
+You might need to adjust `.cargo/config.toml`, `Cargo.toml` and possibly update pin numbers or peripherals to match the specific MCU or board you are using.
+
+* [ ] Update .cargo/config.toml with the correct probe-rs command to use your specific MCU. For example for L432KCU6 it should be `probe-rs run --chip STM32L432KCUx`. (use `probe-rs chip list` to find your chip)
+* [ ] Update Cargo.toml to have the correct `embassy-stm32` feature. For example for L432KCU6 it should be `stm32l432kc`. Look in the `Cargo.toml` file of the `embassy-stm32` project to find the correct feature flag for your chip.
+* [ ] If your board has a special clock or power configuration, make sure that it is set up appropriately.
+* [ ] If your board has different pin mapping, update any pin numbers or peripherals in the given example code to match your schematic
+
+If you are unsure, please drop by the Embassy Matrix chat for support, and let us know:
+
+* Which example you are trying to run
+* Which chip and board you are using
+
+Embassy Chat: https://matrix.to/#/#embassy-rs:matrix.org
diff --git a/examples/stm32wle5/build.rs b/examples/stm32wle5/build.rs
new file mode 100644
index 000000000..8cd32d7ed
--- /dev/null
+++ b/examples/stm32wle5/build.rs
@@ -0,0 +1,5 @@
+fn main() {
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}
diff --git a/examples/stm32wle5/src/bin/adc.rs b/examples/stm32wle5/src/bin/adc.rs
new file mode 100644
index 000000000..ff1a5fa16
--- /dev/null
+++ b/examples/stm32wle5/src/bin/adc.rs
@@ -0,0 +1,100 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+#[cfg(feature = "defmt-rtt")]
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::adc::{Adc, SampleTime};
+use embassy_stm32::low_power::Executor;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
+use embassy_time::Timer;
+use panic_probe as _;
+use static_cell::StaticCell;
+
+#[cortex_m_rt::entry]
+fn main() -> ! {
+    info!("main: Starting!");
+    Executor::take().run(|spawner| {
+        spawner.spawn(unwrap!(async_main(spawner)));
+    });
+}
+
+#[embassy_executor::task]
+async fn async_main(_spawner: Spawner) {
+    let mut config = embassy_stm32::Config::default();
+    // enable HSI clock
+    config.rcc.hsi = true;
+    // enable LSI clock for RTC
+    config.rcc.ls = embassy_stm32::rcc::LsConfig::default_lsi();
+    config.rcc.msi = Some(embassy_stm32::rcc::MSIRange::RANGE4M);
+    config.rcc.sys = embassy_stm32::rcc::Sysclk::MSI;
+    // enable ADC with HSI clock
+    config.rcc.mux.adcsel = embassy_stm32::pac::rcc::vals::Adcsel::HSI;
+    #[cfg(feature = "defmt-serial")]
+    {
+        // disable debug during sleep to reduce power consumption since we are
+        // using defmt-serial on LPUART1.
+        config.enable_debug_during_sleep = false;
+        // if we are using defmt-serial on LPUART1, we need to use HSI for the clock
+        // so that its registers are preserved during STOP modes.
+        config.rcc.mux.lpuart1sel = embassy_stm32::pac::rcc::vals::Lpuart1sel::HSI;
+    }
+    // Initialize STM32WL peripherals (use default config like wio-e5-async example)
+    let p = embassy_stm32::init(config);
+
+    // start with all GPIOs as analog to reduce power consumption
+    for r in [
+        embassy_stm32::pac::GPIOA,
+        embassy_stm32::pac::GPIOB,
+        embassy_stm32::pac::GPIOC,
+        embassy_stm32::pac::GPIOH,
+    ] {
+        r.moder().modify(|w| {
+            for i in 0..16 {
+                // don't reset these if probe-rs should stay connected!
+                #[cfg(feature = "defmt-rtt")]
+                if config.enable_debug_during_sleep && r == embassy_stm32::pac::GPIOA && [13, 14].contains(&i) {
+                    continue;
+                }
+                w.set_moder(i, embassy_stm32::pac::gpio::vals::Moder::ANALOG);
+            }
+        });
+    }
+    #[cfg(feature = "defmt-serial")]
+    {
+        use embassy_stm32::mode::Blocking;
+        use embassy_stm32::usart::Uart;
+        let config = embassy_stm32::usart::Config::default();
+        let uart = Uart::new_blocking(p.LPUART1, p.PC0, p.PC1, config).expect("failed to configure UART!");
+        static SERIAL: StaticCell<Uart<'static, Blocking>> = StaticCell::new();
+        defmt_serial::defmt_serial(SERIAL.init(uart));
+    }
+
+    // give the RTC to the low_power executor...
+    let rtc_config = RtcConfig::default();
+    let rtc = Rtc::new(p.RTC, rtc_config);
+    embassy_stm32::low_power::stop_with_rtc(rtc);
+
+    info!("Hello World!");
+
+    let mut adc = Adc::new(p.ADC1);
+    adc.set_sample_time(SampleTime::CYCLES79_5);
+    let mut pin = p.PA10;
+
+    let mut vrefint = adc.enable_vrefint();
+    let vrefint_sample = adc.blocking_read(&mut vrefint);
+    let convert_to_millivolts = |sample| {
+        // From https://www.st.com/resource/en/datasheet/stm32g031g8.pdf
+        // 6.3.3 Embedded internal reference voltage
+        const VREFINT_MV: u32 = 1212; // mV
+
+        (u32::from(sample) * VREFINT_MV / u32::from(vrefint_sample)) as u16
+    };
+
+    loop {
+        let v = adc.blocking_read(&mut pin);
+        info!("--> {} - {} mV", v, convert_to_millivolts(v));
+        Timer::after_secs(1).await;
+    }
+}
diff --git a/examples/stm32wle5/src/bin/blinky.rs b/examples/stm32wle5/src/bin/blinky.rs
new file mode 100644
index 000000000..1191a1157
--- /dev/null
+++ b/examples/stm32wle5/src/bin/blinky.rs
@@ -0,0 +1,90 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+#[cfg(feature = "defmt-rtt")]
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_stm32::low_power::Executor;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
+use embassy_time::Timer;
+use panic_probe as _;
+use static_cell::StaticCell;
+
+#[cortex_m_rt::entry]
+fn main() -> ! {
+    info!("main: Starting!");
+    Executor::take().run(|spawner| {
+        spawner.spawn(unwrap!(async_main(spawner)));
+    });
+}
+
+#[embassy_executor::task]
+async fn async_main(_spawner: Spawner) {
+    let mut config = embassy_stm32::Config::default();
+    // enable HSI clock
+    config.rcc.hsi = true;
+    // enable LSI clock for RTC
+    config.rcc.ls = embassy_stm32::rcc::LsConfig::default_lsi();
+    config.rcc.msi = Some(embassy_stm32::rcc::MSIRange::RANGE4M);
+    config.rcc.sys = embassy_stm32::rcc::Sysclk::MSI;
+    #[cfg(feature = "defmt-serial")]
+    {
+        // disable debug during sleep to reduce power consumption since we are
+        // using defmt-serial on LPUART1.
+        config.enable_debug_during_sleep = false;
+        // if we are using defmt-serial on LPUART1, we need to use HSI for the clock
+        // so that its registers are preserved during STOP modes.
+        config.rcc.mux.lpuart1sel = embassy_stm32::pac::rcc::vals::Lpuart1sel::HSI;
+    }
+    // Initialize STM32WL peripherals (use default config like wio-e5-async example)
+    let p = embassy_stm32::init(config);
+
+    // start with all GPIOs as analog to reduce power consumption
+    for r in [
+        embassy_stm32::pac::GPIOA,
+        embassy_stm32::pac::GPIOB,
+        embassy_stm32::pac::GPIOC,
+        embassy_stm32::pac::GPIOH,
+    ] {
+        r.moder().modify(|w| {
+            for i in 0..16 {
+                // don't reset these if probe-rs should stay connected!
+                #[cfg(feature = "defmt-rtt")]
+                if config.enable_debug_during_sleep && r == embassy_stm32::pac::GPIOA && [13, 14].contains(&i) {
+                    continue;
+                }
+                w.set_moder(i, embassy_stm32::pac::gpio::vals::Moder::ANALOG);
+            }
+        });
+    }
+    #[cfg(feature = "defmt-serial")]
+    {
+        use embassy_stm32::mode::Blocking;
+        use embassy_stm32::usart::Uart;
+        let config = embassy_stm32::usart::Config::default();
+        let uart = Uart::new_blocking(p.LPUART1, p.PC0, p.PC1, config).expect("failed to configure UART!");
+        static SERIAL: StaticCell<Uart<'static, Blocking>> = StaticCell::new();
+        defmt_serial::defmt_serial(SERIAL.init(uart));
+    }
+
+    // give the RTC to the low_power executor...
+    let rtc_config = RtcConfig::default();
+    let rtc = Rtc::new(p.RTC, rtc_config);
+    embassy_stm32::low_power::stop_with_rtc(rtc);
+
+    info!("Hello World!");
+
+    let mut led = Output::new(p.PB5, Level::High, Speed::Low);
+
+    loop {
+        info!("low");
+        led.set_low();
+        Timer::after_millis(500).await;
+
+        info!("high");
+        led.set_high();
+        Timer::after_millis(500).await;
+    }
+}
diff --git a/examples/stm32wle5/src/bin/button_exti.rs b/examples/stm32wle5/src/bin/button_exti.rs
new file mode 100644
index 000000000..f07f9724d
--- /dev/null
+++ b/examples/stm32wle5/src/bin/button_exti.rs
@@ -0,0 +1,91 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+#[cfg(feature = "defmt-rtt")]
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::exti::ExtiInput;
+use embassy_stm32::gpio::Pull;
+use embassy_stm32::low_power::Executor;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
+use panic_probe as _;
+use static_cell::StaticCell;
+
+#[cortex_m_rt::entry]
+fn main() -> ! {
+    info!("main: Starting!");
+    Executor::take().run(|spawner| {
+        spawner.spawn(unwrap!(async_main(spawner)));
+    });
+}
+
+#[embassy_executor::task]
+async fn async_main(_spawner: Spawner) {
+    let mut config = embassy_stm32::Config::default();
+    // enable HSI clock
+    config.rcc.hsi = true;
+    // enable LSI clock for RTC
+    config.rcc.ls = embassy_stm32::rcc::LsConfig::default_lsi();
+    config.rcc.msi = Some(embassy_stm32::rcc::MSIRange::RANGE4M);
+    config.rcc.sys = embassy_stm32::rcc::Sysclk::MSI;
+    // enable ADC with HSI clock
+    config.rcc.mux.adcsel = embassy_stm32::pac::rcc::vals::Adcsel::HSI;
+    #[cfg(feature = "defmt-serial")]
+    {
+        // disable debug during sleep to reduce power consumption since we are
+        // using defmt-serial on LPUART1.
+        config.enable_debug_during_sleep = false;
+        // if we are using defmt-serial on LPUART1, we need to use HSI for the clock
+        // so that its registers are preserved during STOP modes.
+        config.rcc.mux.lpuart1sel = embassy_stm32::pac::rcc::vals::Lpuart1sel::HSI;
+    }
+    // Initialize STM32WL peripherals (use default config like wio-e5-async example)
+    let p = embassy_stm32::init(config);
+
+    // start with all GPIOs as analog to reduce power consumption
+    for r in [
+        embassy_stm32::pac::GPIOA,
+        embassy_stm32::pac::GPIOB,
+        embassy_stm32::pac::GPIOC,
+        embassy_stm32::pac::GPIOH,
+    ] {
+        r.moder().modify(|w| {
+            for i in 0..16 {
+                // don't reset these if probe-rs should stay connected!
+                #[cfg(feature = "defmt-rtt")]
+                if config.enable_debug_during_sleep && r == embassy_stm32::pac::GPIOA && [13, 14].contains(&i) {
+                    continue;
+                }
+                w.set_moder(i, embassy_stm32::pac::gpio::vals::Moder::ANALOG);
+            }
+        });
+    }
+    #[cfg(feature = "defmt-serial")]
+    {
+        use embassy_stm32::mode::Blocking;
+        use embassy_stm32::usart::Uart;
+        let config = embassy_stm32::usart::Config::default();
+        let uart = Uart::new_blocking(p.LPUART1, p.PC0, p.PC1, config).expect("failed to configure UART!");
+        static SERIAL: StaticCell<Uart<'static, Blocking>> = StaticCell::new();
+        defmt_serial::defmt_serial(SERIAL.init(uart));
+    }
+
+    // give the RTC to the low_power executor...
+    let rtc_config = RtcConfig::default();
+    let rtc = Rtc::new(p.RTC, rtc_config);
+    embassy_stm32::low_power::stop_with_rtc(rtc);
+
+    info!("Hello World!");
+
+    let mut button = ExtiInput::new(p.PA0, p.EXTI0, Pull::Up);
+
+    info!("Press the USER button...");
+
+    loop {
+        button.wait_for_falling_edge().await;
+        info!("Pressed!");
+        button.wait_for_rising_edge().await;
+        info!("Released!");
+    }
+}
diff --git a/examples/stm32wle5/src/bin/i2c.rs b/examples/stm32wle5/src/bin/i2c.rs
new file mode 100644
index 000000000..af07f911e
--- /dev/null
+++ b/examples/stm32wle5/src/bin/i2c.rs
@@ -0,0 +1,110 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+#[cfg(feature = "defmt-rtt")]
+use defmt_rtt as _;
+use embassy_executor::Spawner;
+use embassy_stm32::i2c::I2c;
+use embassy_stm32::low_power::Executor;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
+use embassy_stm32::time::Hertz;
+use embassy_stm32::{bind_interrupts, i2c, peripherals};
+use embassy_time::{Duration, Timer};
+use panic_probe as _;
+use static_cell::StaticCell;
+
+bind_interrupts!(struct IrqsI2C{
+    I2C2_EV => i2c::EventInterruptHandler<peripherals::I2C2>;
+    I2C2_ER => i2c::ErrorInterruptHandler<peripherals::I2C2>;
+});
+
+#[cortex_m_rt::entry]
+fn main() -> ! {
+    info!("main: Starting!");
+    Executor::take().run(|spawner| {
+        spawner.spawn(unwrap!(async_main(spawner)));
+    });
+}
+
+#[embassy_executor::task]
+async fn async_main(_spawner: Spawner) {
+    let mut config = embassy_stm32::Config::default();
+    // enable HSI clock
+    config.rcc.hsi = true;
+    // enable LSI clock for RTC
+    config.rcc.ls = embassy_stm32::rcc::LsConfig::default_lsi();
+    config.rcc.msi = Some(embassy_stm32::rcc::MSIRange::RANGE4M);
+    config.rcc.sys = embassy_stm32::rcc::Sysclk::MSI;
+    // enable ADC with HSI clock
+    config.rcc.mux.i2c2sel = embassy_stm32::pac::rcc::vals::I2c2sel::HSI;
+    #[cfg(feature = "defmt-serial")]
+    {
+        // disable debug during sleep to reduce power consumption since we are
+        // using defmt-serial on LPUART1.
+        config.enable_debug_during_sleep = false;
+        // if we are using defmt-serial on LPUART1, we need to use HSI for the clock
+        // so that its registers are preserved during STOP modes.
+        config.rcc.mux.lpuart1sel = embassy_stm32::pac::rcc::vals::Lpuart1sel::HSI;
+    }
+    // Initialize STM32WL peripherals (use default config like wio-e5-async example)
+    let p = embassy_stm32::init(config);
+
+    // start with all GPIOs as analog to reduce power consumption
+    for r in [
+        embassy_stm32::pac::GPIOA,
+        embassy_stm32::pac::GPIOB,
+        embassy_stm32::pac::GPIOC,
+        embassy_stm32::pac::GPIOH,
+    ] {
+        r.moder().modify(|w| {
+            for i in 0..16 {
+                // don't reset these if probe-rs should stay connected!
+                #[cfg(feature = "defmt-rtt")]
+                if config.enable_debug_during_sleep && r == embassy_stm32::pac::GPIOA && [13, 14].contains(&i) {
+                    continue;
+                }
+                w.set_moder(i, embassy_stm32::pac::gpio::vals::Moder::ANALOG);
+            }
+        });
+    }
+    #[cfg(feature = "defmt-serial")]
+    {
+        use embassy_stm32::mode::Blocking;
+        use embassy_stm32::usart::Uart;
+        let config = embassy_stm32::usart::Config::default();
+        let uart = Uart::new_blocking(p.LPUART1, p.PC0, p.PC1, config).expect("failed to configure UART!");
+        static SERIAL: StaticCell<Uart<'static, Blocking>> = StaticCell::new();
+        defmt_serial::defmt_serial(SERIAL.init(uart));
+    }
+
+    // give the RTC to the low_power executor...
+    let rtc_config = RtcConfig::default();
+    let rtc = Rtc::new(p.RTC, rtc_config);
+    embassy_stm32::low_power::stop_with_rtc(rtc);
+
+    info!("Hello World!");
+    let en3v3 = embassy_stm32::gpio::Output::new(
+        p.PA9,
+        embassy_stm32::gpio::Level::High,
+        embassy_stm32::gpio::Speed::High,
+    );
+    core::mem::forget(en3v3); // keep the output pin enabled
+
+    let mut i2c = I2c::new(p.I2C2, p.PB15, p.PA15, IrqsI2C, p.DMA1_CH6, p.DMA1_CH7, {
+        let mut config = i2c::Config::default();
+        config.frequency = Hertz::khz(100);
+        config.timeout = Duration::from_millis(500);
+        config
+    });
+
+    loop {
+        let mut buffer = [0; 2];
+        // read the temperature register of the onboard lm75
+        match i2c.read(0x48, &mut buffer).await {
+            Ok(_) => info!("--> {:?}", buffer),
+            Err(e) => info!("--> Error: {:?}", e),
+        }
+        Timer::after_secs(5).await;
+    }
+}
diff --git a/examples/stm32wle5/stm32wle5.code-workspace b/examples/stm32wle5/stm32wle5.code-workspace
new file mode 100644
index 000000000..a7c4a0ebd
--- /dev/null
+++ b/examples/stm32wle5/stm32wle5.code-workspace
@@ -0,0 +1,13 @@
+{
+        "folders": [
+                {
+                        "path": "."
+                }
+        ],
+        "settings": {
+                "rust-analyzer.cargo.target": "thumbv7em-none-eabi",
+                "rust-analyzer.cargo.allTargets": false,
+                "rust-analyzer.cargo.targetDir": "target/rust-analyzer",
+                "rust-analyzer.checkOnSave": true,
+        }
+}