6 files changed, 36 insertions, 26 deletions

diff --git a/embassy-stm32/src/exti.rs b/embassy-stm32/src/exti.rs
index 7b7896d46..458174b5d 100644
--- a/embassy-stm32/src/exti.rs
+++ b/embassy-stm32/src/exti.rs
@@ -74,7 +74,7 @@ unsafe fn on_irq() {
     }
 
     #[cfg(feature = "low-power")]
-    crate::low_power::Executor::on_wakeup_irq();
+    crate::low_power::Executor::on_wakeup_irq_or_event();
 }
 
 struct BitIter(u32);
diff --git a/embassy-stm32/src/i2c/v2.rs b/embassy-stm32/src/i2c/v2.rs
index 6b213484c..7ad9978b1 100644
--- a/embassy-stm32/src/i2c/v2.rs
+++ b/embassy-stm32/src/i2c/v2.rs
@@ -73,7 +73,7 @@ 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::Executor::on_wakeup_irq();
+    crate::low_power::Executor::on_wakeup_irq_or_event();
 
     let regs = T::info().regs;
     let isr = regs.isr().read();
diff --git a/embassy-stm32/src/low_power.rs b/embassy-stm32/src/low_power.rs
index cdf3323fb..94217f07f 100644
--- a/embassy-stm32/src/low_power.rs
+++ b/embassy-stm32/src/low_power.rs
@@ -88,7 +88,7 @@ foreach_interrupt! {
         #[interrupt]
         #[allow(non_snake_case)]
         unsafe fn $irq() {
-            Executor::on_wakeup_irq();
+            Executor::on_wakeup_irq_or_event();
         }
     };
 }
@@ -99,7 +99,7 @@ foreach_interrupt! {
         #[interrupt]
         #[allow(non_snake_case)]
         unsafe fn $irq() {
-            Executor::on_wakeup_irq();
+            Executor::on_wakeup_irq_or_event();
         }
     };
 }
@@ -164,7 +164,11 @@ impl Executor {
         }
     }
 
-    pub(crate) unsafe fn on_wakeup_irq() {
+    pub(crate) unsafe fn on_wakeup_irq_or_event() {
+        if !get_driver().is_stopped() {
+            return;
+        }
+
         critical_section::with(|cs| {
             #[cfg(stm32wlex)]
             {
@@ -172,6 +176,17 @@ impl Executor {
                 use crate::pac::{PWR, RCC};
                 use crate::rcc::init as init_rcc;
 
+                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);
+                });
+
                 let extscr = PWR.extscr().read();
                 if extscr.c1stop2f() || extscr.c1stopf() {
                     // when we wake from any stop mode we need to re-initialize the rcc
@@ -190,7 +205,8 @@ impl Executor {
                 }
             }
             get_driver().resume_time(cs);
-            trace!("low power: resume");
+
+            trace!("low power: resume time");
         });
     }
 
@@ -201,10 +217,8 @@ impl Executor {
     fn stop_mode(_cs: CriticalSection) -> Option<StopMode> {
         // We cannot enter standby because we will lose program state.
         if unsafe { REFCOUNT_STOP2 == 0 && REFCOUNT_STOP1 == 0 } {
-            trace!("low power: stop 2");
             Some(StopMode::Stop2)
         } else if unsafe { REFCOUNT_STOP1 == 0 } {
-            trace!("low power: stop 1");
             Some(StopMode::Stop1)
         } else {
             trace!("low power: not ready to stop (refcount_stop1: {})", unsafe {
@@ -305,9 +319,11 @@ impl Executor {
             get_driver().pause_time(cs).ok()?;
             self.configure_stop(cs, stop_mode).ok()?;
 
-            Some(())
+            Some(stop_mode)
         })
-        .map(|_| {
+        .map(|stop_mode| {
+            trace!("low power: enter stop: {}", stop_mode);
+
             #[cfg(not(feature = "low-power-debug-with-sleep"))]
             Self::get_scb().set_sleepdeep();
         });
@@ -339,19 +355,7 @@ impl Executor {
                 self.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);
-                    });
-                }
+                Self::on_wakeup_irq_or_event();
             };
         }
     }
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index 1dd634cfe..5890e68f4 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -172,7 +172,7 @@ pub(crate) struct RccInfo {
 /// E.g. if `StopMode::Stop1` is selected, the peripheral prevents the chip from entering Stop1 mode.
 #[cfg(feature = "low-power")]
 #[allow(dead_code)]
-#[derive(Debug, Clone, Copy, PartialEq, Default)]
+#[derive(Debug, Clone, Copy, PartialEq, Default, defmt::Format)]
 pub enum StopMode {
     #[default]
     /// Peripheral prevents chip from entering Stop1 or executor will enter Stop1
diff --git a/embassy-stm32/src/time_driver.rs b/embassy-stm32/src/time_driver.rs
index cfcf5f3fd..ed5d902bd 100644
--- a/embassy-stm32/src/time_driver.rs
+++ b/embassy-stm32/src/time_driver.rs
@@ -329,6 +329,12 @@ impl RtcDriver {
         regs_gp16().cr1().modify(|w| w.set_cen(true));
     }
 
+    #[cfg(feature = "low-power")]
+    /// Returns whether time is currently stopped
+    pub(crate) fn is_stopped(&self) -> bool {
+        !regs_gp16().cr1().read().cen()
+    }
+
     fn set_alarm(&self, cs: CriticalSection, timestamp: u64) -> bool {
         let r = regs_gp16();
 
diff --git a/embassy-stm32/src/timer/mod.rs b/embassy-stm32/src/timer/mod.rs
index 74d1c9e77..998e3a6f4 100644
--- a/embassy-stm32/src/timer/mod.rs
+++ b/embassy-stm32/src/timer/mod.rs
@@ -406,7 +406,7 @@ pub struct UpdateInterruptHandler<T: CoreInstance> {
 impl<T: CoreInstance> interrupt::typelevel::Handler<T::UpdateInterrupt> for UpdateInterruptHandler<T> {
     unsafe fn on_interrupt() {
         #[cfg(feature = "low-power")]
-        crate::low_power::Executor::on_wakeup_irq();
+        crate::low_power::Executor::on_wakeup_irq_or_event();
 
         let regs = crate::pac::timer::TimCore::from_ptr(T::regs());
 
@@ -436,7 +436,7 @@ impl<T: GeneralInstance1Channel> interrupt::typelevel::Handler<T::CaptureCompare
 {
     unsafe fn on_interrupt() {
         #[cfg(feature = "low-power")]
-        crate::low_power::Executor::on_wakeup_irq();
+        crate::low_power::Executor::on_wakeup_irq_or_event();
 
         let regs = crate::pac::timer::TimGp16::from_ptr(T::regs());