fix low-power: APB1 needed for LSE

2 files changed, 5 insertions, 2 deletions

diff --git a/embassy-stm32/src/rcc/bd.rs b/embassy-stm32/src/rcc/bd.rs
index 762e84355..4915d5e2a 100644
--- a/embassy-stm32/src/rcc/bd.rs
+++ b/embassy-stm32/src/rcc/bd.rs
@@ -88,6 +88,11 @@ impl BackupDomain {
     ))]
     #[allow(dead_code, unused_variables)]
     pub fn configure_ls(clock_source: RtcClockSource, lsi: bool, lse: Option<LseDrive>) {
+        if lsi || lse.is_some() {
+            use crate::rtc::sealed::Instance;
+            crate::peripherals::RTC::enable_peripheral_clk();
+        }
+
         if lsi {
             #[cfg(rtc_v3u5)]
             let csr = crate::pac::RCC.bdcr();
diff --git a/embassy-stm32/src/rtc/mod.rs b/embassy-stm32/src/rtc/mod.rs
index 07b4fe1f0..7eafedec4 100644
--- a/embassy-stm32/src/rtc/mod.rs
+++ b/embassy-stm32/src/rtc/mod.rs
@@ -154,8 +154,6 @@ impl Default for RtcCalibrationCyclePeriod {
 
 impl Rtc {
     pub fn new(_rtc: impl Peripheral<P = RTC>, rtc_config: RtcConfig) -> Self {
-        RTC::enable_peripheral_clk();
-
         let mut this = Self {
             #[cfg(feature = "low-power")]
             stop_time: Mutex::const_new(CriticalSectionRawMutex::new(), Cell::new(None)),