diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 226293a9d..3e84d3386 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -600,17 +600,7 @@ fn init_hw(config: Config) -> Peripherals {
             #[cfg(feature = "exti")]
             exti::init(cs);
 
-            rcc::init(config.rcc);
-
-            // must be after rcc init
-            #[cfg(feature = "_time-driver")]
-            time_driver::init(cs);
-
-            #[cfg(feature = "low-power")]
-            {
-                crate::rcc::REFCOUNT_STOP2 = 0;
-                crate::rcc::REFCOUNT_STOP1 = 0;
-            }
+            rcc::init_rcc(cs, config.rcc);
         }
 
         p
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index 150daa4a7..3733fed56 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -371,3 +371,32 @@ pub fn enable_and_reset<T: RccPeripheral>() {
 pub fn disable<T: RccPeripheral>() {
     T::RCC_INFO.disable();
 }
+
+/// Re-initialize the `embassy-stm32` clock configuration with the provided configuration.
+///
+/// This is useful when you need to alter the CPU clock after configuring peripherals.
+/// For instance, configure an external clock via spi or i2c.
+///
+/// Please not this only re-configures the rcc and the time driver (not GPIO, EXTI, etc).
+///
+/// This should only be called after `init`.
+#[cfg(not(feature = "_dual-core"))]
+pub fn reinit(config: Config) {
+    critical_section::with(|cs| init_rcc(cs, config))
+}
+
+pub(crate) fn init_rcc(_cs: CriticalSection, config: Config) {
+    unsafe {
+        init(config);
+
+        // must be after rcc init
+        #[cfg(feature = "_time-driver")]
+        crate::time_driver::init(_cs);
+
+        #[cfg(feature = "low-power")]
+        {
+            REFCOUNT_STOP2 = 0;
+            REFCOUNT_STOP1 = 0;
+        }
+    }
+}