Don't read data register to clear flags on usart v3 ^& v4

1 files changed, 4 insertions, 2 deletions

diff --git a/embassy-stm32/src/usart/buffered.rs b/embassy-stm32/src/usart/buffered.rs
index 530760bd1..086196a2c 100644
--- a/embassy-stm32/src/usart/buffered.rs
+++ b/embassy-stm32/src/usart/buffered.rs
@@ -21,8 +21,10 @@ impl<T: BasicInstance> interrupt::typelevel::Handler<T::Interrupt> for Interrupt
         // RX
         unsafe {
             let sr = sr(r).read();
-            // Reading DR clears the rxne, error and idle interrupt flags on v1.
-            let dr = if sr.ore() || sr.idle() || sr.rxne() {
+            // On v1 & v2, reading DR clears the rxne, error and idle interrupt
+            // flags. Keep this close to the SR read to reduce the chance of a
+            // flag being set in-between.
+            let dr = if sr.rxne() || cfg!(any(usart_v1, usart_v2)) && (sr.ore() || sr.idle()) {
                 Some(rdr(r).read_volatile())
             } else {
                 None