From 1bcc66edead224b43499cdb9df00e62817636f9e Mon Sep 17 00:00:00 2001
From: xoviat <xoviat@users.noreply.github.com>
Date: Fri, 21 Nov 2025 11:28:57 -0600
Subject: [PATCH] cycle usart on idle termination

fixes #4689.
fixes #3900.
---
 embassy-stm32/CHANGELOG.md     | 1 +
 embassy-stm32/src/usart/mod.rs | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/embassy-stm32/CHANGELOG.md b/embassy-stm32/CHANGELOG.md
index 597cbb1921..f15a5ac433 100644
--- a/embassy-stm32/CHANGELOG.md
+++ b/embassy-stm32/CHANGELOG.md
@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased - ReleaseDate
 
+- fix: cycle usart on idle termination
 - change: rework hsem and add HIL test for some chips.
 - change: stm32/eth: ethernet no longer has a hard dependency on station management, and station management can be used independently ([#4871](https://github.com/embassy-rs/embassy/pull/4871))
 - feat: allow embassy_executor::main for low power
diff --git a/embassy-stm32/src/usart/mod.rs b/embassy-stm32/src/usart/mod.rs
index 0e7da634df..45b09ec00f 100644
--- a/embassy-stm32/src/usart/mod.rs
+++ b/embassy-stm32/src/usart/mod.rs
@@ -765,6 +765,8 @@ impl<'d> UartRx<'d, Async> {
                 w.set_peie(false);
                 // disable idle line interrupt
                 w.set_idleie(false);
+                // disable uart to clear any data present
+                w.set_ue(!enable_idle_line_detection)
             });
             r.cr3().modify(|w| {
                 // disable Error Interrupt: (Frame error, Noise error, Overrun error)
@@ -772,6 +774,8 @@ impl<'d> UartRx<'d, Async> {
                 // disable DMA Rx Request
                 w.set_dmar(false);
             });
+
+            r.cr1().modify(|w| w.set_ue(true));
         });
 
         let ch = self.rx_dma.as_mut().unwrap();