2 files changed, 84 insertions, 23 deletions

diff --git a/embassy-stm32/Cargo.toml b/embassy-stm32/Cargo.toml
index 9566dbcaf..fbe37fe3d 100644
--- a/embassy-stm32/Cargo.toml
+++ b/embassy-stm32/Cargo.toml
@@ -44,6 +44,7 @@ embassy-usb-driver = {version = "0.1.0", path = "../embassy-usb-driver", optiona
 embedded-hal-02 = { package = "embedded-hal", version = "0.2.6", features = ["unproven"] }
 embedded-hal-1 = { package = "embedded-hal", version = "=1.0.0-alpha.9", optional = true}
 embedded-hal-async = { version = "=0.1.0-alpha.2", optional = true}
+embedded-hal-nb = { version = "=1.0.0-alpha.1", optional = true}
 
 embedded-storage = "0.3.0"
 embedded-storage-async = { version = "0.3.0", optional = true }
@@ -102,7 +103,7 @@ unstable-pac = []
 
 # Implement embedded-hal 1.0 alpha traits.
 # Implement embedded-hal-async traits if `nightly` is set as well.
-unstable-traits = ["embedded-hal-1"]
+unstable-traits = ["embedded-hal-1", "dep:embedded-hal-nb"]
 
 # BEGIN GENERATED FEATURES
 # Generated by stm32-gen-features. DO NOT EDIT.
diff --git a/embassy-stm32/src/usart/mod.rs b/embassy-stm32/src/usart/mod.rs
index 6c2668748..a152a0c15 100644
--- a/embassy-stm32/src/usart/mod.rs
+++ b/embassy-stm32/src/usart/mod.rs
@@ -160,6 +160,30 @@ impl<'d, T: BasicInstance, RxDma> UartRx<'d, T, RxDma> {
         Ok(())
     }
 
+    pub fn nb_read(&mut self) -> Result<u8, nb::Error<Error>> {
+        let r = T::regs();
+        unsafe {
+            let sr = sr(r).read();
+            if sr.pe() {
+                rdr(r).read_volatile();
+                Err(nb::Error::Other(Error::Parity))
+            } else if sr.fe() {
+                rdr(r).read_volatile();
+                Err(nb::Error::Other(Error::Framing))
+            } else if sr.ne() {
+                rdr(r).read_volatile();
+                Err(nb::Error::Other(Error::Noise))
+            } else if sr.ore() {
+                rdr(r).read_volatile();
+                Err(nb::Error::Other(Error::Overrun))
+            } else if sr.rxne() {
+                Ok(rdr(r).read_volatile())
+            } else {
+                Err(nb::Error::WouldBlock)
+            }
+        }
+    }
+
     pub fn blocking_read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
         unsafe {
             let r = T::regs();
@@ -263,6 +287,10 @@ impl<'d, T: BasicInstance, TxDma, RxDma> Uart<'d, T, TxDma, RxDma> {
         self.rx.read(buffer).await
     }
 
+    pub fn nb_read(&mut self) -> Result<u8, nb::Error<Error>> {
+        self.rx.nb_read()
+    }
+
     pub fn blocking_read(&mut self, buffer: &mut [u8]) -> Result<(), Error> {
         self.rx.blocking_read(buffer)
     }
@@ -281,27 +309,7 @@ mod eh02 {
     impl<'d, T: BasicInstance, RxDma> embedded_hal_02::serial::Read<u8> for UartRx<'d, T, RxDma> {
         type Error = Error;
         fn read(&mut self) -> Result<u8, nb::Error<Self::Error>> {
-            let r = T::regs();
-            unsafe {
-                let sr = sr(r).read();
-                if sr.pe() {
-                    rdr(r).read_volatile();
-                    Err(nb::Error::Other(Error::Parity))
-                } else if sr.fe() {
-                    rdr(r).read_volatile();
-                    Err(nb::Error::Other(Error::Framing))
-                } else if sr.ne() {
-                    rdr(r).read_volatile();
-                    Err(nb::Error::Other(Error::Noise))
-                } else if sr.ore() {
-                    rdr(r).read_volatile();
-                    Err(nb::Error::Other(Error::Overrun))
-                } else if sr.rxne() {
-                    Ok(rdr(r).read_volatile())
-                } else {
-                    Err(nb::Error::WouldBlock)
-                }
-            }
+            self.nb_read()
         }
     }
 
@@ -318,7 +326,7 @@ mod eh02 {
     impl<'d, T: BasicInstance, TxDma, RxDma> embedded_hal_02::serial::Read<u8> for Uart<'d, T, TxDma, RxDma> {
         type Error = Error;
         fn read(&mut self) -> Result<u8, nb::Error<Self::Error>> {
-            embedded_hal_02::serial::Read::read(&mut self.rx)
+            self.nb_read()
         }
     }
 
@@ -359,6 +367,58 @@ mod eh1 {
     impl<'d, T: BasicInstance, RxDma> embedded_hal_1::serial::ErrorType for UartRx<'d, T, RxDma> {
         type Error = Error;
     }
+
+    impl<'d, T: BasicInstance, RxDma> embedded_hal_nb::serial::Read for UartRx<'d, T, RxDma> {
+        fn read(&mut self) -> nb::Result<u8, Self::Error> {
+            self.nb_read()
+        }
+    }
+
+    impl<'d, T: BasicInstance, TxDma> embedded_hal_1::serial::Write for UartTx<'d, T, TxDma> {
+        fn write(&mut self, buffer: &[u8]) -> Result<(), Self::Error> {
+            self.blocking_write(buffer)
+        }
+
+        fn flush(&mut self) -> Result<(), Self::Error> {
+            self.blocking_flush()
+        }
+    }
+
+    impl<'d, T: BasicInstance, TxDma> embedded_hal_nb::serial::Write for UartTx<'d, T, TxDma> {
+        fn write(&mut self, char: u8) -> nb::Result<(), Self::Error> {
+            self.blocking_write(&[char]).map_err(nb::Error::Other)
+        }
+
+        fn flush(&mut self) -> nb::Result<(), Self::Error> {
+            self.blocking_flush().map_err(nb::Error::Other)
+        }
+    }
+
+    impl<'d, T: BasicInstance, TxDma, RxDma> embedded_hal_nb::serial::Read for Uart<'d, T, TxDma, RxDma> {
+        fn read(&mut self) -> Result<u8, nb::Error<Self::Error>> {
+            self.nb_read()
+        }
+    }
+
+    impl<'d, T: BasicInstance, TxDma, RxDma> embedded_hal_1::serial::Write for Uart<'d, T, TxDma, RxDma> {
+        fn write(&mut self, buffer: &[u8]) -> Result<(), Self::Error> {
+            self.blocking_write(buffer)
+        }
+
+        fn flush(&mut self) -> Result<(), Self::Error> {
+            self.blocking_flush()
+        }
+    }
+
+    impl<'d, T: BasicInstance, TxDma, RxDma> embedded_hal_nb::serial::Write for Uart<'d, T, TxDma, RxDma> {
+        fn write(&mut self, char: u8) -> nb::Result<(), Self::Error> {
+            self.blocking_write(&[char]).map_err(nb::Error::Other)
+        }
+
+        fn flush(&mut self) -> nb::Result<(), Self::Error> {
+            self.blocking_flush().map_err(nb::Error::Other)
+        }
+    }
 }
 
 #[cfg(all(