Merge #514

514: Serial Tx, Rx containing pins r=therealprof a=burrbull

Related to #505 

Instead of changing API I added alternative.

So now to can choose between `Tx`, `Rx` with erased information about pins and `UTx`, `URx` which can join to restore `Serial`

Co-authored-by: Andrey Zgarbul <zgarbul.andrey@gmail.com>

Author: bors[bot]

CHANGELOG.md

@@ -25,6 +25,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Added
 
+- Serial Tx, Rx containing pins [#514]
 - Implementation of From trait for Pin-to-PartiallyErasedPin [#507]
 - Implementation of From trait for Pin-to-ErasedPin [#507]
 - Implementation of From trait for PartiallyErasedPin-to-ErasedPin [#507]
@@ -38,6 +39,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 [#507]: https://github.com/stm32-rs/stm32f4xx-hal/pull/507
 [#508]: https://github.com/stm32-rs/stm32f4xx-hal/pull/508
 [#510]: https://github.com/stm32-rs/stm32f4xx-hal/pull/510
+[#510]: https://github.com/stm32-rs/stm32f4xx-hal/pull/514
 
 ## [v0.13.2] - 2022-05-16
 

src/serial.rs

@@ -332,6 +332,123 @@ impl<USART, PINS, WORD> AsMut<Rx<USART, WORD>> for Serial<USART, PINS, WORD> {
     }
 }
 
+/// Serial receiver containing RX pin
+pub struct URx<USART, RX, WORD = u8> {
+    _usart: PhantomData<USART>,
+    pin: RX,
+    _word: PhantomData<WORD>,
+}
+
+/// Serial transmitter containing TX pin
+pub struct UTx<USART, TX, WORD = u8> {
+    usart: USART,
+    pin: TX,
+    _word: PhantomData<WORD>,
+}
+
+impl<USART: Instance, RX, WORD> URx<USART, RX, WORD> {
+    fn new(pin: RX) -> Self {
+        Self {
+            _usart: PhantomData,
+            pin,
+            _word: PhantomData,
+        }
+    }
+
+    pub fn erase(self) -> Rx<USART, WORD> {
+        Rx::new()
+    }
+
+    /// Start listening for an rx not empty interrupt event
+    ///
+    /// Note, you will also have to enable the corresponding interrupt
+    /// in the NVIC to start receiving events.
+    pub fn listen(&mut self) {
+        unsafe { (*USART::ptr()).cr1.modify(|_, w| w.rxneie().set_bit()) }
+    }
+
+    /// Stop listening for the rx not empty interrupt event
+    pub fn unlisten(&mut self) {
+        unsafe { (*USART::ptr()).cr1.modify(|_, w| w.rxneie().clear_bit()) }
+    }
+
+    /// Start listening for a line idle interrupt event
+    ///
+    /// Note, you will also have to enable the corresponding interrupt
+    /// in the NVIC to start receiving events.
+    pub fn listen_idle(&mut self) {
+        unsafe { (*USART::ptr()).cr1.modify(|_, w| w.idleie().set_bit()) }
+    }
+
+    /// Stop listening for the line idle interrupt event
+    pub fn unlisten_idle(&mut self) {
+        unsafe { (*USART::ptr()).cr1.modify(|_, w| w.idleie().clear_bit()) }
+    }
+
+    /// Return true if the line idle status is set
+    pub fn is_idle(&self) -> bool {
+        unsafe { (*USART::ptr()).sr.read().idle().bit_is_set() }
+    }
+
+    /// Return true if the rx register is not empty (and can be read)
+    pub fn is_rx_not_empty(&self) -> bool {
+        unsafe { (*USART::ptr()).sr.read().rxne().bit_is_set() }
+    }
+
+    /// Clear idle line interrupt flag
+    pub fn clear_idle_interrupt(&self) {
+        unsafe {
+            let _ = (*USART::ptr()).sr.read();
+            let _ = (*USART::ptr()).dr.read();
+        }
+    }
+}
+
+impl<USART: Instance, TX, WORD> UTx<USART, TX, WORD> {
+    fn new(usart: USART, pin: TX) -> Self {
+        Self {
+            usart,
+            pin,
+            _word: PhantomData,
+        }
+    }
+
+    pub fn erase(self) -> Tx<USART, WORD> {
+        Tx::new()
+    }
+
+    pub fn join<RX>(self, rx: URx<USART, RX, WORD>) -> Serial<USART, (TX, RX), WORD>
+    where
+        (TX, RX): Pins<USART>,
+    {
+        Serial {
+            usart: self.usart,
+            pins: (self.pin, rx.pin),
+            tx: Tx::new(),
+            rx: Rx::new(),
+        }
+    }
+
+    /// Start listening for a tx empty interrupt event
+    ///
+    /// Note, you will also have to enable the corresponding interrupt
+    /// in the NVIC to start receiving events.
+    // TODO: replace with "self.usart"
+    pub fn listen(&mut self) {
+        unsafe { (*USART::ptr()).cr1.modify(|_, w| w.txeie().set_bit()) }
+    }
+
+    /// Stop listening for the tx empty interrupt event
+    pub fn unlisten(&mut self) {
+        unsafe { (*USART::ptr()).cr1.modify(|_, w| w.txeie().clear_bit()) }
+    }
+
+    /// Return true if the tx register is empty (and can accept data)
+    pub fn is_tx_empty(&self) -> bool {
+        unsafe { (*USART::ptr()).sr.read().txe().bit_is_set() }
+    }
+}
+
 pub trait SerialExt: Sized + Instance {
     fn serial<TX, RX, WORD>(
         self,
@@ -614,6 +731,12 @@ impl<USART: Instance, PINS, WORD> Serial<USART, PINS, WORD> {
     }
 }
 
+impl<USART: Instance, TX, RX, WORD> Serial<USART, (TX, RX), WORD> {
+    pub fn split_nondestructive(self) -> (UTx<USART, TX, WORD>, URx<USART, RX, WORD>) {
+        (UTx::new(self.usart, self.pins.0), URx::new(self.pins.1))
+    }
+}
+
 impl<USART: Instance, PINS> Serial<USART, PINS, u8> {
     /// Converts this Serial into a version that can read and write `u16` values instead of `u8`s
     ///
@@ -912,3 +1035,109 @@ impl<USART: Instance> Tx<USART, u16> {
         nb::block!(self.flush())
     }
 }
+
+impl<USART: Instance, TX> fmt::Write for UTx<USART, TX> {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        s.bytes()
+            .try_for_each(|c| block!(self.write(c)))
+            .map_err(|_| fmt::Error)
+    }
+}
+
+impl<USART: Instance, RX> URx<USART, RX, u8> {
+    fn read(&mut self) -> nb::Result<u8, Error> {
+        // Delegate to the Read<u16> implementation, then truncate to 8 bits
+        Rx::<USART, u16>::new().read().map(|word16| word16 as u8)
+    }
+}
+
+impl<USART: Instance, RX> URx<USART, RX, u16> {
+    fn read(&mut self) -> nb::Result<u16, Error> {
+        // NOTE(unsafe) atomic read with no side effects
+        let sr = unsafe { (*USART::ptr()).sr.read() };
+
+        // Any error requires the dr to be read to clear
+        if sr.pe().bit_is_set()
+            || sr.fe().bit_is_set()
+            || sr.nf().bit_is_set()
+            || sr.ore().bit_is_set()
+        {
+            unsafe { (*USART::ptr()).dr.read() };
+        }
+
+        Err(if sr.pe().bit_is_set() {
+            Error::Parity.into()
+        } else if sr.fe().bit_is_set() {
+            Error::FrameFormat.into()
+        } else if sr.nf().bit_is_set() {
+            Error::Noise.into()
+        } else if sr.ore().bit_is_set() {
+            Error::Overrun.into()
+        } else if sr.rxne().bit_is_set() {
+            // NOTE(unsafe) atomic read from stateless register
+            return Ok(unsafe { &*USART::ptr() }.dr.read().dr().bits());
+        } else {
+            nb::Error::WouldBlock
+        })
+    }
+}
+
+impl<USART: Instance, TX> UTx<USART, TX, u8> {
+    fn write(&mut self, word: u8) -> nb::Result<(), Error> {
+        // Delegate to u16 version
+        Tx::<USART, u16>::new().write(u16::from(word))
+    }
+
+    fn flush(&mut self) -> nb::Result<(), Error> {
+        // Delegate to u16 version
+        Tx::<USART, u16>::new().flush()
+    }
+
+    fn bwrite_all(&mut self, bytes: &[u8]) -> Result<(), Error> {
+        for &b in bytes {
+            nb::block!(self.write(b))?;
+        }
+        Ok(())
+    }
+
+    fn bflush(&mut self) -> Result<(), Error> {
+        nb::block!(self.flush())
+    }
+}
+
+impl<USART: Instance, TX> UTx<USART, TX, u16> {
+    fn write(&mut self, word: u16) -> nb::Result<(), Error> {
+        // NOTE(unsafe) atomic read with no side effects
+        let sr = unsafe { (*USART::ptr()).sr.read() };
+
+        if sr.txe().bit_is_set() {
+            // NOTE(unsafe) atomic write to stateless register
+            unsafe { &*USART::ptr() }.dr.write(|w| w.dr().bits(word));
+            Ok(())
+        } else {
+            Err(nb::Error::WouldBlock)
+        }
+    }
+
+    fn flush(&mut self) -> nb::Result<(), Error> {
+        // NOTE(unsafe) atomic read with no side effects
+        let sr = unsafe { (*USART::ptr()).sr.read() };
+
+        if sr.tc().bit_is_set() {
+            Ok(())
+        } else {
+            Err(nb::Error::WouldBlock)
+        }
+    }
+
+    fn bwrite_all(&mut self, buffer: &[u16]) -> Result<(), Error> {
+        for &b in buffer {
+            nb::block!(self.write(b))?;
+        }
+        Ok(())
+    }
+
+    fn bflush(&mut self) -> Result<(), Error> {
+        nb::block!(self.flush())
+    }
+}

src/serial/hal_02.rs

@@ -1,5 +1,5 @@
 mod nb {
-    use super::super::{Error, Instance, Rx, Serial, Tx};
+    use super::super::{Error, Instance, Rx, Serial, Tx, URx, UTx};
     use embedded_hal::serial::{Read, Write};
 
     impl<USART, PINS, WORD> Read<WORD> for Serial<USART, PINS, WORD>
@@ -22,6 +22,14 @@ mod nb {
         }
     }
 
+    impl<USART: Instance, RX> Read<u8> for URx<USART, RX, u8> {
+        type Error = Error;
+
+        fn read(&mut self) -> nb::Result<u8, Self::Error> {
+            self.read()
+        }
+    }
+
     /// Reads 9-bit words from the UART/USART
     ///
     /// If the UART/USART was configured with `WordLength::DataBits9`, the returned value will contain
@@ -35,6 +43,14 @@ mod nb {
         }
     }
 
+    impl<USART: Instance, RX> Read<u16> for URx<USART, RX, u16> {
+        type Error = Error;
+
+        fn read(&mut self) -> nb::Result<u16, Self::Error> {
+            self.read()
+        }
+    }
+
     impl<USART, PINS, WORD> Write<WORD> for Serial<USART, PINS, WORD>
     where
         USART: Instance,
@@ -51,7 +67,7 @@ mod nb {
         }
     }
 
-    impl<USART: Instance> Write<u8> for Tx<USART, u8> {
+    impl<USART: Instance, TX> Write<u8> for UTx<USART, TX, u8> {
         type Error = Error;
 
         fn write(&mut self, word: u8) -> nb::Result<(), Self::Error> {
@@ -79,10 +95,22 @@ mod nb {
             self.flush()
         }
     }
+
+    impl<USART: Instance, TX> Write<u16> for UTx<USART, TX, u16> {
+        type Error = Error;
+
+        fn write(&mut self, word: u16) -> nb::Result<(), Self::Error> {
+            self.write(word)
+        }
+
+        fn flush(&mut self) -> nb::Result<(), Self::Error> {
+            self.flush()
+        }
+    }
 }
 
 mod blocking {
-    use super::super::{Error, Instance, Serial, Tx};
+    use super::super::{Error, Instance, Serial, Tx, UTx};
     use embedded_hal::blocking::serial::Write;
 
     impl<USART: Instance> Write<u8> for Tx<USART, u8> {
@@ -97,6 +125,18 @@ mod blocking {
         }
     }
 
+    impl<USART: Instance, TX> Write<u8> for UTx<USART, TX, u8> {
+        type Error = Error;
+
+        fn bwrite_all(&mut self, bytes: &[u8]) -> Result<(), Self::Error> {
+            self.bwrite_all(bytes)
+        }
+
+        fn bflush(&mut self) -> Result<(), Self::Error> {
+            self.bflush()
+        }
+    }
+
     impl<USART: Instance, PINS> Write<u8> for Serial<USART, PINS, u8> {
         type Error = Error;
 
@@ -121,6 +161,18 @@ mod blocking {
         }
     }
 
+    impl<USART: Instance, TX> Write<u16> for UTx<USART, TX, u16> {
+        type Error = Error;
+
+        fn bwrite_all(&mut self, slice: &[u16]) -> Result<(), Self::Error> {
+            self.bwrite_all(slice)
+        }
+
+        fn bflush(&mut self) -> Result<(), Self::Error> {
+            self.bflush()
+        }
+    }
+
     impl<USART: Instance, PINS> Write<u16> for Serial<USART, PINS, u16> {
         type Error = Error;