Merge pull request #20 from xoviat/canbus

add can

embassy-stm32f4/Cargo.toml

@@ -38,4 +38,6 @@ cortex-m-rt = "0.6.13"
 cortex-m = "0.7.1"
 embedded-hal    = { version = "0.2.4" }
 embedded-dma    = { version = "0.1.2" }
-stm32f4xx-hal  = { version = "0.8.3", features = ["rt"], git = "https://github.com/stm32-rs/stm32f4xx-hal.git"}
+stm32f4xx-hal  = { version = "0.8.3", features = ["rt", "can"], git = "https://github.com/stm32-rs/stm32f4xx-hal.git"}
+bxcan = "0.5.0"
+nb = "*"

embassy-stm32f4/src/can.rs

@@ -0,0 +1,103 @@
+//! Async low power Serial.
+//!
+//! The peripheral is autmatically enabled and disabled as required to save power.
+//! Lowest power consumption can only be guaranteed if the send receive futures
+//! are dropped correctly (e.g. not using `mem::forget()`).
+
+use bxcan;
+use bxcan::Interrupts;
+use core::future::Future;
+use embassy::interrupt::Interrupt;
+use embassy::util::InterruptFuture;
+use embassy::util::Signal;
+use nb;
+use nb::block;
+
+use crate::hal::prelude::*;
+use crate::interrupt;
+
+/// Interface to the Serial peripheral
+pub struct Can<T: Instance> {
+    can: bxcan::Can<T>,
+    tx_int: T::TInterrupt,
+    rx_int: T::RInterrupt,
+}
+
+impl<T: Instance> Can<T> {
+    pub fn new(mut can: bxcan::Can<T>, tx_int: T::TInterrupt, rx_int: T::RInterrupt) -> Self {
+        // Sync to the bus and start normal operation.
+        can.enable_interrupts(
+            Interrupts::TRANSMIT_MAILBOX_EMPTY | Interrupts::FIFO0_MESSAGE_PENDING,
+        );
+        block!(can.enable()).unwrap();
+
+        Can {
+            can: can,
+            tx_int: tx_int,
+            rx_int: rx_int,
+        }
+    }
+
+    /// Sends can frame.
+    ///
+    /// This method async-blocks until the frame is transmitted.
+    pub fn transmit<'a>(&'a mut self, frame: &'a bxcan::Frame) -> impl Future<Output = ()> + 'a {
+        async move {
+            let fut = InterruptFuture::new(&mut self.tx_int);
+            self.can.transmit(frame);
+
+            fut.await;
+        }
+    }
+
+    /// Receive can frame.
+    ///
+    /// This method async-blocks until the frame is received.
+    pub fn receive<'a>(&'a mut self) -> impl Future<Output = (bxcan::Frame)> + 'a {
+        async move {
+            let mut frame: Option<bxcan::Frame> = None;
+
+            loop {
+                let fut = InterruptFuture::new(&mut self.rx_int);
+                frame = match self.can.receive() {
+                    Ok(frame) => Some(frame),
+                    Err(nb::Error::WouldBlock) => None,
+                    Err(nb::Error::Other(_)) => None, // Ignore overrun errors.
+                };
+                if frame.is_some() {
+                    break;
+                }
+                fut.await;
+            }
+
+            frame.unwrap()
+        }
+    }
+}
+
+mod private {
+    pub trait Sealed {}
+}
+
+pub trait Instance: bxcan::Instance + private::Sealed {
+    type TInterrupt: Interrupt;
+    type RInterrupt: Interrupt;
+}
+
+macro_rules! can {
+    ($($can:ident => ($tint:ident, $rint:ident),)+) => {
+        $(
+            impl private::Sealed for crate::hal::can::Can<crate::pac::$can> {}
+            impl Instance for crate::hal::can::Can<crate::pac::$can> {
+                type TInterrupt = interrupt::$tint;
+                type RInterrupt = interrupt::$rint;
+            }
+        )+
+    }
+}
+
+#[cfg(any(feature = "stm32f405",))]
+can! {
+    CAN1 => (CAN1_TX, CAN1_RX0),
+    CAN2 => (CAN2_TX, CAN2_RX0),
+}

embassy-stm32f4/src/lib.rs

@@ -313,6 +313,7 @@ pub use stm32f4xx_hal::stm32 as pac;
 // This mod MUST go first, so that the others see its macros.
 pub(crate) mod fmt;
 
+pub mod can;
 pub mod exti;
 pub mod interrupt;
 pub mod qei;