embassy/embassy-stm32/src/can.rs
2021-03-26 19:34:52 -05:00

121 lines
3.2 KiB
Rust

//! 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 nb;
use nb::block;
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);
// Infallible
self.can.transmit(frame).unwrap();
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>;
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 = "stm32f401",
feature = "stm32f405",
feature = "stm32f407",
feature = "stm32f410",
feature = "stm32f411",
feature = "stm32f412",
feature = "stm32f413",
feature = "stm32f415",
feature = "stm32f417",
feature = "stm32f423",
feature = "stm32f427",
feature = "stm32f429",
feature = "stm32f437",
feature = "stm32f439",
feature = "stm32f446",
feature = "stm32f469",
feature = "stm32f479",
))]
can! {
CAN1 => (CAN1_TX, CAN1_RX0),
CAN2 => (CAN2_TX, CAN2_RX0),
}