completed async RX support as well

examples/embassy/Cargo.toml

@@ -9,7 +9,10 @@ cortex-m = { version = "0.7", features = ["critical-section-single-core"] }
 cortex-m-rt = "0.7"
 embedded-hal = "1"
 embedded-hal-async = "1"
+embedded-io = "0.6"
 embedded-io-async = "0.6"
+heapless = "0.8"
+static_cell = "2"
 
 rtt-target = "0.6"
 panic-rtt-target = "0.2"

examples/embassy/src/bin/async-uart-rx.rs

@@ -0,0 +1,171 @@
+//! Asynchronous UART reception example application.
+//!
+//! This application receives data on two UARTs permanently using a ring buffer.
+//! The ring buffer are read them asynchronously. UART A is received on ports PA8 and PA9.
+//! UART B is received on ports PA2 and PA3.
+//!
+//! Instructions:
+//!
+//! 1. Tie a USB to UART converter with RX to PA9 and TX to PA8 for UART A.
+//!    Tie a USB to UART converter with RX to PA3 and TX to PA2 for UART B.
+//! 2. Connect to the serial interface by using an application like Putty or picocom. You can
+//!    type something in the terminal and check if the data is echoed back. You can also check the
+//!    RTT logs to see received data.
+#![no_std]
+#![no_main]
+use core::cell::RefCell;
+
+use critical_section::Mutex;
+use embassy_executor::Spawner;
+use embassy_time::Instant;
+use embedded_hal::digital::StatefulOutputPin;
+use embedded_io::Write;
+use embedded_io_async::Read;
+use heapless::spsc::{Consumer, Producer, Queue};
+use panic_rtt_target as _;
+use rtt_target::{rprintln, rtt_init_print};
+use va108xx_embassy::embassy;
+use va108xx_hal::{
+    gpio::PinsA,
+    pac::{self, interrupt},
+    prelude::*,
+    uart::{
+        self, on_interrupt_uart_b_overwriting,
+        rx_asynch::{on_interrupt_uart_a, RxAsync},
+        RxAsyncSharedConsumer, Tx,
+    },
+    InterruptConfig,
+};
+
+const SYSCLK_FREQ: Hertz = Hertz::from_raw(50_000_000);
+
+static QUEUE_UART_A: static_cell::ConstStaticCell<Queue<u8, 256>> =
+    static_cell::ConstStaticCell::new(Queue::new());
+static PRODUCER_UART_A: Mutex<RefCell<Option<Producer<u8, 256>>>> = Mutex::new(RefCell::new(None));
+
+static QUEUE_UART_B: static_cell::ConstStaticCell<Queue<u8, 256>> =
+    static_cell::ConstStaticCell::new(Queue::new());
+static PRODUCER_UART_B: Mutex<RefCell<Option<Producer<u8, 256>>>> = Mutex::new(RefCell::new(None));
+static CONSUMER_UART_B: Mutex<RefCell<Option<Consumer<u8, 256>>>> = Mutex::new(RefCell::new(None));
+
+// main is itself an async function.
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    rtt_init_print!();
+    rprintln!("-- VA108xx Async UART RX Demo --");
+
+    let mut dp = pac::Peripherals::take().unwrap();
+
+    // Safety: Only called once here.
+    unsafe {
+        embassy::init(
+            &mut dp.sysconfig,
+            &dp.irqsel,
+            SYSCLK_FREQ,
+            dp.tim23,
+            dp.tim22,
+        );
+    }
+
+    let porta = PinsA::new(&mut dp.sysconfig, dp.porta);
+    let mut led0 = porta.pa10.into_readable_push_pull_output();
+    let mut led1 = porta.pa7.into_readable_push_pull_output();
+    let mut led2 = porta.pa6.into_readable_push_pull_output();
+
+    let tx_uart_a = porta.pa9.into_funsel_2();
+    let rx_uart_a = porta.pa8.into_funsel_2();
+
+    let uarta = uart::Uart::new_with_interrupt(
+        &mut dp.sysconfig,
+        50.MHz(),
+        dp.uarta,
+        (tx_uart_a, rx_uart_a),
+        115200.Hz(),
+        InterruptConfig::new(pac::Interrupt::OC2, true, true),
+    );
+
+    let tx_uart_b = porta.pa3.into_funsel_2();
+    let rx_uart_b = porta.pa2.into_funsel_2();
+
+    let uartb = uart::Uart::new_with_interrupt(
+        &mut dp.sysconfig,
+        50.MHz(),
+        dp.uartb,
+        (tx_uart_b, rx_uart_b),
+        115200.Hz(),
+        InterruptConfig::new(pac::Interrupt::OC3, true, true),
+    );
+    let (mut tx_uart_a, rx_uart_a) = uarta.split();
+    let (tx_uart_b, rx_uart_b) = uartb.split();
+    let (prod_uart_a, cons_uart_a) = QUEUE_UART_A.take().split();
+    // Pass the producer to the interrupt handler.
+    let (prod_uart_b, cons_uart_b) = QUEUE_UART_B.take().split();
+    critical_section::with(|cs| {
+        *PRODUCER_UART_A.borrow(cs).borrow_mut() = Some(prod_uart_a);
+        *PRODUCER_UART_B.borrow(cs).borrow_mut() = Some(prod_uart_b);
+        *CONSUMER_UART_B.borrow(cs).borrow_mut() = Some(cons_uart_b);
+    });
+    let mut async_rx_uart_a = RxAsync::new(rx_uart_a, cons_uart_a);
+    let async_rx_uart_b = RxAsyncSharedConsumer::new(rx_uart_b, &CONSUMER_UART_B);
+    spawner
+        .spawn(uart_b_task(async_rx_uart_b, tx_uart_b))
+        .unwrap();
+    let mut buf = [0u8; 256];
+    loop {
+        rprintln!("Current time UART A: {}", Instant::now().as_secs());
+        led0.toggle().ok();
+        led1.toggle().ok();
+        led2.toggle().ok();
+        let read_bytes = async_rx_uart_a.read(&mut buf).await.unwrap();
+        let read_str = core::str::from_utf8(&buf[..read_bytes]).unwrap();
+        rprintln!(
+            "Read {} bytes asynchronously on UART A: {:?}",
+            read_bytes,
+            read_str
+        );
+        tx_uart_a.write_all(read_str.as_bytes()).unwrap();
+    }
+}
+
+#[embassy_executor::task]
+async fn uart_b_task(mut async_rx: RxAsyncSharedConsumer<pac::Uartb, 256>, mut tx: Tx<pac::Uartb>) {
+    let mut buf = [0u8; 256];
+    loop {
+        rprintln!("Current time UART B: {}", Instant::now().as_secs());
+        // Infallible asynchronous operation.
+        let read_bytes = async_rx.read(&mut buf).await.unwrap();
+        let read_str = core::str::from_utf8(&buf[..read_bytes]).unwrap();
+        rprintln!(
+            "Read {} bytes asynchronously on UART B: {:?}",
+            read_bytes,
+            read_str
+        );
+        tx.write_all(read_str.as_bytes()).unwrap();
+    }
+}
+
+#[interrupt]
+#[allow(non_snake_case)]
+fn OC2() {
+    let mut prod =
+        critical_section::with(|cs| PRODUCER_UART_A.borrow(cs).borrow_mut().take().unwrap());
+    let errors = on_interrupt_uart_a(&mut prod);
+    critical_section::with(|cs| *PRODUCER_UART_A.borrow(cs).borrow_mut() = Some(prod));
+    // In a production app, we could use a channel to send the errors to the main task.
+    if let Err(errors) = errors {
+        rprintln!("UART A errors: {:?}", errors);
+    }
+}
+
+#[interrupt]
+#[allow(non_snake_case)]
+fn OC3() {
+    let mut prod =
+        critical_section::with(|cs| PRODUCER_UART_B.borrow(cs).borrow_mut().take().unwrap());
+    let errors = on_interrupt_uart_b_overwriting(&mut prod, &CONSUMER_UART_B);
+    critical_section::with(|cs| *PRODUCER_UART_B.borrow(cs).borrow_mut() = Some(prod));
+    // In a production app, we could use a channel to send the errors to the main task.
+    if let Err(errors) = errors {
+        rprintln!("UART B errors: {:?}", errors);
+    }
+}

examples/embassy/src/bin/async-uart-tx.rs

@@ -1,3 +1,13 @@
+//! Asynchronous UART transmission example application.
+//!
+//! This application receives sends 4 strings with different sizes permanently using UART A.
+//! Ports PA8 and PA9 are used for this.
+//!
+//! Instructions:
+//!
+//! 1. Tie a USB to UART converter with RX to PA9 and TX to PA8 for UART A.
+//! 2. Connect to the serial interface by using an application like Putty or picocom. You can
+//!    can verify the correctness of the sent strings.
 #![no_std]
 #![no_main]
 use embassy_executor::Spawner;
@@ -28,7 +38,7 @@ const STR_LIST: &[&str] = &[
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
     rtt_init_print!();
-    rprintln!("-- VA108xx Embassy Demo --");
+    rprintln!("-- VA108xx Async UART TX Demo --");
 
     let mut dp = pac::Peripherals::take().unwrap();
 

examples/simple/examples/uart.rs

@@ -27,15 +27,15 @@ fn main() -> ! {
     let gpioa = PinsA::new(&mut dp.sysconfig, dp.porta);
     let tx = gpioa.pa9.into_funsel_2();
     let rx = gpioa.pa8.into_funsel_2();
-
-    let uarta = uart::Uart::new_without_interrupt(
+    let uart = uart::Uart::new_without_interrupt(
         &mut dp.sysconfig,
         50.MHz(),
         dp.uarta,
         (tx, rx),
         115200.Hz(),
     );
-    let (mut tx, mut rx) = uarta.split();
+
+    let (mut tx, mut rx) = uart.split();
     writeln!(tx, "Hello World\r").unwrap();
     loop {
         // Echo what is received on the serial link.