stm32: add support for STM32H7[RS] "bootflash line", add HIL tests.

examples/stm32h7rs/.cargo/config.toml

@@ -0,0 +1,8 @@
+[target.thumbv7em-none-eabihf]
+runner = 'probe-rs run --chip STM32H7S3L8Hx'
+
+[build]
+target = "thumbv7em-none-eabihf" # Cortex-M4F and Cortex-M7F (with FPU)
+
+[env]
+DEFMT_LOG = "trace"

examples/stm32h7rs/Cargo.toml

@@ -0,0 +1,73 @@
+[package]
+edition = "2021"
+name = "embassy-stm32h7-examples"
+version = "0.1.0"
+license = "MIT OR Apache-2.0"
+
+[dependencies]
+# Change stm32h743bi to your chip name, if necessary.
+embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["defmt", "stm32h7s3l8", "time-driver-tim2", "exti", "memory-x", "unstable-pac", "chrono"] }
+embassy-sync = { version = "0.5.0", path = "../../embassy-sync", features = ["defmt"] }
+embassy-executor = { version = "0.5.0", path = "../../embassy-executor", features = ["task-arena-size-32768", "arch-cortex-m", "executor-thread", "executor-interrupt", "defmt", "integrated-timers"] }
+embassy-time = { version = "0.3.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-hz-32_768"] }
+embassy-net = { version = "0.4.0", path = "../../embassy-net", features = ["defmt", "tcp", "dhcpv4", "medium-ethernet", "proto-ipv6", "dns"] }
+embassy-usb = { version = "0.2.0", path = "../../embassy-usb", features = ["defmt"] }
+embassy-futures = { version = "0.1.0", path = "../../embassy-futures" }
+
+defmt = "0.3"
+defmt-rtt = "0.4"
+
+cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-single-core"] }
+cortex-m-rt = "0.7.0"
+embedded-hal = "0.2.6"
+embedded-hal-1 = { package = "embedded-hal", version = "1.0" }
+embedded-hal-async = { version = "1.0" }
+embedded-nal-async = { version = "0.7.1" }
+embedded-io-async = { version = "0.6.1" }
+panic-probe = { version = "0.3", features = ["print-defmt"] }
+heapless = { version = "0.8", default-features = false }
+rand_core = "0.6.3"
+critical-section = "1.1"
+micromath = "2.0.0"
+stm32-fmc = "0.3.0"
+embedded-storage = "0.3.1"
+static_cell = "2"
+chrono = { version = "^0.4", default-features = false }
+
+# cargo build/run
+[profile.dev]
+codegen-units = 1
+debug = 2
+debug-assertions = true # <-
+incremental = false
+opt-level = 3 # <-
+overflow-checks = true # <-
+
+# cargo test
+[profile.test]
+codegen-units = 1
+debug = 2
+debug-assertions = true # <-
+incremental = false
+opt-level = 3 # <-
+overflow-checks = true # <-
+
+# cargo build/run --release
+[profile.release]
+codegen-units = 1
+debug = 2
+debug-assertions = false # <-
+incremental = false
+lto = 'fat'
+opt-level = 3 # <-
+overflow-checks = false # <-
+
+# cargo test --release
+[profile.bench]
+codegen-units = 1
+debug = 2
+debug-assertions = false # <-
+incremental = false
+lto = 'fat'
+opt-level = 3 # <-
+overflow-checks = false # <-

examples/stm32h7rs/build.rs

@@ -0,0 +1,5 @@
+fn main() {
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}

examples/stm32h7rs/src/bin/blinky.rs

@@ -0,0 +1,51 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_stm32::time::Hertz;
+use embassy_stm32::Config;
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = Config::default();
+    {
+        use embassy_stm32::rcc::*;
+        config.rcc.hse = Some(Hse {
+            freq: Hertz(24_000_000),
+            mode: HseMode::Oscillator,
+        });
+        config.rcc.pll1 = Some(Pll {
+            source: PllSource::HSE,
+            prediv: PllPreDiv::DIV3,
+            mul: PllMul::MUL150,
+            divp: Some(PllDiv::DIV2),
+            divq: None,
+            divr: None,
+        });
+        config.rcc.sys = Sysclk::PLL1_P; // 600 Mhz
+        config.rcc.ahb_pre = AHBPrescaler::DIV2; // 300 Mhz
+        config.rcc.apb1_pre = APBPrescaler::DIV2; // 150 Mhz
+        config.rcc.apb2_pre = APBPrescaler::DIV2; // 150 Mhz
+        config.rcc.apb4_pre = APBPrescaler::DIV2; // 150 Mhz
+        config.rcc.apb5_pre = APBPrescaler::DIV2; // 150 Mhz
+        config.rcc.voltage_scale = VoltageScale::HIGH;
+    }
+    let p = embassy_stm32::init(config);
+    info!("Hello World!");
+
+    let mut led = Output::new(p.PD10, Level::High, Speed::Low);
+
+    loop {
+        info!("high");
+        led.set_high();
+        Timer::after_millis(500).await;
+
+        info!("low");
+        led.set_low();
+        Timer::after_millis(500).await;
+    }
+}

examples/stm32h7rs/src/bin/button_exti.rs

@@ -0,0 +1,25 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::exti::ExtiInput;
+use embassy_stm32::gpio::Pull;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let mut button = ExtiInput::new(p.PC13, p.EXTI13, Pull::Up);
+
+    info!("Press the USER button...");
+
+    loop {
+        button.wait_for_falling_edge().await;
+        info!("Pressed!");
+        button.wait_for_rising_edge().await;
+        info!("Released!");
+    }
+}

examples/stm32h7rs/src/bin/can.rs

@@ -0,0 +1,98 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::peripherals::*;
+use embassy_stm32::{bind_interrupts, can, rcc, Config};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    FDCAN1_IT0 => can::IT0InterruptHandler<FDCAN1>;
+    FDCAN1_IT1 => can::IT1InterruptHandler<FDCAN1>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = Config::default();
+    config.rcc.hse = Some(rcc::Hse {
+        freq: embassy_stm32::time::Hertz(25_000_000),
+        mode: rcc::HseMode::Oscillator,
+    });
+    config.rcc.mux.fdcansel = rcc::mux::Fdcansel::HSE;
+
+    let peripherals = embassy_stm32::init(config);
+
+    let mut can = can::CanConfigurator::new(peripherals.FDCAN1, peripherals.PA11, peripherals.PA12, Irqs);
+
+    // 250k bps
+    can.set_bitrate(250_000);
+
+    //let mut can = can.into_internal_loopback_mode();
+    let mut can = can.into_normal_mode();
+
+    info!("CAN Configured");
+
+    let mut i = 0;
+    let mut last_read_ts = embassy_time::Instant::now();
+
+    loop {
+        let frame = can::frame::Frame::new_extended(0x123456F, &[i; 8]).unwrap();
+        info!("Writing frame");
+        _ = can.write(&frame).await;
+
+        match can.read().await {
+            Ok(envelope) => {
+                let (rx_frame, ts) = envelope.parts();
+                let delta = (ts - last_read_ts).as_millis();
+                last_read_ts = ts;
+                info!(
+                    "Rx: {:x} {:x} {:x} {:x} --- NEW {}",
+                    rx_frame.data()[0],
+                    rx_frame.data()[1],
+                    rx_frame.data()[2],
+                    rx_frame.data()[3],
+                    delta,
+                )
+            }
+            Err(_err) => error!("Error in frame"),
+        }
+
+        Timer::after_millis(250).await;
+
+        i += 1;
+        if i > 3 {
+            break;
+        }
+    }
+
+    let (mut tx, mut rx, _props) = can.split();
+    // With split
+    loop {
+        let frame = can::frame::Frame::new_extended(0x123456F, &[i; 8]).unwrap();
+        info!("Writing frame");
+        _ = tx.write(&frame).await;
+
+        match rx.read().await {
+            Ok(envelope) => {
+                let (rx_frame, ts) = envelope.parts();
+                let delta = (ts - last_read_ts).as_millis();
+                last_read_ts = ts;
+                info!(
+                    "Rx: {:x} {:x} {:x} {:x} --- NEW {}",
+                    rx_frame.data()[0],
+                    rx_frame.data()[1],
+                    rx_frame.data()[2],
+                    rx_frame.data()[3],
+                    delta,
+                )
+            }
+            Err(_err) => error!("Error in frame"),
+        }
+
+        Timer::after_millis(250).await;
+
+        i = i.wrapping_add(1);
+    }
+}

examples/stm32h7rs/src/bin/mco.rs

@@ -0,0 +1,29 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::gpio::{Level, Output, Speed};
+use embassy_stm32::rcc::{Mco, Mco1Source, McoPrescaler};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let mut led = Output::new(p.PB14, Level::High, Speed::Low);
+
+    let _mco = Mco::new(p.MCO1, p.PA8, Mco1Source::HSI, McoPrescaler::DIV8);
+
+    loop {
+        info!("high");
+        led.set_high();
+        Timer::after_millis(500).await;
+
+        info!("low");
+        led.set_low();
+        Timer::after_millis(500).await;
+    }
+}

examples/stm32h7rs/src/bin/multiprio.rs

@@ -0,0 +1,150 @@
+//! This example showcases how to create multiple Executor instances to run tasks at
+//! different priority levels.
+//!
+//! Low priority executor runs in thread mode (not interrupt), and uses `sev` for signaling
+//! there's work in the queue, and `wfe` for waiting for work.
+//!
+//! Medium and high priority executors run in two interrupts with different priorities.
+//! Signaling work is done by pending the interrupt. No "waiting" needs to be done explicitly, since
+//! when there's work the interrupt will trigger and run the executor.
+//!
+//! Sample output below. Note that high priority ticks can interrupt everything else, and
+//! medium priority computations can interrupt low priority computations, making them to appear
+//! to take significantly longer time.
+//!
+//! ```not_rust
+//!     [med] Starting long computation
+//!     [med] done in 992 ms
+//!         [high] tick!
+//! [low] Starting long computation
+//!     [med] Starting long computation
+//!         [high] tick!
+//!         [high] tick!
+//!     [med] done in 993 ms
+//!     [med] Starting long computation
+//!         [high] tick!
+//!         [high] tick!
+//!     [med] done in 993 ms
+//! [low] done in 3972 ms
+//!     [med] Starting long computation
+//!         [high] tick!
+//!         [high] tick!
+//!     [med] done in 993 ms
+//! ```
+//!
+//! For comparison, try changing the code so all 3 tasks get spawned on the low priority executor.
+//! You will get an output like the following. Note that no computation is ever interrupted.
+//!
+//! ```not_rust
+//!         [high] tick!
+//!     [med] Starting long computation
+//!     [med] done in 496 ms
+//! [low] Starting long computation
+//! [low] done in 992 ms
+//!     [med] Starting long computation
+//!     [med] done in 496 ms
+//!         [high] tick!
+//! [low] Starting long computation
+//! [low] done in 992 ms
+//!         [high] tick!
+//!     [med] Starting long computation
+//!     [med] done in 496 ms
+//!         [high] tick!
+//! ```
+//!
+
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::{Executor, InterruptExecutor};
+use embassy_stm32::interrupt;
+use embassy_stm32::interrupt::{InterruptExt, Priority};
+use embassy_time::{Instant, Timer};
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn run_high() {
+    loop {
+        info!("        [high] tick!");
+        Timer::after_ticks(27374).await;
+    }
+}
+
+#[embassy_executor::task]
+async fn run_med() {
+    loop {
+        let start = Instant::now();
+        info!("    [med] Starting long computation");
+
+        // Spin-wait to simulate a long CPU computation
+        cortex_m::asm::delay(128_000_000); // ~1 second
+
+        let end = Instant::now();
+        let ms = end.duration_since(start).as_ticks() / 33;
+        info!("    [med] done in {} ms", ms);
+
+        Timer::after_ticks(23421).await;
+    }
+}
+
+#[embassy_executor::task]
+async fn run_low() {
+    loop {
+        let start = Instant::now();
+        info!("[low] Starting long computation");
+
+        // Spin-wait to simulate a long CPU computation
+        cortex_m::asm::delay(256_000_000); // ~2 seconds
+
+        let end = Instant::now();
+        let ms = end.duration_since(start).as_ticks() / 33;
+        info!("[low] done in {} ms", ms);
+
+        Timer::after_ticks(32983).await;
+    }
+}
+
+static EXECUTOR_HIGH: InterruptExecutor = InterruptExecutor::new();
+static EXECUTOR_MED: InterruptExecutor = InterruptExecutor::new();
+static EXECUTOR_LOW: StaticCell<Executor> = StaticCell::new();
+
+#[interrupt]
+unsafe fn UART4() {
+    EXECUTOR_HIGH.on_interrupt()
+}
+
+#[interrupt]
+unsafe fn UART5() {
+    EXECUTOR_MED.on_interrupt()
+}
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let _p = embassy_stm32::init(Default::default());
+
+    // STM32s don’t have any interrupts exclusively for software use, but they can all be triggered by software as well as
+    // by the peripheral, so we can just use any free interrupt vectors which aren’t used by the rest of your application.
+    // In this case we’re using UART4 and UART5, but there’s nothing special about them. Any otherwise unused interrupt
+    // vector would work exactly the same.
+
+    // High-priority executor: UART4, priority level 6
+    interrupt::UART4.set_priority(Priority::P6);
+    let spawner = EXECUTOR_HIGH.start(interrupt::UART4);
+    unwrap!(spawner.spawn(run_high()));
+
+    // Medium-priority executor: UART5, priority level 7
+    interrupt::UART5.set_priority(Priority::P7);
+    let spawner = EXECUTOR_MED.start(interrupt::UART5);
+    unwrap!(spawner.spawn(run_med()));
+
+    // Low priority executor: runs in thread mode, using WFE/SEV
+    let executor = EXECUTOR_LOW.init(Executor::new());
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(run_low()));
+    });
+}

examples/stm32h7rs/src/bin/rng.rs

@@ -0,0 +1,26 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::rng::Rng;
+use embassy_stm32::{bind_interrupts, peripherals, rng, Config};
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    RNG => rng::InterruptHandler<peripherals::RNG>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = Config::default();
+    config.rcc.hsi48 = Some(Default::default()); // needed for RNG
+    let p = embassy_stm32::init(config);
+    info!("Hello World!");
+
+    let mut rng = Rng::new(p.RNG, Irqs);
+
+    let mut buf = [0u8; 16];
+    unwrap!(rng.async_fill_bytes(&mut buf).await);
+    info!("random bytes: {:02x}", buf);
+}

examples/stm32h7rs/src/bin/rtc.rs

@@ -0,0 +1,36 @@
+#![no_std]
+#![no_main]
+
+use chrono::{NaiveDate, NaiveDateTime};
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::rcc::LsConfig;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
+use embassy_stm32::Config;
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = Config::default();
+    config.rcc.ls = LsConfig::default_lse();
+
+    let p = embassy_stm32::init(config);
+    info!("Hello World!");
+
+    let now = NaiveDate::from_ymd_opt(2020, 5, 15)
+        .unwrap()
+        .and_hms_opt(10, 30, 15)
+        .unwrap();
+
+    let mut rtc = Rtc::new(p.RTC, RtcConfig::default());
+    info!("Got RTC! {:?}", now.and_utc().timestamp());
+
+    rtc.set_datetime(now.into()).expect("datetime not set");
+
+    // In reality the delay would be much longer
+    Timer::after_millis(20000).await;
+
+    let then: NaiveDateTime = rtc.now().unwrap().into();
+    info!("Got RTC! {:?}", then.and_utc().timestamp());
+}

examples/stm32h7rs/src/bin/signal.rs

@@ -0,0 +1,36 @@
+#![no_std]
+#![no_main]
+
+use defmt::{info, unwrap};
+use embassy_executor::Spawner;
+use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+use embassy_sync::signal::Signal;
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+
+static SIGNAL: Signal<CriticalSectionRawMutex, u32> = Signal::new();
+
+#[embassy_executor::task]
+async fn my_sending_task() {
+    let mut counter: u32 = 0;
+
+    loop {
+        Timer::after_secs(1).await;
+
+        SIGNAL.signal(counter);
+
+        counter = counter.wrapping_add(1);
+    }
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let _p = embassy_stm32::init(Default::default());
+    unwrap!(spawner.spawn(my_sending_task()));
+
+    loop {
+        let received_counter = SIGNAL.wait().await;
+
+        info!("signalled, counter: {}", received_counter);
+    }
+}

examples/stm32h7rs/src/bin/spi.rs

@@ -0,0 +1,50 @@
+#![no_std]
+#![no_main]
+
+use core::fmt::Write;
+use core::str::from_utf8;
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::Executor;
+use embassy_stm32::mode::Blocking;
+use embassy_stm32::peripherals::SPI3;
+use embassy_stm32::spi;
+use embassy_stm32::time::mhz;
+use heapless::String;
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn main_task(mut spi: spi::Spi<'static, SPI3, Blocking>) {
+    for n in 0u32.. {
+        let mut write: String<128> = String::new();
+        core::write!(&mut write, "Hello DMA World {}!\r\n", n).unwrap();
+        unsafe {
+            let result = spi.blocking_transfer_in_place(write.as_bytes_mut());
+            if let Err(_) = result {
+                defmt::panic!("crap");
+            }
+        }
+        info!("read via spi: {}", from_utf8(write.as_bytes()).unwrap());
+    }
+}
+
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+    let p = embassy_stm32::init(Default::default());
+
+    let mut spi_config = spi::Config::default();
+    spi_config.frequency = mhz(1);
+
+    let spi = spi::Spi::new_blocking(p.SPI3, p.PB3, p.PB5, p.PB4, spi_config);
+
+    let executor = EXECUTOR.init(Executor::new());
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(main_task(spi)));
+    })
+}

examples/stm32h7rs/src/bin/spi_dma.rs

@@ -0,0 +1,46 @@
+#![no_std]
+#![no_main]
+
+use core::fmt::Write;
+use core::str::from_utf8;
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::Executor;
+use embassy_stm32::mode::Async;
+use embassy_stm32::time::mhz;
+use embassy_stm32::{peripherals, spi};
+use heapless::String;
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn main_task(mut spi: spi::Spi<'static, peripherals::SPI3, Async>) {
+    for n in 0u32.. {
+        let mut write: String<128> = String::new();
+        let mut read = [0; 128];
+        core::write!(&mut write, "Hello DMA World {}!\r\n", n).unwrap();
+        // transfer will slice the &mut read down to &write's actual length.
+        spi.transfer(&mut read, write.as_bytes()).await.ok();
+        info!("read via spi+dma: {}", from_utf8(&read).unwrap());
+    }
+}
+
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+    let p = embassy_stm32::init(Default::default());
+
+    let mut spi_config = spi::Config::default();
+    spi_config.frequency = mhz(1);
+
+    let spi = spi::Spi::new(p.SPI3, p.PB3, p.PB5, p.PB4, p.GPDMA1_CH0, p.GPDMA1_CH1, spi_config);
+
+    let executor = EXECUTOR.init(Executor::new());
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(main_task(spi)));
+    })
+}

examples/stm32h7rs/src/bin/usart.rs

@@ -0,0 +1,39 @@
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::Executor;
+use embassy_stm32::usart::{Config, Uart};
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::task]
+async fn main_task() {
+    let p = embassy_stm32::init(Default::default());
+
+    let config = Config::default();
+    let mut usart = Uart::new_blocking(p.UART7, p.PF6, p.PF7, config).unwrap();
+
+    unwrap!(usart.blocking_write(b"Hello Embassy World!\r\n"));
+    info!("wrote Hello, starting echo");
+
+    let mut buf = [0u8; 1];
+    loop {
+        unwrap!(usart.blocking_read(&mut buf));
+        unwrap!(usart.blocking_write(&buf));
+    }
+}
+
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.init(Executor::new());
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(main_task()));
+    })
+}

examples/stm32h7rs/src/bin/usart_dma.rs

@@ -0,0 +1,47 @@
+#![no_std]
+#![no_main]
+
+use core::fmt::Write;
+
+use cortex_m_rt::entry;
+use defmt::*;
+use embassy_executor::Executor;
+use embassy_stm32::usart::{Config, Uart};
+use embassy_stm32::{bind_interrupts, peripherals, usart};
+use heapless::String;
+use static_cell::StaticCell;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    UART7 => usart::InterruptHandler<peripherals::UART7>;
+});
+
+#[embassy_executor::task]
+async fn main_task() {
+    let p = embassy_stm32::init(Default::default());
+
+    let config = Config::default();
+    let mut usart = Uart::new(p.UART7, p.PF6, p.PF7, Irqs, p.GPDMA1_CH0, p.GPDMA1_CH1, config).unwrap();
+
+    for n in 0u32.. {
+        let mut s: String<128> = String::new();
+        core::write!(&mut s, "Hello DMA World {}!\r\n", n).unwrap();
+
+        usart.write(s.as_bytes()).await.ok();
+
+        info!("wrote DMA");
+    }
+}
+
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.init(Executor::new());
+
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(main_task()));
+    })
+}

examples/stm32h7rs/src/bin/usart_split.rs

@@ -0,0 +1,48 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::mode::Async;
+use embassy_stm32::peripherals::UART7;
+use embassy_stm32::usart::{Config, Uart, UartRx};
+use embassy_stm32::{bind_interrupts, peripherals, usart};
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
+use {defmt_rtt as _, panic_probe as _};
+
+bind_interrupts!(struct Irqs {
+    UART7 => usart::InterruptHandler<peripherals::UART7>;
+});
+
+static CHANNEL: Channel<ThreadModeRawMutex, [u8; 8], 1> = Channel::new();
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) -> ! {
+    let p = embassy_stm32::init(Default::default());
+    info!("Hello World!");
+
+    let config = Config::default();
+    let mut usart = Uart::new(p.UART7, p.PF6, p.PF7, Irqs, p.GPDMA1_CH0, p.GPDMA1_CH1, config).unwrap();
+    unwrap!(usart.blocking_write(b"Type 8 chars to echo!\r\n"));
+
+    let (mut tx, rx) = usart.split();
+
+    unwrap!(spawner.spawn(reader(rx)));
+
+    loop {
+        let buf = CHANNEL.receive().await;
+        info!("writing...");
+        unwrap!(tx.write(&buf).await);
+    }
+}
+
+#[embassy_executor::task]
+async fn reader(mut rx: UartRx<'static, UART7, Async>) {
+    let mut buf = [0; 8];
+    loop {
+        info!("reading...");
+        unwrap!(rx.read(&mut buf).await);
+        CHANNEL.send(buf).await;
+    }
+}