Rename examples -> embassy-nrf-examples

embassy-nrf-examples/.cargo/config

@@ -0,0 +1,27 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+runner = "probe-run --chip nRF52840_xxAA --defmt"
+
+rustflags = [
+  # LLD (shipped with the Rust toolchain) is used as the default linker
+  "-C", "link-arg=--nmagic",
+  "-C", "link-arg=-Tlink.x",
+  "-C", "link-arg=-Tdefmt.x",
+
+  # if you run into problems with LLD switch to the GNU linker by commenting out
+  # this line
+  # "-C", "linker=arm-none-eabi-ld",
+
+  # if you need to link to pre-compiled C libraries provided by a C toolchain
+  # use GCC as the linker by commenting out both lines above and then
+  # uncommenting the three lines below
+  # "-C", "linker=arm-none-eabi-gcc",
+  # "-C", "link-arg=-Wl,-Tlink.x",
+  # "-C", "link-arg=-nostartfiles",
+]
+
+[build]
+# Pick ONE of these compilation targets
+# target = "thumbv6m-none-eabi"    # Cortex-M0 and Cortex-M0+
+# target = "thumbv7m-none-eabi"    # Cortex-M3
+# target = "thumbv7em-none-eabi"   # Cortex-M4 and Cortex-M7 (no FPU)
+target = "thumbv7em-none-eabihf" # Cortex-M4F and Cortex-M7F (with FPU)

embassy-nrf-examples/Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+authors = ["Dario Nieuwenhuis <dirbaio@dirbaio.net>"]
+edition = "2018"
+name = "embassy-nrf-examples"
+version = "0.1.0"
+
+[features]
+default = [
+    "defmt-default",
+]
+defmt-default = []
+defmt-trace = []
+defmt-debug = []
+defmt-info = []
+defmt-warn = []
+defmt-error = []
+
+
+[dependencies]
+embassy = { version = "0.1.0", path = "../embassy", features = ["defmt", "defmt-trace"] }
+embassy-nrf = { version = "0.1.0", path = "../embassy-nrf", features = ["defmt", "defmt-trace", "52840"] }
+
+defmt = "0.1.3"
+defmt-rtt = "0.1.0"
+
+cortex-m        = { version = "0.6.3" }
+cortex-m-rt = "0.6.13"
+embedded-hal    = { version = "0.2.4" }
+panic-probe = "0.1.0"
+nrf52840-hal    = { version = "0.12.0" }
+futures = { version = "0.3.8", default-features = false, features = ["async-await"] }
+cortex-m-rtic = { git = "https://github.com/rtic-rs/cortex-m-rtic", branch = "master"}

embassy-nrf-examples/build.rs

@@ -0,0 +1,31 @@
+//! This build script copies the `memory.x` file from the crate root into
+//! a directory where the linker can always find it at build time.
+//! For many projects this is optional, as the linker always searches the
+//! project root directory -- wherever `Cargo.toml` is. However, if you
+//! are using a workspace or have a more complicated build setup, this
+//! build script becomes required. Additionally, by requesting that
+//! Cargo re-run the build script whenever `memory.x` is changed,
+//! updating `memory.x` ensures a rebuild of the application with the
+//! new memory settings.
+
+use std::env;
+use std::fs::File;
+use std::io::Write;
+use std::path::PathBuf;
+
+fn main() {
+    // Put `memory.x` in our output directory and ensure it's
+    // on the linker search path.
+    let out = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
+    File::create(out.join("memory.x"))
+        .unwrap()
+        .write_all(include_bytes!("memory.x"))
+        .unwrap();
+    println!("cargo:rustc-link-search={}", out.display());
+
+    // By default, Cargo will re-run a build script whenever
+    // any file in the project changes. By specifying `memory.x`
+    // here, we ensure the build script is only re-run when
+    // `memory.x` is changed.
+    println!("cargo:rerun-if-changed=memory.x");
+}

embassy-nrf-examples/memory.x

@@ -0,0 +1,7 @@
+MEMORY
+{
+  /* NOTE 1 K = 1 KiBi = 1024 bytes */
+  /* These values correspond to the NRF52840 with Softdevices S140 7.0.1 */
+  FLASH : ORIGIN = 0x00000000, LENGTH = 1024K
+  RAM : ORIGIN = 0x20000000, LENGTH = 256K
+}

embassy-nrf-examples/src/bin/buffered_uart.rs

@@ -0,0 +1,84 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use cortex_m_rt::entry;
+use defmt::panic;
+use futures::pin_mut;
+use nrf52840_hal::gpio;
+
+use embassy::executor::{task, Executor};
+use embassy::io::{AsyncBufRead, AsyncBufReadExt, AsyncWrite, AsyncWriteExt};
+use embassy::util::Forever;
+use embassy_nrf::buffered_uarte;
+use embassy_nrf::interrupt;
+
+#[task]
+async fn run() {
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    let port0 = gpio::p0::Parts::new(p.P0);
+
+    let pins = buffered_uarte::Pins {
+        rxd: port0.p0_08.into_floating_input().degrade(),
+        txd: port0
+            .p0_06
+            .into_push_pull_output(gpio::Level::Low)
+            .degrade(),
+        cts: None,
+        rts: None,
+    };
+
+    let irq = interrupt::take!(UARTE0_UART0);
+    let u = buffered_uarte::BufferedUarte::new(
+        p.UARTE0,
+        irq,
+        pins,
+        buffered_uarte::Parity::EXCLUDED,
+        buffered_uarte::Baudrate::BAUD115200,
+    );
+    pin_mut!(u);
+
+    info!("uarte initialized!");
+
+    unwrap!(u.write_all(b"Hello!\r\n").await);
+    info!("wrote hello in uart!");
+
+    // Simple demo, reading 8-char chunks and echoing them back reversed.
+    loop {
+        info!("reading...");
+        let mut buf = [0u8; 8];
+        unwrap!(u.read_exact(&mut buf).await);
+        info!("read done, got {:[u8]}", buf);
+
+        // Reverse buf
+        for i in 0..4 {
+            let tmp = buf[i];
+            buf[i] = buf[7 - i];
+            buf[7 - i] = tmp;
+        }
+
+        info!("writing...");
+        unwrap!(u.write_all(&buf).await);
+        info!("write done");
+    }
+}
+
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.put(Executor::new(cortex_m::asm::sev));
+    unwrap!(executor.spawn(run()));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/bin/executor_fairness_test.rs

@@ -0,0 +1,74 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use core::task::Poll;
+use cortex_m_rt::entry;
+use defmt::panic;
+use embassy::executor::{task, Executor};
+use embassy::time::{Duration, Instant, Timer};
+use embassy::util::Forever;
+use embassy_nrf::pac;
+use embassy_nrf::{interrupt, rtc};
+use nrf52840_hal::clocks;
+
+#[task]
+async fn run1() {
+    loop {
+        info!("DING DONG");
+        Timer::after(Duration::from_ticks(16000)).await;
+    }
+}
+
+#[task]
+async fn run2() {
+    loop {
+        Timer::at(Instant::from_ticks(0)).await;
+    }
+}
+
+#[task]
+async fn run3() {
+    futures::future::poll_fn(|cx| {
+        cx.waker().wake_by_ref();
+        Poll::<()>::Pending
+    })
+    .await;
+}
+
+static RTC: Forever<rtc::RTC<pac::RTC1>> = Forever::new();
+static ALARM: Forever<rtc::Alarm<pac::RTC1>> = Forever::new();
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    clocks::Clocks::new(p.CLOCK)
+        .enable_ext_hfosc()
+        .set_lfclk_src_external(clocks::LfOscConfiguration::NoExternalNoBypass)
+        .start_lfclk();
+
+    let rtc = RTC.put(rtc::RTC::new(p.RTC1, interrupt::take!(RTC1)));
+    rtc.start();
+
+    unsafe { embassy::time::set_clock(rtc) };
+
+    let alarm = ALARM.put(rtc.alarm0());
+    let executor = EXECUTOR.put(Executor::new_with_alarm(alarm, cortex_m::asm::sev));
+
+    unwrap!(executor.spawn(run1()));
+    unwrap!(executor.spawn(run2()));
+    unwrap!(executor.spawn(run3()));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/bin/gpiote.rs

@@ -0,0 +1,83 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use cortex_m_rt::entry;
+use defmt::panic;
+use nrf52840_hal::gpio;
+
+use embassy::executor::{task, Executor};
+use embassy::util::Forever;
+use embassy_nrf::gpiote;
+use embassy_nrf::interrupt;
+
+#[task]
+async fn run() {
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+    let port0 = gpio::p0::Parts::new(p.P0);
+
+    let g = gpiote::Gpiote::new(p.GPIOTE, interrupt::take!(GPIOTE));
+
+    info!("Starting!");
+
+    let pin1 = port0.p0_11.into_pullup_input().degrade();
+    let button1 = async {
+        let ch = unwrap!(g.new_input_channel(pin1, gpiote::InputChannelPolarity::HiToLo));
+
+        loop {
+            ch.wait().await;
+            info!("Button 1 pressed")
+        }
+    };
+
+    let pin2 = port0.p0_12.into_pullup_input().degrade();
+    let button2 = async {
+        let ch = unwrap!(g.new_input_channel(pin2, gpiote::InputChannelPolarity::LoToHi));
+
+        loop {
+            ch.wait().await;
+            info!("Button 2 released")
+        }
+    };
+
+    let pin3 = port0.p0_24.into_pullup_input().degrade();
+    let button3 = async {
+        let ch = unwrap!(g.new_input_channel(pin3, gpiote::InputChannelPolarity::Toggle));
+
+        loop {
+            ch.wait().await;
+            info!("Button 3 toggled")
+        }
+    };
+
+    let pin4 = port0.p0_25.into_pullup_input().degrade();
+    let button4 = async {
+        let ch = unwrap!(g.new_input_channel(pin4, gpiote::InputChannelPolarity::Toggle));
+
+        loop {
+            ch.wait().await;
+            info!("Button 4 toggled")
+        }
+    };
+
+    futures::join!(button1, button2, button3, button4);
+}
+
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.put(Executor::new(cortex_m::asm::sev));
+    unwrap!(executor.spawn(run()));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/bin/gpiote_port.rs

@@ -0,0 +1,62 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use core::mem;
+use cortex_m_rt::entry;
+use defmt::panic;
+use nrf52840_hal::gpio;
+
+use embassy::executor::{task, Executor};
+use embassy::util::Forever;
+use embassy_nrf::gpiote::{Gpiote, PortInputPolarity};
+use embassy_nrf::interrupt;
+
+async fn button(g: &Gpiote, n: usize, pin: gpio::Pin<gpio::Input<gpio::PullUp>>) {
+    loop {
+        g.wait_port_input(&pin, PortInputPolarity::Low).await;
+        info!("Button {:?} pressed!", n);
+        g.wait_port_input(&pin, PortInputPolarity::High).await;
+        info!("Button {:?} released!", n);
+    }
+}
+
+#[task]
+async fn run() {
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+    let port0 = gpio::p0::Parts::new(p.P0);
+
+    let g = Gpiote::new(p.GPIOTE, interrupt::take!(GPIOTE));
+    info!(
+        "sizeof Signal<()> = {:usize}",
+        mem::size_of::<embassy::util::Signal<()>>()
+    );
+    info!("sizeof gpiote = {:usize}", mem::size_of::<Gpiote>());
+
+    info!("Starting!");
+
+    let button1 = button(&g, 1, port0.p0_11.into_pullup_input().degrade());
+    let button2 = button(&g, 2, port0.p0_12.into_pullup_input().degrade());
+    let button3 = button(&g, 3, port0.p0_24.into_pullup_input().degrade());
+    let button4 = button(&g, 4, port0.p0_25.into_pullup_input().degrade());
+    futures::join!(button1, button2, button3, button4);
+}
+
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.put(Executor::new(cortex_m::asm::sev));
+    unwrap!(executor.spawn(run()));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/bin/multiprio.rs

@@ -0,0 +1,176 @@
+//! 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]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use cortex_m::peripheral::NVIC;
+use cortex_m_rt::entry;
+use defmt::panic;
+use nrf52840_hal::clocks;
+
+use embassy::executor::{task, Executor};
+use embassy::time::{Duration, Instant, Timer};
+use embassy::util::Forever;
+use embassy_nrf::{interrupt, pac, rtc};
+
+#[task]
+async fn run_high() {
+    loop {
+        info!("        [high] tick!");
+        Timer::after(Duration::from_ticks(27374)).await;
+    }
+}
+
+#[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(32_000_000); // ~1 second
+
+        let end = Instant::now();
+        let ms = end.duration_since(start).as_ticks() / 33;
+        info!("    [med] done in {:u64} ms", ms);
+
+        Timer::after(Duration::from_ticks(23421)).await;
+    }
+}
+
+#[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(64_000_000); // ~2 seconds
+
+        let end = Instant::now();
+        let ms = end.duration_since(start).as_ticks() / 33;
+        info!("[low] done in {:u64} ms", ms);
+
+        Timer::after(Duration::from_ticks(32983)).await;
+    }
+}
+
+static RTC: Forever<rtc::RTC<pac::RTC1>> = Forever::new();
+static ALARM_LOW: Forever<rtc::Alarm<pac::RTC1>> = Forever::new();
+static EXECUTOR_LOW: Forever<Executor> = Forever::new();
+static ALARM_MED: Forever<rtc::Alarm<pac::RTC1>> = Forever::new();
+static EXECUTOR_MED: Forever<Executor> = Forever::new();
+static ALARM_HIGH: Forever<rtc::Alarm<pac::RTC1>> = Forever::new();
+static EXECUTOR_HIGH: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    clocks::Clocks::new(p.CLOCK)
+        .enable_ext_hfosc()
+        .set_lfclk_src_external(clocks::LfOscConfiguration::NoExternalNoBypass)
+        .start_lfclk();
+
+    let rtc = RTC.put(rtc::RTC::new(p.RTC1, interrupt::take!(RTC1)));
+    rtc.start();
+    unsafe { embassy::time::set_clock(rtc) };
+
+    let alarm_low = ALARM_LOW.put(rtc.alarm0());
+    let executor_low = EXECUTOR_LOW.put(Executor::new_with_alarm(alarm_low, cortex_m::asm::sev));
+    let alarm_med = ALARM_MED.put(rtc.alarm1());
+    let executor_med = EXECUTOR_MED.put(Executor::new_with_alarm(alarm_med, || {
+        NVIC::pend(interrupt::SWI0_EGU0)
+    }));
+    let alarm_high = ALARM_HIGH.put(rtc.alarm2());
+    let executor_high = EXECUTOR_HIGH.put(Executor::new_with_alarm(alarm_high, || {
+        NVIC::pend(interrupt::SWI1_EGU1)
+    }));
+
+    unsafe {
+        let mut nvic: NVIC = core::mem::transmute(());
+        nvic.set_priority(interrupt::SWI0_EGU0, 7 << 5);
+        nvic.set_priority(interrupt::SWI1_EGU1, 6 << 5);
+        NVIC::unmask(interrupt::SWI0_EGU0);
+        NVIC::unmask(interrupt::SWI1_EGU1);
+    }
+
+    unwrap!(executor_low.spawn(run_low()));
+    unwrap!(executor_med.spawn(run_med()));
+    unwrap!(executor_high.spawn(run_high()));
+
+    loop {
+        executor_low.run();
+        cortex_m::asm::wfe();
+    }
+}
+
+#[interrupt]
+unsafe fn SWI0_EGU0() {
+    EXECUTOR_MED.steal().run()
+}
+
+#[interrupt]
+unsafe fn SWI1_EGU1() {
+    EXECUTOR_HIGH.steal().run()
+}

embassy-nrf-examples/src/bin/qspi.rs

@@ -0,0 +1,134 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use cortex_m_rt::entry;
+use defmt::{assert_eq, panic, *};
+use nrf52840_hal::gpio;
+
+use embassy::executor::{task, Executor};
+use embassy::flash::Flash;
+use embassy::util::Forever;
+use embassy_nrf::{interrupt, qspi};
+
+const PAGE_SIZE: usize = 4096;
+
+// Workaround for alignment requirements.
+// Nicer API will probably come in the future.
+#[repr(C, align(4))]
+struct AlignedBuf([u8; 4096]);
+
+#[task]
+async fn run() {
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    let port0 = gpio::p0::Parts::new(p.P0);
+
+    let pins = qspi::Pins {
+        csn: port0
+            .p0_17
+            .into_push_pull_output(gpio::Level::High)
+            .degrade(),
+        sck: port0
+            .p0_19
+            .into_push_pull_output(gpio::Level::High)
+            .degrade(),
+        io0: port0
+            .p0_20
+            .into_push_pull_output(gpio::Level::High)
+            .degrade(),
+        io1: port0
+            .p0_21
+            .into_push_pull_output(gpio::Level::High)
+            .degrade(),
+        io2: Some(
+            port0
+                .p0_22
+                .into_push_pull_output(gpio::Level::High)
+                .degrade(),
+        ),
+        io3: Some(
+            port0
+                .p0_23
+                .into_push_pull_output(gpio::Level::High)
+                .degrade(),
+        ),
+    };
+
+    let config = qspi::Config {
+        pins,
+        read_opcode: qspi::ReadOpcode::READ4IO,
+        write_opcode: qspi::WriteOpcode::PP4IO,
+        xip_offset: 0,
+        write_page_size: qspi::WritePageSize::_256BYTES,
+        deep_power_down: None,
+    };
+
+    let irq = interrupt::take!(QSPI);
+    let mut q = qspi::Qspi::new(p.QSPI, irq, config);
+
+    let mut id = [1; 3];
+    q.custom_instruction(0x9F, &[], &mut id).await.unwrap();
+    info!("id: {:[u8]}", id);
+
+    // Read status register
+    let mut status = [0; 1];
+    q.custom_instruction(0x05, &[], &mut status).await.unwrap();
+
+    info!("status: {:?}", status[0]);
+
+    if status[0] & 0x40 == 0 {
+        status[0] |= 0x40;
+
+        q.custom_instruction(0x01, &status, &mut []).await.unwrap();
+
+        info!("enabled quad in status");
+    }
+
+    let mut buf = AlignedBuf([0u8; PAGE_SIZE]);
+
+    let pattern = |a: u32| (a ^ (a >> 8) ^ (a >> 16) ^ (a >> 24)) as u8;
+
+    for i in 0..8 {
+        info!("page {:?}: erasing... ", i);
+        q.erase(i * PAGE_SIZE).await.unwrap();
+
+        for j in 0..PAGE_SIZE {
+            buf.0[j] = pattern((j + i * PAGE_SIZE) as u32);
+        }
+
+        info!("programming...");
+        q.write(i * PAGE_SIZE, &buf.0).await.unwrap();
+    }
+
+    for i in 0..8 {
+        info!("page {:?}: reading... ", i);
+        q.read(i * PAGE_SIZE, &mut buf.0).await.unwrap();
+
+        info!("verifying...");
+        for j in 0..PAGE_SIZE {
+            assert_eq!(buf.0[j], pattern((j + i * PAGE_SIZE) as u32));
+        }
+    }
+
+    info!("done!")
+}
+
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.put(Executor::new(cortex_m::asm::sev));
+    unwrap!(executor.spawn(run()));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/bin/rtc_async.rs

@@ -0,0 +1,65 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use core::mem::MaybeUninit;
+use cortex_m_rt::entry;
+use defmt::panic;
+use embassy::executor::{task, Executor};
+use embassy::time::{Clock, Duration, Timer};
+use embassy::util::Forever;
+use embassy_nrf::pac;
+use embassy_nrf::{interrupt, rtc};
+use nrf52840_hal::clocks;
+
+#[task]
+async fn run1() {
+    loop {
+        info!("BIG INFREQUENT TICK");
+        Timer::after(Duration::from_ticks(64000)).await;
+    }
+}
+
+#[task]
+async fn run2() {
+    loop {
+        info!("tick");
+        Timer::after(Duration::from_ticks(13000)).await;
+    }
+}
+
+static RTC: Forever<rtc::RTC<pac::RTC1>> = Forever::new();
+static ALARM: Forever<rtc::Alarm<pac::RTC1>> = Forever::new();
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    clocks::Clocks::new(p.CLOCK)
+        .enable_ext_hfosc()
+        .set_lfclk_src_external(clocks::LfOscConfiguration::NoExternalNoBypass)
+        .start_lfclk();
+
+    let rtc = RTC.put(rtc::RTC::new(p.RTC1, interrupt::take!(RTC1)));
+    rtc.start();
+
+    unsafe { embassy::time::set_clock(rtc) };
+
+    let alarm = ALARM.put(rtc.alarm0());
+    let executor = EXECUTOR.put(Executor::new_with_alarm(alarm, cortex_m::asm::sev));
+
+    unwrap!(executor.spawn(run1()));
+    unwrap!(executor.spawn(run2()));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/bin/rtc_raw.rs

@@ -0,0 +1,63 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use core::mem::MaybeUninit;
+use cortex_m_rt::entry;
+use defmt::panic;
+use embassy::time::{Alarm, Clock};
+use embassy_nrf::{interrupt, rtc};
+use nrf52840_hal::clocks;
+
+static mut RTC: MaybeUninit<rtc::RTC<embassy_nrf::pac::RTC1>> = MaybeUninit::uninit();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    clocks::Clocks::new(p.CLOCK)
+        .enable_ext_hfosc()
+        .set_lfclk_src_external(clocks::LfOscConfiguration::NoExternalNoBypass)
+        .start_lfclk();
+
+    let irq = interrupt::take!(RTC1);
+
+    let rtc: &'static _ = unsafe {
+        let ptr = RTC.as_mut_ptr();
+        ptr.write(rtc::RTC::new(p.RTC1, irq));
+        &*ptr
+    };
+
+    let alarm = rtc.alarm0();
+
+    rtc.start();
+
+    alarm.set_callback(|| info!("ALARM TRIGGERED"));
+    alarm.set(53719);
+
+    info!("initialized!");
+
+    let mut val = 0;
+    let mut printval = 0;
+    loop {
+        let val2 = rtc.now();
+        if val2 < val {
+            info!(
+                "timer ran backwards! {:u32} -> {:u32}",
+                val as u32, val2 as u32
+            );
+        }
+        val = val2;
+
+        if val > printval + 32768 {
+            info!("tick {:u32}", val as u32);
+            printval = val;
+        }
+    }
+}

embassy-nrf-examples/src/bin/uart.rs

@@ -0,0 +1,107 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use cortex_m_rt::entry;
+use defmt::panic;
+use embassy::executor::{task, Executor};
+use embassy::time::{Duration, Timer};
+use embassy::util::Forever;
+use embassy_nrf::{interrupt, pac, rtc, uarte};
+use futures::future::{select, Either};
+use nrf52840_hal::clocks;
+use nrf52840_hal::gpio;
+
+#[task]
+async fn run(mut uart: uarte::Uarte<pac::UARTE0>) {
+    info!("uarte initialized!");
+
+    // Message must be in SRAM
+    let mut buf = [0; 8];
+    buf.copy_from_slice(b"Hello!\r\n");
+
+    uart.send(&buf).await;
+    info!("wrote hello in uart!");
+
+    info!("reading...");
+    loop {
+        let received = match select(
+            uart.receive(&mut buf),
+            Timer::after(Duration::from_millis(10)),
+        )
+        .await
+        {
+            Either::Left((buf, _)) => buf,
+            Either::Right((_, read)) => {
+                let (buf, n) = read.stop().await;
+                &buf[..n]
+            }
+        };
+
+        if received.len() > 0 {
+            info!("read done, got {:[u8]}", received);
+
+            // Echo back received data
+            uart.send(received).await;
+        }
+    }
+}
+
+static RTC: Forever<rtc::RTC<pac::RTC1>> = Forever::new();
+static ALARM: Forever<rtc::Alarm<pac::RTC1>> = Forever::new();
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let p = unwrap!(embassy_nrf::pac::Peripherals::take());
+
+    clocks::Clocks::new(p.CLOCK)
+        .enable_ext_hfosc()
+        .set_lfclk_src_external(clocks::LfOscConfiguration::NoExternalNoBypass)
+        .start_lfclk();
+
+    let rtc = RTC.put(rtc::RTC::new(p.RTC1, interrupt::take!(RTC1)));
+    rtc.start();
+
+    unsafe { embassy::time::set_clock(rtc) };
+
+    let alarm = ALARM.put(rtc.alarm0());
+    let executor = EXECUTOR.put(Executor::new_with_alarm(alarm, cortex_m::asm::sev));
+
+    // Init UART
+    let port0 = gpio::p0::Parts::new(p.P0);
+
+    let pins = uarte::Pins {
+        rxd: port0.p0_08.into_floating_input().degrade(),
+        txd: port0
+            .p0_06
+            .into_push_pull_output(gpio::Level::Low)
+            .degrade(),
+        cts: None,
+        rts: None,
+    };
+
+    // NOTE(unsafe): Safe becasue we do not use `mem::forget` anywhere.
+    let uart = unsafe {
+        uarte::Uarte::new(
+            p.UARTE0,
+            interrupt::take!(UARTE0_UART0),
+            pins,
+            uarte::Parity::EXCLUDED,
+            uarte::Baudrate::BAUD115200,
+        )
+    };
+
+    unwrap!(executor.spawn(run(uart)));
+
+    loop {
+        executor.run();
+        cortex_m::asm::wfe();
+    }
+}

embassy-nrf-examples/src/example_common.rs

@@ -0,0 +1,18 @@
+#![macro_use]
+
+use defmt_rtt as _; // global logger
+use nrf52840_hal as _;
+use panic_probe as _;
+
+pub use defmt::*;
+
+use core::sync::atomic::{AtomicUsize, Ordering};
+
+#[defmt::timestamp]
+fn timestamp() -> u64 {
+    static COUNT: AtomicUsize = AtomicUsize::new(0);
+    // NOTE(no-CAS) `timestamps` runs with interrupts disabled
+    let n = COUNT.load(Ordering::Relaxed);
+    COUNT.store(n + 1, Ordering::Relaxed);
+    n as u64
+}