Merge remote-tracking branch 'origin/master' into nrf-pdm

62 files changed, 316 insertions, 151 deletions

diff --git a/examples/boot/application/nrf/Cargo.toml b/examples/boot/application/nrf/Cargo.toml
index ef9346639..b9ff92578 100644
--- a/examples/boot/application/nrf/Cargo.toml
+++ b/examples/boot/application/nrf/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-nrf-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util" }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync" }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly"] }
 embassy-nrf = { version = "0.1.0", path = "../../../../embassy-nrf", features = ["time-driver-rtc1", "gpiote", "nightly", "nrf52840"] }
diff --git a/examples/boot/application/stm32f3/Cargo.toml b/examples/boot/application/stm32f3/Cargo.toml
index 27eafa653..f143d1e8d 100644
--- a/examples/boot/application/stm32f3/Cargo.toml
+++ b/examples/boot/application/stm32f3/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32f3-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32f303re", "time-driver-any", "exti"]  }
diff --git a/examples/boot/application/stm32f7/Cargo.toml b/examples/boot/application/stm32f7/Cargo.toml
index 7de0b82d7..29c87eee1 100644
--- a/examples/boot/application/stm32f7/Cargo.toml
+++ b/examples/boot/application/stm32f7/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32f7-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32f767zi", "time-driver-any", "exti"]  }
diff --git a/examples/boot/application/stm32h7/Cargo.toml b/examples/boot/application/stm32h7/Cargo.toml
index 65d34c70b..5669527fe 100644
--- a/examples/boot/application/stm32h7/Cargo.toml
+++ b/examples/boot/application/stm32h7/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32h7-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32h743zi", "time-driver-any", "exti"]  }
diff --git a/examples/boot/application/stm32l0/Cargo.toml b/examples/boot/application/stm32l0/Cargo.toml
index 8f37869e3..48624d5ec 100644
--- a/examples/boot/application/stm32l0/Cargo.toml
+++ b/examples/boot/application/stm32l0/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32l0-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32l072cz", "time-driver-any", "exti", "memory-x"]  }
diff --git a/examples/boot/application/stm32l1/Cargo.toml b/examples/boot/application/stm32l1/Cargo.toml
index 6abf1986d..00b638ca5 100644
--- a/examples/boot/application/stm32l1/Cargo.toml
+++ b/examples/boot/application/stm32l1/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32l1-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32l151cb-a", "time-driver-any", "exti"]  }
diff --git a/examples/boot/application/stm32l4/Cargo.toml b/examples/boot/application/stm32l4/Cargo.toml
index 6f2d12ff1..51ba730d5 100644
--- a/examples/boot/application/stm32l4/Cargo.toml
+++ b/examples/boot/application/stm32l4/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32l4-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32l475vg", "time-driver-any", "exti"]  }
diff --git a/examples/boot/application/stm32wl/Cargo.toml b/examples/boot/application/stm32wl/Cargo.toml
index be97d4ebb..182acf694 100644
--- a/examples/boot/application/stm32wl/Cargo.toml
+++ b/examples/boot/application/stm32wl/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-boot-stm32wl-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../../../embassy-executor", features = ["nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../../../embassy-time", features = ["nightly", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../../../embassy-stm32", features = ["unstable-traits", "nightly", "stm32wl55jc-cm4", "time-driver-any", "exti"]  }
diff --git a/examples/nrf-rtos-trace/.cargo/config.toml b/examples/nrf-rtos-trace/.cargo/config.toml
new file mode 100644
index 000000000..8ca28df39
--- /dev/null
+++ b/examples/nrf-rtos-trace/.cargo/config.toml
@@ -0,0 +1,9 @@
+[target.'cfg(all(target_arch = "arm", target_os = "none"))']
+# replace nRF82840_xxAA with your chip as listed in `probe-run --list-chips`
+runner = "probe-run --chip nRF52840_xxAA"
+
+[build]
+target = "thumbv7em-none-eabi"
+
+[env]
+DEFMT_LOG = "trace"
diff --git a/examples/nrf-rtos-trace/Cargo.toml b/examples/nrf-rtos-trace/Cargo.toml
new file mode 100644
index 000000000..87c9f33f5
--- /dev/null
+++ b/examples/nrf-rtos-trace/Cargo.toml
@@ -0,0 +1,35 @@
+[package]
+edition = "2021"
+name = "embassy-nrf-rtos-trace-examples"
+version = "0.1.0"
+
+[features]
+default = ["log", "nightly"]
+nightly = ["embassy-executor/nightly", "embassy-nrf/nightly", "embassy-nrf/unstable-traits"]
+log = [
+    "dep:log",
+    "embassy-sync/log",
+    "embassy-executor/log",
+    "embassy-time/log",
+    "embassy-nrf/log",
+]
+
+[dependencies]
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync" }
+embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features=["rtos-trace", "rtos-trace-interrupt", "integrated-timers"] }
+embassy-time = { version = "0.1.0", path = "../../embassy-time" }
+embassy-nrf = { version = "0.1.0", path = "../../embassy-nrf", features = ["nrf52840", "time-driver-rtc1", "gpiote", "unstable-pac"] }
+
+cortex-m = { version = "0.7.6", features = ["critical-section-single-core"] }
+cortex-m-rt = "0.7.0"
+panic-probe = { version = "0.3" }
+futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
+rand = { version = "0.8.4", default-features = false }
+serde = { version = "1.0.136", default-features = false }
+rtos-trace = "0.1.3"
+systemview-target = { version = "0.1.2", features = ["callbacks-app", "callbacks-os", "log", "cortex-m"] }
+log = { version = "0.4.17", optional = true }
+
+[[bin]]
+name = "rtos_trace"
+required-features = ["nightly"]
diff --git a/examples/nrf-rtos-trace/build.rs b/examples/nrf-rtos-trace/build.rs
new file mode 100644
index 000000000..36cdb65a8
--- /dev/null
+++ b/examples/nrf-rtos-trace/build.rs
@@ -0,0 +1,36 @@
+//! 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");
+
+    println!("cargo:rustc-link-arg-bins=--nmagic");
+    println!("cargo:rustc-link-arg-bins=-Tlink.x");
+    #[cfg(feature = "defmt")]
+    println!("cargo:rustc-link-arg-bins=-Tdefmt.x");
+}
diff --git a/examples/nrf-rtos-trace/memory.x b/examples/nrf-rtos-trace/memory.x
new file mode 100644
index 000000000..9b04edec0
--- /dev/null
+++ b/examples/nrf-rtos-trace/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
+}
diff --git a/examples/nrf-rtos-trace/src/bin/rtos_trace.rs b/examples/nrf-rtos-trace/src/bin/rtos_trace.rs
new file mode 100644
index 000000000..7d1ad87c8
--- /dev/null
+++ b/examples/nrf-rtos-trace/src/bin/rtos_trace.rs
@@ -0,0 +1,69 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use core::task::Poll;
+
+use embassy_executor::Spawner;
+use embassy_time::{Duration, Instant, Timer};
+#[cfg(feature = "log")]
+use log::*;
+use panic_probe as _;
+// N.B. systemview_target cannot be used at the same time as defmt_rtt.
+use rtos_trace;
+use systemview_target::SystemView;
+
+static LOGGER: systemview_target::SystemView = systemview_target::SystemView::new();
+rtos_trace::global_trace! {SystemView}
+
+struct TraceInfo();
+
+impl rtos_trace::RtosTraceApplicationCallbacks for TraceInfo {
+    fn system_description() {}
+    fn sysclock() -> u32 {
+        64000000
+    }
+}
+rtos_trace::global_application_callbacks! {TraceInfo}
+
+#[embassy_executor::task]
+async fn run1() {
+    loop {
+        #[cfg(feature = "log")]
+        info!("DING DONG");
+        #[cfg(not(feature = "log"))]
+        rtos_trace::trace::marker(13);
+        Timer::after(Duration::from_ticks(16000)).await;
+    }
+}
+
+#[embassy_executor::task]
+async fn run2() {
+    loop {
+        Timer::at(Instant::from_ticks(0)).await;
+    }
+}
+
+#[embassy_executor::task]
+async fn run3() {
+    futures::future::poll_fn(|cx| {
+        cx.waker().wake_by_ref();
+        Poll::<()>::Pending
+    })
+    .await;
+}
+
+#[embassy_executor::main]
+async fn main(spawner: Spawner) {
+    let _p = embassy_nrf::init(Default::default());
+    LOGGER.init();
+    #[cfg(feature = "log")]
+    {
+        ::log::set_logger(&LOGGER).ok();
+        ::log::set_max_level(::log::LevelFilter::Trace);
+    }
+
+    spawner.spawn(run1()).unwrap();
+    spawner.spawn(run2()).unwrap();
+    spawner.spawn(run3()).unwrap();
+}
diff --git a/examples/nrf/Cargo.toml b/examples/nrf/Cargo.toml
index 876dcf734..8309dda08 100644
--- a/examples/nrf/Cargo.toml
+++ b/examples/nrf/Cargo.toml
@@ -8,7 +8,8 @@ default = ["nightly"]
 nightly = ["embassy-executor/nightly", "embassy-nrf/nightly", "embassy-nrf/unstable-traits", "embassy-usb", "embassy-usb-serial", "embassy-usb-hid", "embassy-usb-ncm", "embedded-io/async", "embassy-net"]
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-futures = { version = "0.1.0", path = "../../embassy-futures" }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime"] }
 embassy-nrf = { version = "0.1.0", path = "../../embassy-nrf", features = ["defmt", "nrf52840", "time-driver-rtc1", "gpiote", "unstable-pac"] }
@@ -22,6 +23,7 @@ embedded-io = "0.3.0"
 defmt = "0.3"
 defmt-rtt = "0.3"
 
+static_cell = "1.0"
 cortex-m = { version = "0.7.6", features = ["critical-section-single-core"] }
 cortex-m-rt = "0.7.0"
 panic-probe = { version = "0.3", features = ["print-defmt"] }
diff --git a/examples/nrf/src/bin/channel.rs b/examples/nrf/src/bin/channel.rs
index 195200988..d782a79e7 100644
--- a/examples/nrf/src/bin/channel.rs
+++ b/examples/nrf/src/bin/channel.rs
@@ -5,9 +5,9 @@
 use defmt::unwrap;
 use embassy_executor::Spawner;
 use embassy_nrf::gpio::{Level, Output, OutputDrive};
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
 use embassy_time::{Duration, Timer};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::mpmc::Channel;
 use {defmt_rtt as _, panic_probe as _};
 
 enum LedState {
diff --git a/examples/nrf/src/bin/channel_sender_receiver.rs b/examples/nrf/src/bin/channel_sender_receiver.rs
index c9c458aec..fcccdaed5 100644
--- a/examples/nrf/src/bin/channel_sender_receiver.rs
+++ b/examples/nrf/src/bin/channel_sender_receiver.rs
@@ -5,10 +5,10 @@
 use defmt::unwrap;
 use embassy_executor::Spawner;
 use embassy_nrf::gpio::{AnyPin, Level, Output, OutputDrive, Pin};
+use embassy_sync::blocking_mutex::raw::NoopRawMutex;
+use embassy_sync::channel::{Channel, Receiver, Sender};
 use embassy_time::{Duration, Timer};
-use embassy_util::blocking_mutex::raw::NoopRawMutex;
-use embassy_util::channel::mpmc::{Channel, Receiver, Sender};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 enum LedState {
@@ -16,7 +16,7 @@ enum LedState {
     Off,
 }
 
-static CHANNEL: Forever<Channel<NoopRawMutex, LedState, 1>> = Forever::new();
+static CHANNEL: StaticCell<Channel<NoopRawMutex, LedState, 1>> = StaticCell::new();
 
 #[embassy_executor::task]
 async fn send_task(sender: Sender<'static, NoopRawMutex, LedState, 1>) {
@@ -43,7 +43,7 @@ async fn recv_task(led: AnyPin, receiver: Receiver<'static, NoopRawMutex, LedSta
 #[embassy_executor::main]
 async fn main(spawner: Spawner) {
     let p = embassy_nrf::init(Default::default());
-    let channel = CHANNEL.put(Channel::new());
+    let channel = CHANNEL.init(Channel::new());
 
     unwrap!(spawner.spawn(send_task(channel.sender())));
     unwrap!(spawner.spawn(recv_task(p.P0_13.degrade(), channel.receiver())));
diff --git a/examples/nrf/src/bin/multiprio.rs b/examples/nrf/src/bin/multiprio.rs
index b653689a7..25806ae48 100644
--- a/examples/nrf/src/bin/multiprio.rs
+++ b/examples/nrf/src/bin/multiprio.rs
@@ -63,7 +63,7 @@ use embassy_nrf::executor::{Executor, InterruptExecutor};
 use embassy_nrf::interrupt;
 use embassy_nrf::interrupt::InterruptExt;
 use embassy_time::{Duration, Instant, Timer};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -108,9 +108,9 @@ async fn run_low() {
     }
 }
 
-static EXECUTOR_HIGH: Forever<InterruptExecutor<interrupt::SWI1_EGU1>> = Forever::new();
-static EXECUTOR_MED: Forever<InterruptExecutor<interrupt::SWI0_EGU0>> = Forever::new();
-static EXECUTOR_LOW: Forever<Executor> = Forever::new();
+static EXECUTOR_HIGH: StaticCell<InterruptExecutor<interrupt::SWI1_EGU1>> = StaticCell::new();
+static EXECUTOR_MED: StaticCell<InterruptExecutor<interrupt::SWI0_EGU0>> = StaticCell::new();
+static EXECUTOR_LOW: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
@@ -121,19 +121,19 @@ fn main() -> ! {
     // High-priority executor: SWI1_EGU1, priority level 6
     let irq = interrupt::take!(SWI1_EGU1);
     irq.set_priority(interrupt::Priority::P6);
-    let executor = EXECUTOR_HIGH.put(InterruptExecutor::new(irq));
+    let executor = EXECUTOR_HIGH.init(InterruptExecutor::new(irq));
     let spawner = executor.start();
     unwrap!(spawner.spawn(run_high()));
 
     // Medium-priority executor: SWI0_EGU0, priority level 7
     let irq = interrupt::take!(SWI0_EGU0);
     irq.set_priority(interrupt::Priority::P7);
-    let executor = EXECUTOR_MED.put(InterruptExecutor::new(irq));
+    let executor = EXECUTOR_MED.init(InterruptExecutor::new(irq));
     let spawner = executor.start();
     unwrap!(spawner.spawn(run_med()));
 
     // Low priority executor: runs in thread mode, using WFE/SEV
-    let executor = EXECUTOR_LOW.put(Executor::new());
+    let executor = EXECUTOR_LOW.init(Executor::new());
     executor.run(|spawner| {
         unwrap!(spawner.spawn(run_low()));
     });
diff --git a/examples/nrf/src/bin/mutex.rs b/examples/nrf/src/bin/mutex.rs
index 876297883..c402c6ba1 100644
--- a/examples/nrf/src/bin/mutex.rs
+++ b/examples/nrf/src/bin/mutex.rs
@@ -4,9 +4,9 @@
 
 use defmt::{info, unwrap};
 use embassy_executor::Spawner;
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::mutex::Mutex;
 use embassy_time::{Duration, Timer};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::mutex::Mutex;
 use {defmt_rtt as _, panic_probe as _};
 
 static MUTEX: Mutex<ThreadModeRawMutex, u32> = Mutex::new(0);
diff --git a/examples/nrf/src/bin/pubsub.rs b/examples/nrf/src/bin/pubsub.rs
index 1d90217f2..688e6d075 100644
--- a/examples/nrf/src/bin/pubsub.rs
+++ b/examples/nrf/src/bin/pubsub.rs
@@ -4,9 +4,9 @@
 
 use defmt::unwrap;
 use embassy_executor::Spawner;
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::pubsub::{DynSubscriber, PubSubChannel, Subscriber};
 use embassy_time::{Duration, Timer};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::pubsub::{DynSubscriber, PubSubChannel, Subscriber};
 use {defmt_rtt as _, panic_probe as _};
 
 /// Create the message bus. It has a queue of 4, supports 3 subscribers and 1 publisher
diff --git a/examples/nrf/src/bin/raw_spawn.rs b/examples/nrf/src/bin/raw_spawn.rs
index 415579be7..1b067f5e4 100644
--- a/examples/nrf/src/bin/raw_spawn.rs
+++ b/examples/nrf/src/bin/raw_spawn.rs
@@ -8,7 +8,7 @@ use defmt::{info, unwrap};
 use embassy_executor::raw::TaskStorage;
 use embassy_executor::Executor;
 use embassy_time::{Duration, Timer};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 async fn run1() {
@@ -25,14 +25,14 @@ async fn run2() {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
     info!("Hello World!");
 
     let _p = embassy_nrf::init(Default::default());
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
 
     let run1_task = TaskStorage::new();
     let run2_task = TaskStorage::new();
diff --git a/examples/nrf/src/bin/uart_split.rs b/examples/nrf/src/bin/uart_split.rs
index dab8e475d..1adaf53fd 100644
--- a/examples/nrf/src/bin/uart_split.rs
+++ b/examples/nrf/src/bin/uart_split.rs
@@ -7,8 +7,8 @@ use embassy_executor::Spawner;
 use embassy_nrf::peripherals::UARTE0;
 use embassy_nrf::uarte::UarteRx;
 use embassy_nrf::{interrupt, uarte};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::mpmc::Channel;
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
 use {defmt_rtt as _, panic_probe as _};
 
 static CHANNEL: Channel<ThreadModeRawMutex, [u8; 8], 1> = Channel::new();
diff --git a/examples/nrf/src/bin/usb_ethernet.rs b/examples/nrf/src/bin/usb_ethernet.rs
index f0a870317..ca6c7e0d1 100644
--- a/examples/nrf/src/bin/usb_ethernet.rs
+++ b/examples/nrf/src/bin/usb_ethernet.rs
@@ -14,21 +14,21 @@ use embassy_net::{PacketBox, PacketBoxExt, PacketBuf, Stack, StackResources};
 use embassy_nrf::rng::Rng;
 use embassy_nrf::usb::{Driver, PowerUsb};
 use embassy_nrf::{interrupt, pac, peripherals};
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
 use embassy_usb::{Builder, Config, UsbDevice};
 use embassy_usb_ncm::{CdcNcmClass, Receiver, Sender, State};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::mpmc::Channel;
-use embassy_util::Forever;
 use embedded_io::asynch::{Read, Write};
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 type MyDriver = Driver<'static, peripherals::USBD, PowerUsb>;
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -116,7 +116,7 @@ async fn main(spawner: Spawner) {
         control_buf: [u8; 128],
         serial_state: State<'static>,
     }
-    let res: &mut Resources = forever!(Resources {
+    let res: &mut Resources = singleton!(Resources {
         device_descriptor: [0; 256],
         config_descriptor: [0; 256],
         bos_descriptor: [0; 256],
@@ -174,10 +174,10 @@ async fn main(spawner: Spawner) {
 
     // Init network stack
     let device = Device { mac_addr: our_mac_addr };
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
diff --git a/examples/nrf/src/bin/usb_hid_keyboard.rs b/examples/nrf/src/bin/usb_hid_keyboard.rs
index cf0078eec..ba2159c72 100644
--- a/examples/nrf/src/bin/usb_hid_keyboard.rs
+++ b/examples/nrf/src/bin/usb_hid_keyboard.rs
@@ -8,14 +8,14 @@ use core::sync::atomic::{AtomicBool, Ordering};
 
 use defmt::*;
 use embassy_executor::Spawner;
+use embassy_futures::{select, Either};
 use embassy_nrf::gpio::{Input, Pin, Pull};
 use embassy_nrf::usb::{Driver, PowerUsb};
 use embassy_nrf::{interrupt, pac};
+use embassy_sync::signal::Signal;
 use embassy_usb::control::OutResponse;
 use embassy_usb::{Builder, Config, DeviceStateHandler};
 use embassy_usb_hid::{HidReaderWriter, ReportId, RequestHandler, State};
-use embassy_util::channel::signal::Signal;
-use embassy_util::{select, Either};
 use futures::future::join;
 use usbd_hid::descriptor::{KeyboardReport, SerializedDescriptor};
 use {defmt_rtt as _, panic_probe as _};
diff --git a/examples/nrf/src/bin/usb_serial_multitask.rs b/examples/nrf/src/bin/usb_serial_multitask.rs
index 4c1a93087..d62d7e520 100644
--- a/examples/nrf/src/bin/usb_serial_multitask.rs
+++ b/examples/nrf/src/bin/usb_serial_multitask.rs
@@ -12,7 +12,7 @@ use embassy_nrf::{interrupt, pac, peripherals};
 use embassy_usb::driver::EndpointError;
 use embassy_usb::{Builder, Config, UsbDevice};
 use embassy_usb_serial::{CdcAcmClass, State};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 type MyDriver = Driver<'static, peripherals::USBD, PowerUsb>;
@@ -67,8 +67,8 @@ async fn main(spawner: Spawner) {
         control_buf: [u8; 64],
         serial_state: State<'static>,
     }
-    static RESOURCES: Forever<Resources> = Forever::new();
-    let res = RESOURCES.put(Resources {
+    static RESOURCES: StaticCell<Resources> = StaticCell::new();
+    let res = RESOURCES.init(Resources {
         device_descriptor: [0; 256],
         config_descriptor: [0; 256],
         bos_descriptor: [0; 256],
diff --git a/examples/rp/Cargo.toml b/examples/rp/Cargo.toml
index c2dcf429a..d804a660b 100644
--- a/examples/rp/Cargo.toml
+++ b/examples/rp/Cargo.toml
@@ -5,7 +5,7 @@ version = "0.1.0"
 
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime"] }
 embassy-rp = { version = "0.1.0", path = "../../embassy-rp", features = ["defmt", "unstable-traits", "nightly", "unstable-pac"] }
diff --git a/examples/std/Cargo.toml b/examples/std/Cargo.toml
index b7009017c..c7cec6b19 100644
--- a/examples/std/Cargo.toml
+++ b/examples/std/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-std-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["log"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["log"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["log", "std", "nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["log", "std", "nightly"] }
 embassy-net = { version = "0.1.0", path = "../../embassy-net", features=[ "std", "log", "medium-ethernet", "tcp", "udp", "dhcpv4", "pool-16"] }
@@ -20,3 +20,4 @@ libc = "0.2.101"
 clap = { version = "3.0.0-beta.5", features = ["derive"] }
 rand_core = { version = "0.6.3", features = ["std"] }
 heapless = { version = "0.7.5", default-features = false }
+static_cell = "1.0"
diff --git a/examples/std/src/bin/net.rs b/examples/std/src/bin/net.rs
index 528609260..9b1450b72 100644
--- a/examples/std/src/bin/net.rs
+++ b/examples/std/src/bin/net.rs
@@ -4,22 +4,22 @@ use clap::Parser;
 use embassy_executor::{Executor, Spawner};
 use embassy_net::tcp::TcpSocket;
 use embassy_net::{ConfigStrategy, Ipv4Address, Ipv4Cidr, Stack, StackResources};
-use embassy_util::Forever;
 use embedded_io::asynch::Write;
 use heapless::Vec;
 use log::*;
 use rand_core::{OsRng, RngCore};
+use static_cell::StaticCell;
 
 #[path = "../tuntap.rs"]
 mod tuntap;
 
 use crate::tuntap::TunTapDevice;
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -63,10 +63,10 @@ async fn main_task(spawner: Spawner) {
     let seed = u64::from_le_bytes(seed);
 
     // Init network stack
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
@@ -97,7 +97,7 @@ async fn main_task(spawner: Spawner) {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 fn main() {
     env_logger::builder()
@@ -106,7 +106,7 @@ fn main() {
         .format_timestamp_nanos()
         .init();
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
     executor.run(|spawner| {
         spawner.spawn(main_task(spawner)).unwrap();
     });
diff --git a/examples/std/src/bin/net_udp.rs b/examples/std/src/bin/net_udp.rs
index 07e11c385..392a97f0d 100644
--- a/examples/std/src/bin/net_udp.rs
+++ b/examples/std/src/bin/net_udp.rs
@@ -4,21 +4,21 @@ use clap::Parser;
 use embassy_executor::{Executor, Spawner};
 use embassy_net::udp::UdpSocket;
 use embassy_net::{ConfigStrategy, Ipv4Address, Ipv4Cidr, PacketMetadata, Stack, StackResources};
-use embassy_util::Forever;
 use heapless::Vec;
 use log::*;
 use rand_core::{OsRng, RngCore};
+use static_cell::StaticCell;
 
 #[path = "../tuntap.rs"]
 mod tuntap;
 
 use crate::tuntap::TunTapDevice;
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -62,10 +62,10 @@ async fn main_task(spawner: Spawner) {
     let seed = u64::from_le_bytes(seed);
 
     // Init network stack
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
@@ -93,7 +93,7 @@ async fn main_task(spawner: Spawner) {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 fn main() {
     env_logger::builder()
@@ -102,7 +102,7 @@ fn main() {
         .format_timestamp_nanos()
         .init();
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
     executor.run(|spawner| {
         spawner.spawn(main_task(spawner)).unwrap();
     });
diff --git a/examples/std/src/bin/serial.rs b/examples/std/src/bin/serial.rs
index 35cba4cee..85ee54f70 100644
--- a/examples/std/src/bin/serial.rs
+++ b/examples/std/src/bin/serial.rs
@@ -5,10 +5,10 @@ mod serial_port;
 
 use async_io::Async;
 use embassy_executor::Executor;
-use embassy_util::Forever;
 use embedded_io::asynch::Read;
 use log::*;
 use nix::sys::termios;
+use static_cell::StaticCell;
 
 use self::serial_port::SerialPort;
 
@@ -40,7 +40,7 @@ async fn run() {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 fn main() {
     env_logger::builder()
@@ -49,7 +49,7 @@ fn main() {
         .format_timestamp_nanos()
         .init();
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
     executor.run(|spawner| {
         spawner.spawn(run()).unwrap();
     });
diff --git a/examples/stm32f0/Cargo.toml b/examples/stm32f0/Cargo.toml
index 8476200d4..cd2995d2c 100644
--- a/examples/stm32f0/Cargo.toml
+++ b/examples/stm32f0/Cargo.toml
@@ -11,7 +11,7 @@ cortex-m-rt = "0.7.0"
 defmt = "0.3"
 defmt-rtt = "0.3"
 panic-probe = "0.3"
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "memory-x", "stm32f030f4", "time-driver-any"] }
diff --git a/examples/stm32f1/Cargo.toml b/examples/stm32f1/Cargo.toml
index fbc96400c..8660e743d 100644
--- a/examples/stm32f1/Cargo.toml
+++ b/examples/stm32f1/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32f1-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32f103c8", "unstable-pac", "memory-x", "time-driver-any"]  }
diff --git a/examples/stm32f2/Cargo.toml b/examples/stm32f2/Cargo.toml
index 27894df50..b4bff4d85 100644
--- a/examples/stm32f2/Cargo.toml
+++ b/examples/stm32f2/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32f2-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32f207zg", "unstable-pac", "memory-x", "time-driver-any", "exti"]  }
diff --git a/examples/stm32f3/Cargo.toml b/examples/stm32f3/Cargo.toml
index b5ea28bb6..d152b145f 100644
--- a/examples/stm32f3/Cargo.toml
+++ b/examples/stm32f3/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32f3-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32f303ze", "unstable-pac", "memory-x", "time-driver-any", "exti"]  }
@@ -23,3 +23,4 @@ futures = { version = "0.3.17", default-features = false, features = ["async-awa
 heapless = { version = "0.7.5", default-features = false }
 nb = "1.0.0"
 embedded-storage = "0.3.0"
+static_cell = "1.0"
diff --git a/examples/stm32f3/src/bin/button_events.rs b/examples/stm32f3/src/bin/button_events.rs
index 61fc6dcab..02c475f66 100644
--- a/examples/stm32f3/src/bin/button_events.rs
+++ b/examples/stm32f3/src/bin/button_events.rs
@@ -15,9 +15,9 @@ use embassy_executor::Spawner;
 use embassy_stm32::exti::ExtiInput;
 use embassy_stm32::gpio::{AnyPin, Input, Level, Output, Pin, Pull, Speed};
 use embassy_stm32::peripherals::PA0;
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
 use embassy_time::{with_timeout, Duration, Timer};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::mpmc::Channel;
 use {defmt_rtt as _, panic_probe as _};
 
 struct Leds<'a> {
diff --git a/examples/stm32f3/src/bin/multiprio.rs b/examples/stm32f3/src/bin/multiprio.rs
index e96c31249..9e8228a4b 100644
--- a/examples/stm32f3/src/bin/multiprio.rs
+++ b/examples/stm32f3/src/bin/multiprio.rs
@@ -63,7 +63,7 @@ use embassy_stm32::executor::{Executor, InterruptExecutor};
 use embassy_stm32::interrupt;
 use embassy_stm32::interrupt::InterruptExt;
 use embassy_time::{Duration, Instant, Timer};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -108,9 +108,9 @@ async fn run_low() {
     }
 }
 
-static EXECUTOR_HIGH: Forever<InterruptExecutor<interrupt::UART4>> = Forever::new();
-static EXECUTOR_MED: Forever<InterruptExecutor<interrupt::UART5>> = Forever::new();
-static EXECUTOR_LOW: Forever<Executor> = Forever::new();
+static EXECUTOR_HIGH: StaticCell<InterruptExecutor<interrupt::UART4>> = StaticCell::new();
+static EXECUTOR_MED: StaticCell<InterruptExecutor<interrupt::UART5>> = StaticCell::new();
+static EXECUTOR_LOW: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
@@ -121,19 +121,19 @@ fn main() -> ! {
     // High-priority executor: SWI1_EGU1, priority level 6
     let irq = interrupt::take!(UART4);
     irq.set_priority(interrupt::Priority::P6);
-    let executor = EXECUTOR_HIGH.put(InterruptExecutor::new(irq));
+    let executor = EXECUTOR_HIGH.init(InterruptExecutor::new(irq));
     let spawner = executor.start();
     unwrap!(spawner.spawn(run_high()));
 
     // Medium-priority executor: SWI0_EGU0, priority level 7
     let irq = interrupt::take!(UART5);
     irq.set_priority(interrupt::Priority::P7);
-    let executor = EXECUTOR_MED.put(InterruptExecutor::new(irq));
+    let executor = EXECUTOR_MED.init(InterruptExecutor::new(irq));
     let spawner = executor.start();
     unwrap!(spawner.spawn(run_med()));
 
     // Low priority executor: runs in thread mode, using WFE/SEV
-    let executor = EXECUTOR_LOW.put(Executor::new());
+    let executor = EXECUTOR_LOW.init(Executor::new());
     executor.run(|spawner| {
         unwrap!(spawner.spawn(run_low()));
     });
diff --git a/examples/stm32f4/Cargo.toml b/examples/stm32f4/Cargo.toml
index 04a217aff..9bfdda92d 100644
--- a/examples/stm32f4/Cargo.toml
+++ b/examples/stm32f4/Cargo.toml
@@ -5,7 +5,7 @@ version = "0.1.0"
 
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "unstable-traits", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "unstable-traits", "defmt", "stm32f429zi", "unstable-pac", "memory-x", "time-driver-any", "exti"]  }
@@ -23,6 +23,7 @@ heapless = { version = "0.7.5", default-features = false }
 nb = "1.0.0"
 embedded-storage = "0.3.0"
 micromath = "2.0.0"
+static_cell = "1.0"
 
 usb-device = "0.2"
 usbd-serial = "0.1.1"
diff --git a/examples/stm32f4/src/bin/multiprio.rs b/examples/stm32f4/src/bin/multiprio.rs
index e96c31249..9e8228a4b 100644
--- a/examples/stm32f4/src/bin/multiprio.rs
+++ b/examples/stm32f4/src/bin/multiprio.rs
@@ -63,7 +63,7 @@ use embassy_stm32::executor::{Executor, InterruptExecutor};
 use embassy_stm32::interrupt;
 use embassy_stm32::interrupt::InterruptExt;
 use embassy_time::{Duration, Instant, Timer};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -108,9 +108,9 @@ async fn run_low() {
     }
 }
 
-static EXECUTOR_HIGH: Forever<InterruptExecutor<interrupt::UART4>> = Forever::new();
-static EXECUTOR_MED: Forever<InterruptExecutor<interrupt::UART5>> = Forever::new();
-static EXECUTOR_LOW: Forever<Executor> = Forever::new();
+static EXECUTOR_HIGH: StaticCell<InterruptExecutor<interrupt::UART4>> = StaticCell::new();
+static EXECUTOR_MED: StaticCell<InterruptExecutor<interrupt::UART5>> = StaticCell::new();
+static EXECUTOR_LOW: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
@@ -121,19 +121,19 @@ fn main() -> ! {
     // High-priority executor: SWI1_EGU1, priority level 6
     let irq = interrupt::take!(UART4);
     irq.set_priority(interrupt::Priority::P6);
-    let executor = EXECUTOR_HIGH.put(InterruptExecutor::new(irq));
+    let executor = EXECUTOR_HIGH.init(InterruptExecutor::new(irq));
     let spawner = executor.start();
     unwrap!(spawner.spawn(run_high()));
 
     // Medium-priority executor: SWI0_EGU0, priority level 7
     let irq = interrupt::take!(UART5);
     irq.set_priority(interrupt::Priority::P7);
-    let executor = EXECUTOR_MED.put(InterruptExecutor::new(irq));
+    let executor = EXECUTOR_MED.init(InterruptExecutor::new(irq));
     let spawner = executor.start();
     unwrap!(spawner.spawn(run_med()));
 
     // Low priority executor: runs in thread mode, using WFE/SEV
-    let executor = EXECUTOR_LOW.put(Executor::new());
+    let executor = EXECUTOR_LOW.init(Executor::new());
     executor.run(|spawner| {
         unwrap!(spawner.spawn(run_low()));
     });
diff --git a/examples/stm32f7/Cargo.toml b/examples/stm32f7/Cargo.toml
index 29d6da4d8..a446fe3fb 100644
--- a/examples/stm32f7/Cargo.toml
+++ b/examples/stm32f7/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32f7-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "net", "stm32f767zi", "unstable-pac", "time-driver-any", "exti"]  }
@@ -24,3 +24,4 @@ nb = "1.0.0"
 rand_core = "0.6.3"
 critical-section = "1.1"
 embedded-storage = "0.3.0"
+static_cell = "1.0"
diff --git a/examples/stm32f7/src/bin/eth.rs b/examples/stm32f7/src/bin/eth.rs
index bdffabcb3..5202edf62 100644
--- a/examples/stm32f7/src/bin/eth.rs
+++ b/examples/stm32f7/src/bin/eth.rs
@@ -13,16 +13,16 @@ use embassy_stm32::rng::Rng;
 use embassy_stm32::time::mhz;
 use embassy_stm32::{interrupt, Config};
 use embassy_time::{Duration, Timer};
-use embassy_util::Forever;
 use embedded_io::asynch::Write;
 use rand_core::RngCore;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -52,7 +52,7 @@ async fn main(spawner: Spawner) -> ! {
 
     let device = unsafe {
         Ethernet::new(
-            forever!(State::new()),
+            singleton!(State::new()),
             p.ETH,
             eth_int,
             p.PA1,
@@ -78,10 +78,10 @@ async fn main(spawner: Spawner) -> ! {
     //});
 
     // Init network stack
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
diff --git a/examples/stm32g0/Cargo.toml b/examples/stm32g0/Cargo.toml
index 5c80d43eb..30f2b86f8 100644
--- a/examples/stm32g0/Cargo.toml
+++ b/examples/stm32g0/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32g0-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "time-driver-any", "stm32g071rb", "memory-x", "unstable-pac", "exti"]  }
diff --git a/examples/stm32g4/Cargo.toml b/examples/stm32g4/Cargo.toml
index 74c645cf5..f81df0b70 100644
--- a/examples/stm32g4/Cargo.toml
+++ b/examples/stm32g4/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32g4-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "time-driver-any", "stm32g491re", "memory-x", "unstable-pac", "exti"]  }
diff --git a/examples/stm32h7/Cargo.toml b/examples/stm32h7/Cargo.toml
index a416796ea..0f76f3226 100644
--- a/examples/stm32h7/Cargo.toml
+++ b/examples/stm32h7/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32h7-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "unstable-traits", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32h743bi", "net", "time-driver-any", "exti", "unstable-pac", "unstable-traits"] }
@@ -28,6 +28,7 @@ critical-section = "1.1"
 micromath = "2.0.0"
 stm32-fmc = "0.2.4"
 embedded-storage = "0.3.0"
+static_cell = "1.0"
 
 # cargo build/run
 [profile.dev]
diff --git a/examples/stm32h7/src/bin/eth.rs b/examples/stm32h7/src/bin/eth.rs
index 83210bcb5..4ccc0b5ef 100644
--- a/examples/stm32h7/src/bin/eth.rs
+++ b/examples/stm32h7/src/bin/eth.rs
@@ -13,16 +13,16 @@ use embassy_stm32::rng::Rng;
 use embassy_stm32::time::mhz;
 use embassy_stm32::{interrupt, Config};
 use embassy_time::{Duration, Timer};
-use embassy_util::Forever;
 use embedded_io::asynch::Write;
 use rand_core::RngCore;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -53,7 +53,7 @@ async fn main(spawner: Spawner) -> ! {
 
     let device = unsafe {
         Ethernet::new(
-            forever!(State::new()),
+            singleton!(State::new()),
             p.ETH,
             eth_int,
             p.PA1,
@@ -79,10 +79,10 @@ async fn main(spawner: Spawner) -> ! {
     //});
 
     // Init network stack
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
diff --git a/examples/stm32h7/src/bin/eth_client.rs b/examples/stm32h7/src/bin/eth_client.rs
index 99946f504..64fd84141 100644
--- a/examples/stm32h7/src/bin/eth_client.rs
+++ b/examples/stm32h7/src/bin/eth_client.rs
@@ -13,17 +13,17 @@ use embassy_stm32::rng::Rng;
 use embassy_stm32::time::mhz;
 use embassy_stm32::{interrupt, Config};
 use embassy_time::{Duration, Timer};
-use embassy_util::Forever;
 use embedded_io::asynch::Write;
 use embedded_nal_async::{Ipv4Addr, SocketAddr, SocketAddrV4, TcpConnect};
 use rand_core::RngCore;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -54,7 +54,7 @@ async fn main(spawner: Spawner) -> ! {
 
     let device = unsafe {
         Ethernet::new(
-            forever!(State::new()),
+            singleton!(State::new()),
             p.ETH,
             eth_int,
             p.PA1,
@@ -80,10 +80,10 @@ async fn main(spawner: Spawner) -> ! {
     //});
 
     // Init network stack
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
diff --git a/examples/stm32h7/src/bin/signal.rs b/examples/stm32h7/src/bin/signal.rs
index be2ac268e..cc3e4e3ca 100644
--- a/examples/stm32h7/src/bin/signal.rs
+++ b/examples/stm32h7/src/bin/signal.rs
@@ -4,8 +4,8 @@
 
 use defmt::{info, unwrap};
 use embassy_executor::Spawner;
+use embassy_sync::signal::Signal;
 use embassy_time::{Duration, Timer};
-use embassy_util::channel::signal::Signal;
 use {defmt_rtt as _, panic_probe as _};
 
 static SIGNAL: Signal<u32> = Signal::new();
diff --git a/examples/stm32h7/src/bin/spi.rs b/examples/stm32h7/src/bin/spi.rs
index c28f937a8..1f407f002 100644
--- a/examples/stm32h7/src/bin/spi.rs
+++ b/examples/stm32h7/src/bin/spi.rs
@@ -12,8 +12,8 @@ use embassy_stm32::dma::NoDma;
 use embassy_stm32::peripherals::SPI3;
 use embassy_stm32::time::mhz;
 use embassy_stm32::{spi, Config};
-use embassy_util::Forever;
 use heapless::String;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -31,7 +31,7 @@ async fn main_task(mut spi: spi::Spi<'static, SPI3, NoDma, NoDma>) {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
@@ -54,7 +54,7 @@ fn main() -> ! {
         spi::Config::default(),
     );
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
 
     executor.run(|spawner| {
         unwrap!(spawner.spawn(main_task(spi)));
diff --git a/examples/stm32h7/src/bin/spi_dma.rs b/examples/stm32h7/src/bin/spi_dma.rs
index 6c78c194f..53004fc9b 100644
--- a/examples/stm32h7/src/bin/spi_dma.rs
+++ b/examples/stm32h7/src/bin/spi_dma.rs
@@ -11,8 +11,8 @@ use embassy_executor::Executor;
 use embassy_stm32::peripherals::{DMA1_CH3, DMA1_CH4, SPI3};
 use embassy_stm32::time::mhz;
 use embassy_stm32::{spi, Config};
-use embassy_util::Forever;
 use heapless::String;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -27,7 +27,7 @@ async fn main_task(mut spi: spi::Spi<'static, SPI3, DMA1_CH3, DMA1_CH4>) {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
@@ -50,7 +50,7 @@ fn main() -> ! {
         spi::Config::default(),
     );
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
 
     executor.run(|spawner| {
         unwrap!(spawner.spawn(main_task(spi)));
diff --git a/examples/stm32h7/src/bin/usart.rs b/examples/stm32h7/src/bin/usart.rs
index 1384d54c6..87c2b1253 100644
--- a/examples/stm32h7/src/bin/usart.rs
+++ b/examples/stm32h7/src/bin/usart.rs
@@ -7,7 +7,7 @@ use defmt::*;
 use embassy_executor::Executor;
 use embassy_stm32::dma::NoDma;
 use embassy_stm32::usart::{Config, Uart};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -27,13 +27,13 @@ async fn main_task() {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
     info!("Hello World!");
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
 
     executor.run(|spawner| {
         unwrap!(spawner.spawn(main_task()));
diff --git a/examples/stm32h7/src/bin/usart_dma.rs b/examples/stm32h7/src/bin/usart_dma.rs
index f8d58bb84..3adffcbeb 100644
--- a/examples/stm32h7/src/bin/usart_dma.rs
+++ b/examples/stm32h7/src/bin/usart_dma.rs
@@ -9,8 +9,8 @@ use defmt::*;
 use embassy_executor::Executor;
 use embassy_stm32::dma::NoDma;
 use embassy_stm32::usart::{Config, Uart};
-use embassy_util::Forever;
 use heapless::String;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
@@ -30,13 +30,13 @@ async fn main_task() {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
     info!("Hello World!");
 
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
 
     executor.run(|spawner| {
         unwrap!(spawner.spawn(main_task()));
diff --git a/examples/stm32h7/src/bin/usart_split.rs b/examples/stm32h7/src/bin/usart_split.rs
index 64080ec45..df2b600f8 100644
--- a/examples/stm32h7/src/bin/usart_split.rs
+++ b/examples/stm32h7/src/bin/usart_split.rs
@@ -7,8 +7,8 @@ use embassy_executor::Spawner;
 use embassy_stm32::dma::NoDma;
 use embassy_stm32::peripherals::{DMA1_CH1, UART7};
 use embassy_stm32::usart::{Config, Uart, UartRx};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::mpmc::Channel;
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::task]
diff --git a/examples/stm32l0/Cargo.toml b/examples/stm32l0/Cargo.toml
index fdb716d15..11751a21d 100644
--- a/examples/stm32l0/Cargo.toml
+++ b/examples/stm32l0/Cargo.toml
@@ -8,7 +8,7 @@ default = ["nightly"]
 nightly = ["embassy-stm32/nightly", "embassy-lora", "lorawan-device", "lorawan", "embedded-io/async"]
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["defmt", "stm32l072cz", "time-driver-any", "exti", "unstable-traits", "memory-x"]  }
@@ -29,3 +29,4 @@ panic-probe = { version = "0.3", features = ["print-defmt"] }
 futures = { version = "0.3.17", default-features = false, features = ["async-await"] }
 heapless = { version = "0.7.5", default-features = false }
 embedded-hal = "0.2.6"
+static_cell = "1.0"
diff --git a/examples/stm32l0/src/bin/raw_spawn.rs b/examples/stm32l0/src/bin/raw_spawn.rs
index bd87e62a4..edc17304a 100644
--- a/examples/stm32l0/src/bin/raw_spawn.rs
+++ b/examples/stm32l0/src/bin/raw_spawn.rs
@@ -8,7 +8,7 @@ use defmt::*;
 use embassy_executor::raw::TaskStorage;
 use embassy_executor::Executor;
 use embassy_time::{Duration, Timer};
-use embassy_util::Forever;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 async fn run1() {
@@ -25,14 +25,14 @@ async fn run2() {
     }
 }
 
-static EXECUTOR: Forever<Executor> = Forever::new();
+static EXECUTOR: StaticCell<Executor> = StaticCell::new();
 
 #[entry]
 fn main() -> ! {
     info!("Hello World!");
 
     let _p = embassy_stm32::init(Default::default());
-    let executor = EXECUTOR.put(Executor::new());
+    let executor = EXECUTOR.init(Executor::new());
 
     let run1_task = TaskStorage::new();
     let run2_task = TaskStorage::new();
diff --git a/examples/stm32l1/Cargo.toml b/examples/stm32l1/Cargo.toml
index 43f844b67..18b35b305 100644
--- a/examples/stm32l1/Cargo.toml
+++ b/examples/stm32l1/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32l1-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32l151cb-a", "time-driver-any", "memory-x"]  }
diff --git a/examples/stm32l4/Cargo.toml b/examples/stm32l4/Cargo.toml
index eaffa253e..cb7238e4c 100644
--- a/examples/stm32l4/Cargo.toml
+++ b/examples/stm32l4/Cargo.toml
@@ -6,7 +6,7 @@ version = "0.1.0"
 [features]
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-embedded-hal = { version = "0.1.0", path = "../../embassy-embedded-hal" }
diff --git a/examples/stm32l5/Cargo.toml b/examples/stm32l5/Cargo.toml
index 4d96d31fc..624c73c26 100644
--- a/examples/stm32l5/Cargo.toml
+++ b/examples/stm32l5/Cargo.toml
@@ -6,7 +6,7 @@ version = "0.1.0"
 [features]
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "unstable-pac", "stm32l552ze", "time-driver-any", "exti", "unstable-traits", "memory-x"]  }
@@ -28,3 +28,4 @@ futures = { version = "0.3.17", default-features = false, features = ["async-awa
 heapless = { version = "0.7.5", default-features = false }
 rand_core = { version = "0.6.3", default-features = false }
 embedded-io = { version = "0.3.0", features = ["async"] }
+static_cell = "1.0"
diff --git a/examples/stm32l5/src/bin/usb_ethernet.rs b/examples/stm32l5/src/bin/usb_ethernet.rs
index 7c53d03cc..3286f5c4d 100644
--- a/examples/stm32l5/src/bin/usb_ethernet.rs
+++ b/examples/stm32l5/src/bin/usb_ethernet.rs
@@ -15,22 +15,22 @@ use embassy_stm32::rng::Rng;
 use embassy_stm32::time::Hertz;
 use embassy_stm32::usb::Driver;
 use embassy_stm32::{interrupt, Config};
+use embassy_sync::blocking_mutex::raw::ThreadModeRawMutex;
+use embassy_sync::channel::Channel;
 use embassy_usb::{Builder, UsbDevice};
 use embassy_usb_ncm::{CdcNcmClass, Receiver, Sender, State};
-use embassy_util::blocking_mutex::raw::ThreadModeRawMutex;
-use embassy_util::channel::mpmc::Channel;
-use embassy_util::Forever;
 use embedded_io::asynch::{Read, Write};
 use rand_core::RngCore;
+use static_cell::StaticCell;
 use {defmt_rtt as _, panic_probe as _};
 
 type MyDriver = Driver<'static, embassy_stm32::peripherals::USB>;
 
-macro_rules! forever {
+macro_rules! singleton {
     ($val:expr) => {{
         type T = impl Sized;
-        static FOREVER: Forever<T> = Forever::new();
-        FOREVER.put_with(move || $val)
+        static STATIC_CELL: StaticCell<T> = StaticCell::new();
+        STATIC_CELL.init_with(move || $val)
     }};
 }
 
@@ -115,7 +115,7 @@ async fn main(spawner: Spawner) {
         control_buf: [u8; 128],
         serial_state: State<'static>,
     }
-    let res: &mut Resources = forever!(Resources {
+    let res: &mut Resources = singleton!(Resources {
         device_descriptor: [0; 256],
         config_descriptor: [0; 256],
         bos_descriptor: [0; 256],
@@ -171,10 +171,10 @@ async fn main(spawner: Spawner) {
 
     // Init network stack
     let device = Device { mac_addr: our_mac_addr };
-    let stack = &*forever!(Stack::new(
+    let stack = &*singleton!(Stack::new(
         device,
         config,
-        forever!(StackResources::<1, 2, 8>::new()),
+        singleton!(StackResources::<1, 2, 8>::new()),
         seed
     ));
 
diff --git a/examples/stm32u5/Cargo.toml b/examples/stm32u5/Cargo.toml
index 48833664a..ff0ec9f42 100644
--- a/examples/stm32u5/Cargo.toml
+++ b/examples/stm32u5/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32u5-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "unstable-pac", "stm32u585ai", "time-driver-any", "memory-x" ]  }
diff --git a/examples/stm32wb/Cargo.toml b/examples/stm32wb/Cargo.toml
index b46300764..3b10da0ad 100644
--- a/examples/stm32wb/Cargo.toml
+++ b/examples/stm32wb/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32wb-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32wb55cc", "time-driver-any", "exti"]  }
diff --git a/examples/stm32wl/Cargo.toml b/examples/stm32wl/Cargo.toml
index ae33478af..5f6679f4b 100644
--- a/examples/stm32wl/Cargo.toml
+++ b/examples/stm32wl/Cargo.toml
@@ -4,7 +4,7 @@ name = "embassy-stm32wl-examples"
 version = "0.1.0"
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["defmt"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["defmt"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["defmt", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["defmt", "defmt-timestamp-uptime", "tick-32768hz"] }
 embassy-stm32 = { version = "0.1.0", path = "../../embassy-stm32", features = ["nightly", "defmt", "stm32wl55jc-cm4", "time-driver-any", "memory-x", "subghz", "unstable-pac", "exti"]  }
diff --git a/examples/stm32wl/src/bin/subghz.rs b/examples/stm32wl/src/bin/subghz.rs
index d16e3f5e4..c5e9bb597 100644
--- a/examples/stm32wl/src/bin/subghz.rs
+++ b/examples/stm32wl/src/bin/subghz.rs
@@ -13,7 +13,7 @@ use embassy_stm32::gpio::{Input, Level, Output, Pull, Speed};
 use embassy_stm32::interrupt;
 use embassy_stm32::interrupt::{Interrupt, InterruptExt};
 use embassy_stm32::subghz::*;
-use embassy_util::channel::signal::Signal;
+use embassy_sync::signal::Signal;
 use {defmt_rtt as _, panic_probe as _};
 
 const PING_DATA: &str = "PING";
diff --git a/examples/wasm/Cargo.toml b/examples/wasm/Cargo.toml
index c7f980366..ea61fb921 100644
--- a/examples/wasm/Cargo.toml
+++ b/examples/wasm/Cargo.toml
@@ -7,7 +7,7 @@ version = "0.1.0"
 crate-type = ["cdylib"]
 
 [dependencies]
-embassy-util = { version = "0.1.0", path = "../../embassy-util", features = ["log"] }
+embassy-sync = { version = "0.1.0", path = "../../embassy-sync", features = ["log"] }
 embassy-executor = { version = "0.1.0", path = "../../embassy-executor", features = ["log", "wasm", "nightly", "integrated-timers"] }
 embassy-time = { version = "0.1.0", path = "../../embassy-time", features = ["log", "wasm", "nightly"] }
 
@@ -15,4 +15,4 @@ wasm-logger = "0.2.0"
 wasm-bindgen = "0.2"
 web-sys = { version = "0.3", features = ["Document", "Element", "HtmlElement", "Node", "Window" ] }
 log = "0.4.11"
-critical-section = "1.1"
+critical-section = { version = "1.1", features = ["std"] }
diff --git a/examples/wasm/README.md b/examples/wasm/README.md
index 4bed4a797..b7fee2dc8 100644
--- a/examples/wasm/README.md
+++ b/examples/wasm/README.md
@@ -3,7 +3,7 @@
 Examples use a CLI tool named `wasm-pack` to build this example:
 
 ```
-cargo install wasm-pack
+cargo install wasm-pack --version 0.9.1
 ```
 
 ## Building