Merge branch 'main' of https://github.com/embassy-rs/embassy into mac

.gitattributes

@@ -0,0 +1,41 @@
+* text=auto
+
+*.adoc     text
+*.html     text
+*.in       text
+*.json     text
+*.md       text
+*.proto    text
+*.py       text
+*.rs       text
+*.service  text
+*.sh       text
+*.toml     text
+*.txt      text
+*.x        text
+*.yml      text
+
+*.raw    binary
+*.bin    binary
+*.png    binary
+*.jpg    binary
+*.jpeg   binary
+*.gif    binary
+*.ico    binary
+*.mov    binary
+*.mp4    binary
+*.mp3    binary
+*.flv    binary
+*.fla    binary
+*.swf    binary
+*.gz     binary
+*.zip    binary
+*.7z     binary
+*.ttf    binary
+*.eot    binary
+*.woff   binary
+*.pyc    binary
+*.pdf    binary
+*.ez     binary
+*.bz2    binary
+*.swp    binary

.github/ci/crlf.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+## on push branch~=gh-readonly-queue/main/.*
+## on pull_request
+
+set -euo pipefail
+
+FILES_WITH_CRLF=$(find  ! -path "./.git/*" -not -type d | xargs file -N | (grep " CRLF " || true))
+
+if [ -z "$FILES_WITH_CRLF" ]; then
+  echo -e "No files with CRLF endings found."
+  exit 0
+else
+  NR_FILES=$(echo "$FILES_WITH_CRLF" | wc -l)
+  echo -e "ERROR: Found ${NR_FILES} files with CRLF endings."
+  echo "$FILES_WITH_CRLF"
+  exit "$NR_FILES"
+fi

.github/ci/doc.sh

@@ -37,6 +37,7 @@ docserver-builder -i ./embassy-usb-logger -o webroot/crates/embassy-usb-logger/g
 docserver-builder -i ./cyw43 -o webroot/crates/cyw43/git.zup
 docserver-builder -i ./cyw43-pio -o webroot/crates/cyw43-pio/git.zup
 docserver-builder -i ./embassy-net-w5500 -o webroot/crates/embassy-net-w5500/git.zup
+docserver-builder -i ./embassy-net-esp-hosted -o webroot/crates/embassy-net-esp-hosted/git.zup
 docserver-builder -i ./embassy-stm32-wpan -o webroot/crates/embassy-stm32-wpan/git.zup --output-static webroot/static
 
 export KUBECONFIG=/ci/secrets/kubeconfig.yml

embassy-net-esp-hosted/Cargo.toml

@@ -18,3 +18,9 @@ embedded-hal-async = { version = "=0.2.0-alpha.2" }
 noproto = { git="https://github.com/embassy-rs/noproto", default-features = false, features = ["derive"] }
 #noproto = { version = "0.1", path = "/home/dirbaio/noproto", default-features = false, features = ["derive"] }
 heapless = "0.7.16"
+
+[package.metadata.embassy_docs]
+src_base = "https://github.com/embassy-rs/embassy/blob/embassy-net-esp-hosted-v$VERSION/embassy-net-esp-hosted/src/"
+src_base_git = "https://github.com/embassy-rs/embassy/blob/$COMMIT/embassy-net-esp-hosted/src/"
+target = "thumbv7em-none-eabi"
+features = ["defmt"]

embassy-net/src/lib.rs

@@ -490,30 +490,78 @@ impl<D: Driver + 'static> Stack<D> {
 }
 
 #[cfg(feature = "igmp")]
-impl<D: Driver + smoltcp::phy::Device + 'static> Stack<D> {
+impl<D: Driver + 'static> Stack<D> {
     /// Join a multicast group.
-    pub fn join_multicast_group<T>(&self, addr: T) -> Result<bool, MulticastError>
+    pub async fn join_multicast_group<T>(&self, addr: T) -> Result<bool, MulticastError>
+    where
+        T: Into<IpAddress>,
+    {
+        let addr = addr.into();
+
+        poll_fn(move |cx| self.poll_join_multicast_group(addr, cx)).await
+    }
+
+    /// Join a multicast group.
+    ///
+    /// When the send queue is full, this method will return `Poll::Pending`
+    /// and register the current task to be notified when the queue has space available.
+    pub fn poll_join_multicast_group<T>(&self, addr: T, cx: &mut Context<'_>) -> Poll<Result<bool, MulticastError>>
     where
         T: Into<IpAddress>,
     {
         let addr = addr.into();
 
         self.with_mut(|s, i| {
-            s.iface
+            let mut smoldev = DriverAdapter {
-                .join_multicast_group(&mut i.device, addr, instant_to_smoltcp(Instant::now()))
+                cx: Some(cx),
+                inner: &mut i.device,
+            };
+
+            match s
+                .iface
+                .join_multicast_group(&mut smoldev, addr, instant_to_smoltcp(Instant::now()))
+            {
+                Ok(announce_sent) => Poll::Ready(Ok(announce_sent)),
+                Err(MulticastError::Exhausted) => Poll::Pending,
+                Err(other) => Poll::Ready(Err(other)),
+            }
         })
     }
 
     /// Leave a multicast group.
-    pub fn leave_multicast_group<T>(&self, addr: T) -> Result<bool, MulticastError>
+    pub async fn leave_multicast_group<T>(&self, addr: T) -> Result<bool, MulticastError>
+    where
+        T: Into<IpAddress>,
+    {
+        let addr = addr.into();
+
+        poll_fn(move |cx| self.poll_leave_multicast_group(addr, cx)).await
+    }
+
+    /// Leave a multicast group.
+    ///
+    /// When the send queue is full, this method will return `Poll::Pending`
+    /// and register the current task to be notified when the queue has space available.
+    pub fn poll_leave_multicast_group<T>(&self, addr: T, cx: &mut Context<'_>) -> Poll<Result<bool, MulticastError>>
     where
         T: Into<IpAddress>,
     {
         let addr = addr.into();
 
         self.with_mut(|s, i| {
-            s.iface
+            let mut smoldev = DriverAdapter {
-                .leave_multicast_group(&mut i.device, addr, instant_to_smoltcp(Instant::now()))
+                cx: Some(cx),
+                inner: &mut i.device,
+            };
+
+            match s
+                .iface
+                .leave_multicast_group(&mut smoldev, addr, instant_to_smoltcp(Instant::now()))
+            {
+                Ok(leave_sent) => Poll::Ready(Ok(leave_sent)),
+                Err(MulticastError::Exhausted) => Poll::Pending,
+                Err(other) => Poll::Ready(Err(other)),
+            }
         })
     }
 
@@ -542,11 +590,14 @@ impl<D: Driver + 'static> Inner<D> {
 
         debug!("   IP address:      {}", config.address);
         s.iface.update_ip_addrs(|addrs| {
-            if addrs.is_empty() {
+            if let Some((index, _)) = addrs
-                addrs.push(IpCidr::Ipv4(config.address)).unwrap();
+                .iter()
-            } else {
+                .enumerate()
-                addrs[0] = IpCidr::Ipv4(config.address);
+                .find(|(_, &addr)| matches!(addr, IpCidr::Ipv4(_)))
+            {
+                addrs.remove(index);
             }
+            addrs.push(IpCidr::Ipv4(config.address)).unwrap();
         });
 
         #[cfg(feature = "medium-ethernet")]
@@ -581,11 +632,14 @@ impl<D: Driver + 'static> Inner<D> {
 
         debug!("   IP address:      {}", config.address);
         s.iface.update_ip_addrs(|addrs| {
-            if addrs.is_empty() {
+            if let Some((index, _)) = addrs
-                addrs.push(IpCidr::Ipv6(config.address)).unwrap();
+                .iter()
-            } else {
+                .enumerate()
-                addrs[0] = IpCidr::Ipv6(config.address);
+                .find(|(_, &addr)| matches!(addr, IpCidr::Ipv6(_)))
+            {
+                addrs.remove(index);
             }
+            addrs.push(IpCidr::Ipv6(config.address)).unwrap();
         });
 
         #[cfg(feature = "medium-ethernet")]
@@ -653,13 +707,21 @@ impl<D: Driver + 'static> Inner<D> {
         socket.set_retry_config(config.retry_config);
     }
 
-    #[allow(unused)] // used only with dhcp
+    #[cfg(feature = "dhcpv4")]
-    fn unapply_config(&mut self, s: &mut SocketStack) {
+    fn unapply_config_v4(&mut self, s: &mut SocketStack) {
         #[cfg(feature = "medium-ethernet")]
         let medium = self.device.capabilities().medium;
-
         debug!("Lost IP configuration");
-        s.iface.update_ip_addrs(|ip_addrs| ip_addrs.clear());
+        s.iface.update_ip_addrs(|ip_addrs| {
+            #[cfg(feature = "proto-ipv4")]
+            if let Some((index, _)) = ip_addrs
+                .iter()
+                .enumerate()
+                .find(|(_, &addr)| matches!(addr, IpCidr::Ipv4(_)))
+            {
+                ip_addrs.remove(index);
+            }
+        });
         #[cfg(feature = "medium-ethernet")]
         if medium == Medium::Ethernet {
             #[cfg(feature = "proto-ipv4")]
@@ -706,7 +768,7 @@ impl<D: Driver + 'static> Inner<D> {
             if self.link_up {
                 match socket.poll() {
                     None => {}
-                    Some(dhcpv4::Event::Deconfigured) => self.unapply_config(s),
+                    Some(dhcpv4::Event::Deconfigured) => self.unapply_config_v4(s),
                     Some(dhcpv4::Event::Configured(config)) => {
                         let config = StaticConfigV4 {
                             address: config.address,
@@ -718,7 +780,7 @@ impl<D: Driver + 'static> Inner<D> {
                 }
             } else if old_link_up {
                 socket.reset();
-                self.unapply_config(s);
+                self.unapply_config_v4(s);
             }
         }
         //if old_link_up || self.link_up {

embassy-nrf/src/pdm.rs

@@ -8,12 +8,22 @@ use core::task::Poll;
 
 use embassy_hal_common::drop::OnDrop;
 use embassy_hal_common::{into_ref, PeripheralRef};
+use fixed::types::I7F1;
 use futures::future::poll_fn;
 
 use crate::chip::EASY_DMA_SIZE;
 use crate::gpio::sealed::Pin;
 use crate::gpio::{AnyPin, Pin as GpioPin};
 use crate::interrupt::typelevel::Interrupt;
+use crate::pac::pdm::mode::{EDGE_A, OPERATION_A};
+pub use crate::pac::pdm::pdmclkctrl::FREQ_A as Frequency;
+#[cfg(any(
+    feature = "nrf52840",
+    feature = "nrf52833",
+    feature = "_nrf5340-app",
+    feature = "_nrf9160",
+))]
+pub use crate::pac::pdm::ratio::RATIO_A as Ratio;
 use crate::{interrupt, Peripheral};
 
 /// Interrupt handler.
@@ -23,7 +33,20 @@ pub struct InterruptHandler<T: Instance> {
 
 impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for InterruptHandler<T> {
     unsafe fn on_interrupt() {
-        T::regs().intenclr.write(|w| w.end().clear());
+        let r = T::regs();
+
+        if r.events_end.read().bits() != 0 {
+            r.intenclr.write(|w| w.end().clear());
+        }
+
+        if r.events_started.read().bits() != 0 {
+            r.intenclr.write(|w| w.started().clear());
+        }
+
+        if r.events_stopped.read().bits() != 0 {
+            r.intenclr.write(|w| w.stopped().clear());
+        }
+
         T::state().waker.wake();
     }
 }
@@ -44,10 +67,24 @@ pub enum Error {
     BufferZeroLength,
     /// PDM is not running
     NotRunning,
+    /// PDM is already running
+    AlreadyRunning,
 }
 
 static DUMMY_BUFFER: [i16; 1] = [0; 1];
 
+/// The state of a continuously running sampler. While it reflects
+/// the progress of a sampler, it also signals what should be done
+/// next. For example, if the sampler has stopped then the Pdm implementation
+/// can then tear down its infrastructure.
+#[derive(PartialEq)]
+pub enum SamplerState {
+    /// The sampler processed the samples and is ready for more.
+    Sampled,
+    /// The sampler is done processing samples.
+    Stopped,
+}
+
 impl<'d, T: Instance> Pdm<'d, T> {
     /// Create PDM driver
     pub fn new(
@@ -79,18 +116,24 @@ impl<'d, T: Instance> Pdm<'d, T> {
         r.psel.clk.write(|w| unsafe { w.bits(clk.psel_bits()) });
 
         // configure
-        // use default for
+        r.pdmclkctrl.write(|w| w.freq().variant(config.frequency));
-        // - gain right
+        #[cfg(any(
-        // - gain left
+            feature = "nrf52840",
-        // - clk
+            feature = "nrf52833",
-        // - ratio
+            feature = "_nrf5340-app",
+            feature = "_nrf9160",
+        ))]
+        r.ratio.write(|w| w.ratio().variant(config.ratio));
         r.mode.write(|w| {
-            w.edge().bit(config.edge == Edge::LeftRising);
+            w.operation().variant(config.operation_mode.into());
-            w.operation().bit(config.operation_mode == OperationMode::Mono);
+            w.edge().variant(config.edge.into());
             w
         });
-        r.gainl.write(|w| w.gainl().default_gain());
+
-        r.gainr.write(|w| w.gainr().default_gain());
+        Self::_set_gain(r, config.gain_left, config.gain_right);
+
+        // Disable all events interrupts
+        r.intenclr.write(|w| unsafe { w.bits(0x003F_FFFF) });
 
         // IRQ
         T::Interrupt::unpend();
@@ -101,6 +144,25 @@ impl<'d, T: Instance> Pdm<'d, T> {
         Self { _peri: pdm }
     }
 
+    fn _set_gain(r: &crate::pac::pdm::RegisterBlock, gain_left: I7F1, gain_right: I7F1) {
+        let gain_left = gain_left
+            .saturating_add(I7F1::from_bits(40))
+            .saturating_to_num::<u8>()
+            .clamp(0, 0x50);
+        let gain_right = gain_right
+            .saturating_add(I7F1::from_bits(40))
+            .saturating_to_num::<u8>()
+            .clamp(0, 0x50);
+
+        r.gainl.write(|w| unsafe { w.gainl().bits(gain_left) });
+        r.gainr.write(|w| unsafe { w.gainr().bits(gain_right) });
+    }
+
+    /// Adjust the gain of the PDM microphone on the fly
+    pub fn set_gain(&mut self, gain_left: I7F1, gain_right: I7F1) {
+        Self::_set_gain(T::regs(), gain_left, gain_right)
+    }
+
     /// Start sampling microphon data into a dummy buffer
     /// Usefull to start the microphon and keep it active between recording samples
     pub async fn start(&mut self) {
@@ -198,6 +260,108 @@ impl<'d, T: Instance> Pdm<'d, T> {
 
         compiler_fence(Ordering::SeqCst);
     }
+
+    /// Continuous sampling with double buffers.
+    ///
+    /// A sampler closure is provided that receives the buffer of samples, noting
+    /// that the size of this buffer can be less than the original buffer's size.
+    /// A command is return from the closure that indicates whether the sampling
+    /// should continue or stop.
+    ///
+    /// NOTE: The time spent within the callback supplied should not exceed the time
+    /// taken to acquire the samples into a single buffer. You should measure the
+    /// time taken by the callback and set the sample buffer size accordingly.
+    /// Exceeding this time can lead to samples becoming dropped.
+    pub async fn run_task_sampler<S, const N: usize>(
+        &mut self,
+        bufs: &mut [[i16; N]; 2],
+        mut sampler: S,
+    ) -> Result<(), Error>
+    where
+        S: FnMut(&[i16; N]) -> SamplerState,
+    {
+        let r = T::regs();
+
+        if r.events_started.read().bits() != 0 {
+            return Err(Error::AlreadyRunning);
+        }
+
+        r.sample
+            .ptr
+            .write(|w| unsafe { w.sampleptr().bits(bufs[0].as_mut_ptr() as u32) });
+        r.sample.maxcnt.write(|w| unsafe { w.buffsize().bits(N as _) });
+
+        // Reset and enable the events
+        r.events_end.reset();
+        r.events_started.reset();
+        r.events_stopped.reset();
+        r.intenset.write(|w| {
+            w.end().set();
+            w.started().set();
+            w.stopped().set();
+            w
+        });
+
+        // Don't reorder the start event before the previous writes. Hopefully self
+        // wouldn't happen anyway.
+        compiler_fence(Ordering::SeqCst);
+
+        r.tasks_start.write(|w| unsafe { w.bits(1) });
+
+        let mut current_buffer = 0;
+
+        let mut done = false;
+
+        let drop = OnDrop::new(|| {
+            r.tasks_stop.write(|w| unsafe { w.bits(1) });
+            // N.B. It would be better if this were async, but Drop only support sync code.
+            while r.events_stopped.read().bits() != 0 {}
+        });
+
+        // Wait for events and complete when the sampler indicates it has had enough.
+        poll_fn(|cx| {
+            let r = T::regs();
+
+            T::state().waker.register(cx.waker());
+
+            if r.events_end.read().bits() != 0 {
+                compiler_fence(Ordering::SeqCst);
+
+                r.events_end.reset();
+                r.intenset.write(|w| w.end().set());
+
+                if !done {
+                    // Discard the last buffer after the user requested a stop.
+                    if sampler(&bufs[current_buffer]) == SamplerState::Sampled {
+                        let next_buffer = 1 - current_buffer;
+                        current_buffer = next_buffer;
+                    } else {
+                        r.tasks_stop.write(|w| unsafe { w.bits(1) });
+                        done = true;
+                    };
+                };
+            }
+
+            if r.events_started.read().bits() != 0 {
+                r.events_started.reset();
+                r.intenset.write(|w| w.started().set());
+
+                let next_buffer = 1 - current_buffer;
+                r.sample
+                    .ptr
+                    .write(|w| unsafe { w.sampleptr().bits(bufs[next_buffer].as_mut_ptr() as u32) });
+            }
+
+            if r.events_stopped.read().bits() != 0 {
+                return Poll::Ready(());
+            }
+
+            Poll::Pending
+        })
+        .await;
+        drop.defuse();
+        Ok(())
+    }
 }
 
 /// PDM microphone driver Config
@@ -206,6 +370,20 @@ pub struct Config {
     pub operation_mode: OperationMode,
     /// On which edge the left channel should be samples
     pub edge: Edge,
+    /// Clock frequency
+    pub frequency: Frequency,
+    /// Clock ratio
+    #[cfg(any(
+        feature = "nrf52840",
+        feature = "nrf52833",
+        feature = "_nrf5340-app",
+        feature = "_nrf9160",
+    ))]
+    pub ratio: Ratio,
+    /// Gain left in dB
+    pub gain_left: I7F1,
+    /// Gain right in dB
+    pub gain_right: I7F1,
 }
 
 impl Default for Config {
@@ -213,6 +391,16 @@ impl Default for Config {
         Self {
             operation_mode: OperationMode::Mono,
             edge: Edge::LeftFalling,
+            frequency: Frequency::DEFAULT,
+            #[cfg(any(
+                feature = "nrf52840",
+                feature = "nrf52833",
+                feature = "_nrf5340-app",
+                feature = "_nrf9160",
+            ))]
+            ratio: Ratio::RATIO80,
+            gain_left: I7F1::ZERO,
+            gain_right: I7F1::ZERO,
         }
     }
 }
@@ -226,6 +414,15 @@ pub enum OperationMode {
     Stereo,
 }
 
+impl From<OperationMode> for OPERATION_A {
+    fn from(mode: OperationMode) -> Self {
+        match mode {
+            OperationMode::Mono => OPERATION_A::MONO,
+            OperationMode::Stereo => OPERATION_A::STEREO,
+        }
+    }
+}
+
 /// PDM edge polarity
 #[derive(PartialEq)]
 pub enum Edge {
@@ -235,6 +432,15 @@ pub enum Edge {
     LeftFalling,
 }
 
+impl From<Edge> for EDGE_A {
+    fn from(edge: Edge) -> Self {
+        match edge {
+            Edge::LeftRising => EDGE_A::LEFT_RISING,
+            Edge::LeftFalling => EDGE_A::LEFT_FALLING,
+        }
+    }
+}
+
 impl<'d, T: Instance> Drop for Pdm<'d, T> {
     fn drop(&mut self) {
         let r = T::regs();

embassy-rp/src/adc.rs

@@ -81,6 +81,16 @@ pub struct Adc<'d, M: Mode> {
     phantom: PhantomData<(&'d ADC, M)>,
 }
 
+impl<'d, M: Mode> Drop for Adc<'d, M> {
+    fn drop(&mut self) {
+        let r = Self::regs();
+        // disable ADC. leaving it enabled comes with a ~150µA static
+        // current draw. the temperature sensor has already been disabled
+        // by the temperature-reading methods, so we don't need to touch that.
+        r.cs().write(|w| w.set_en(false));
+    }
+}
+
 impl<'d, M: Mode> Adc<'d, M> {
     #[inline]
     fn regs() -> pac::adc::Adc {

embassy-rp/src/i2c.rs

@@ -716,6 +716,9 @@ mod nightly {
         async fn transaction(&mut self, address: A, operations: &mut [Operation<'_>]) -> Result<(), Self::Error> {
             let addr: u16 = address.into();
 
+            if operations.len() > 0 {
+                Self::setup(addr)?;
+            }
             let mut iterator = operations.iter_mut();
 
             while let Some(op) = iterator.next() {
@@ -723,11 +726,9 @@ mod nightly {
 
                 match op {
                     Operation::Read(buffer) => {
-                        Self::setup(addr)?;
                         self.read_async_internal(buffer, false, last).await?;
                     }
                     Operation::Write(buffer) => {
-                        Self::setup(addr)?;
                         self.write_async_internal(buffer.into_iter().cloned(), last).await?;
                     }
                 }

embassy-stm32/src/eth/generic_smi.rs

@@ -45,19 +45,18 @@ use self::phy_consts::*;
 pub struct GenericSMI {
     #[cfg(feature = "time")]
     poll_interval: Duration,
+    #[cfg(not(feature = "time"))]
+    _private: (),
 }
 
 impl GenericSMI {
-    #[cfg(feature = "time")]
     pub fn new() -> Self {
         Self {
+            #[cfg(feature = "time")]
             poll_interval: Duration::from_millis(500),
-        }
-    }
-
             #[cfg(not(feature = "time"))]
-    pub fn new() -> Self {
+            _private: (),
-        Self {}
+        }
     }
 }
 
@@ -102,6 +101,7 @@ unsafe impl PHY for GenericSMI {
 
 /// Public functions for the PHY
 impl GenericSMI {
+    #[cfg(feature = "time")]
     pub fn set_poll_interval(&mut self, poll_interval: Duration) {
         self.poll_interval = poll_interval
     }

embassy-stm32/src/usart/mod.rs

@@ -116,6 +116,10 @@ pub struct Config {
     /// but will effectively disable noise detection.
     #[cfg(not(usart_v1))]
     pub assume_noise_free: bool,
+
+    /// Set this to true to swap the RX and TX pins.
+    #[cfg(any(usart_v3, usart_v4))]
+    pub swap_rx_tx: bool,
 }
 
 impl Default for Config {
@@ -129,6 +133,8 @@ impl Default for Config {
             detect_previous_overrun: false,
             #[cfg(not(usart_v1))]
             assume_noise_free: false,
+            #[cfg(any(usart_v3, usart_v4))]
+            swap_rx_tx: false,
         }
     }
 }
@@ -688,8 +694,22 @@ impl<'d, T: BasicInstance, TxDma, RxDma> Uart<'d, T, TxDma, RxDma> {
 
         let r = T::regs();
 
+        // Some chips do not have swap_rx_tx bit
+        cfg_if::cfg_if! {
+            if #[cfg(any(usart_v3, usart_v4))] {
+                if config.swap_rx_tx {
+                    let (rx, tx) = (tx, rx);
                     rx.set_as_af(rx.af_num(), AFType::Input);
                     tx.set_as_af(tx.af_num(), AFType::OutputPushPull);
+                } else {
+                    rx.set_as_af(rx.af_num(), AFType::Input);
+                    tx.set_as_af(tx.af_num(), AFType::OutputPushPull);
+                }
+            } else {
+                rx.set_as_af(rx.af_num(), AFType::Input);
+                tx.set_as_af(tx.af_num(), AFType::OutputPushPull);
+            }
+        }
 
         configure(r, &config, T::frequency(), T::KIND, true, true);
 
@@ -847,6 +867,9 @@ fn configure(r: Regs, config: &Config, pclk_freq: Hertz, kind: Kind, enable_rx:
             StopBits::STOP1P5 => vals::Stop::STOP1P5,
             StopBits::STOP2 => vals::Stop::STOP2,
         });
+
+        #[cfg(any(usart_v3, usart_v4))]
+        w.set_swap(config.swap_rx_tx);
     });
     r.cr1().write(|w| {
         // enable uart

examples/nrf52840/Cargo.toml

@@ -43,6 +43,7 @@ embassy-net-esp-hosted = { version = "0.1.0", path = "../../embassy-net-esp-host
 defmt = "0.3"
 defmt-rtt = "0.4"
 
+fixed = "1.10.0"
 static_cell = "1.1"
 cortex-m = { version = "0.7.6", features = ["inline-asm", "critical-section-single-core"] }
 cortex-m-rt = "0.7.0"
@@ -53,6 +54,8 @@ embedded-storage = "0.3.0"
 usbd-hid = "0.6.0"
 serde = { version = "1.0.136", default-features = false }
 embedded-hal-async = { version = "0.2.0-alpha.2", optional = true }
+num-integer = { version = "0.1.45", default-features = false }
+microfft = "0.5.0"
 
 [patch.crates-io]
 lora-phy = { git = "https://github.com/embassy-rs/lora-phy", rev = "ad289428fd44b02788e2fa2116445cc8f640a265" }

examples/nrf52840/src/bin/pdm.rs

@@ -7,6 +7,8 @@ use embassy_executor::Spawner;
 use embassy_nrf::pdm::{self, Config, Pdm};
 use embassy_nrf::{bind_interrupts, peripherals};
 use embassy_time::{Duration, Timer};
+use fixed::types::I7F1;
+use num_integer::Roots;
 use {defmt_rtt as _, panic_probe as _};
 
 bind_interrupts!(struct Irqs {
@@ -20,6 +22,9 @@ async fn main(_p: Spawner) {
     let mut pdm = Pdm::new(p.PDM, Irqs, p.P0_01, p.P0_00, config);
 
     loop {
+        for gain in [I7F1::from_num(-20), I7F1::from_num(0), I7F1::from_num(20)] {
+            pdm.set_gain(gain, gain);
+            info!("Gain = {} dB", defmt::Debug2Format(&gain));
             pdm.start().await;
 
             // wait some time till the microphon settled
@@ -29,9 +34,24 @@ async fn main(_p: Spawner) {
             let mut buf = [0i16; SAMPLES];
             pdm.sample(&mut buf).await.unwrap();
 
+            let mean = (buf.iter().map(|v| i32::from(*v)).sum::<i32>() / buf.len() as i32) as i16;
+            info!(
+                "{} samples, min {=i16}, max {=i16}, mean {=i16}, AC RMS {=i16}",
+                buf.len(),
+                buf.iter().min().unwrap(),
+                buf.iter().max().unwrap(),
+                mean,
+                (buf.iter()
+                    .map(|v| i32::from(*v - mean).pow(2))
+                    .fold(0i32, |a, b| a.saturating_add(b))
+                    / buf.len() as i32)
+                    .sqrt() as i16,
+            );
+
             info!("samples: {:?}", &buf);
 
             pdm.stop().await;
             Timer::after(Duration::from_millis(100)).await;
         }
+    }
 }

examples/nrf52840/src/bin/pdm_continuous.rs

@@ -0,0 +1,81 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use core::cmp::Ordering;
+
+use defmt::info;
+use embassy_executor::Spawner;
+use embassy_nrf::pdm::{self, Config, Frequency, OperationMode, Pdm, Ratio, SamplerState};
+use embassy_nrf::{bind_interrupts, peripherals};
+use fixed::types::I7F1;
+use microfft::real::rfft_1024;
+use num_integer::Roots;
+use {defmt_rtt as _, panic_probe as _};
+
+// Demonstrates both continuous sampling and scanning multiple channels driven by a PPI linked timer
+
+bind_interrupts!(struct Irqs {
+    PDM => pdm::InterruptHandler<peripherals::PDM>;
+});
+
+#[embassy_executor::main]
+async fn main(_p: Spawner) {
+    let mut p = embassy_nrf::init(Default::default());
+    let mut config = Config::default();
+    // Pins are correct for the onboard microphone on the Feather nRF52840 Sense.
+    config.frequency = Frequency::_1280K; // 16 kHz sample rate
+    config.ratio = Ratio::RATIO80;
+    config.operation_mode = OperationMode::Mono;
+    config.gain_left = I7F1::from_bits(5); // 2.5 dB
+    let mut pdm = Pdm::new(p.PDM, Irqs, &mut p.P0_00, &mut p.P0_01, config);
+
+    let mut bufs = [[0; 1024]; 2];
+
+    pdm.run_task_sampler(&mut bufs, move |buf| {
+        // NOTE: It is important that the time spent within this callback
+        // does not exceed the time taken to acquire the 1500 samples we
+        // have in this example, which would be 10us + 2us per
+        // sample * 1500 = 18ms. You need to measure the time taken here
+        // and set the sample buffer size accordingly. Exceeding this
+        // time can lead to the peripheral re-writing the other buffer.
+        let mean = (buf.iter().map(|v| i32::from(*v)).sum::<i32>() / buf.len() as i32) as i16;
+        let (peak_freq_index, peak_mag) = fft_peak_freq(&buf);
+        let peak_freq = peak_freq_index * 16000 / buf.len();
+        info!(
+            "{} samples, min {=i16}, max {=i16}, mean {=i16}, AC RMS {=i16}, peak {} @ {} Hz",
+            buf.len(),
+            buf.iter().min().unwrap(),
+            buf.iter().max().unwrap(),
+            mean,
+            (buf.iter()
+                .map(|v| i32::from(*v - mean).pow(2))
+                .fold(0i32, |a, b| a.saturating_add(b))
+                / buf.len() as i32)
+                .sqrt() as i16,
+            peak_mag,
+            peak_freq,
+        );
+        SamplerState::Sampled
+    })
+    .await
+    .unwrap();
+}
+
+fn fft_peak_freq(input: &[i16; 1024]) -> (usize, u32) {
+    let mut f = [0f32; 1024];
+    for i in 0..input.len() {
+        f[i] = (input[i] as f32) / 32768.0;
+    }
+    // N.B. rfft_1024 does the FFT in-place so result is actually also a reference to f.
+    let result = rfft_1024(&mut f);
+    result[0].im = 0.0;
+
+    result
+        .iter()
+        .map(|c| c.norm_sqr())
+        .enumerate()
+        .max_by(|(_, a), (_, b)| a.partial_cmp(b).unwrap_or(Ordering::Equal))
+        .map(|(i, v)| (i, ((v * 32768.0) as u32).sqrt()))
+        .unwrap()
+}