Merge #756

756: Add async quadrature decoder for embassy-nrf r=Dirbaio a=kalkyl

Thsi PR adds an async interface to the QDEC peripheral to embassy-nrf, that can be used for rotary encoders for example.

Co-authored-by: Henrik Alsér <henrik@mindbite.se>
Co-authored-by: Henrik Alsér <henrik.alser@me.com>
Co-authored-by: Henrik Alsér <henrik.alser@me.com>

embassy-nrf/src/chips/nrf52805.rs

@@ -122,6 +122,9 @@ embassy_hal_common::peripherals! {
 
     // TEMP
     TEMP,
+
+    // QDEC
+    QDEC,
 }
 
 impl_uarte!(UARTE0, UARTE0, UARTE0_UART0);

embassy-nrf/src/chips/nrf52810.rs

@@ -125,6 +125,9 @@ embassy_hal_common::peripherals! {
 
     // TEMP
     TEMP,
+
+    // QDEC
+    QDEC,
 }
 
 impl_uarte!(UARTE0, UARTE0, UARTE0_UART0);

embassy-nrf/src/chips/nrf52811.rs

@@ -125,6 +125,9 @@ embassy_hal_common::peripherals! {
 
     // TEMP
     TEMP,
+
+    // QDEC
+    QDEC,
 }
 
 impl_uarte!(UARTE0, UARTE0, UARTE0_UART0);

embassy-nrf/src/chips/nrf52820.rs

@@ -123,6 +123,9 @@ embassy_hal_common::peripherals! {
 
     // TEMP
     TEMP,
+
+    // QDEC
+    QDEC,
 }
 
 #[cfg(feature = "nightly")]

embassy-nrf/src/chips/nrf52832.rs

@@ -135,6 +135,9 @@ embassy_hal_common::peripherals! {
 
     // TEMP
     TEMP,
+
+    // QDEC
+    QDEC,
 }
 
 impl_uarte!(UARTE0, UARTE0, UARTE0_UART0);

embassy-nrf/src/chips/nrf52833.rs

@@ -155,6 +155,9 @@ embassy_hal_common::peripherals! {
 
     // TEMP
     TEMP,
+
+    // QDEC
+    QDEC,
 }
 
 #[cfg(feature = "nightly")]

embassy-nrf/src/chips/nrf52840.rs

@@ -27,6 +27,9 @@ embassy_hal_common::peripherals! {
     // QSPI
     QSPI,
 
+    // QDEC
+    QDEC,
+
     // UARTE
     UARTE0,
     UARTE1,

embassy-nrf/src/lib.rs

@@ -74,6 +74,8 @@ pub mod nvmc;
 pub mod ppi;
 #[cfg(not(any(feature = "nrf52805", feature = "nrf52820", feature = "_nrf5340-net")))]
 pub mod pwm;
+#[cfg(not(any(feature = "nrf51", feature = "_nrf9160", feature = "_nrf5340")))]
+pub mod qdec;
 #[cfg(feature = "nrf52840")]
 pub mod qspi;
 #[cfg(not(any(feature = "_nrf5340", feature = "_nrf9160")))]

embassy-nrf/src/qdec.rs

@@ -0,0 +1,216 @@
+//! Quadrature decoder interface
+
+use crate::gpio::sealed::Pin as _;
+use crate::gpio::{AnyPin, Pin as GpioPin};
+use crate::interrupt;
+use crate::pac;
+use crate::peripherals::QDEC;
+
+use core::marker::PhantomData;
+use core::task::Poll;
+use embassy::interrupt::InterruptExt;
+use embassy::util::Unborrow;
+use embassy::waitqueue::AtomicWaker;
+use embassy_hal_common::unborrow;
+use futures::future::poll_fn;
+
+/// Quadrature decoder
+pub struct Qdec<'d> {
+    phantom: PhantomData<&'d QDEC>,
+}
+
+#[non_exhaustive]
+pub struct Config {
+    pub num_samples: NumSamples,
+    pub period: SamplePeriod,
+    pub led_polarity: LedPolarity,
+    pub debounce: bool,
+    pub led_pre_usecs: u16,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            num_samples: NumSamples::_1smpl,
+            period: SamplePeriod::_256us,
+            led_polarity: LedPolarity::ActiveHigh,
+            debounce: true,
+            led_pre_usecs: 0,
+        }
+    }
+}
+
+static WAKER: AtomicWaker = AtomicWaker::new();
+
+impl<'d> Qdec<'d> {
+    pub fn new(
+        qdec: impl Unborrow<Target = QDEC> + 'd,
+        irq: impl Unborrow<Target = interrupt::QDEC> + 'd,
+        a: impl Unborrow<Target = impl GpioPin> + 'd,
+        b: impl Unborrow<Target = impl GpioPin> + 'd,
+        config: Config,
+    ) -> Self {
+        unborrow!(a, b);
+        Self::new_inner(qdec, irq, a.degrade(), b.degrade(), None, config)
+    }
+
+    pub fn new_with_led(
+        qdec: impl Unborrow<Target = QDEC> + 'd,
+        irq: impl Unborrow<Target = interrupt::QDEC> + 'd,
+        a: impl Unborrow<Target = impl GpioPin> + 'd,
+        b: impl Unborrow<Target = impl GpioPin> + 'd,
+        led: impl Unborrow<Target = impl GpioPin> + 'd,
+        config: Config,
+    ) -> Self {
+        unborrow!(a, b, led);
+        Self::new_inner(
+            qdec,
+            irq,
+            a.degrade(),
+            b.degrade(),
+            Some(led.degrade()),
+            config,
+        )
+    }
+
+    fn new_inner(
+        _t: impl Unborrow<Target = QDEC> + 'd,
+        irq: impl Unborrow<Target = interrupt::QDEC> + 'd,
+        a: AnyPin,
+        b: AnyPin,
+        led: Option<AnyPin>,
+        config: Config,
+    ) -> Self {
+        unborrow!(irq);
+        let r = Self::regs();
+
+        // Select pins.
+        a.conf().write(|w| w.input().connect().pull().pullup());
+        b.conf().write(|w| w.input().connect().pull().pullup());
+        r.psel.a.write(|w| unsafe { w.bits(a.psel_bits()) });
+        r.psel.b.write(|w| unsafe { w.bits(b.psel_bits()) });
+        if let Some(led_pin) = &led {
+            led_pin.conf().write(|w| w.dir().output());
+            r.psel.led.write(|w| unsafe { w.bits(led_pin.psel_bits()) });
+        }
+
+        // Enables/disable input debounce filters
+        r.dbfen.write(|w| match config.debounce {
+            true => w.dbfen().enabled(),
+            false => w.dbfen().disabled(),
+        });
+
+        // Set LED output pin polarity
+        r.ledpol.write(|w| match config.led_polarity {
+            LedPolarity::ActiveHigh => w.ledpol().active_high(),
+            LedPolarity::ActiveLow => w.ledpol().active_low(),
+        });
+
+        // Set time period the LED is switched ON prior to sampling (0..511 us).
+        r.ledpre
+            .write(|w| unsafe { w.ledpre().bits(config.led_pre_usecs.min(511)) });
+
+        // Set sample period
+        r.sampleper.write(|w| match config.period {
+            SamplePeriod::_128us => w.sampleper()._128us(),
+            SamplePeriod::_256us => w.sampleper()._256us(),
+            SamplePeriod::_512us => w.sampleper()._512us(),
+            SamplePeriod::_1024us => w.sampleper()._1024us(),
+            SamplePeriod::_2048us => w.sampleper()._2048us(),
+            SamplePeriod::_4096us => w.sampleper()._4096us(),
+            SamplePeriod::_8192us => w.sampleper()._8192us(),
+            SamplePeriod::_16384us => w.sampleper()._16384us(),
+            SamplePeriod::_32ms => w.sampleper()._32ms(),
+            SamplePeriod::_65ms => w.sampleper()._65ms(),
+            SamplePeriod::_131ms => w.sampleper()._131ms(),
+        });
+
+        // Enable peripheral
+        r.enable.write(|w| w.enable().set_bit());
+
+        // Start sampling
+        unsafe { r.tasks_start.write(|w| w.bits(1)) };
+
+        irq.disable();
+        irq.set_handler(|_| {
+            let r = Self::regs();
+            r.intenclr.write(|w| w.reportrdy().clear());
+            WAKER.wake();
+        });
+        irq.enable();
+
+        Self {
+            phantom: PhantomData,
+        }
+    }
+
+    /// Perform an asynchronous read of the decoder.
+    /// The returned future can be awaited to obtain the number of steps.
+    ///
+    /// If the future is dropped, the read is cancelled.
+    ///
+    /// # Example
+    ///
+    /// ```no_run
+    /// let irq = interrupt::take!(QDEC);
+    /// let config = qdec::Config::default();
+    /// let mut q = Qdec::new(p.QDEC, p.P0_31, p.P0_30, config);
+    /// let delta = q.read().await;
+    /// ```
+    pub async fn read(&mut self) -> i16 {
+        let t = Self::regs();
+        t.intenset.write(|w| w.reportrdy().set());
+        unsafe { t.tasks_readclracc.write(|w| w.bits(1)) };
+
+        let value = poll_fn(|cx| {
+            WAKER.register(cx.waker());
+            if t.events_reportrdy.read().bits() == 0 {
+                return Poll::Pending;
+            } else {
+                t.events_reportrdy.reset();
+                let acc = t.accread.read().bits();
+                Poll::Ready(acc as i16)
+            }
+        })
+        .await;
+        value
+    }
+
+    fn regs() -> &'static pac::qdec::RegisterBlock {
+        unsafe { &*pac::QDEC::ptr() }
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum SamplePeriod {
+    _128us,
+    _256us,
+    _512us,
+    _1024us,
+    _2048us,
+    _4096us,
+    _8192us,
+    _16384us,
+    _32ms,
+    _65ms,
+    _131ms,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum NumSamples {
+    _10smpl,
+    _40smpl,
+    _80smpl,
+    _120smpl,
+    _160smpl,
+    _200smpl,
+    _240smpl,
+    _280smpl,
+    _1smpl,
+}
+
+#[derive(Debug, Eq, PartialEq, Clone, Copy)]
+pub enum LedPolarity {
+    ActiveHigh,
+    ActiveLow,
+}

examples/nrf/src/bin/qdec.rs

@@ -0,0 +1,28 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::info;
+use embassy::executor::Spawner;
+use embassy_nrf::{
+    interrupt,
+    qdec::{self, Qdec},
+    Peripherals,
+};
+
+use defmt_rtt as _; // global logger
+use panic_probe as _;
+
+#[embassy::main]
+async fn main(_spawner: Spawner, p: Peripherals) {
+    let irq = interrupt::take!(QDEC);
+    let config = qdec::Config::default();
+    let mut rotary_enc = Qdec::new(p.QDEC, irq, p.P0_31, p.P0_30, config);
+
+    info!("Turn rotary encoder!");
+    let mut value = 0;
+    loop {
+        value += rotary_enc.read().await;
+        info!("Value: {}", value);
+    }
+}