stm32/adc: add async conversion

embassy-stm32/src/adc/f3.rs

@@ -1,14 +1,36 @@
+use core::future::poll_fn;
+use core::marker::PhantomData;
+use core::task::Poll;
+
 use embassy_hal_internal::into_ref;
 use embedded_hal_02::blocking::delay::DelayUs;
 
 use crate::adc::{Adc, AdcPin, Instance, SampleTime};
+use crate::interrupt::typelevel::Interrupt;
 use crate::time::Hertz;
-use crate::Peripheral;
+use crate::{interrupt, Peripheral};
 
 pub const VDDA_CALIB_MV: u32 = 3300;
 pub const ADC_MAX: u32 = (1 << 12) - 1;
 pub const VREF_INT: u32 = 1230;
 
+/// Interrupt handler.
+pub struct InterruptHandler<T: Instance> {
+    _phantom: PhantomData<T>,
+}
+
+impl<T: Instance> interrupt::typelevel::Handler<T::Interrupt> for InterruptHandler<T> {
+    unsafe fn on_interrupt() {
+        if T::regs().isr().read().eoc() {
+            T::regs().ier().modify(|w| w.set_eocie(false));
+        } else {
+            return;
+        }
+
+        T::state().waker.wake();
+    }
+}
+
 pub struct Vref;
 impl<T: Instance> AdcPin<T> for Vref {}
 impl<T: Instance> super::sealed::AdcPin<T> for Vref {
@@ -17,6 +39,13 @@ impl<T: Instance> super::sealed::AdcPin<T> for Vref {
     }
 }
 
+impl Vref {
+    /// The value that vref would be if vdda was at 3300mv
+    pub fn value(&self) -> u16 {
+        crate::pac::VREFINTCAL.data().read().value()
+    }
+}
+
 pub struct Temperature;
 impl<T: Instance> AdcPin<T> for Temperature {}
 impl<T: Instance> super::sealed::AdcPin<T> for Temperature {
@@ -26,7 +55,11 @@ impl<T: Instance> super::sealed::AdcPin<T> for Temperature {
 }
 
 impl<'d, T: Instance> Adc<'d, T> {
-    pub fn new(adc: impl Peripheral<P = T> + 'd, delay: &mut impl DelayUs<u32>) -> Self {
+    pub fn new(
+        adc: impl Peripheral<P = T> + 'd,
+        _irq: impl interrupt::typelevel::Binding<T::Interrupt, InterruptHandler<T>> + 'd,
+        delay: &mut impl DelayUs<u32>,
+    ) -> Self {
         use crate::pac::adc::vals;
 
         into_ref!(adc);
@@ -58,6 +91,11 @@ impl<'d, T: Instance> Adc<'d, T> {
         // Wait until the adc is ready
         while !T::regs().isr().read().adrdy() {}
 
+        T::Interrupt::unpend();
+        unsafe {
+            T::Interrupt::enable();
+        }
+
         Self {
             adc,
             sample_time: Default::default(),
@@ -97,30 +135,41 @@ impl<'d, T: Instance> Adc<'d, T> {
     }
 
     /// Perform a single conversion.
-    fn convert(&mut self) -> u16 {
+    async fn convert(&mut self) -> u16 {
         T::regs().isr().write(|_| {});
+        T::regs().ier().modify(|w| w.set_eocie(true));
         T::regs().cr().modify(|w| w.set_adstart(true));
 
-        while !T::regs().isr().read().eoc() && !T::regs().isr().read().eos() {}
+        poll_fn(|cx| {
+            T::state().waker.register(cx.waker());
+
+            if T::regs().isr().read().eoc() {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            }
+        })
+        .await;
+
         T::regs().isr().write(|_| {});
 
         T::regs().dr().read().rdata()
     }
 
-    pub fn read(&mut self, pin: &mut impl AdcPin<T>) -> u16 {
+    pub async fn read(&mut self, pin: &mut impl AdcPin<T>) -> u16 {
         Self::set_channel_sample_time(pin.channel(), self.sample_time);
 
         // Configure the channel to sample
         T::regs().sqr1().write(|w| w.set_sq(0, pin.channel()));
-        self.convert()
+        self.convert().await
     }
 
     fn set_channel_sample_time(ch: u8, sample_time: SampleTime) {
         let sample_time = sample_time.into();
         if ch <= 9 {
-            T::regs().smpr2().modify(|reg| reg.set_smp(ch as _, sample_time));
+            T::regs().smpr1().modify(|reg| reg.set_smp(ch as _, sample_time));
         } else {
-            T::regs().smpr1().modify(|reg| reg.set_smp((ch - 10) as _, sample_time));
+            T::regs().smpr2().modify(|reg| reg.set_smp((ch - 10) as _, sample_time));
         }
     }
 }

embassy-stm32/src/adc/mod.rs

@@ -31,12 +31,35 @@ pub struct Adc<'d, T: Instance> {
 }
 
 pub(crate) mod sealed {
-    pub trait Instance {
+    #[cfg(adc_f3)]
+    use embassy_sync::waitqueue::AtomicWaker;
+
+    #[cfg(adc_f3)]
+    pub struct State {
+        pub waker: AtomicWaker,
+    }
+
+    #[cfg(adc_f3)]
+    impl State {
+        pub const fn new() -> Self {
+            Self {
+                waker: AtomicWaker::new(),
+            }
+        }
+    }
+
+    pub trait InterruptableInstance {
+        type Interrupt: crate::interrupt::typelevel::Interrupt;
+    }
+
+    pub trait Instance: InterruptableInstance {
         fn regs() -> crate::pac::adc::Adc;
         #[cfg(not(any(adc_f1, adc_v1, adc_f3_v2, adc_g0)))]
         fn common_regs() -> crate::pac::adccommon::AdcCommon;
         #[cfg(adc_f3)]
         fn frequency() -> crate::time::Hertz;
+        #[cfg(adc_f3)]
+        fn state() -> &'static State;
     }
 
     pub trait AdcPin<T: Instance> {
@@ -72,8 +95,22 @@ foreach_adc!(
             fn frequency() -> crate::time::Hertz {
                 unsafe { crate::rcc::get_freqs() }.$clock.unwrap()
             }
+
+            #[cfg(adc_f3)]
+            fn state() -> &'static sealed::State {
+                static STATE: sealed::State = sealed::State::new();
+                &STATE
+            }
         }
 
+        foreach_interrupt!(
+            ($inst,adc,ADC,GLOBAL,$irq:ident) => {
+                impl sealed::InterruptableInstance for peripherals::$inst {
+                    type Interrupt = crate::interrupt::typelevel::$irq;
+                }
+            };
+        );
+
         impl crate::adc::Instance for peripherals::$inst {}
     };
 );

examples/stm32f334/src/bin/adc.rs

@@ -4,13 +4,18 @@
 
 use defmt::info;
 use embassy_executor::Spawner;
-use embassy_stm32::adc::{Adc, SampleTime, VREF_INT};
+use embassy_stm32::adc::{Adc, SampleTime};
+use embassy_stm32::peripherals::ADC1;
 use embassy_stm32::rcc::AdcClockSource;
 use embassy_stm32::time::mhz;
-use embassy_stm32::Config;
+use embassy_stm32::{adc, bind_interrupts, Config};
 use embassy_time::{Delay, Duration, Timer};
 use {defmt_rtt as _, panic_probe as _};
 
+bind_interrupts!(struct Irqs {
+    ADC1_2 => adc::InterruptHandler<ADC1>;
+});
+
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) -> ! {
     let mut config = Config::default();
@@ -24,7 +29,7 @@ async fn main(_spawner: Spawner) -> ! {
 
     info!("create adc...");
 
-    let mut adc = Adc::new(p.ADC1, &mut Delay);
+    let mut adc = Adc::new(p.ADC1, Irqs, &mut Delay);
 
     adc.set_sample_time(SampleTime::Cycles601_5);
 
@@ -34,18 +39,18 @@ async fn main(_spawner: Spawner) -> ! {
     let mut temperature = adc.enable_temperature();
 
     loop {
-        let vref = adc.read(&mut vrefint);
+        let vref = adc.read(&mut vrefint).await;
-        info!("read vref: {}", vref);
+        info!("read vref: {} (should be {})", vref, vrefint.value());
 
-        let temp = adc.read(&mut temperature);
+        let temp = adc.read(&mut temperature).await;
         info!("read temperature: {}", temp);
 
-        let pin = adc.read(&mut p.PA0);
+        let pin = adc.read(&mut p.PA0).await;
         info!("read pin: {}", pin);
 
-        let pin_mv = pin as u32 * VREF_INT as u32 / vref as u32;
+        let pin_mv = (pin as u32 * vrefint.value() as u32 / vref as u32) * 3300 / 4095;
         info!("computed pin mv: {}", pin_mv);
 
-        Timer::after(Duration::from_secs(1)).await;
+        Timer::after(Duration::from_millis(500)).await;
     }
 }