Merge pull request #4832 from xoviat/adc

stm32/adc: merge v2 and v3 ringbuffers

6 files changed, 232 insertions, 493 deletions

diff --git a/embassy-stm32/CHANGELOG.md b/embassy-stm32/CHANGELOG.md
index 71989eb3d..c717235e2 100644
--- a/embassy-stm32/CHANGELOG.md
+++ b/embassy-stm32/CHANGELOG.md
@@ -38,6 +38,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - fix: usart: fix race condition in ringbuffered usart
 - feat: stm32/fdcan: add ability to control automatic recovery from bus off ([#4821](https://github.com/embassy-rs/embassy/pull/4821))
 - low-power: update rtc api to allow reconfig
+- adc: consolidate ringbuffer
 - feat: Added RTC low-power support for STM32WLEx ([#4716](https://github.com/embassy-rs/embassy/pull/4716))
 
 ## 0.4.0 - 2025-08-26
diff --git a/embassy-stm32/src/adc/ringbuffered_v3.rs b/embassy-stm32/src/adc/ringbuffered.rs
index 0aee309e3..1f384efb5 100644
--- a/embassy-stm32/src/adc/ringbuffered_v3.rs
+++ b/embassy-stm32/src/adc/ringbuffered.rs
@@ -1,9 +1,13 @@
 use core::marker::PhantomData;
 use core::sync::atomic::{Ordering, compiler_fence};
 
+#[allow(unused_imports)]
 use embassy_hal_internal::Peri;
 
+use crate::adc::Adc;
+#[allow(unused_imports)]
 use crate::adc::{Instance, RxDma};
+#[allow(unused_imports)]
 use crate::dma::{ReadableRingBuffer, TransferOptions};
 use crate::rcc;
 
@@ -11,8 +15,8 @@ use crate::rcc;
 pub struct OverrunError;
 
 pub struct RingBufferedAdc<'d, T: Instance> {
-    pub _phantom: PhantomData<T>,
-    pub ring_buf: ReadableRingBuffer<'d, u16>,
+    _phantom: PhantomData<T>,
+    ring_buf: ReadableRingBuffer<'d, u16>,
 }
 
 impl<'d, T: Instance> RingBufferedAdc<'d, T> {
@@ -36,49 +40,26 @@ impl<'d, T: Instance> RingBufferedAdc<'d, T> {
         }
     }
 
-    #[inline]
-    fn start_continuous_sampling(&mut self) {
-        // Start adc conversion
-        T::regs().cr().modify(|reg| {
-            reg.set_adstart(true);
-        });
+    /// Turns on ADC if it is not already turned on and starts continuous DMA transfer.
+    pub fn start(&mut self) {
+        compiler_fence(Ordering::SeqCst);
         self.ring_buf.start();
-    }
 
-    #[inline]
-    pub fn stop_continuous_sampling(&mut self) {
-        // Stop adc conversion
-        if T::regs().cr().read().adstart() && !T::regs().cr().read().addis() {
-            T::regs().cr().modify(|reg| {
-                reg.set_adstp(true);
-            });
-            while T::regs().cr().read().adstart() {}
-        }
-    }
-    pub fn disable_adc(&mut self) {
-        self.stop_continuous_sampling();
-        self.ring_buf.clear();
-        self.ring_buf.request_pause();
+        Adc::<T>::start();
     }
 
-    pub fn teardown_adc(&mut self) {
-        self.disable_adc();
+    pub fn stop(&mut self) {
+        Adc::<T>::stop();
 
-        //disable dma control
-        #[cfg(not(any(adc_g0, adc_u0)))]
-        T::regs().cfgr().modify(|reg| {
-            reg.set_dmaen(false);
-        });
-        #[cfg(any(adc_g0, adc_u0))]
-        T::regs().cfgr1().modify(|reg| {
-            reg.set_dmaen(false);
-        });
-
-        //TODO: do we need to cleanup the DMA request here?
+        self.ring_buf.request_pause();
 
         compiler_fence(Ordering::SeqCst);
     }
 
+    pub fn clear(&mut self) {
+        self.ring_buf.clear();
+    }
+
     /// Reads measurements from the DMA ring buffer.
     ///
     /// This method fills the provided `measurements` array with ADC readings from the DMA buffer.
@@ -131,11 +112,18 @@ impl<'d, T: Instance> RingBufferedAdc<'d, T> {
             "Buffer size must be half the size of the ring buffer"
         );
 
-        let r = T::regs();
+        if !self.ring_buf.is_running() {
+            self.start();
+        }
 
-        // Start background receive if it was not already started
-        if !r.cr().read().adstart() {
-            self.start_continuous_sampling();
+        #[cfg(adc_v2)]
+        {
+            // Clear overrun flag if set.
+            if T::regs().sr().read().ovr() {
+                self.stop();
+
+                return Err(OverrunError);
+            }
         }
 
         self.ring_buf.read_exact(measurements).await.map_err(|_| OverrunError)
@@ -150,13 +138,19 @@ impl<'d, T: Instance> RingBufferedAdc<'d, T> {
     /// Receive in the background is terminated if an error is returned.
     /// It must then manually be started again by calling `start_continuous_sampling()` or by re-calling `blocking_read()`.
     pub fn blocking_read(&mut self, buf: &mut [u16]) -> Result<usize, OverrunError> {
-        let r = T::regs();
-
-        // Start background receive if it was not already started
-        if !r.cr().read().adstart() {
-            self.start_continuous_sampling();
+        if !self.ring_buf.is_running() {
+            self.start();
         }
 
+        #[cfg(adc_v2)]
+        {
+            // Clear overrun flag if set.
+            if T::regs().sr().read().ovr() {
+                self.stop();
+
+                return Err(OverrunError);
+            }
+        }
         loop {
             match self.ring_buf.read(buf) {
                 Ok((0, _)) => {}
@@ -164,7 +158,8 @@ impl<'d, T: Instance> RingBufferedAdc<'d, T> {
                     return Ok(len);
                 }
                 Err(_) => {
-                    self.stop_continuous_sampling();
+                    self.stop();
+
                     return Err(OverrunError);
                 }
             }
@@ -174,7 +169,11 @@ impl<'d, T: Instance> RingBufferedAdc<'d, T> {
 
 impl<T: Instance> Drop for RingBufferedAdc<'_, T> {
     fn drop(&mut self) {
-        self.teardown_adc();
+        Adc::<T>::teardown_adc();
+
+        compiler_fence(Ordering::SeqCst);
+
+        self.ring_buf.request_pause();
         rcc::disable::<T>();
     }
 }
diff --git a/embassy-stm32/src/adc/ringbuffered_v2.rs b/embassy-stm32/src/adc/ringbuffered_v2.rs
deleted file mode 100644
index 9b2e5b8fe..000000000
--- a/embassy-stm32/src/adc/ringbuffered_v2.rs
+++ /dev/null
@@ -1,432 +0,0 @@
-use core::marker::PhantomData;
-use core::mem;
-use core::sync::atomic::{Ordering, compiler_fence};
-
-use stm32_metapac::adc::vals::SampleTime;
-
-use crate::adc::{Adc, AdcChannel, Instance, RxDma};
-use crate::dma::{Priority, ReadableRingBuffer, TransferOptions};
-use crate::pac::adc::vals;
-use crate::{Peri, rcc};
-
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-pub struct OverrunError;
-
-fn clear_interrupt_flags(r: crate::pac::adc::Adc) {
-    r.sr().modify(|regs| {
-        regs.set_eoc(false);
-        regs.set_ovr(false);
-    });
-}
-
-#[derive(PartialOrd, PartialEq, Debug, Clone, Copy)]
-pub enum Sequence {
-    One,
-    Two,
-    Three,
-    Four,
-    Five,
-    Six,
-    Seven,
-    Eight,
-    Nine,
-    Ten,
-    Eleven,
-    Twelve,
-    Thirteen,
-    Fourteen,
-    Fifteen,
-    Sixteen,
-}
-
-impl From<Sequence> for u8 {
-    fn from(s: Sequence) -> u8 {
-        match s {
-            Sequence::One => 0,
-            Sequence::Two => 1,
-            Sequence::Three => 2,
-            Sequence::Four => 3,
-            Sequence::Five => 4,
-            Sequence::Six => 5,
-            Sequence::Seven => 6,
-            Sequence::Eight => 7,
-            Sequence::Nine => 8,
-            Sequence::Ten => 9,
-            Sequence::Eleven => 10,
-            Sequence::Twelve => 11,
-            Sequence::Thirteen => 12,
-            Sequence::Fourteen => 13,
-            Sequence::Fifteen => 14,
-            Sequence::Sixteen => 15,
-        }
-    }
-}
-
-impl From<u8> for Sequence {
-    fn from(val: u8) -> Self {
-        match val {
-            0 => Sequence::One,
-            1 => Sequence::Two,
-            2 => Sequence::Three,
-            3 => Sequence::Four,
-            4 => Sequence::Five,
-            5 => Sequence::Six,
-            6 => Sequence::Seven,
-            7 => Sequence::Eight,
-            8 => Sequence::Nine,
-            9 => Sequence::Ten,
-            10 => Sequence::Eleven,
-            11 => Sequence::Twelve,
-            12 => Sequence::Thirteen,
-            13 => Sequence::Fourteen,
-            14 => Sequence::Fifteen,
-            15 => Sequence::Sixteen,
-            _ => panic!("Invalid sequence number"),
-        }
-    }
-}
-
-pub struct RingBufferedAdc<'d, T: Instance> {
-    _phantom: PhantomData<T>,
-    ring_buf: ReadableRingBuffer<'d, u16>,
-}
-
-impl<'d, T: Instance> Adc<'d, T> {
-    /// Configures the ADC to use a DMA ring buffer for continuous data acquisition.
-    ///
-    /// The `dma_buf` should be large enough to prevent DMA buffer overrun.
-    /// The length of the `dma_buf` should be a multiple of the ADC channel count.
-    /// For example, if 3 channels are measured, its length can be 3 * 40 = 120 measurements.
-    ///
-    /// `read` method is used to read out measurements from the DMA ring buffer, and its buffer should be exactly half of the `dma_buf` length.
-    /// It is critical to call `read` frequently to prevent DMA buffer overrun.
-    ///
-    /// [`read`]: #method.read
-    pub fn into_ring_buffered(self, dma: Peri<'d, impl RxDma<T>>, dma_buf: &'d mut [u16]) -> RingBufferedAdc<'d, T> {
-        assert!(!dma_buf.is_empty() && dma_buf.len() <= 0xFFFF);
-
-        let opts: crate::dma::TransferOptions = TransferOptions {
-            half_transfer_ir: true,
-            priority: Priority::VeryHigh,
-            ..Default::default()
-        };
-
-        // Safety: we forget the struct before this function returns.
-        let rx_src = T::regs().dr().as_ptr() as *mut u16;
-        let request = dma.request();
-
-        let ring_buf = unsafe { ReadableRingBuffer::new(dma, request, rx_src, dma_buf, opts) };
-
-        // Don't disable the clock
-        mem::forget(self);
-
-        RingBufferedAdc {
-            _phantom: PhantomData,
-            ring_buf,
-        }
-    }
-}
-
-impl<'d, T: Instance> RingBufferedAdc<'d, T> {
-    fn is_on() -> bool {
-        T::regs().cr2().read().adon()
-    }
-
-    fn stop_adc() {
-        T::regs().cr2().modify(|reg| {
-            reg.set_adon(false);
-        });
-    }
-
-    fn start_adc() {
-        T::regs().cr2().modify(|reg| {
-            reg.set_adon(true);
-        });
-    }
-
-    /// Sets the channel sample time
-    ///
-    /// ## SAFETY:
-    /// - ADON == 0 i.e ADC must not be enabled when this is called.
-    unsafe fn set_channel_sample_time(ch: u8, sample_time: SampleTime) {
-        if ch <= 9 {
-            T::regs().smpr2().modify(|reg| reg.set_smp(ch as _, sample_time));
-        } else {
-            T::regs().smpr1().modify(|reg| reg.set_smp((ch - 10) as _, sample_time));
-        }
-    }
-
-    fn set_channels_sample_time(&mut self, ch: &[u8], sample_time: SampleTime) {
-        let ch_iter = ch.iter();
-        for idx in ch_iter {
-            unsafe {
-                Self::set_channel_sample_time(*idx, sample_time);
-            }
-        }
-    }
-
-    pub fn set_sample_sequence(
-        &mut self,
-        sequence: Sequence,
-        channel: &mut impl AdcChannel<T>,
-        sample_time: SampleTime,
-    ) {
-        let was_on = Self::is_on();
-        if !was_on {
-            Self::start_adc();
-        }
-
-        // Check the sequence is long enough
-        T::regs().sqr1().modify(|r| {
-            let prev: Sequence = r.l().into();
-            if prev < sequence {
-                let new_l: Sequence = sequence;
-                trace!("Setting sequence length from {:?} to {:?}", prev as u8, new_l as u8);
-                r.set_l(sequence.into())
-            } else {
-                r.set_l(prev.into())
-            }
-        });
-
-        // Set this GPIO as an analog input.
-        channel.setup();
-
-        // Set the channel in the right sequence field.
-        match sequence {
-            Sequence::One => T::regs().sqr3().modify(|w| w.set_sq(0, channel.channel())),
-            Sequence::Two => T::regs().sqr3().modify(|w| w.set_sq(1, channel.channel())),
-            Sequence::Three => T::regs().sqr3().modify(|w| w.set_sq(2, channel.channel())),
-            Sequence::Four => T::regs().sqr3().modify(|w| w.set_sq(3, channel.channel())),
-            Sequence::Five => T::regs().sqr3().modify(|w| w.set_sq(4, channel.channel())),
-            Sequence::Six => T::regs().sqr3().modify(|w| w.set_sq(5, channel.channel())),
-            Sequence::Seven => T::regs().sqr2().modify(|w| w.set_sq(0, channel.channel())),
-            Sequence::Eight => T::regs().sqr2().modify(|w| w.set_sq(1, channel.channel())),
-            Sequence::Nine => T::regs().sqr2().modify(|w| w.set_sq(2, channel.channel())),
-            Sequence::Ten => T::regs().sqr2().modify(|w| w.set_sq(3, channel.channel())),
-            Sequence::Eleven => T::regs().sqr2().modify(|w| w.set_sq(4, channel.channel())),
-            Sequence::Twelve => T::regs().sqr2().modify(|w| w.set_sq(5, channel.channel())),
-            Sequence::Thirteen => T::regs().sqr1().modify(|w| w.set_sq(0, channel.channel())),
-            Sequence::Fourteen => T::regs().sqr1().modify(|w| w.set_sq(1, channel.channel())),
-            Sequence::Fifteen => T::regs().sqr1().modify(|w| w.set_sq(2, channel.channel())),
-            Sequence::Sixteen => T::regs().sqr1().modify(|w| w.set_sq(3, channel.channel())),
-        };
-
-        if !was_on {
-            Self::stop_adc();
-        }
-
-        self.set_channels_sample_time(&[channel.channel()], sample_time);
-
-        Self::start_adc();
-    }
-
-    /// Turns on ADC if it is not already turned on and starts continuous DMA transfer.
-    pub fn start(&mut self) -> Result<(), OverrunError> {
-        self.setup_adc();
-        self.ring_buf.clear();
-
-        Ok(())
-    }
-
-    fn stop(&mut self, err: OverrunError) -> Result<usize, OverrunError> {
-        self.teardown_adc();
-        Err(err)
-    }
-
-    /// Stops DMA transfer.
-    /// It does not turn off ADC.
-    /// Calling `start` restarts continuous DMA transfer.
-    ///
-    /// [`start`]: #method.start
-    pub fn teardown_adc(&mut self) {
-        // Stop the DMA transfer
-        self.ring_buf.request_pause();
-
-        let r = T::regs();
-
-        // Stop ADC
-        r.cr2().modify(|reg| {
-            // Stop ADC
-            reg.set_swstart(false);
-            // Stop DMA
-            reg.set_dma(false);
-        });
-
-        r.cr1().modify(|w| {
-            // Disable interrupt for end of conversion
-            w.set_eocie(false);
-            // Disable interrupt for overrun
-            w.set_ovrie(false);
-        });
-
-        clear_interrupt_flags(r);
-
-        compiler_fence(Ordering::SeqCst);
-    }
-
-    fn setup_adc(&mut self) {
-        compiler_fence(Ordering::SeqCst);
-
-        self.ring_buf.start();
-
-        let r = T::regs();
-
-        // Enable ADC
-        let was_on = Self::is_on();
-        if !was_on {
-            r.cr2().modify(|reg| {
-                reg.set_adon(false);
-                reg.set_swstart(false);
-            });
-        }
-
-        // Clear all interrupts
-        r.sr().modify(|regs| {
-            regs.set_eoc(false);
-            regs.set_ovr(false);
-            regs.set_strt(false);
-        });
-
-        r.cr1().modify(|w| {
-            // Enable interrupt for end of conversion
-            w.set_eocie(true);
-            // Enable interrupt for overrun
-            w.set_ovrie(true);
-            // Scanning converisons of multiple channels
-            w.set_scan(true);
-            // Continuous conversion mode
-            w.set_discen(false);
-        });
-
-        r.cr2().modify(|w| {
-            // Enable DMA mode
-            w.set_dma(true);
-            // Enable continuous conversions
-            w.set_cont(true);
-            // DMA requests are issues as long as DMA=1 and data are converted.
-            w.set_dds(vals::Dds::CONTINUOUS);
-            // EOC flag is set at the end of each conversion.
-            w.set_eocs(vals::Eocs::EACH_CONVERSION);
-        });
-
-        // Begin ADC conversions
-        T::regs().cr2().modify(|reg| {
-            reg.set_adon(true);
-            reg.set_swstart(true);
-        });
-
-        super::blocking_delay_us(3);
-    }
-
-    /// Read bytes that are readily available in the ring buffer.
-    /// If no bytes are currently available in the buffer the call waits until the some
-    /// bytes are available (at least one byte and at most half the buffer size)
-    ///
-    /// Background receive is started if `start()` has not been previously called.
-    ///
-    /// Receive in the background is terminated if an error is returned.
-    /// It must then manually be started again by calling `start()` or by re-calling `read()`.
-    pub fn blocking_read<const N: usize>(&mut self, buf: &mut [u16; N]) -> Result<usize, OverrunError> {
-        let r = T::regs();
-
-        // Start background receive if it was not already started
-        if !r.cr2().read().dma() {
-            self.start()?;
-        }
-
-        // Clear overrun flag if set.
-        if r.sr().read().ovr() {
-            return self.stop(OverrunError);
-        }
-
-        loop {
-            match self.ring_buf.read(buf) {
-                Ok((0, _)) => {}
-                Ok((len, _)) => {
-                    return Ok(len);
-                }
-                Err(_) => {
-                    return self.stop(OverrunError);
-                }
-            }
-        }
-    }
-
-    /// Reads measurements from the DMA ring buffer.
-    ///
-    /// This method fills the provided `measurements` array with ADC readings from the DMA buffer.
-    /// The length of the `measurements` array should be exactly half of the DMA buffer length. Because interrupts are only generated if half or full DMA transfer completes.
-    ///
-    /// Each call to `read` will populate the `measurements` array in the same order as the channels defined with `set_sample_sequence`.
-    /// There will be many sequences worth of measurements in this array because it only returns if at least half of the DMA buffer is filled.
-    /// For example if 3 channels are sampled `measurements` contain: `[sq0 sq1 sq3 sq0 sq1 sq3 sq0 sq1 sq3 sq0 sq1 sq3..]`.
-    ///
-    /// If an error is returned, it indicates a DMA overrun, and the process must be restarted by calling `start` or `read` again.
-    ///
-    /// By default, the ADC fills the DMA buffer as quickly as possible. To control the sample rate, call `teardown_adc` after each readout, and then start the DMA again at the desired interval.
-    /// Note that even if using `teardown_adc` to control the sample rate, with each call to `read`, measurements equivalent to half the size of the DMA buffer are still collected.
-    ///
-    /// Example:
-    /// ```rust,ignore
-    /// const DMA_BUF_LEN: usize = 120;
-    /// let adc_dma_buf = [0u16; DMA_BUF_LEN];
-    /// let mut adc: RingBufferedAdc<embassy_stm32::peripherals::ADC1> = adc.into_ring_buffered(p.DMA2_CH0, adc_dma_buf);
-    ///
-    /// adc.set_sample_sequence(Sequence::One, &mut p.PA0, SampleTime::CYCLES112);
-    /// adc.set_sample_sequence(Sequence::Two, &mut p.PA1, SampleTime::CYCLES112);
-    /// adc.set_sample_sequence(Sequence::Three, &mut p.PA2, SampleTime::CYCLES112);
-    ///
-    /// let mut measurements = [0u16; DMA_BUF_LEN / 2];
-    /// loop {
-    ///     match adc.read(&mut measurements).await {
-    ///         Ok(_) => {
-    ///             defmt::info!("adc1: {}", measurements);
-    ///             // Only needed to manually control sample rate.
-    ///             adc.teardown_adc();
-    ///         }
-    ///         Err(e) => {
-    ///             defmt::warn!("Error: {:?}", e);
-    ///             // DMA overrun, next call to `read` restarts ADC.
-    ///         }
-    ///     }
-    ///
-    ///     // Manually control sample rate.
-    ///     Timer::after_millis(100).await;
-    /// }
-    /// ```
-    ///
-    ///
-    /// [`set_sample_sequence`]: #method.set_sample_sequence
-    /// [`teardown_adc`]: #method.teardown_adc
-    /// [`start`]: #method.start
-    pub async fn read<const N: usize>(&mut self, measurements: &mut [u16; N]) -> Result<usize, OverrunError> {
-        assert_eq!(
-            self.ring_buf.capacity() / 2,
-            N,
-            "Buffer size must be half the size of the ring buffer"
-        );
-
-        let r = T::regs();
-
-        // Start background receive if it was not already started
-        if !r.cr2().read().dma() {
-            self.start()?;
-        }
-
-        // Clear overrun flag if set.
-        if r.sr().read().ovr() {
-            return self.stop(OverrunError);
-        }
-        match self.ring_buf.read_exact(measurements).await {
-            Ok(len) => Ok(len),
-            Err(_) => self.stop(OverrunError),
-        }
-    }
-}
-
-impl<T: Instance> Drop for RingBufferedAdc<'_, T> {
-    fn drop(&mut self) {
-        self.teardown_adc();
-        rcc::disable::<T>();
-    }
-}
diff --git a/embassy-stm32/src/adc/v2.rs b/embassy-stm32/src/adc/v2.rs
index 93ec78548..90c6294d2 100644
--- a/embassy-stm32/src/adc/v2.rs
+++ b/embassy-stm32/src/adc/v2.rs
@@ -1,11 +1,22 @@
+use core::mem;
+use core::sync::atomic::{Ordering, compiler_fence};
+
 use super::blocking_delay_us;
-use crate::adc::{Adc, AdcChannel, Instance, Resolution, SampleTime};
+use crate::adc::{Adc, AdcChannel, AnyAdcChannel, Instance, Resolution, RxDma, SampleTime, SealedAdcChannel};
+use crate::pac::adc::vals;
 use crate::peripherals::ADC1;
 use crate::time::Hertz;
 use crate::{Peri, rcc};
 
-mod ringbuffered_v2;
-pub use ringbuffered_v2::{RingBufferedAdc, Sequence};
+mod ringbuffered;
+pub use ringbuffered::RingBufferedAdc;
+
+fn clear_interrupt_flags(r: crate::pac::adc::Adc) {
+    r.sr().modify(|regs| {
+        regs.set_eoc(false);
+        regs.set_ovr(false);
+    });
+}
 
 /// Default VREF voltage used for sample conversion to millivolts.
 pub const VREF_DEFAULT_MV: u32 = 3300;
@@ -112,6 +123,98 @@ where
         }
     }
 
+    /// Configures the ADC to use a DMA ring buffer for continuous data acquisition.
+    ///
+    /// The `dma_buf` should be large enough to prevent DMA buffer overrun.
+    /// The length of the `dma_buf` should be a multiple of the ADC channel count.
+    /// For example, if 3 channels are measured, its length can be 3 * 40 = 120 measurements.
+    ///
+    /// `read` method is used to read out measurements from the DMA ring buffer, and its buffer should be exactly half of the `dma_buf` length.
+    /// It is critical to call `read` frequently to prevent DMA buffer overrun.
+    ///
+    /// [`read`]: #method.read
+    pub fn into_ring_buffered<'a>(
+        self,
+        dma: Peri<'d, impl RxDma<T>>,
+        dma_buf: &'d mut [u16],
+        sequence: impl ExactSizeIterator<Item = (&'a mut AnyAdcChannel<T>, SampleTime)>,
+    ) -> RingBufferedAdc<'d, T> {
+        assert!(!dma_buf.is_empty() && dma_buf.len() <= 0xFFFF);
+
+        T::regs().cr2().modify(|reg| {
+            reg.set_adon(true);
+        });
+
+        // Check the sequence is long enough
+        T::regs().sqr1().modify(|r| {
+            r.set_l((sequence.len() - 1).try_into().unwrap());
+        });
+
+        for (i, (channel, sample_time)) in sequence.enumerate() {
+            // Set this GPIO as an analog input.
+            channel.setup();
+
+            // Set the channel in the right sequence field.
+            T::regs().sqr3().modify(|w| w.set_sq(i, channel.channel()));
+
+            Self::set_channel_sample_time(channel.channel(), sample_time);
+        }
+
+        compiler_fence(Ordering::SeqCst);
+
+        let r = T::regs();
+
+        // Clear all interrupts
+        r.sr().modify(|regs| {
+            regs.set_eoc(false);
+            regs.set_ovr(false);
+            regs.set_strt(false);
+        });
+
+        r.cr1().modify(|w| {
+            // Enable interrupt for end of conversion
+            w.set_eocie(true);
+            // Enable interrupt for overrun
+            w.set_ovrie(true);
+            // Scanning converisons of multiple channels
+            w.set_scan(true);
+            // Continuous conversion mode
+            w.set_discen(false);
+        });
+
+        r.cr2().modify(|w| {
+            // Enable DMA mode
+            w.set_dma(true);
+            // Enable continuous conversions
+            w.set_cont(true);
+            // DMA requests are issues as long as DMA=1 and data are converted.
+            w.set_dds(vals::Dds::CONTINUOUS);
+            // EOC flag is set at the end of each conversion.
+            w.set_eocs(vals::Eocs::EACH_CONVERSION);
+        });
+
+        // Don't disable the clock
+        mem::forget(self);
+
+        RingBufferedAdc::new(dma, dma_buf)
+    }
+
+    pub(super) fn start() {
+        // Begin ADC conversions
+        T::regs().cr2().modify(|reg| {
+            reg.set_adon(true);
+            reg.set_swstart(true);
+        });
+    }
+
+    pub(super) fn stop() {
+        // Stop ADC
+        T::regs().cr2().modify(|reg| {
+            // Stop ADC
+            reg.set_swstart(false);
+        });
+    }
+
     pub fn set_sample_time(&mut self, sample_time: SampleTime) {
         self.sample_time = sample_time;
     }
@@ -198,6 +301,31 @@ where
             T::regs().smpr1().modify(|reg| reg.set_smp((ch - 10) as _, sample_time));
         }
     }
+
+    pub(super) fn teardown_adc() {
+        let r = T::regs();
+
+        // Stop ADC
+        r.cr2().modify(|reg| {
+            // Stop ADC
+            reg.set_swstart(false);
+            // Stop ADC
+            reg.set_adon(false);
+            // Stop DMA
+            reg.set_dma(false);
+        });
+
+        r.cr1().modify(|w| {
+            // Disable interrupt for end of conversion
+            w.set_eocie(false);
+            // Disable interrupt for overrun
+            w.set_ovrie(false);
+        });
+
+        clear_interrupt_flags(r);
+
+        compiler_fence(Ordering::SeqCst);
+    }
 }
 
 impl<'d, T: Instance> Drop for Adc<'d, T> {
diff --git a/embassy-stm32/src/adc/v3.rs b/embassy-stm32/src/adc/v3.rs
index e5b9a5d85..62c2da557 100644
--- a/embassy-stm32/src/adc/v3.rs
+++ b/embassy-stm32/src/adc/v3.rs
@@ -14,10 +14,10 @@ use super::{
 };
 
 #[cfg(any(adc_v3, adc_g0, adc_u0))]
-mod ringbuffered_v3;
+mod ringbuffered;
 
 #[cfg(any(adc_v3, adc_g0, adc_u0))]
-use ringbuffered_v3::RingBufferedAdc;
+use ringbuffered::RingBufferedAdc;
 
 use crate::dma::Transfer;
 use crate::{Peri, pac, rcc};
@@ -181,6 +181,38 @@ impl<'d, T: Instance> Adc<'d, T> {
         blocking_delay_us(1);
     }
 
+    #[cfg(any(adc_v3, adc_g0, adc_u0))]
+    pub(super) fn start() {
+        // Start adc conversion
+        T::regs().cr().modify(|reg| {
+            reg.set_adstart(true);
+        });
+    }
+
+    #[cfg(any(adc_v3, adc_g0, adc_u0))]
+    pub(super) fn stop() {
+        // Stop adc conversion
+        if T::regs().cr().read().adstart() && !T::regs().cr().read().addis() {
+            T::regs().cr().modify(|reg| {
+                reg.set_adstp(true);
+            });
+            while T::regs().cr().read().adstart() {}
+        }
+    }
+
+    #[cfg(any(adc_v3, adc_g0, adc_u0))]
+    pub(super) fn teardown_adc() {
+        //disable dma control
+        #[cfg(not(any(adc_g0, adc_u0)))]
+        T::regs().cfgr().modify(|reg| {
+            reg.set_dmaen(false);
+        });
+        #[cfg(any(adc_g0, adc_u0))]
+        T::regs().cfgr1().modify(|reg| {
+            reg.set_dmaen(false);
+        });
+    }
+
     /// Initialize the ADC leaving any analog clock at reset value.
     /// For G0 and WL, this is the async clock without prescaler.
     pub fn new(adc: Peri<'d, T>) -> Self {
diff --git a/examples/stm32f4/src/bin/adc_dma.rs b/examples/stm32f4/src/bin/adc_dma.rs
index c24f01753..f8da91336 100644
--- a/examples/stm32f4/src/bin/adc_dma.rs
+++ b/examples/stm32f4/src/bin/adc_dma.rs
@@ -4,7 +4,7 @@ use cortex_m::singleton;
 use defmt::*;
 use embassy_executor::Spawner;
 use embassy_stm32::Peripherals;
-use embassy_stm32::adc::{Adc, RingBufferedAdc, SampleTime, Sequence};
+use embassy_stm32::adc::{Adc, AdcChannel, RingBufferedAdc, SampleTime};
 use embassy_time::Instant;
 use {defmt_rtt as _, panic_probe as _};
 
@@ -15,7 +15,7 @@ async fn main(spawner: Spawner) {
 }
 
 #[embassy_executor::task]
-async fn adc_task(mut p: Peripherals) {
+async fn adc_task(p: Peripherals) {
     const ADC_BUF_SIZE: usize = 1024;
     let adc_data: &mut [u16; ADC_BUF_SIZE] = singleton!(ADCDAT : [u16; ADC_BUF_SIZE] = [0u16; ADC_BUF_SIZE]).unwrap();
     let adc_data2: &mut [u16; ADC_BUF_SIZE] = singleton!(ADCDAT2 : [u16; ADC_BUF_SIZE] = [0u16; ADC_BUF_SIZE]).unwrap();
@@ -23,13 +23,24 @@ async fn adc_task(mut p: Peripherals) {
     let adc = Adc::new(p.ADC1);
     let adc2 = Adc::new(p.ADC2);
 
-    let mut adc: RingBufferedAdc<embassy_stm32::peripherals::ADC1> = adc.into_ring_buffered(p.DMA2_CH0, adc_data);
-    let mut adc2: RingBufferedAdc<embassy_stm32::peripherals::ADC2> = adc2.into_ring_buffered(p.DMA2_CH2, adc_data2);
-
-    adc.set_sample_sequence(Sequence::One, &mut p.PA0, SampleTime::CYCLES112);
-    adc.set_sample_sequence(Sequence::Two, &mut p.PA2, SampleTime::CYCLES112);
-    adc2.set_sample_sequence(Sequence::One, &mut p.PA1, SampleTime::CYCLES112);
-    adc2.set_sample_sequence(Sequence::Two, &mut p.PA3, SampleTime::CYCLES112);
+    let mut adc: RingBufferedAdc<embassy_stm32::peripherals::ADC1> = adc.into_ring_buffered(
+        p.DMA2_CH0,
+        adc_data,
+        [
+            (&mut p.PA0.degrade_adc(), SampleTime::CYCLES112),
+            (&mut p.PA2.degrade_adc(), SampleTime::CYCLES112),
+        ]
+        .into_iter(),
+    );
+    let mut adc2: RingBufferedAdc<embassy_stm32::peripherals::ADC2> = adc2.into_ring_buffered(
+        p.DMA2_CH2,
+        adc_data2,
+        [
+            (&mut p.PA1.degrade_adc(), SampleTime::CYCLES112),
+            (&mut p.PA3.degrade_adc(), SampleTime::CYCLES112),
+        ]
+        .into_iter(),
+    );
 
     // Note that overrun is a big consideration in this implementation. Whatever task is running the adc.read() calls absolutely must circle back around
     // to the adc.read() call before the DMA buffer is wrapped around > 1 time. At this point, the overrun is so significant that the context of