STM32 DAC: Rework DAC driver, support all families.

embassy-stm32/build.rs

@@ -996,8 +996,8 @@ fn main() {
         // SDMMCv1 uses the same channel for both directions, so just implement for RX
         (("sdmmc", "RX"), quote!(crate::sdmmc::SdmmcDma)),
         (("quadspi", "QUADSPI"), quote!(crate::qspi::QuadDma)),
-        (("dac", "CH1"), quote!(crate::dac::DmaCh1)),
+        (("dac", "CH1"), quote!(crate::dac::DacDma1)),
-        (("dac", "CH2"), quote!(crate::dac::DmaCh2)),
+        (("dac", "CH2"), quote!(crate::dac::DacDma2)),
     ]
     .into();
 

embassy-stm32/src/dac/mod.rs

@@ -1,10 +1,11 @@
+//! Provide access to the STM32 digital-to-analog converter (DAC).
 #![macro_use]
 
-//! Provide access to the STM32 digital-to-analog converter (DAC).
 use core::marker::PhantomData;
 
 use embassy_hal_internal::{into_ref, PeripheralRef};
 
+use crate::dma::NoDma;
 #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
 use crate::pac::dac;
 use crate::rcc::RccPeripheral;
@@ -13,6 +14,7 @@ use crate::{peripherals, Peripheral};
 mod tsel;
 pub use tsel::TriggerSel;
 
+/// Operating mode for DAC channel
 #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
@@ -56,32 +58,9 @@ impl Mode {
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
-/// Custom Errors
+/// Single 8 or 12 bit value that can be output by the DAC.
-pub enum Error {
+///
-    UnconfiguredChannel,
+/// 12-bit values outside the permitted range are silently truncated.
-    InvalidValue,
-}
-
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-/// DAC Channels
-pub enum Channel {
-    Ch1,
-    Ch2,
-}
-
-impl Channel {
-    const fn index(&self) -> usize {
-        match self {
-            Channel::Ch1 => 0,
-            Channel::Ch2 => 1,
-        }
-    }
-}
-
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-#[cfg_attr(feature = "defmt", derive(defmt::Format))]
-/// Single 8 or 12 bit value that can be output by the DAC
 pub enum Value {
     // 8 bit value
     Bit8(u8),
@@ -93,7 +72,21 @@ pub enum Value {
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
-/// Array variant of [`Value`]
+/// Dual 8 or 12 bit values that can be output by the DAC channels 1 and 2 simultaneously.
+///
+/// 12-bit values outside the permitted range are silently truncated.
+pub enum DualValue {
+    // 8 bit value
+    Bit8(u8, u8),
+    // 12 bit value stored in a u16, left-aligned
+    Bit12Left(u16, u16),
+    // 12 bit value stored in a u16, right-aligned
+    Bit12Right(u16, u16),
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+/// Array variant of [`Value`].
 pub enum ValueArray<'a> {
     // 8 bit values
     Bit8(&'a [u8]),
@@ -102,266 +95,206 @@ pub enum ValueArray<'a> {
     // 12 bit values stored in a u16, right-aligned
     Bit12Right(&'a [u16]),
 }
-/// Provide common functions for DAC channels
-pub trait DacChannel<T: Instance, Tx> {
-    const CHANNEL: Channel;
 
-    /// Enable trigger of the given channel
+/// Driver for a single DAC channel.
-    fn set_trigger_enable(&mut self, on: bool) -> Result<(), Error> {
-        T::regs().cr().modify(|reg| {
-            reg.set_ten(Self::CHANNEL.index(), on);
-        });
-        Ok(())
-    }
-
-    /// Set mode register of the given channel
-    #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
-    fn set_channel_mode(&mut self, mode: Mode) -> Result<(), Error> {
-        T::regs().mcr().modify(|reg| {
-            reg.set_mode(Self::CHANNEL.index(), mode.mode());
-        });
-        Ok(())
-    }
-
-    /// Set enable register of the given channel
-    fn set_channel_enable(&mut self, on: bool) -> Result<(), Error> {
-        T::regs().cr().modify(|reg| {
-            reg.set_en(Self::CHANNEL.index(), on);
-        });
-        Ok(())
-    }
-
-    /// Enable the DAC channel `ch`
-    fn enable_channel(&mut self) -> Result<(), Error> {
-        self.set_channel_enable(true)
-    }
-
-    /// Disable the DAC channel `ch`
-    fn disable_channel(&mut self) -> Result<(), Error> {
-        self.set_channel_enable(false)
-    }
-
-    /// Perform a software trigger on `ch`
-    fn trigger(&mut self) {
-        T::regs().swtrigr().write(|reg| {
-            reg.set_swtrig(Self::CHANNEL.index(), true);
-        });
-    }
-
-    /// Set a value to be output by the DAC on trigger.
 ///
-    /// The `value` is written to the corresponding "data holding register".
+/// If you want to use both channels, either together or independently,
-    fn set(&mut self, value: Value) -> Result<(), Error> {
+/// create a [`Dac`] first and use it to access each channel.
-        match value {
+pub struct DacChannel<'d, T: Instance, const N: u8, DMA = NoDma> {
-            Value::Bit8(v) => T::regs().dhr8r(Self::CHANNEL.index()).write(|reg| reg.set_dhr(v)),
-            Value::Bit12Left(v) => T::regs().dhr12l(Self::CHANNEL.index()).write(|reg| reg.set_dhr(v)),
-            Value::Bit12Right(v) => T::regs().dhr12r(Self::CHANNEL.index()).write(|reg| reg.set_dhr(v)),
-        }
-        Ok(())
-    }
-}
-
-/// Hold two DAC channels
-///
-/// Note: This consumes the DAC `Instance` only once, allowing to get both channels simultaneously.
-///
-/// # Example for obtaining both DAC channels
-///
-/// ```ignore
-/// // DMA channels and pins may need to be changed for your controller
-/// let (dac_ch1, dac_ch2) =
-///     embassy_stm32::dac::Dac::new(p.DAC1, p.DMA1_CH3, p.DMA1_CH4, p.PA4, p.PA5).split();
-/// ```
-pub struct Dac<'d, T: Instance, TxCh1, TxCh2> {
-    ch1: DacCh1<'d, T, TxCh1>,
-    ch2: DacCh2<'d, T, TxCh2>,
-}
-
-/// DAC CH1
-///
-/// Note: This consumes the DAC `Instance`. Use [`Dac::new`] to get both channels simultaneously.
-pub struct DacCh1<'d, T: Instance, Tx> {
-    /// To consume T
-    _peri: PeripheralRef<'d, T>,
-    #[allow(unused)] // For chips whose DMA is not (yet) supported
-    dma: PeripheralRef<'d, Tx>,
-}
-
-/// DAC CH2
-///
-/// Note: This consumes the DAC `Instance`. Use [`Dac::new`] to get both channels simultaneously.
-pub struct DacCh2<'d, T: Instance, Tx> {
-    /// Instead of PeripheralRef to consume T
     phantom: PhantomData<&'d mut T>,
-    #[allow(unused)] // For chips whose DMA is not (yet) supported
+    #[allow(unused)]
-    dma: PeripheralRef<'d, Tx>,
+    dma: PeripheralRef<'d, DMA>,
 }
 
-impl<'d, T: Instance, Tx> DacCh1<'d, T, Tx> {
+pub type DacCh1<'d, T, DMA = NoDma> = DacChannel<'d, T, 1, DMA>;
-    /// Obtain DAC CH1
+pub type DacCh2<'d, T, DMA = NoDma> = DacChannel<'d, T, 2, DMA>;
-    pub fn new(
-        peri: impl Peripheral<P = T> + 'd,
-        dma: impl Peripheral<P = Tx> + 'd,
-        pin: impl Peripheral<P = impl DacPin<T, 1>> + crate::gpio::sealed::Pin + 'd,
-    ) -> Self {
-        pin.set_as_analog();
-        into_ref!(peri, dma);
-        T::enable_and_reset();
 
-        let mut dac = Self { _peri: peri, dma };
+impl<'d, T: Instance, const N: u8, DMA> DacChannel<'d, T, N, DMA> {
+    const IDX: usize = (N - 1) as usize;
 
-        // Configure each activated channel. All results can be `unwrap`ed since they
+    /// Create a new `DacChannel` instance, consuming the underlying DAC peripheral.
-        // will only error if the channel is not configured (i.e. ch1, ch2 are false)
-        #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
-        dac.set_channel_mode(Mode::NormalExternalBuffered).unwrap();
-        dac.enable_channel().unwrap();
-        dac.set_trigger_enable(true).unwrap();
-
-        dac
-    }
-
-    /// Select a new trigger for this channel
     ///
-    /// **Important**: This disables the channel!
+    /// If you're not using DMA, pass [`dma::NoDma`] for the `dma` argument.
-    pub fn select_trigger(&mut self, trigger: TriggerSel) -> Result<(), Error> {
-        unwrap!(self.disable_channel());
-        T::regs().cr().modify(|reg| {
-            reg.set_tsel(0, trigger.tsel());
-        });
-        Ok(())
-    }
-
-    /// Write `data` to the DAC CH1 via DMA.
     ///
-    /// To prevent delays/glitches when outputting a periodic waveform, the `circular` flag can be set.
+    /// The channel is enabled on creation and begins to drive the output pin.
-    /// This will configure a circular DMA transfer that periodically outputs the `data`.
+    /// Note that some methods, such as `set_trigger()` and `set_mode()`, will
-    /// Note that for performance reasons in circular mode the transfer complete interrupt is disabled.
+    /// disable the channel; you must re-enable it with `enable()`.
     ///
-    /// **Important:** Channel 1 has to be configured for the DAC instance!
+    /// By default, triggering is disabled, but it can be enabled using
-    #[cfg(not(gpdma))]
+    /// [`DacChannel::set_trigger()`].
-    pub async fn write(&mut self, data: ValueArray<'_>, circular: bool) -> Result<(), Error>
-    where
-        Tx: DmaCh1<T>,
-    {
-        let channel = Channel::Ch1.index();
-        debug!("Writing to channel {}", channel);
-
-        // Enable DAC and DMA
-        T::regs().cr().modify(|w| {
-            w.set_en(channel, true);
-            w.set_dmaen(channel, true);
-        });
-
-        let tx_request = self.dma.request();
-        let dma_channel = &mut self.dma;
-
-        let tx_options = crate::dma::TransferOptions {
-            circular,
-            half_transfer_ir: false,
-            complete_transfer_ir: !circular,
-            ..Default::default()
-        };
-
-        // Initiate the correct type of DMA transfer depending on what data is passed
-        let tx_f = match data {
-            ValueArray::Bit8(buf) => unsafe {
-                crate::dma::Transfer::new_write(
-                    dma_channel,
-                    tx_request,
-                    buf,
-                    T::regs().dhr8r(channel).as_ptr() as *mut u8,
-                    tx_options,
-                )
-            },
-            ValueArray::Bit12Left(buf) => unsafe {
-                crate::dma::Transfer::new_write(
-                    dma_channel,
-                    tx_request,
-                    buf,
-                    T::regs().dhr12l(channel).as_ptr() as *mut u16,
-                    tx_options,
-                )
-            },
-            ValueArray::Bit12Right(buf) => unsafe {
-                crate::dma::Transfer::new_write(
-                    dma_channel,
-                    tx_request,
-                    buf,
-                    T::regs().dhr12r(channel).as_ptr() as *mut u16,
-                    tx_options,
-                )
-            },
-        };
-
-        tx_f.await;
-
-        // finish dma
-        // TODO: Do we need to check any status registers here?
-        T::regs().cr().modify(|w| {
-            // Disable the DAC peripheral
-            w.set_en(channel, false);
-            // Disable the DMA. TODO: Is this necessary?
-            w.set_dmaen(channel, false);
-        });
-
-        Ok(())
-    }
-}
-
-impl<'d, T: Instance, Tx> DacCh2<'d, T, Tx> {
-    /// Obtain DAC CH2
     pub fn new(
         _peri: impl Peripheral<P = T> + 'd,
-        dma: impl Peripheral<P = Tx> + 'd,
+        dma: impl Peripheral<P = DMA> + 'd,
-        pin: impl Peripheral<P = impl DacPin<T, 2>> + crate::gpio::sealed::Pin + 'd,
+        pin: impl Peripheral<P = impl DacPin<T, N> + crate::gpio::sealed::Pin> + 'd,
     ) -> Self {
+        into_ref!(dma, pin);
         pin.set_as_analog();
-        into_ref!(_peri, dma);
         T::enable_and_reset();
-
         let mut dac = Self {
             phantom: PhantomData,
             dma,
         };
-
+        #[cfg(any(dac_v5, dac_v6, dac_v7))]
-        // Configure each activated channel. All results can be `unwrap`ed since they
+        dac.set_hfsel();
-        // will only error if the channel is not configured (i.e. ch1, ch2 are false)
+        dac.enable();
-        #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
-        dac.set_channel_mode(Mode::NormalExternalBuffered).unwrap();
-        dac.enable_channel().unwrap();
-        dac.set_trigger_enable(true).unwrap();
-
         dac
     }
 
-    /// Select a new trigger for this channel
+    /// Create a new `DacChannel` instance where the external output pin is not used,
-    pub fn select_trigger(&mut self, trigger: TriggerSel) -> Result<(), Error> {
+    /// so the DAC can only be used to generate internal signals.
-        unwrap!(self.disable_channel());
+    /// The GPIO pin is therefore available to be used for other functions.
-        T::regs().cr().modify(|reg| {
+    ///
-            reg.set_tsel(1, trigger.tsel());
+    /// The channel is set to [`Mode::NormalInternalUnbuffered`] and enabled on creation.
-        });
+    /// Note that some methods, such as `set_trigger()` and `set_mode()`, will disable the
-        Ok(())
+    /// channel; you must re-enable it with `enable()`.
+    ///
+    /// If you're not using DMA, pass [`dma::NoDma`] for the `dma` argument.
+    ///
+    /// By default, triggering is disabled, but it can be enabled using
+    /// [`DacChannel::set_trigger()`].
+    #[cfg(all(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7), not(any(stm32h56x, stm32h57x))))]
+    pub fn new_internal(_peri: impl Peripheral<P = T> + 'd, dma: impl Peripheral<P = DMA> + 'd) -> Self {
+        into_ref!(dma);
+        T::enable_and_reset();
+        let mut dac = Self {
+            phantom: PhantomData,
+            dma,
+        };
+        #[cfg(any(dac_v5, dac_v6, dac_v7))]
+        dac.set_hfsel();
+        dac.set_mode(Mode::NormalInternalUnbuffered);
+        dac.enable();
+        dac
     }
 
-    /// Write `data` to the DAC CH2 via DMA.
+    /// Enable or disable this channel.
-    ///
+    pub fn set_enable(&mut self, on: bool) {
-    /// To prevent delays/glitches when outputting a periodic waveform, the `circular` flag can be set.
+        critical_section::with(|_| {
-    /// This will configure a circular DMA transfer that periodically outputs the `data`.
+            T::regs().cr().modify(|reg| {
-    /// Note that for performance reasons in circular mode the transfer complete interrupt is disabled.
+                reg.set_en(Self::IDX, on);
-    ///
+            });
-    /// **Important:** Channel 2 has to be configured for the DAC instance!
+        });
-    #[cfg(not(gpdma))]
+    }
-    pub async fn write(&mut self, data: ValueArray<'_>, circular: bool) -> Result<(), Error>
-    where
-        Tx: DmaCh2<T>,
-    {
-        let channel = Channel::Ch2.index();
-        debug!("Writing to channel {}", channel);
 
+    /// Enable this channel.
+    pub fn enable(&mut self) {
+        self.set_enable(true)
+    }
+
+    /// Disable this channel.
+    pub fn disable(&mut self) {
+        self.set_enable(false)
+    }
+
+    /// Set the trigger source for this channel.
+    ///
+    /// This method disables the channel, so you may need to re-enable afterwards.
+    pub fn set_trigger(&mut self, source: TriggerSel) {
+        critical_section::with(|_| {
+            T::regs().cr().modify(|reg| {
+                reg.set_en(Self::IDX, false);
+                reg.set_tsel(Self::IDX, source as u8);
+            });
+        });
+    }
+
+    /// Enable or disable triggering for this channel.
+    pub fn set_triggering(&mut self, on: bool) {
+        critical_section::with(|_| {
+            T::regs().cr().modify(|reg| {
+                reg.set_ten(Self::IDX, on);
+            });
+        });
+    }
+
+    /// Software trigger this channel.
+    pub fn trigger(&mut self) {
+        T::regs().swtrigr().write(|reg| {
+            reg.set_swtrig(Self::IDX, true);
+        });
+    }
+
+    /// Set mode of this channel.
+    ///
+    /// This method disables the channel, so you may need to re-enable afterwards.
+    #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
+    pub fn set_mode(&mut self, mode: Mode) {
+        critical_section::with(|_| {
+            T::regs().cr().modify(|reg| {
+                reg.set_en(Self::IDX, false);
+            });
+            T::regs().mcr().modify(|reg| {
+                reg.set_mode(Self::IDX, mode.mode());
+            });
+        });
+    }
+
+    /// Write a new value to this channel.
+    ///
+    /// If triggering is not enabled, the new value is immediately output; otherwise,
+    /// it will be output after the next trigger.
+    pub fn set(&mut self, value: Value) {
+        match value {
+            Value::Bit8(v) => T::regs().dhr8r(Self::IDX).write(|reg| reg.set_dhr(v)),
+            Value::Bit12Left(v) => T::regs().dhr12l(Self::IDX).write(|reg| reg.set_dhr(v)),
+            Value::Bit12Right(v) => T::regs().dhr12r(Self::IDX).write(|reg| reg.set_dhr(v)),
+        }
+    }
+
+    /// Read the current output value of the DAC.
+    pub fn read(&self) -> u16 {
+        T::regs().dor(Self::IDX).read().dor()
+    }
+
+    /// Set HFSEL as appropriate for the current peripheral clock frequency.
+    #[cfg(dac_v5)]
+    fn set_hfsel(&mut self) {
+        if T::frequency() >= crate::time::mhz(80) {
+            critical_section::with(|_| {
+                T::regs().cr().modify(|reg| {
+                    reg.set_hfsel(true);
+                });
+            });
+        }
+    }
+
+    /// Set HFSEL as appropriate for the current peripheral clock frequency.
+    #[cfg(any(dac_v6, dac_v7))]
+    fn set_hfsel(&mut self) {
+        if T::frequency() >= crate::time::mhz(160) {
+            critical_section::with(|_| {
+                T::regs().mcr().modify(|reg| {
+                    reg.set_hfsel(0b10);
+                });
+            });
+        } else if T::frequency() >= crate::time::mhz(80) {
+            critical_section::with(|_| {
+                T::regs().mcr().modify(|reg| {
+                    reg.set_hfsel(0b01);
+                });
+            });
+        }
+    }
+}
+
+macro_rules! impl_dma_methods {
+    ($n:literal, $trait:ident) => {
+        impl<'d, T: Instance, DMA> DacChannel<'d, T, $n, DMA>
+        where
+            DMA: $trait<T>,
+        {
+            /// Write `data` to this channel via DMA.
+            ///
+            /// To prevent delays or glitches when outputing a periodic waveform, the `circular`
+            /// flag can be set. This configures a circular DMA transfer that continually outputs
+            /// `data`. Note that for performance reasons in circular mode the transfer-complete
+            /// interrupt is disabled.
+            #[cfg(not(gpdma))]
+            pub async fn write(&mut self, data: ValueArray<'_>, circular: bool) {
                 // Enable DAC and DMA
                 T::regs().cr().modify(|w| {
-            w.set_en(channel, true);
+                    w.set_en(Self::IDX, true);
-            w.set_dmaen(channel, true);
+                    w.set_dmaen(Self::IDX, true);
                 });
 
                 let tx_request = self.dma.request();
@@ -381,7 +314,7 @@ impl<'d, T: Instance, Tx> DacCh2<'d, T, Tx> {
                             dma_channel,
                             tx_request,
                             buf,
-                    T::regs().dhr8r(channel).as_ptr() as *mut u8,
+                            T::regs().dhr8r(Self::IDX).as_ptr() as *mut u8,
                             tx_options,
                         )
                     },
@@ -390,7 +323,7 @@ impl<'d, T: Instance, Tx> DacCh2<'d, T, Tx> {
                             dma_channel,
                             tx_request,
                             buf,
-                    T::regs().dhr12l(channel).as_ptr() as *mut u16,
+                            T::regs().dhr12l(Self::IDX).as_ptr() as *mut u16,
                             tx_options,
                         )
                     },
@@ -399,7 +332,7 @@ impl<'d, T: Instance, Tx> DacCh2<'d, T, Tx> {
                             dma_channel,
                             tx_request,
                             buf,
-                    T::regs().dhr12r(channel).as_ptr() as *mut u16,
+                            T::regs().dhr12r(Self::IDX).as_ptr() as *mut u16,
                             tx_options,
                         )
                     },
@@ -407,95 +340,150 @@ impl<'d, T: Instance, Tx> DacCh2<'d, T, Tx> {
 
                 tx_f.await;
 
-        // finish dma
-        // TODO: Do we need to check any status registers here?
                 T::regs().cr().modify(|w| {
-            // Disable the DAC peripheral
+                    w.set_en(Self::IDX, false);
-            w.set_en(channel, false);
+                    w.set_dmaen(Self::IDX, false);
-            // Disable the DMA. TODO: Is this necessary?
-            w.set_dmaen(channel, false);
                 });
+            }
+        }
+    };
+}
 
-        Ok(())
+impl_dma_methods!(1, DacDma1);
+impl_dma_methods!(2, DacDma1);
+
+impl<'d, T: Instance, const N: u8, DMA> Drop for DacChannel<'d, T, N, DMA> {
+    fn drop(&mut self) {
+        T::disable();
     }
 }
 
-impl<'d, T: Instance, TxCh1, TxCh2> Dac<'d, T, TxCh1, TxCh2> {
+/// DAC driver.
-    /// Create a new DAC instance with both channels.
 ///
-    /// This is used to obtain two independent channels via `split()` for use e.g. with DMA.
+/// Use this struct when you want to use both channels, either together or independently.
+///
+/// # Example
+///
+/// ```ignore
+/// // Pins may need to be changed for your specific device.
+/// let (dac_ch1, dac_ch2) = embassy_stm32::dac::Dac::new(p.DAC, NoDma, NoDma, p.PA4, p.PA5).split();
+/// ```
+pub struct Dac<'d, T: Instance, DMACh1 = NoDma, DMACh2 = NoDma> {
+    ch1: DacChannel<'d, T, 1, DMACh1>,
+    ch2: DacChannel<'d, T, 2, DMACh2>,
+}
+
+impl<'d, T: Instance, DMACh1, DMACh2> Dac<'d, T, DMACh1, DMACh2> {
+    /// Create a new `Dac` instance, consuming the underlying DAC peripheral.
+    ///
+    /// This struct allows you to access both channels of the DAC, where available. You can either
+    /// call `split()` to obtain separate `DacChannel`s, or use methods on `Dac` to use
+    /// the two channels together.
+    ///
+    /// The channels are enabled on creation and begins to drive their output pins.
+    /// Note that some methods, such as `set_trigger()` and `set_mode()`, will
+    /// disable the channel; you must re-enable them with `enable()`.
+    ///
+    /// By default, triggering is disabled, but it can be enabled using the `set_trigger()`
+    /// method on the underlying channels.
     pub fn new(
-        peri: impl Peripheral<P = T> + 'd,
+        _peri: impl Peripheral<P = T> + 'd,
-        dma_ch1: impl Peripheral<P = TxCh1> + 'd,
+        dma_ch1: impl Peripheral<P = DMACh1> + 'd,
-        dma_ch2: impl Peripheral<P = TxCh2> + 'd,
+        dma_ch2: impl Peripheral<P = DMACh2> + 'd,
-        pin_ch1: impl Peripheral<P = impl DacPin<T, 1>> + crate::gpio::sealed::Pin + 'd,
+        pin_ch1: impl Peripheral<P = impl DacPin<T, 1> + crate::gpio::sealed::Pin> + 'd,
-        pin_ch2: impl Peripheral<P = impl DacPin<T, 2>> + crate::gpio::sealed::Pin + 'd,
+        pin_ch2: impl Peripheral<P = impl DacPin<T, 2> + crate::gpio::sealed::Pin> + 'd,
     ) -> Self {
+        into_ref!(dma_ch1, dma_ch2, pin_ch1, pin_ch2);
         pin_ch1.set_as_analog();
         pin_ch2.set_as_analog();
-        into_ref!(peri, dma_ch1, dma_ch2);
+        // Enable twice to increment the DAC refcount for each channel.
         T::enable_and_reset();
-
+        T::enable_and_reset();
-        let mut dac_ch1 = DacCh1 {
+        Self {
-            _peri: peri,
+            ch1: DacCh1 {
+                phantom: PhantomData,
                 dma: dma_ch1,
-        };
+            },
-
+            ch2: DacCh2 {
-        let mut dac_ch2 = DacCh2 {
                 phantom: PhantomData,
                 dma: dma_ch2,
-        };
+            },
-
+        }
-        // Configure each activated channel. All results can be `unwrap`ed since they
+    }
-        // will only error if the channel is not configured (i.e. ch1, ch2 are false)
-        #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v73))]
-        dac_ch1.set_channel_mode(Mode::NormalExternalBuffered).unwrap();
-        dac_ch1.enable_channel().unwrap();
-        dac_ch1.set_trigger_enable(true).unwrap();
-
-        #[cfg(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7))]
-        dac_ch2.set_channel_mode(Mode::NormalExternalBuffered).unwrap();
-        dac_ch2.enable_channel().unwrap();
-        dac_ch2.set_trigger_enable(true).unwrap();
 
+    /// Create a new `Dac` instance where the external output pins are not used,
+    /// so the DAC can only be used to generate internal signals but the GPIO
+    /// pins remain available for other functions.
+    ///
+    /// This struct allows you to access both channels of the DAC, where available. You can either
+    /// call `split()` to obtain separate `DacChannel`s, or use methods on `Dac` to use the two
+    /// channels together.
+    ///
+    /// The channels are set to [`Mode::NormalInternalUnbuffered`] and enabled on creation.
+    /// Note that some methods, such as `set_trigger()` and `set_mode()`, will disable the
+    /// channel; you must re-enable them with `enable()`.
+    ///
+    /// By default, triggering is disabled, but it can be enabled using the `set_trigger()`
+    /// method on the underlying channels.
+    #[cfg(all(any(dac_v3, dac_v4, dac_v5, dac_v6, dac_v7), not(any(stm32h56x, stm32h57x))))]
+    pub fn new_internal(
+        _peri: impl Peripheral<P = T> + 'd,
+        dma_ch1: impl Peripheral<P = DMACh1> + 'd,
+        dma_ch2: impl Peripheral<P = DMACh2> + 'd,
+    ) -> Self {
+        into_ref!(dma_ch1, dma_ch2);
+        // Enable twice to increment the DAC refcount for each channel.
+        T::enable_and_reset();
+        T::enable_and_reset();
         Self {
-            ch1: dac_ch1,
+            ch1: DacCh1 {
-            ch2: dac_ch2,
+                phantom: PhantomData,
+                dma: dma_ch1,
+            },
+            ch2: DacCh2 {
+                phantom: PhantomData,
+                dma: dma_ch2,
+            },
         }
     }
 
-    /// Split the DAC into CH1 and CH2 for independent use.
+    /// Split this `Dac` into separate channels.
-    pub fn split(self) -> (DacCh1<'d, T, TxCh1>, DacCh2<'d, T, TxCh2>) {
+    ///
+    /// You can access and move the channels around separately after splitting.
+    pub fn split(self) -> (DacCh1<'d, T, DMACh1>, DacCh2<'d, T, DMACh2>) {
         (self.ch1, self.ch2)
     }
 
-    /// Get mutable reference to CH1
+    /// Temporarily access channel 1.
-    pub fn ch1_mut(&mut self) -> &mut DacCh1<'d, T, TxCh1> {
+    pub fn ch1(&mut self) -> &mut DacCh1<'d, T, DMACh1> {
         &mut self.ch1
     }
 
-    /// Get mutable reference to CH2
+    /// Temporarily access channel 2.
-    pub fn ch2_mut(&mut self) -> &mut DacCh2<'d, T, TxCh2> {
+    pub fn ch2(&mut self) -> &mut DacCh2<'d, T, DMACh2> {
         &mut self.ch2
     }
 
-    /// Get reference to CH1
+    /// Simultaneously update channels 1 and 2 with a new value.
-    pub fn ch1(&mut self) -> &DacCh1<'d, T, TxCh1> {
+    ///
-        &self.ch1
+    /// If triggering is not enabled, the new values are immediately output;
-    }
+    /// otherwise, they will be output after the next trigger.
-
+    pub fn set(&mut self, values: DualValue) {
-    /// Get reference to CH2
+        match values {
-    pub fn ch2(&mut self) -> &DacCh2<'d, T, TxCh2> {
+            DualValue::Bit8(v1, v2) => T::regs().dhr8rd().write(|reg| {
-        &self.ch2
+                reg.set_dhr(0, v1);
+                reg.set_dhr(1, v2);
+            }),
+            DualValue::Bit12Left(v1, v2) => T::regs().dhr12ld().write(|reg| {
+                reg.set_dhr(0, v1);
+                reg.set_dhr(1, v2);
+            }),
+            DualValue::Bit12Right(v1, v2) => T::regs().dhr12rd().write(|reg| {
+                reg.set_dhr(0, v1);
+                reg.set_dhr(1, v2);
+            }),
         }
     }
-
-impl<'d, T: Instance, Tx> DacChannel<T, Tx> for DacCh1<'d, T, Tx> {
-    const CHANNEL: Channel = Channel::Ch1;
-}
-
-impl<'d, T: Instance, Tx> DacChannel<T, Tx> for DacCh2<'d, T, Tx> {
-    const CHANNEL: Channel = Channel::Ch2;
 }
 
 pub(crate) mod sealed {
@@ -505,8 +493,8 @@ pub(crate) mod sealed {
 }
 
 pub trait Instance: sealed::Instance + RccPeripheral + 'static {}
-dma_trait!(DmaCh1, Instance);
+dma_trait!(DacDma1, Instance);
-dma_trait!(DmaCh2, Instance);
+dma_trait!(DacDma2, Instance);
 
 /// Marks a pin that can be used with the DAC
 pub trait DacPin<T: Instance, const C: u8>: crate::gpio::Pin + 'static {}
@@ -521,12 +509,14 @@ foreach_peripheral!(
             }
 
             fn enable_and_reset_with_cs(_cs: critical_section::CriticalSection) {
+                // TODO: Increment refcount?
                 crate::pac::RCC.apb1lrstr().modify(|w| w.set_dac12rst(true));
                 crate::pac::RCC.apb1lrstr().modify(|w| w.set_dac12rst(false));
                 crate::pac::RCC.apb1lenr().modify(|w| w.set_dac12en(true));
             }
 
             fn disable_with_cs(_cs: critical_section::CriticalSection) {
+                // TODO: Decrement refcount?
                 crate::pac::RCC.apb1lenr().modify(|w| w.set_dac12en(false))
             }
         }

examples/stm32f4/src/bin/dac.rs

@@ -4,7 +4,7 @@
 
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::dac::{DacCh1, DacChannel, Value};
+use embassy_stm32::dac::{DacCh1, Value};
 use embassy_stm32::dma::NoDma;
 use {defmt_rtt as _, panic_probe as _};
 
@@ -14,11 +14,10 @@ async fn main(_spawner: Spawner) -> ! {
     info!("Hello World, dude!");
 
     let mut dac = DacCh1::new(p.DAC, NoDma, p.PA4);
-    unwrap!(dac.set_trigger_enable(false));
 
     loop {
         for v in 0..=255 {
-            unwrap!(dac.set(Value::Bit8(to_sine_wave(v))));
+            dac.set(Value::Bit8(to_sine_wave(v)));
         }
     }
 }

examples/stm32h7/src/bin/dac.rs

@@ -4,7 +4,7 @@
 
 use cortex_m_rt::entry;
 use defmt::*;
-use embassy_stm32::dac::{DacCh1, DacChannel, Value};
+use embassy_stm32::dac::{DacCh1, Value};
 use embassy_stm32::dma::NoDma;
 use embassy_stm32::Config;
 use {defmt_rtt as _, panic_probe as _};
@@ -46,11 +46,10 @@ fn main() -> ! {
     let p = embassy_stm32::init(config);
 
     let mut dac = DacCh1::new(p.DAC1, NoDma, p.PA4);
-    unwrap!(dac.set_trigger_enable(false));
 
     loop {
         for v in 0..=255 {
-            unwrap!(dac.set(Value::Bit8(to_sine_wave(v))));
+            dac.set(Value::Bit8(to_sine_wave(v)));
         }
     }
 }

examples/stm32h7/src/bin/dac_dma.rs

@@ -4,21 +4,15 @@
 
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::dac::{DacChannel, ValueArray};
+use embassy_stm32::dac::{DacCh1, DacCh2, ValueArray};
 use embassy_stm32::pac::timer::vals::{Mms, Opm};
-use embassy_stm32::peripherals::{TIM6, TIM7};
+use embassy_stm32::peripherals::{DAC1, DMA1_CH3, DMA1_CH4, TIM6, TIM7};
 use embassy_stm32::rcc::low_level::RccPeripheral;
 use embassy_stm32::time::Hertz;
 use embassy_stm32::timer::low_level::Basic16bitInstance;
 use micromath::F32Ext;
 use {defmt_rtt as _, panic_probe as _};
 
-pub type Dac1Type =
-    embassy_stm32::dac::DacCh1<'static, embassy_stm32::peripherals::DAC1, embassy_stm32::peripherals::DMA1_CH3>;
-
-pub type Dac2Type =
-    embassy_stm32::dac::DacCh2<'static, embassy_stm32::peripherals::DAC1, embassy_stm32::peripherals::DMA1_CH4>;
-
 #[embassy_executor::main]
 async fn main(spawner: Spawner) {
     let mut config = embassy_stm32::Config::default();
@@ -63,7 +57,7 @@ async fn main(spawner: Spawner) {
 }
 
 #[embassy_executor::task]
-async fn dac_task1(mut dac: Dac1Type) {
+async fn dac_task1(mut dac: DacCh1<'static, DAC1, DMA1_CH3>) {
     let data: &[u8; 256] = &calculate_array::<256>();
 
     info!("TIM6 frequency is {}", TIM6::frequency());
@@ -77,8 +71,9 @@ async fn dac_task1(mut dac: Dac1Type) {
         error!("Reload value {} below threshold!", reload);
     }
 
-    dac.select_trigger(embassy_stm32::dac::TriggerSel::Tim6).unwrap();
+    dac.set_trigger(embassy_stm32::dac::TriggerSel::Tim6);
-    dac.enable_channel().unwrap();
+    dac.set_triggering(true);
+    dac.enable();
 
     TIM6::enable_and_reset();
     TIM6::regs().arr().modify(|w| w.set_arr(reload as u16 - 1));
@@ -100,14 +95,12 @@ async fn dac_task1(mut dac: Dac1Type) {
     // Loop technically not necessary if DMA circular mode is enabled
     loop {
         info!("Loop DAC1");
-        if let Err(e) = dac.write(ValueArray::Bit8(data), true).await {
+        dac.write(ValueArray::Bit8(data), true).await;
-            error!("Could not write to dac: {}", e);
-        }
     }
 }
 
 #[embassy_executor::task]
-async fn dac_task2(mut dac: Dac2Type) {
+async fn dac_task2(mut dac: DacCh2<'static, DAC1, DMA1_CH4>) {
     let data: &[u8; 256] = &calculate_array::<256>();
 
     info!("TIM7 frequency is {}", TIM7::frequency());
@@ -127,7 +120,9 @@ async fn dac_task2(mut dac: Dac2Type) {
         w.set_cen(true);
     });
 
-    dac.select_trigger(embassy_stm32::dac::TriggerSel::Tim7).unwrap();
+    dac.set_trigger(embassy_stm32::dac::TriggerSel::Tim7);
+    dac.set_triggering(true);
+    dac.enable();
 
     debug!(
         "TIM7 Frequency {}, Target Frequency {}, Reload {}, Reload as u16 {}, Samples {}",
@@ -138,9 +133,7 @@ async fn dac_task2(mut dac: Dac2Type) {
         data.len()
     );
 
-    if let Err(e) = dac.write(ValueArray::Bit8(data), true).await {
+    dac.write(ValueArray::Bit8(data), true).await;
-        error!("Could not write to dac: {}", e);
-    }
 }
 
 fn to_sine_wave(v: u8) -> u8 {

examples/stm32l4/src/bin/dac.rs

@@ -3,7 +3,7 @@
 #![feature(type_alias_impl_trait)]
 
 use defmt::*;
-use embassy_stm32::dac::{DacCh1, DacChannel, Value};
+use embassy_stm32::dac::{DacCh1, Value};
 use embassy_stm32::dma::NoDma;
 use {defmt_rtt as _, panic_probe as _};
 
@@ -13,11 +13,10 @@ fn main() -> ! {
     info!("Hello World!");
 
     let mut dac = DacCh1::new(p.DAC1, NoDma, p.PA4);
-    unwrap!(dac.set_trigger_enable(false));
 
     loop {
         for v in 0..=255 {
-            unwrap!(dac.set(Value::Bit8(to_sine_wave(v))));
+            dac.set(Value::Bit8(to_sine_wave(v)));
         }
     }
 }

examples/stm32l4/src/bin/dac_dma.rs

@@ -4,21 +4,15 @@
 
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::dac::{DacChannel, ValueArray};
+use embassy_stm32::dac::{DacCh1, DacCh2, ValueArray};
 use embassy_stm32::pac::timer::vals::{Mms, Opm};
-use embassy_stm32::peripherals::{TIM6, TIM7};
+use embassy_stm32::peripherals::{DAC1, DMA1_CH3, DMA1_CH4, TIM6, TIM7};
 use embassy_stm32::rcc::low_level::RccPeripheral;
 use embassy_stm32::time::Hertz;
 use embassy_stm32::timer::low_level::Basic16bitInstance;
 use micromath::F32Ext;
 use {defmt_rtt as _, panic_probe as _};
 
-pub type Dac1Type =
-    embassy_stm32::dac::DacCh1<'static, embassy_stm32::peripherals::DAC1, embassy_stm32::peripherals::DMA1_CH3>;
-
-pub type Dac2Type =
-    embassy_stm32::dac::DacCh2<'static, embassy_stm32::peripherals::DAC1, embassy_stm32::peripherals::DMA1_CH4>;
-
 #[embassy_executor::main]
 async fn main(spawner: Spawner) {
     let config = embassy_stm32::Config::default();
@@ -34,7 +28,7 @@ async fn main(spawner: Spawner) {
 }
 
 #[embassy_executor::task]
-async fn dac_task1(mut dac: Dac1Type) {
+async fn dac_task1(mut dac: DacCh1<'static, DAC1, DMA1_CH3>) {
     let data: &[u8; 256] = &calculate_array::<256>();
 
     info!("TIM6 frequency is {}", TIM6::frequency());
@@ -48,8 +42,9 @@ async fn dac_task1(mut dac: Dac1Type) {
         error!("Reload value {} below threshold!", reload);
     }
 
-    dac.select_trigger(embassy_stm32::dac::TriggerSel::Tim6).unwrap();
+    dac.set_trigger(embassy_stm32::dac::TriggerSel::Tim6);
-    dac.enable_channel().unwrap();
+    dac.set_triggering(true);
+    dac.enable();
 
     TIM6::enable_and_reset();
     TIM6::regs().arr().modify(|w| w.set_arr(reload as u16 - 1));
@@ -71,14 +66,12 @@ async fn dac_task1(mut dac: Dac1Type) {
     // Loop technically not necessary if DMA circular mode is enabled
     loop {
         info!("Loop DAC1");
-        if let Err(e) = dac.write(ValueArray::Bit8(data), true).await {
+        dac.write(ValueArray::Bit8(data), true).await;
-            error!("Could not write to dac: {}", e);
-        }
     }
 }
 
 #[embassy_executor::task]
-async fn dac_task2(mut dac: Dac2Type) {
+async fn dac_task2(mut dac: DacCh2<'static, DAC1, DMA1_CH4>) {
     let data: &[u8; 256] = &calculate_array::<256>();
 
     info!("TIM7 frequency is {}", TIM7::frequency());
@@ -98,7 +91,9 @@ async fn dac_task2(mut dac: Dac2Type) {
         w.set_cen(true);
     });
 
-    dac.select_trigger(embassy_stm32::dac::TriggerSel::Tim7).unwrap();
+    dac.set_trigger(embassy_stm32::dac::TriggerSel::Tim7);
+    dac.set_triggering(true);
+    dac.enable();
 
     debug!(
         "TIM7 Frequency {}, Target Frequency {}, Reload {}, Reload as u16 {}, Samples {}",
@@ -109,9 +104,7 @@ async fn dac_task2(mut dac: Dac2Type) {
         data.len()
     );
 
-    if let Err(e) = dac.write(ValueArray::Bit8(data), true).await {
+    dac.write(ValueArray::Bit8(data), true).await;
-        error!("Could not write to dac: {}", e);
-    }
 }
 
 fn to_sine_wave(v: u8) -> u8 {

tests/stm32/src/bin/dac.rs

@@ -10,7 +10,7 @@ use common::*;
 use defmt::assert;
 use embassy_executor::Spawner;
 use embassy_stm32::adc::Adc;
-use embassy_stm32::dac::{DacCh1, DacChannel, Value};
+use embassy_stm32::dac::{DacCh1, Value};
 use embassy_stm32::dma::NoDma;
 use embassy_time::{Delay, Timer};
 use {defmt_rtt as _, panic_probe as _};
@@ -26,9 +26,7 @@ async fn main(_spawner: Spawner) {
     #[cfg(any(feature = "stm32h755zi", feature = "stm32g071rb"))]
     let dac_peripheral = p.DAC1;
 
-    let mut dac: DacCh1<'_, _, NoDma> = DacCh1::new(dac_peripheral, NoDma, p.PA4);
+    let mut dac = DacCh1::new(dac_peripheral, NoDma, p.PA4);
-    unwrap!(dac.set_trigger_enable(false));
-
     let mut adc = Adc::new(p.ADC1, &mut Delay);
 
     #[cfg(feature = "stm32h755zi")]
@@ -36,7 +34,7 @@ async fn main(_spawner: Spawner) {
     #[cfg(any(feature = "stm32f429zi", feature = "stm32g071rb"))]
     let normalization_factor: i32 = 16;
 
-    unwrap!(dac.set(Value::Bit8(0)));
+    dac.set(Value::Bit8(0));
     // Now wait a little to obtain a stable value
     Timer::after_millis(30).await;
     let offset = adc.read(&mut unsafe { embassy_stm32::Peripherals::steal() }.PA4);
@@ -44,7 +42,7 @@ async fn main(_spawner: Spawner) {
     for v in 0..=255 {
         // First set the DAC output value
         let dac_output_val = to_sine_wave(v);
-        unwrap!(dac.set(Value::Bit8(dac_output_val)));
+        dac.set(Value::Bit8(dac_output_val));
 
         // Now wait a little to obtain a stable value
         Timer::after_millis(30).await;