Merge pull request #4646 from Iooon/mspm0-adc

MSPM0: add adc implementation

6 files changed, 612 insertions, 0 deletions

diff --git a/embassy-mspm0/CHANGELOG.md b/embassy-mspm0/CHANGELOG.md
index c7da4eb33..b846f21b1 100644
--- a/embassy-mspm0/CHANGELOG.md
+++ b/embassy-mspm0/CHANGELOG.md
@@ -12,3 +12,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - fix gpio interrupt not being set for mspm0l110x
 - feat: Add window watchdog implementation based on WWDT0, WWDT1 peripherals (#4574)
 - feat: Add MSPM0C1105/C1106 support
+- feat: Add adc implementation (#4646)
diff --git a/embassy-mspm0/build.rs b/embassy-mspm0/build.rs
index e8364e31a..d294bc422 100644
--- a/embassy-mspm0/build.rs
+++ b/embassy-mspm0/build.rs
@@ -68,6 +68,7 @@ fn generate_code() {
     g.extend(generate_pin_trait_impls());
     g.extend(generate_groups());
     g.extend(generate_dma_channel_count());
+    g.extend(generate_adc_constants(&mut cfgs));
 
     let out_dir = &PathBuf::from(env::var_os("OUT_DIR").unwrap());
     let out_file = out_dir.join("_generated.rs").to_string_lossy().to_string();
@@ -220,6 +221,22 @@ fn generate_dma_channel_count() -> TokenStream {
     quote! { pub const DMA_CHANNELS: usize = #count; }
 }
 
+fn generate_adc_constants(cfgs: &mut CfgSet) -> TokenStream {
+    let vrsel = METADATA.adc_vrsel;
+    let memctl = METADATA.adc_memctl;
+
+    cfgs.declare("adc_neg_vref");
+    match vrsel {
+        3 => (),
+        5 => cfgs.enable("adc_neg_vref"),
+        _ => panic!("Unsupported ADC VRSEL value: {vrsel}"),
+    }
+    quote! {
+        pub const ADC_VRSEL: u8 = #vrsel;
+        pub const ADC_MEMCTL: u8 = #memctl;
+    }
+}
+
 #[derive(Debug, Clone)]
 struct Singleton {
     name: String,
@@ -561,6 +578,7 @@ fn generate_peripheral_instances() -> TokenStream {
             "uart" => Some(quote! { impl_uart_instance!(#peri); }),
             "i2c" => Some(quote! { impl_i2c_instance!(#peri, #fifo_size); }),
             "wwdt" => Some(quote! { impl_wwdt_instance!(#peri); }),
+            "adc" => Some(quote! { impl_adc_instance!(#peri); }),
             _ => None,
         };
 
@@ -609,6 +627,10 @@ fn generate_pin_trait_impls() -> TokenStream {
                 ("uart", "RTS") => Some(quote! { impl_uart_rts_pin!(#peri, #pin_name, #pf); }),
                 ("i2c", "SDA") => Some(quote! { impl_i2c_sda_pin!(#peri, #pin_name, #pf); }),
                 ("i2c", "SCL") => Some(quote! { impl_i2c_scl_pin!(#peri, #pin_name, #pf); }),
+                ("adc", s) => {
+                    let signal = s.parse::<u8>().unwrap();
+                    Some(quote! { impl_adc_pin!(#peri, #pin_name, #signal); })
+                }
 
                 _ => None,
             };
diff --git a/embassy-mspm0/src/adc.rs b/embassy-mspm0/src/adc.rs
new file mode 100644
index 000000000..5b93e9a6e
--- /dev/null
+++ b/embassy-mspm0/src/adc.rs
@@ -0,0 +1,510 @@
+#![macro_use]
+
+use core::future::poll_fn;
+use core::marker::PhantomData;
+use core::task::Poll;
+
+use embassy_hal_internal::{impl_peripheral, PeripheralType};
+use embassy_sync::waitqueue::AtomicWaker;
+
+use crate::interrupt::{Interrupt, InterruptExt};
+use crate::mode::{Async, Blocking, Mode};
+use crate::pac::adc::{vals, Adc as Regs};
+use crate::{interrupt, Peri};
+
+/// 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() {
+        // Mis is cleared upon reading iidx
+        let iidx = T::info().regs.cpu_int(0).iidx().read().stat();
+        // TODO: Running in sequence mode, we get an interrupt per finished result. It would be
+        // nice to wake up only after all results are finished.
+        if vals::CpuIntIidxStat::MEMRESIFG0 <= iidx && iidx <= vals::CpuIntIidxStat::MEMRESIFG23 {
+            T::state().waker.wake();
+        }
+    }
+}
+
+// Constants from the metapac crate
+const ADC_VRSEL: u8 = crate::_generated::ADC_VRSEL;
+const ADC_MEMCTL: u8 = crate::_generated::ADC_MEMCTL;
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+/// Conversion resolution of the ADC results.
+pub enum Resolution {
+    /// 12-bits resolution
+    BIT12,
+
+    /// 10-bits resolution
+    BIT10,
+
+    /// 8-bits resolution
+    BIT8,
+}
+
+impl Resolution {
+    /// Number of bits of the resolution.
+    pub fn bits(&self) -> u8 {
+        match self {
+            Resolution::BIT12 => 12,
+            Resolution::BIT10 => 10,
+            Resolution::BIT8 => 8,
+        }
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Eq, Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+/// Reference voltage (Vref) selection for the ADC channels.
+pub enum Vrsel {
+    /// VDDA reference
+    VddaVssa = 0,
+
+    /// External reference from pin
+    ExtrefVrefm = 1,
+
+    /// Internal reference
+    IntrefVssa = 2,
+
+    /// VDDA and VREFM connected to VREF+ and VREF- of ADC
+    #[cfg(adc_neg_vref)]
+    VddaVrefm = 3,
+
+    /// INTREF and VREFM connected to VREF+ and VREF- of ADC
+    #[cfg(adc_neg_vref)]
+    IntrefVrefm = 4,
+}
+
+/// ADC configuration.
+#[derive(Copy, Clone)]
+#[non_exhaustive]
+pub struct Config {
+    /// Resolution of the ADC conversion. The number of bits used to represent an ADC measurement.
+    pub resolution: Resolution,
+    /// ADC voltage reference selection.
+    ///
+    /// This value is used when reading a single channel. When reading a sequence
+    /// the vr_select is provided per channel.
+    pub vr_select: Vrsel,
+    /// The sample time in number of ADC sample clock cycles.
+    pub sample_time: u16,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            resolution: Resolution::BIT12,
+            vr_select: Vrsel::VddaVssa,
+            sample_time: 50,
+        }
+    }
+}
+
+/// ADC (Analog to Digial Converter) Driver.
+pub struct Adc<'d, T: Instance, M: Mode> {
+    #[allow(unused)]
+    adc: crate::Peri<'d, T>,
+    info: &'static Info,
+    state: &'static State,
+    config: Config,
+    _phantom: PhantomData<M>,
+}
+
+impl<'d, T: Instance> Adc<'d, T, Blocking> {
+    /// A new blocking ADC driver instance.
+    pub fn new_blocking(peri: Peri<'d, T>, config: Config) -> Self {
+        let mut this = Self {
+            adc: peri,
+            info: T::info(),
+            state: T::state(),
+            config,
+            _phantom: PhantomData,
+        };
+        this.setup();
+        this
+    }
+}
+
+impl<'d, T: Instance> Adc<'d, T, Async> {
+    /// A new asynchronous ADC driver instance.
+    pub fn new_async(
+        peri: Peri<'d, T>,
+        config: Config,
+        _irqs: impl interrupt::typelevel::Binding<T::Interrupt, InterruptHandler<T>> + 'd,
+    ) -> Self {
+        let mut this = Self {
+            adc: peri,
+            info: T::info(),
+            state: T::state(),
+            config,
+            _phantom: PhantomData,
+        };
+        this.setup();
+        unsafe {
+            this.info.interrupt.enable();
+        }
+        this
+    }
+}
+
+impl<'d, T: Instance, M: Mode> Adc<'d, T, M> {
+    const SINGLE_CHANNEL: u8 = 0;
+
+    fn setup(&mut self) {
+        let config = &self.config;
+        assert!(
+            (config.vr_select as u8) < ADC_VRSEL,
+            "Reference voltage selection out of bounds"
+        );
+        // Reset adc
+        self.info.regs.gprcm(0).rstctl().write(|reg| {
+            reg.set_resetstkyclr(true);
+            reg.set_resetassert(true);
+            reg.set_key(vals::ResetKey::KEY);
+        });
+
+        // Power up adc
+        self.info.regs.gprcm(0).pwren().modify(|reg| {
+            reg.set_enable(true);
+            reg.set_key(vals::PwrenKey::KEY);
+        });
+
+        // Wait for cycles similar to TI power setup
+        cortex_m::asm::delay(16);
+
+        // Set clock config
+        self.info.regs.gprcm(0).clkcfg().modify(|reg| {
+            reg.set_key(vals::ClkcfgKey::KEY);
+            reg.set_sampclk(vals::Sampclk::SYSOSC);
+        });
+        self.info.regs.ctl0().modify(|reg| {
+            reg.set_sclkdiv(vals::Sclkdiv::DIV_BY_4);
+        });
+        self.info.regs.clkfreq().modify(|reg| {
+            reg.set_frange(vals::Frange::RANGE24TO32);
+        });
+
+        // Init single conversion with software trigger and auto sampling
+        //
+        // We use sequence to support sequence operation in the future, but only set up a single
+        // channel
+        self.info.regs.ctl1().modify(|reg| {
+            reg.set_conseq(vals::Conseq::SEQUENCE);
+            reg.set_sampmode(vals::Sampmode::AUTO);
+            reg.set_trigsrc(vals::Trigsrc::SOFTWARE);
+        });
+        let res = match config.resolution {
+            Resolution::BIT12 => vals::Res::BIT_12,
+            Resolution::BIT10 => vals::Res::BIT_10,
+            Resolution::BIT8 => vals::Res::BIT_8,
+        };
+        self.info.regs.ctl2().modify(|reg| {
+            // Startadd detemines the channel used in single mode.
+            reg.set_startadd(Self::SINGLE_CHANNEL);
+            reg.set_endadd(Self::SINGLE_CHANNEL);
+            reg.set_res(res);
+            reg.set_df(false);
+        });
+
+        // Set the sample time used by all channels for now
+        self.info.regs.scomp0().modify(|reg| {
+            reg.set_val(config.sample_time);
+        });
+    }
+
+    fn setup_blocking_channel(&mut self, channel: &Peri<'d, impl AdcChannel<T>>) {
+        channel.setup();
+
+        // CTL0.ENC must be 0 to write the MEMCTL register
+        while self.info.regs.ctl0().read().enc() {
+            // Wait until the ADC is not in conversion mode
+        }
+
+        // Conversion mem config
+        let vrsel = vals::Vrsel::from_bits(self.config.vr_select as u8);
+        self.info.regs.memctl(Self::SINGLE_CHANNEL as usize).modify(|reg| {
+            reg.set_chansel(channel.channel());
+            reg.set_vrsel(vrsel);
+            reg.set_stime(vals::Stime::SEL_SCOMP0);
+            reg.set_avgen(false);
+            reg.set_bcsen(false);
+            reg.set_trig(vals::Trig::AUTO_NEXT);
+            reg.set_wincomp(false);
+        });
+        self.info.regs.ctl2().modify(|reg| {
+            // Set end address to the number of used channels
+            reg.set_endadd(Self::SINGLE_CHANNEL);
+        });
+    }
+
+    fn enable_conversion(&mut self) {
+        // Enable conversion
+        self.info.regs.ctl0().modify(|reg| {
+            reg.set_enc(true);
+        });
+    }
+
+    fn start_conversion(&mut self) {
+        // Start conversion
+        self.info.regs.ctl1().modify(|reg| {
+            reg.set_sc(vals::Sc::START);
+        });
+    }
+
+    fn conversion_result(&mut self, channel_id: usize) -> u16 {
+        // Read result
+        self.info.regs.memres(channel_id).read().data()
+    }
+
+    /// Read one ADC channel in blocking mode using the config provided at initialization.
+    pub fn blocking_read(&mut self, channel: &Peri<'d, impl AdcChannel<T>>) -> u16 {
+        self.setup_blocking_channel(channel);
+        self.enable_conversion();
+        self.start_conversion();
+
+        while self.info.regs.ctl0().read().enc() {}
+
+        self.conversion_result(Self::SINGLE_CHANNEL as usize)
+    }
+}
+
+impl<'d, T: Instance> Adc<'d, T, Async> {
+    /// Maximum length allowed for [`Self::read_sequence`].
+    pub const MAX_SEQUENCE_LEN: usize = ADC_MEMCTL as usize;
+
+    async fn wait_for_conversion(&self) {
+        let info = self.info;
+        let state = self.state;
+        poll_fn(move |cx| {
+            state.waker.register(cx.waker());
+
+            if !info.regs.ctl0().read().enc() {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            }
+        })
+        .await;
+    }
+
+    fn setup_async_channel(&self, id: usize, channel: &Peri<'d, impl AdcChannel<T>>, vrsel: Vrsel) {
+        let vrsel = vals::Vrsel::from_bits(vrsel as u8);
+        // Conversion mem config
+        self.info.regs.memctl(id).modify(|reg| {
+            reg.set_chansel(channel.channel());
+            reg.set_vrsel(vrsel);
+            reg.set_stime(vals::Stime::SEL_SCOMP0);
+            reg.set_avgen(false);
+            reg.set_bcsen(false);
+            reg.set_trig(vals::Trig::AUTO_NEXT);
+            reg.set_wincomp(false);
+        });
+
+        // Clear interrupt status
+        self.info.regs.cpu_int(0).iclr().write(|reg| {
+            reg.set_memresifg(id, true);
+        });
+        // Enable interrupt
+        self.info.regs.cpu_int(0).imask().modify(|reg| {
+            reg.set_memresifg(id, true);
+        });
+    }
+
+    /// Read one ADC channel asynchronously using the config provided at initialization.
+    pub async fn read_channel(&mut self, channel: &Peri<'d, impl AdcChannel<T>>) -> u16 {
+        channel.setup();
+
+        // CTL0.ENC must be 0 to write the MEMCTL register
+        self.wait_for_conversion().await;
+
+        self.info.regs.ctl2().modify(|reg| {
+            // Set end address to the number of used channels
+            reg.set_endadd(Self::SINGLE_CHANNEL);
+        });
+
+        self.setup_async_channel(Self::SINGLE_CHANNEL as usize, channel, self.config.vr_select);
+
+        self.enable_conversion();
+        self.start_conversion();
+        self.wait_for_conversion().await;
+
+        self.conversion_result(Self::SINGLE_CHANNEL as usize)
+    }
+
+    /// Read one or multiple ADC channels using the Vrsel provided per channel.
+    ///
+    /// `sequence` iterator and `readings` must have the same length.
+    ///
+    /// Example
+    /// ```rust,ignore
+    /// use embassy_mspm0::adc::{Adc, AdcChannel, Vrsel};
+    ///
+    /// let mut adc = Adc::new_async(p.ADC0, adc_config, Irqs);
+    /// let sequence = [(&p.PA22.into(), Vrsel::VddaVssa), (&p.PA20.into(), Vrsel::VddaVssa)];
+    /// let mut readings = [0u16; 2];
+    ///
+    /// adc.read_sequence(sequence.into_iter(), &mut readings).await;
+    /// defmt::info!("Measurements: {}", readings);
+    /// ```
+    pub async fn read_sequence<'a>(
+        &mut self,
+        sequence: impl ExactSizeIterator<Item = (&'a Peri<'d, AnyAdcChannel<T>>, Vrsel)>,
+        readings: &mut [u16],
+    ) where
+        'd: 'a,
+    {
+        assert!(sequence.len() != 0, "Asynchronous read sequence cannot be empty");
+        assert!(
+            sequence.len() == readings.len(),
+            "Sequence length must be equal to readings length"
+        );
+        assert!(
+            sequence.len() <= Self::MAX_SEQUENCE_LEN,
+            "Asynchronous read sequence cannot be more than {} in length",
+            Self::MAX_SEQUENCE_LEN
+        );
+
+        // CTL0.ENC must be 0 to write the MEMCTL register
+        self.wait_for_conversion().await;
+
+        self.info.regs.ctl2().modify(|reg| {
+            // Set end address to the number of used channels
+            reg.set_endadd((sequence.len() - 1) as u8);
+        });
+
+        for (i, (channel, vrsel)) in sequence.enumerate() {
+            self.setup_async_channel(i, channel, vrsel);
+        }
+        self.enable_conversion();
+        self.start_conversion();
+        self.wait_for_conversion().await;
+
+        for (i, r) in readings.iter_mut().enumerate() {
+            *r = self.conversion_result(i);
+        }
+    }
+}
+
+/// Peripheral instance trait.
+#[allow(private_bounds)]
+pub trait Instance: PeripheralType + SealedInstance {
+    type Interrupt: crate::interrupt::typelevel::Interrupt;
+}
+
+/// Peripheral state.
+pub(crate) struct State {
+    waker: AtomicWaker,
+}
+
+impl State {
+    pub const fn new() -> Self {
+        Self {
+            waker: AtomicWaker::new(),
+        }
+    }
+}
+
+/// Peripheral information.
+pub(crate) struct Info {
+    pub(crate) regs: Regs,
+    pub(crate) interrupt: Interrupt,
+}
+
+/// Peripheral instance trait.
+pub(crate) trait SealedInstance {
+    fn info() -> &'static Info;
+    fn state() -> &'static State;
+}
+
+macro_rules! impl_adc_instance {
+    ($instance: ident) => {
+        impl crate::adc::SealedInstance for crate::peripherals::$instance {
+            fn info() -> &'static crate::adc::Info {
+                use crate::adc::Info;
+                use crate::interrupt::typelevel::Interrupt;
+
+                static INFO: Info = Info {
+                    regs: crate::pac::$instance,
+                    interrupt: crate::interrupt::typelevel::$instance::IRQ,
+                };
+                &INFO
+            }
+
+            fn state() -> &'static crate::adc::State {
+                use crate::adc::State;
+
+                static STATE: State = State::new();
+                &STATE
+            }
+        }
+
+        impl crate::adc::Instance for crate::peripherals::$instance {
+            type Interrupt = crate::interrupt::typelevel::$instance;
+        }
+    };
+}
+
+/// A type-erased channel for a given ADC instance.
+///
+/// This is useful in scenarios where you need the ADC channels to have the same type, such as
+/// storing them in an array.
+pub struct AnyAdcChannel<T> {
+    pub(crate) channel: u8,
+    pub(crate) _phantom: PhantomData<T>,
+}
+
+impl_peripheral!(AnyAdcChannel<T: Instance>);
+impl<T: Instance> AdcChannel<T> for AnyAdcChannel<T> {}
+impl<T: Instance> SealedAdcChannel<T> for AnyAdcChannel<T> {
+    fn channel(&self) -> u8 {
+        self.channel
+    }
+}
+
+impl<T> AnyAdcChannel<T> {
+    #[allow(unused)]
+    pub(crate) fn get_hw_channel(&self) -> u8 {
+        self.channel
+    }
+}
+
+/// ADC channel.
+#[allow(private_bounds)]
+pub trait AdcChannel<T>: PeripheralType + Into<AnyAdcChannel<T>> + SealedAdcChannel<T> + Sized {}
+
+pub(crate) trait SealedAdcChannel<T> {
+    fn setup(&self) {}
+
+    fn channel(&self) -> u8;
+}
+
+macro_rules! impl_adc_pin {
+    ($inst: ident, $pin: ident, $ch: expr) => {
+        impl crate::adc::AdcChannel<peripherals::$inst> for crate::peripherals::$pin {}
+        impl crate::adc::SealedAdcChannel<peripherals::$inst> for crate::peripherals::$pin {
+            fn setup(&self) {
+                crate::gpio::SealedPin::set_as_analog(self);
+            }
+
+            fn channel(&self) -> u8 {
+                $ch
+            }
+        }
+
+        impl From<crate::peripherals::$pin> for crate::adc::AnyAdcChannel<peripherals::$inst> {
+            fn from(val: crate::peripherals::$pin) -> Self {
+                crate::adc::SealedAdcChannel::<peripherals::$inst>::setup(&val);
+
+                Self {
+                    channel: crate::adc::SealedAdcChannel::<peripherals::$inst>::channel(&val),
+                    _phantom: core::marker::PhantomData,
+                }
+            }
+        }
+    };
+}
diff --git a/embassy-mspm0/src/lib.rs b/embassy-mspm0/src/lib.rs
index 0cb19a379..13f0ce662 100644
--- a/embassy-mspm0/src/lib.rs
+++ b/embassy-mspm0/src/lib.rs
@@ -13,6 +13,7 @@ pub(crate) mod fmt;
 // This must be declared early as well for
 mod macros;
 
+pub mod adc;
 pub mod dma;
 pub mod gpio;
 pub mod i2c;
diff --git a/examples/mspm0g3507/src/bin/adc.rs b/examples/mspm0g3507/src/bin/adc.rs
new file mode 100644
index 000000000..ceccc7c02
--- /dev/null
+++ b/examples/mspm0g3507/src/bin/adc.rs
@@ -0,0 +1,39 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_mspm0::adc::{self, Adc, Vrsel};
+use embassy_mspm0::{bind_interrupts, peripherals, Config};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_halt as _};
+
+bind_interrupts!(struct Irqs {
+    ADC0 => adc::InterruptHandler<peripherals::ADC0>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    info!("Hello world!");
+    let p = embassy_mspm0::init(Config::default());
+
+    // Configure adc with sequence 0 to 1
+    let mut adc = Adc::new_async(p.ADC0, Default::default(), Irqs);
+    let sequence = [(&p.PA22.into(), Vrsel::VddaVssa), (&p.PB20.into(), Vrsel::VddaVssa)];
+    let mut readings = [0u16; 2];
+
+    loop {
+        let r = adc.read_channel(&p.PA27).await;
+        info!("Raw adc PA27: {}", r);
+        // With a voltage range of 0-3.3V and a resolution of 12 bits, the raw value can be
+        // approximated to voltage (~0.0008 per step).
+        let mut x = r as u32;
+        x = x * 8;
+        info!("Adc voltage PA27: {},{:#04}", x / 10_000, x % 10_000);
+        // Read a sequence of channels
+        adc.read_sequence(sequence.into_iter(), &mut readings).await;
+        info!("Raw adc sequence: {}", readings);
+
+        Timer::after_millis(400).await;
+    }
+}
diff --git a/examples/mspm0l1306/src/bin/adc.rs b/examples/mspm0l1306/src/bin/adc.rs
new file mode 100644
index 000000000..2806b98cc
--- /dev/null
+++ b/examples/mspm0l1306/src/bin/adc.rs
@@ -0,0 +1,39 @@
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_mspm0::adc::{self, Adc, Vrsel};
+use embassy_mspm0::{bind_interrupts, peripherals, Config};
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_halt as _};
+
+bind_interrupts!(struct Irqs {
+    ADC0 => adc::InterruptHandler<peripherals::ADC0>;
+});
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) -> ! {
+    info!("Hello world!");
+    let p = embassy_mspm0::init(Config::default());
+
+    // Configure adc with sequence 0 to 1
+    let mut adc = Adc::new_async(p.ADC0, Default::default(), Irqs);
+    let sequence = [(&p.PA22.into(), Vrsel::VddaVssa), (&p.PA20.into(), Vrsel::VddaVssa)];
+    let mut readings = [0u16; 2];
+
+    loop {
+        let r = adc.read_channel(&p.PA27).await;
+        info!("Raw adc PA27: {}", r);
+        // With a voltage range of 0-3.3V and a resolution of 12 bits, the raw value can be
+        // approximated to voltage (~0.0008 per step).
+        let mut x = r as u32;
+        x = x * 8;
+        info!("Adc voltage PA27: {},{:#04}", x / 10_000, x % 10_000);
+        // Read a sequence of channels
+        adc.read_sequence(sequence.into_iter(), &mut readings).await;
+        info!("Raw adc sequence: {}", readings);
+
+        Timer::after_millis(400).await;
+    }
+}