377 lines
11 KiB
Rust
377 lines
11 KiB
Rust
//! ADC driver.
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use core::future::poll_fn;
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use core::marker::PhantomData;
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use core::mem;
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use core::sync::atomic::{compiler_fence, Ordering};
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use core::task::Poll;
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use embassy_hal_internal::{into_ref, PeripheralRef};
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use embassy_sync::waitqueue::AtomicWaker;
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use crate::gpio::sealed::Pin as GpioPin;
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use crate::gpio::{self, AnyPin, Pull};
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use crate::interrupt::typelevel::Binding;
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use crate::interrupt::InterruptExt;
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use crate::peripherals::{ADC, ADC_TEMP_SENSOR};
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use crate::{dma, interrupt, pac, peripherals, Peripheral, RegExt};
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static WAKER: AtomicWaker = AtomicWaker::new();
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/// ADC config.
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#[non_exhaustive]
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pub struct Config {}
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impl Default for Config {
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fn default() -> Self {
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Self {}
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}
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}
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enum Source<'p> {
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Pin(PeripheralRef<'p, AnyPin>),
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TempSensor(PeripheralRef<'p, ADC_TEMP_SENSOR>),
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}
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/// ADC channel.
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pub struct Channel<'p>(Source<'p>);
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impl<'p> Channel<'p> {
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/// Create a new ADC channel from pin with the provided [Pull] configuration.
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pub fn new_pin(pin: impl Peripheral<P = impl AdcPin + 'p> + 'p, pull: Pull) -> Self {
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into_ref!(pin);
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pin.pad_ctrl().modify(|w| {
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// manual says:
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//
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// > When using an ADC input shared with a GPIO pin, the pin’s
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// > digital functions must be disabled by setting IE low and OD
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// > high in the pin’s pad control register
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w.set_ie(false);
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w.set_od(true);
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w.set_pue(pull == Pull::Up);
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w.set_pde(pull == Pull::Down);
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});
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Self(Source::Pin(pin.map_into()))
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}
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/// Create a new ADC channel for the internal temperature sensor.
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pub fn new_temp_sensor(s: impl Peripheral<P = ADC_TEMP_SENSOR> + 'p) -> Self {
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let r = pac::ADC;
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r.cs().write_set(|w| w.set_ts_en(true));
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Self(Source::TempSensor(s.into_ref()))
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}
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fn channel(&self) -> u8 {
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match &self.0 {
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// this requires adc pins to be sequential and matching the adc channels,
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// which is the case for rp2040
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Source::Pin(p) => p._pin() - 26,
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Source::TempSensor(_) => 4,
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}
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}
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}
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impl<'p> Drop for Source<'p> {
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fn drop(&mut self) {
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match self {
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Source::Pin(p) => {
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p.pad_ctrl().modify(|w| {
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w.set_ie(true);
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w.set_od(false);
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w.set_pue(false);
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w.set_pde(true);
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});
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}
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Source::TempSensor(_) => {
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pac::ADC.cs().write_clear(|w| w.set_ts_en(true));
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}
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}
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}
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}
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/// ADC sample.
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#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Default)]
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#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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#[repr(transparent)]
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pub struct Sample(u16);
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impl Sample {
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/// Sample is valid.
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pub fn good(&self) -> bool {
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self.0 < 0x8000
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}
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/// Sample value.
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pub fn value(&self) -> u16 {
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self.0 & !0x8000
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}
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}
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/// ADC error.
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#[derive(Debug, Eq, PartialEq, Copy, Clone)]
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#[cfg_attr(feature = "defmt", derive(defmt::Format))]
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pub enum Error {
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/// Error converting value.
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ConversionFailed,
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}
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/// ADC mode.
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pub trait Mode {}
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/// ADC async mode.
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pub struct Async;
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impl Mode for Async {}
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/// ADC blocking mode.
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pub struct Blocking;
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impl Mode for Blocking {}
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/// ADC driver.
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pub struct Adc<'d, M: Mode> {
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phantom: PhantomData<(&'d ADC, M)>,
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}
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impl<'d, M: Mode> Drop for Adc<'d, M> {
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fn drop(&mut self) {
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let r = Self::regs();
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// disable ADC. leaving it enabled comes with a ~150µA static
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// current draw. the temperature sensor has already been disabled
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// by the temperature-reading methods, so we don't need to touch that.
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r.cs().write(|w| w.set_en(false));
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}
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}
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impl<'d, M: Mode> Adc<'d, M> {
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#[inline]
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fn regs() -> pac::adc::Adc {
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pac::ADC
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}
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#[inline]
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fn reset() -> pac::resets::regs::Peripherals {
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let mut ret = pac::resets::regs::Peripherals::default();
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ret.set_adc(true);
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ret
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}
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fn setup() {
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let reset = Self::reset();
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crate::reset::reset(reset);
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crate::reset::unreset_wait(reset);
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let r = Self::regs();
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// Enable ADC
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r.cs().write(|w| w.set_en(true));
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// Wait for ADC ready
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while !r.cs().read().ready() {}
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}
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/// Sample a value from a channel in blocking mode.
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pub fn blocking_read(&mut self, ch: &mut Channel) -> Result<u16, Error> {
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let r = Self::regs();
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r.cs().modify(|w| {
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w.set_ainsel(ch.channel());
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w.set_start_once(true);
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w.set_err(true);
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});
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while !r.cs().read().ready() {}
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match r.cs().read().err() {
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true => Err(Error::ConversionFailed),
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false => Ok(r.result().read().result().into()),
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}
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}
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}
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impl<'d> Adc<'d, Async> {
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/// Create ADC driver in async mode.
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pub fn new(
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_inner: impl Peripheral<P = ADC> + 'd,
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_irq: impl Binding<interrupt::typelevel::ADC_IRQ_FIFO, InterruptHandler>,
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_config: Config,
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) -> Self {
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Self::setup();
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// Setup IRQ
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interrupt::ADC_IRQ_FIFO.unpend();
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unsafe { interrupt::ADC_IRQ_FIFO.enable() };
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Self { phantom: PhantomData }
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}
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async fn wait_for_ready() {
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let r = Self::regs();
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r.inte().write(|w| w.set_fifo(true));
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compiler_fence(Ordering::SeqCst);
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poll_fn(|cx| {
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WAKER.register(cx.waker());
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if r.cs().read().ready() {
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return Poll::Ready(());
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}
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Poll::Pending
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})
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.await;
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}
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/// Sample a value from a channel until completed.
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pub async fn read(&mut self, ch: &mut Channel<'_>) -> Result<u16, Error> {
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let r = Self::regs();
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r.cs().modify(|w| {
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w.set_ainsel(ch.channel());
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w.set_start_once(true);
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w.set_err(true);
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});
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Self::wait_for_ready().await;
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match r.cs().read().err() {
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true => Err(Error::ConversionFailed),
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false => Ok(r.result().read().result().into()),
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}
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}
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async fn read_many_inner<W: dma::Word>(
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&mut self,
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ch: &mut Channel<'_>,
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buf: &mut [W],
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fcs_err: bool,
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div: u16,
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dma: impl Peripheral<P = impl dma::Channel>,
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) -> Result<(), Error> {
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let r = Self::regs();
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// clear previous errors and set channel
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r.cs().modify(|w| {
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w.set_ainsel(ch.channel());
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w.set_err_sticky(true); // clear previous errors
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w.set_start_many(false);
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});
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// wait for previous conversions and drain fifo. an earlier batch read may have
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// been cancelled, leaving the adc running.
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while !r.cs().read().ready() {}
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while !r.fcs().read().empty() {
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r.fifo().read();
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}
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// set up fifo for dma
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r.fcs().write(|w| {
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w.set_thresh(1);
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w.set_dreq_en(true);
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w.set_shift(mem::size_of::<W>() == 1);
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w.set_en(true);
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w.set_err(fcs_err);
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});
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// reset dma config on drop, regardless of whether it was a future being cancelled
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// or the method returning normally.
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struct ResetDmaConfig;
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impl Drop for ResetDmaConfig {
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fn drop(&mut self) {
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pac::ADC.cs().write_clear(|w| w.set_start_many(true));
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while !pac::ADC.cs().read().ready() {}
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pac::ADC.fcs().write_clear(|w| {
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w.set_dreq_en(true);
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w.set_shift(true);
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w.set_en(true);
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});
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}
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}
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let auto_reset = ResetDmaConfig;
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let dma = unsafe { dma::read(dma, r.fifo().as_ptr() as *const W, buf as *mut [W], 36) };
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// start conversions and wait for dma to finish. we can't report errors early
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// because there's no interrupt to signal them, and inspecting every element
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// of the fifo is too costly to do here.
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r.div().write_set(|w| w.set_int(div));
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r.cs().write_set(|w| w.set_start_many(true));
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dma.await;
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mem::drop(auto_reset);
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// we can't report errors before the conversions have ended since no interrupt
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// exists to report them early, and since they're exceedingly rare we probably don't
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// want to anyway.
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match r.cs().read().err_sticky() {
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false => Ok(()),
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true => Err(Error::ConversionFailed),
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}
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}
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/// Sample multiple values from a channel using DMA.
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#[inline]
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pub async fn read_many<S: AdcSample>(
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&mut self,
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ch: &mut Channel<'_>,
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buf: &mut [S],
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div: u16,
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dma: impl Peripheral<P = impl dma::Channel>,
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) -> Result<(), Error> {
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self.read_many_inner(ch, buf, false, div, dma).await
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}
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/// Sample multiple values from a channel using DMA with errors inlined in samples.
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#[inline]
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pub async fn read_many_raw(
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&mut self,
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ch: &mut Channel<'_>,
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buf: &mut [Sample],
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div: u16,
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dma: impl Peripheral<P = impl dma::Channel>,
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) {
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// errors are reported in individual samples
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let _ = self
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.read_many_inner(ch, unsafe { mem::transmute::<_, &mut [u16]>(buf) }, true, div, dma)
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.await;
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}
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}
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impl<'d> Adc<'d, Blocking> {
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/// Create ADC driver in blocking mode.
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pub fn new_blocking(_inner: impl Peripheral<P = ADC> + 'd, _config: Config) -> Self {
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Self::setup();
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Self { phantom: PhantomData }
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}
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}
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/// Interrupt handler.
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pub struct InterruptHandler {
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_empty: (),
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}
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impl interrupt::typelevel::Handler<interrupt::typelevel::ADC_IRQ_FIFO> for InterruptHandler {
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unsafe fn on_interrupt() {
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let r = Adc::<Async>::regs();
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r.inte().write(|w| w.set_fifo(false));
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WAKER.wake();
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}
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}
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mod sealed {
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pub trait AdcSample: crate::dma::Word {}
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pub trait AdcChannel {}
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}
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/// ADC sample.
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pub trait AdcSample: sealed::AdcSample {}
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impl sealed::AdcSample for u16 {}
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impl AdcSample for u16 {}
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impl sealed::AdcSample for u8 {}
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impl AdcSample for u8 {}
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/// ADC channel.
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pub trait AdcChannel: sealed::AdcChannel {}
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/// ADC pin.
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pub trait AdcPin: AdcChannel + gpio::Pin {}
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macro_rules! impl_pin {
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($pin:ident, $channel:expr) => {
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impl sealed::AdcChannel for peripherals::$pin {}
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impl AdcChannel for peripherals::$pin {}
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impl AdcPin for peripherals::$pin {}
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};
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}
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impl_pin!(PIN_26, 0);
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impl_pin!(PIN_27, 1);
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impl_pin!(PIN_28, 2);
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impl_pin!(PIN_29, 3);
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impl sealed::AdcChannel for peripherals::ADC_TEMP_SENSOR {}
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impl AdcChannel for peripherals::ADC_TEMP_SENSOR {}
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