nrf/ppi: implement and add example

embassy-nrf-examples/src/bin/ppi.rs

@@ -0,0 +1,112 @@
+#![no_std]
+#![no_main]
+#![feature(min_type_alias_impl_trait)]
+#![feature(impl_trait_in_bindings)]
+#![feature(type_alias_impl_trait)]
+#![allow(incomplete_features)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use core::future::pending;
+
+use example_common::*;
+
+use cortex_m_rt::entry;
+use defmt::panic;
+
+use embassy::executor::{task, Executor};
+use embassy::util::Forever;
+use embassy_nrf::gpio::{Input, Level, Output, OutputDrive, Pull};
+use embassy_nrf::gpiote::{self, InputChannel, InputChannelPolarity};
+use embassy_nrf::ppi::Ppi;
+use embassy_nrf::{interrupt, Peripherals};
+use futures::future;
+use gpiote::{OutputChannel, OutputChannelPolarity};
+
+#[task]
+async fn run() {
+    let p = Peripherals::take().unwrap();
+    let g = gpiote::initialize(p.GPIOTE, interrupt::take!(GPIOTE));
+
+    info!("Starting!");
+
+    let button1 = InputChannel::new(
+        g,
+        p.GPIOTE_CH0,
+        Input::new(p.P0_11, Pull::Up),
+        InputChannelPolarity::HiToLo,
+    );
+    let button2 = InputChannel::new(
+        g,
+        p.GPIOTE_CH1,
+        Input::new(p.P0_12, Pull::Up),
+        InputChannelPolarity::HiToLo,
+    );
+    let button3 = InputChannel::new(
+        g,
+        p.GPIOTE_CH2,
+        Input::new(p.P0_24, Pull::Up),
+        InputChannelPolarity::HiToLo,
+    );
+    let button4 = InputChannel::new(
+        g,
+        p.GPIOTE_CH3,
+        Input::new(p.P0_25, Pull::Up),
+        InputChannelPolarity::HiToLo,
+    );
+
+    let led1 = OutputChannel::new(
+        g,
+        p.GPIOTE_CH4,
+        Output::new(p.P0_13, Level::Low, OutputDrive::Standard),
+        OutputChannelPolarity::Toggle,
+    );
+
+    let led2 = OutputChannel::new(
+        g,
+        p.GPIOTE_CH5,
+        Output::new(p.P0_14, Level::Low, OutputDrive::Standard),
+        OutputChannelPolarity::Toggle,
+    );
+
+    let mut ppi = Ppi::new(p.PPI_CH0);
+    ppi.set_event(button1.event_in());
+    ppi.set_task(led1.task_out());
+    ppi.enable();
+
+    let mut ppi = Ppi::new(p.PPI_CH1);
+    ppi.set_event(button2.event_in());
+    ppi.set_task(led1.task_clr());
+    ppi.enable();
+
+    let mut ppi = Ppi::new(p.PPI_CH2);
+    ppi.set_event(button3.event_in());
+    ppi.set_task(led1.task_set());
+    ppi.enable();
+
+    let mut ppi = Ppi::new(p.PPI_CH3);
+    ppi.set_event(button4.event_in());
+    ppi.set_task(led1.task_out());
+    ppi.set_fork_task(led2.task_out());
+    ppi.enable();
+
+    info!("PPI setup!");
+    info!("Press button 1 to toggle LED 1");
+    info!("Press button 2 to turn on LED 1");
+    info!("Press button 3 to turn off LED 1");
+    info!("Press button 4 to toggle LEDs 1 and 2");
+    // Block forever so the above drivers don't get dropped
+    pending::<()>().await;
+}
+
+static EXECUTOR: Forever<Executor> = Forever::new();
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    let executor = EXECUTOR.put(Executor::new());
+    executor.run(|spawner| {
+        unwrap!(spawner.spawn(run()));
+    });
+}

embassy-nrf/src/gpiote.rs

@@ -7,19 +7,15 @@ use embassy::interrupt::InterruptExt;
 use embassy::traits::gpio::{WaitForHigh, WaitForLow};
 use embassy::util::AtomicWaker;
 use embassy_extras::impl_unborrow;
-use embedded_hal::digital::v2::{InputPin, OutputPin, StatefulOutputPin};
+use embedded_hal::digital::v2::{InputPin, StatefulOutputPin};
 use futures::future::poll_fn;
 
 use crate::gpio::sealed::Pin as _;
-use crate::gpio::{AnyPin, Input, Output, Pin as GpioPin, Port, Pull};
+use crate::gpio::{AnyPin, Input, Output, Pin as GpioPin, Port};
 use crate::pac;
-use crate::pac::generic::Reg;
+use crate::ppi::{Event, Task};
-use crate::pac::gpiote::_TASKS_OUT;
 use crate::{interrupt, peripherals};
 
-#[cfg(not(feature = "51"))]
-use crate::pac::gpiote::{_TASKS_CLR, _TASKS_SET};
-
 pub const CHANNEL_COUNT: usize = 8;
 
 #[cfg(any(feature = "52833", feature = "52840"))]
@@ -53,7 +49,7 @@ pub struct Initialized {
     _private: (),
 }
 
-pub fn initialize(gpiote: peripherals::GPIOTE, irq: interrupt::GPIOTE) -> Initialized {
+pub fn initialize(_gpiote: peripherals::GPIOTE, irq: interrupt::GPIOTE) -> Initialized {
     #[cfg(any(feature = "52833", feature = "52840"))]
     let ports = unsafe { &[&*pac::P0::ptr(), &*pac::P1::ptr()] };
     #[cfg(not(any(feature = "52833", feature = "52840")))]
@@ -122,6 +118,7 @@ impl Iterator for BitIter {
     }
 }
 
+/// GPIOTE channel driver in input mode
 pub struct InputChannel<'d, C: Channel, T: GpioPin> {
     ch: C,
     pin: Input<'d, T>,
@@ -185,6 +182,12 @@ impl<'d, C: Channel, T: GpioPin> InputChannel<'d, C, T> {
         })
         .await;
     }
+
+    /// Returns the IN event, for use with PPI.
+    pub fn event_in(&self) -> Event {
+        let g = unsafe { &*pac::GPIOTE::ptr() };
+        Event::from_reg(&g.events_in[self.ch.number()])
+    }
 }
 
 impl<'d, C: Channel, T: GpioPin> InputPin for InputChannel<'d, C, T> {
@@ -199,9 +202,10 @@ impl<'d, C: Channel, T: GpioPin> InputPin for InputChannel<'d, C, T> {
     }
 }
 
+/// GPIOTE channel driver in output mode
 pub struct OutputChannel<'d, C: Channel, T: GpioPin> {
     ch: C,
-    pin: Output<'d, T>,
+    _pin: Output<'d, T>,
 }
 
 impl<'d, C: Channel, T: GpioPin> Drop for OutputChannel<'d, C, T> {
@@ -242,7 +246,7 @@ impl<'d, C: Channel, T: GpioPin> OutputChannel<'d, C, T> {
             unsafe { w.psel().bits(pin.pin.pin()) }
         });
 
-        OutputChannel { ch, pin }
+        OutputChannel { ch, _pin: pin }
     }
 
     /// Triggers `task out` (as configured with task_out_polarity, defaults to Toggle).
@@ -265,28 +269,28 @@ impl<'d, C: Channel, T: GpioPin> OutputChannel<'d, C, T> {
         g.tasks_clr[self.ch.number()].write(|w| unsafe { w.bits(1) });
     }
 
-    /// Returns reference to task_out endpoint for PPI.
+    /// Returns the OUT task, for use with PPI.
-    pub fn task_out(&self) -> &Reg<u32, _TASKS_OUT> {
+    pub fn task_out(&self) -> Task {
         let g = unsafe { &*pac::GPIOTE::ptr() };
-        &g.tasks_out[self.ch.number()]
+        Task::from_reg(&g.tasks_out[self.ch.number()])
     }
 
-    /// Returns reference to task_clr endpoint for PPI.
+    /// Returns the CLR task, for use with PPI.
     #[cfg(not(feature = "51"))]
-    pub fn task_clr(&self) -> &Reg<u32, _TASKS_CLR> {
+    pub fn task_clr(&self) -> Task {
         let g = unsafe { &*pac::GPIOTE::ptr() };
-        &g.tasks_clr[self.ch.number()]
+        Task::from_reg(&g.tasks_clr[self.ch.number()])
     }
 
-    /// Returns reference to task_set endpoint for PPI.
+    /// Returns the SET task, for use with PPI.
     #[cfg(not(feature = "51"))]
-    pub fn task_set(&self) -> &Reg<u32, _TASKS_SET> {
+    pub fn task_set(&self) -> Task {
         let g = unsafe { &*pac::GPIOTE::ptr() };
-        &g.tasks_set[self.ch.number()]
+        Task::from_reg(&g.tasks_set[self.ch.number()])
     }
 }
 
-/// GPIO input driver with support
+/// GPIOTE port input driver
 pub struct PortInput<'d, T: GpioPin> {
     pin: Input<'d, T>,
 }

embassy-nrf/src/ppi.rs

@@ -9,13 +9,106 @@
 //! On nRF52 devices, there is also a fork task endpoint, where the user can configure one more task
 //! to be triggered by the same event, even fixed PPI channels have a configurable fork task.
 
-use embassy_extras::impl_unborrow;
+use core::marker::PhantomData;
+use core::ptr::NonNull;
+use embassy::util::PeripheralBorrow;
+use embassy_extras::{impl_unborrow, unborrow};
 
-use crate::peripherals;
+use crate::{pac, peripherals};
+
+// ======================
+//       driver
+
+pub struct Ppi<'d, C: Channel> {
+    ch: C,
+    phantom: PhantomData<&'d mut C>,
+}
+
+impl<'d, C: Channel> Ppi<'d, C> {
+    pub fn new(ch: impl PeripheralBorrow<Target = C> + 'd) -> Self {
+        unborrow!(ch);
+        let mut this = Self {
+            ch,
+            phantom: PhantomData,
+        };
+        #[cfg(not(feature = "51"))]
+        this.clear_fork_task();
+        this
+    }
+
+    /// Enables the channel.
+    pub fn enable(&mut self) {
+        let r = unsafe { &*pac::PPI::ptr() };
+        r.chenset
+            .write(|w| unsafe { w.bits(1 << self.ch.number()) });
+    }
+
+    /// Disables the channel.
+    pub fn disable(&mut self) {
+        let r = unsafe { &*pac::PPI::ptr() };
+        r.chenclr
+            .write(|w| unsafe { w.bits(1 << self.ch.number()) });
+    }
+
+    #[cfg(not(feature = "51"))]
+    /// Sets the fork task that must be triggered when the configured event occurs. The user must
+    /// provide a reference to the task.
+    pub fn set_fork_task(&mut self, task: Task) {
+        let r = unsafe { &*pac::PPI::ptr() };
+        r.fork[self.ch.number()]
+            .tep
+            .write(|w| unsafe { w.bits(task.0.as_ptr() as u32) })
+    }
+
+    #[cfg(not(feature = "51"))]
+    /// Clear the fork task endpoint. Previously set task will no longer be triggered.
+    pub fn clear_fork_task(&mut self) {
+        let r = unsafe { &*pac::PPI::ptr() };
+        r.fork[self.ch.number()].tep.write(|w| unsafe { w.bits(0) })
+    }
+}
+
+impl<'d, C: Channel> Drop for Ppi<'d, C> {
+    fn drop(&mut self) {
+        self.disable()
+    }
+}
+
+impl<'d, C: ConfigurableChannel> Ppi<'d, C> {
+    /// Sets the task to be triggered when the configured event occurs.
+    pub fn set_task(&mut self, task: Task) {
+        let r = unsafe { &*pac::PPI::ptr() };
+        r.ch[self.ch.number()]
+            .tep
+            .write(|w| unsafe { w.bits(task.0.as_ptr() as u32) })
+    }
+
+    /// Sets the event that will trigger the chosen task(s).
+    pub fn set_event(&mut self, event: Event) {
+        let r = unsafe { &*pac::PPI::ptr() };
+        r.ch[self.ch.number()]
+            .eep
+            .write(|w| unsafe { w.bits(event.0.as_ptr() as u32) })
+    }
+}
 
 // ======================
 //       traits
 
+pub struct Task(pub NonNull<()>);
+impl Task {
+    pub(crate) fn from_reg<T>(reg: &T) -> Self {
+        Self(unsafe { NonNull::new_unchecked(reg as *const _ as *mut ()) })
+    }
+}
+
+pub struct Event(pub NonNull<()>);
+impl Event {
+    pub(crate) fn from_reg<T>(reg: &T) -> Self {
+        Self(unsafe { NonNull::new_unchecked(reg as *const _ as *mut ()) })
+    }
+}
+
 mod sealed {
     pub trait ConfigurableChannel {}
     pub trait Channel {}