PWM example

Author: romancardenas

e310x-hal/src/prelude.rs

@@ -14,6 +14,7 @@ pub use embedded_hal::{
     delay::DelayNs,
     digital::{InputPin, OutputPin, StatefulOutputPin},
     i2c::I2c,
+    pwm::SetDutyCycle,
     spi::{SpiBus, SpiDevice},
 };
 

e310x-hal/src/pwm.rs

@@ -3,23 +3,23 @@
 //! You can use the `PWM` with these [Pwm] instances
 //!
 //! # PWM0 - 8 bit period and duty
-//! - Channel 1: Pin 9 IOF1
-//! - Channel 2: Pin 10 IOF1
-//! - Channel 3: Pin 11 IOF1
+//! - Channel 1: Pin 1 IOF1
+//! - Channel 2: Pin 2 IOF1
+//! - Channel 3: Pin 3 IOF1
 //!
 //! # PWM1 - 16 bit period and duty
-//! - Channel 1: Pin 3 IOF1
-//! - Channel 2: Pin 5 IOF1
-//! - Channel 3: Pin 6 IOF1
+//! - Channel 1: Pin 19 IOF1
+//! - Channel 2: Pin 21 IOF1
+//! - Channel 3: Pin 22 IOF1
 //!
 //! # PWM2 - 16 bit period and duty
-//! - Channel 1: Pin 17 IOF1
-//! - Channel 2: Pin 18 IOF1
-//! - Channel 3: Pin 19 IOF1
-
-use core::{marker::PhantomData, ops::Deref};
+//! - Channel 1: Pin 11 IOF1
+//! - Channel 2: Pin 12 IOF1
+//! - Channel 3: Pin 13 IOF1
 
+use core::ops::Deref;
 use e310x::{pwm0, Pwm0, Pwm1, Pwm2};
+use embedded_hal::pwm::{ErrorKind, ErrorType, SetDutyCycle};
 
 /// PWM comparator index
 #[derive(Copy, Clone)]
@@ -33,71 +33,53 @@ pub enum CmpIndex {
 }
 
 /// PWM pin
-pub trait Pin<PWM>: private::Sealed {
+pub trait Pin<PWM: PwmX>: private::Sealed {
     /// Channel index associated with the pin
     const CMP_INDEX: CmpIndex;
 }
 
 mod pwm_impl {
     use super::{CmpIndex, Pin, Pwm0, Pwm1, Pwm2};
-    use crate::gpio::{gpio0, NoInvert, IOF1};
+    use crate::gpio::{gpio0, Invert, IOF1};
 
     // PWM0
-    impl Pin<Pwm0> for gpio0::Pin1<IOF1<NoInvert>> {
+    impl Pin<Pwm0> for gpio0::Pin1<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp1;
     }
-    impl Pin<Pwm0> for gpio0::Pin2<IOF1<NoInvert>> {
+    impl Pin<Pwm0> for gpio0::Pin2<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp2;
     }
-    impl Pin<Pwm0> for gpio0::Pin3<IOF1<NoInvert>> {
+    impl Pin<Pwm0> for gpio0::Pin3<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp3;
     }
 
     // PWM1
-    impl Pin<Pwm1> for gpio0::Pin19<IOF1<NoInvert>> {
+    impl Pin<Pwm1> for gpio0::Pin19<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp1;
     }
-    impl Pin<Pwm1> for gpio0::Pin21<IOF1<NoInvert>> {
+    impl Pin<Pwm1> for gpio0::Pin21<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp2;
     }
-    impl Pin<Pwm1> for gpio0::Pin22<IOF1<NoInvert>> {
+    impl Pin<Pwm1> for gpio0::Pin22<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp3;
     }
 
     // PWM2
-    impl Pin<Pwm2> for gpio0::Pin11<IOF1<NoInvert>> {
+    impl Pin<Pwm2> for gpio0::Pin11<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp1;
     }
-    impl Pin<Pwm2> for gpio0::Pin12<IOF1<NoInvert>> {
+    impl Pin<Pwm2> for gpio0::Pin12<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp2;
     }
-    impl Pin<Pwm2> for gpio0::Pin13<IOF1<NoInvert>> {
+    impl Pin<Pwm2> for gpio0::Pin13<IOF1<Invert>> {
         const CMP_INDEX: CmpIndex = CmpIndex::Cmp3;
     }
 }
 
-/// PWM channel
-#[derive(Copy, Clone)]
-pub struct Channel<PWM> {
-    _pwm: PhantomData<PWM>,
-    cmp_index: CmpIndex,
-}
-
-impl<PWM> Channel<PWM> {
-    /// Constructs a PWM channel from a PWM pin for use with [Pwm]
-    pub fn from<PIN: Pin<PWM>>(_: PIN) -> Channel<PWM> {
-        Channel {
-            _pwm: PhantomData,
-            cmp_index: PIN::CMP_INDEX,
-        }
-    }
-}
-
 /// PwmX trait extends the PWM peripherals
 #[doc(hidden)]
 pub trait PwmX: Deref<Target = pwm0::RegisterBlock> + private::Sealed {
     type CmpWidth: Ord;
-    fn peripheral() -> Self;
     fn bits_from_cmp_width(other: Self::CmpWidth) -> u32;
     fn bits_into_cmp_width(other: u32) -> Self::CmpWidth;
 }
@@ -106,9 +88,6 @@ macro_rules! pwmx_impl {
     ($PWM:ident,$CMP_WIDTH:ident) => {
         impl PwmX for $PWM {
             type CmpWidth = $CMP_WIDTH;
-            fn peripheral() -> Self {
-                unsafe { Self::steal() }
-            }
             fn bits_from_cmp_width(other: Self::CmpWidth) -> u32 {
                 other as u32
             }
@@ -152,103 +131,148 @@ impl<PWM: PwmX> Pwm<PWM> {
         Self { pwm }
     }
 
+    /// Frees the PWM device
+    pub fn free(self) -> PWM {
+        self.pwm
+    }
+
+    /// Returns the period of the PWM
+    pub fn get_period(&self) -> PWM::CmpWidth {
+        PWM::bits_into_cmp_width(self.pwm.cmp0().read().bits())
+    }
+
+    /// Sets the period of the PWM
+    pub fn set_period(&mut self, period: PWM::CmpWidth) {
+        let period = PWM::bits_from_cmp_width(period);
+        self.pwm.count().reset();
+        self.pwm.cmp0().write(|w| unsafe { w.bits(period) });
+    }
+
+    /// Returns the duty cycle of the PWM
+    fn get_duty(&self, cmp_index: CmpIndex) -> PWM::CmpWidth {
+        let duty = match cmp_index {
+            CmpIndex::Cmp1 => self.pwm.cmp1().read().bits(),
+            CmpIndex::Cmp2 => self.pwm.cmp2().read().bits(),
+            CmpIndex::Cmp3 => self.pwm.cmp3().read().bits(),
+        };
+        PWM::bits_into_cmp_width(duty)
+    }
+
+    /// Sets the duty cycle of the PWM
+    fn set_duty(&self, cmp_index: CmpIndex, duty: PWM::CmpWidth) {
+        let duty = PWM::bits_from_cmp_width(duty.min(self.get_period()));
+        match cmp_index {
+            CmpIndex::Cmp1 => self.pwm.cmp1().write(|w| unsafe { w.bits(duty) }),
+            CmpIndex::Cmp2 => self.pwm.cmp2().write(|w| unsafe { w.bits(duty) }),
+            CmpIndex::Cmp3 => self.pwm.cmp3().write(|w| unsafe { w.bits(duty) }),
+        }
+    }
+
     /// Enables the PWM channel
-    pub fn enable(&mut self, channel: &Channel<PWM>) {
-        match channel.cmp_index {
+    fn enable(&self, cmp_index: CmpIndex) {
+        match cmp_index {
             CmpIndex::Cmp1 => self.pwm.cmp1().write(|w| unsafe { w.bits(u32::MAX) }),
             CmpIndex::Cmp2 => self.pwm.cmp2().write(|w| unsafe { w.bits(u32::MAX) }),
             CmpIndex::Cmp3 => self.pwm.cmp3().write(|w| unsafe { w.bits(u32::MAX) }),
         }
     }
 
     /// Disables the PWM channel
-    pub fn disable(&mut self, channel: &Channel<PWM>) {
-        match channel.cmp_index {
+    fn disable(&self, cmp_index: CmpIndex) {
+        match cmp_index {
             CmpIndex::Cmp1 => self.pwm.cmp1().reset(),
             CmpIndex::Cmp2 => self.pwm.cmp2().reset(),
             CmpIndex::Cmp3 => self.pwm.cmp3().reset(),
         }
     }
 
+    /// Returns the PWM channel associated with the given index
+    pub fn channel<PIN: Pin<PWM>>(&self, pin: PIN) -> Channel<'_, PWM, PIN> {
+        Channel { pwm: self, pin }
+    }
+}
+
+/// PWM channel
+pub struct Channel<'a, PWM, PIN> {
+    pwm: &'a Pwm<PWM>,
+    pin: PIN,
+}
+
+impl<'a, PWM, PIN> Channel<'a, PWM, PIN> {
+    /// Frees the PWM channel
+    pub fn free(self) -> PIN {
+        self.pin
+    }
+}
+
+impl<'a, PWM: PwmX, PIN: Pin<PWM>> Channel<'a, PWM, PIN> {
     /// Returns the period of the PWM
     pub fn get_period(&self) -> PWM::CmpWidth {
-        PWM::bits_into_cmp_width(self.pwm.cmp0().read().bits())
+        self.pwm.get_period()
+    }
+
+    /// Returns the maximum duty cycle of the PWM (equal to the period)
+    pub fn max_duty(&self) -> PWM::CmpWidth {
+        self.pwm.get_period()
     }
 
     /// Returns the duty cycle of the PWM
-    pub fn get_duty(&self, channel: &Channel<PWM>) -> PWM::CmpWidth {
-        let duty = match channel.cmp_index {
-            CmpIndex::Cmp1 => self.pwm.cmp1().read().bits(),
-            CmpIndex::Cmp2 => self.pwm.cmp2().read().bits(),
-            CmpIndex::Cmp3 => self.pwm.cmp3().read().bits(),
-        };
-        PWM::bits_into_cmp_width(duty)
+    pub fn get_duty(&self) -> PWM::CmpWidth {
+        self.pwm.get_duty(PIN::CMP_INDEX)
     }
 
-    /// Returns the maximum duty cycle of the PWM (equal to the period)
-    pub fn get_max_duty(&self) -> PWM::CmpWidth {
-        self.get_period()
+    /// Sets the duty cycle to 100%
+    pub fn enable(&mut self) {
+        self.pwm.enable(PIN::CMP_INDEX);
     }
 
-    /// Sets the duty cycle of the PWM
-    pub fn set_duty(&mut self, channel: &Channel<PWM>, duty: PWM::CmpWidth) {
-        let duty = PWM::bits_from_cmp_width(duty.min(self.get_max_duty()));
-        match channel.cmp_index {
-            CmpIndex::Cmp1 => self.pwm.cmp1().write(|w| unsafe { w.bits(duty) }),
-            CmpIndex::Cmp2 => self.pwm.cmp2().write(|w| unsafe { w.bits(duty) }),
-            CmpIndex::Cmp3 => self.pwm.cmp3().write(|w| unsafe { w.bits(duty) }),
-        }
+    /// Sets the duty cycle to 0%
+    pub fn disable(&mut self) {
+        self.pwm.disable(PIN::CMP_INDEX);
     }
 
-    /// Sets the period of the PWM
-    pub fn set_period(&mut self, period: PWM::CmpWidth) {
-        let period = PWM::bits_from_cmp_width(period);
-        self.pwm.count().reset();
-        self.pwm.cmp0().write(|w| unsafe { w.bits(period) });
+    /// Sets the duty cycle of the PWM
+    pub fn set_duty(&mut self, duty: PWM::CmpWidth) {
+        self.pwm.set_duty(PIN::CMP_INDEX, duty);
     }
 }
 
-impl<PWM: PwmX> embedded_hal::pwm::ErrorType for Channel<PWM> {
-    type Error = embedded_hal::pwm::ErrorKind;
+impl<'a, PWM: PwmX, PIN: Pin<PWM>> ErrorType for Channel<'a, PWM, PIN> {
+    type Error = ErrorKind;
 }
 
-impl<PWM: PwmX> embedded_hal::pwm::SetDutyCycle for Channel<PWM> {
+impl<'a, PWM: PwmX, PIN: Pin<PWM>> SetDutyCycle for Channel<'a, PWM, PIN> {
     fn max_duty_cycle(&self) -> u16 {
-        let pwm: Pwm<PWM> = Pwm {
-            pwm: PWM::peripheral(),
-        };
-        PWM::bits_from_cmp_width(pwm.get_max_duty()) as _
+        PWM::bits_from_cmp_width(self.max_duty()) as _
     }
 
     fn set_duty_cycle(&mut self, duty: u16) -> Result<(), Self::Error> {
-        let mut pwm: Pwm<PWM> = Pwm {
-            pwm: PWM::peripheral(),
-        };
-        pwm.set_duty(self, PWM::bits_into_cmp_width(duty as _));
+        self.pwm
+            .set_duty(PIN::CMP_INDEX, PWM::bits_into_cmp_width(duty as _));
         Ok(())
     }
 }
 
 mod private {
     use super::{Pwm0, Pwm1, Pwm2};
-    use crate::gpio::{gpio0, NoInvert, IOF1};
+    use crate::gpio::{gpio0, Invert, IOF1};
     pub trait Sealed {}
 
     // PWM0
     impl Sealed for Pwm0 {}
-    impl Sealed for gpio0::Pin1<IOF1<NoInvert>> {}
-    impl Sealed for gpio0::Pin2<IOF1<NoInvert>> {}
-    impl Sealed for gpio0::Pin3<IOF1<NoInvert>> {}
+    impl Sealed for gpio0::Pin1<IOF1<Invert>> {}
+    impl Sealed for gpio0::Pin2<IOF1<Invert>> {}
+    impl Sealed for gpio0::Pin3<IOF1<Invert>> {}
 
     // PWM1
     impl Sealed for Pwm1 {}
-    impl Sealed for gpio0::Pin19<IOF1<NoInvert>> {}
-    impl Sealed for gpio0::Pin21<IOF1<NoInvert>> {}
-    impl Sealed for gpio0::Pin22<IOF1<NoInvert>> {}
+    impl Sealed for gpio0::Pin19<IOF1<Invert>> {}
+    impl Sealed for gpio0::Pin21<IOF1<Invert>> {}
+    impl Sealed for gpio0::Pin22<IOF1<Invert>> {}
 
     // PWM2
     impl Sealed for Pwm2 {}
-    impl Sealed for gpio0::Pin11<IOF1<NoInvert>> {}
-    impl Sealed for gpio0::Pin12<IOF1<NoInvert>> {}
-    impl Sealed for gpio0::Pin13<IOF1<NoInvert>> {}
+    impl Sealed for gpio0::Pin11<IOF1<Invert>> {}
+    impl Sealed for gpio0::Pin12<IOF1<Invert>> {}
+    impl Sealed for gpio0::Pin13<IOF1<Invert>> {}
 }

hifive1-examples/examples/button_poll.rs

@@ -1,4 +1,9 @@
 //! Example of polling a button and turning on a LED when the button is pressed.
+//!
+//! # Hardware
+//!
+//! - HiFive1 or RED-V board
+//! - A button connected to pin 9
 
 #![no_std]
 #![no_main]