Implement embedded_hal::pwm::SetDutyCycle of embedded-hal 1.0

Also add a new example pwm_blink_embedded_hal_1 which uses this
trait, to have a minimal test case.

rp2040-hal/Cargo.toml

@@ -180,6 +180,10 @@ required-features = ["critical-section-impl"]
 name = "pwm_blink"
 required-features = ["critical-section-impl"]
 
+[[example]]
+name = "pwm_blink_embedded_hal_1"
+required-features = ["critical-section-impl", "eh1_0_alpha"]
+
 [[example]]
 name = "rom_funcs"
 required-features = ["critical-section-impl"]

rp2040-hal/examples/pwm_blink_embedded_hal_1.rs

@@ -0,0 +1,122 @@
+//! # PWM Blink Example
+//!
+//! If you have an LED connected to pin 25, it will fade the LED using the PWM
+//! peripheral.
+//!
+//! It may need to be adapted to your particular board layout and/or pin assignment.
+//!
+//! See the `Cargo.toml` file for Copyright and license details.
+
+#![no_std]
+#![no_main]
+
+// Ensure we halt the program on panic (if we don't mention this crate it won't
+// be linked)
+use panic_halt as _;
+
+// Alias for our HAL crate
+use rp2040_hal as hal;
+
+// Some traits we need
+use eh1_0_alpha::pwm::SetDutyCycle;
+use rp2040_hal::clocks::Clock;
+
+// A shorter alias for the Peripheral Access Crate, which provides low-level
+// register access
+use hal::pac;
+
+/// The linker will place this boot block at the start of our program image. We
+/// need this to help the ROM bootloader get our code up and running.
+/// Note: This boot block is not necessary when using a rp-hal based BSP
+/// as the BSPs already perform this step.
+#[link_section = ".boot2"]
+#[used]
+pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_GENERIC_03H;
+
+/// The minimum PWM value (i.e. LED brightness) we want
+const LOW: u16 = 0;
+
+/// The maximum PWM value (i.e. LED brightness) we want
+const HIGH: u16 = 25000;
+
+/// External high-speed crystal on the Raspberry Pi Pico board is 12 MHz. Adjust
+/// if your board has a different frequency
+const XTAL_FREQ_HZ: u32 = 12_000_000u32;
+
+/// Entry point to our bare-metal application.
+///
+/// The `#[rp2040_hal::entry]` macro ensures the Cortex-M start-up code calls this function
+/// as soon as all global variables and the spinlock are initialised.
+///
+/// The function configures the RP2040 peripherals, then fades the LED in an
+/// infinite loop.
+#[rp2040_hal::entry]
+fn main() -> ! {
+    // Grab our singleton objects
+    let mut pac = pac::Peripherals::take().unwrap();
+    let core = pac::CorePeripherals::take().unwrap();
+
+    // Set up the watchdog driver - needed by the clock setup code
+    let mut watchdog = hal::Watchdog::new(pac.WATCHDOG);
+
+    // Configure the clocks
+    //
+    // The default is to generate a 125 MHz system clock
+    let clocks = hal::clocks::init_clocks_and_plls(
+        XTAL_FREQ_HZ,
+        pac.XOSC,
+        pac.CLOCKS,
+        pac.PLL_SYS,
+        pac.PLL_USB,
+        &mut pac.RESETS,
+        &mut watchdog,
+    )
+    .ok()
+    .unwrap();
+
+    // The single-cycle I/O block controls our GPIO pins
+    let sio = hal::Sio::new(pac.SIO);
+
+    // Set the pins up according to their function on this particular board
+    let pins = hal::gpio::Pins::new(
+        pac.IO_BANK0,
+        pac.PADS_BANK0,
+        sio.gpio_bank0,
+        &mut pac.RESETS,
+    );
+
+    // The delay object lets us wait for specified amounts of time (in
+    // milliseconds)
+    let mut delay = cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz());
+
+    // Init PWMs
+    let mut pwm_slices = hal::pwm::Slices::new(pac.PWM, &mut pac.RESETS);
+
+    // Configure PWM4
+    let pwm = &mut pwm_slices.pwm4;
+    pwm.set_ph_correct();
+    pwm.enable();
+
+    // Output channel B on PWM4 to GPIO 25
+    let channel = &mut pwm.channel_b;
+    channel.output_to(pins.gpio25);
+
+    // Infinite loop, fading LED up and down
+    loop {
+        // Ramp brightness up
+        for i in (LOW..=HIGH).skip(100) {
+            delay.delay_us(8);
+            channel.set_duty_cycle(i).unwrap();
+        }
+
+        // Ramp brightness down
+        for i in (LOW..=HIGH).rev().skip(100) {
+            delay.delay_us(8);
+            channel.set_duty_cycle(i).unwrap();
+        }
+
+        delay.delay_ms(500);
+    }
+}
+
+// End of file

rp2040-hal/src/pwm/mod.rs

@@ -76,8 +76,10 @@
 //! min_config() leaves those registers in the state they were before it was called (Careful, this can lead to unexpected behavior)
 //! It's recommended to only call min_config() after calling default_config() on a pin that shares a PWM block.
 
-use core::marker::PhantomData;
+use core::{convert::Infallible, marker::PhantomData};
 
+#[cfg(feature = "eh1_0_alpha")]
+use eh1_0_alpha::pwm::{ErrorType, SetDutyCycle};
 use embedded_dma::Word;
 use embedded_hal::PwmPin;
 
@@ -652,6 +654,23 @@ impl<S: AnySlice> PwmPin for Channel<S, A> {
     }
 }
 
+#[cfg(feature = "eh1_0_alpha")]
+impl<S: AnySlice> ErrorType for Channel<S, B> {
+    type Error = Infallible;
+}
+
+#[cfg(feature = "eh1_0_alpha")]
+impl<S: AnySlice> SetDutyCycle for Channel<S, B> {
+    fn max_duty_cycle(&self) -> u16 {
+        self.get_max_duty()
+    }
+
+    fn set_duty_cycle(&mut self, duty: u16) -> Result<(), Self::Error> {
+        self.set_duty(duty);
+        Ok(())
+    }
+}
+
 impl<S: AnySlice> PwmPin for Channel<S, B> {
     type Duty = u16;