embassy_rp: implement pwm traits from embedded_hal

• Update crate versions • Implement embedded-hal PWM traits • Add TB6612FNG motor driver example

embassy-rp/Cargo.toml

@@ -118,18 +118,18 @@ embassy-usb-driver = {version = "0.1.0", path = "../embassy-usb-driver" }
 atomic-polyfill = "1.0.1"
 defmt = { version = "0.3", optional = true }
 log = { version = "0.4.14", optional = true }
-nb = "1.0.0"
+nb = "1.1.0"
 cfg-if = "1.0.0"
 cortex-m-rt = ">=0.6.15,<0.8"
 cortex-m = "0.7.6"
-critical-section = "1.1"
+critical-section = "1.2.0"
 chrono = { version = "0.4", default-features = false, optional = true }
 embedded-io = { version = "0.6.1" }
 embedded-io-async = { version = "0.6.1" }
 embedded-storage = { version = "0.3" }
 embedded-storage-async = { version = "0.4.1" }
 rand_core = "0.6.4"
-fixed = "1.23.1"
+fixed = "1.28.0"
 
 rp-pac = { git = "https://github.com/embassy-rs/rp-pac.git", rev = "a7f42d25517f7124ad3b4ed492dec8b0f50a0e6c", feature = ["rt"] }
 
@@ -141,7 +141,7 @@ embedded-hal-nb = { version = "1.0" }
 pio-proc = {version= "0.2" }
 pio = {version= "0.2.1" }
 rp2040-boot2 = "0.3"
-document-features = "0.2.7"
+document-features = "0.2.10"
 sha2-const-stable = "0.1"
 rp-binary-info = { version = "0.1.0", optional = true }
 smart-leds = "0.4.0"

embassy-rp/src/pwm.rs

@@ -1,6 +1,7 @@
 //! Pulse Width Modulation (PWM)
 
 use embassy_hal_internal::{into_ref, Peripheral, PeripheralRef};
+use embedded_hal_1::pwm::{Error, ErrorKind, ErrorType, SetDutyCycle};
 use fixed::traits::ToFixed;
 use fixed::FixedU16;
 use pac::pwm::regs::{ChDiv, Intr};
@@ -80,6 +81,21 @@ impl From<InputMode> for Divmode {
     }
 }
 
+/// PWM error.
+#[derive(Debug)]
+pub enum PwmError {
+    /// Invalid Duty Cycle.
+    InvalidDutyCycle,
+}
+
+impl Error for PwmError {
+    fn kind(&self) -> ErrorKind {
+        match self {
+            PwmError::InvalidDutyCycle => ErrorKind::Other,
+        }
+    }
+}
+
 /// PWM driver.
 pub struct Pwm<'d> {
     pin_a: Option<PeripheralRef<'d, AnyPin>>,
@@ -87,6 +103,32 @@ pub struct Pwm<'d> {
     slice: usize,
 }
 
+impl<'d> ErrorType for Pwm<'d> {
+    type Error = PwmError;
+}
+
+impl<'d> SetDutyCycle for Pwm<'d> {
+    fn max_duty_cycle(&self) -> u16 {
+        pac::PWM.ch(self.slice).top().read().top()
+    }
+
+    fn set_duty_cycle(&mut self, duty: u16) -> Result<(), Self::Error> {
+        info!("duty {}",&duty);
+        let max_duty = self.max_duty_cycle();
+        info!("max duty {}", &max_duty);
+        if duty > max_duty {
+            return Err(PwmError::InvalidDutyCycle);
+        }
+
+        let p = pac::PWM.ch(self.slice);
+        p.cc().modify(|w| {
+            w.set_a(duty);
+            w.set_b(duty);
+        });
+        Ok(())
+    }
+}
+
 impl<'d> Pwm<'d> {
     fn new_inner(
         slice: usize,

examples/rp23/Cargo.toml

@@ -30,6 +30,9 @@ serde-json-core = "0.5.1"
 # for assign resources example
 assign-resources = { git = "https://github.com/adamgreig/assign-resources", rev = "94ad10e2729afdf0fd5a77cd12e68409a982f58a" }
 
+# for TB6612FNG example
+tb6612fng = "1.0.0"
+
 #cortex-m = { version = "0.7.6", features = ["critical-section-single-core"] }
 cortex-m = { version = "0.7.6", features = ["inline-asm"] }
 cortex-m-rt = "0.7.0"

examples/rp23/src/bin/pwm_tb6612fng_motor_driver.rs

@@ -0,0 +1,114 @@
+//! # PWM TB6612FNG motor driver
+//! 
+//! This example shows the use of a TB6612FNG motor driver. The driver is built on top of embedded_hal and the example demonstrates how embassy_rp can be used to interact with ist.
+
+#![no_std]
+#![no_main]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_rp::block::ImageDef;
+use embassy_rp::config::Config;
+use embassy_rp::gpio::Output;
+use embassy_rp::peripherals;
+use embassy_rp::gpio;
+use embassy_rp::pwm;
+use embassy_time::Duration;
+use embassy_time::Timer;
+use {defmt_rtt as _, panic_probe as _};
+use tb6612fng::{DriveCommand, Motor, Tb6612fng};
+use assign_resources::assign_resources;
+
+/// Maximum PWM value (fully on)
+const PWM_MAX: u16 = 50000;
+
+/// Minimum PWM value (fully off)
+const PWM_MIN: u16 = 0;
+
+#[link_section = ".start_block"]
+#[used]
+pub static IMAGE_DEF: ImageDef = ImageDef::secure_exe();
+
+assign_resources! {
+    motor: MotorResources {
+        standby_pin: PIN_22,
+        left_slice: PWM_SLICE6,
+        left_pwm_pin: PIN_28,
+        left_forward_pin: PIN_21,
+        left_backward_pin: PIN_20,
+        right_slice: PWM_SLICE5,
+        right_pwm_pin: PIN_27,
+        right_forward_pin: PIN_19,
+        right_backward_pin: PIN_18,
+        },
+}
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let p = embassy_rp::init(Config::default());
+    let s = split_resources!(p);
+    let r = s.motor;
+
+    // we need a standby output and two motors to construct a full TB6612FNG
+
+    // standby pin
+    let stby = Output::new(r.standby_pin, gpio::Level::Low);
+
+    // motor A, here defined to be the left motor
+    let left_fwd = gpio::Output::new(r.left_forward_pin, gpio::Level::Low);
+    let left_bckw = gpio::Output::new(r.left_backward_pin, gpio::Level::Low);
+    let mut left_speed = pwm::Config::default();
+    left_speed.top = PWM_MAX;
+    left_speed.compare_a = PWM_MIN;
+    let left_pwm = pwm::Pwm::new_output_a(r.left_slice, r.left_pwm_pin, left_speed);
+    let left_motor = Motor::new(left_fwd, left_bckw, left_pwm).unwrap();
+
+    // motor B, here defined to be the right motor
+    let right_fwd = gpio::Output::new(r.right_forward_pin, gpio::Level::Low);
+    let right_bckw = gpio::Output::new(r.right_backward_pin, gpio::Level::Low);
+    let mut right_speed = pwm::Config::default();
+    right_speed.top = PWM_MAX;
+    right_speed.compare_b = PWM_MIN;
+    let right_pwm = pwm::Pwm::new_output_b(r.right_slice, r.right_pwm_pin, right_speed);
+    let right_motor = Motor::new(right_fwd, right_bckw, right_pwm).unwrap();
+
+    // construct the motor driver
+    let mut control = Tb6612fng::new(left_motor, right_motor, stby).unwrap();
+
+    loop {
+        // wake up the motor driver
+        info!("end standby");
+        control.disable_standby().unwrap();
+        Timer::after(Duration::from_millis(100)).await;
+
+        // drive a straight line forward at 20% speed for 5s
+        info!("drive straight");
+        control.motor_a.drive(DriveCommand::Forward(20)).unwrap();
+        control.motor_b.drive(DriveCommand::Forward(20)).unwrap();
+        Timer::after(Duration::from_secs(5)).await;
+
+        // coast for 2s
+        info!("coast");
+        control.motor_a.drive(DriveCommand::Stop).unwrap();
+        control.motor_b.drive(DriveCommand::Stop).unwrap();
+        Timer::after(Duration::from_secs(2)).await;
+
+        // actively brake
+        info!("brake");	
+        control.motor_a.drive(DriveCommand::Brake).unwrap();
+        control.motor_b.drive(DriveCommand::Brake).unwrap();
+        Timer::after(Duration::from_secs(1)).await;
+
+        // slowly turn for 3s
+        info!( "turn");
+        control.motor_a.drive(DriveCommand::Backward(10)).unwrap();
+        control.motor_b.drive(DriveCommand::Forward(10)).unwrap();
+        Timer::after(Duration::from_secs(3)).await;
+
+        // and put the driver in standby mode and wait for 5s
+        info!( "standby");
+        control.enable_standby().unwrap();
+        Timer::after(Duration::from_secs(5)).await;
+    }
+}
+