feat: add 0x03_button_rust driver with 8 unit tests

2026-05-26 17:28:25 +02:00 · 2026-03-25 11:37:45 -04:00
parent e5f6bb7f15
commit 12da31297e
18 changed files with 1677 additions and 0 deletions
@@ -0,0 +1,254 @@
+//! @file button.rs
+//! @brief Implementation of the push-button GPIO input driver with debounce
+//! @author Kevin Thomas
+//! @date 2025
+//!
+//! MIT License
+//!
+//! Copyright (c) 2025 Kevin Thomas
+//!
+//! Permission is hereby granted, free of charge, to any person obtaining a copy
+//! of this software and associated documentation files (the "Software"), to deal
+//! in the Software without restriction, including without limitation the rights
+//! to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//! copies of the Software, and to permit persons to whom the Software is
+//! furnished to do so, subject to the following conditions:
+//!
+//! The above copyright notice and this permission notice shall be included in
+//! all copies or substantial portions of the Software.
+//!
+//! THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//! IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//! FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//! AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//! LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//! OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//! SOFTWARE.
+
+use embedded_hal::digital::{InputPin, OutputPin, StatefulOutputPin};
+
+/// Push-button GPIO input driver with debounce.
+pub struct ButtonDriver<B: InputPin, D: FnMut(u32)> {
+    btn_pin: B,
+    debounce_ms: u32,
+    delay_fn: D,
+}
+
+impl<B: InputPin, D: FnMut(u32)> ButtonDriver<B, D> {
+    /// Initialize a GPIO pin as an active-low button input with pull-up.
+    ///
+    /// The pin reads logic high when the button is open and logic low when
+    /// the button connects the pin to GND.
+    ///
+    /// # Arguments
+    ///
+    /// * `btn_pin` - GPIO pin configured as input with pull-up.
+    /// * `debounce_ms` - Debounce settling time in milliseconds (e.g. 20).
+    /// * `delay_fn` - Closure that sleeps for the given number of milliseconds.
+    ///
+    /// # Returns
+    ///
+    /// A new ButtonDriver instance.
+    pub fn init(btn_pin: B, debounce_ms: u32, delay_fn: D) -> Self {
+        Self { btn_pin, debounce_ms, delay_fn }
+    }
+
+    /// Confirm a raw active-low pin read by waiting for the debounce period.
+    ///
+    /// After an initial low reading on the pin, this helper re-samples the pin
+    /// after debounce_ms milliseconds to confirm the reading is stable.
+    ///
+    /// # Returns
+    ///
+    /// `true` if the pin is still low after the debounce delay.
+    fn debounce_confirm(&mut self) -> bool {
+        (self.delay_fn)(self.debounce_ms);
+        self.btn_pin.is_low().unwrap()
+    }
+
+    /// Read the debounced state of the button.
+    ///
+    /// Returns true only when the pin reads low continuously for the debounce
+    /// period configured in init(). This prevents mechanical contact bounce
+    /// from registering as multiple rapid presses.
+    ///
+    /// # Returns
+    ///
+    /// `true` if the button is firmly pressed, `false` if released.
+    pub fn is_pressed(&mut self) -> bool {
+        if self.btn_pin.is_low().unwrap() {
+            return self.debounce_confirm();
+        }
+        false
+    }
+}
+
+/// Indicator LED driver that owns a single output pin.
+pub struct ButtonLed<L: OutputPin + StatefulOutputPin> {
+    led_pin: L,
+}
+
+impl<L: OutputPin + StatefulOutputPin> ButtonLed<L> {
+    /// Initialize a GPIO pin as a push-pull digital output for an indicator LED.
+    ///
+    /// Configures the output and drives it low (LED off).
+    ///
+    /// # Arguments
+    ///
+    /// * `led_pin` - GPIO pin configured as a digital output.
+    ///
+    /// # Returns
+    ///
+    /// A new ButtonLed instance.
+    pub fn init(mut led_pin: L) -> Self {
+        led_pin.set_low().unwrap();
+        Self { led_pin }
+    }
+
+    /// Set the indicator LED state.
+    ///
+    /// Drives the output pin high (LED on) or low (LED off).
+    ///
+    /// # Arguments
+    ///
+    /// * `on` - `true` to turn the LED on, `false` to turn it off.
+    pub fn set(&mut self, on: bool) {
+        if on {
+            self.led_pin.set_high().unwrap();
+        } else {
+            self.led_pin.set_low().unwrap();
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use core::convert::Infallible;
+    use embedded_hal::digital::ErrorType;
+
+    struct MockInputPin {
+        low: bool,
+    }
+
+    impl MockInputPin {
+        fn new(low: bool) -> Self {
+            Self { low }
+        }
+    }
+
+    impl ErrorType for MockInputPin {
+        type Error = Infallible;
+    }
+
+    impl InputPin for MockInputPin {
+        fn is_high(&mut self) -> Result<bool, Self::Error> {
+            Ok(!self.low)
+        }
+        fn is_low(&mut self) -> Result<bool, Self::Error> {
+            Ok(self.low)
+        }
+    }
+
+    struct MockOutputPin {
+        state: bool,
+    }
+
+    impl MockOutputPin {
+        fn new() -> Self {
+            Self { state: false }
+        }
+    }
+
+    impl ErrorType for MockOutputPin {
+        type Error = Infallible;
+    }
+
+    impl OutputPin for MockOutputPin {
+        fn set_low(&mut self) -> Result<(), Self::Error> {
+            self.state = false;
+            Ok(())
+        }
+        fn set_high(&mut self) -> Result<(), Self::Error> {
+            self.state = true;
+            Ok(())
+        }
+    }
+
+    impl StatefulOutputPin for MockOutputPin {
+        fn is_set_high(&mut self) -> Result<bool, Self::Error> {
+            Ok(self.state)
+        }
+        fn is_set_low(&mut self) -> Result<bool, Self::Error> {
+            Ok(!self.state)
+        }
+        fn toggle(&mut self) -> Result<(), Self::Error> {
+            self.state = !self.state;
+            Ok(())
+        }
+    }
+
+    fn noop_delay(_ms: u32) {}
+
+    #[test]
+    fn is_pressed_when_low_and_confirmed() {
+        let pin = MockInputPin::new(true);
+        let mut drv = ButtonDriver::init(pin, 20, noop_delay);
+        assert!(drv.is_pressed());
+    }
+
+    #[test]
+    fn is_not_pressed_when_high() {
+        let pin = MockInputPin::new(false);
+        let mut drv = ButtonDriver::init(pin, 20, noop_delay);
+        assert!(!drv.is_pressed());
+    }
+
+    #[test]
+    fn debounce_ms_stored() {
+        let pin = MockInputPin::new(false);
+        let drv = ButtonDriver::init(pin, 50, noop_delay);
+        assert_eq!(drv.debounce_ms, 50);
+    }
+
+    #[test]
+    fn debounce_calls_delay() {
+        let mut called_with: u32 = 0;
+        let pin = MockInputPin::new(true);
+        let mut drv = ButtonDriver::init(pin, 25, |ms| called_with = ms);
+        drv.is_pressed();
+        assert_eq!(called_with, 25);
+    }
+
+    #[test]
+    fn led_init_starts_off() {
+        let led = ButtonLed::init(MockOutputPin::new());
+        assert!(!led.led_pin.state);
+    }
+
+    #[test]
+    fn led_set_on() {
+        let mut led = ButtonLed::init(MockOutputPin::new());
+        led.set(true);
+        assert!(led.led_pin.state);
+    }
+
+    #[test]
+    fn led_set_off() {
+        let mut led = ButtonLed::init(MockOutputPin::new());
+        led.set(true);
+        led.set(false);
+        assert!(!led.led_pin.state);
+    }
+
+    #[test]
+    fn led_set_on_then_off_then_on() {
+        let mut led = ButtonLed::init(MockOutputPin::new());
+        led.set(true);
+        led.set(false);
+        led.set(true);
+        assert!(led.led_pin.state);
+    }
+}
+
+// End of file
@@ -0,0 +1,8 @@
+//! @file lib.rs
+//! @brief Library root for the button driver crate
+//! @author Kevin Thomas
+//! @date 2025
+
+#![no_std]
+
+pub mod button;
@@ -0,0 +1,247 @@
+//! @file main.rs
+//! @brief Button demonstration: debounced press mirrors to LED + UART report
+//! @author Kevin Thomas
+//! @date 2025
+//!
+//! MIT License
+//!
+//! Copyright (c) 2025 Kevin Thomas
+//!
+//! Permission is hereby granted, free of charge, to any person obtaining a copy
+//! of this software and associated documentation files (the "Software"), to deal
+//! in the Software without restriction, including without limitation the rights
+//! to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//! copies of the Software, and to permit persons to whom the Software is
+//! furnished to do so, subject to the following conditions:
+//!
+//! The above copyright notice and this permission notice shall be included in
+//! all copies or substantial portions of the Software.
+//!
+//! THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//! IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//! FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//! AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//! LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//! OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//! SOFTWARE.
+//!
+//! -----------------------------------------------------------------------------
+//!
+//! Demonstrates GPIO input using the button driver (button.rs).
+//! The onboard LED mirrors the button state and every edge transition is
+//! reported over UART.
+//!
+//! Wiring:
+//!   GPIO15 -> One leg of push button
+//!   GND    -> Other leg of push button
+//!   GPIO25 -> Onboard LED (no external wiring needed)
+
+#![no_std]
+#![no_main]
+
+#[allow(dead_code)]
+mod button;
+
+use defmt_rtt as _;
+#[cfg(target_arch = "riscv32")]
+use panic_halt as _;
+#[cfg(target_arch = "arm")]
+use panic_probe as _;
+
+use core::cell::RefCell;
+use fugit::RateExtU32;
+use hal::entry;
+use hal::Clock;
+use hal::gpio::{FunctionNull, FunctionUart, Pin, PullDown, PullNone};
+use hal::uart::{DataBits, Enabled, StopBits, UartConfig, UartPeripheral};
+
+#[cfg(rp2350)]
+use rp235x_hal as hal;
+
+#[cfg(rp2040)]
+use rp2040_hal as hal;
+
+#[unsafe(link_section = ".boot2")]
+#[used]
+#[cfg(rp2040)]
+pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_W25Q080;
+
+#[unsafe(link_section = ".start_block")]
+#[used]
+#[cfg(rp2350)]
+pub static IMAGE_DEF: hal::block::ImageDef = hal::block::ImageDef::secure_exe();
+
+const XTAL_FREQ_HZ: u32 = 12_000_000u32;
+
+const UART_BAUD: u32 = 115_200;
+
+const DEBOUNCE_MS: u32 = 20;
+const POLL_MS: u32 = 10;
+
+type TxPin = Pin<hal::gpio::bank0::Gpio0, FunctionUart, PullNone>;
+type RxPin = Pin<hal::gpio::bank0::Gpio1, FunctionUart, PullNone>;
+type TxPinDefault = Pin<hal::gpio::bank0::Gpio0, FunctionNull, PullDown>;
+type RxPinDefault = Pin<hal::gpio::bank0::Gpio1, FunctionNull, PullDown>;
+type EnabledUart = UartPeripheral<Enabled, hal::pac::UART0, (TxPin, RxPin)>;
+
+/// Initialise system clocks and PLLs from the external 12 MHz crystal.
+///
+/// # Arguments
+///
+/// * `xosc` - XOSC peripheral singleton.
+/// * `clocks` - CLOCKS peripheral singleton.
+/// * `pll_sys` - PLL_SYS peripheral singleton.
+/// * `pll_usb` - PLL_USB peripheral singleton.
+/// * `resets` - Mutable reference to the RESETS peripheral.
+/// * `watchdog` - Mutable reference to the watchdog timer.
+///
+/// # Returns
+///
+/// Configured clocks manager.
+///
+/// # Panics
+///
+/// Panics if clock initialisation fails.
+fn init_clocks(
+    xosc: hal::pac::XOSC,
+    clocks: hal::pac::CLOCKS,
+    pll_sys: hal::pac::PLL_SYS,
+    pll_usb: hal::pac::PLL_USB,
+    resets: &mut hal::pac::RESETS,
+    watchdog: &mut hal::Watchdog,
+) -> hal::clocks::ClocksManager {
+    hal::clocks::init_clocks_and_plls(
+        XTAL_FREQ_HZ, xosc, clocks, pll_sys, pll_usb, resets, watchdog,
+    )
+    .unwrap()
+}
+
+/// Unlock the GPIO bank and return the pin set.
+///
+/// # Arguments
+///
+/// * `io_bank0` - IO_BANK0 peripheral singleton.
+/// * `pads_bank0` - PADS_BANK0 peripheral singleton.
+/// * `sio` - SIO peripheral singleton.
+/// * `resets` - Mutable reference to the RESETS peripheral.
+///
+/// # Returns
+///
+/// GPIO pin set for the entire bank.
+fn init_pins(
+    io_bank0: hal::pac::IO_BANK0,
+    pads_bank0: hal::pac::PADS_BANK0,
+    sio: hal::pac::SIO,
+    resets: &mut hal::pac::RESETS,
+) -> hal::gpio::Pins {
+    let sio = hal::Sio::new(sio);
+    hal::gpio::Pins::new(io_bank0, pads_bank0, sio.gpio_bank0, resets)
+}
+
+/// Initialise UART0 for serial output (stdio equivalent).
+///
+/// Configures UART0 at the requested baud rate with 8N1 framing on
+/// GPIO 0 (TX) and GPIO 1 (RX).
+///
+/// # Arguments
+///
+/// * `uart0` - PAC UART0 peripheral singleton.
+/// * `tx_pin` - GPIO pin to use as UART0 TX (GPIO 0).
+/// * `rx_pin` - GPIO pin to use as UART0 RX (GPIO 1).
+/// * `resets` - Mutable reference to the RESETS peripheral.
+/// * `clocks` - Reference to the initialised clock configuration.
+///
+/// # Returns
+///
+/// Enabled UART0 peripheral ready for blocking writes.
+///
+/// # Panics
+///
+/// Panics if the HAL cannot achieve the requested baud rate.
+fn init_uart(
+    uart0: hal::pac::UART0,
+    tx_pin: TxPinDefault,
+    rx_pin: RxPinDefault,
+    resets: &mut hal::pac::RESETS,
+    clocks: &hal::clocks::ClocksManager,
+) -> EnabledUart {
+    let pins = (
+        tx_pin.reconfigure::<FunctionUart, PullNone>(),
+        rx_pin.reconfigure::<FunctionUart, PullNone>(),
+    );
+    let cfg = UartConfig::new(UART_BAUD.Hz(), DataBits::Eight, None, StopBits::One);
+    UartPeripheral::new(uart0, pins, resets)
+        .enable(cfg, clocks.peripheral_clock.freq())
+        .unwrap()
+}
+
+/// Create a blocking delay timer from the ARM SysTick peripheral.
+///
+/// # Arguments
+///
+/// * `clocks` - Reference to the initialised clock configuration.
+///
+/// # Returns
+///
+/// Blocking delay provider.
+///
+/// # Panics
+///
+/// Panics if the cortex-m core peripherals have already been taken.
+fn init_delay(clocks: &hal::clocks::ClocksManager) -> cortex_m::delay::Delay {
+    let core = cortex_m::Peripherals::take().unwrap();
+    cortex_m::delay::Delay::new(core.SYST, clocks.system_clock.freq().to_Hz())
+}
+
+/// Application entry point for the button debounce demo.
+///
+/// Initializes button and LED, then continuously polls button state
+/// and mirrors it to the LED with UART reporting on edge transitions.
+///
+/// # Returns
+///
+/// Does not return.
+#[entry]
+fn main() -> ! {
+    let mut pac = hal::pac::Peripherals::take().unwrap();
+    let clocks = init_clocks(
+        pac.XOSC, pac.CLOCKS, pac.PLL_SYS, pac.PLL_USB, &mut pac.RESETS,
+        &mut hal::Watchdog::new(pac.WATCHDOG),
+    );
+    let pins = init_pins(pac.IO_BANK0, pac.PADS_BANK0, pac.SIO, &mut pac.RESETS);
+    let uart = init_uart(pac.UART0, pins.gpio0, pins.gpio1, &mut pac.RESETS, &clocks);
+    let delay = RefCell::new(init_delay(&clocks));
+    let btn_pin = pins.gpio15.into_pull_up_input();
+    let led_pin = pins.gpio25.into_push_pull_output();
+    let mut btn = button::ButtonDriver::init(btn_pin, DEBOUNCE_MS, |ms| {
+        delay.borrow_mut().delay_ms(ms);
+    });
+    let mut led = button::ButtonLed::init(led_pin);
+    uart.write_full_blocking(b"Button driver initialized: button=GPIO15  led=GPIO25\r\n");
+    let mut last_state = false;
+    loop {
+        let pressed = btn.is_pressed();
+        led.set(pressed);
+        if pressed != last_state {
+            if pressed {
+                uart.write_full_blocking(b"Button: PRESSED\r\n");
+            } else {
+                uart.write_full_blocking(b"Button: RELEASED\r\n");
+            }
+            last_state = pressed;
+        }
+        delay.borrow_mut().delay_ms(POLL_MS);
+    }
+}
+
+#[unsafe(link_section = ".bi_entries")]
+#[used]
+pub static PICOTOOL_ENTRIES: [hal::binary_info::EntryAddr; 5] = [
+    hal::binary_info::rp_cargo_bin_name!(),
+    hal::binary_info::rp_cargo_version!(),
+    hal::binary_info::rp_program_description!(c"Button Debounce Demo"),
+    hal::binary_info::rp_cargo_homepage_url!(),
+    hal::binary_info::rp_program_build_attribute!(),
+];
+
+// End of file