Initial commit

src/bin/06_button_events.rs

@@ -0,0 +1,111 @@
+// Button events.
+// Turn the 5-way button into robot meaning.
+// Keep raw input separate from behaviour.
+
+#![deny(unsafe_code)]
+#![no_std]
+#![no_main]
+
+use cortex_m_rt::entry;
+use panic_probe as _;
+use stm32f1xx_hal::{pac, prelude::*};
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum ButtonDirection {
+    None,
+    Center,
+    Up,
+    Down,
+    Left,
+    Right,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+enum RobotEvent {
+    NoEvent,
+    StartStop,
+    BallLeft,
+    BallRight,
+    BallCentered,
+    ObstacleDetected,
+}
+
+/// Turn raw button states into one direction.
+fn read_direction(center: bool, up: bool, down: bool, left: bool, right: bool) -> ButtonDirection {
+    if center {
+        ButtonDirection::Center
+    } else if up {
+        ButtonDirection::Up
+    } else if down {
+        ButtonDirection::Down
+    } else if left {
+        ButtonDirection::Left
+    } else if right {
+        ButtonDirection::Right
+    } else {
+        ButtonDirection::None
+    }
+    // Q: Why not match?
+}
+
+/// Turn one button direction into one robot event.
+fn direction_to_event(direction: ButtonDirection) -> RobotEvent {
+    match direction {
+        ButtonDirection::None => RobotEvent::NoEvent,
+        ButtonDirection::Center => RobotEvent::StartStop,
+        ButtonDirection::Left => RobotEvent::BallLeft,
+        ButtonDirection::Right => RobotEvent::BallRight,
+        ButtonDirection::Up => RobotEvent::BallCentered,
+        ButtonDirection::Down => RobotEvent::ObstacleDetected,
+    }
+}
+
+#[entry]
+fn main() -> ! {
+    let dp = pac::Peripherals::take().unwrap();
+    let cp = cortex_m::Peripherals::take().unwrap();
+
+    let mut rcc = dp.RCC.constrain();
+    let mut gpioa = dp.GPIOA.split(&mut rcc);
+    let mut gpiob = dp.GPIOB.split(&mut rcc);
+    let mut gpioc = dp.GPIOC.split(&mut rcc);
+    let mut delay = cp.SYST.delay(&rcc.clocks);
+
+    let center = gpioa.pa8.into_pull_down_input(&mut gpioa.crh);
+    let up = gpioa.pa9.into_pull_down_input(&mut gpioa.crh);
+    let mut vcc = gpioa.pa10.into_push_pull_output(&mut gpioa.crh);
+    let right = gpiob.pb13.into_pull_down_input(&mut gpiob.crh);
+    let down = gpiob.pb14.into_pull_down_input(&mut gpiob.crh);
+    let left = gpiob.pb15.into_pull_down_input(&mut gpiob.crh);
+    let mut gnd = gpiob.pb12.into_push_pull_output(&mut gpiob.crh);
+    let mut led = gpioc.pc13.into_push_pull_output(&mut gpioc.crh);
+
+    vcc.set_high();
+    gnd.set_low();
+    led.set_high();
+
+    let mut last_event = RobotEvent::NoEvent;
+
+    loop {
+        let direction = read_direction(
+            center.is_high(),
+            up.is_high(),
+            down.is_high(),
+            left.is_high(),
+            right.is_high(),
+        );
+        let event = direction_to_event(direction);
+
+        if event != last_event {
+            last_event = event;
+
+            if event == RobotEvent::NoEvent {
+                led.set_high();
+            } else {
+                led.set_low();
+            }
+        }
+
+        delay.delay_ms(25u32);
+    }
+}