Tweak a little bit

src/display.rs

@@ -35,7 +35,7 @@ impl Rgb565 {
         Rgb565(255, 255, 0)
     }
 
-    pub fn purple() -> Rgb565 {
+    pub fn magenta() -> Rgb565 {
         Rgb565(255, 0, 255)
     }
 

src/main.rs

@@ -6,17 +6,22 @@
 
 use atmega_hal::{
     Adc, Usart,
+    port::{Pin, mode},
     spi::{self, Settings},
     usart::Baudrate,
 };
 use embedded_hal::delay::DelayNs;
 use panic_halt as _;
 
-use crate::display::{Display, Position, Rgb565};
+use crate::{
+    display::{Display, Position, Rgb565},
+    peripherals::{Button, Knob},
+};
 
 mod display;
 mod font;
 mod image;
+mod peripherals;
 
 type CoreClock = atmega_hal::clock::MHz8;
 
@@ -64,25 +69,40 @@ fn main() -> ! {
 
     let mut adc: Adc<CoreClock> = atmega_hal::Adc::new(dp.ADC, Default::default());
 
-    let button = pins.pd5.into_pull_up_input();
-    let potentiometer = pins.pc1.into_analog_input(&mut adc);
+    let mut button = Button::from(pins.pd5.into_pull_up_input());
+    let mut knob = Knob {
+        pin: pins.pc1.into_analog_input(&mut adc),
+        adc,
+    };
 
-    let colors = [Rgb565::red(), Rgb565::green(), Rgb565::blue()];
+    let colors = [
+        Rgb565::red(),
+        Rgb565::green(),
+        Rgb565::blue(),
+        Rgb565::cyan(),
+        Rgb565::magenta(),
+        Rgb565::yellow(),
+    ];
     let mut idx = 0;
 
     let mut delay = atmega_hal::delay::Delay::<CoreClock>::new();
-    loop {
-        let raw_input = potentiometer.analog_read(&mut adc);
-        let input = raw_input as f32 / 1024f32;
 
-        display.draw_rect(
-            Position { x: 0, y: 0 },
-            Position { x: 200, y: 200 },
-            (colors[idx] * input).as_color(),
-        );
-        if button.is_low() {
+    let mut last_input = 0f32;
+    loop {
+        let input = knob.poll();
+        let button_poll = button.poll();
+
+        if button_poll {
             idx = (idx + 1) % colors.len();
         }
-        delay.delay_ms(1000);
+
+        if last_input != input || button_poll {
+            last_input = input;
+            display.draw_rect(
+                Position { x: 0, y: 0 },
+                Position { x: 200, y: 200 },
+                (colors[idx] * input).as_color(),
+            );
+        }
     }
 }

src/peripherals.rs

@@ -0,0 +1,57 @@
+use atmega_hal::{
+    Adc, Atmega,
+    adc::{AdcChannel, AdcOps},
+    pac::ADC,
+    port::{
+        Pin, PinOps,
+        mode::{self, PullUp},
+    },
+};
+
+use crate::CoreClock;
+
+pub struct Button<T: PinOps> {
+    pin: Pin<mode::Input<PullUp>, T>,
+    was_pressed: bool,
+    pub is_pressed: bool,
+}
+
+impl<T: PinOps> Button<T> {
+    pub fn from(pin: Pin<mode::Input<PullUp>, T>) -> Button<T> {
+        Button {
+            pin,
+            is_pressed: false,
+            was_pressed: false,
+        }
+    }
+
+    pub fn poll(&mut self) -> bool {
+        self.is_pressed = self.pin.is_low();
+        if self.is_pressed {
+            if !self.was_pressed {
+                self.was_pressed = true;
+                true
+            } else {
+                false
+            }
+        } else {
+            self.was_pressed = false;
+            false
+        }
+    }
+}
+
+pub struct Knob<T: PinOps> {
+    pub pin: Pin<mode::Analog, T>,
+    pub adc: Adc<CoreClock>,
+}
+
+impl<T: PinOps> Knob<T>
+where
+    Pin<mode::Analog, T>: AdcChannel<Atmega, ADC>,
+{
+    pub fn poll(&mut self) -> f32 {
+        let read = self.pin.analog_read(&mut self.adc);
+        read as f32 / 1024f32
+    }
+}