add doc comment for wiring, refactor for loops

Rahix · May 5, 2024 · 44038a2 · 44038a2
1 parent e6a0b52
commit 44038a2
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diff --git a/examples/arduino-mega2560/src/bin/mega2560-i2cdetect.rs b/examples/arduino-mega2560/src/bin/mega2560-i2cdetect.rs
@@ -18,9 +18,11 @@ fn main() -> ! {
     );
 
     ufmt::uwriteln!(&mut serial, "Write direction test:\r").unwrap_infallible();
-    i2c.i2cdetect(&mut serial, arduino_hal::i2c::Direction::Write).unwrap_infallible();
+    i2c.i2cdetect(&mut serial, arduino_hal::i2c::Direction::Write)
+        .unwrap_infallible();
     ufmt::uwriteln!(&mut serial, "\r\nRead direction test:\r").unwrap_infallible();
-    i2c.i2cdetect(&mut serial, arduino_hal::i2c::Direction::Read).unwrap_infallible();
+    i2c.i2cdetect(&mut serial, arduino_hal::i2c::Direction::Read)
+        .unwrap_infallible();
 
     loop {}
 }
diff --git a/examples/arduino-mega2560/src/bin/mega2560-rgb-led.rs b/examples/arduino-mega2560/src/bin/mega2560-rgb-led.rs
@@ -2,66 +2,60 @@
 #![no_main]
 
 use panic_halt as _;
-
 use arduino_hal::simple_pwm::IntoPwmPin;
 use arduino_hal::simple_pwm::Prescaler;
 use arduino_hal::simple_pwm::{Timer3Pwm, Timer4Pwm};
 
+/// This example demonstrates how to fade an RGB LED connected to an Arduino board.
+///
+/// Wiring:
+/// - Connect the common cathode of the RGB LED to GND.
+/// - Connect the red LED anode to pin D6 through a current-limiting resistor.
+/// - Connect the green LED anode to pin D5 through a current-limiting resistor.
+/// - Connect the blue LED anode to pin D3 through a current-limiting resistor.
+///
+/// Note: The current-limiting resistor values depend on the specific RGB LED and the desired brightness.
+///       Typically, a resistor value between 220Ω and 1kΩ is suitable.
+
 #[arduino_hal::entry]
 fn main() -> ! {
     let dp = arduino_hal::Peripherals::take().unwrap();
     let pins = arduino_hal::pins!(dp);
 
     let timer0 = Timer4Pwm::new(dp.TC4, Prescaler::Prescale64);
     let timer1 = Timer3Pwm::new(dp.TC3, Prescaler::Prescale64);
+
     let mut d6 = pins.d6.into_output().into_pwm(&timer0);
     let mut d5 = pins.d5.into_output().into_pwm(&timer1);
     let mut d3 = pins.d3.into_output().into_pwm(&timer1);
 
     let max_duty_d6 = d6.get_max_duty();
     let max_duty_d5 = d5.get_max_duty();
     let max_duty_d3 = d3.get_max_duty();
+
     let delay_time = 10;
 
     d6.enable();
     d5.enable();
     d3.enable();
 
     loop {
-        // Fade in red
-        for i in 0..=max_duty_d6 {
-            d6.set_duty(i);
-            arduino_hal::delay_ms(delay_time);
-        }
-
-        // Fade out red
-        for i in (0..=max_duty_d6).rev() {
+        // Fade in/out red
+        for i in (0..=max_duty_d6).chain((0..=max_duty_d6 - 1).rev()) {
             d6.set_duty(i);
             arduino_hal::delay_ms(delay_time);
         }
 
-        // Fade in green
-        for i in 0..max_duty_d5 {
+        // Fade in/out green
+        for i in (0..=max_duty_d5).chain((0..=max_duty_d5 - 1).rev()) {
             d5.set_duty(i);
-            arduino_hal::delay_ms(delay_time)
-        }
-
-        // Fade out green
-        for i in (0..max_duty_d5).rev() {
-            d5.set_duty(i);
-            arduino_hal::delay_ms(delay_time)
-        }
-
-        // Fade in blue
-        for i in 0..max_duty_d3 {
-            d3.set_duty(i);
-            arduino_hal::delay_ms(delay_time)
+            arduino_hal::delay_ms(delay_time);
         }
 
-        // Fade out blue
-        for i in (0..max_duty_d3).rev() {
+        // Fade in/out blue
+        for i in (0..=max_duty_d3).chain((0..=max_duty_d3 - 1).rev()) {
             d3.set_duty(i);
-            arduino_hal::delay_ms(delay_time)
+            arduino_hal::delay_ms(delay_time);
         }
     }
-}
+}