examples: uno: Add watchdog example

examples/arduino-uno/src/bin/uno-watchdog.rs

@@ -0,0 +1,29 @@
+#![no_std]
+#![no_main]
+
+use arduino_hal::prelude::*;
+use panic_halt as _;
+use arduino_hal::hal::wdt;
+
+#[arduino_hal::entry]
+fn main() -> ! {
+    let dp = arduino_hal::Peripherals::take().unwrap();
+    let pins = arduino_hal::pins!(dp);
+
+    let mut led = pins.d13.into_output();
+    led.set_high();
+
+    for i in 0..20 {
+        led.toggle();
+        arduino_hal::delay_ms(100);
+    }
+
+    let mut watchdog = wdt::Wdt::new(dp.WDT, &dp.CPU.mcusr);
+    watchdog.start(wdt::Timeout::Ms2000).unwrap();
+
+    loop {
+        led.toggle();
+        arduino_hal::delay_ms(1000);
+        watchdog.feed();
+    }
+}