diff --git a/Cargo.toml b/Cargo.toml
index 6fe10d1..35a8ada 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ cortex-m = "0.6.0"
 cortex-m-rt = "0.6.10"
 cortex-m-semihosting = "0.3.3"
 panic-halt = "0.2.0"
-metro_m0 = "0.6.0"
+metro_m0 = { version = "0.6.0", features = ["default", "unproven"] }
 
 # Uncomment for the panic example.
 # panic-itm = "0.4.1"
diff --git a/src/main.rs b/src/main.rs
index 27b8625..61a012b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -27,10 +27,16 @@ fn main() -> ! {
     );
     let mut pins = hal::Pins::new(peripherals.PORT);
     let mut red_led = pins.d13.into_push_pull_output(&mut pins.port);
+    let switch = pins.d3.into_pull_down_input(&mut pins.port);
 
     let mut delay = Delay::new(core.SYST, &mut clocks);
+
     loop {
-        delay.delay_ms(1000u16);
-        red_led.toggle();
+        // delay.delay_ms(255u8);
+        if switch.is_high().unwrap() {
+            red_led.set_high().unwrap();
+        } else {
+            red_led.set_low().unwrap();
+        }
     }
 }