diff --git a/src/main.rs b/src/main.rs
index 8ea7370..d58ee28 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -15,9 +15,9 @@ pub extern "C" fn main() -> ! {
     unsafe { write_volatile(DDRB, 0b11111111) };
 
     loop {
-        unsafe { write_volatile(PORTB, 0b00000000) };
-        sleep(1);
-        unsafe { write_volatile(PORTB, 0b00100000) };
+        let mut portb_value = unsafe { read_volatile(PORTB) };
+        portb_value = portb_value ^ (1 << 5);
+        unsafe { write_volatile(PORTB, portb_value) };
         sleep(1);
     }
 }