diff --git a/main.c b/main.c
index 649665b..f5e1b22 100644
--- a/main.c
+++ b/main.c
@@ -65,6 +65,9 @@ ISR(PORTA_PORT_vect)
  */
 int main(void)
 {
+    // MCU resumes execution here after reset
+    sleep_disable(); // Disable sleep
+
     // Configure LED pins as outputs
     VPORTA.DIR = (PA1_SET_MASK | PA2_SET_MASK | PA3_SET_MASK | PA6_SET_MASK | PA7_SET_MASK);
 
@@ -108,19 +111,17 @@ int main(void)
             blinkLed(true); // reset blink state machine
             leds_off();
 
+            _delay_ms(BUTTON_IGNORE_DURATION_MS * 2);
+
             // TODO: activate the interrupt for PA0
             PORTA.PIN0CTRL = PORT_PULLUPEN_bm | PORT_ISC_FALLING_gc;
 
-            sei(); // Enable global interrupts
-            while (1)
-            {
-                leds_off();
-                _delay_ms(BUTTON_IGNORE_DURATION_MS / 20);
-                leds_on();
-                _delay_ms(BUTTON_IGNORE_DURATION_MS / 20);
-            }
+            set_sleep_mode(SLEEP_MODE_STANDBY); // Deepest sleep mode (standby)
+            sleep_enable();                     // Enable sleep
 
-            // TODO: add a isr that disabled all leds and loops in while(1);
+            cli();       // Disable global interrupts
+            sei();       // Re-enable interrupts
+            sleep_cpu(); // MCU sleeps here
         }
         else
         {