diff --git a/src/clockinator.S b/src/clockinator.S
index 54fa04e..7bad95c 100644
--- a/src/clockinator.S
+++ b/src/clockinator.S
@@ -9,7 +9,7 @@
 .org 0x0000                 ; RESET Vector
     rjmp    main
 .org 0x0002                 ; INT0 button interrupt (tap tempo)
-    ;rjump tap_tempo --> should have timer0_start --> if timer0_overflow_count=0 start timer (?)
+    rjmp    tap_tempo_isr
 .org 0x0004                 ; TIMER0 overflow
     rjmp    timer0_isr
 .org 0x0006                 ; TIMER1_COMPA
@@ -44,6 +44,11 @@ main:
     cbi         DDRB,       PB2         ; Set EC11 button (555 square wave) on PB2 as input
     sbi         PORTB,      PB2         ; Enable pull-up on PB2
 
+    ldi     r16,    (1<<ISC01) | (0<<ISC00)
+    out     MCUCR,  r16                     ; ISC01=1, ISC00=0 → falling edge
+    ldi     r16,    (1<<INT0)
+    out     GIMSK,  r16                     ; Enable external interrupt INT0
+
     ;ldi         r26,        60          ; Default BPM //TODO: save to eeprom not register, on runtime also ldi on r24 register
 
     ; Setup general registers and global variables