AVR Freaks

I'm sorry guys, I disturb you here with avr. I hope you have a good mood before winter holidays and I wish to all of you and your families be happy and healthy. let's don't forget as this is a magic time for our kids. My best wishes from Ukraine!

Ok. Here is my problem.

I can't wake up Tiny13 from "Power-down" sleep mode, but it awake if set "Idle Mode". I checking current consumption with my multimeter, Tiny13 goes to sleep successfully -  only 0,5 microA. If sleep mode disable it takes 1,2mA.

According to datasheet (table 7-1 on page 30) it should awake from INT0 interrupt source, which I need.

What am I doing wrong? Should I enable watchdog? (but I don't need to wake-up from it.) Thank you.

#define F_CPU 1200000UL 
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>

#define LED_ON			PORTB |= (1 << PB0)
#define LED_OFF			PORTB &=~(1 << PB0)
#define LED_TOG			PORTB ^= (1 << PB0)
#define BACKLIGHT		5000

void setup () {
	
	// *** Port Setup ***
	
	// PB1 - Button
	// 0 input
	
	// PB0 - LED
	// 1 output
	
	DDRB  = (0 << PB5) | (0 << PB4) | (0 << PB3) | (0 << PB2) | (0 << PB1) | (1 << PB0);
	PORTB = (1 << PB5) | (1 << PB4) | (1 << PB3) | (1 << PB2) | (1 << PB1) | (0 << PB0);
	
	// Analog Comparator Disable
	ACSR |= (1 << ACD);
	
	// *** Interrupts Setup ***
	
	// Enable External Interrupt on INT0
	GIMSK |= (1 << INT0);
	
	// The falling edge will generate an interrupt (H to L)
	MCUCR |= (1 << ISC01);
	
	// Enable Sleep Mode: Power-down
	set_sleep_mode(SLEEP_MODE_PWR_DOWN);

}

ISR (INT0_vect) {
	
	asm("nop");
	
} 

void go_to_sleep_mode () {
	
	//MCUCR |= (1 << SM1);
	//MCUCR |= (1 << SE);
	//asm("sleep");
	
	sleep_enable();
	sleep_cpu();
	
}

int main(void)
{

	setup();
	sei();
	
    while(1)
    {
        
		
		// Please sleep now
		go_to_sleep_mode();
		
		cli();
		
		LED_ON;
		_delay_ms(BACKLIGHT);
		LED_OFF;
		_delay_ms(BACKLIGHT);
		
		sei();
		
    
	}

}