ATTiny 13 wake up from sleep mode

Question

I'm trying to put my ATTiny into sleep mode and than wake it up. I use this code to put it to sleep:

void go_to_sleep(){
is_sleeping = true;
RED_HIGH;
YELLOW_HIGH;
GREEN_HIGH;
sleep_enable();
sei();
sleep_cpu();
sleep_disable();

}

Than I use external interrupt but nothing happens.

ISR(INT0_vect)
{
    if(is_sleeping){
        awake();
    }
    if(BUTTON_LOW){ // przycisk wciśnięty?
        _delay_ms(80);
        if(BUTTON_LOW){ // nadal wciśnięty?
            do_thing();
        }
    }
}
void awake(){
    is_sleeping = false;
    RED_LOW;
    YELLOW_HIGH;
    GREEN_HIGH;
}

Any ideas welcomed.

I add main to show that interrupt works fine, I've tested it without sleep mode:

int main(void)
{
MCUCR |= 1<<SE; // zezwolenie na sleep mode
GIMSK |= 1<<INT0; // int0 enable
MCUCR |= 0<<ISC00 | 1<<ISC01; //przerwanie zboczem opadającym
sei(); // zezwolenie na przerwania

//OUTPUTS
DDRB |= RED | YELLOW  | GREEN;
//INPUTS
DDRB &= ~BUTTON;
// Podciągnięcie przycisku do VCC
PORTB |= BUTTON;

set_sleep_mode(SLEEP_MODE_PWR_DOWN); // ustaw tryb sleep modu, ta linijka nie uruchamia go

//Stan początkowy
RED_LOW;
YELLOW_HIGH;
GREEN_HIGH;

timer0(TIMER_PRESCALER_1024,255);

while(1);
}

Answer 1

You must enable the INT0 interrupt in the General Interrupt Mask Register....

Add the line...

GIMSK |= _BV( PCIE );

...before you go to sleep and activating the INT0 pin (by default having a low level) should wake the MCU from sleep.

Note that with your code as shown, I'm not sure that you would be able to tell that the CPU had woken up. Try having an output on a pin for high just before you sleep, and then have it go low when you wake so you will know it happened.

Answer 2

I believe you cross-posted your issue with waking up from power-down mode. Verify if my answer to the other question works for you here, ie that you cannot wake from power-down using falling edge detection on INT0 because of absence of I/O clock when powered-down.