Button Click & Hold (AVR)

gistfile1.c

#define BTN_DEBOUCE 20 //ms


ISR(INT0_vect) {
    uint16_t timer = 0;
    while(bit_is_clear(PIND, PD2)) { // button hold down
        timer++; // count how long button is pressed
        _delay_ms(1);
    }
    if(timer > BTN_DEBOUCE) { // software debouncing button
        if(timer < 500UL) {//unsigned long
            //single click
            printString("single click");
        } else {
            //button hold
            printString("hold down");
        }
    }
}

void initInterrupt0(void) {
    GIMSK |= (1 << INT0); // general interrupt mask register -> enable interrupt on INT0
    MCUCR &= ~(1 << ISC00); // trigger interrupt on falling edge
    MCUCR |= (1 << ISC01); // trigger interrupt on falling edge
    sei(); //  set interrupt enable bit
}

Did this solution work for you?
I am asking because I don't see the use case as you block all other operations as the user is pressing the button.
Have you considered doing it with a 1ms Timer that counts for how long the button is pressed?

Hi, this code is quite old and you are right, it's blocking CPU. Since the same interrupt routine is called both when you first press and then when you release the button you can know how much time is passed between the two (of course you need debouncing to be sure you are checking the right button state).

Hello. Never use delay function in ISR. It is really bad practice, that can cause hard to debug problems.