How to enable Input pull-up on multiple pins (non-async-interrupt ones) that could trigger an ISR

[dattasaurabh82]

Target uC: ATTINY1607

Context:

Depending on which pins have Async Interrupt, an event on those pins can trigger an ISR, waking up the uC if it was sleeping.
So for 1607, have 4 such pins: PA2, PB2, PB6 & PC2.
I'm currently using PC2 in input pull up mode to trigger an ISR.

PORTC.PIN2CTRL = 0b00001001; // in INPUT pullup mode - will trigger an async ISR // for wakeup from sleep

The ISR itself is like this:

ISR(PORTC_PORT_vect) {
    byte flags = PORTC.INTFLAGS;
    PORTC.INTFLAGS = flags; //clear flags
    triggered = 1;
}

And in the main loop, I'm doing something like:

if (triggered == 1) {
    triggered = 0;
    S1 = PORTC.IN & PIN2_bm;
    if(S1){
      // do something ... 
    }
}

Unclear:

Now I want to add another button (Input pull) with the intention that it can also trigger the/an ISR.
I can't use the remaining Async Interrupt pins (i.e: PA2, PB2, PB6 which could to trigger ISR) as they are taken .
So I was thinking of using PC0, as it is still on the same port PORTC.
I tried using pinConfig() on PC0 like below

// thinking this will set the pin in INPUT PULLUP that can trigger an async interrupt
pinConfigure(PIN_PC0,(PIN_DIR_INPUT | PIN_PULLUP_ON | PIN_ISC_ENABLE));

If it triggers, the it should fire the same ISR as above.

ISR(PORTC_PORT_vect) {
    byte flags = PORTC.INTFLAGS;
    PORTC.INTFLAGS = flags; //clear flags
    triggered = 1;
    triggerTwo = 1; // added an extra var for another button
}

And in the main loop, I could imagine to do something like:

if (triggered == 1) {
    triggered = 0;
    S1 = PORTC.IN & PIN2_bm;
    if(S1){
      // do something ... 
    }
}

if (triggeredTwo == 1) {
    triggeredTwo = 0;
    S2= PORTC.IN & PIN0_bm;
    if(S2){
      // do something ... 
    }
}

But it doesn't trigger!
Is it a lost cause or there is still some ray of hope and what would be the cost? 🤔