// PCINT0  on pins 53 52 51 50 10 11 12 13 ( PORT B)
// PCINT2  A8 ... A15 (PORT K)

const uint8_t portBPins[] = {53, 52, 51, 50, 10, 11, 12, 13};
const uint8_t portKPins[] = {A15, A14, A13, A12, A11, A10, A9, A8};

enum ActionType : uint8_t {NONE, ACTION_PORTB, ACTION_PORTK};
volatile ActionType action = NONE;
volatile uint8_t portState;

ActionType actionCopy;
uint8_t portStateCopy;

void activatePCINT(uint8_t aPin)
{
  *digitalPinToPCMSK(aPin) |= bit (digitalPinToPCMSKbit(aPin));  // enable it
  PCIFR  |= bit (digitalPinToPCICRbit(aPin)); // clear interrupt flag
  PCICR  |= bit (digitalPinToPCICRbit(aPin)); // enable interrupt
}

ISR (PCINT0_vect) {
  action = ACTION_PORTB;
  portState = PINB;
}

ISR (PCINT2_vect) {
  action = ACTION_PORTK;
  portState = PINK;
}

void printAction() {
  for (int8_t i = 7; i >= 0; i--) Serial.write(bitRead(portStateCopy, i) == 0 ? '-' : '*');
  Serial.println(actionCopy == ACTION_PORTB ? F("\tPB ") : F("\tPK "));
}

void setup() {

  for (uint8_t aPin : portBPins) {
    pinMode( aPin, INPUT_PULLUP);
    activatePCINT(aPin);
  }

  for (uint8_t aPin : portKPins) {
    pinMode( aPin, INPUT_PULLUP);
    activatePCINT(aPin);
  }

  Serial.begin(115200);
  Serial.println(F("Ready"));
}

void loop() {
  switch (action) {
    case NONE:
      break;

    case ACTION_PORTB:
    case ACTION_PORTK:
      // critical section
      noInterrupts();
      actionCopy = action;
      portStateCopy = portState;
      action = NONE;
      interrupts();
      printAction();
      break;
  }
}