//======================================
//=====PCINT(Pin Change Interrupt)=====
//======================================
int count = 0, val=0;
volatile uint8_t portbhistory = 0xFF;
void setup() {
portbhistory = PINB;  // read PINB bits at power_up
Serial.begin(19200);
 pinMode(8, INPUT);
 pinMode(13, OUTPUT);
 PCICR = B00000001;
 PCMSK0 = B00000001;
  Serial.print("PINB ");  //debug
  Serial.println(portbhistory);
}
ISR(PCINT0_vect){

  uint8_t changedbits, risingbits, fallingbits, portbnow;
  portbnow = PINB;
  changedbits = portbnow ^ portbhistory;
  risingbits = portbnow & ~portbhistory;
  fallingbits = ~portbnow & portbhistory;
  portbhistory = portbnow;

  val = digitalRead(8);
  //digitalWrite(13, val);
  Serial.print("interrupt ");
  Serial.println(++count);
   Serial.print("changebits ");
  Serial.println(changedbits, HEX);
  

  if (fallingbits & (1 << PB0)) {  // Falling Edge on PCINT10 - PB2
       Serial.println("falling");     // Pin is Low, so cable is connected
  }
  if (risingbits & (1 << PB0)) {   // Rising Edge on PCINT10 - PB2
     Serial.println("rising");         // Pin is High, so cable is disconnected
  }
}
void loop() {
  // put your main code here, to run repeatedly:
//  val = digitalRead(8);
//  digitalWrite(13, val);
  delay(2000);
}