//DO NOT use digital read on pins that are in port b
volatile unsigned char holdint = 0;
void setup() {
  Serial.begin(115200);
  pinMode(57, INPUT); //Kard 1 IO 0 CN 5
  pinMode(56, INPUT); //Kard 1 IO 1 CN 4
  pinMode(54, INPUT); //Kard 1 IO 3 CN 2
  pinMode(55, INPUT); //Kard 0 IO 3 CN 3
  //need direct register addressing CN pins not set up in MPIDE yet
  unsigned int value;
  AD1PCFGSET = 0x0000803c;     //turn analog 2-5,15 off
  AD1CON2CLR = 0x0000d000; //turn off external voltage compare pins?
  CNCON = 0x00008000;   //turn "interrupt on change" on
  CNEN = 0x0000003c;   //enable cn2-5
  CNPUE= 0x00000000; //weak pull up off
  value = PORTB;      //Read the Port
  IPC6SET = 0x001b0000; //set priority to 6 sub 4
  IFS1CLR = 0x0001; //clear the interupt flag bit
  IEC1SET= 0x0001; // Enable Change Notice interrupts
}
void loop() {
  if(holdint & 0x01)
  {
    holdint &= ~0x01;
    Serial.println("CN2 Interrupt");
  }
  if(holdint & 0x02)
  {
    holdint &= ~0x02;
    Serial.println("CN3 Interrupt");
  }
  if(holdint & 0x04)
  {
    holdint &= ~0x04;
    Serial.println("CN4 Interrupt");
  }
  if(holdint & 0x08)
  {
    holdint &= ~0x08;
    Serial.println("CN5 Interrupt");
  }
}
extern "C"
{

void __ISR(_CHANGE_NOTICE_VECTOR, ipl6) CN_Interrupt_ISR(void)
{
  unsigned int thisb = PORTB; // Read PORTB to clear mismatch condition
  unsigned int static lastb;
  if ((thisb & 0x01) != (lastb & 0x01) && (thisb & 0x01)) //cn2 fire going high
  {
    holdint |= 0x01;
  }
  if ((thisb & 0x02) != (lastb & 0x02) && !(thisb & 0x02)) //cn3 fire going low
  {
    holdint |= 0x02;
  }
  if ((thisb & 0x04) != (lastb & 0x04)) //cn4 fire on every change
  {
    holdint |= 0x04;
  }
  if ((thisb & 0x08) != (lastb & 0x08) && (thisb & 0x08)) //cn5 fire going high
  {
    holdint |= 0x08;
  }
  lastb = thisb;
  IFS1CLR = 0x0001; // Be sure to clear the CN interrupt status
                    // flag before exiting the service routine.
}
} // end extern "C"