/************************************************************* 
 Program: Pin Change Interrupt Test
 Coder: Jackie
 Purpose: 
*************************************************************/
#define rLED 6  //PH3 0000 1000 0x08
#define gLED 5  //PE3 0000 1000 0x08
#define SW1 14  //PJ1 0000 0010 0x02 PCINT 10
//PCICR |= 0x01 - bit1(PCIE1) enabled to actavate PCINT[15:8]
//PCMSK2 |= 0x04 - bit3(PCINT10) enabled
//PCIFR(flag register) any logic change on PCINT10 will set bit1(PCIF1) and execute ISR
//PCIFR resets to zero after ISR is executed


void setup() {
  Serial.begin(9600);
  pinMode(rLED,OUTPUT);
  pinMode(gLED,OUTPUT);
  pinMode(SW1,INPUT_PULLUP);

  //PCI Enable falls under PCICR(PCI Control Register)
  
  //PCIE[2:0] - the num is the bit value - only uses bit0:2
  //bit2 enables PCINT 23:16 - PCI2 Interrupt Vector
  //bit1 enables PCINT 15:8  - PCI1 Interrupt Vector
  //bit0 enables PCINT 7:0   - PCI0 Interrupt Vector

  
  //the wanted PCINT pin is enabled individual using PCMSK(PC Mask) register
  //PCMSK2 has PCINT[23:16] and corresponds to bit 7:0 of PCMSK2
  //PCMSK[1:0] is similar
  //enable on pin set, clear to disable


  //PCIFR - PCI Flag Registory - 
  //unlike external interrupts, PCI doesn't have ISCn[1:0] to set the edge type
  //a bit more complicated way of setting rising/falling/dual edge interrupt request
  //any logic changes on PCINT[23:16](PCIE2) pins will trigger an interrupt request and PCIF2 becomes set
  //it will then execute the ISR(PCINTn_vect) and the flag bit will be cleared
  //flag bit can be cleared by writing a 1 to PCIFn 

  cli();

    PCICR |= 0x02;   //bit1(PCIE1) enabled to actavate PCINT[15:8]
    PCMSK1 |= 0x04;  //bit2(PCINT10) enabled

  sei();
} //void setup end


void loop() {
  PINE |= 0x08;
  Serial.println("DELAY START");
  delay(1000);
  Serial.println("DELAY END\n------------");
} //void loop end


//ISR vector# uses same number as PCICR(PCIE#)
ISR(PCINT1_vect) {
  cli();
    if (!(digitalRead(SW1))) {    //toggle LED on falling edge only (logic 0)
      if (PINH & 0x08) digitalWrite(rLED,LOW);
      else digitalWrite(rLED,HIGH);
    }
  sei();
} //ISR(PCINT10_vect) end