Interrupts_TwoSwitchesOnSamePort.ino

/* Investigates interrupts from two switches
 * In this case, both switches connect to the same port
 * There is a switch at PC4 and PC5
 * 12/6/2015
*/

/*----------------------------Global Variables-----------------------------*/
volatile boolean foundInterrupt;
volatile byte data;
byte datamask = 0b00110000;  // Switches on PC4 and PC5

/*-----------------------------Interrupt Service Routine----------------*/
ISR (PCINT1_vect){  //Exactly like this for interrupts on PC0 - PC5

  data = PINC & datamask;
  PCMSK1 = 0;  //Disables the interrupt to avoid further interrupts
  //Avoids the interrupt when swich is closed again
  
  foundInterrupt = true; //Lets other functions know that interrupt occured
}


/*___________________________________SetUp__________________________________*/  
void setup() {
  Serial.begin(9600);

  DDRC = 0;  //PC0 - PC5 are inputs
  PORTC = 0b00110000;  // Enable Pull-up resistors for switchs at PC4 and PC5
  
  
  //Setup Interrupt
  PCICR = 0b00000010;  //Enables interrupts for PC0 - PC5
  PCMSK1 = 0b00110000; //further refines interrupt selection to PC4 and PC5

  foundInterrupt = false; 

  while(1){
    delay(2000);
    Serial.println("Checking For Interrupt");
    if (foundInterrupt){  //If either switch is pressed ISR will set this true
      if (data ==  0b00010000){
        Serial.println("\tRed Switch Pressed");
      }
      else if (data == 0b00100000){
        Serial.println("\tGreen Switch Pressed");
      }
    }
    foundInterrupt = false;  //This is made true in ISR when interrupts occur
    data = PINC & datamask;
    if (data == 0b00110000){
      PCMSK1 = 0b00110000;  //Enables interrupts again.  Disabled in ISR
    }
  }

}

void loop() {
  // put your main code here, to run repeatedly:

}