//Initilaize the setpoint
int volatile setpoint;     //the set point is volatile because we are changing within interupts

//Minimum time between button hits in milliseconds
double debouncetime = 100; //increase if output flickers
//Time at which a button was last hit
double buttonhittime = 0;



void setup() {
//Set up the buttons to run the interupt code
//Refer to the online list to see which interupts you can connect your buttons to
//In this case the button outputs are on digital pins 2 and 3
attachInterrupt(0, incrementSetPoint, FALLING);
attachInterrupt(1, decrementSetPoint, FALLING);

//whatver other setup code goes here

}

void loop() {
//your code goes here

}

void incrementSetPoint() {
  if ((millis()- buttonhittime) > debouncetime) {
    setpoint = setpoint + 1;
    buttonhittime = millis();
  } 
}

void decrementSetPoint(){
  if ((millis()- buttonhittime) > debouncetime) {
    setpoint = setpoint - 1;
    buttonhittime = millis();
  } 
}