Example 3-2

// Example 3.2 – interrupts
 
#include <LiquidCrystal.h> // we need this library for the LCD commands
 
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
 
float noisy = 0;
 
void setup()
{
  lcd.begin(16, 2);             // need to specify how many columns and rows are in the LCD unit
  lcd.setCursor(0,0);
  lcd.println('* example 3.2 * ');
  lcd.setCursor(0,1);
  lcd.println('tronixstuff.com ');
  lcd.setCursor(0,1);
  delay(4000);
  lcd.clear();
  randomSeed(analogRead(0)); // reseed the random number generator with some noise
  attachInterrupt(0, panicone, RISING); // so when interrupt zero (digital pin 2) changes state, it will trigger the interrupt and go to function 'panicone'
  attachInterrupt(1, panictwo, RISING); // so when interrupt one (digital pin 3) changes state, it will trigger the interrupt and go to function 'panictwo'
}
 
void loop()
{
  noisy=random(1000);
  lcd.setCursor(0,0);
  lcd.print('Random Numbers!');
  lcd.setCursor(0,1);
  lcd.print('Number: ');
  lcd.print(noisy,0);
  delay(1000);
}
 
void panicone()
{
  lcd.clear();
  lcd.println('Interrupt one   ');
}
 
void panictwo()
{
  lcd.clear();
  lcd.println('Interrupt two   ');
}