8255.ino

const int a0=9;
const int a1=10;
const int WR=11;
const int RD=12;

void setup()
{
  pinMode(0,OUTPUT);
  pinMode(1,OUTPUT);
  pinMode(2,OUTPUT);
  pinMode(3,OUTPUT);
  pinMode(4,OUTPUT);
  pinMode(5,OUTPUT);
  pinMode(6,OUTPUT);
  pinMode(7,OUTPUT);
  pinMode(a0,OUTPUT);
  pinMode(a1,OUTPUT); 
  pinMode(WR,OUTPUT);
  pinMode(RD,OUTPUT);
}

void loop(){
  digitalWrite(RD,1);    //Disabling READ
  digitalWrite(WR,1);   //Disabling WRITE

  digitalWrite(a0,1);   //Selecting Control Register
  digitalWrite(a1,1);   //Selecting Control Register
  digitalWrite(7,1);   //
  digitalWrite(6,0);   //
  digitalWrite(5,0);   //
  digitalWrite(4,0);   // 8255 All Ports as OUTPUT
  digitalWrite(3,0);   //
  digitalWrite(2,0);   //
  digitalWrite(1,0);   //
  digitalWrite(0,0);   //
  digitalWrite(WR,0);    //Enabling WRITE

  led_on(1,0,0,0,0,0,0,0);
  led_on(0,1,0,0,0,0,0,0);
  led_on(0,0,1,0,0,0,0,0);
  led_on(0,0,0,1,0,0,0,0);
  led_on(0,0,0,0,1,0,0,0);
  led_on(0,0,0,0,0,1,0,0);
  led_on(0,0,0,0,0,0,1,0);
  led_on(0,0,0,0,0,0,0,1);
  led_on(0,0,0,0,0,0,0,0);
  
  led_on(0,1,1,1,1,1,1,1);
  led_on(1,0,1,1,1,1,1,1);
  led_on(1,1,0,1,1,1,1,1);
  led_on(1,1,1,0,1,1,1,1);
  led_on(1,1,1,1,0,1,1,1);
  led_on(1,1,1,1,1,0,1,1);
  led_on(1,1,1,1,1,1,0,1);
  led_on(1,1,1,1,1,1,1,0);
  led_on(1,1,1,1,1,1,1,1);
  
  delay(1000);
  digitalWrite(WR,1);   //Deselecting WRITE


}

void led_on(int d0,int d1,int d2,int d3,int d4,int d5,int d6,int d7){
  delay(500);
  digitalWrite(WR,1);   //WRITE Disabled
  digitalWrite(a0,1);   //Selecting Control Register
  digitalWrite(a1,0);   //Selecting Control Register
  digitalWrite(0,d0);    //
  digitalWrite(1,d1);    //
  digitalWrite(2,d2);    //
  digitalWrite(3,d3);    //
  digitalWrite(4,d4);    //Port-B all pins LOW
  digitalWrite(5,d5);    //
  digitalWrite(6,d6);    //
  digitalWrite(7,d7);    //
  digitalWrite(WR,0);   //WRITE Enabled
  delay(500);
}