DAC0832 simulating with Proteus and Arduino

void setup() {
 
   DDRD = 255;
}

void loop() {
 
  PORTD++;
  delay(100);
  if ( PORTD == 255){
    while ( PORTD != 0 ){
      PORTD--;
      delay(100);
      }
  }
}

int inc = 1;
void setup() {
   PORTD = 0;
   DDRD = 255;
}

void loop()
   {
    PORTD += inc;
    delay(100);
     if ( PORTD > 254 ) inc = -1;
     if ( PORTD < 1 ) inc = 1;
    }

int led[8] = {0,1,2,3,4,5,6,7};
boolean A[8];
int inc=1;
int saida=0;

void setup() {  
  for(int i=0;i<8;i++)  {   
    pinMode(led[i], OUTPUT);  
  }  
}

void loop() {  
  saida += inc;  
  if( saida > 254 )  {   
      inc= -1;  
    }  
  if( saida < 1 )  {   
      inc= 1;  
    }  
  conversor();  
 
  for(int i=0;i<8;i++)  {   
    digitalWrite(led[i],A[i]);  
  }  
}
void conversor(){
  int valor=saida;
  for(int i=0;i<8;i++)  {
      if(valor%2>0)    {
          A[i]=1;
        }
        else    {
          A[i]=0;
        }
      valor=(valor/2);
    }
  }