mega.c

while (1)
{
  switch (PINB) {
    case 0b11111110 : {
      x=0b10000000;
      for (i=0 ; i<7 ; i++ ) { 
        PORTA=x;
        delay_ms(100);
        x=x>>1;
      }
      break;
    }
  }    
};