//display 0 to 9 and  9 to 0 with delay
#define DELAY 1000000

void setup() 
{
volatile char* dir1;
dir1 = 0x30;
*dir1 = 0xff;

}

void loop() 
{
  volatile char* data1;
  data1 = 0x31;
  volatile char prime =1;
  volatile long i,j,k;
   volatile int arr[] = {0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f};
  {
    for(j=0;j<9;j++)
    {
      volatile char x=37;
      j=x/10;
      *data1 = arr[j];
      for(i=0;i<DELAY;i++);
    }
  }
}