char code_x[] = {0x81,0x42,0x24,0x18,0x18,0x24,0x42,0x81};
void setup() {
  char *row_port_dir  = (char *)0x10A;
  char *col_port_dir  = (char *)0x30;
  *row_port_dir = 0xFF;
  *col_port_dir = 0xFF;

  volatile char *row_port_out = (char *)0x10B; 
  volatile char *col_port_out = (char *)0x31; 


  while(1)
  {
    for(char i = 0;i < 8;i++)
    {
       *row_port_out = ~(1 << i);
       *col_port_out = code_x[i];
       *col_port_out = 0x00;
      //  delay(200);
    }
  }
}

void loop() {
  
}