/*
NOOB CODE
void setup() {
  // put your setup code here, to run once:
  char *portf_dir;
  //This can work depending on the compiler and its settings. 
  //However, it’s not strictly standards-compliant because the address should be explicitly cast to a pointer type.
  portf_dir = 0x30; //better to write (char *)0x30;
  *portf_dir = 0xFF;

}

void loop() {
  //The volatile keyword ensures that each access to portf_data actually reads from or writes to the hardware register, preventing the compiler from optimizing away these accesses.
  volatile char *portf_data; //without volatile the LED will not glow because 
  // the compiler optimizes the value of *portf_dir and then it does not change to FF.
  portf_data = 0x31;
  *portf_data = 0x01;
}
*/
//BETTER CODE
#include "function.h"

void setup() {
  // put your setup code here, to run once:
  init_port();
}

void loop() {
  //1. led on
  char x;
  x = 255; // x = 0b11111111; // x = 0xff;
  output(x);

  //2. blinking led
  volatile long i;
  for(i=0; i<1000000; i++)
  x = 0; //command all led off
  output(x); //set command
  for(i=0; i<1000000; i++)
  x = 255; // command all led on
  output(x); // set command

  //3. top-bottom-top led sequence
  //top-bottom blink
  for(x=0;x<8;x++)
  {
    output((1 << x));
    for(i=0;i<1000000;i++);
  }
  //bottom-top
    for(x=7;x>=0;x--)
  {
    output((1 << x));
    for(i=0;i<1000000;i++);
  }
}