/*Connect 8 LEDs to an 8-bit port
Connect 8 Switches to an 8-bit port
4. Press any switch glow 7th LED, delay,6th LED, delay …*/

//Registers for I/O ports
#define PORTF_DIR_REG   ((volatile unsigned char *) 0x30)  // Data Direction Register for PORTF
#define PORTK_DIR_REG   ((volatile unsigned char *) 0x107) // Data Direction Register for PORTK
#define PORTF_OUT_REG   ((volatile unsigned char *) 0x31)  // Data Register for PORTF (OUTPUT REGISTER)
#define PORTK_IN_REG   ((volatile unsigned char *) 0x106) // input Register for PORTK

//Macro for swtch to control the LED's
#define SWITCH 0xFF

void setup ()
{
  init_func();
}

//delay function
void delay_func()
{
    volatile long i;
    for (i = 0;i < 400000;i++);
}

//8 LED's are connected to PORTF and 8 switches are connected to PORTK 
void init_func() {
  //Set PORTF pins as an output
  *PORTF_DIR_REG = 0xFF;
  //Set PORK pins as an input
  *PORTK_DIR_REG = 0x00; 
}

//Main function
void loop() {
    volatile char x;
    int i;
    while (1) {
      //read the input PORT
      x = *PORTK_IN_REG;
      // Check if the switch is pressed
      if (x & SWITCH) {
       // Short debounce delay
        delay_func();
        // Glow LEDs sequentially
        for (i = 7;i >= 0;i--) {
          *PORTF_OUT_REG = (1 << i);
          delay_func();
        }
      }
      // Turn off all LEDs after the sequence
      *PORTF_OUT_REG = 0x00;
    }
}