#include <Mega32.h>
#include <delay.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#define t0	500  //Define task1 timer0 interval of execution 
#define t1  30		// for debounce
#define pin 0x55
#define headerPacket 50 
#define but0 0x22
#define but1 0x33
#define but2 0x44

int time0, time1; 
int leds;

char button0Flag, button1Flag, button2Flag;
char state0, state1, state2;
int counter;


void debounce0(void);
void debounce1(void);
void debounce2(void);


//************************************************************************
interrupt [TIM0_COMP] void timer0_compare(void) 
{
       if (time0>0)--time0;
       if (time1>0)--time1;

}

//************************************************************************
// thi task will simlply flash the leds
void task0 (){ 
	 time0=t0;
     leds = leds ^ 0xff;
     PORTD= leds;
}                   

// the init routine
void init (){

	//set up the ports
	DDRD=0xff;  // PORT D is output
	leds = 0x00;
	PORTD= leds;
	
	DDRB=0x00;	// PORT B is an input
	PORTB = 0xff;	// set the pull ups
	
	//set up timer 0  
   TIMSK = 2;       	//turn on timer 0 cmp match ISR 
   OCR0 = 249;         //set the compare re to 250 time ticks
 	TCCR0=0b00001011;   //prescalar to 64 and turn on clear-on-match
     
  //Setup rs232 transmisson
   UCSRB = 0x08; 		//transmit only on PORTD.1 
	UBRRL = 207;		//setup on 4800 baud	
	
	// start isrs
	#asm
 		sei
	#endasm
	
	// general initialization
	state0=1; 
	state1=1; 
	state2=1;
	button0Flag=0;
	button1Flag=0; 
	button2Flag =0;
	time0 = t0;
	time1 = t1;


}
                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
//************************************************************************
void main(void)
{

	init();
	while (1) {
		//putchar (0xaa);   debug purposes
		
      //  toggle leds      
		if (time0==0) {
			task0();
		} 
		
		// debounces the buttons
		if (time1==0)	
		{
			time1 = t1;  	
			debounce0(); 		
			debounce1(); 	
			debounce2(); 	
		}
	
	// if each any of the buttons are pressed.
	// send the dc balanced initial packets of 0xaa
	// then send the header packet key
	// then send the command (ie, button number key)
	// then send the end packet
  	if (button0Flag) {
  				button0Flag =0;
		for (counter =0; counter < headerPacket; counter++)
		{			putchar(0xaa);  				  	
         }
       	
					putchar(pin); 
					putchar(but0);					
					putchar(pin); 
					leds = leds ^ 0xff;
					PORTD= leds;
  	} 
  	
  	if (button1Flag) {
  				button1Flag =0;
					for (counter =0; counter < headerPacket; counter++)
					{			putchar(0xaa);  				  	
          }
        		  	
					putchar(pin); 
					putchar(but1);

					putchar(pin); 
					leds = leds ^ 0xff;
					PORTD= leds;
				
  	} 
  	
  	if (button2Flag) {
  				button2Flag =0;
					for (counter =0; counter < headerPacket; counter++)
					{			putchar(0xaa);  				  	
          }
          			  	
					putchar(pin);
					putchar(but2); 
					putchar(pin); 
					leds = leds ^ 0xff;
					PORTD= leds;
					
  	}
  	
	}
}

void debounce0 (void)
{ 

	switch (state0) {
	case 1:	
		if (PINB.0 ==0)	state0 =2; 
		break;
	case 2:
		if (PINB.0 ==0) {
			state0 =3;
			button0Flag =1;
		}
		else  state0 =1;
		break;
	case 3:
		if (PINB.0 ==0) state0 =3;
		else  state0=4; 

		break;
	case 4:
		if (PINB.0 == 0) state0=3;
		else {
			button0Flag =0;
			state0=1;
	  	}
	  break;
	}
}    

void debounce1 (void)
{   	
	switch (state1) {
	case 1:	
		if (PINB.1 ==0)	state1 =2; 
		break;
	case 2:
		if (PINB.1 ==0) {
			state1 =3;
			button1Flag =1;
		}
		else  state1 =1;
		break;
	case 3:
		if (PINB.1 ==0) state1 =3;
		else  state1=4; 

		break;
	case 4:
		if (PINB.1 == 0) state1=3;
		else {
			button1Flag =0;
			state1=1;
	  	}
	  	break;
	}
}    



void debounce2 (void)
{   	
	switch (state2) {
	case 1:	
		if (PINB.2 ==0)	state2 =2; 
		break;
	case 2:
		if (PINB.2 ==0) {
			state2 =3;
			button2Flag =1;
		}
		else  state2 =1;
		break;
	case 3:
		if (PINB.2 ==0) state2 =3;
		else  state2=4; 

		break;
	case 4:
		if (PINB.2 == 0) state2=3;
		else {
			button2Flag =0;
			state2=1;
	  	}
	  	break;
	}
}