#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <string.h>
#include <stdio.h>

#define F_CPU 16000000UL
#define RS_pin PB5
#define E_pin PB4
#define C1 PD0
#define C2 PD1
#define C3 PD2
#define C4 PD3

#ifndef XPCU
#define XPCU 16000000UL
#endif
#define __DELAY_BACKWARD_COMPATIBLE__

char call_matricial();
const char KEY[4][3] = {{'1','2','3'}, {'4','5','6'}, {'7', '8', '9'}, {'*', '0', '#'}};
int pressed = 0;

const float step_size = 0.0048828125;

int buzzer_status = 0;
unsigned long int frequency = 50;
int duty = 10;
int prescaler = 1;
unsigned int high_delay=0, low_delay=0;
int stop_buzzer = 0;

int allow_write = 1;
int allow = 1;
int counter=0;

unsigned long int get_frequency(int frequency[], int digits){
	unsigned long int result = 0;
	int i=0;

	for (i=0; i<digits; i++){
		result += (frequency[i])*pow(10, digits-1-i);
	}
	return result;
}

void delay_us(int d)
{
	_delay_us(d);
}
void delay_ms(int d)
{
	_delay_ms(d);
}

void iniciar_LCD(){
  _delay_ms(2);
  Entrar_cmd(0x33);                              //$33 for 4-bit mode
	_delay_us(100); 
	Entrar_cmd(0x32);                              //$32 for 4-bit mode
	_delay_us(100); 
  Entrar_cmd(0x28);                              //function set
  _delay_us(100);
  Entrar_cmd(0x0C);                              //Display ON/OFF
  _delay_us(100);
  Entrar_cmd(0x06);                              //Entry mode set
  _delay_us(100);
  Entrar_cmd(0x01);                              //Clear display
}
void Entrar_cmd(unsigned char cmd){
  PORTB &= ~(1<<RS_pin);                       //RS = 0
  PORTB = (PORTB & 0xF0) | (cmd>>4);             //nibble alto
  PORTB |= (1<<E_pin);                           //E = 1
  _delay_us(100); 
  PORTB &= ~(1<<E_pin);                          //E = 0
  _delay_us(100);
  PORTB = (PORTB & 0xF0) | (cmd & 0x0F);         //nibble bajo
  PORTB |= (1<<E_pin);                           //E = 1
  _delay_us(100); 
  PORTB &= ~(1<<E_pin);                          //E = 0
  _delay_us(100);
}
void Entrar_data(unsigned char data){
  PORTB |= (1<<RS_pin);                          //RS = 1
  PORTB = (PORTB & 0xF0) | (data>>4);            //nibble alto
  PORTB |= (1<<E_pin);                           //E = 1
  _delay_us(100); 
  PORTB &= ~(1<<E_pin);                          //E = 0
  _delay_us(100);
  PORTB = (PORTB & 0xF0) | (data & 0x0F);        //nibble bajo
  PORTB |= (1<<E_pin);                           //E = 1
  _delay_us(100); 
  PORTB &= ~(1<<E_pin);                          //E = 0
  _delay_us(100);
}
void goto_xy(unsigned char X, unsigned char Y){
  if (Y==0){
    Entrar_cmd(0x80 + X);
  }
  if (Y==1){
    Entrar_cmd(0xC0 + X);
  }
}
void mostrar_str(char *str){
  int i;
  for(i=0;str[i]!=0;i++)
    {
      Entrar_data(str[i]);
    }
}

ISR (TIMER1_OVF_vect){
	if (stop_buzzer==0){
		int n0=0,n1=0,n2=0,n3=0;
		if (buzzer_status==0){
			n0 = (high_delay)&0xF;
			n1 = (high_delay>>4)&0xF;
			n2 = (high_delay>>8)&0xF;
			n3 = (high_delay>>12)&0xF;
		}
		else{
			n0 = (low_delay)&0xF;
			n1 = (low_delay>>4)&0xF;
			n2 = (low_delay>>8)&0xF;
			n3 = (low_delay>>12)&0xF;
		}
		PORTC ^= 0b00000010;
		buzzer_status = !buzzer_status;
		TCNT1H = n3*16+n2;
		TCNT1L = n1*16+n0;	
	}
}

int main(void)
{
	ADMUX = 0b01000000;
	ADCSRA= 0x87; 
	DDRC = 0b00000010;
	PORTC = 0x00; 
	high_delay = 65536-(1/(float)frequency)*((float)duty/100)*XPCU/prescaler;
	low_delay = 65536-(1/(float)frequency)*(1-(float)duty/100)*XPCU/prescaler;
	TCCR1A = 0x00;
	TCCR1B = 0x01; 
	TIMSK1 = (1<<TOIE1);
	sei (); 
	stop_buzzer = 1;
	DDRB = 0xFF;
	PORTD = 0b00001111; 
	DDRD = 0b01110000;

	const char clean_string[] = "                    ";
	char string[50] = "";
	int input_ADC;
	
	int freq[7];
	
	int changed_result=0;
	int last_result = 0;
	int i=0;
	int set=0;
	int start=0;
	
	frequency=0;
	iniciar_LCD();
	goto_xy(0,0);
	mostrar_str("Freq: ");
	goto_xy(7, 0);
	sprintf(string, "%ld", frequency);
	mostrar_str(string);
	strcpy(string, " Hz");
	mostrar_str(string);
	
	goto_xy(0,1);
  mostrar_str("Vol : ");
	goto_xy(7,1);
	sprintf(string, "%d", duty);
	mostrar_str(string);
	strcpy(string, "%");
	mostrar_str(string);

	while(1){
		allow_write = 1;
		if ((allow_write && stop_buzzer==1) ||start==1){
			ADCSRA|=(1<<ADSC); 
			while((ADCSRA&(1<<ADIF))==0); 
			input_ADC = ADC & 1023;
			duty = (((float)input_ADC/1023))*100;	
			allow = 1;
			if (last_result!=duty && allow==1){
				last_result = duty;
				changed_result = 1;
				allow = 0;
			}
			start = 0;
		}
		char key = call_matricial();
		
		if (key!=' ' && pressed==0){
			if (set==0 && key!='*' && key!='#'){ 
				set = 1;
				i = 0;
				goto_xy(7+i, 0);
				mostrar_str(clean_string);
				goto_xy(7+i, 0);
				sprintf(string, "%c Hz", key);
				mostrar_str(string);
				
				freq[i] = key-'0';
				
				i+= 1;
				pressed = 1;
			}
			else{
				if (key!='*' && key!='#' && i!=7){
					if (i==0){
						goto_xy(7, 0);
						mostrar_str(clean_string);
						goto_xy(7, 0);
					}
					goto_xy(7+i, 0);
					sprintf(string, "%c Hz", key);
					mostrar_str(string);
					
					freq[i] = key-'0';
					
					i += 1;
				}
				else if (key=='*'){
					stop_buzzer = 1;
					PORTC &= 0x00; // Off
					set = 0;
				}
				else if (key=='#'){
					frequency = get_frequency(freq, i);
					high_delay = 65536-(1/(float)frequency)*((float)duty/100)*XPCU/prescaler;
					low_delay = 65536-(1/(float)frequency)*(1-(float)duty/100)*XPCU/prescaler;
					start = 1;
					stop_buzzer = 0;
					goto_xy(7, 0);
					mostrar_str(clean_string);
					goto_xy(7, 0);
					
					if(frequency > 99){
					sprintf(string, "%ld Hz", frequency+1);
					mostrar_str(string);
					set = 0;}

					else{
					sprintf(string, "%ld Hz", frequency);
					mostrar_str(string);
					set = 0;}
				}
				pressed = 1;
			}
		}
		if (changed_result){
			high_delay = 65536-(1/(float)frequency)*((float)duty/100)*XPCU/prescaler;
			low_delay = 65536-(1/(float)frequency)*(1-(float)duty/100)*XPCU/prescaler;
			goto_xy(7,1);
			mostrar_str(clean_string);
			goto_xy(7,1);
			sprintf(string, "%d", duty);
			mostrar_str(string);
			strcpy(string, "%");
			mostrar_str(string);
			changed_result = 0;
		}
	}
	return 0;
}

char call_matricial(){
	int column;
	for (column=0; column<3; column++){
		PORTD = (~(1 << (column+4)))|(0b00001111);

		if (!(PIND&0x01)){
			return KEY[0][column];
		}
		else if (!(PIND&0x02)){
			return KEY[1][column];
		}
		else if (!(PIND&0x04)){
			return KEY[2][column];
		}
		else if (!(PIND&0x08)){
			return KEY[3][column];
		}
	}
	delay_ms(13);
	pressed = 0;
	return ' ';
}