#include <avr/io.h>
#include <util/delay.h>


#define F_CPU 1600000UL
#define RS 6
#define E  5

void send_a_command (unsigned char command);
void send_a_character(unsigned char character);
void send_a_number(int a);
void send_a_string(char *a);



void avr_setup(void)
{
    DDRA = 0xFF;    //all outputs
    DDRB = 0x00;    //PORTB input for buttons
    PORTB = 0xFF;   //pullups all on
    DDRA = 0xFF;
    DDRD = 0xFF;
}


int main(void)
{
    int a=0;
    int b=0;
    int c=0;
    int d=0;
    _delay_ms(50);
    send_a_command(0x01);// sending all clear command
    send_a_command(0x38);// 16*2 line LCD
    send_a_command(0x0E);// screen and cursor ON
    print_screen(a%10,b%10,c%10,d%10);// printing 4 digits
    avr_setup();

 while(1)
    {

        _delay_ms(1000);
        if (!(PINB & (1<<PB0)))
        {
            a +=1;
            print_screen(a%10,b%10,c%10,d%10);
        }
        if (!(PINB & (1<<PB1)))
        {
            b +=1;
            print_screen(a%10,b%10,c%10,d%10);
        }
        if (!(PINB & (1<<PB2)))
        {
            c +=1;
            print_screen(a%10,b%10,c%10,d%10);
        }
        if (!(PINB & (1<<PB3)))
        {
            d +=1;
            print_screen(a%10,b%10,c%10,d%10);
        }
        if(a%10==1&&b%10==2&&c%10==3&&d%10==4)
        {
            send_a_command(0x01);
            send_a_string("Open");
        }

    }
}

void send_a_string(char *a)
{
    for (int i=0;a[i]!='\0';i++)
    {
        send_a_character(a[i]);
    }
}
void send_a_command (unsigned char command)
{
    PORTA=command;
    PORTD&= ~(1<<RS);
    PORTD|= (1<<E);
    _delay_ms(50);
    PORTD&= ~(1<<E);
    PORTA =0;
}

void send_a_number(int a)
{
    char character = a + '0';
    PORTA=character;
    PORTD|= (1<<RS);
    PORTD|= (1<<E);
    _delay_ms(50);
    PORTD&= ~(1<<E);
    PORTA =0;
}

void send_a_character (unsigned char character)
{
    PORTA=character;
    PORTD|= (1<<RS);
    PORTD|= (1<<E);
    _delay_ms(50);
    PORTD&= ~(1<<E);
    PORTA =0;
}
void send_a_result(int a,int b,int c,int d)
{
    char aa=a+'0';
    char bb=b+'0';
    char cc=c+'0';
    char dd=d+'0';

    char result[4]= { aa,bb,cc,dd, };
    send_a_string(result);
}
void print_screen(int a,int b,int c,int d)
{
    send_a_command(0x01);// sending all clear command
    send_a_string("Enter Code:");
    send_a_result( a, b, c, d);
}