#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

void init_display();
void init_timer0();

volatile uint8_t lcdx=0, lcdy=0; 
const char lcdcmd[4] = {??, ??, ??, ??};
unsigned char LCDline[4][16]={{"EE308 Midterm   "},
                              {"April 27th, 2023"},
                              {"EE308 Board v3.0"},
                              {"Keyboard ---->  "}};
const char LookUp[16] ={"0123456789ABCDEF"};

int main(void)
{   
    //_delay_ms(500);
    init_display();
    init_timer0();  // initialize timer0
    
    sei();  // enable global interrupts
    // loop forever
    while(1)
    {
        while((PINB|0xEF)==0xFF);
        while((PINB&0x10)==0x00);
        LCDline[3][15] = LookUp[PINB&0x0F];
    }
}

void init_display()
{
    DDRA = 0xFF;
    
    PORTC &= 0xAF;
    DDRC  |= 0x50;
    
    PORTC &= 0xBF;

    PORTA = 0x38;
    PORTC |= 0x10;
    PORTC &= 0xEF;
    PORTA = 0x0C;
    PORTC |= 0x10;
    PORTC &= 0xEF;
    PORTA = 0x01;
    PORTC |= 0x10;;
    PORTC &= 0xEF;  
    _delay_ms(2);
}

void init_timer0()
{
    TCCR0B |= (1<<CS02)|(1<<CS00);	// prescaler 1024
    TCNT0 = 0;			            // initialize counter
    TIMSK0 |= (1 << TOIE0);	        // enable overflow interrupt 
}

ISR(TIMER0_OVF_vect)
{
//    if(lcdptr==16) {
//        PORTC &= 0xBF;
//        PORTA = lcdcmd;
//        lcdptr = 0;
//        lcdcmd ^= 0x40;
//        lcdoff ^= 0x10;        
//    }
//    else {
//        PORTC |= 0x40;
//        PORTA = LCDline[lcdoff+lcdptr];
//        PORTC |= 0x10;
//        lcdptr++;
//    }
//    PORTC |= 0x10;
//    PORTC &= 0xEF;
}