/*
CPU1

HW:

ATmega644 14,7456MHz, 5V

Nastavenie: Interny OSC 14,7456MHZ, zmenené default fuses od výroby na -rW01100111

*/

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

#define SYSCLK (14745600.0)
#define USEC(usec) (usec*SYSCLK/1.0/256.0/14745600.0+0.5)   // timer clocks per microsecond

//define pre seriovu komunikaciu 14,7456MHz, baud 9600, chybovost 0,0%
#define FOSC 14745600 // Clock Speed
#define BAUD 9600
#define MYUBRR FOSC/16/BAUD-1

// Globalne premenne
char nastav_semafory = 0;

void USART_Init(unsigned int ubrr)
{
	// Set baud rate 
	UBRR0H = (unsigned char)(ubrr>>8);
	UBRR0L = (unsigned char)ubrr;

	// Enable receiver and transmitter
	UCSR0B = (1<<RXEN0)|(1<<TXEN0);
	
	// Set frame format: 8data, 2stop bit
	UCSR0C = (1<<USBS0)|(3<<UCSZ00);
}

volatile unsigned char s_posledna_poslana_hodnota = 0;
void USART_Transmit( unsigned char data ) {
	if (s_posledna_poslana_hodnota != data) {
		/* Wait for empty transmit buffer */
		while ( !( UCSR0A & (1<<UDRE0)) )
			;
		/* Put data into buffer, sends the data */
		UDR0 = data;
	}
}

unsigned char USART_Receive( void ) {
	// Wait for data to be received
	while ( !(UCSR0A & (1<<RXC0)) )
		;

	// Get and return received data from buffer
	return UDR0;
}

// Prerušenia
// >>>>> Prerušenie USART prijatý znak
ISR (USART0_RX_vect) {
	unsigned char s_vstup = 0;
	char s_vlak = 0;

	s_vstup = USART_Receive();

	// Zrusi prijatie zmien, ktore posle ten isty CPU, aby sa tu neobsadila trat cez vzdialene obsadenie
	if (s_posledna_poslana_hodnota == s_vstup) {
		goto g_koniec;
	}
	if (((s_vstup & (1 << 7)) == 0) & ((s_vstup & (1 << 6)) == 0) & ((s_vstup & (1 << 5)) == 0)) {
		// voľné
		goto g_koniec;
	}
	
	if (((s_vstup & (1 << 7)) == 0) & ((s_vstup & (1 << 6)) == 0) & ((s_vstup & (1 << 5)) > 0)) { s_vlak = 1; goto g_s_vlak; }
	if (((s_vstup & (1 << 7)) == 0) & ((s_vstup & (1 << 6)) > 0) & ((s_vstup & (1 << 5)) == 0)) { s_vlak = 2; goto g_s_vlak; }
	if (((s_vstup & (1 << 7)) == 0) & ((s_vstup & (1 << 6)) > 0) & ((s_vstup & (1 << 5)) > 0)) { s_vlak = 3; goto g_s_vlak; }
	if (((s_vstup & (1 << 7)) > 0) & ((s_vstup & (1 << 6)) == 0) & ((s_vstup & (1 << 5)) == 0)) { s_vlak = 4; goto g_s_vlak; }
	if (((s_vstup & (1 << 7)) > 0) & ((s_vstup & (1 << 6)) == 0) & ((s_vstup & (1 << 5)) > 0)) { s_vlak = 5; goto g_s_vlak; }
	g_s_vlak:
	if (s_vlak > 0) {
		ZmenTratVlaku(s_vlak, s_vstup & 0x1F);
	}
	
	if (((s_vstup & (1 << 7)) > 0) & ((s_vstup & (1 << 6)) > 0) & ((s_vstup & (1 << 5)) == 0)) { //uvolní trať
		UvolniTrat(s_vstup & 0x1F);
		goto g_koniec;
	}
	
	if (((s_vstup & (1 << 7)) > 0) & ((s_vstup & (1 << 6)) > 0) & ((s_vstup & (1 << 5)) > 0)) { //obsadí trať
		ObsadiTrat(s_vstup & 0x1F);
	}
	g_koniec:
	;
}

int main(void) {
	//Nastavenie vstupov a výstupov
	DDRA = 0x00;
	PORTA = 0x00;
	DDRB = 0x0F;
	PORTB = 0x00;
	DDRC = 0x00;
	PORTC = 0x00;
	DDRD = 0xFE;
	PORTD = 0x00;

// Inicializacia seriovej komunikacie USART0 a prerusenia pre prijem
	USART_Init(MYUBRR);
	UCSR0B |= (1 << RXCIE0); // Povolenie prerušnia pre príjem RX
	sei(); // Povolenie globálneho prerušenia

	while(1) {
		//........
	}
    return (0);
}