#include "uart.h"
#include <avr/io.h>
#include "mystd.h"
#include "utils.h"

#define BAUD_RATE  115200

#define UBRR_VALUE ((F_CPU / (8UL * BAUD_RATE)) - 1)

// uart is 115200 baud rate, 8 bits per word, no parrity and 1 stop bit
// 115200 8N1
void uart_init(void) {
	// Set baud rate
	UBRR0H	= (uint8_t)(UBRR_VALUE >> 8);
	UBRR0L	= (uint8_t)(UBRR_VALUE);

	UCSR0A |= _BV(U2X0);
	// Enable transmitter
	UCSR0B	= _BV(TXEN0) | _BV(RXEN0);

	// Set frame format: 8 data bits, no parity, 1 stop bit
	UCSR0C	= _BV(UCSZ01) | _BV(UCSZ00);

	// Set TX (PD1) as output
	DDRD   |= _BV(PD1);
}

void uart_tx(char data) {
	// wait for transmit buffer to be empty
	while (!(UCSR0A & _BV(UDRE0)))
		;
	// load data into transmit register
	UDR0 = data;
}

char uart_rx(void) {
	while (!(UCSR0A & _BV(RXC0)))
		;
	return UDR0;
}

void uart_sendstring(const char* str) {
	if (!str)
		return;
	while (*str) {
		uart_tx(*str);
		str++;
	}
}