AVR-Playground/uart.c

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

// 9600 seems to be the highest the ATmega328P can handle in this config
#define BAUD 9600  
#include <util/setbaud.h>

void initUART() {
    // Set baud rate with precalculated values (see setbaud.h)
    UBRR0H = UBRRH_VALUE;
    UBRR0L = UBRRL_VALUE;
    // Enable receiver and transmitter
    UCSR0B |= (1 << RXEN0) | (1 << TXEN0);
    // Set frame format: 8 data, 1 stop bit
    UCSR0C |= (1 << UCSZ01) | (1 << UCSZ00);
}

void UART_transmit(uint8_t data) {
    // Wait for empty transmit buffer
    while (!(UCSR0A & (1 << UDRE0)));
    // Put data into buffer, sends the data
    UDR0 = data;
}

void UART_println(const char *str) {
    // Transmit each character until NULL character is encountered
    while (*str) UART_transmit(*str++);
    // Transmit carriage return and line feed characters
    UART_transmit('\r');
    UART_transmit('\n');
}