tabby/avr/uart.c

#include <stdio.h>

#include <avr/io.h>
#include <avr/interrupt.h>

#include <tabby/avr/uart.h>

#define BAUD TABBY_AVR_UART_BAUD

#include <util/setbaud.h>

void uart_init() {
    UBRR0H = UBRRH_VALUE;
    UBRR0L = UBRRL_VALUE;

#if USE_2X
    UCSR0A |= _BV(U2X0);
#else
    UCSR0A &= ~(_BV(U2X0));
#endif

    UCSR0B = _BV(RXEN0)  | _BV(TXEN0);
    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00);
}

int uart_putchar(char c, FILE *fh) {
    loop_until_bit_is_set(UCSR0A, UDRE0);

    UDR0 = c;

    return 0;
}

int uart_getchar(FILE *fh) {
    loop_until_bit_is_set(UCSR0A, RXC0);

    return UDR0;
}