led-controller/firmware/uart.c

60 lines
1.8 KiB
C

/* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* This is part of the LED light controller program.
* It handles the USART configuration
*/
#include <stdint.h> /* Standard Integer Types */
#include <stdio.h> /* Standard IO facilities */
#include <stdlib.h> /* General utilities */
#include <avr/io.h> /* AVR device-specific IO definitions */
#include "uart.h"
#include <util/setbaud.h> /* Helper macros for baud rate calculations */
FILE uart_output = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ);
FILE uart_io = FDEV_SETUP_STREAM(uart_putchar, uart_getchar, _FDEV_SETUP_RW);
/* configure serial port */
void uart_init(void)
{
UBRR0H = UBRRH_VALUE;
UBRR0L = UBRRL_VALUE;
#if USE_2X
UCSR0A |= (1<<U2X0);
#else
UCSR0A &= ~(1<<U2X0);
#endif
UCSR0C = (1<<UCSZ01)|(1<<UCSZ00); /* 8N1 bit data */
UCSR0B = (1<<RXEN0)|(1<<TXEN0); /* enable RX and TX */
UCSR0B |= (1<<RXCIE0); /* enable RX complete interrupt */
}
void uart_putchar(char c, FILE *stream)
{
if (c == '\n') {
uart_putchar('\r', stream);
}
loop_until_bit_is_set(UCSR0A, UDRE0);
UDR0 = c;
}
char uart_getchar(FILE *stream)
{
loop_until_bit_is_set(UCSR0A, RXC0); /* Wait until data exists. */
return UDR0;
}