added UART methods

src/Makefile

@@ -19,7 +19,7 @@ PROGRAMMER=usbtiny
 #AVRDUDE=avrdude -p $(DEVICE) -P $(PORT) -c $(PROGRAMMER)
 FLASHER=avrdude -p $(DEVICE) -c $(PROGRAMMER)
 # source files to compile
-SRC = main.c
+SRC = main.c uart.c
 # object files.
 OBJ = $(SRC:.c=.o)
 # listing files.
@@ -36,6 +36,9 @@ verify:
 		exit 1; \
 	fi
 
+reset:
+	$(FLASHER)
+
 read-fuse:
 	$(FLASHER) -U lfuse:r:lfuse.raw:r -U hfuse:r:hfuse.raw:r -U efuse:r:efuse.raw:r
 

src/main.c

@@ -5,12 +5,15 @@
 #include <avr/io.h> /* AVR device-specific IO definitions */
 #include <util/delay.h> /* Convenience functions for busy-wait delay loops */
 
-#define LED PD6 /* LED port */
-
+#include "main.h"
+#include "uart.h"
 
 static void ioinit(void)
 {
 	DDRD = (1<<LED); /* set LED pin as output */
+	uart_init(); /* initialize UART */
+	stdout = &uart_output;
+	stdin  = &uart_input;
 }
 
 int main(void)
@@ -19,6 +22,8 @@ int main(void)
 
 	uint8_t i;
 
+	puts("Hello world!");
+	
 	/* blink LED */
 	for (i = 0; i < 100; i++) {
 		PIND |= (1<<LED); /* toggle LED */

src/main.h

@@ -0,0 +1,3 @@
+#define LED PD6 /* LED port */
+
+static void ioinit(void);

src/uart.c

@@ -0,0 +1,40 @@
+#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 */
+}
+
+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;
+}

src/uart.h

@@ -0,0 +1,10 @@
+#define BAUD 115200 /* serial baudrate */
+
+FILE uart_output;
+FILE uart_input;
+FILE uart_io;
+
+void uart_init(void);
+void uart_putchar(char c, FILE *stream);
+char uart_getchar(FILE *stream);
+