From d6f38d0dfc4f602a6c790fd470deb2b2fd23da77 Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Sun, 22 Aug 2010 16:16:14 +0200
Subject: [PATCH 1/1] serial support

---
 bmc/.gitignore |  3 +++
 bmc/Makefile   |  4 ++--
 bmc/bmc.c      | 52 +++++++++++++++++++++++++++-----------------------
 bmc/usart.c    | 35 +++++++++++++++++++++++++++++++++
 bmc/usart.h    |  3 +++
 5 files changed, 71 insertions(+), 26 deletions(-)
 create mode 100644 bmc/.gitignore
 create mode 100644 bmc/usart.c
 create mode 100644 bmc/usart.h

diff --git a/bmc/.gitignore b/bmc/.gitignore
new file mode 100644
index 0000000..1fcc48e
--- /dev/null
+++ b/bmc/.gitignore
@@ -0,0 +1,3 @@
+bmc
+bmc.bin
+*.o
diff --git a/bmc/Makefile b/bmc/Makefile
index 2e566d0..7915e96 100644
--- a/bmc/Makefile
+++ b/bmc/Makefile
@@ -1,5 +1,5 @@
 CC=avr-gcc
-CFLAGS=-mmcu=atmega16 -g
+CFLAGS=-mmcu=atmega16 -DF_CPU=8000000UL -Wall -g
 OBJCOPY=avr-objcopy
 PROG=dragon_jtag
 PORT=usb
@@ -7,7 +7,7 @@ PMCU=m16
 
 all: bmc.bin
 
-bmc: bmc.o
+bmc: bmc.o usart.o
 
 bmc.bin: bmc
 	$(OBJCOPY) -j .text -j .data -O binary $^ $@
diff --git a/bmc/bmc.c b/bmc/bmc.c
index 06a3829..a0387b3 100644
--- a/bmc/bmc.c
+++ b/bmc/bmc.c
@@ -1,24 +1,28 @@
-#define F_CPU 1000000UL
-
-#include <avr/io.h>
-
-int main(void)
-{
-	uint8_t pb = 0x00;
-	int8_t dir = 1;
-	volatile uint16_t i;
-
-	DDRB = 0xff;
-
-	while(1) {
-		pb += dir;
-		PORTB = pb;
-
-		for (i = 0; i < (pb<<5); i++) {}
-
-		if ((pb == 0) || (pb == 0xff))
-			dir = -dir;
-	}
-
-	return 0;
-}
+#include <avr/io.h>
+#include <stdio.h>
+#include "usart.h"
+
+int main(void)
+{
+	uint8_t pb = 0x00;
+	int8_t dir = 1;
+	volatile uint16_t i;
+
+	DDRB = 0xff;
+
+	usart_init();
+
+	printf("Hallo!\n");
+
+	while(1) {
+		pb += dir;
+		PORTB = pb;
+
+		for (i = 0; i < (pb<<5); i++) {}
+
+		if ((pb == 0) || (pb == 0xff))
+			dir = -dir;
+	}
+
+	return 0;
+}
diff --git a/bmc/usart.c b/bmc/usart.c
new file mode 100644
index 0000000..36ba83c
--- /dev/null
+++ b/bmc/usart.c
@@ -0,0 +1,35 @@
+#include <avr/io.h>
+#include <stdio.h>
+
+#include "usart.h"
+
+#define UBRR_VAL ((F_CPU+BAUD*8)/(BAUD*16)-1)
+#define BAUD_REAL (F_CPU/(16*(UBRR_VAL+1)))
+#define BAUD_ERROR ((BAUD_REAL*1000)/BAUD)
+
+#if ((BAUD_ERROR<990) || (BAUD_ERROR>1010))
+#error Systematischer Fehler der Baudrate grösser 1% und damit zu hoch! 
+#endif 
+
+int usart_put(char c, FILE *stream)
+{
+	if (c == '\n')
+		usart_put('\r', stream);
+
+	while(!(UCSRA & (1<<UDRE))) {}
+	UDR = c;
+	return 0;
+}
+
+static FILE usart_stdout = FDEV_SETUP_STREAM(usart_put, NULL, _FDEV_SETUP_WRITE);
+
+void usart_init()
+{
+	UCSRB |= (1<<TXEN);
+	UCSRC |= (1<<URSEL)|(1 << UCSZ1)|(1 << UCSZ0);
+
+	UBRRH = UBRR_VAL >> 8;
+	UBRRL = UBRR_VAL & 0xFF;
+
+	stdout = &usart_stdout;
+}
diff --git a/bmc/usart.h b/bmc/usart.h
new file mode 100644
index 0000000..d0ce4a5
--- /dev/null
+++ b/bmc/usart.h
@@ -0,0 +1,3 @@
+#define BAUD 9600UL
+
+void usart_init();
-- 
2.39.5