From 7fdf8c1dc14a54b56549f079a7adb3cf6e329b4b Mon Sep 17 00:00:00 2001
From: Marvin Blum <marvin@marvinblum.de>
Date: Tue, 21 Mar 2017 16:50:13 +0100
Subject: [PATCH] Finished serial functions.

---
 compile  |  3 ++-
 main.c   | 33 ++++++++-------------------------
 pins.c   |  2 +-
 pins.h   |  1 +
 serial.c | 40 ++++++++++++++++++++++++++++++++++++++++
 serial.h |  8 ++++++++
 6 files changed, 60 insertions(+), 27 deletions(-)
 create mode 100644 serial.c
 create mode 100644 serial.h

diff --git a/compile b/compile
index 557efb9..65e703a 100755
--- a/compile
+++ b/compile
@@ -1,9 +1,10 @@
 #!/bin/bash
 
 mkdir build
+avr-gcc -Os -DF_CPU=16000000UL -mmcu=atmega328p -c -o build/serial.o -Wall serial.c
 avr-gcc -Os -DF_CPU=16000000UL -mmcu=atmega328p -c -o build/pins.o -Wall pins.c
 avr-gcc -Os -DF_CPU=16000000UL -mmcu=atmega328p -c -o build/main.o -Wall main.c
-avr-gcc -mmcu=atmega328p build/main.o build/pins.o -o build/main
+avr-gcc -mmcu=atmega328p build/*.o -o build/main
 avr-objcopy -O ihex -R .eeprom build/main build/main.hex
 avrdude -F -V -c arduino -p ATMEGA328P -P $1 -b 57600 -U flash:w:build/main.hex
 rm -r build
diff --git a/main.c b/main.c
index f234c55..d294ba6 100644
--- a/main.c
+++ b/main.c
@@ -1,22 +1,16 @@
 #include <avr/io.h>
 #include <util/delay.h>
+#include "serial.h"
 #include "pins.h"
 
-#define USART_BAUDRATE 9600
-#define BAUD_PRESCALE (((16000000UL/(USART_BAUDRATE*16UL)))-1)
-
 void loop();
 
 int main(){
-	digitalPinMode(6, INPUT);
+	/*digitalPinMode(6, INPUT);
 	digitalPinMode(7, INPUT);
-	digitalPinMode(12, OUTPUT);
+	digitalPinMode(12, OUTPUT);*/
 
-	// TODO verstehen und dann in Funktion packen
-	UCSR0B |= (1<<RXEN0)|(1<<TXEN0);
-	UCSR0C |= (1<<UCSZ00)|(1<<UCSZ01);
-	UBRR0H  = BAUD_PRESCALE>>8;
-	UBRR0L  = BAUD_PRESCALE;
+	serial_init(9600);
 
 	while(1){
 		loop();
@@ -31,20 +25,9 @@ void loop(){
 		digitalWrite(12, LOW);
 	}*/
 
-	// TODO verstehen und dann in Funktion packen
-	while(!(UCSR0A&(1<<UDRE0)));
-	UDR0 = 'h';
-	while(!(UCSR0A&(1<<UDRE0)));
-	UDR0 = 'e';
-	while(!(UCSR0A&(1<<UDRE0)));
-	UDR0 = 'l';
-	while(!(UCSR0A&(1<<UDRE0)));
-	UDR0 = 'l';
-	while(!(UCSR0A&(1<<UDRE0)));
-	UDR0 = 'o';
-	while(!(UCSR0A&(1<<UDRE0)));
-	UDR0 = '\n';
-//	while(!(SPSR&(1<<SPIF)));
+	char buffer[5];
+	serial_read(buffer, 5);
+	serial_write(buffer, 5);
 
-	_delay_ms(1000);
+	_delay_ms(100);
 }
diff --git a/pins.c b/pins.c
index 67678ad..81e9536 100644
--- a/pins.c
+++ b/pins.c
@@ -116,4 +116,4 @@ void analogWrite(unsigned char pin, unsigned char value){
 	else{
 		PORTC &= ~_BV(DDC0+pin);
 	}
-}
\ No newline at end of file
+}
diff --git a/pins.h b/pins.h
index 7187c74..c89b043 100644
--- a/pins.h
+++ b/pins.h
@@ -6,6 +6,7 @@ extern const unsigned char HIGH;
 extern const unsigned char INPUT;
 extern const unsigned char OUTPUT;
 
+// rename underscore
 void digitalPinMode(unsigned char, unsigned char);
 int digitalRead(unsigned char);
 void digitalWrite(unsigned char, unsigned char);
diff --git a/serial.c b/serial.c
new file mode 100644
index 0000000..6f90b0c
--- /dev/null
+++ b/serial.c
@@ -0,0 +1,40 @@
+#include "serial.h"
+#include <avr/io.h>
+
+void serial_init(unsigned int baud){
+	unsigned long baud_prescale = ((16000000UL/(baud*16UL)))-1;
+
+	// enable transmitter and receiver
+	UCSR0B |= (1<<RXEN0)|(1<<TXEN0);
+
+	// set frame format (8 data bits, 2 stop bits)
+	UCSR0C |= (1<<UCSZ00)|(1<<UCSZ01);
+
+	// set baudrate (16 bit)
+	UBRR0H  = baud_prescale>>8;
+	UBRR0L  = baud_prescale;
+}
+
+void serial_write(char* data, unsigned int n){
+	unsigned int i;
+
+	for(i = 0; i < n; i++){
+		// wait for empty tx buffer
+		while(!(UCSR0A&(1<<UDRE0)));
+
+		// write to tx register
+		UDR0 = data[i];
+	}
+}
+
+void serial_read(char* data, unsigned int n){
+	unsigned int i;
+
+	for(i = 0; i < n; i++){
+		// wait until data is available in rx buffer
+		while(!(UCSR0A&(1<<RXC0)));
+
+		// store in data array
+		data[i] = UDR0;
+	}
+}
diff --git a/serial.h b/serial.h
new file mode 100644
index 0000000..ccbe788
--- /dev/null
+++ b/serial.h
@@ -0,0 +1,8 @@
+#ifndef SERIAL_H_
+#define SERIAL_H_
+
+void serial_init(unsigned int);
+void serial_write(char*, unsigned int);
+void serial_read(char*, unsigned int);
+
+#endif