Add rtty code from previous hadie software

rtty.c

@@ -0,0 +1,84 @@
+/* hadie - High Altitude Balloon flight software              */
+/*============================================================*/
+/* Copyright (C)2010 Philip Heron <phil@sanslogic.co.uk>      */
+/*                                                            */
+/* This program is distributed under the terms of the GNU     */
+/* General Public License, version 2. You may use, modify,    */
+/* and redistribute it under the terms of this license. A     */
+/* copy should be included with this source.                  */
+
+#include "config.h"
+#include <stdint.h>
+#include <io.h>
+#include <util/delay.h>
+#include <pgmspace.h>
+
+#define RTTY_BAUD  (300)
+#define RTTY_DELAY (1000000 / RTTY_BAUD)
+
+/* MARK = Upper tone, Idle, bit  */
+#define TXENABLE (0x04)
+#define MARK  (0x02)
+#define SPACE (0x01)
+
+/* RTTY speed */
+uint16_t rtty_delay = (1000000 / RTTY_BAUD);
+//#define RTTY_DELAY rtty_delay
+
+void tx_baud(int baud)
+{
+	rtty_delay = 1000000 / baud;
+}
+
+inline void tx_bit(uint8_t b)
+{
+	PORTB &= ~(MARK | SPACE);
+	PORTB |= b;
+}
+
+void tx_byte(uint8_t byte)
+{
+	int i;
+	
+	/* Start bit */
+	tx_bit(SPACE);
+	_delay_us(RTTY_DELAY);
+	
+	/* 7 bit */
+	for(i = 0; i < 8; i++)
+	{
+		if(byte & 1 << i) tx_bit(MARK); else tx_bit(SPACE);
+		_delay_us(RTTY_DELAY);
+	}
+	
+	/* Stop bit 1 */
+	tx_bit(MARK);
+	_delay_us(RTTY_DELAY);
+	_delay_us(RTTY_DELAY / 2);
+}
+
+void tx_string(char *s)
+{
+	while(*s != '\0') tx_byte(*(s++));
+}
+
+void tx_string_P(PGM_P s)
+{
+	char b;
+	while((b = pgm_read_byte(s++)) != '\0') tx_byte(b);
+}
+
+void tx_packet(uint8_t *packet)
+{
+	int b;
+	for(b = 0; b <= PKT_SIZE; b++) tx_byte(packet[b]);
+}
+
+void tx_init()
+{
+	/* We use Port B pins 1, 2 and 3 - MARK by default */
+	tx_bit(MARK);
+	PORTB |= TXENABLE;
+	DDRB |= MARK | SPACE | TXENABLE;
+}
+

rtty.h

@@ -0,0 +1,22 @@
+/* hadie - High Altitude Balloon flight software              */
+/*============================================================*/
+/* Copyright (C)2010 Philip Heron <phil@sanslogic.co.uk>      */
+/*                                                            */
+/* This program is distributed under the terms of the GNU     */
+/* General Public License, version 2. You may use, modify,    */
+/* and redistribute it under the terms of this license. A     */
+/* copy should be included with this source.                  */
+
+#ifndef INC_RTTY_H
+#define INC_RTTY_H
+
+#include <stdint.h>
+#include <pgmspace.h>
+
+extern void rtx_baud(int baud);
+extern void rtx_string(char *s);
+extern void rtx_string_P(PGM_P s);
+extern void rtx_packet(uint8_t *packet);
+extern void rtx_init();
+
+#endif