walk96.c

//
//    This file is part of Dire Wolf, an amateur radio packet TNC.
//
//    Copyright (C) 2015  John Langner, WB2OSZ
//
//    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 2 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/>.
//


//#define DEBUG 1

/*------------------------------------------------------------------
 *
 * Module:      walk96.c
 *
 * Purpose:   	Quick hack to read GPS location and send very frequent 
 *		position reports frames to a KISS TNC.
 *
 *		
 *---------------------------------------------------------------*/

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <math.h>

#include "direwolf.h"
#include "config.h"
#include "ax25_pad.h"
#include "textcolor.h"
#include "latlong.h"
#include "dwgps.h"
#include "encode_aprs.h"
#include "serial_port.h"
#include "kiss_frame.h"


#define MYCALL "WB2OSZ"			/************ Change this if you use it!!!  ***************/

#define HOWLONG 20			/* Run for 20 seconds then quit. */



static MYFDTYPE tnc;

static void walk96 (int fix, double lat, double lon, float knots, float course, float alt);



int main (int argc, char *argv[])
{
	struct misc_config_s config;
	char cmd[100];
	int debug_gps = 0;
	int n;


	// TD-D72A USB - Look for Silicon Labs CP210x.
	// Just happens to be same on desktop & laptop.

	tnc = serial_port_open ("COM5", 9600);	
	if (tnc == MYFDERROR) {
	  text_color_set (DW_COLOR_ERROR);
          dw_printf ("Can't open serial port to KISS TNC.\n");
	  exit (EXIT_FAILURE);	// defined in stdlib.h
  	}

	strlcpy (cmd, "\r\rhbaud 9600\rkiss on\rrestart\r", sizeof(cmd));
	serial_port_write (tnc, cmd, strlen(cmd));

	
	// USB GPS happens to be COM22

	memset (&config, 0, sizeof(config));
	strlcpy (config.gpsnmea_port, "COM22", sizeof(config.nmea_port));

	dwgps_init (&config, debug_gps);

	SLEEP_SEC(1);				/* Wait for sample before reading. */

	for (n=0; n<HOWLONG; n++) {

	  dwgps_info_t info;
	  dwfix_t fix;

	  fix = dwgps_read (&info);

	  if (fix > DWFIX_2D) {
	    walk96 (fix, info.dlat, info.dlon, info.speed_knots, info.track, info.altitude);
	  }
	  else if (fix < 0) {
	    text_color_set (DW_COLOR_ERROR);
            dw_printf ("Can't communicate with GPS receiver.\n");
	    exit (EXIT_FAILURE);
	  }
	  else  {
	    text_color_set (DW_COLOR_ERROR);
            dw_printf ("GPS fix not available.\n");
	  }
	  SLEEP_SEC(1);
	}


	// Exit out of KISS mode.

	serial_port_write (tnc, "\xc0\xff\xc0", 3);

	SLEEP_MS(100);
	exit (EXIT_SUCCESS);
}


/* Should be called once per second. */

static void walk96 (int fix, double lat, double lon, float knots, float course, float alt)
{
	static int sequence = 0;
	char comment[50];

	sequence++;
	snprintf (comment, sizeof(comment), "Sequence number %04d", sequence);


/*
 * Construct the packet in normal monitoring format.
 */

	int messaging = 0;
	int compressed = 0;

	char info[AX25_MAX_INFO_LEN];
	int info_len;

	char position_report[AX25_MAX_PACKET_LEN];


// TODO (high, bug):    Why do we see !4237.13N/07120.84W=PHG0000...   when all values set to unknown.


	info_len = encode_position (messaging, compressed,
		lat, lon, (int)(DW_METERS_TO_FEET(alt)), 
		'/', '=',
		G_UNKNOWN, G_UNKNOWN, G_UNKNOWN, "",	// PHGd
		(int)roundf(course), (int)roundf(knots),
		445.925, 0, 0,
		comment,
		info, sizeof(info));

	snprintf (position_report, sizeof(position_report), "%s>WALK96:%s", MYCALL, info);

	text_color_set (DW_COLOR_XMIT);
        dw_printf ("%s\n", position_report);

/*
 * Convert it into AX.25 frame.
 */
	packet_t pp;
	unsigned char ax25_frame[AX25_MAX_PACKET_LEN];
	int frame_len;

	pp = ax25_from_text (position_report, 1);

	if (pp == NULL) {
	  text_color_set (DW_COLOR_ERROR);
          dw_printf ("Unexpected error in ax25_from_text.  Quitting.\n");
	  exit (EXIT_FAILURE);	// defined in stdlib.h
	}

	ax25_frame[0] = 0;	// Insert channel before KISS encapsulation. 

	frame_len = ax25_pack (pp, ax25_frame+1);
	ax25_delete (pp);

/*
 * Encapsulate as KISS and send to TNC.
 */
	
	unsigned char kiss_frame[AX25_MAX_PACKET_LEN*2];
	int kiss_len;

	kiss_len = kiss_encapsulate (ax25_frame, frame_len+1, (unsigned char *)kiss_frame);

	//text_color_set (DW_COLOR_DEBUG);
        //dw_printf ("AX.25 frame length = %d, KISS frame length = %d\n", frame_len, kiss_len);

	//kiss_debug_print (1, NULL, kiss_frame, kiss_len);

	serial_port_write (tnc, kiss_frame, kiss_len);

}

/* end walk96.c */