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/****************************************************************************
*
* Copyright (c) 2012, 2013 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file mtk.cpp
*
* @author Thomas Gubler <thomasgubler@student.ethz.ch>
* @author Julian Oes <joes@student.ethz.ch>
*/
#ifndef MTK_H_
#define MTK_H_
#include "gps_helper.h"
#define MTK_SYNC1_V16 0xd0
#define MTK_SYNC1_V19 0xd1
#define MTK_SYNC2 0xdd
#define MTK_OUTPUT_5HZ "$PMTK220,200*2C\r\n"
#define MTK_SET_BINARY "$PGCMD,16,0,0,0,0,0*6A\r\n"
#define SBAS_ON "$PMTK313,1*2E\r\n"
#define WAAS_ON "$PMTK301,2*2E\r\n"
#define MTK_NAVTHRES_OFF "$PMTK397,0*23\r\n"
#define MTK_TIMEOUT_5HZ 400
#define MTK_BAUDRATE 38400
typedef enum {
MTK_DECODE_UNINIT = 0,
MTK_DECODE_GOT_CK_A = 1,
MTK_DECODE_GOT_CK_B = 2
} mtk_decode_state_t;
/** the structures of the binary packets */
#pragma pack(push, 1)
typedef struct {
uint8_t payload; ///< Number of payload bytes
int32_t latitude; ///< Latitude in degrees * 10^7
int32_t longitude; ///< Longitude in degrees * 10^7
uint32_t msl_altitude; ///< MSL altitude in meters * 10^2
uint32_t ground_speed; ///< velocity in m/s
int32_t heading; ///< heading in degrees * 10^2
uint8_t satellites; ///< number of sattelites used
uint8_t fix_type; ///< fix type: XXX correct for that
uint32_t date;
uint32_t utc_time;
uint16_t hdop; ///< horizontal dilution of position (without unit)
uint8_t ck_a;
uint8_t ck_b;
} gps_mtk_packet_t;
#pragma pack(pop)
#define MTK_RECV_BUFFER_SIZE 40
class MTK : public GPS_Helper
{
public:
MTK(const int &fd, struct vehicle_gps_position_s *gps_position);
~MTK();
int receive(unsigned timeout);
int configure(unsigned &baudrate);
private:
/**
* Parse the binary MTK packet
*/
int parse_char(uint8_t b, gps_mtk_packet_t &packet);
/**
* Handle the package once it has arrived
*/
void handle_message(gps_mtk_packet_t &packet);
/**
* Reset the parse state machine for a fresh start
*/
void decode_init(void);
/**
* While parsing add every byte (except the sync bytes) to the checksum
*/
void add_byte_to_checksum(uint8_t);
int _fd;
struct vehicle_gps_position_s *_gps_position;
mtk_decode_state_t _decode_state;
uint8_t _mtk_revision;
uint8_t _rx_buffer[MTK_RECV_BUFFER_SIZE];
unsigned _rx_count;
uint8_t _rx_ck_a;
uint8_t _rx_ck_b;
};
#endif /* MTK_H_ */
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