ardupilot/libraries/GCS_MAVLink/GCS_MAVLink.h

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-

/// @file	GCS_MAVLink.h
/// @brief	One size fits all header for MAVLink integration.

#ifndef GCS_MAVLink_h
#define GCS_MAVLink_h

#include <AP_HAL.h>
#include <AP_Param.h>
#include <AP_Math.h>

// we have separate helpers disabled to make it possible
// to select MAVLink 1.0 in the arduino GUI build
#define MAVLINK_SEPARATE_HELPERS

#define MAVLINK_SEND_UART_BYTES(chan, buf, len) comm_send_buffer(chan, buf, len)

// define our own MAVLINK_MESSAGE_CRC() macro to allow it to be put
// into progmem
#define MAVLINK_MESSAGE_CRC(msgid) mavlink_get_message_crc(msgid)

#if CONFIG_HAL_BOARD == HAL_BOARD_APM1 || CONFIG_HAL_BOARD == HAL_BOARD_APM2
#include <util/crc16.h>
#define HAVE_CRC_ACCUMULATE
// only two telemetry ports on APM1/APM2
#define MAVLINK_COMM_NUM_BUFFERS 2
#else
// allow three telemetry ports on other boards
#define MAVLINK_COMM_NUM_BUFFERS 3
#endif

#include "include/mavlink/v1.0/ardupilotmega/version.h"

#if CONFIG_HAL_BOARD == HAL_BOARD_APM1 || CONFIG_HAL_BOARD == HAL_BOARD_APM2
// this allows us to make mavlink_message_t much smaller. It means we
// can't support the largest messages in common.xml, but we don't need
// those for APM1/APM2
#define MAVLINK_MAX_PAYLOAD_LEN 104
#else
#define MAVLINK_MAX_PAYLOAD_LEN 255
#endif

#include "include/mavlink/v1.0/mavlink_types.h"

/// MAVLink stream used for uartA
extern AP_HAL::BetterStream	*mavlink_comm_0_port;

/// MAVLink stream used for uartC
extern AP_HAL::BetterStream	*mavlink_comm_1_port;

#if MAVLINK_COMM_NUM_BUFFERS > 2
/// MAVLink stream used for uartD
extern AP_HAL::BetterStream	*mavlink_comm_2_port;
#endif

/// MAVLink system definition
extern mavlink_system_t mavlink_system;

/// Send a byte to the nominated MAVLink channel
///
/// @param chan		Channel to send to
/// @param ch		Byte to send
///
static inline void comm_send_ch(mavlink_channel_t chan, uint8_t ch)
{
    switch(chan) {
	case MAVLINK_COMM_0:
		mavlink_comm_0_port->write(ch);
		break;
	case MAVLINK_COMM_1:
		mavlink_comm_1_port->write(ch);
		break;
#if MAVLINK_COMM_NUM_BUFFERS > 2
	case MAVLINK_COMM_2:
		mavlink_comm_2_port->write(ch);
		break;
#endif
	default:
		break;
	}
}

void comm_send_buffer(mavlink_channel_t chan, const uint8_t *buf, uint8_t len);

/// Read a byte from the nominated MAVLink channel
///
/// @param chan		Channel to receive on
/// @returns		Byte read
///
uint8_t comm_receive_ch(mavlink_channel_t chan);

/// Check for available data on the nominated MAVLink channel
///
/// @param chan		Channel to check
/// @returns		Number of bytes available
uint16_t comm_get_available(mavlink_channel_t chan);


/// Check for available transmit space on the nominated MAVLink channel
///
/// @param chan		Channel to check
/// @returns		Number of bytes available
uint16_t comm_get_txspace(mavlink_channel_t chan);

#ifdef HAVE_CRC_ACCUMULATE
// use the AVR C library implementation. This is a bit over twice as
// fast as the C version
static inline void crc_accumulate(uint8_t data, uint16_t *crcAccum)
{
	*crcAccum = _crc_ccitt_update(*crcAccum, data);
}
#endif

/*
  return true if the MAVLink parser is idle, so there is no partly parsed
  MAVLink message being processed
 */
bool comm_is_idle(mavlink_channel_t chan);

#define MAVLINK_USE_CONVENIENCE_FUNCTIONS
#include "include/mavlink/v1.0/ardupilotmega/mavlink.h"

uint8_t mavlink_check_target(uint8_t sysid, uint8_t compid);

// return a MAVLink variable type given a AP_Param type
uint8_t mav_var_type(enum ap_var_type t);

// return CRC byte for a mavlink message ID
uint8_t mavlink_get_message_crc(uint8_t msgid);

// severity levels used in STATUSTEXT messages
enum gcs_severity {
    SEVERITY_LOW=1,
    SEVERITY_MEDIUM,
    SEVERITY_HIGH,
    SEVERITY_CRITICAL,
    SEVERITY_USER_RESPONSE
};

#endif // GCS_MAVLink_h