mavlink_parameters.c

/*******************************************************************************
 
 Copyright (C) 2011 Lorenz Meier lm ( a t ) inf.ethz.ch
 
 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 3 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/>.
 
 ****************************************************************************/

#include "mavlink_missionlib_data.h"
#include "mavlink_parameters.h"
#include "math.h" /* isinf / isnan checks */

extern mavlink_system_t mavlink_system;
extern mavlink_pm_storage pm;

extern void mavlink_missionlib_send_message(mavlink_message_t* msg);
extern void mavlink_missionlib_send_gcs_string(const char* string);

void mavlink_pm_message_handler(const mavlink_channel_t chan, const mavlink_message_t* msg)
{
	switch (msg->msgid)
	{
		case MAVLINK_MSG_ID_PARAM_REQUEST_LIST:
			{
				// Start sending parameters
				pm.next_param = 0;
				mavlink_missionlib_send_gcs_string("PM SENDING LIST");
			}
			break;
		case MAVLINK_MSG_ID_PARAM_SET:
		{
			mavlink_param_set_t set;
			mavlink_msg_param_set_decode(msg, &set);
			
			// Check if this message is for this system
			if (set.target_system == mavlink_system.sysid && set.target_component == mavlink_system.compid)
			{
				char* key = set.param_id;
				
				for (uint16_t i = 0; i < MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN; i++)
				{
					bool match = true;
					for (uint16_t j = 0; j < MAVLINK_MSG_PARAM_VALUE_FIELD_PARAM_ID_LEN; j++)
					{
						// Compare
						if (pm.param_names[i][j] != key[j])
						{
							match = false;
						}
						
						// End matching if null termination is reached
						if (pm.param_names[i][j] == '\0')
						{
							break;
						}
					}
					
					// Check if matched
					if (match)
					{
						// Only write and emit changes if there is actually a difference
						// AND only write if new value is NOT "not-a-number"
						// AND is NOT infinity
						if (pm.param_values[i] != set.param_value
							&& !isnan(set.param_value)
							&& !isinf(set.param_value))
						{
							pm.param_values[i] = set.param_value;
							// Report back new value
#ifndef MAVLINK_USE_CONVENIENCE_FUNCTIONS
							mavlink_message_t tx_msg;
							mavlink_msg_param_value_pack_chan(mavlink_system.sysid,
															  mavlink_system.compid,
															  MAVLINK_COMM_0,
															  &tx_msg,
															  pm.param_names[i],
															  pm.param_values[i],
															  MAVLINK_TYPE_FLOAT,
															  pm.size,
															  i);
							mavlink_missionlib_send_message(&tx_msg);
#else
							mavlink_msg_param_value_send(MAVLINK_COMM_0,
														 pm.param_names[i],
														 pm.param_values[i],
														 MAVLINK_TYPE_FLOAT,
														 pm.size,
														 i);
#endif
							
							mavlink_missionlib_send_gcs_string("PM received param");
						} // End valid value check
					} // End match check
				} // End for loop
		} // End system ID check
		
	} // End case
			break;
			
	} // End switch
	
}
	
	/**
	 * @brief Send low-priority messages at a maximum rate of xx Hertz
	 *
	 * This function sends messages at a lower rate to not exceed the wireless
	 * bandwidth. It sends one message each time it is called until the buffer is empty.
	 * Call this function with xx Hertz to increase/decrease the bandwidth.
	 */
	void mavlink_pm_queued_send(void)
	{
		//send parameters one by one
		if (pm.next_param < pm.size)
		{
			//for (int i.. all active comm links)
#ifndef MAVLINK_USE_CONVENIENCE_FUNCTIONS
			mavlink_message_t tx_msg;
			mavlink_msg_param_value_pack_chan(mavlink_system.sysid,
											  mavlink_system.compid,
											  MAVLINK_COMM_0,
											  &tx_msg,
											  pm.param_names[pm.next_param],
											  pm.param_values[pm.next_param],
											  MAVLINK_TYPE_FLOAT,
											  pm.size,
											  pm.next_param);
			mavlink_missionlib_send_message(&tx_msg);
#else
			mavlink_msg_param_value_send(MAVLINK_COMM_0,
										 pm.param_names[pm.next_param],
										 pm.param_values[pm.next_param],
										 MAV_DATA_TYPE_FLOAT,
										 pm.size,
										 pm.next_param);
#endif
			pm.next_param++;
		}
	}