Multiwii Communications :: QUARC Communications

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Table of Contents > QUARC > User's Guide > Communications

Multiwii Communications

Multiwii is a flight controller communications protocol originally developed for a project using the Nintendo Wiimote. Information about Multiwii may be found at the Multiwii website.

The Multiwii communications blockset may be found under the QUARC Targets/Communications/Multiwii library in the Simulink Library Browser. This blockset includes a large set of blocks designed to interface with Multiwii-based auto-pilot systems. These blocks are designed to be used with non-blocking I/O and are typically used with a serial port connection to the auto-pilot.

Warning

Note that most auto-pilots only support a subset of the blocks below. For example, an auto-pilot may return zero values for features it does not support, such as GPS.

Multiwii communications are established with a flight controller using the Multiwii Connect block. The underlying protocol to use for Multiwii is determined using the standard QUARC URI paradigm for communications. For Multiwii, communications with the flight controller is typically based on a serial connection to the QUARC target platform. Hence, a URI such as serial://localhost:1?baud=115200,word=8,parity=none,stop=1 might be used.

Multiwii is a command-request protocol, so blocks that receive data send a packet to the flight controller requesting the data. The Multiwii blocks use blocking I/O so that the data is available immediately. Be aware that if the baud rate is low then the response time may be slow. For example, at 115200 baud only 11 bytes may be sent or received each sample time when the sampling period is one millisecond and the serial link is 8N1.

The list of Multiwii blocks is enumerated below:

Multiwii Connect	Connects to the auto-pilot.
Multiwii Altitude	Reads the altitude of the aircraft.
Multiwii Analog	Reads the analog sensors, such as voltage and current measurements.
Multiwii Attitude	Reads the attitude of the aircraft, including its heading.
Multiwii Bind	Binds to satellites.
Multiwii Box Identifiers	Gets the box identifiers used by the auto-pilot.
Multiwii Calibration	Calibrates auto-pilot sensors.
Multiwii Computed GPS	Gets the GPS coordinates relative to the home location.
Multiwii EEPROM Write	Writes the settings to the auto-pilot EEPROM.
Multiwii Heading Lock	Sets a new heading lock reference.
Multiwii Identity	Gets information about the auto-pilot.
Multiwii IMU	Gets raw IMU sensor data from the auto-pilot.
Multiwii Motor Pins	Gets the motor pin indications from the auto-pilot.
Multiwii Names	Gets the names of the boxes or PID items from the auto-pilot.
Multiwii Read Actuators	Reads the commands for the servos or motors from the auto-pilot.
Multiwii Read Boxes	Reads the box items from the auto-pilot. Each word in the output array is a bitmask of activation switches.
Multiwii Read GPS	Reads the raw GPS data from the auto-pilot.
Multiwii Read Miscellaneous	Reads miscellaneous information from the auto-pilot, such as thresholds, triggers and counters.
Multiwii Read PID	Reads PID gains from the auto-pilot.
Multiwii Read RC	Reads RC values from the auto-pilot.
Multiwii Read RC Tuning	Reads RC tuning parameters from the auto-pilot.
Multiwii Read Servo Configuration	Reads the servo configuration from the auto-pilot.
Multiwii Read Waypoint	Reads the current waypoint from the auto-pilot.
Multiwii Reset Configuration	Resets all parameters to defaults in the auto-pilot.
Multiwii Select Setting	Select the setting configuration for the auto-pilot.
Multiwii Status	Gets the status of the auto-pilot.
Multiwii Write Actuators	Writes the commands for the motors to the auto-pilot.
Multiwii Write Boxes	Writes box items to the auto-pilot. Each word in the input array is a bitmask of activation switches.
Multiwii Write GPS	Writes raw GPS data to the auto-pilot. The data is injected into the GPS stream.
Multiwii Write Miscellaneous	Writes miscellaneous information from the auto-pilot, such as thresholds, triggers and counters.
Multiwii Write PID	Writes PID gains to the auto-pilot.
Multiwii Write RC	Writes raw RC values to the auto-pilot.
Multiwii Write RC Tuning	Writes RC tuning parameters to the auto-pilot.
Multiwii Write Servo Configuration	Writes the servo configuration to the auto-pilot.
Multiwii Write Waypoint	Writes a new waypoint to the auto-pilot.
Multiwii Write Waypoint	Writes a new waypoint to the auto-pilot.
Multiwii Debug	Gets debug values from the auto-pilot.

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