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Software / API Bindings / MATLAB/Octave / API Reference and Examples / IP Connection

MATLAB/Octave - IP Connection

This is the description of the MATLAB/Octave API bindings for the IP Connection. The IP Connection manages the communication between the API bindings and the Brick Daemon or a WIFI/Ethernet Extension. Before Bricks and Bricklets can be controlled using their API an IP Connection has to be created and its TCP/IP connection has to be established.

An installation guide for the MATLAB/Octave API bindings is part of their general description.

Examples

The example code below is Public Domain (CC0 1.0).

Enumerate (MATLAB)

Download (matlab_example_enumerate.m)

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function matlab_example_enumerate()
    import com.tinkerforge.IPConnection;

    HOST = 'localhost';
    PORT = 4223;

    ipcon = handle(IPConnection(), 'CallbackProperties'); % Create IP connection

    ipcon.connect(HOST, PORT); % Connect to brickd

    % Register Enumerate Callback
    set(ipcon, 'EnumerateCallback', @(h, e) cb_enumerate(e));

    % Trigger Enumerate
    ipcon.enumerate();

    input('Press any key to exit...\n', 's');
    ipcon.disconnect();
end

% Print incoming enumeration
function cb_enumerate(e)
    ipcon = e.getSource();

    fprintf('UID: %s\n', char(e.uid));
    fprintf('Enumeration Type: %d\n', e.enumerationType);

    if e.enumerationType == ipcon.ENUMERATION_TYPE_DISCONNECTED
        fprintf('\n');
        return;
    end

    fprintf('Connected UID: %s\n', char(e.connectedUid));
    fprintf('Position: %s\n', e.position);
    fprintf('Hardware Version: ');
    fprintf('%d', rot90(e.hardwareVersion));
    fprintf('\n');
    fprintf('Firmware Version: ');
    fprintf('%d', rot90(e.firmwareVersion));
    fprintf('\n');
    fprintf('Device Identifier: %d\n', e.deviceIdentifier);
    fprintf('\n');
end

Authenticate (MATLAB)

Download (matlab_example_authenticate.m)

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function matlab_example_authenticate()
    import com.tinkerforge.IPConnection;

    global SECRET;

    HOST = 'localhost';
    PORT = 4223;
    SECRET = 'My Authentication Secret!';

    ipcon = handle(IPConnection(), 'CallbackProperties'); % Create IP connection

    % Disable auto reconnect mechanism, in case we have the wrong secret.
    % If the authentication is successful, reenable it.
    ipcon.setAutoReconnect(false)

    % Register Connected Callback
    set(ipcon, 'ConnectedCallback', @(h, e) cb_connected(e));

    % Register Enumerate Callback
    set(ipcon, 'EnumerateCallback', @(h, e) cb_enumerate(e));

    ipcon.connect(HOST, PORT); % Connect to brickd

    input('Press any key to exit...\n', 's');
    ipcon.disconnect();
end

% Authenticate each time the connection got (re-)established
function cb_connected(e)
    ipcon = e.getSource();

    global SECRET;

    if e.connectReason == ipcon.CONNECT_REASON_REQUEST
        fprintf('Connected by request\n');
    elseif e.connectReason == ipcon.CONNECT_REASON_AUTO_RECONNECT
        fprintf('Auto-Reconnect\n');
    end

    % Authenticate first...
    try
        ipcon.authenticate(SECRET);
        fprintf('Authentication succeeded\n');
    catch ex
        fprintf('Could not authenticate\n');
        return
    end

    % ...reenable auto reconnect mechanism, as described above...
    ipcon.setAutoReconnect(true)

    % ...then trigger enumerate
    ipcon.enumerate();
end

% Print incoming enumeration
function cb_enumerate(e)
    fprintf('UID: %s, Enumeration Type: %g\n', char(e.uid), e.enumerationType);
end

Enumerate (Octave)

Download (octave_example_enumerate.m)

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function octave_example_enumerate()
    more off;

    HOST = "localhost";
    PORT = 4223;

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection

    ipcon.connect(HOST, PORT); % Connect to brickd

    % Register Enumerate Callback
    ipcon.addEnumerateCallback(@cb_enumerate);

    % Trigger Enumerate
    ipcon.enumerate();

    input("Press any key to exit...\n", "s");
    ipcon.disconnect();
end

% Print incoming enumeration
function cb_enumerate(e)
    ipcon = e.getSource();

    fprintf("UID: %s\n", e.uid);
    fprintf("Enumeration Type: %d\n", java2int(e.enumerationType));

    if java2int(e.enumerationType) == java2int(ipcon.ENUMERATION_TYPE_DISCONNECTED)
        fprintf("\n");
        return;
    end

    hardwareVersion = e.hardwareVersion;
    firmwareVersion = e.firmwareVersion;

    fprintf("Connected UID: %s\n", e.connectedUid);
    fprintf("Position: %s\n", e.position);
    fprintf("Hardware Version: %d.%d.%d\n", java2int(hardwareVersion(1)), ...
                                            java2int(hardwareVersion(2)), ...
                                            java2int(hardwareVersion(3)));
    fprintf("Firmware Version: %d.%d.%d\n", java2int(firmwareVersion(1)), ...
                                            java2int(firmwareVersion(2)), ...
                                            java2int(firmwareVersion(3)));
    fprintf("Device Identifier: %d\n", e.deviceIdentifier);
    fprintf("\n");
end

function int = java2int(value)
    if compare_versions(version(), "3.8", "<=")
        int = value.intValue();
    else
        int = value;
    end
end

Authenticate (Octave)

Download (octave_example_authenticate.m)

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function octave_example_authenticate()
    more off;

    global SECRET;

    HOST = "localhost";
    PORT = 4223;
    SECRET = "My Authentication Secret!";

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection

    % Disable auto reconnect mechanism, in case we have the wrong secret.
    % If the authentication is successful, reenable it.
    ipcon.setAutoReconnect(false)

    % Register Connected Callback
    ipcon.addConnectedCallback(@cb_connected);

    % Register Enumerate Callback
    ipcon.addEnumerateCallback(@cb_enumerate);

    ipcon.connect(HOST, PORT); % Connect to brickd

    input("Press any key to exit...\n", "s");
    ipcon.disconnect();
end

% Authenticate each time the connection got (re-)established
function cb_connected(e)
    ipcon = e.getSource();

    global SECRET;

    if java2int(e.connectReason) == java2int(ipcon.CONNECT_REASON_REQUEST)
        fprintf("Connected by request\n");
    elseif java2int(e.connectReason) == java2int(ipcon.CONNECT_REASON_AUTO_RECONNECT)
        fprintf("Auto-Reconnect\n");
    end

    % Authenticate first...
    try
        ipcon.authenticate(SECRET);
        fprintf("Authentication succeeded\n");
    catch ex
        fprintf("Could not authenticate\n");
        return
    end

    % ...reenable auto reconnect mechanism, as described above...
    ipcon.setAutoReconnect(true)

    % ...then trigger enumerate
    ipcon.enumerate();
end

% Print incoming enumeration
function cb_enumerate(e)
    fprintf("UID: %s, Enumeration Type: %d\n", e.uid, e.enumerationType);
end

function int = java2int(value)
    if compare_versions(version(), "3.8", "<=")
        int = value.intValue();
    else
        int = value;
    end
end

API

Basic Functions

class IPConnection()

Creates an IP Connection object that can be used to enumerate the available devices. It is also required for the constructor of Bricks and Bricklets.

In MATLAB:

import com.tinkerforge.IPConnection;

ipcon = IPConnection();

In Octave:

ipcon = java_new("com.tinkerforge.IPConnection");
void IPConnection.connect(String host, int port)

Creates a TCP/IP connection to the given host and port. The host and port can refer to a Brick Daemon or to a WIFI/Ethernet Extension.

Devices can only be controlled when the connection was established successfully.

Blocks until the connection is established and throws an exception if there is no Brick Daemon or WIFI/Ethernet Extension listening at the given host and port.

void IPConnection.disconnect()

Disconnects the TCP/IP connection from the Brick Daemon or the WIFI/Ethernet Extension.

void IPConnection.authenticate(String secret)

Performs an authentication handshake with the connected Brick Daemon or WIFI/Ethernet Extension. If the handshake succeeds the connection switches from non-authenticated to authenticated state and communication can continue as normal. If the handshake fails then the connection gets closed. Authentication can fail if the wrong secret was used or if authentication is not enabled at all on the Brick Daemon or the WIFI/Ethernet Extension.

See the authentication tutorial for more information.

byte IPConnection.getConnectionState()

Can return the following states:

  • IPConnection.CONNECTION_STATE_DISCONNECTED = 0: No connection is established.
  • IPConnection.CONNECTION_STATE_CONNECTED = 1: A connection to the Brick Daemon or the WIFI/Ethernet Extension is established.
  • IPConnection.CONNECTION_STATE_PENDING = 2: IP Connection is currently trying to connect.
void IPConnection.setAutoReconnect(boolean autoReconnect)

Enables or disables auto-reconnect. If auto-reconnect is enabled, the IP Connection will try to reconnect to the previously given host and port, if the currently existing connection is lost. Therefore, auto-reconnect only does something after a successful connect() call.

Default value is true.

boolean IPConnection.getAutoReconnect()

Returns true if auto-reconnect is enabled, false otherwise.

void IPConnection.setTimeout(int timeout)

Sets the timeout in milliseconds for getters and for setters for which the response expected flag is activated.

Default timeout is 2500.

int IPConnection.getTimeout()

Returns the timeout as set by setTimeout().

void IPConnection.enumerate()

Broadcasts an enumerate request. All devices will respond with an enumerate callback.

Callbacks

Callbacks can be registered to be notified about events. The registration is done with "set" function of MATLAB. The parameters consist of the IP Connection object, the callback name and the callback function. For example, it looks like this in MATLAB:

function my_callback(e)
    fprintf('Parameter: %s\n', e.param);
end

set(ipcon, 'ExampleCallback', @(h, e) my_callback(e));

Due to a difference in the Octave Java support the "set" function cannot be used in Octave. The registration is done with "add*Callback" functions of the IP Connection object. It looks like this in Octave:

function my_callback(e)
    fprintf("Parameter: %s\n", e.param);
end

ipcon.addExampleCallback(@my_callback);

It is possible to add several callback functions and to remove them with the corresponding "remove*Callback" function.

The parameters of the callback are passed to the callback function as fields of the structure e, which is derived from the java.util.EventObject class. The available callback names with corresponding structure fields are described below.

callback IPConnection.EnumerateCallback
Parameters:
  • uid -- String
  • connectedUid -- String
  • position -- char
  • hardwareVersion -- short[]
  • firmwareVersion -- short[]
  • deviceIdentifier -- int
  • enumerationType -- short

The callback function receives seven parameters as fields of the structure e:

  • uid: The UID of the device.
  • connectedUID: UID where the device is connected to. For a Bricklet this is the UID of the Brick or Bricklet it is connected to. For a Brick it is the UID of the bottommost Brick in the stack. For the bottommost Brick in a stack it is "0". With this information it is possible to reconstruct the complete network topology.
  • position: For Bricks: '0' - '8' (position in stack). For Bricklets: 'a' - 'h' (position on Brick) or 'i' (position of the Raspberry Pi (Zero) HAT) or 'z' (Bricklet on Isolator Bricklet).
  • hardwareVersion: Major, minor and release number for hardware version.
  • firmwareVersion: Major, minor and release number for firmware version.
  • deviceIdentifier: A number that represents the device.
  • enumerationType: Type of enumeration.

Possible enumeration types are:

  • IPConnection.ENUMERATION_TYPE_AVAILABLE = 0: Device is available (enumeration triggered by user: enumerate()). This enumeration type can occur multiple times for the same device.
  • IPConnection.ENUMERATION_TYPE_CONNECTED = 1: Device is newly connected (automatically send by Brick after establishing a communication connection). This indicates that the device has potentially lost its previous configuration and needs to be reconfigured.
  • IPConnection.ENUMERATION_TYPE_DISCONNECTED = 2: Device is disconnected (only possible for USB connection). In this case only uid and enumerationType are valid.

It should be possible to implement plug-and-play functionality with this (as is done in Brick Viewer).

The device identifier numbers can be found here. There are also constants for these numbers named following this pattern:

<device-class>.DEVICE_IDENTIFIER

For example: BrickMaster.DEVICE_IDENTIFIER or BrickletAmbientLight.DEVICE_IDENTIFIER.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addEnumerateCallback() function. An added callback function can be removed with the removeEnumerateCallback() function.

callback IPConnection.ConnectedCallback
Parameters:connectReason -- short

This callback is called whenever the IP Connection got connected to a Brick Daemon or to a WIFI/Ethernet Extension, possible reasons are:

  • IPConnection.CONNECT_REASON_REQUEST = 0: Connection established after request from user.
  • IPConnection.CONNECT_REASON_AUTO_RECONNECT = 1: Connection after auto-reconnect.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addConnectedCallback() function. An added callback function can be removed with the removeConnectedCallback() function.

callback IPConnection.DisconnectedCallback
Parameters:disconnectReason -- short

This callback is called whenever the IP Connection got disconnected from a Brick Daemon or from a WIFI/Ethernet Extension, possible reasons are:

  • IPConnection.DISCONNECT_REASON_REQUEST = 0: Disconnect was requested by user.
  • IPConnection.DISCONNECT_REASON_ERROR = 1: Disconnect because of an unresolvable error.
  • IPConnection.DISCONNECT_REASON_SHUTDOWN = 2: Disconnect initiated by Brick Daemon or WIFI/Ethernet Extension.

In MATLAB the set() function can be used to register a callback function to this callback.

In Octave a callback function can be added to this callback using the addDisconnectedCallback() function. An added callback function can be removed with the removeDisconnectedCallback() function.