MATLAB/Octave - IO-4 Bricklet 2.0

This is the description of the MATLAB/Octave API bindings for the IO-4 Bricklet 2.0. General information and technical specifications for the IO-4 Bricklet 2.0 are summarized in its hardware description.

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).

Output (MATLAB)

Download (matlab_example_output.m)

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function matlab_example_output()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletIO4V2;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your IO-4 Bricklet 2.0

    ipcon = IPConnection(); % Create IP connection
    io = handle(BrickletIO4V2(UID, ipcon), 'CallbackProperties'); % Create device object

    ipcon.connect(HOST, PORT); % Connect to brickd
    % Don't use device before ipcon is connected

    % Configure channel 3 as output low
    io.setConfiguration(3, 'o', false);

    % Set channel 3 alternating high/low 10 times with 100 ms delay
    for i = 0:9
        pause(0.1);
        io.setSelectedValue(3, true);
        pause(0.1);
        io.setSelectedValue(3, false);
    end

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

Interrupt (MATLAB)

Download (matlab_example_interrupt.m)

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function matlab_example_interrupt()
    import com.tinkerforge.IPConnection;
    import com.tinkerforge.BrickletIO4V2;

    HOST = 'localhost';
    PORT = 4223;
    UID = 'XYZ'; % Change XYZ to the UID of your IO-4 Bricklet 2.0

    ipcon = IPConnection(); % Create IP connection
    io = handle(BrickletIO4V2(UID, ipcon), 'CallbackProperties'); % Create device object

    ipcon.connect(HOST, PORT); % Connect to brickd
    % Don't use device before ipcon is connected

    % Register input value callback to function cb_input_value
    set(io, 'InputValueCallback', @(h, e) cb_input_value(e));

    % Set period for input value (channel 1) callback to 0.5s (500ms)
    io.setInputValueCallbackConfiguration(1, 500, false);

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

% Callback function for input value callback
function cb_input_value(e)
    fprintf('Channel: %i\n', e.channel);
    fprintf('Changed: %i\n', e.changed);
    fprintf('Value: %i\n', e.value);
    fprintf('\n');
end

Output (Octave)

Download (octave_example_output.m)

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function octave_example_output()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your IO-4 Bricklet 2.0

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    io = javaObject("com.tinkerforge.BrickletIO4V2", UID, ipcon); % Create device object

    ipcon.connect(HOST, PORT); % Connect to brickd
    % Don't use device before ipcon is connected

    % Configure channel 3 as output low
    io.setConfiguration(3, "o", false);

    % Set channel 3 alternating high/low 10 times with 100 ms delay
    for i = 0:9
        pause(0.1);
        io.setSelectedValue(3, true);
        pause(0.1);
        io.setSelectedValue(3, false);
    end

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

Interrupt (Octave)

Download (octave_example_interrupt.m)

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function octave_example_interrupt()
    more off;

    HOST = "localhost";
    PORT = 4223;
    UID = "XYZ"; % Change XYZ to the UID of your IO-4 Bricklet 2.0

    ipcon = javaObject("com.tinkerforge.IPConnection"); % Create IP connection
    io = javaObject("com.tinkerforge.BrickletIO4V2", UID, ipcon); % Create device object

    ipcon.connect(HOST, PORT); % Connect to brickd
    % Don't use device before ipcon is connected

    % Register input value callback to function cb_input_value
    io.addInputValueCallback(@cb_input_value);

    % Set period for input value (channel 1) callback to 0.5s (500ms)
    io.setInputValueCallbackConfiguration(1, 500, false);

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

% Callback function for input value callback
function cb_input_value(e)
    fprintf("Channel: %d\n", e.channel);
    fprintf("Changed: %d\n", e.changed);
    fprintf("Value: %d\n", e.value);
    fprintf("\n");
end

API

Generally, every method of the MATLAB bindings that returns a value can throw a TimeoutException. This exception gets thrown if the device did not respond. If a cable based connection is used, it is unlikely that this exception gets thrown (assuming nobody unplugs the device). However, if a wireless connection is used, timeouts will occur if the distance to the device gets too big.

Beside the TimeoutException there is also a NotConnectedException that is thrown if a method needs to communicate with the device while the IP Connection is not connected.

Since the MATLAB bindings are based on Java and Java does not support multiple return values and return by reference is not possible for primitive types, we use small classes that only consist of member variables. The member variables of the returned objects are described in the corresponding method descriptions.

The package for all Brick/Bricklet bindings and the IP Connection is com.tinkerforge.*

All methods listed below are thread-safe.

Basic Functions

public class BrickletIO4V2(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid.

In MATLAB:

import com.tinkerforge.BrickletIO4V2;

io4V2 = BrickletIO4V2('YOUR_DEVICE_UID', ipcon);

In Octave:

io4V2 = java_new("com.tinkerforge.BrickletIO4V2", "YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected (see examples above).

public void setValue(boolean[] value)

Sets the output value of all four channels. A value of true or false outputs logic 1 or logic 0 respectively on the corresponding channel.

Use setSelectedValue() to change only one output channel state.

For example: (True, True, False, False) will turn the channels 0-1 high and the channels 2-3 low.

Note

This function does nothing for channels that are configured as input. Pull-up resistors can be switched on with setConfiguration().

public boolean[] getValue()

Returns the logic levels that are currently measured on the channels. This function works if the channel is configured as input as well as if it is configured as output.

public void setSelectedValue(int channel, boolean value)

Sets the output value of a specific channel without affecting the other channels.

Note

This function does nothing for channels that are configured as input. Pull-up resistors can be switched on with setConfiguration().

public void setConfiguration(int channel, char direction, boolean value)

Configures the value and direction of a specific channel. Possible directions are 'i' and 'o' for input and output.

If the direction is configured as output, the value is either high or low (set as true or false).

If the direction is configured as input, the value is either pull-up or default (set as true or false).

For example:

  • (0, 'i', true) will set channel 0 as input pull-up.
  • (1, 'i', false) will set channel 1 as input default (floating if nothing is connected).
  • (2, 'o', true) will set channel 2 as output high.
  • (3, 'o', false) will set channel 3 as output low.

The default configuration is input with pull-up.

The following constants are available for this function:

  • BrickletIO4V2.DIRECTION_IN = 'i'
  • BrickletIO4V2.DIRECTION_OUT = 'o'

Advanced Functions

public void setMonoflop(int channel, boolean value, long time)

The first parameter is the desired state of the channel (true means output high and false means output low). The second parameter indicates the time (in ms) that the channel should hold the state.

If this function is called with the parameters (true, 1500): The channel will turn on and in 1.5s it will turn off again.

A monoflop can be used as a failsafe mechanism. For example: Lets assume you have a RS485 bus and a IO-4 Bricklet 2.0 is connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds. The channel will be high all the time. If now the RS485 connection is lost, the channel will turn low in at most two seconds.

public BrickletIO4V2.Monoflop getMonoflop(int channel)

Returns (for the given channel) the current value and the time as set by setMonoflop() as well as the remaining time until the value flips.

If the timer is not running currently, the remaining time will be returned as 0.

The returned object has the public member variables boolean value, long time and long timeRemaining.

public long getEdgeCount(int channel, boolean resetCounter)

Returns the current value of the edge counter for the selected channel. You can configure the edges that are counted with setEdgeCountConfiguration().

If you set the reset counter to true, the count is set back to 0 directly after it is read.

public void setEdgeCountConfiguration(int channel, int edgeType, int debounce)

Configures the edge counter for a specific channel.

The edge type parameter configures if rising edges, falling edges or both are counted if the channel is configured for input. Possible edge types are:

  • 0 = rising (default)
  • 1 = falling
  • 2 = both

The debounce time is given in ms.

Configuring an edge counter resets its value to 0.

If you don't know what any of this means, just leave it at default. The default configuration is very likely OK for you.

Default values: 0 (edge type) and 100ms (debounce time)

The following constants are available for this function:

  • BrickletIO4V2.EDGE_TYPE_RISING = 0
  • BrickletIO4V2.EDGE_TYPE_FALLING = 1
  • BrickletIO4V2.EDGE_TYPE_BOTH = 2
public BrickletIO4V2.EdgeCountConfiguration getEdgeCountConfiguration(int channel)

Returns the edge type and debounce time for the selected channel as set by setEdgeCountConfiguration().

The following constants are available for this function:

  • BrickletIO4V2.EDGE_TYPE_RISING = 0
  • BrickletIO4V2.EDGE_TYPE_FALLING = 1
  • BrickletIO4V2.EDGE_TYPE_BOTH = 2

The returned object has the public member variables int edgeType and int debounce.

public void setPWMConfiguration(int channel, long frequency, int dutyCycle)

Activates a PWM for the given channel with the frequency given in 1/10Hz and the duty cycle given in 1/100%.

You need to set the channel to output before you call this function, otherwise it will be ignored. To turn the PWM off again, you can set the frequency to 0 or any other function that changes a value of the channel (e.g. setSelectedValue()).

The maximum frequency value is 320000000 (32MHz). The maximum duty cycle value is 10000 (100%).

The default values are 0, 0.

public BrickletIO4V2.PWMConfiguration getPWMConfiguration(int channel)

Returns the PWM configuration as set by setPWMConfiguration().

The returned object has the public member variables long frequency and int dutyCycle.

public int[] getAPIVersion()

Returns the version of the API definition (major, minor, revision) implemented by this API bindings. This is neither the release version of this API bindings nor does it tell you anything about the represented Brick or Bricklet.

public boolean getResponseExpected(int functionId)

Returns the response expected flag for the function specified by the function ID parameter. It is true if the function is expected to send a response, false otherwise.

For getter functions this is enabled by default and cannot be disabled, because those functions will always send a response. For callback configuration functions it is enabled by default too, but can be disabled by setResponseExpected(). For setter functions it is disabled by default and can be enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

See setResponseExpected() for the list of function ID constants available for this function.

public void setResponseExpected(int functionId, boolean responseExpected)

Changes the response expected flag of the function specified by the function ID parameter. This flag can only be changed for setter (default value: false) and callback configuration functions (default value: true). For getter functions it is always enabled.

Enabling the response expected flag for a setter function allows to detect timeouts and other error conditions calls of this setter as well. The device will then send a response for this purpose. If this flag is disabled for a setter function then no response is send and errors are silently ignored, because they cannot be detected.

The following function ID constants are available for this function:

  • BrickletIO4V2.FUNCTION_SET_VALUE = 1
  • BrickletIO4V2.FUNCTION_SET_SELECTED_VALUE = 3
  • BrickletIO4V2.FUNCTION_SET_CONFIGURATION = 4
  • BrickletIO4V2.FUNCTION_SET_INPUT_VALUE_CALLBACK_CONFIGURATION = 6
  • BrickletIO4V2.FUNCTION_SET_ALL_INPUT_VALUE_CALLBACK_CONFIGURATION = 8
  • BrickletIO4V2.FUNCTION_SET_MONOFLOP = 10
  • BrickletIO4V2.FUNCTION_SET_EDGE_COUNT_CONFIGURATION = 13
  • BrickletIO4V2.FUNCTION_SET_PWM_CONFIGURATION = 15
  • BrickletIO4V2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletIO4V2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletIO4V2.FUNCTION_RESET = 243
  • BrickletIO4V2.FUNCTION_WRITE_UID = 248
public void setResponseExpectedAll(boolean responseExpected)

Changes the response expected flag for all setter and callback configuration functions of this device at once.

public BrickletIO4V2.SPITFPErrorCount getSPITFPErrorCount()

Returns the error count for the communication between Brick and Bricklet.

The errors are divided into

  • ACK checksum errors,
  • message checksum errors,
  • framing errors and
  • overflow errors.

The errors counts are for errors that occur on the Bricklet side. All Bricks have a similar function that returns the errors on the Brick side.

The returned object has the public member variables long errorCountAckChecksum, long errorCountMessageChecksum, long errorCountFrame and long errorCountOverflow.

public int setBootloaderMode(int mode)

Sets the bootloader mode and returns the status after the requested mode change was instigated.

You can change from bootloader mode to firmware mode and vice versa. A change from bootloader mode to firmware mode will only take place if the entry function, device identifier and CRC are present and correct.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

The following constants are available for this function:

  • BrickletIO4V2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletIO4V2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletIO4V2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletIO4V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletIO4V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletIO4V2.BOOTLOADER_STATUS_OK = 0
  • BrickletIO4V2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletIO4V2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletIO4V2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletIO4V2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletIO4V2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletIO4V2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletIO4V2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletIO4V2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletIO4V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletIO4V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
public void setWriteFirmwarePointer(long pointer)

Sets the firmware pointer for writeFirmware(). The pointer has to be increased by chunks of size 64. The data is written to flash every 4 chunks (which equals to one page of size 256).

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public int writeFirmware(int[] data)

Writes 64 Bytes of firmware at the position as written by setWriteFirmwarePointer() before. The firmware is written to flash every 4 chunks.

You can only write firmware in bootloader mode.

This function is used by Brick Viewer during flashing. It should not be necessary to call it in a normal user program.

public void setStatusLEDConfig(int config)

Sets the status LED configuration. By default the LED shows communication traffic between Brick and Bricklet, it flickers once for every 10 received data packets.

You can also turn the LED permanently on/off or show a heartbeat.

If the Bricklet is in bootloader mode, the LED is will show heartbeat by default.

The following constants are available for this function:

  • BrickletIO4V2.STATUS_LED_CONFIG_OFF = 0
  • BrickletIO4V2.STATUS_LED_CONFIG_ON = 1
  • BrickletIO4V2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletIO4V2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletIO4V2.STATUS_LED_CONFIG_OFF = 0
  • BrickletIO4V2.STATUS_LED_CONFIG_ON = 1
  • BrickletIO4V2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletIO4V2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getChipTemperature()

Returns the temperature in °C as measured inside the microcontroller. The value returned is not the ambient temperature!

The temperature is only proportional to the real temperature and it has bad accuracy. Practically it is only useful as an indicator for temperature changes.

public void reset()

Calling this function will reset the Bricklet. All configurations will be lost.

After a reset you have to create new device objects, calling functions on the existing ones will result in undefined behavior!

public void writeUID(long uid)

Writes a new UID into flash. If you want to set a new UID you have to decode the Base58 encoded UID string into an integer first.

We recommend that you use Brick Viewer to change the UID.

public long readUID()

Returns the current UID as an integer. Encode as Base58 to get the usual string version.

public BrickletIO4V2.Identity getIdentity()

Returns the UID, the UID where the Bricklet is connected to, the position, the hardware and firmware version as well as the device identifier.

The position can be 'a', 'b', 'c' or 'd'.

The device identifier numbers can be found here. There is also a constant for the device identifier of this Bricklet.

The returned object has the public member variables String uid, String connectedUid, char position, int[] hardwareVersion, int[] firmwareVersion and int deviceIdentifier.

Callback Configuration Functions

public BrickletIO4V2.Configuration getConfiguration(int channel)

Returns the channel configuration as set by setConfiguration().

The following constants are available for this function:

  • BrickletIO4V2.DIRECTION_IN = 'i'
  • BrickletIO4V2.DIRECTION_OUT = 'o'

The returned object has the public member variables char direction and boolean value.

public void setInputValueCallbackConfiguration(int channel, long period, boolean valueHasToChange)

This callback can be configured per channel.

The period in ms is the period with which the InputValueCallback callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

public BrickletIO4V2.InputValueCallbackConfiguration getInputValueCallbackConfiguration(int channel)

Returns the callback configuration for the given channel as set by setInputValueCallbackConfiguration().

The returned object has the public member variables long period and boolean valueHasToChange.

public void setAllInputValueCallbackConfiguration(long period, boolean valueHasToChange)

The period in ms is the period with which the AllInputValueCallback callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

public BrickletIO4V2.AllInputValueCallbackConfiguration getAllInputValueCallbackConfiguration()

Returns the callback configuration as set by setAllInputValueCallbackConfiguration().

The returned object has the public member variables long period and boolean valueHasToChange.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. 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(device, '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 device object. It looks like this in Octave:

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

device.addExampleCallback(@my_callback);

It is possible to add several callbacks 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.

Note

Using callbacks for recurring events is always preferred compared to using getters. It will use less USB bandwidth and the latency will be a lot better, since there is no round trip time.

public callback BrickletIO4V2.InputValueCallback
Parameters:
  • channel -- int
  • changed -- boolean
  • value -- boolean

This callback is triggered periodically according to the configuration set by setInputValueCallbackConfiguration().

The parameters are the channel, a value-changed indicator and the actual value for the channel. The changed parameter is true if the value has changed since the last callback.

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 addInputValueCallback() function. An added callback function can be removed with the removeInputValueCallback() function.

public callback BrickletIO4V2.AllInputValueCallback
Parameters:
  • changed -- boolean[]
  • value -- boolean[]

This callback is triggered periodically according to the configuration set by setAllInputValueCallbackConfiguration().

The parameters are the same as getValue(). Additional the changed parameter is true if the value has changed since the last callback.

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 addAllInputValueCallback() function. An added callback function can be removed with the removeAllInputValueCallback() function.

public callback BrickletIO4V2.MonoflopDoneCallback
Parameters:
  • channel -- int
  • value -- boolean

This callback is triggered whenever a monoflop timer reaches 0. The parameters contain the channel and the current value of the channel (the value after the monoflop).

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 addMonoflopDoneCallback() function. An added callback function can be removed with the removeMonoflopDoneCallback() function.

Constants

public static final int BrickletIO4V2.DEVICE_IDENTIFIER

This constant is used to identify a IO-4 Bricklet 2.0.

The getIdentity() function and the EnumerateCallback callback of the IP Connection have a deviceIdentifier parameter to specify the Brick's or Bricklet's type.

public static final String BrickletIO4V2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a IO-4 Bricklet 2.0.