Java - IO-4 Bricklet

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

An installation guide for the Java API bindings is part of their general description.

Examples

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

Input

Download (ExampleInput.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletIO4;

public class ExampleInput {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your IO-4 Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletIO4 io = new BrickletIO4(UID, ipcon); // Create device object

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

        // Get current value as bitmask
        short valueMask = io.getValue(); // Can throw com.tinkerforge.TimeoutException
        System.out.println("Value Mask: " + Integer.toBinaryString(valueMask));

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Output

Download (ExampleOutput.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletIO4;

public class ExampleOutput {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your IO-4 Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletIO4 io = new BrickletIO4(UID, ipcon); // Create device object

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

        // Set pin 1 to output low
        io.setConfiguration((short)(1 << 1), 'o', false);

        // Set pin 2 and 3 to output high
        io.setConfiguration((short)((1 << 2) | (1 << 3)), 'o', true);

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

Interrupt

Download (ExampleInterrupt.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletIO4;

public class ExampleInterrupt {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your IO-4 Bricklet
    private static final String UID = "XYZ";

    // Note: To make the example code cleaner we do not handle exceptions. Exceptions
    //       you might normally want to catch are described in the documentation
    public static void main(String args[]) throws Exception {
        IPConnection ipcon = new IPConnection(); // Create IP connection
        BrickletIO4 io = new BrickletIO4(UID, ipcon); // Create device object

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

        // Add interrupt listener
        io.addInterruptListener(new BrickletIO4.InterruptListener() {
            public void interrupt(short interruptMask, short valueMask) {
                System.out.println("Interrupt Mask: " + Integer.toBinaryString(interruptMask));
                System.out.println("Value Mask: " + Integer.toBinaryString(valueMask));
                System.out.println("");
            }
        });

        // Enable interrupt on pin 0
        io.setInterrupt((short)(1 << 0));

        System.out.println("Press key to exit"); System.in.read();
        ipcon.disconnect();
    }
}

API

Generally, every method of the Java 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 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

class BrickletIO4(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletIO4 io4 = new BrickletIO4("YOUR_DEVICE_UID", ipcon);

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

void BrickletIO4.setValue(short valueMask)

Sets the output value (high or low) with a bitmask (4bit). A 1 in the bitmask means high and a 0 in the bitmask means low.

For example: The value 3 or 0b0011 will turn the pins 0-1 high and the pins 2-3 low.

All running monoflop timers will be aborted if this function is called.

Note

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

short BrickletIO4.getValue()

Returns a bitmask of the values that are currently measured. This function works if the pin is configured to input as well as if it is configured to output.

void BrickletIO4.setConfiguration(short selectionMask, char direction, boolean value)

Configures the value and direction of the specified pins. 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:

  • (15, 'i', true) or (0b1111, 'i', true) will set all pins of as input pull-up.
  • (8, 'i', false) or (0b1000, 'i', false) will set pin 3 of as input default (floating if nothing is connected).
  • (3, 'o', false) or (0b0011, 'o', false) will set pins 0 and 1 as output low.
  • (4, 'o', true) or (0b0100, 'o', true) will set pin 2 of as output high.

Running monoflop timers for the specified pins will be aborted if this function is called.

The default configuration is input with pull-up.

The following constants are available for this function:

  • BrickletIO4.DIRECTION_IN = 'i'
  • BrickletIO4.DIRECTION_OUT = 'o'
BrickletIO4.Configuration BrickletIO4.getConfiguration()

Returns a value bitmask and a direction bitmask. A 1 in the direction bitmask means input and a 0 in the bitmask means output.

For example: A return value of (3, 5) or (0b0011, 0b0101) for direction and value means that:

  • pin 0 is configured as input pull-up,
  • pin 1 is configured as input default,
  • pin 2 is configured as output high and
  • pin 3 is are configured as output low.

The returned object has the public member variables short directionMask and short valueMask.

long BrickletIO4.getEdgeCount(short pin, boolean resetCounter)

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

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

New in version 2.0.1 (Plugin).

Advanced Functions

void BrickletIO4.setMonoflop(short selectionMask, short valueMask, long time)

Configures a monoflop of the pins specified by the first parameter as 4 bit long bitmask. The specified pins must be configured for output. Non-output pins will be ignored.

The second parameter is a bitmask with the desired value of the specified output pins. A 1 in the bitmask means high and a 0 in the bitmask means low.

The third parameter indicates the time (in ms) that the pins should hold the value.

If this function is called with the parameters (9, 1, 1500) or (0b1001, 0b0001, 1500): Pin 0 will get high and pin 3 will get low. In 1.5s pin 0 will get low and pin 3 will get high again.

A monoflop can be used as a fail-safe mechanism. For example: Lets assume you have a RS485 bus and an IO-4 Bricklet connected to one of the slave stacks. You can now call this function every second, with a time parameter of two seconds and pin 0 set to high. Pin 0 will be high all the time. If now the RS485 connection is lost, then pin 0 will get low in at most two seconds.

BrickletIO4.Monoflop BrickletIO4.getMonoflop(short pin)

Returns (for the given pin) 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 short value, long time and long timeRemaining.

void BrickletIO4.setSelectedValues(short selectionMask, short valueMask)

Sets the output value (high or low) with a bitmask, according to the selection mask. The bitmask is 4 bit long, true refers to high and false refers to low.

For example: The parameters (9, 4) or (0b0110, 0b0100) will turn pin 1 low and pin 2 high, pin 0 and 3 will remain untouched.

Running monoflop timers for the selected pins will be aborted if this function is called.

Note

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

void BrickletIO4.setEdgeCountConfig(short selectionMask, short edgeType, short debounce)

Configures the edge counter for the selected pins.

The edge type parameter configures if rising edges, falling edges or both are counted if the pin 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:

  • BrickletIO4.EDGE_TYPE_RISING = 0
  • BrickletIO4.EDGE_TYPE_FALLING = 1
  • BrickletIO4.EDGE_TYPE_BOTH = 2

New in version 2.0.1 (Plugin).

BrickletIO4.EdgeCountConfig BrickletIO4.getEdgeCountConfig(short pin)

Returns the edge type and debounce time for the selected pin as set by setEdgeCountConfig().

The following constants are available for this function:

  • BrickletIO4.EDGE_TYPE_RISING = 0
  • BrickletIO4.EDGE_TYPE_FALLING = 1
  • BrickletIO4.EDGE_TYPE_BOTH = 2

New in version 2.0.1 (Plugin).

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

short[] BrickletIO4.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.

boolean BrickletIO4.getResponseExpected(short 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 listener 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.

The following constants are available for this function:

  • BrickletIO4.FUNCTION_SET_VALUE = 1
  • BrickletIO4.FUNCTION_SET_CONFIGURATION = 3
  • BrickletIO4.FUNCTION_SET_DEBOUNCE_PERIOD = 5
  • BrickletIO4.FUNCTION_SET_INTERRUPT = 7
  • BrickletIO4.FUNCTION_SET_MONOFLOP = 10
  • BrickletIO4.FUNCTION_SET_SELECTED_VALUES = 13
  • BrickletIO4.FUNCTION_SET_EDGE_COUNT_CONFIG = 15
void BrickletIO4.setResponseExpected(short 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 listener 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 constants are available for this function:

  • BrickletIO4.FUNCTION_SET_VALUE = 1
  • BrickletIO4.FUNCTION_SET_CONFIGURATION = 3
  • BrickletIO4.FUNCTION_SET_DEBOUNCE_PERIOD = 5
  • BrickletIO4.FUNCTION_SET_INTERRUPT = 7
  • BrickletIO4.FUNCTION_SET_MONOFLOP = 10
  • BrickletIO4.FUNCTION_SET_SELECTED_VALUES = 13
  • BrickletIO4.FUNCTION_SET_EDGE_COUNT_CONFIG = 15
void BrickletIO4.setResponseExpectedAll(boolean responseExpected)

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

BrickletIO4.Identity BrickletIO4.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, short[] hardwareVersion, short[] firmwareVersion and int deviceIdentifier.

Listener Configuration Functions

void BrickletIO4.setDebouncePeriod(long debounce)

Sets the debounce period of the InterruptListener listener in ms.

For example: If you set this value to 100, you will get the interrupt maximal every 100ms. This is necessary if something that bounces is connected to the IO-4 Bricklet, such as a button.

The default value is 100.

long BrickletIO4.getDebouncePeriod()

Returns the debounce period as set by setDebouncePeriod().

void BrickletIO4.setInterrupt(short interruptMask)

Sets the pins on which an interrupt is activated with a bitmask. Interrupts are triggered on changes of the voltage level of the pin, i.e. changes from high to low and low to high.

For example: An interrupt bitmask of 10 or 0b1010 will enable the interrupt for pins 1 and 3.

The interrupt is delivered with the InterruptListener listener.

short BrickletIO4.getInterrupt()

Returns the interrupt bitmask as set by setInterrupt().

Listeners

Listeners can be registered to receive time critical or recurring data from the device. The registration is done with add*Listener() functions of the device object.

The parameter is a listener class object, for example:

device.addExampleListener(new BrickletIO4.ExampleListener() {
    public void property(int value) {
        System.out.println("Value: " + value);
    }
});

The available listener classes with inherent methods to be overwritten are described below. It is possible to add several listeners and to remove them with the corresponding remove*Listener() function.

Note

Using listeners 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.

class BrickletIO4.InterruptListener()

This listener can be added with the addInterruptListener() function. An added listener can be removed with the removeInterruptListener() function.

void interrupt(short interruptMask, short valueMask)

This listener is triggered whenever a change of the voltage level is detected on pins where the interrupt was activated with setInterrupt().

The values are a bitmask that specifies which interrupts occurred and the current value bitmask.

For example:

  • (1, 1) or (0b0001, 0b0001) means that an interrupt on pin 0 occurred and currently pin 0 is high and pins 1-3 are low.
  • (9, 14) or (0b1001, 0b1110) means that interrupts on pins 0 and 3 occurred and currently pin 0 is low and pins 1-3 are high.
class BrickletIO4.MonoflopDoneListener()

This listener can be added with the addMonoflopDoneListener() function. An added listener can be removed with the removeMonoflopDoneListener() function.

void monoflopDone(short selectionMask, short valueMask)

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

Constants

static final int BrickletIO4.DEVICE_IDENTIFIER

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

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

static final String BrickletIO4.DEVICE_DISPLAY_NAME

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