Java - LED Strip Bricklet 2.0

This is the description of the Java API bindings for the LED Strip Bricklet 2.0. General information and technical specifications for the LED Strip Bricklet 2.0 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).

Simple

Download (ExampleSimple.java)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletLEDStripV2;

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

    // Change XYZ to the UID of your LED Strip Bricklet 2.0
    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
        BrickletLEDStripV2 ls = new BrickletLEDStripV2(UID, ipcon); // Create device object

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

        // Set first 3 LEDs to red, green and blue
        ls.setLEDValues(0, new int[]{255, 0, 0, 0, 255, 0, 0, 0, 255});

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

Callback

Download (ExampleCallback.java)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletLEDStripV2;

// FIXME: This example is incomplete

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

    // Change XYZ to the UID of your LED Strip Bricklet 2.0
    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
        BrickletLEDStripV2 ls = new BrickletLEDStripV2(UID, ipcon); // Create device object

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

        // Set frame duration to 50ms (20 frames per second)
        ls.setFrameDuration(50);

        // Use frame started callback to move the active LED every frame
        ls.addFrameStartedListener(new BrickletLEDStripV2.FrameStartedListener() {
            public void frameStarted(int length) {
                System.out.println("Length: " + length);
            }
        });

        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

public class BrickletLEDStripV2(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletLEDStripV2 ledStripV2 = new BrickletLEDStripV2("YOUR_DEVICE_UID", ipcon);

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

public void setLEDValues(int index, int[] value)

Sets the RGB(W) values for the LEDs starting from index. You can set at most 2048 RGB values or 1536 RGBW values.

To make the colors show correctly you need to configure the chip type (see setChipType()) and a channel mapping (see setChannelMapping()) according to the connected LEDs.

If the channel mapping has 3 colors, you need to give the data in the sequence RGBRGBRGB... if the channel mapping has 4 colors you need to give data in the sequence RGBWRGBWRGBW...

The data is double buffered and the colors will be transfered to the LEDs when the next frame duration ends (see setFrameDuration()).

Generic approach:

  • Set the frame duration to a value that represents the number of frames per second you want to achieve.
  • Set all of the LED colors for one frame.
  • Wait for the FrameStartedListener listener.
  • Set all of the LED colors for next frame.
  • Wait for the FrameStartedListener listener.
  • And so on.

This approach ensures that you can change the LED colors with a fixed frame rate.

public int[] getLEDValues(int index, int length)

Returns the RGB(W) values as set by setLEDValues().

public void setFrameDuration(int duration)

Sets the frame duration in ms.

Example: If you want to achieve 20 frames per second, you should set the frame duration to 50ms (50ms * 20 = 1 second).

For an explanation of the general approach see setLEDValues().

Default value: 100ms (10 frames per second).

public int getFrameDuration()

Returns the frame duration in ms as set by setFrameDuration().

public int getSupplyVoltage()

Returns the current supply voltage of the LEDs. The voltage is given in mV.

public void setClockFrequency(long frequency)

Sets the frequency of the clock in Hz. The range is 10000Hz (10kHz) up to 2000000Hz (2MHz).

The Bricklet will choose the nearest achievable frequency, which may be off by a few Hz. You can get the exact frequency that is used by calling getClockFrequency().

If you have problems with flickering LEDs, they may be bits flipping. You can fix this by either making the connection between the LEDs and the Bricklet shorter or by reducing the frequency.

With a decreasing frequency your maximum frames per second will decrease too.

The default value is 1.66MHz.

public long getClockFrequency()

Returns the currently used clock frequency as set by setClockFrequency().

public void setChipType(int chip)

Sets the type of the LED driver chip. We currently support the chips

  • WS2801,
  • WS2811,
  • WS2812 / SK6812 / NeoPixel RGB,
  • SK6812RGBW / NeoPixel RGBW (Chip Type = WS2812),
  • LPD8806 and
  • APA102 / DotStar.

The default value is WS2801 (2801).

The following constants are available for this function:

  • BrickletLEDStripV2.CHIP_TYPE_WS2801 = 2801
  • BrickletLEDStripV2.CHIP_TYPE_WS2811 = 2811
  • BrickletLEDStripV2.CHIP_TYPE_WS2812 = 2812
  • BrickletLEDStripV2.CHIP_TYPE_LPD8806 = 8806
  • BrickletLEDStripV2.CHIP_TYPE_APA102 = 102
public int getChipType()

Returns the currently used chip type as set by setChipType().

The following constants are available for this function:

  • BrickletLEDStripV2.CHIP_TYPE_WS2801 = 2801
  • BrickletLEDStripV2.CHIP_TYPE_WS2811 = 2811
  • BrickletLEDStripV2.CHIP_TYPE_WS2812 = 2812
  • BrickletLEDStripV2.CHIP_TYPE_LPD8806 = 8806
  • BrickletLEDStripV2.CHIP_TYPE_APA102 = 102
public void setChannelMapping(int mapping)

Sets the channel mapping for the connected LEDs.

If the mapping has 4 colors, the function setLEDValues() expects 4 values per pixel and if the mapping has 3 colors it expects 3 values per pixel.

The function always expects the order RGB(W). The connected LED driver chips might have their 3 or 4 channels in a different order. For example, the WS2801 chips typically use BGR order, then WS2812 chips typically use GRB order and the APA102 chips typically use WBGR order.

The APA102 chips are special. They have three 8-bit channels for RGB and an additional 5-bit channel for the overall brightness of the RGB LED making them 4-channel chips. Internally the brightness channel is the first channel, therefore one of the Wxyz channel mappings should be used. Then the W channel controls the brightness.

The default value is BGR (36).

The following constants are available for this function:

  • BrickletLEDStripV2.CHANNEL_MAPPING_RGB = 6
  • BrickletLEDStripV2.CHANNEL_MAPPING_RBG = 9
  • BrickletLEDStripV2.CHANNEL_MAPPING_BRG = 33
  • BrickletLEDStripV2.CHANNEL_MAPPING_BGR = 36
  • BrickletLEDStripV2.CHANNEL_MAPPING_GRB = 18
  • BrickletLEDStripV2.CHANNEL_MAPPING_GBR = 24
  • BrickletLEDStripV2.CHANNEL_MAPPING_RGBW = 27
  • BrickletLEDStripV2.CHANNEL_MAPPING_RGWB = 30
  • BrickletLEDStripV2.CHANNEL_MAPPING_RBGW = 39
  • BrickletLEDStripV2.CHANNEL_MAPPING_RBWG = 45
  • BrickletLEDStripV2.CHANNEL_MAPPING_RWGB = 54
  • BrickletLEDStripV2.CHANNEL_MAPPING_RWBG = 57
  • BrickletLEDStripV2.CHANNEL_MAPPING_GRWB = 78
  • BrickletLEDStripV2.CHANNEL_MAPPING_GRBW = 75
  • BrickletLEDStripV2.CHANNEL_MAPPING_GBWR = 108
  • BrickletLEDStripV2.CHANNEL_MAPPING_GBRW = 99
  • BrickletLEDStripV2.CHANNEL_MAPPING_GWBR = 120
  • BrickletLEDStripV2.CHANNEL_MAPPING_GWRB = 114
  • BrickletLEDStripV2.CHANNEL_MAPPING_BRGW = 135
  • BrickletLEDStripV2.CHANNEL_MAPPING_BRWG = 141
  • BrickletLEDStripV2.CHANNEL_MAPPING_BGRW = 147
  • BrickletLEDStripV2.CHANNEL_MAPPING_BGWR = 156
  • BrickletLEDStripV2.CHANNEL_MAPPING_BWRG = 177
  • BrickletLEDStripV2.CHANNEL_MAPPING_BWGR = 180
  • BrickletLEDStripV2.CHANNEL_MAPPING_WRBG = 201
  • BrickletLEDStripV2.CHANNEL_MAPPING_WRGB = 198
  • BrickletLEDStripV2.CHANNEL_MAPPING_WGBR = 216
  • BrickletLEDStripV2.CHANNEL_MAPPING_WGRB = 210
  • BrickletLEDStripV2.CHANNEL_MAPPING_WBGR = 228
  • BrickletLEDStripV2.CHANNEL_MAPPING_WBRG = 225
public int getChannelMapping()

Returns the currently used channel mapping as set by setChannelMapping().

The following constants are available for this function:

  • BrickletLEDStripV2.CHANNEL_MAPPING_RGB = 6
  • BrickletLEDStripV2.CHANNEL_MAPPING_RBG = 9
  • BrickletLEDStripV2.CHANNEL_MAPPING_BRG = 33
  • BrickletLEDStripV2.CHANNEL_MAPPING_BGR = 36
  • BrickletLEDStripV2.CHANNEL_MAPPING_GRB = 18
  • BrickletLEDStripV2.CHANNEL_MAPPING_GBR = 24
  • BrickletLEDStripV2.CHANNEL_MAPPING_RGBW = 27
  • BrickletLEDStripV2.CHANNEL_MAPPING_RGWB = 30
  • BrickletLEDStripV2.CHANNEL_MAPPING_RBGW = 39
  • BrickletLEDStripV2.CHANNEL_MAPPING_RBWG = 45
  • BrickletLEDStripV2.CHANNEL_MAPPING_RWGB = 54
  • BrickletLEDStripV2.CHANNEL_MAPPING_RWBG = 57
  • BrickletLEDStripV2.CHANNEL_MAPPING_GRWB = 78
  • BrickletLEDStripV2.CHANNEL_MAPPING_GRBW = 75
  • BrickletLEDStripV2.CHANNEL_MAPPING_GBWR = 108
  • BrickletLEDStripV2.CHANNEL_MAPPING_GBRW = 99
  • BrickletLEDStripV2.CHANNEL_MAPPING_GWBR = 120
  • BrickletLEDStripV2.CHANNEL_MAPPING_GWRB = 114
  • BrickletLEDStripV2.CHANNEL_MAPPING_BRGW = 135
  • BrickletLEDStripV2.CHANNEL_MAPPING_BRWG = 141
  • BrickletLEDStripV2.CHANNEL_MAPPING_BGRW = 147
  • BrickletLEDStripV2.CHANNEL_MAPPING_BGWR = 156
  • BrickletLEDStripV2.CHANNEL_MAPPING_BWRG = 177
  • BrickletLEDStripV2.CHANNEL_MAPPING_BWGR = 180
  • BrickletLEDStripV2.CHANNEL_MAPPING_WRBG = 201
  • BrickletLEDStripV2.CHANNEL_MAPPING_WRGB = 198
  • BrickletLEDStripV2.CHANNEL_MAPPING_WGBR = 216
  • BrickletLEDStripV2.CHANNEL_MAPPING_WGRB = 210
  • BrickletLEDStripV2.CHANNEL_MAPPING_WBGR = 228
  • BrickletLEDStripV2.CHANNEL_MAPPING_WBRG = 225

Advanced Functions

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 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.

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 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 function ID constants are available for this function:

  • BrickletLEDStripV2.FUNCTION_SET_LED_VALUES = 1
  • BrickletLEDStripV2.FUNCTION_SET_FRAME_DURATION = 3
  • BrickletLEDStripV2.FUNCTION_SET_CLOCK_FREQUENCY = 7
  • BrickletLEDStripV2.FUNCTION_SET_CHIP_TYPE = 9
  • BrickletLEDStripV2.FUNCTION_SET_CHANNEL_MAPPING = 11
  • BrickletLEDStripV2.FUNCTION_SET_FRAME_STARTED_CALLBACK_CONFIGURATION = 13
  • BrickletLEDStripV2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletLEDStripV2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletLEDStripV2.FUNCTION_RESET = 243
  • BrickletLEDStripV2.FUNCTION_WRITE_UID = 248
public void setResponseExpectedAll(boolean responseExpected)

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

public BrickletLEDStripV2.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:

  • BrickletLEDStripV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletLEDStripV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletLEDStripV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletLEDStripV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletLEDStripV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletLEDStripV2.BOOTLOADER_STATUS_OK = 0
  • BrickletLEDStripV2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletLEDStripV2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletLEDStripV2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletLEDStripV2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletLEDStripV2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletLEDStripV2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletLEDStripV2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletLEDStripV2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletLEDStripV2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletLEDStripV2.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:

  • BrickletLEDStripV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletLEDStripV2.STATUS_LED_CONFIG_ON = 1
  • BrickletLEDStripV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletLEDStripV2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletLEDStripV2.STATUS_LED_CONFIG_OFF = 0
  • BrickletLEDStripV2.STATUS_LED_CONFIG_ON = 1
  • BrickletLEDStripV2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletLEDStripV2.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 BrickletLEDStripV2.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.

Listener Configuration Functions

public void setFrameStartedCallbackConfiguration(boolean enable)

Enables/disables the FrameStartedListener listener.

By default the listener is enabled.

public boolean getFrameStartedCallbackConfiguration()

Returns the configuration as set by setFrameStartedCallbackConfiguration().

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 BrickletLEDStripV2.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.

public class BrickletLEDStripV2.FrameStartedListener()

This listener can be added with the addFrameStartedListener() function. An added listener can be removed with the removeFrameStartedListener() function.

public void frameStarted(int length)

This listener is triggered directly after a new frame render is started. The parameter is the number of LEDs in that frame.

You should send the data for the next frame directly after this listener was triggered.

For an explanation of the general approach see setLEDValues().

Constants

public static final int BrickletLEDStripV2.DEVICE_IDENTIFIER

This constant is used to identify a LED Strip Bricklet 2.0.

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

public static final String BrickletLEDStripV2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a LED Strip Bricklet 2.0.