Java - OLED 128x64 Bricklet 2.0

This is the description of the Java API bindings for the OLED 128x64 Bricklet 2.0. General information and technical specifications for the OLED 128x64 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).

Hello World

Download (ExampleHelloWorld.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
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletOLED128x64V2;

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

    // Change XYZ to the UID of your OLED 128x64 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
        BrickletOLED128x64V2 oled = new BrickletOLED128x64V2(UID, ipcon); // Create device object

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

        // Clear display
        oled.clearDisplay();

        // Write "Hello World" starting from upper left corner of the screen
        oled.writeLine(0, 0, "Hello World");

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

Pixel Matrix

Download (ExamplePixelMatrix.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
36
37
38
39
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletOLED128x64V2;

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

    // Change XYZ to the UID of your OLED 128x64 Bricklet
    private static final String UID = "XYZ";
    private static final short SCREEN_WIDTH = 128;
    private static final short SCREEN_HEIGHT = 64;

    // 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
        BrickletOLED128x64V2 oled = new BrickletOLED128x64V2(UID, ipcon); // Create device object

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

        // Clear display
        oled.clearDisplay();

        // Draw checkerboard pattern
        boolean[] pixels = new boolean[SCREEN_HEIGHT * SCREEN_WIDTH];

        for (short h = 0; h < SCREEN_HEIGHT; h++) {
            for (short w = 0; w < SCREEN_WIDTH; w++) {
                pixels[h*SCREEN_WIDTH + w] = (h / 8) % 2 == (w / 8) % 2;
            }
        }

        oled.writePixels(0, 0, SCREEN_WIDTH-1, SCREEN_HEIGHT-1, pixels);

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

Scribble

Download (ExampleScribble.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
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletOLED128x64V2;

public class ExampleScribble {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;
    private static final String UID = "XYZ"; // Change to your UID
    private static final short WIDTH = 128;
    private static final short HEIGHT = 64;

    static void drawImage(BrickletOLED128x64V2 oled, BufferedImage image) throws Exception {
        boolean[] pixels = new boolean[HEIGHT * WIDTH];
        short h, w;

        for (h = 0; h < HEIGHT; h++) {
            for (w = 0; w < WIDTH; w++) {
                pixels[h*WIDTH + w] = (image.getRGB(w, h) & 0x00FFFFFF) > 0;
            }
        }
        oled.writePixels(0, 0, WIDTH-1, HEIGHT-1, pixels);
    }

    // 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
        BrickletOLED128x64V2 oled = new BrickletOLED128x64V2(UID, ipcon); // Create device object

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

        // Clear display
        oled.clearDisplay();

        // Draw rotating line
        BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_ARGB);
        int originX = WIDTH / 2;
        int originY = HEIGHT / 2;
        int length = HEIGHT / 2 - 2;
        int angle = 0;

        System.out.println("Press ctrl+c to exit");

        while (true) {
            double radians = Math.toRadians(angle);
            int x = (int)(originX + length * Math.cos(radians));
            int y = (int)(originY + length * Math.sin(radians));
            Graphics g = image.createGraphics();

            g.setColor(Color.black);
            g.fillRect(0, 0, WIDTH, HEIGHT);
            g.setColor(Color.white);
            g.drawLine(originX, originY, x, y);
            g.dispose();

            drawImage(oled, image);
            Thread.sleep(25);

            angle++;
        }
    }
}

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 BrickletOLED128x64V2(String uid, IPConnection ipcon)

Creates an object with the unique device ID uid:

BrickletOLED128x64V2 oled128x64V2 = new BrickletOLED128x64V2("YOUR_DEVICE_UID", ipcon);

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

public void writePixels(int xStart, int yStart, int xEnd, int yEnd, boolean[] pixels)

Writes pixels to the specified window.

The x-axis goes from 0 to 127 and the y-axis from 0 to 63. The pixels are written into the window line by line top to bottom and each line is written from left to right.

If automatic draw is enabled (default) the pixels are directly written to the screen. Only pixels that have actually changed are updated on the screen, the rest stays the same.

If automatic draw is disabled the pixels are written to an internal buffer and the buffer is transferred to the display only after drawBufferedFrame() is called. This can be used to avoid flicker when drawing a complex frame in multiple steps.

Automatic draw can be configured with the setDisplayConfiguration() function.

public boolean[] readPixels(int xStart, int yStart, int xEnd, int yEnd)

Reads pixels from the specified window.

The x-axis goes from 0 to 127 and the y-axis from 0 to 63. The pixels are read from the window line by line top to bottom and each line is read from left to right.

If automatic draw is enabled (default) the pixels that are read are always the same that are shown on the display.

If automatic draw is disabled the pixels are read from the internal buffer (see drawBufferedFrame()).

Automatic draw can be configured with the setDisplayConfiguration() function.

public void clearDisplay()

Clears the complete content of the display.

public void writeLine(int line, int position, String text)

Writes text to a specific line (0 to 7) with a specific position (0 to 21). The text can have a maximum of 22 characters.

For example: (1, 10, "Hello") will write Hello in the middle of the second line of the display.

The display uses a special 5x7 pixel charset. You can view the characters of the charset in Brick Viewer.

public void drawBufferedFrame(boolean forceCompleteRedraw)

Draws the currently buffered frame. Normally each call of writePixels() and writeLine() draws directly onto the display. If you turn automatic draw off (setDisplayConfiguration()), the data is written in an internal buffer and only transferred to the display by calling this function. This can be used to avoid flicker when drawing a complex frame in multiple steps.

Set the force complete redraw to true to redraw the whole display instead of only the changed parts. Normally it should not be necessary to set this to true. It may only become necessary in case of stuck pixels because of errors.

Advanced Functions

public void setDisplayConfiguration(int contrast, boolean invert, boolean automaticDraw)

Sets the configuration of the display.

You can set a contrast value from 0 to 255 and you can invert the color (white/black) of the display.

If automatic draw is set to true, the display is automatically updated with every call of writePixels() or writeLine(). If it is set to false, the changes are written into an internal buffer and only shown on the display after a call of drawBufferedFrame().

The default values are contrast 143, inverting off and automatic draw on.

public BrickletOLED128x64V2.DisplayConfiguration getDisplayConfiguration()

Returns the configuration as set by setDisplayConfiguration().

The returned object has the public member variables int contrast, boolean invert and boolean automaticDraw.

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:

  • BrickletOLED128x64V2.FUNCTION_WRITE_PIXELS = 1
  • BrickletOLED128x64V2.FUNCTION_CLEAR_DISPLAY = 3
  • BrickletOLED128x64V2.FUNCTION_SET_DISPLAY_CONFIGURATION = 4
  • BrickletOLED128x64V2.FUNCTION_WRITE_LINE = 6
  • BrickletOLED128x64V2.FUNCTION_DRAW_BUFFERED_FRAME = 7
  • BrickletOLED128x64V2.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletOLED128x64V2.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletOLED128x64V2.FUNCTION_RESET = 243
  • BrickletOLED128x64V2.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 BrickletOLED128x64V2.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:

  • BrickletOLED128x64V2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletOLED128x64V2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletOLED128x64V2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletOLED128x64V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletOLED128x64V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletOLED128x64V2.BOOTLOADER_STATUS_OK = 0
  • BrickletOLED128x64V2.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletOLED128x64V2.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletOLED128x64V2.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletOLED128x64V2.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletOLED128x64V2.BOOTLOADER_STATUS_CRC_MISMATCH = 5
public int getBootloaderMode()

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

  • BrickletOLED128x64V2.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletOLED128x64V2.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletOLED128x64V2.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletOLED128x64V2.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletOLED128x64V2.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:

  • BrickletOLED128x64V2.STATUS_LED_CONFIG_OFF = 0
  • BrickletOLED128x64V2.STATUS_LED_CONFIG_ON = 1
  • BrickletOLED128x64V2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOLED128x64V2.STATUS_LED_CONFIG_SHOW_STATUS = 3
public int getStatusLEDConfig()

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

  • BrickletOLED128x64V2.STATUS_LED_CONFIG_OFF = 0
  • BrickletOLED128x64V2.STATUS_LED_CONFIG_ON = 1
  • BrickletOLED128x64V2.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOLED128x64V2.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 BrickletOLED128x64V2.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.

Constants

public static final int BrickletOLED128x64V2.DEVICE_IDENTIFIER

This constant is used to identify a OLED 128x64 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 BrickletOLED128x64V2.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a OLED 128x64 Bricklet 2.0.