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Software / API Bindings / Java / API Reference and Examples / Bricklets / One Wire Bricklet

Java - One Wire Bricklet

This is the description of the Java API bindings for the One Wire Bricklet. General information and technical specifications for the One Wire 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).

Read DS 18B 20Temperature

Download (ExampleReadDS18B20Temperature.java)

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import com.tinkerforge.IPConnection;
import com.tinkerforge.BrickletOneWire;

public class ExampleReadDS18B20Temperature {
    private static final String HOST = "localhost";
    private static final int PORT = 4223;

    // Change XYZ to the UID of your One Wire 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
        BrickletOneWire ow = new BrickletOneWire(UID, ipcon); // Create device object

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

        ow.writeCommand(0, 78); // WRITE SCRATCHPAD
        ow.write(0); // ALARM H (unused)
        ow.write(0); // ALARM L (unused)
        ow.write(127); // CONFIGURATION: 12-bit mode

        // Read temperature 10 times
        for(int i = 0; i < 10; i++) {
            ow.writeCommand(0, 68); // CONVERT T (start temperature conversion)
            Thread.sleep(1000); // Wait for conversion to finish
            ow.writeCommand(0, 190); // READ SCRATCHPAD

            int tLow = ow.read().data;
            int tHigh = ow.read().data;

            float temperature = tLow | (tHigh << 8);

            // Negative 12-bit values are sign-extended to 16-bit two's complement
            if (temperature > 1 << 12) {
                temperature -= 1 << 16;
            }

            // 12-bit mode measures in units of 1/16°C
            System.out.println("Temperature: " + temperature/16.0 + " °C");
        }

        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 BrickletOneWire(String uid, IPConnection ipcon)
Parameters:
  • uid – Type: String
  • ipcon – Type: IPConnection
Returns:
  • oneWire – Type: BrickletOneWire

Creates an object with the unique device ID uid:

BrickletOneWire oneWire = new BrickletOneWire("YOUR_DEVICE_UID", ipcon);

This object can then be used after the IP Connection is connected.

BrickletOneWire.SearchBus BrickletOneWire.searchBus()
Return Object:
  • identifier – Type: long[], Length: variable, Range: [0 to 264 - 1]
  • status – Type: int, Range: See constants

Returns a list of up to 64 identifiers of the connected 1-Wire devices. Each identifier is 64-bit and consists of 8-bit family code, 48-bit ID and 8-bit CRC.

To get these identifiers the Bricklet runs the SEARCH ROM algorithm, as defined by Maxim.

The following constants are available for this function:

For status:

  • BrickletOneWire.STATUS_OK = 0
  • BrickletOneWire.STATUS_BUSY = 1
  • BrickletOneWire.STATUS_NO_PRESENCE = 2
  • BrickletOneWire.STATUS_TIMEOUT = 3
  • BrickletOneWire.STATUS_ERROR = 4
int BrickletOneWire.resetBus()
Returns:
  • status – Type: int, Range: See constants

Resets the bus with the 1-Wire reset operation.

The following constants are available for this function:

For status:

  • BrickletOneWire.STATUS_OK = 0
  • BrickletOneWire.STATUS_BUSY = 1
  • BrickletOneWire.STATUS_NO_PRESENCE = 2
  • BrickletOneWire.STATUS_TIMEOUT = 3
  • BrickletOneWire.STATUS_ERROR = 4
int BrickletOneWire.write(int data)
Parameters:
  • data – Type: int, Range: [0 to 255]
Returns:
  • status – Type: int, Range: See constants

Writes a byte of data to the 1-Wire bus.

The following constants are available for this function:

For status:

  • BrickletOneWire.STATUS_OK = 0
  • BrickletOneWire.STATUS_BUSY = 1
  • BrickletOneWire.STATUS_NO_PRESENCE = 2
  • BrickletOneWire.STATUS_TIMEOUT = 3
  • BrickletOneWire.STATUS_ERROR = 4
BrickletOneWire.Read BrickletOneWire.read()
Return Object:
  • data – Type: int, Range: [0 to 255]
  • status – Type: int, Range: See constants

Reads a byte of data from the 1-Wire bus.

The following constants are available for this function:

For status:

  • BrickletOneWire.STATUS_OK = 0
  • BrickletOneWire.STATUS_BUSY = 1
  • BrickletOneWire.STATUS_NO_PRESENCE = 2
  • BrickletOneWire.STATUS_TIMEOUT = 3
  • BrickletOneWire.STATUS_ERROR = 4
int BrickletOneWire.writeCommand(long identifier, int command)
Parameters:
  • identifier – Type: long, Range: [0 to 264 - 1]
  • command – Type: int, Range: [0 to 255]
Returns:
  • status – Type: int, Range: See constants

Writes a command to the 1-Wire device with the given identifier. You can obtain the identifier by calling searchBus(). The MATCH ROM operation is used to write the command.

If you only have one device connected or want to broadcast to all devices you can set the identifier to 0. In this case the SKIP ROM operation is used to write the command.

The following constants are available for this function:

For status:

  • BrickletOneWire.STATUS_OK = 0
  • BrickletOneWire.STATUS_BUSY = 1
  • BrickletOneWire.STATUS_NO_PRESENCE = 2
  • BrickletOneWire.STATUS_TIMEOUT = 3
  • BrickletOneWire.STATUS_ERROR = 4

Advanced Functions

void BrickletOneWire.setCommunicationLEDConfig(int config)
Parameters:
  • config – Type: int, Range: See constants, Default: 3

Sets the communication LED configuration. By default the LED shows 1-wire communication traffic by flickering.

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

If the Bricklet is in bootloader mode, the LED is off.

The following constants are available for this function:

For config:

  • BrickletOneWire.COMMUNICATION_LED_CONFIG_OFF = 0
  • BrickletOneWire.COMMUNICATION_LED_CONFIG_ON = 1
  • BrickletOneWire.COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOneWire.COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
int BrickletOneWire.getCommunicationLEDConfig()
Returns:
  • config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by setCommunicationLEDConfig()

The following constants are available for this function:

For config:

  • BrickletOneWire.COMMUNICATION_LED_CONFIG_OFF = 0
  • BrickletOneWire.COMMUNICATION_LED_CONFIG_ON = 1
  • BrickletOneWire.COMMUNICATION_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOneWire.COMMUNICATION_LED_CONFIG_SHOW_COMMUNICATION = 3
BrickletOneWire.SPITFPErrorCount BrickletOneWire.getSPITFPErrorCount()
Return Object:
  • errorCountAckChecksum – Type: long, Range: [0 to 232 - 1]
  • errorCountMessageChecksum – Type: long, Range: [0 to 232 - 1]
  • errorCountFrame – Type: long, Range: [0 to 232 - 1]
  • errorCountOverflow – Type: long, Range: [0 to 232 - 1]

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.

void BrickletOneWire.setStatusLEDConfig(int config)
Parameters:
  • config – Type: int, Range: See constants, Default: 3

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:

For config:

  • BrickletOneWire.STATUS_LED_CONFIG_OFF = 0
  • BrickletOneWire.STATUS_LED_CONFIG_ON = 1
  • BrickletOneWire.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOneWire.STATUS_LED_CONFIG_SHOW_STATUS = 3
int BrickletOneWire.getStatusLEDConfig()
Returns:
  • config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by setStatusLEDConfig()

The following constants are available for this function:

For config:

  • BrickletOneWire.STATUS_LED_CONFIG_OFF = 0
  • BrickletOneWire.STATUS_LED_CONFIG_ON = 1
  • BrickletOneWire.STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletOneWire.STATUS_LED_CONFIG_SHOW_STATUS = 3
int BrickletOneWire.getChipTemperature()
Returns:
  • temperature – Type: int, Unit: 1 °C, Range: [-215 to 215 - 1]

Returns the temperature 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.

void BrickletOneWire.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!

BrickletOneWire.Identity BrickletOneWire.getIdentity()
Return Object:
  • uid – Type: String, Length: up to 8
  • connectedUid – Type: String, Length: up to 8
  • position – Type: char, Range: ['a' to 'h', 'z']
  • hardwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • firmwareVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]
  • deviceIdentifier – Type: int, Range: [0 to 216 - 1]

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', 'd', 'e', 'f', 'g' or 'h' (Bricklet Port). A Bricklet connected to an Isolator Bricklet is always at position 'z'.

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

Virtual Functions

Virtual functions don't communicate with the device itself, but operate only on the API bindings device object. They can be called without the corresponding IP Connection object being connected.

short[] BrickletOneWire.getAPIVersion()
Return Object:
  • apiVersion – Type: short[], Length: 3
    • 0: major – Type: short, Range: [0 to 255]
    • 1: minor – Type: short, Range: [0 to 255]
    • 2: revision – Type: short, Range: [0 to 255]

Returns the version of the API definition 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 BrickletOneWire.getResponseExpected(byte functionId)
Parameters:
  • functionId – Type: byte, Range: See constants
Returns:
  • responseExpected – Type: boolean

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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletOneWire.FUNCTION_SET_COMMUNICATION_LED_CONFIG = 6
  • BrickletOneWire.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletOneWire.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletOneWire.FUNCTION_RESET = 243
  • BrickletOneWire.FUNCTION_WRITE_UID = 248
void BrickletOneWire.setResponseExpected(byte functionId, boolean responseExpected)
Parameters:
  • functionId – Type: byte, Range: See constants
  • responseExpected – Type: boolean

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 sent and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

For functionId:

  • BrickletOneWire.FUNCTION_SET_COMMUNICATION_LED_CONFIG = 6
  • BrickletOneWire.FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletOneWire.FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletOneWire.FUNCTION_RESET = 243
  • BrickletOneWire.FUNCTION_WRITE_UID = 248
void BrickletOneWire.setResponseExpectedAll(boolean responseExpected)
Parameters:
  • responseExpected – Type: boolean

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

Internal Functions

Internal functions are used for maintenance tasks such as flashing a new firmware of changing the UID of a Bricklet. These task should be performed using Brick Viewer instead of using the internal functions directly.

int BrickletOneWire.setBootloaderMode(int mode)
Parameters:
  • mode – Type: int, Range: See constants
Returns:
  • status – Type: int, Range: See constants

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:

For mode:

  • BrickletOneWire.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletOneWire.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletOneWire.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletOneWire.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletOneWire.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4

For status:

  • BrickletOneWire.BOOTLOADER_STATUS_OK = 0
  • BrickletOneWire.BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletOneWire.BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletOneWire.BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletOneWire.BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletOneWire.BOOTLOADER_STATUS_CRC_MISMATCH = 5
int BrickletOneWire.getBootloaderMode()
Returns:
  • mode – Type: int, Range: See constants

Returns the current bootloader mode, see setBootloaderMode().

The following constants are available for this function:

For mode:

  • BrickletOneWire.BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletOneWire.BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletOneWire.BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletOneWire.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletOneWire.BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
void BrickletOneWire.setWriteFirmwarePointer(long pointer)
Parameters:
  • pointer – Type: long, Unit: 1 B, Range: [0 to 232 - 1]

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.

int BrickletOneWire.writeFirmware(int[] data)
Parameters:
  • data – Type: int[], Length: 64, Range: [0 to 255]
Returns:
  • status – Type: int, Range: [0 to 255]

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.

void BrickletOneWire.writeUID(long uid)
Parameters:
  • uid – Type: long, Range: [0 to 232 - 1]

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.

long BrickletOneWire.readUID()
Returns:
  • uid – Type: long, Range: [0 to 232 - 1]

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

Constants

int BrickletOneWire.DEVICE_IDENTIFIER

This constant is used to identify a One Wire 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.

String BrickletOneWire.DEVICE_DISPLAY_NAME

This constant represents the human readable name of a One Wire Bricklet.