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

Perl - One Wire Bricklet¶

This is the description of the Perl 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 Perl API bindings is part of their general description.

Examples¶

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

Read Ds18b20 Temperature¶

Download (example_read_ds18b20_temperature.pl)

#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletOneWire;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your One Wire Bricklet

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $ow = Tinkerforge::BrickletOneWire->new(&UID, $ipcon); # Create device object

$ipcon->connect(&HOST, &PORT); # Connect to brickd
# Don't use device before ipcon is connected

$ow->write_command(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 (my $i = 0; $i < 10; $i++)
{
    $ow->write_command(0, 68); # CONVERT T (start temperature conversion)
    sleep(1); # Wait for conversion to finish
    $ow->write_command(0, 190); # READ SCRATCHPAD

    my ($t_low, $status1) = $ow->read();
    my ($t_high, $status2) = $ow->read();
    my $temperature = $t_low | ($t_high << 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
    print "Temperature: " . $temperature/16.0 . " °C\n";
}

print "Press key to exit\n";
<STDIN>;
$ipcon->disconnect();

API¶

Generally, every subroutine of the Perl bindings can report an error as Tinkerforge::Error object via croak(). The object has a get_code() and a get_message() subroutine. There are different error code:

Error->ALREADY_CONNECTED = 11
Error->NOT_CONNECTED = 12
Error->CONNECT_FAILED = 13
Error->INVALID_FUNCTION_ID = 21
Error->TIMEOUT = 31
Error->INVALID_PARAMETER = 41
Error->FUNCTION_NOT_SUPPORTED = 42
Error->UNKNOWN_ERROR = 43
Error->STREAM_OUT_OF_SYNC = 51
Error->INVALID_UID = 61
Error->NON_ASCII_CHAR_IN_SECRET = 71
Error->WRONG_DEVICE_TYPE = 81
Error->DEVICE_REPLACED = 82
Error->WRONG_RESPONSE_LENGTH = 83

All functions listed below are thread-safe.

Basic Functions¶

BrickletOneWire->new($uid, $ipcon)¶

Parameters:	$uid – Type: string $ipcon – Type: IPConnection
Returns:	$one_wire – Type: BrickletOneWire

Creates an object with the unique device ID $uid:

$one_wire = BrickletOneWire->new("YOUR_DEVICE_UID", $ipcon);

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

BrickletOneWire->search_bus()¶

Return Array:	0: \@identifier – Type: [int, ...], Length: variable, Range: [0 to 2⁶⁴ - 1] 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

BrickletOneWire->reset_bus()¶

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

BrickletOneWire->write($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()¶

Return Array:	0: $data – Type: int, Range: [0 to 255] 1: $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

BrickletOneWire->write_command($identifier, $command)¶

Parameters:	$identifier – Type: int, 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 search_bus(). 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¶

BrickletOneWire->set_communication_led_config($config)¶

Parameters:	$config – Type: int, Range: See constants, Default: 3
Returns:	undef

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

BrickletOneWire->get_communication_led_config()¶

Returns:	$config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by set_communication_led_config()

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->get_spitfp_error_count()¶

Return Array:	0: $error_count_ack_checksum – Type: int, Range: [0 to 2³² - 1] 1: $error_count_message_checksum – Type: int, Range: [0 to 2³² - 1] 2: $error_count_frame – Type: int, Range: [0 to 2³² - 1] 3: $error_count_overflow – Type: int, 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.

BrickletOneWire->set_status_led_config($config)¶

Parameters:	$config – Type: int, Range: See constants, Default: 3
Returns:	undef

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

BrickletOneWire->get_status_led_config()¶

Returns:	$config – Type: int, Range: See constants, Default: 3

Returns the configuration as set by set_status_led_config()

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

BrickletOneWire->get_chip_temperature()¶

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.

BrickletOneWire->reset()¶

Returns:	undef

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->get_identity()¶

Return Array:

Return Array:	0: $uid – Type: string, Length: up to 8 1: $connected_uid – Type: string, Length: up to 8 2: $position – Type: char, Range: ['a' to 'h', 'z'] 3: \@hardware_version – Type: [int, ...], Length: 3 0: $major – Type: int, Range: [0 to 255] 1: $minor – Type: int, Range: [0 to 255] 2: $revision – Type: int, Range: [0 to 255] 4: \@firmware_version – Type: [int, ...], Length: 3 0: $major – Type: int, Range: [0 to 255] 1: $minor – Type: int, Range: [0 to 255] 2: $revision – Type: int, Range: [0 to 255] 5: $device_identifier – Type: int, Range: [0 to 2¹⁶ - 1]

0: $uid – Type: string, Length: up to 8
1: $connected_uid – Type: string, Length: up to 8
2: $position – Type: char, Range: ['a' to 'h', 'z']
3: \@hardware_version – Type: [int, ...], Length: 3

0: $major – Type: int, Range: [0 to 255]
1: $minor – Type: int, Range: [0 to 255]
2: $revision – Type: int, Range: [0 to 255]

4: \@firmware_version – Type: [int, ...], Length: 3

0: $major – Type: int, Range: [0 to 255]
1: $minor – Type: int, Range: [0 to 255]
2: $revision – Type: int, Range: [0 to 255]

5: $device_identifier – 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.

BrickletOneWire->get_api_version()¶

Return Array:	0: \@api_version – Type: [int, ...], Length: 3 0: $major – Type: int, Range: [0 to 255] 1: $minor – Type: int, Range: [0 to 255] 2: $revision – Type: int, 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.

BrickletOneWire->get_response_expected($function_id)¶

Parameters:	$function_id – Type: int, Range: See constants
Returns:	$response_expected – Type: bool

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 set_response_expected(). 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 $function_id:

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

BrickletOneWire->set_response_expected($function_id, $response_expected)¶

Parameters:	$function_id – Type: int, Range: See constants $response_expected – Type: bool
Returns:	undef

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.

The following constants are available for this function:

For $function_id:

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

BrickletOneWire->set_response_expected_all($response_expected)¶

Parameters:	$response_expected – Type: bool
Returns:	undef

Changes the response expected flag for all setter and callback 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.

BrickletOneWire->set_bootloader_mode($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

BrickletOneWire->get_bootloader_mode()¶

Returns:	$mode – Type: int, Range: See constants

Returns the current bootloader mode, see set_bootloader_mode().

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

BrickletOneWire->set_write_firmware_pointer($pointer)¶

Parameters:	$pointer – Type: int, Unit: 1 B, Range: [0 to 2³² - 1]
Returns:	undef

Sets the firmware pointer for write_firmware(). 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.

BrickletOneWire->write_firmware(\@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 set_write_firmware_pointer() 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.

BrickletOneWire->write_uid($uid)¶

Parameters:	$uid – Type: int, Range: [0 to 2³² - 1]
Returns:	undef

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.

BrickletOneWire->read_uid()¶

Returns:	$uid – Type: int, Range: [0 to 2³² - 1]

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

Constants¶

BrickletOneWire->DEVICE_IDENTIFIER¶

This constant is used to identify a One Wire Bricklet.

The get_identity() function and the IPConnection->CALLBACK_ENUMERATE callback of the IP Connection have a device_identifier parameter to specify the Brick's or Bricklet's type.

BrickletOneWire->DEVICE_DISPLAY_NAME¶: This constant represents the human readable name of a One Wire Bricklet.