Perl - Hall Effect Bricklet 2.0

This is the description of the Perl API bindings for the Hall Effect Bricklet 2.0. General information and technical specifications for the Hall Effect Bricklet 2.0 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).

Counter

Download (example_counter.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletHallEffectV2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Hall Effect Bricklet 2.0

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $he = Tinkerforge::BrickletHallEffectV2->new(&UID, $ipcon); # Create device object

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

# Get current count without counter reset
my $count = $he->get_counter(0);
print "Count: $count\n";

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

Magnetic Flux Density

Download (example_magnetic_flux_density.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletHallEffectV2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Hall Effect Bricklet 2.0

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $he = Tinkerforge::BrickletHallEffectV2->new(&UID, $ipcon); # Create device object

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

# Get current Magnetic Flux Density
my $magnetic_flux_density = $he->get_magnetic_flux_density();
print "Magnetic Flux Density: $magnetic_flux_density µT\n";

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

Counter Callback

Download (example_counter_callback.pl)

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#!/usr/bin/perl

use strict;
use Tinkerforge::IPConnection;
use Tinkerforge::BrickletHallEffectV2;

use constant HOST => 'localhost';
use constant PORT => 4223;
use constant UID => 'XYZ'; # Change XYZ to the UID of your Hall Effect Bricklet 2.0

# Callback subroutine for counter callback
sub cb_counter
{
    my ($counter) = @_;

    print "Counter: $counter\n";
}

my $ipcon = Tinkerforge::IPConnection->new(); # Create IP connection
my $he = Tinkerforge::BrickletHallEffectV2->new(&UID, $ipcon); # Create device object

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

# Configure counter with ±3000µT threshold and 10ms debounce
$he->set_counter_config(3000, -3000, 10000);

# Register counter callback to subroutine cb_counter
$he->register_callback($he->CALLBACK_COUNTER, 'cb_counter');

# Set period for counter callback to 0.1s (100ms)
$he->set_counter_callback_configuration(100, 1);

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

All methods listed below are thread-safe.

Basic Functions

BrickletHallEffectV2->new($uid, $ipcon)
Parameters:
  • $uid -- string
  • $ipcon -- IPConnection
Return type:

BrickletHallEffectV2

Creates an object with the unique device ID $uid:

$hall_effect_v2 = BrickletHallEffectV2->new("YOUR_DEVICE_UID", $ipcon);

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

BrickletHallEffectV2->get_magnetic_flux_density()
Return type:int

Returns the magnetic flux density (magnetic induction) in µT (micro Tesla).

If you want to get the value periodically, it is recommended to use the CALLBACK_MAGNETIC_FLUX_DENSITY callback. You can set the callback configuration with set_magnetic_flux_density_callback_configuration().

BrickletHallEffectV2->get_counter($reset_counter)
Parameters:$reset_counter -- bool
Return type:int

Returns the current value of the counter.

You can configure the low/high thresholds in µT and the debounce time in us with set_counter_config().

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

If you want to get the count periodically, it is recommended to use the CALLBACK_COUNTER callback. You can set the callback configuration with set_counter_callback_configuration().

BrickletHallEffectV2->set_counter_config($high_threshold, $low_threshold, $debounce)
Parameters:
  • $high_threshold -- int
  • $low_threshold -- int
  • $debounce -- int
Return type:

undef

Sets a high and a low threshold in µT as well as a debounce time in µs.

If the measured magnetic flux density goes above the high threshold or below the low threshold, the count of the counter is increased by 1.

The debounce time is the minimum time between two count increments.

The default values are

  • High Threshold: 2000µT
  • Low Threshold: -2000µT
  • Debounce: 100000µs (100ms)
BrickletHallEffectV2->get_counter_config()
Return type:[int, int, int]

Returns the counter config as set by set_counter_config().

The returned array contains the elements high_threshold, low_threshold and debounce.

Advanced Functions

BrickletHallEffectV2->get_api_version()
Return type:[int, int, int]

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.

BrickletHallEffectV2->get_response_expected($function_id)
Parameters:$function_id -- int
Return 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 send and errors are silently ignored, because they cannot be detected.

The following constants are available for this function:

  • BrickletHallEffectV2->FUNCTION_SET_MAGNETIC_FLUX_DENSITY_CALLBACK_CONFIGURATION = 2
  • BrickletHallEffectV2->FUNCTION_SET_COUNTER_CONFIG = 6
  • BrickletHallEffectV2->FUNCTION_SET_COUNTER_CALLBACK_CONFIGURATION = 8
  • BrickletHallEffectV2->FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletHallEffectV2->FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletHallEffectV2->FUNCTION_RESET = 243
  • BrickletHallEffectV2->FUNCTION_WRITE_UID = 248
BrickletHallEffectV2->set_response_expected($function_id, $response_expected)
Parameters:
  • $function_id -- int
  • $response_expected -- bool
Return type:

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.

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:

  • BrickletHallEffectV2->FUNCTION_SET_MAGNETIC_FLUX_DENSITY_CALLBACK_CONFIGURATION = 2
  • BrickletHallEffectV2->FUNCTION_SET_COUNTER_CONFIG = 6
  • BrickletHallEffectV2->FUNCTION_SET_COUNTER_CALLBACK_CONFIGURATION = 8
  • BrickletHallEffectV2->FUNCTION_SET_WRITE_FIRMWARE_POINTER = 237
  • BrickletHallEffectV2->FUNCTION_SET_STATUS_LED_CONFIG = 239
  • BrickletHallEffectV2->FUNCTION_RESET = 243
  • BrickletHallEffectV2->FUNCTION_WRITE_UID = 248
BrickletHallEffectV2->set_response_expected_all($response_expected)
Parameters:$response_expected -- bool
Return type:undef

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

BrickletHallEffectV2->get_spitfp_error_count()
Return type:[int, int, int, int]

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 array contains the elements error_count_ack_checksum, error_count_message_checksum, error_count_frame and error_count_overflow.

BrickletHallEffectV2->set_bootloader_mode($mode)
Parameters:$mode -- int
Return type:int

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:

  • BrickletHallEffectV2->BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletHallEffectV2->BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletHallEffectV2->BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletHallEffectV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletHallEffectV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
  • BrickletHallEffectV2->BOOTLOADER_STATUS_OK = 0
  • BrickletHallEffectV2->BOOTLOADER_STATUS_INVALID_MODE = 1
  • BrickletHallEffectV2->BOOTLOADER_STATUS_NO_CHANGE = 2
  • BrickletHallEffectV2->BOOTLOADER_STATUS_ENTRY_FUNCTION_NOT_PRESENT = 3
  • BrickletHallEffectV2->BOOTLOADER_STATUS_DEVICE_IDENTIFIER_INCORRECT = 4
  • BrickletHallEffectV2->BOOTLOADER_STATUS_CRC_MISMATCH = 5
BrickletHallEffectV2->get_bootloader_mode()
Return type:int

Returns the current bootloader mode, see set_bootloader_mode().

The following constants are available for this function:

  • BrickletHallEffectV2->BOOTLOADER_MODE_BOOTLOADER = 0
  • BrickletHallEffectV2->BOOTLOADER_MODE_FIRMWARE = 1
  • BrickletHallEffectV2->BOOTLOADER_MODE_BOOTLOADER_WAIT_FOR_REBOOT = 2
  • BrickletHallEffectV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_REBOOT = 3
  • BrickletHallEffectV2->BOOTLOADER_MODE_FIRMWARE_WAIT_FOR_ERASE_AND_REBOOT = 4
BrickletHallEffectV2->set_write_firmware_pointer($pointer)
Parameters:$pointer -- int
Return type: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.

BrickletHallEffectV2->write_firmware(@data)
Parameters:@data -- [int, int, ..61x.., int]
Return type:int

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.

BrickletHallEffectV2->set_status_led_config($config)
Parameters:$config -- int
Return type: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:

  • BrickletHallEffectV2->STATUS_LED_CONFIG_OFF = 0
  • BrickletHallEffectV2->STATUS_LED_CONFIG_ON = 1
  • BrickletHallEffectV2->STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletHallEffectV2->STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletHallEffectV2->get_status_led_config()
Return type:int

Returns the configuration as set by set_status_led_config()

The following constants are available for this function:

  • BrickletHallEffectV2->STATUS_LED_CONFIG_OFF = 0
  • BrickletHallEffectV2->STATUS_LED_CONFIG_ON = 1
  • BrickletHallEffectV2->STATUS_LED_CONFIG_SHOW_HEARTBEAT = 2
  • BrickletHallEffectV2->STATUS_LED_CONFIG_SHOW_STATUS = 3
BrickletHallEffectV2->get_chip_temperature()
Return type:int

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.

BrickletHallEffectV2->reset()
Return type: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!

BrickletHallEffectV2->write_uid($uid)
Parameters:$uid -- int
Return type: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.

BrickletHallEffectV2->read_uid()
Return type:int

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

BrickletHallEffectV2->get_identity()
Return type:[string, string, char, [int, int, int], [int, int, int], int]

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 array contains the elements uid, connected_uid, position, hardware_version, firmware_version and device_identifier.

Callback Configuration Functions

BrickletHallEffectV2->register_callback($id, $callback)
Parameters:
  • $id -- int
  • $callback -- string
Return type:

undef

Registers the given $function name with the given $callback_id.

The available callback IDs with corresponding function signatures are listed below.

BrickletHallEffectV2->set_magnetic_flux_density_callback_configuration($period, $value_has_to_change, $option, $min, $max)
Parameters:
  • $period -- int
  • $value_has_to_change -- bool
  • $option -- char
  • $min -- int
  • $max -- int
Return type:

undef

The period in ms is the period with which the CALLBACK_MAGNETIC_FLUX_DENSITY callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after the value has changed. If the value didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

It is furthermore possible to constrain the callback with thresholds.

The option-parameter together with min/max sets a threshold for the CALLBACK_MAGNETIC_FLUX_DENSITY callback.

The following options are possible:

Option Description
'x' Threshold is turned off
'o' Threshold is triggered when the value is outside the min and max values
'i' Threshold is triggered when the value is inside or equal to the min and max values
'<' Threshold is triggered when the value is smaller than the min value (max is ignored)
'>' Threshold is triggered when the value is greater than the min value (max is ignored)

If the option is set to 'x' (threshold turned off) the callback is triggered with the fixed period.

The default value is (0, false, 'x', 0, 0).

The following constants are available for this function:

  • BrickletHallEffectV2->THRESHOLD_OPTION_OFF = 'x'
  • BrickletHallEffectV2->THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletHallEffectV2->THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletHallEffectV2->THRESHOLD_OPTION_SMALLER = '<'
  • BrickletHallEffectV2->THRESHOLD_OPTION_GREATER = '>'
BrickletHallEffectV2->get_magnetic_flux_density_callback_configuration()
Return type:[int, bool, char, int, int]

Returns the callback configuration as set by set_magnetic_flux_density_callback_configuration().

The following constants are available for this function:

  • BrickletHallEffectV2->THRESHOLD_OPTION_OFF = 'x'
  • BrickletHallEffectV2->THRESHOLD_OPTION_OUTSIDE = 'o'
  • BrickletHallEffectV2->THRESHOLD_OPTION_INSIDE = 'i'
  • BrickletHallEffectV2->THRESHOLD_OPTION_SMALLER = '<'
  • BrickletHallEffectV2->THRESHOLD_OPTION_GREATER = '>'

The returned array contains the elements period, value_has_to_change, option, min and max.

BrickletHallEffectV2->set_counter_callback_configuration($period, $value_has_to_change)
Parameters:
  • $period -- int
  • $value_has_to_change -- bool
Return type:

undef

The period in ms is the period with which the CALLBACK_COUNTER callback is triggered periodically. A value of 0 turns the callback off.

If the value has to change-parameter is set to true, the callback is only triggered after at least one of the values has changed. If the values didn't change within the period, the callback is triggered immediately on change.

If it is set to false, the callback is continuously triggered with the period, independent of the value.

The default value is (0, false).

BrickletHallEffectV2->get_counter_callback_configuration()
Return type:[int, bool]

Returns the callback configuration as set by set_counter_callback_configuration().

The returned array contains the elements period and value_has_to_change.

Callbacks

Callbacks can be registered to receive time critical or recurring data from the device. The registration is done with the register_callback() function of the device object. The first parameter is the callback ID and the second parameter the callback function name:

sub my_callback
{
    print "@_[0]";
}

$hall_effect_v2->register_callback(BrickletHallEffectV2->CALLBACK_EXAMPLE, 'my_callback')

The callback function will be called from an internal thread of the IP Connection. In contrast to many other programming languages, variables are not automatically shared between threads in Perl. If you want to share a global variable between a callback function and the rest for your program it has to be marked as :shared. See the documentation of the threads::shared Perl module for more details.

The available constants with inherent number and type of parameters are described below.

Note

Using callbacks 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.

BrickletHallEffectV2->CALLBACK_MAGNETIC_FLUX_DENSITY
Parameters:$magnetic_flux_density -- int

This callback is triggered periodically according to the configuration set by set_magnetic_flux_density_callback_configuration().

The parameter is the same as get_magnetic_flux_density().

BrickletHallEffectV2->CALLBACK_COUNTER
Parameters:$count -- int

This callback is triggered periodically according to the configuration set by set_counter_callback_configuration().

The count is the same as you would get with get_counter().

Constants

BrickletHallEffectV2->DEVICE_IDENTIFIER

This constant is used to identify a Hall Effect Bricklet 2.0.

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.

BrickletHallEffectV2->DEVICE_DISPLAY_NAME

This constant represents the human readable name of a Hall Effect Bricklet 2.0.