..
 #############################################################
 # This file was automatically generated on 2015-05-08.      #
 #                                                           #
 # If you have a bugfix for this file and want to commit it, #
 # please fix the bug in the generator. You can find a link  #
 # to the generators git repository on tinkerforge.com       #
 #############################################################


:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-delphi">Software</a> / Delphi/Lazarus - Barometer Bricklet

.. |device_identifier_constant| replace:: There is also a :ref:`constant <barometer_bricklet_delphi_constants>` for the device identifier of this Bricklet.

.. _barometer_bricklet_delphi:

Delphi/Lazarus - Barometer Bricklet
===================================

This is the description of the :ref:`Delphi/Lazarus API bindings <api_bindings_delphi>` for the :ref:`Barometer Bricklet <barometer_bricklet>`. General information and technical
specifications for the Barometer Bricklet are summarized in its :ref:`hardware description
<barometer_bricklet_description>`.

An :ref:`installation guide <api_bindings_delphi_install>` for the Delphi/Lazarus API
bindings is part of their general description.

.. _barometer_bricklet_delphi_examples:


Examples
--------

The example code below is `Public Domain (CC0 1.0)
<http://creativecommons.org/publicdomain/zero/1.0/>`__.

Simple
^^^^^^

`Download (ExampleSimple.pas) <https://github.com/Tinkerforge/barometer-bricklet/raw/master/software/examples/delphi/ExampleSimple.pas>`__

.. literalinclude:: Barometer_Bricklet_Delphi_ExampleSimple.pas
 :language: delphi
 :linenos:
 :tab-width: 4

Threshold
^^^^^^^^^

`Download (ExampleThreshold.pas) <https://github.com/Tinkerforge/barometer-bricklet/raw/master/software/examples/delphi/ExampleThreshold.pas>`__

.. literalinclude:: Barometer_Bricklet_Delphi_ExampleThreshold.pas
 :language: delphi
 :linenos:
 :tab-width: 4

Callback
^^^^^^^^

`Download (ExampleCallback.pas) <https://github.com/Tinkerforge/barometer-bricklet/raw/master/software/examples/delphi/ExampleCallback.pas>`__

.. literalinclude:: Barometer_Bricklet_Delphi_ExampleCallback.pas
 :language: delphi
 :linenos:
 :tab-width: 4

.. _barometer_bricklet_delphi_api:

API
---

Since Delphi does not support multiple return values directly, we use the
``out`` keyword to return multiple values from a function.

All functions and procedures listed below are thread-safe.




Basic Functions
^^^^^^^^^^^^^^^


.. delphi:function:: constructor TBrickletBarometer.Create(const uid: string; ipcon: TIPConnection)

 Creates an object with the unique device ID ``uid``:

 .. code-block:: delphi

    barometer := TBrickletBarometer.Create('YOUR_DEVICE_UID', ipcon);

 This object can then be used after the IP Connection is connected
 (see examples :ref:`above <barometer_bricklet_delphi_examples>`).


.. delphi:function:: function TBrickletBarometer.GetAirPressure(): longint

 Returns the air pressure of the air pressure sensor. The value
 has a range of 10000 to 1200000 and is given in mbar/1000, i.e. a value
 of 1001092 means that an air pressure of 1001.092 mbar is measured.
 
 If you want to get the air pressure periodically, it is recommended to use the
 callback :delphi:func:`OnAirPressure <TBrickletBarometer.OnAirPressure>` and set the period with
 :delphi:func:`SetAirPressureCallbackPeriod <TBrickletBarometer.SetAirPressureCallbackPeriod>`.
 
.. delphi:function:: function TBrickletBarometer.GetAltitude(): longint

 Returns the relative altitude of the air pressure sensor. The value is given in
 cm and is calculated based on the difference between the current air pressure
 and the reference air pressure that can be set with :delphi:func:`SetReferenceAirPressure <TBrickletBarometer.SetReferenceAirPressure>`.
 
 If you want to get the altitude periodically, it is recommended to use the
 callback :delphi:func:`OnAltitude <TBrickletBarometer.OnAltitude>` and set the period with
 :delphi:func:`SetAltitudeCallbackPeriod <TBrickletBarometer.SetAltitudeCallbackPeriod>`.
 
.. delphi:function:: procedure TBrickletBarometer.SetReferenceAirPressure(const airPressure: longint)

 Sets the reference air pressure in mbar/1000 for the altitude calculation.
 Setting the reference to the current air pressure results in a calculated
 altitude of 0cm. Passing 0 is a shortcut for passing the current air pressure as
 reference.
 
 Well known reference values are the Q codes
 `QNH <http://en.wikipedia.org/wiki/QNH>`__ and
 `QFE <http://en.wikipedia.org/wiki/Mean_sea_level_pressure#Mean_sea_level_pressure>`__
 used in aviation.
 
 The default value is 1013.25mbar.
 
.. delphi:function:: function TBrickletBarometer.GetReferenceAirPressure(): longint

 Returns the reference air pressure as set by :delphi:func:`SetReferenceAirPressure <TBrickletBarometer.SetReferenceAirPressure>`.
 


Advanced Functions
^^^^^^^^^^^^^^^^^^

.. delphi:function:: function TBrickletBarometer.GetChipTemperature(): smallint

 Returns the temperature of the air pressure sensor. The value
 has a range of -4000 to 8500 and is given in °C/100, i.e. a value
 of 2007 means that a temperature of 20.07 °C is measured.
 
 This temperature is used internally for temperature compensation of the air
 pressure measurement. It is not as accurate as the temperature measured by the
 :ref:`temperature_bricklet` or the :ref:`temperature_ir_bricklet`.
 
.. delphi:function:: procedure TBrickletBarometer.SetAveraging(const movingAveragePressure: byte; const averagePressure: byte; const averageTemperature: byte)

 Sets the different averaging parameters. It is possible to set
 the length of a normal averaging for the temperature and pressure,
 as well as an additional length of a 
 `moving average <http://en.wikipedia.org/wiki/Moving_average>`__ 
 for the pressure. The moving average is calculated from the normal 
 averages.  There is no moving average for the temperature.
 
 The maximum length for the pressure average is 10, for the
 temperature average is 255 and for the moving average is 25.
 
 Setting the all three parameters to 0 will turn the averaging
 completely off. If the averaging is off, there is lots of noise
 on the data, but the data is without delay. Thus we recommend
 to turn the averaging off if the Barometer Bricklet data is
 to be used for sensor fusion with other sensors.
 
 The default values are 10 for the normal averages and 25 for the
 moving average.
 
 .. versionadded:: 2.0.1~(Plugin)
 
.. delphi:function:: procedure TBrickletBarometer.GetAveraging(out movingAveragePressure: byte; out averagePressure: byte; out averageTemperature: byte)

 Returns the averaging configuration as set by :delphi:func:`SetAveraging <TBrickletBarometer.SetAveraging>`.
 
 .. versionadded:: 2.0.1~(Plugin)
 
.. delphi:function:: function TBrickletBarometer.GetAPIVersion(): array [0..2] of byte

 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.
 
.. delphi:function:: function TBrickletBarometer.GetResponseExpected(const functionId: byte): 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 callback configuration
 functions it is enabled by default too, but can be disabled by
 :delphi:func:`SetResponseExpected <TBrickletBarometer.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 :delphi:func:`SetResponseExpected <TBrickletBarometer.SetResponseExpected>`
 for the list of function ID constants available for this function.
 
.. delphi:function:: procedure TBrickletBarometer.SetResponseExpected(const functionId: byte; const responseExpected: 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 callback configuration functions (default value: *true*). For
 getter functions it is always enabled and callbacks it is always disabled.
 
 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:
 
 * BRICKLET_BAROMETER_FUNCTION_SET_AIR_PRESSURE_CALLBACK_PERIOD = 3
 * BRICKLET_BAROMETER_FUNCTION_SET_ALTITUDE_CALLBACK_PERIOD = 5
 * BRICKLET_BAROMETER_FUNCTION_SET_AIR_PRESSURE_CALLBACK_THRESHOLD = 7
 * BRICKLET_BAROMETER_FUNCTION_SET_ALTITUDE_CALLBACK_THRESHOLD = 9
 * BRICKLET_BAROMETER_FUNCTION_SET_DEBOUNCE_PERIOD = 11
 * BRICKLET_BAROMETER_FUNCTION_SET_REFERENCE_AIR_PRESSURE = 13
 * BRICKLET_BAROMETER_FUNCTION_SET_AVERAGING = 20
 
.. delphi:function:: procedure TBrickletBarometer.SetResponseExpectedAll(const responseExpected: boolean)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. delphi:function:: procedure TBrickletBarometer.GetIdentity(out uid: string; out connectedUid: string; out position: char; out hardwareVersion: array [0..2] of byte; out firmwareVersion: array [0..2] of byte; out deviceIdentifier: word)

 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 :ref:`here <device_identifier>`.
 |device_identifier_constant|
 


Callback Configuration Functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. delphi:function:: procedure TBrickletBarometer.SetAirPressureCallbackPeriod(const period: longword)

 Sets the period in ms with which the :delphi:func:`OnAirPressure <TBrickletBarometer.OnAirPressure>` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :delphi:func:`OnAirPressure <TBrickletBarometer.OnAirPressure>` is only triggered if the air pressure has changed since the
 last triggering.
 
 The default value is 0.
 
.. delphi:function:: function TBrickletBarometer.GetAirPressureCallbackPeriod(): longword

 Returns the period as set by :delphi:func:`SetAirPressureCallbackPeriod <TBrickletBarometer.SetAirPressureCallbackPeriod>`.
 
.. delphi:function:: procedure TBrickletBarometer.SetAltitudeCallbackPeriod(const period: longword)

 Sets the period in ms with which the :delphi:func:`OnAltitude <TBrickletBarometer.OnAltitude>` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :delphi:func:`OnAltitude <TBrickletBarometer.OnAltitude>` is only triggered if the altitude has changed since the
 last triggering.
 
 The default value is 0.
 
.. delphi:function:: function TBrickletBarometer.GetAltitudeCallbackPeriod(): longword

 Returns the period as set by :delphi:func:`SetAltitudeCallbackPeriod <TBrickletBarometer.SetAltitudeCallbackPeriod>`.
 
.. delphi:function:: procedure TBrickletBarometer.SetAirPressureCallbackThreshold(const option: char; const min: longint; const max: longint)

 Sets the thresholds for the :delphi:func:`OnAirPressureReached <TBrickletBarometer.OnAirPressureReached>` callback.
 
 The following options are possible:
 
 .. csv-table::
  :header: "Option", "Description"
  :widths: 10, 100
 
  "'x'",    "Callback is turned off"
  "'o'",    "Callback is triggered when the air pressure is *outside* the min and max values"
  "'i'",    "Callback is triggered when the air pressure is *inside* the min and max values"
  "'<'",    "Callback is triggered when the air pressure is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the air pressure is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0).
 
 The following constants are available for this function:
 
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OFF = 'x'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_INSIDE = 'i'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_SMALLER = '<'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_GREATER = '>'
 
.. delphi:function:: procedure TBrickletBarometer.GetAirPressureCallbackThreshold(out option: char; out min: longint; out max: longint)

 Returns the threshold as set by :delphi:func:`SetAirPressureCallbackThreshold <TBrickletBarometer.SetAirPressureCallbackThreshold>`.
 
 The following constants are available for this function:
 
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OFF = 'x'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_INSIDE = 'i'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_SMALLER = '<'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_GREATER = '>'
 
.. delphi:function:: procedure TBrickletBarometer.SetAltitudeCallbackThreshold(const option: char; const min: longint; const max: longint)

 Sets the thresholds for the :delphi:func:`OnAltitudeReached <TBrickletBarometer.OnAltitudeReached>` callback.
 
 The following options are possible:
 
 .. csv-table::
  :header: "Option", "Description"
  :widths: 10, 100
 
  "'x'",    "Callback is turned off"
  "'o'",    "Callback is triggered when the altitude is *outside* the min and max values"
  "'i'",    "Callback is triggered when the altitude is *inside* the min and max values"
  "'<'",    "Callback is triggered when the altitude is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the altitude is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0).
 
 The following constants are available for this function:
 
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OFF = 'x'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_INSIDE = 'i'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_SMALLER = '<'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_GREATER = '>'
 
.. delphi:function:: procedure TBrickletBarometer.GetAltitudeCallbackThreshold(out option: char; out min: longint; out max: longint)

 Returns the threshold as set by :delphi:func:`SetAltitudeCallbackThreshold <TBrickletBarometer.SetAltitudeCallbackThreshold>`.
 
 The following constants are available for this function:
 
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OFF = 'x'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_INSIDE = 'i'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_SMALLER = '<'
 * BRICKLET_BAROMETER_THRESHOLD_OPTION_GREATER = '>'
 
.. delphi:function:: procedure TBrickletBarometer.SetDebouncePeriod(const debounce: longword)

 Sets the period in ms with which the threshold callbacks
 
 * :delphi:func:`OnAirPressureReached <TBrickletBarometer.OnAirPressureReached>`,
 * :delphi:func:`OnAltitudeReached <TBrickletBarometer.OnAltitudeReached>`
 
 are triggered, if the thresholds
 
 * :delphi:func:`SetAirPressureCallbackThreshold <TBrickletBarometer.SetAirPressureCallbackThreshold>`,
 * :delphi:func:`SetAltitudeCallbackThreshold <TBrickletBarometer.SetAltitudeCallbackThreshold>`
 
 keep being reached.
 
 The default value is 100.
 
.. delphi:function:: function TBrickletBarometer.GetDebouncePeriod(): longword

 Returns the debounce period as set by :delphi:func:`SetDebouncePeriod <TBrickletBarometer.SetDebouncePeriod>`.
 




.. _barometer_bricklet_delphi_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive time critical or recurring data from
the device. The registration is done by assigning a procedure to an callback
property of the device object:

 .. code-block:: delphi

  procedure TExample.MyCallback(sender: TBrickletBarometer; const param: word);
  begin
    WriteLn(param);
  end;

  barometer.OnExample := {$ifdef FPC}@{$endif}example.MyCallback;

The available callback property and their 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.

.. delphi:function:: property TBrickletBarometer.OnAirPressure

 .. code-block:: delphi

  procedure(sender: TBrickletBarometer; const airPressure: longint) of object;


 This callback is triggered periodically with the period that is set by
 :delphi:func:`SetAirPressureCallbackPeriod <TBrickletBarometer.SetAirPressureCallbackPeriod>`. The parameter is the air pressure of the
 air pressure sensor.
 
 :delphi:func:`OnAirPressure <TBrickletBarometer.OnAirPressure>` is only triggered if the air pressure has changed since the
 last triggering.
 
.. delphi:function:: property TBrickletBarometer.OnAltitude

 .. code-block:: delphi

  procedure(sender: TBrickletBarometer; const altitude: longint) of object;


 This callback is triggered periodically with the period that is set by
 :delphi:func:`SetAltitudeCallbackPeriod <TBrickletBarometer.SetAltitudeCallbackPeriod>`. The parameter is the altitude of the
 air pressure sensor.
 
 :delphi:func:`OnAltitude <TBrickletBarometer.OnAltitude>` is only triggered if the altitude has changed since the
 last triggering.
 
.. delphi:function:: property TBrickletBarometer.OnAirPressureReached

 .. code-block:: delphi

  procedure(sender: TBrickletBarometer; const airPressure: longint) of object;


 This callback is triggered when the threshold as set by
 :delphi:func:`SetAirPressureCallbackThreshold <TBrickletBarometer.SetAirPressureCallbackThreshold>` is reached.
 The parameter is the air pressure of the air pressure sensor.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :delphi:func:`SetDebouncePeriod <TBrickletBarometer.SetDebouncePeriod>`.
 
.. delphi:function:: property TBrickletBarometer.OnAltitudeReached

 .. code-block:: delphi

  procedure(sender: TBrickletBarometer; const altitude: longint) of object;


 This callback is triggered when the threshold as set by
 :delphi:func:`SetAltitudeCallbackThreshold <TBrickletBarometer.SetAltitudeCallbackThreshold>` is reached.
 The parameter is the altitude of the air pressure sensor.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :delphi:func:`SetDebouncePeriod <TBrickletBarometer.SetDebouncePeriod>`.
 


.. _barometer_bricklet_delphi_constants:

Constants
^^^^^^^^^

.. delphi:function:: const BRICKLET_BAROMETER_DEVICE_IDENTIFIER

 This constant is used to identify a Barometer Bricklet.

 The :delphi:func:`GetIdentity <TBrickletBarometer.GetIdentity>` function and the
 :delphi:func:`OnEnumerate <TIPConnection.OnEnumerate>`
 callback of the IP Connection have a ``deviceIdentifier`` parameter to specify
 the Brick's or Bricklet's type.

