..
 #############################################################
 # 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  #
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:breadcrumbs: <a href="../../index.html">Home</a> / <a href="../../index.html#software-c">Software</a> / C/C++ - Master Brick

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

.. _master_brick_c:

C/C++ - Master Brick
====================

This is the description of the :ref:`C/C++ API bindings <api_bindings_c>` for the :ref:`Master Brick <master_brick>`. General information and technical
specifications for the Master Brick are summarized in its :ref:`hardware description
<master_brick_description>`.

An :ref:`installation guide <api_bindings_c_install>` for the C/C++ API
bindings is part of their general description.

.. _master_brick_c_examples:


Examples
--------

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

Stack Status
^^^^^^^^^^^^

`Download (example_stack_status.c) <https://github.com/Tinkerforge/master-brick/raw/master/software/examples/c/example_stack_status.c>`__

.. literalinclude:: Master_Brick_C_example_stack_status.c
 :language: c
 :linenos:
 :tab-width: 4

.. _master_brick_c_api:

API
---

Every function of the C/C++ bindings returns an integer which describes an
error code. Data returned from the device, when a getter is called,
is handled via call by reference. These parameters are labeled with the
``ret_`` prefix.

Possible error codes are:

* E_OK = 0
* E_TIMEOUT = -1
* E_NO_STREAM_SOCKET = -2
* E_HOSTNAME_INVALID = -3
* E_NO_CONNECT = -4
* E_NO_THREAD = -5
* E_NOT_ADDED = -6 (unused since bindings version 2.0.0)
* E_ALREADY_CONNECTED = -7
* E_NOT_CONNECTED = -8
* E_INVALID_PARAMETER = -9
* E_NOT_SUPPORTED = -10
* E_UNKNOWN_ERROR_CODE = -11

as defined in :file:`ip_connection.h`.

All functions listed below are thread-safe.




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


.. c:function:: void master_create(Master *master, const char *uid, IPConnection *ipcon)

 Creates the device object ``master`` with the unique device ID ``uid`` and adds
 it to the IPConnection ``ipcon``:

 .. code-block:: c

    Master master;
    master_create(&master, "YOUR_DEVICE_UID", &ipcon);

 This device object can be used after the IP connection has been connected
 (see examples :ref:`above <master_brick_c_examples>`).

.. c:function:: void master_destroy(Master *master)

 Removes the device object ``master`` from its IPConnection and destroys it.
 The device object cannot be used anymore afterwards.


.. c:function:: int master_get_stack_voltage(Master *master, uint16_t *ret_voltage)

 Returns the stack voltage in mV. The stack voltage is the
 voltage that is supplied via the stack, i.e. it is given by a 
 Step-Down or Step-Up Power Supply.
 
.. c:function:: int master_get_stack_current(Master *master, uint16_t *ret_current)

 Returns the stack current in mA. The stack current is the
 current that is drawn via the stack, i.e. it is given by a
 Step-Down or Step-Up Power Supply.
 


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

.. c:function:: int master_set_extension_type(Master *master, uint8_t extension, uint32_t exttype)

 Writes the extension type to the EEPROM of a specified extension. 
 The extension is either 0 or 1 (0 is the on the bottom, 1 is the on on top, 
 if only one extension is present use 0).
 
 Possible extension types:
 
 .. csv-table::
  :header: "Type", "Description"
  :widths: 10, 100
 
  "1",    "Chibi"
  "2",    "RS485"
  "3",    "WIFI"
  "4",    "Ethernet"
 
 The extension type is already set when bought and it can be set with the 
 Brick Viewer, it is unlikely that you need this function.
 
 The following defines are available for this function:
 
 * MASTER_EXTENSION_TYPE_CHIBI = 1
 * MASTER_EXTENSION_TYPE_RS485 = 2
 * MASTER_EXTENSION_TYPE_WIFI = 3
 * MASTER_EXTENSION_TYPE_ETHERNET = 4
 
.. c:function:: int master_get_extension_type(Master *master, uint8_t extension, uint32_t *ret_exttype)

 Returns the type for a given extension as set by :c:func:`master_set_extension_type`.
 
 The following defines are available for this function:
 
 * MASTER_EXTENSION_TYPE_CHIBI = 1
 * MASTER_EXTENSION_TYPE_RS485 = 2
 * MASTER_EXTENSION_TYPE_WIFI = 3
 * MASTER_EXTENSION_TYPE_ETHERNET = 4
 
.. c:function:: int master_is_chibi_present(Master *master, bool *ret_present)

 Returns *true* if a Chibi Extension is available to be used by the Master Brick.
 
.. c:function:: int master_set_chibi_address(Master *master, uint8_t address)

 Sets the address (1-255) belonging to the Chibi Extension.
 
 It is possible to set the address with the Brick Viewer and it will be 
 saved in the EEPROM of the Chibi Extension, it does not
 have to be set on every startup.
 
.. c:function:: int master_get_chibi_address(Master *master, uint8_t *ret_address)

 Returns the address as set by :c:func:`master_set_chibi_address`.
 
.. c:function:: int master_set_chibi_master_address(Master *master, uint8_t address)

 Sets the address (1-255) of the Chibi Master. This address is used if the
 Chibi Extension is used as slave (i.e. it does not have a USB connection).
 
 It is possible to set the address with the Brick Viewer and it will be 
 saved in the EEPROM of the Chibi Extension, it does not
 have to be set on every startup.
 
.. c:function:: int master_get_chibi_master_address(Master *master, uint8_t *ret_address)

 Returns the address as set by :c:func:`master_set_chibi_master_address`.
 
.. c:function:: int master_set_chibi_slave_address(Master *master, uint8_t num, uint8_t address)

 Sets up to 254 slave addresses. Valid addresses are in range 1-255. 0 has a
 special meaning, it is used as list terminator and not allowed as normal slave
 address. The address numeration (via ``num`` parameter) has to be used
 ascending from 0. For example: If you use the Chibi Extension in Master mode
 (i.e. the stack has an USB connection) and you want to talk to three other
 Chibi stacks with the slave addresses 17, 23, and 42, you should call with
 ``(0, 17)``, ``(1, 23)``, ``(2, 42)`` and ``(3, 0)``. The last call with
 ``(3, 0)`` is a list terminator and indicates that the Chibi slave address
 list contains 3 addresses in this case.
 
 It is possible to set the addresses with the Brick Viewer, that will take care
 of correct address numeration and list termination.
 
 The slave addresses will be saved in the EEPROM of the Chibi Extension, they
 don't have to be set on every startup.
 
.. c:function:: int master_get_chibi_slave_address(Master *master, uint8_t num, uint8_t *ret_address)

 Returns the slave address for a given ``num`` as set by
 :c:func:`master_set_chibi_slave_address`.
 
.. c:function:: int master_get_chibi_signal_strength(Master *master, uint8_t *ret_signal_strength)

 Returns the signal strength in dBm. The signal strength updates every time a
 packet is received.
 
.. c:function:: int master_get_chibi_error_log(Master *master, uint16_t *ret_underrun, uint16_t *ret_crc_error, uint16_t *ret_no_ack, uint16_t *ret_overflow)

 Returns underrun, CRC error, no ACK and overflow error counts of the Chibi
 communication. If these errors start rising, it is likely that either the
 distance between two Chibi stacks is becoming too big or there are
 interferences.
 
.. c:function:: int master_set_chibi_frequency(Master *master, uint8_t frequency)

 Sets the Chibi frequency range for the Chibi Extension. Possible values are:
 
 .. csv-table::
  :header: "Type", "Description"
  :widths: 10, 100
 
  "0",    "OQPSK 868MHz (Europe)"
  "1",    "OQPSK 915MHz (US)"
  "2",    "OQPSK 780MHz (China)"
  "3",    "BPSK40 915MHz"
 
 It is possible to set the frequency with the Brick Viewer and it will be 
 saved in the EEPROM of the Chibi Extension, it does not
 have to be set on every startup.
 
 The following defines are available for this function:
 
 * MASTER_CHIBI_FREQUENCY_OQPSK_868_MHZ = 0
 * MASTER_CHIBI_FREQUENCY_OQPSK_915_MHZ = 1
 * MASTER_CHIBI_FREQUENCY_OQPSK_780_MHZ = 2
 * MASTER_CHIBI_FREQUENCY_BPSK40_915_MHZ = 3
 
.. c:function:: int master_get_chibi_frequency(Master *master, uint8_t *ret_frequency)

 Returns the frequency value as set by :c:func:`master_set_chibi_frequency`.
 
 The following defines are available for this function:
 
 * MASTER_CHIBI_FREQUENCY_OQPSK_868_MHZ = 0
 * MASTER_CHIBI_FREQUENCY_OQPSK_915_MHZ = 1
 * MASTER_CHIBI_FREQUENCY_OQPSK_780_MHZ = 2
 * MASTER_CHIBI_FREQUENCY_BPSK40_915_MHZ = 3
 
.. c:function:: int master_set_chibi_channel(Master *master, uint8_t channel)

 Sets the channel used by the Chibi Extension. Possible channels are
 different for different frequencies:
 
 .. csv-table::
  :header: "Frequency",             "Possible Channels"
  :widths: 40, 60
 
  "OQPSK 868MHz (Europe)", "0"
  "OQPSK 915MHz (US)",     "1, 2, 3, 4, 5, 6, 7, 8, 9, 10"
  "OQPSK 780MHz (China)",  "0, 1, 2, 3"
  "BPSK40 915MHz",         "1, 2, 3, 4, 5, 6, 7, 8, 9, 10"
 
 It is possible to set the channel with the Brick Viewer and it will be 
 saved in the EEPROM of the Chibi Extension, it does not
 have to be set on every startup.
 
.. c:function:: int master_get_chibi_channel(Master *master, uint8_t *ret_channel)

 Returns the channel as set by :c:func:`master_set_chibi_channel`.
 
.. c:function:: int master_is_rs485_present(Master *master, bool *ret_present)

 Returns *true* if a RS485 Extension is available to be used by the Master Brick.
 
.. c:function:: int master_set_rs485_address(Master *master, uint8_t address)

 Sets the address (0-255) belonging to the RS485 Extension.
 
 Set to 0 if the RS485 Extension should be the RS485 Master (i.e.
 connected to a PC via USB).
 
 It is possible to set the address with the Brick Viewer and it will be 
 saved in the EEPROM of the RS485 Extension, it does not
 have to be set on every startup.
 
.. c:function:: int master_get_rs485_address(Master *master, uint8_t *ret_address)

 Returns the address as set by :c:func:`master_set_rs485_address`.
 
.. c:function:: int master_set_rs485_slave_address(Master *master, uint8_t num, uint8_t address)

 Sets up to 255 slave addresses. Valid addresses are in range 1-255. 0 has a
 special meaning, it is used as list terminator and not allowed as normal slave
 address. The address numeration (via ``num`` parameter) has to be used
 ascending from 0. For example: If you use the RS485 Extension in Master mode
 (i.e. the stack has an USB connection) and you want to talk to three other
 RS485 stacks with the addresses 17, 23, and 42, you should call with
 ``(0, 17)``, ``(1, 23)``, ``(2, 42)`` and ``(3, 0)``. The last call with
 ``(3, 0)`` is a list terminator and indicates that the RS485 slave address list
 contains 3 addresses in this case.
 
 It is possible to set the addresses with the Brick Viewer, that will take care
 of correct address numeration and list termination.
 
 The slave addresses will be saved in the EEPROM of the Chibi Extension, they
 don't have to be set on every startup.
 
.. c:function:: int master_get_rs485_slave_address(Master *master, uint8_t num, uint8_t *ret_address)

 Returns the slave address for a given ``num`` as set by
 :c:func:`master_set_rs485_slave_address`.
 
.. c:function:: int master_get_rs485_error_log(Master *master, uint16_t *ret_crc_error)

 Returns CRC error counts of the RS485 communication.
 If this counter starts rising, it is likely that the distance
 between the RS485 nodes is too big or there is some kind of
 interference.
 
.. c:function:: int master_set_rs485_configuration(Master *master, uint32_t speed, char parity, uint8_t stopbits)

 Sets the configuration of the RS485 Extension. Speed is given in baud. The
 Master Brick will try to match the given baud rate as exactly as possible.
 The maximum recommended baud rate is 2000000 (2Mbit/s).
 Possible values for parity are 'n' (none), 'e' (even) and 'o' (odd).
 Possible values for stop bits are 1 and 2.
 
 If your RS485 is unstable (lost messages etc.), the first thing you should
 try is to decrease the speed. On very large bus (e.g. 1km), you probably
 should use a value in the range of 100000 (100kbit/s).
 
 The values are stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 The following defines are available for this function:
 
 * MASTER_RS485_PARITY_NONE = 'n'
 * MASTER_RS485_PARITY_EVEN = 'e'
 * MASTER_RS485_PARITY_ODD = 'o'
 
.. c:function:: int master_get_rs485_configuration(Master *master, uint32_t *ret_speed, char *ret_parity, uint8_t *ret_stopbits)

 Returns the configuration as set by :c:func:`master_set_rs485_configuration`.
 
 The following defines are available for this function:
 
 * MASTER_RS485_PARITY_NONE = 'n'
 * MASTER_RS485_PARITY_EVEN = 'e'
 * MASTER_RS485_PARITY_ODD = 'o'
 
.. c:function:: int master_is_wifi_present(Master *master, bool *ret_present)

 Returns *true* if a WIFI Extension is available to be used by the Master Brick.
 
.. c:function:: int master_set_wifi_configuration(Master *master, const char ssid[32], uint8_t connection, uint8_t ip[4], uint8_t subnet_mask[4], uint8_t gateway[4], uint16_t port)

 Sets the configuration of the WIFI Extension. The ``ssid`` can have a max length
 of 32 characters. Possible values for ``connection`` are:
 
 .. csv-table::
  :header: "Value", "Description"
  :widths: 10, 90
 
  "0", "DHCP"
  "1", "Static IP"
  "2", "Access Point: DHCP"
  "3", "Access Point: Static IP"
  "4", "Ad Hoc: DHCP"
  "5", "Ad Hoc: Static IP"
 
 If you set ``connection`` to one of the static IP options then you have to
 supply ``ip``, ``subnet_mask`` and ``gateway`` as an array of size 4 (first
 element of the array is the least significant byte of the address). If
 ``connection`` is set to one of the DHCP options then ``ip``, ``subnet_mask``
 and ``gateway`` are ignored, you can set them to 0.
 
 The last parameter is the port that your program will connect to. The
 default port, that is used by brickd, is 4223.
 
 The values are stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 It is recommended to use the Brick Viewer to set the WIFI configuration.
 
 The following defines are available for this function:
 
 * MASTER_WIFI_CONNECTION_DHCP = 0
 * MASTER_WIFI_CONNECTION_STATIC_IP = 1
 * MASTER_WIFI_CONNECTION_ACCESS_POINT_DHCP = 2
 * MASTER_WIFI_CONNECTION_ACCESS_POINT_STATIC_IP = 3
 * MASTER_WIFI_CONNECTION_AD_HOC_DHCP = 4
 * MASTER_WIFI_CONNECTION_AD_HOC_STATIC_IP = 5
 
.. c:function:: int master_get_wifi_configuration(Master *master, char ret_ssid[32], uint8_t *ret_connection, uint8_t ret_ip[4], uint8_t ret_subnet_mask[4], uint8_t ret_gateway[4], uint16_t *ret_port)

 Returns the configuration as set by :c:func:`master_set_wifi_configuration`.
 
 The following defines are available for this function:
 
 * MASTER_WIFI_CONNECTION_DHCP = 0
 * MASTER_WIFI_CONNECTION_STATIC_IP = 1
 * MASTER_WIFI_CONNECTION_ACCESS_POINT_DHCP = 2
 * MASTER_WIFI_CONNECTION_ACCESS_POINT_STATIC_IP = 3
 * MASTER_WIFI_CONNECTION_AD_HOC_DHCP = 4
 * MASTER_WIFI_CONNECTION_AD_HOC_STATIC_IP = 5
 
.. c:function:: int master_set_wifi_encryption(Master *master, uint8_t encryption, const char key[50], uint8_t key_index, uint8_t eap_options, uint16_t ca_certificate_length, uint16_t client_certificate_length, uint16_t private_key_length)

 Sets the encryption of the WIFI Extension. The first parameter is the
 type of the encryption. Possible values are:
 
 .. csv-table::
  :header: "Value", "Description"
  :widths: 10, 90
 
  "0", "WPA/WPA2"
  "1", "WPA Enterprise (EAP-FAST, EAP-TLS, EAP-TTLS, PEAP)"
  "2", "WEP"
  "3", "No Encryption"
 
 The ``key`` has a max length of 50 characters and is used if ``encryption``
 is set to 0 or 2 (WPA/WPA2 or WEP). Otherwise the value is ignored.
 
 For WPA/WPA2 the key has to be at least 8 characters long. If you want to set
 a key with more than 50 characters, see :c:func:`master_set_long_wifi_key`.
 
 For WEP the key has to be either 10 or 26 hexadecimal digits long. It is
 possible to set the WEP ``key_index`` (1-4). If you don't know your
 ``key_index``, it is likely 1.
 
 If you choose WPA Enterprise as encryption, you have to set ``eap_options`` and
 the length of the certificates (for other encryption types these parameters
 are ignored). The certificate length are given in byte and the certificates
 themselves can be set with :c:func:`master_set_wifi_certificate`. ``eap_options`` consist
 of the outer authentication (bits 1-2), inner authentication (bit 3) and
 certificate type (bits 4-5):
 
 .. csv-table::
  :header: "Option", "Bits", "Description"
  :widths: 20, 10, 70
 
  "outer authentication", "1-2", "0=EAP-FAST, 1=EAP-TLS, 2=EAP-TTLS, 3=EAP-PEAP"
  "inner authentication", "3", "0=EAP-MSCHAP, 1=EAP-GTC"
  "certificate type", "4-5", "0=CA Certificate, 1=Client Certificate, 2=Private Key"
 
 Example for EAP-TTLS + EAP-GTC + Private Key: ``option = 2 | (1 << 2) | (2 << 3)``.
 
 The values are stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 It is recommended to use the Brick Viewer to set the Wi-Fi encryption.
 
 The following defines are available for this function:
 
 * MASTER_WIFI_ENCRYPTION_WPA_WPA2 = 0
 * MASTER_WIFI_ENCRYPTION_WPA_ENTERPRISE = 1
 * MASTER_WIFI_ENCRYPTION_WEP = 2
 * MASTER_WIFI_ENCRYPTION_NO_ENCRYPTION = 3
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_FAST = 0
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_TLS = 1
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_TTLS = 2
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_PEAP = 3
 * MASTER_WIFI_EAP_OPTION_INNER_AUTH_EAP_MSCHAP = 0
 * MASTER_WIFI_EAP_OPTION_INNER_AUTH_EAP_GTC = 4
 * MASTER_WIFI_EAP_OPTION_CERT_TYPE_CA_CERT = 0
 * MASTER_WIFI_EAP_OPTION_CERT_TYPE_CLIENT_CERT = 8
 * MASTER_WIFI_EAP_OPTION_CERT_TYPE_PRIVATE_KEY = 16
 
.. c:function:: int master_get_wifi_encryption(Master *master, uint8_t *ret_encryption, char ret_key[50], uint8_t *ret_key_index, uint8_t *ret_eap_options, uint16_t *ret_ca_certificate_length, uint16_t *ret_client_certificate_length, uint16_t *ret_private_key_length)

 Returns the encryption as set by :c:func:`master_set_wifi_encryption`.
 
 The following defines are available for this function:
 
 * MASTER_WIFI_ENCRYPTION_WPA_WPA2 = 0
 * MASTER_WIFI_ENCRYPTION_WPA_ENTERPRISE = 1
 * MASTER_WIFI_ENCRYPTION_WEP = 2
 * MASTER_WIFI_ENCRYPTION_NO_ENCRYPTION = 3
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_FAST = 0
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_TLS = 1
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_TTLS = 2
 * MASTER_WIFI_EAP_OPTION_OUTER_AUTH_EAP_PEAP = 3
 * MASTER_WIFI_EAP_OPTION_INNER_AUTH_EAP_MSCHAP = 0
 * MASTER_WIFI_EAP_OPTION_INNER_AUTH_EAP_GTC = 4
 * MASTER_WIFI_EAP_OPTION_CERT_TYPE_CA_CERT = 0
 * MASTER_WIFI_EAP_OPTION_CERT_TYPE_CLIENT_CERT = 8
 * MASTER_WIFI_EAP_OPTION_CERT_TYPE_PRIVATE_KEY = 16
 
.. c:function:: int master_get_wifi_status(Master *master, uint8_t ret_mac_address[6], uint8_t ret_bssid[6], uint8_t *ret_channel, int16_t *ret_rssi, uint8_t ret_ip[4], uint8_t ret_subnet_mask[4], uint8_t ret_gateway[4], uint32_t *ret_rx_count, uint32_t *ret_tx_count, uint8_t *ret_state)

 Returns the status of the WIFI Extension. The ``state`` is updated automatically,
 all of the other parameters are updated on startup and every time
 :c:func:`master_refresh_wifi_status` is called.
 
 Possible states are:
 
 .. csv-table::
  :header: "State", "Description"
  :widths: 10, 90
 
  "0", "Disassociated"
  "1", "Associated"
  "2", "Associating"
  "3", "Error"
  "255", "Not initialized yet"
 
 The following defines are available for this function:
 
 * MASTER_WIFI_STATE_DISASSOCIATED = 0
 * MASTER_WIFI_STATE_ASSOCIATED = 1
 * MASTER_WIFI_STATE_ASSOCIATING = 2
 * MASTER_WIFI_STATE_ERROR = 3
 * MASTER_WIFI_STATE_NOT_INITIALIZED_YET = 255
 
.. c:function:: int master_refresh_wifi_status(Master *master)

 Refreshes the Wi-Fi status (see :c:func:`master_get_wifi_status`). To read the status
 of the Wi-Fi module, the Master Brick has to change from data mode to
 command mode and back. This transaction and the readout itself is
 unfortunately time consuming. This means, that it might take some ms
 until the stack with attached WIFI Extension reacts again after this
 function is called.
 
.. c:function:: int master_set_wifi_certificate(Master *master, uint16_t index, uint8_t data[32], uint8_t data_length)

 This function is used to set the certificate as well as password and username
 for WPA Enterprise. To set the username use index 0xFFFF,
 to set the password use index 0xFFFE. The max length of username and 
 password is 32.
 
 The certificate is written in chunks of size 32 and the index is used as
 the index of the chunk. ``data_length`` should nearly always be 32. Only
 the last chunk can have a length that is not equal to 32.
 
 The starting index of the CA Certificate is 0, of the Client Certificate
 10000 and for the Private Key 20000. Maximum sizes are 1312, 1312 and
 4320 byte respectively.
 
 The values are stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after uploading the certificate.
 
 It is recommended to use the Brick Viewer to set the certificate, username
 and password.
 
.. c:function:: int master_get_wifi_certificate(Master *master, uint16_t index, uint8_t ret_data[32], uint8_t *ret_data_length)

 Returns the certificate for a given index as set by :c:func:`master_set_wifi_certificate`.
 
.. c:function:: int master_set_wifi_power_mode(Master *master, uint8_t mode)

 Sets the power mode of the WIFI Extension. Possible modes are:
 
 .. csv-table::
  :header: "Mode", "Description"
  :widths: 10, 90
 
  "0", "Full Speed (high power consumption, high throughput)"
  "1", "Low Power (low power consumption, low throughput)"
 
 The default value is 0 (Full Speed).
 
 The following defines are available for this function:
 
 * MASTER_WIFI_POWER_MODE_FULL_SPEED = 0
 * MASTER_WIFI_POWER_MODE_LOW_POWER = 1
 
.. c:function:: int master_get_wifi_power_mode(Master *master, uint8_t *ret_mode)

 Returns the power mode as set by :c:func:`master_set_wifi_power_mode`.
 
 The following defines are available for this function:
 
 * MASTER_WIFI_POWER_MODE_FULL_SPEED = 0
 * MASTER_WIFI_POWER_MODE_LOW_POWER = 1
 
.. c:function:: int master_get_wifi_buffer_info(Master *master, uint32_t *ret_overflow, uint16_t *ret_low_watermark, uint16_t *ret_used)

 Returns informations about the Wi-Fi receive buffer. The Wi-Fi
 receive buffer has a max size of 1500 byte and if data is transfered
 too fast, it might overflow.
 
 The return values are the number of overflows, the low watermark 
 (i.e. the smallest number of bytes that were free in the buffer) and
 the bytes that are currently used.
 
 You should always try to keep the buffer empty, otherwise you will
 have a permanent latency. A good rule of thumb is, that you can transfer
 1000 messages per second without problems.
 
 Try to not send more then 50 messages at a time without any kind of
 break between them.
 
.. c:function:: int master_set_wifi_regulatory_domain(Master *master, uint8_t domain)

 Sets the regulatory domain of the WIFI Extension. Possible domains are:
 
 .. csv-table::
  :header: "Domain", "Description"
  :widths: 10, 90
 
  "0", "FCC: Channel 1-11 (N/S America, Australia, New Zealand)"
  "1", "ETSI: Channel 1-13 (Europe, Middle East, Africa)"
  "2", "TELEC: Channel 1-14 (Japan)"
 
 The default value is 1 (ETSI).
 
 The following defines are available for this function:
 
 * MASTER_WIFI_DOMAIN_CHANNEL_1TO11 = 0
 * MASTER_WIFI_DOMAIN_CHANNEL_1TO13 = 1
 * MASTER_WIFI_DOMAIN_CHANNEL_1TO14 = 2
 
.. c:function:: int master_get_wifi_regulatory_domain(Master *master, uint8_t *ret_domain)

 Returns the regulatory domain as set by :c:func:`master_set_wifi_regulatory_domain`.
 
 The following defines are available for this function:
 
 * MASTER_WIFI_DOMAIN_CHANNEL_1TO11 = 0
 * MASTER_WIFI_DOMAIN_CHANNEL_1TO13 = 1
 * MASTER_WIFI_DOMAIN_CHANNEL_1TO14 = 2
 
.. c:function:: int master_get_usb_voltage(Master *master, uint16_t *ret_voltage)

 Returns the USB voltage in mV. Does not work with hardware version 2.1.
 
.. c:function:: int master_set_long_wifi_key(Master *master, const char key[64])

 Sets a long Wi-Fi key (up to 63 chars, at least 8 chars) for WPA encryption.
 This key will be used
 if the key in :c:func:`master_set_wifi_encryption` is set to "-". In the old protocol,
 a payload of size 63 was not possible, so the maximum key length was 50 chars.
 
 With the new protocol this is possible, since we didn't want to break API,
 this function was added additionally.
 
 .. versionadded:: 2.0.2~(Firmware)
 
.. c:function:: int master_get_long_wifi_key(Master *master, char ret_key[64])

 Returns the encryption key as set by :c:func:`master_set_long_wifi_key`.
 
 .. versionadded:: 2.0.2~(Firmware)
 
.. c:function:: int master_set_wifi_hostname(Master *master, const char hostname[16])

 Sets the hostname of the WIFI Extension. The hostname will be displayed 
 by access points as the hostname in the DHCP clients table.
 
 Setting an empty String will restore the default hostname.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_wifi_hostname(Master *master, char ret_hostname[16])

 Returns the hostname as set by :c:func:`master_get_wifi_hostname`.
 
 An empty String means, that the default hostname is used.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_is_ethernet_present(Master *master, bool *ret_present)

 Returns *true* if a Ethernet Extension is available to be used by the Master
 Brick.
 
 .. versionadded:: 2.1.0~(Firmware)
 
.. c:function:: int master_set_ethernet_configuration(Master *master, uint8_t connection, uint8_t ip[4], uint8_t subnet_mask[4], uint8_t gateway[4], uint16_t port)

 Sets the configuration of the Ethernet Extension. Possible values for
 ``connection`` are:
 
 .. csv-table::
  :header: "Value", "Description"
  :widths: 10, 90
 
  "0", "DHCP"
  "1", "Static IP"
 
 If you set ``connection`` to static IP options then you have to supply ``ip``,
 ``subnet_mask`` and ``gateway`` as an array of size 4 (first element of the
 array is the least significant byte of the address). If ``connection`` is set
 to the DHCP options then ``ip``, ``subnet_mask`` and ``gateway`` are ignored,
 you can set them to 0.
 
 The last parameter is the port that your program will connect to. The
 default port, that is used by brickd, is 4223.
 
 The values are stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 It is recommended to use the Brick Viewer to set the Ethernet configuration.
 
 The following defines are available for this function:
 
 * MASTER_ETHERNET_CONNECTION_DHCP = 0
 * MASTER_ETHERNET_CONNECTION_STATIC_IP = 1
 
 .. versionadded:: 2.1.0~(Firmware)
 
.. c:function:: int master_get_ethernet_configuration(Master *master, uint8_t *ret_connection, uint8_t ret_ip[4], uint8_t ret_subnet_mask[4], uint8_t ret_gateway[4], uint16_t *ret_port)

 Returns the configuration as set by :c:func:`master_set_ethernet_configuration`.
 
 The following defines are available for this function:
 
 * MASTER_ETHERNET_CONNECTION_DHCP = 0
 * MASTER_ETHERNET_CONNECTION_STATIC_IP = 1
 
 .. versionadded:: 2.1.0~(Firmware)
 
.. c:function:: int master_get_ethernet_status(Master *master, uint8_t ret_mac_address[6], uint8_t ret_ip[4], uint8_t ret_subnet_mask[4], uint8_t ret_gateway[4], uint32_t *ret_rx_count, uint32_t *ret_tx_count, char ret_hostname[32])

 Returns the status of the Ethernet Extension.
 
 ``mac_address``, ``ip``, ``subnet_mask`` and ``gateway`` are given as an array.
 The first element of the array is the least significant byte of the address.
 
 ``rx_count`` and ``tx_count`` are the number of bytes that have been
 received/send since last restart.
 
 ``hostname`` is the currently used hostname.
 
 .. versionadded:: 2.1.0~(Firmware)
 
.. c:function:: int master_set_ethernet_hostname(Master *master, const char hostname[32])

 Sets the hostname of the Ethernet Extension. The hostname will be displayed 
 by access points as the hostname in the DHCP clients table.
 
 Setting an empty String will restore the default hostname.
 
 The current hostname can be discovered with :c:func:`master_get_ethernet_status`.
 
 .. versionadded:: 2.1.0~(Firmware)
 
.. c:function:: int master_set_ethernet_mac_address(Master *master, uint8_t mac_address[6])

 Sets the MAC address of the Ethernet Extension. The Ethernet Extension should
 come configured with a valid MAC address, that is also written on a
 sticker of the extension itself.
 
 The MAC address can be read out again with :c:func:`master_get_ethernet_status`.
 
 .. versionadded:: 2.1.0~(Firmware)
 
.. c:function:: int master_set_ethernet_websocket_configuration(Master *master, uint8_t sockets, uint16_t port)

 Sets the Ethernet WebSocket configuration. The first parameter sets the number of socket
 connections that are reserved for WebSockets. The range is 0-7. The connections
 are shared with the plain sockets. Example: If you set the connections to 3,
 there will be 3 WebSocket and 4 plain socket connections available.
 
 The second parameter is the port for the WebSocket connections. The port can
 not be the same as the port for the plain socket connections.
 
 The values are stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 It is recommended to use the Brick Viewer to set the Ethernet configuration.
 
 The default values are 3 for the socket connections and 4280 for the port.
 
 .. versionadded:: 2.2.0~(Firmware)
 
.. c:function:: int master_get_ethernet_websocket_configuration(Master *master, uint8_t *ret_sockets, uint16_t *ret_port)

 Returns the configuration as set by :c:func:`master_set_ethernet_configuration`.
 
 .. versionadded:: 2.2.0~(Firmware)
 
.. c:function:: int master_set_ethernet_authentication_secret(Master *master, const char secret[64])

 Sets the Ethernet authentication secret. The secret can be a string of up to 64
 characters. An empty string disables the authentication.
 
 See the :ref:`authentication tutorial <tutorial_authentication>` for more
 information.
 
 The secret is stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 It is recommended to use the Brick Viewer to set the Ethernet authentication secret.
 
 The default value is an empty string (authentication disabled).
 
 .. versionadded:: 2.2.0~(Firmware)
 
.. c:function:: int master_get_ethernet_authentication_secret(Master *master, char ret_secret[64])

 Returns the authentication secret as set by :c:func:`master_set_ethernet_authentication_secret`.
 
 .. versionadded:: 2.2.0~(Firmware)
 
.. c:function:: int master_set_wifi_authentication_secret(Master *master, const char secret[64])

 Sets the WIFI authentication secret. The secret can be a string of up to 64
 characters. An empty string disables the authentication.
 
 See the :ref:`authentication tutorial <tutorial_authentication>` for more
 information.
 
 The secret is stored in the EEPROM and only applied on startup. That means
 you have to restart the Master Brick after configuration.
 
 It is recommended to use the Brick Viewer to set the WIFI authentication secret.
 
 The default value is an empty string (authentication disabled).
 
 .. versionadded:: 2.2.0~(Firmware)
 
.. c:function:: int master_get_wifi_authentication_secret(Master *master, char ret_secret[64])

 Returns the authentication secret as set by :c:func:`master_set_wifi_authentication_secret`.
 
 .. versionadded:: 2.2.0~(Firmware)
 
.. c:function:: int master_get_api_version(Master *master, uint8_t ret_api_version[3])

 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.
 
.. c:function:: int master_get_response_expected(Master *master, uint8_t function_id, bool *ret_response_expected)

 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
 :c:func:`master_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.
 
 See :c:func:`master_set_response_expected`
 for the list of function ID defines available for this function.
 
.. c:function:: int master_set_response_expected(Master *master, uint8_t function_id, bool response_expected)

 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 defines are available for this function:
 
 * MASTER_FUNCTION_SET_EXTENSION_TYPE = 3
 * MASTER_FUNCTION_SET_CHIBI_ADDRESS = 6
 * MASTER_FUNCTION_SET_CHIBI_MASTER_ADDRESS = 8
 * MASTER_FUNCTION_SET_CHIBI_SLAVE_ADDRESS = 10
 * MASTER_FUNCTION_SET_CHIBI_FREQUENCY = 14
 * MASTER_FUNCTION_SET_CHIBI_CHANNEL = 16
 * MASTER_FUNCTION_SET_RS485_ADDRESS = 19
 * MASTER_FUNCTION_SET_RS485_SLAVE_ADDRESS = 21
 * MASTER_FUNCTION_SET_RS485_CONFIGURATION = 24
 * MASTER_FUNCTION_SET_WIFI_CONFIGURATION = 27
 * MASTER_FUNCTION_SET_WIFI_ENCRYPTION = 29
 * MASTER_FUNCTION_REFRESH_WIFI_STATUS = 32
 * MASTER_FUNCTION_SET_WIFI_CERTIFICATE = 33
 * MASTER_FUNCTION_SET_WIFI_POWER_MODE = 35
 * MASTER_FUNCTION_SET_WIFI_REGULATORY_DOMAIN = 38
 * MASTER_FUNCTION_SET_LONG_WIFI_KEY = 41
 * MASTER_FUNCTION_SET_WIFI_HOSTNAME = 43
 * MASTER_FUNCTION_SET_STACK_CURRENT_CALLBACK_PERIOD = 45
 * MASTER_FUNCTION_SET_STACK_VOLTAGE_CALLBACK_PERIOD = 47
 * MASTER_FUNCTION_SET_USB_VOLTAGE_CALLBACK_PERIOD = 49
 * MASTER_FUNCTION_SET_STACK_CURRENT_CALLBACK_THRESHOLD = 51
 * MASTER_FUNCTION_SET_STACK_VOLTAGE_CALLBACK_THRESHOLD = 53
 * MASTER_FUNCTION_SET_USB_VOLTAGE_CALLBACK_THRESHOLD = 55
 * MASTER_FUNCTION_SET_DEBOUNCE_PERIOD = 57
 * MASTER_FUNCTION_SET_ETHERNET_CONFIGURATION = 66
 * MASTER_FUNCTION_SET_ETHERNET_HOSTNAME = 69
 * MASTER_FUNCTION_SET_ETHERNET_MAC_ADDRESS = 70
 * MASTER_FUNCTION_SET_ETHERNET_WEBSOCKET_CONFIGURATION = 71
 * MASTER_FUNCTION_SET_ETHERNET_AUTHENTICATION_SECRET = 73
 * MASTER_FUNCTION_SET_WIFI_AUTHENTICATION_SECRET = 75
 * MASTER_FUNCTION_ENABLE_STATUS_LED = 238
 * MASTER_FUNCTION_DISABLE_STATUS_LED = 239
 * MASTER_FUNCTION_RESET = 243
 
.. c:function:: int master_set_response_expected_all(Master *master, bool response_expected)

 Changes the response expected flag for all setter and callback configuration
 functions of this device at once.
 
.. c:function:: int master_enable_status_led(Master *master)

 Enables the status LED.
 
 The status LED is the blue LED next to the USB connector. If enabled is is
 on and it flickers if data is transfered. If disabled it is always off.
 
 The default state is enabled.
 
 .. versionadded:: 2.3.2~(Firmware)
 
.. c:function:: int master_disable_status_led(Master *master)

 Disables the status LED.
 
 The status LED is the blue LED next to the USB connector. If enabled is is
 on and it flickers if data is transfered. If disabled it is always off.
 
 The default state is enabled.
 
 .. versionadded:: 2.3.2~(Firmware)
 
.. c:function:: int master_is_status_led_enabled(Master *master, bool *ret_enabled)

 Returns *true* if the status LED is enabled, *false* otherwise.
 
 .. versionadded:: 2.3.2~(Firmware)
 
.. c:function:: int master_get_protocol1_bricklet_name(Master *master, char port, uint8_t *ret_protocol_version, uint8_t ret_firmware_version[3], char ret_name[40])

 Returns the firmware and protocol version and the name of the Bricklet for a
 given port.
 
 This functions sole purpose is to allow automatic flashing of v1.x.y Bricklet
 plugins.
 
.. c:function:: int master_get_chip_temperature(Master *master, int16_t *ret_temperature)

 Returns the temperature in °C/10 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 an
 accuracy of +-15%. Practically it is only useful as an indicator for
 temperature changes.
 
.. c:function:: int master_reset(Master *master)

 Calling this function will reset the Brick. Calling this function
 on a Brick inside of a stack will reset the whole stack.
 
 After a reset you have to create new device objects,
 calling functions on the existing ones will result in
 undefined behavior!
 
.. c:function:: int master_get_identity(Master *master, char ret_uid[8], char ret_connected_uid[8], char *ret_position, uint8_t ret_hardware_version[3], uint8_t ret_firmware_version[3], uint16_t *ret_device_identifier)

 Returns the UID, the UID where the Brick is connected to, 
 the position, the hardware and firmware version as well as the
 device identifier.
 
 The position can be '0'-'8' (stack position).
 
 The device identifier numbers can be found :ref:`here <device_identifier>`.
 |device_identifier_constant|
 


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


.. c:function:: void master_register_callback(Master *master, uint8_t id, void *callback, void *user_data)

 Registers a callback with ID ``id`` to the function ``callback``. The
 ``user_data`` will be given as a parameter of the callback.

 The available IDs with corresponding function signatures are listed
 :ref:`below <master_brick_c_callbacks>`.


.. c:function:: int master_set_stack_current_callback_period(Master *master, uint32_t period)

 Sets the period in ms with which the :c:data:`MASTER_CALLBACK_STACK_CURRENT` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :c:data:`MASTER_CALLBACK_STACK_CURRENT` is only triggered if the current has changed since the
 last triggering.
 
 The default value is 0.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_stack_current_callback_period(Master *master, uint32_t *ret_period)

 Returns the period as set by :func:`SetCurrentCallbackPeriod`.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_set_stack_voltage_callback_period(Master *master, uint32_t period)

 Sets the period in ms with which the :c:data:`MASTER_CALLBACK_STACK_VOLTAGE` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :c:data:`MASTER_CALLBACK_STACK_VOLTAGE` is only triggered if the voltage has changed since the
 last triggering.
 
 The default value is 0.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_stack_voltage_callback_period(Master *master, uint32_t *ret_period)

 Returns the period as set by :c:func:`master_set_stack_voltage_callback_period`.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_set_usb_voltage_callback_period(Master *master, uint32_t period)

 Sets the period in ms with which the :c:data:`MASTER_CALLBACK_USB_VOLTAGE` callback is triggered
 periodically. A value of 0 turns the callback off.
 
 :c:data:`MASTER_CALLBACK_USB_VOLTAGE` is only triggered if the voltage has changed since the
 last triggering.
 
 The default value is 0.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_usb_voltage_callback_period(Master *master, uint32_t *ret_period)

 Returns the period as set by :c:func:`master_set_usb_voltage_callback_period`.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_set_stack_current_callback_threshold(Master *master, char option, uint16_t min, uint16_t max)

 Sets the thresholds for the :c:data:`MASTER_CALLBACK_STACK_CURRENT_REACHED` 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 current is *outside* the min and max values"
  "'i'",    "Callback is triggered when the current is *inside* the min and max values"
  "'<'",    "Callback is triggered when the current is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the current is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0).
 
 The following defines are available for this function:
 
 * MASTER_THRESHOLD_OPTION_OFF = 'x'
 * MASTER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * MASTER_THRESHOLD_OPTION_INSIDE = 'i'
 * MASTER_THRESHOLD_OPTION_SMALLER = '<'
 * MASTER_THRESHOLD_OPTION_GREATER = '>'
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_stack_current_callback_threshold(Master *master, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

 Returns the threshold as set by :c:func:`master_set_stack_current_callback_threshold`.
 
 The following defines are available for this function:
 
 * MASTER_THRESHOLD_OPTION_OFF = 'x'
 * MASTER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * MASTER_THRESHOLD_OPTION_INSIDE = 'i'
 * MASTER_THRESHOLD_OPTION_SMALLER = '<'
 * MASTER_THRESHOLD_OPTION_GREATER = '>'
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_set_stack_voltage_callback_threshold(Master *master, char option, uint16_t min, uint16_t max)

 Sets the thresholds for the :func:`StackStackVoltageReached` 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 voltage is *outside* the min and max values"
  "'i'",    "Callback is triggered when the voltage is *inside* the min and max values"
  "'<'",    "Callback is triggered when the voltage is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the voltage is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0).
 
 The following defines are available for this function:
 
 * MASTER_THRESHOLD_OPTION_OFF = 'x'
 * MASTER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * MASTER_THRESHOLD_OPTION_INSIDE = 'i'
 * MASTER_THRESHOLD_OPTION_SMALLER = '<'
 * MASTER_THRESHOLD_OPTION_GREATER = '>'
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_stack_voltage_callback_threshold(Master *master, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

 Returns the threshold as set by :c:func:`master_set_stack_voltage_callback_threshold`.
 
 The following defines are available for this function:
 
 * MASTER_THRESHOLD_OPTION_OFF = 'x'
 * MASTER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * MASTER_THRESHOLD_OPTION_INSIDE = 'i'
 * MASTER_THRESHOLD_OPTION_SMALLER = '<'
 * MASTER_THRESHOLD_OPTION_GREATER = '>'
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_set_usb_voltage_callback_threshold(Master *master, char option, uint16_t min, uint16_t max)

 Sets the thresholds for the :c:data:`MASTER_CALLBACK_USB_VOLTAGE_REACHED` 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 voltage is *outside* the min and max values"
  "'i'",    "Callback is triggered when the voltage is *inside* the min and max values"
  "'<'",    "Callback is triggered when the voltage is smaller than the min value (max is ignored)"
  "'>'",    "Callback is triggered when the voltage is greater than the min value (max is ignored)"
 
 The default value is ('x', 0, 0).
 
 The following defines are available for this function:
 
 * MASTER_THRESHOLD_OPTION_OFF = 'x'
 * MASTER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * MASTER_THRESHOLD_OPTION_INSIDE = 'i'
 * MASTER_THRESHOLD_OPTION_SMALLER = '<'
 * MASTER_THRESHOLD_OPTION_GREATER = '>'
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_usb_voltage_callback_threshold(Master *master, char *ret_option, uint16_t *ret_min, uint16_t *ret_max)

 Returns the threshold as set by :c:func:`master_set_usb_voltage_callback_threshold`.
 
 The following defines are available for this function:
 
 * MASTER_THRESHOLD_OPTION_OFF = 'x'
 * MASTER_THRESHOLD_OPTION_OUTSIDE = 'o'
 * MASTER_THRESHOLD_OPTION_INSIDE = 'i'
 * MASTER_THRESHOLD_OPTION_SMALLER = '<'
 * MASTER_THRESHOLD_OPTION_GREATER = '>'
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_set_debounce_period(Master *master, uint32_t debounce)

 Sets the period in ms with which the threshold callbacks
 
 * :c:data:`MASTER_CALLBACK_STACK_CURRENT_REACHED`,
 * :c:data:`MASTER_CALLBACK_STACK_VOLTAGE_REACHED`,
 * :c:data:`MASTER_CALLBACK_USB_VOLTAGE_REACHED`
 
 are triggered, if the thresholds
 
 * :c:func:`master_set_stack_current_callback_threshold`,
 * :c:func:`master_set_stack_voltage_callback_threshold`,
 * :c:func:`master_set_usb_voltage_callback_threshold`
 
 keep being reached.
 
 The default value is 100.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:function:: int master_get_debounce_period(Master *master, uint32_t *ret_debounce)

 Returns the debounce period as set by :c:func:`master_set_debounce_period`.
 
 .. versionadded:: 2.0.5~(Firmware)
 


.. _master_brick_c_callbacks:

Callbacks
^^^^^^^^^

Callbacks can be registered to receive
time critical or recurring data from the device. The registration is done
with the :c:func:`master_register_callback` function. The parameters consist of
the device object, the callback ID, the callback function and optional
user data:

 .. code-block:: c

    void my_callback(int p, void *user_data) {
        printf("parameter: %d\n", p);
    }

    master_register_callback(&master, MASTER_CALLBACK_EXAMPLE, (void *)my_callback, NULL);

The available constants with corresponding callback function signatures
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.

.. c:var:: MASTER_CALLBACK_STACK_CURRENT

 .. code-block:: c

  void callback(uint16_t current, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`master_set_stack_current_callback_period`. The parameter is the current of the
 sensor.
 
 :c:data:`MASTER_CALLBACK_STACK_CURRENT` is only triggered if the current has changed since the
 last triggering.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:var:: MASTER_CALLBACK_STACK_VOLTAGE

 .. code-block:: c

  void callback(uint16_t voltage, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`master_set_stack_voltage_callback_period`. The parameter is the voltage of the
 sensor.
 
 :c:data:`MASTER_CALLBACK_STACK_VOLTAGE` is only triggered if the voltage has changed since the
 last triggering.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:var:: MASTER_CALLBACK_USB_VOLTAGE

 .. code-block:: c

  void callback(uint16_t voltage, void *user_data)


 This callback is triggered periodically with the period that is set by
 :c:func:`master_set_usb_voltage_callback_period`. The parameter is the USB voltage
 in mV.
 
 :c:data:`MASTER_CALLBACK_USB_VOLTAGE` is only triggered if the USB voltage has changed since the
 last triggering.
 
 Does not work with hardware version 2.1.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:var:: MASTER_CALLBACK_STACK_CURRENT_REACHED

 .. code-block:: c

  void callback(uint16_t current, void *user_data)


 This callback is triggered when the threshold as set by
 :c:func:`master_set_stack_current_callback_threshold` is reached.
 The parameter is the stack current in mA.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :c:func:`master_set_debounce_period`.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:var:: MASTER_CALLBACK_STACK_VOLTAGE_REACHED

 .. code-block:: c

  void callback(uint16_t voltage, void *user_data)


 This callback is triggered when the threshold as set by
 :c:func:`master_set_stack_voltage_callback_threshold` is reached.
 The parameter is the stack voltage in mV.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :c:func:`master_set_debounce_period`.
 
 .. versionadded:: 2.0.5~(Firmware)
 
.. c:var:: MASTER_CALLBACK_USB_VOLTAGE_REACHED

 .. code-block:: c

  void callback(uint16_t voltage, void *user_data)


 This callback is triggered when the threshold as set by
 :c:func:`master_set_usb_voltage_callback_threshold` is reached.
 The parameter is the voltage of the sensor.
 
 If the threshold keeps being reached, the callback is triggered periodically
 with the period as set by :c:func:`master_set_debounce_period`.
 
 .. versionadded:: 2.0.5~(Firmware)
 


.. _master_brick_c_constants:

Constants
^^^^^^^^^

.. c:var:: MASTER_DEVICE_IDENTIFIER

 This constant is used to identify a Master Brick.

 The :c:func:`master_get_identity` function and the :c:data:`IPCON_CALLBACK_ENUMERATE`
 callback of the IP Connection have a ``device_identifier`` parameter to specify
 the Brick's or Bricklet's type.

