docs/guides/nrfconnect_examples_configuration.md - third_party/github/project-chip/connectedhomeip - Git at Google

 # Configuring nRF Connect examples

 The nRF Connect example applications all come with a default configuration for
 building. Check the information on this page if you want to modify the
 application configuration or add new functionalities to build your own
 application based on the provided example. This page also contains information
 about the configuration structure, which can be useful to better understand the
 building process.

 <hr>

 ## Configuring application

 Changing the default application configuration can be done either temporarily or
 permanently. Changing configuration temporarily is useful for testing the impact
 of changes on the application behavior. Making permanent changes is better if
 you want to develop your own application, as it helps avoid repeating the
 configuration process.

 <hr>

 ### Temporary changes to configuration

 You can change the configuration temporarily by editing the `.config` file in
 the `build/zephyr/` directory, which stores all configuration options for the
 application generated as a result of the build process. As long as you do not
 remove the current build directory or delete this file, your changes will be
 kept. However, if you do a clean build, your changes are gone, so it is not
 possible to save changes permanently this way.

 Complete the following steps:

 1.  Build the application by typing the following command in the example
     directory, with _build-target_ replaced with the build target name of the
     kit, for example _nrf52840dk_nrf52840_:

          ```
          west build -b build-target
          ```

 2.  Run the terminal-based interface called menuconfig by typing the following
     command:

          ```
          west build -t menuconfig
          ```

     The menuconfig terminal window appears, in which you can navigate using
     arrow keys and other keys, based on the description at the bottom of the
     window.

 3.  Make the desired changes by following the menuconfig terminal instructions.
 4.  Press `Q` to save and quit.
 5.  Rebuild the application.

 At this point, the configuration changes are applied to the output file and it
 can be flashed to the device.

 <hr>

 ### Permanent changes to configuration

 The permanent solution is based on modifying the Kconfig configuration files,
 which are used as components of the building process. This makes the changes
 persistent across builds.

 The best practice to make permanent changes is to edit the main application
 configuration file `prj.conf`, which is located in the example directory. This
 will result in overriding the existing configuration values.

 This method is valid for the majority of cases. If you are interested in
 understanding the big picture of the configuration process, read the
 [Configuration structure overview](#configuration-structure-overview) section
 below.

 #### Assigning values to Kconfig options

 Assigning value to a configuration option is done by typing its full name
 preceded by the `CONFIG_` prefix, and adding the `=` mark and the value.

 Configuration options have different types and it is only possible to assign
 them values of proper type. Few examples:

 -   Assigning logical boolean true value to the option:
     `CONFIG_SAMPLE_BOOLEAN_OPTION=y`
 -   Assigning numeric integer 1234 value to the option:
     `CONFIG_SAMPLE_INTEGER_OPTION=1234`
 -   Assigning text string "some_text" value to the option:
     `CONFIG_SAMPLE_STRING_OPTION="some_text"`

 For more detailed information, read about
 [setting Kconfig values](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/kconfig/setting.html#setting-configuration-values)
 in the nRF Connect SDK documentation.

 Because Kconfig configuration files are used in the building process, make sure
 that you rebuild your application after editing them by typing the following
 command in the example directory, with _build-target_ replaced with the build
 target name of the kit, for example _nrf52840dk_nrf52840_:

         ```
         west build -b build-target
         ```

 <hr>

 ## Configuration structure overview

 Zephyr RTOS and related software components, like drivers and libraries, provide
 a set of Kconfig files which define available configuration options and assign
 them default values for any application.

 The application configuration is specified using Kconfig configuration files
 (`*.conf`), where available Kconfig options can be used and their default values
 overridden. Typically, there are many files having impact on the final
 configuration shape.

 There is no need to modify all these files separately. See the following list
 for types of files you can find in the project and which of them are important
 from your perspective:

 -   **Build target configuration files.** These are hardware-platform-dependent
     configuration files, which are automatically included based on the
     compilation build target name. They contain configuration for the kit and
     its peripherals.

 -   **Project configuration file.** Every example application has its main
     configuration file called `prj.conf` that is located in the example
     directory. This file contains application-specific configuration or the most
     frequently changed options. Almost every configuration can be overridden in
     this file and probably this file is the most important one.

 -   **Overlays.** Overlays are optional files usually used to extract
     configuration for some specific case or feature from the general application
     configuration. The main difference between them and the application
     `prj.conf` file is that they are not included automatically, so you can
     decide whether to build sample with or without them. Overlay files can be
     added to build by typing the following command in the example directory,
     with _build-target_ replaced with the build target name (e.g.
     _nrf52840dk_nrf52840_) and _overlay_file_name_ replaced with the overlay
     configuration file name (e.g. _overlay-usb_support.conf_):

           $ west build -b build-target -- -DOVERLAY_CONFIG=overlay_file_name

 Read the
 [Kconfig](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/kconfig/index.html#kconfig)
 guide in the nRF Connect SDK's Zephyr documentation if you are interested in
 getting more advanced and detailed information about the configuration
 structure.

 <hr>

 ## Configuring Matter in nRF Connect platform

 ### Mandatory configuration

 To use the Matter protocol, you need to set the `CONFIG_CHIP` Kconfig option.
 Setting this option enables the Matter protocol stack and other associated
 Kconfig options, including `CONFIG_CHIP_ENABLE_DNSSD_SRP` that is required for
 the Matter device to be discoverable using DNS-SD.

 After that, make sure to set the `CONFIG_CHIP_PROJECT_CONFIG` Kconfig option and
 define the path to the configuration file that specifies Vendor ID, Product ID,
 and other project-specific Matter settings.

 <hr>

 ### Optional configuration

 After enabling the Matter protocol and defining the path to the Matter
 configuration file, you can enable additional options in Kconfig.

 **Sleepy End Device support**

 You can enable the support for Thread Sleepy End Device in Matter by setting the
 following Kconfig options:

 -   `CONFIG_OPENTHREAD_MTD`
 -   `CONFIG_CHIP_ENABLE_SLEEPY_END_DEVICE_SUPPORT`

 The following Kconfig options can be used to tune Thread Sleepy End Device wake
 intervals:

 -   `CONFIG_CHIP_SED_IDLE_INTERVAL`
 -   `CONFIG_CHIP_SED_ACTIVE_INTERVAL`

 **Commissioning with NFC support**

 You can configure the Matter protocol to use an NFC tag for commissioning,
 instead of using a QR code, which is the default configuration.

 To enable NFC for commissioning and share the onboarding payload in an NFC tag,
 set the `CONFIG_CHIP_NFC_COMMISSIONING` option.

 **Factory reset behavior**

 By default, the factory reset procedure implemented in the Matter stack removes
 Matter-related settings only. If your application does not depend on any
 device-lifelong data stored in the non-volatile storage, set the
 `CONFIG_CHIP_FACTORY_RESET_ERASE_NVS` option to fully erase the NVS partition at
 the factory reset. This approach is more robust and regains the original NVS
 performance in case it has been polluted with unwanted entries.

 **Logging**

 You can enable logging for both the stack and Zephyr’s
 [Logging](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/reference/logging/index.html#logging-api)
 API by setting the `CONFIG_LOG` option.

 Zephyr allows you to configure log levels of different software modules
 independently. To change the log level configuration for the Matter module, set
 one of the available options:

 -   `CONFIG_MATTER_LOG_LEVEL_ERR`
 -   `CONFIG_MATTER_LOG_LEVEL_INFO`
 -   `CONFIG_MATTER_LOG_LEVEL_DBG`

 **Shell**

 You can enable the Matter shell library using the `CONFIG_CHIP_LIB_SHELL`
 Kconfig option. This option lets you use the Matter specific shell commands. See
 [Using CLI in nRF Connect examples](nrfconnect_examples_cli.md) for the list of
 available Matter shell commands.

 **Matter device identification**

 Matter has many mandatory and optional ways to identify a specific device. These
 can be used for various purposes, such as dividing devices into groups (by
 function, by vendor or by location), device commissioning or vendor-specific
 cases before the device was commissioned (for example, identifying factory
 software version or related features).

 Only some part of these features can be configured using Kconfig options and
 only those were listed below:

 -   `CONFIG_CHIP_DEVICE_TYPE` - type of device that uses the Matter Device Type
     Identifier, for example Door Lock (0x000A) or Dimmable Light Bulb (0x0101).
 -   `CONFIG_CHIP_COMMISSIONABLE_DEVICE_TYPE` - enables including optional device
     type subtype in the commissionable node discovery record, which allows
     filtering of the discovery results to find the nodes that match the device
     type.
 -   `CONFIG_CHIP_ROTATING_DEVICE_ID` - enables rotating device identifier, an
     optional feature that provides an additional unique identifier for each
     device. This identifier is similar to the serial number, but it additionally
     changes at predefined times to protect against long-term tracking of the
     device.
	# Configuring nRF Connect examples

	The nRF Connect example applications all come with a default configuration for
	building. Check the information on this page if you want to modify the
	application configuration or add new functionalities to build your own
	application based on the provided example. This page also contains information
	about the configuration structure, which can be useful to better understand the
	building process.

	<hr>

	## Configuring application

	Changing the default application configuration can be done either temporarily or
	permanently. Changing configuration temporarily is useful for testing the impact
	of changes on the application behavior. Making permanent changes is better if
	you want to develop your own application, as it helps avoid repeating the
	configuration process.

	<hr>

	### Temporary changes to configuration

	You can change the configuration temporarily by editing the `.config` file in
	the `build/zephyr/` directory, which stores all configuration options for the
	application generated as a result of the build process. As long as you do not
	remove the current build directory or delete this file, your changes will be
	kept. However, if you do a clean build, your changes are gone, so it is not
	possible to save changes permanently this way.

	Complete the following steps:

	1. Build the application by typing the following command in the example
	directory, with _build-target_ replaced with the build target name of the
	kit, for example _nrf52840dk_nrf52840_:

	```
	west build -b build-target
	```

	2. Run the terminal-based interface called menuconfig by typing the following
	command:

	```
	west build -t menuconfig
	```

	The menuconfig terminal window appears, in which you can navigate using
	arrow keys and other keys, based on the description at the bottom of the
	window.

	3. Make the desired changes by following the menuconfig terminal instructions.
	4. Press `Q` to save and quit.
	5. Rebuild the application.

	At this point, the configuration changes are applied to the output file and it
	can be flashed to the device.

	<hr>

	### Permanent changes to configuration

	The permanent solution is based on modifying the Kconfig configuration files,
	which are used as components of the building process. This makes the changes
	persistent across builds.

	The best practice to make permanent changes is to edit the main application
	configuration file `prj.conf`, which is located in the example directory. This
	will result in overriding the existing configuration values.

	This method is valid for the majority of cases. If you are interested in
	understanding the big picture of the configuration process, read the
	[Configuration structure overview](#configuration-structure-overview) section
	below.

	#### Assigning values to Kconfig options

	Assigning value to a configuration option is done by typing its full name
	preceded by the `CONFIG_` prefix, and adding the `=` mark and the value.

	Configuration options have different types and it is only possible to assign
	them values of proper type. Few examples:

	- Assigning logical boolean true value to the option:
	`CONFIG_SAMPLE_BOOLEAN_OPTION=y`
	- Assigning numeric integer 1234 value to the option:
	`CONFIG_SAMPLE_INTEGER_OPTION=1234`
	- Assigning text string "some_text" value to the option:
	`CONFIG_SAMPLE_STRING_OPTION="some_text"`

	For more detailed information, read about
	[setting Kconfig values](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/kconfig/setting.html#setting-configuration-values)
	in the nRF Connect SDK documentation.

	Because Kconfig configuration files are used in the building process, make sure
	that you rebuild your application after editing them by typing the following
	command in the example directory, with _build-target_ replaced with the build
	target name of the kit, for example _nrf52840dk_nrf52840_:

	```
	west build -b build-target
	```

	<hr>

	## Configuration structure overview

	Zephyr RTOS and related software components, like drivers and libraries, provide
	a set of Kconfig files which define available configuration options and assign
	them default values for any application.

	The application configuration is specified using Kconfig configuration files
	(`*.conf`), where available Kconfig options can be used and their default values
	overridden. Typically, there are many files having impact on the final
	configuration shape.

	There is no need to modify all these files separately. See the following list
	for types of files you can find in the project and which of them are important
	from your perspective:

	- Build target configuration files. These are hardware-platform-dependent
	configuration files, which are automatically included based on the
	compilation build target name. They contain configuration for the kit and
	its peripherals.

	- Project configuration file. Every example application has its main
	configuration file called `prj.conf` that is located in the example
	directory. This file contains application-specific configuration or the most
	frequently changed options. Almost every configuration can be overridden in
	this file and probably this file is the most important one.

	- Overlays. Overlays are optional files usually used to extract
	configuration for some specific case or feature from the general application
	configuration. The main difference between them and the application
	`prj.conf` file is that they are not included automatically, so you can
	decide whether to build sample with or without them. Overlay files can be
	added to build by typing the following command in the example directory,
	with _build-target_ replaced with the build target name (e.g.
	_nrf52840dk_nrf52840_) and _overlay_file_name_ replaced with the overlay
	configuration file name (e.g. _overlay-usb_support.conf_):

	$ west build -b build-target -- -DOVERLAY_CONFIG=overlay_file_name

	Read the
	[Kconfig](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/kconfig/index.html#kconfig)
	guide in the nRF Connect SDK's Zephyr documentation if you are interested in
	getting more advanced and detailed information about the configuration
	structure.

	<hr>

	## Configuring Matter in nRF Connect platform

	### Mandatory configuration

	To use the Matter protocol, you need to set the `CONFIG_CHIP` Kconfig option.
	Setting this option enables the Matter protocol stack and other associated
	Kconfig options, including `CONFIG_CHIP_ENABLE_DNSSD_SRP` that is required for
	the Matter device to be discoverable using DNS-SD.

	After that, make sure to set the `CONFIG_CHIP_PROJECT_CONFIG` Kconfig option and
	define the path to the configuration file that specifies Vendor ID, Product ID,
	and other project-specific Matter settings.

	<hr>

	### Optional configuration

	After enabling the Matter protocol and defining the path to the Matter
	configuration file, you can enable additional options in Kconfig.

	Sleepy End Device support

	You can enable the support for Thread Sleepy End Device in Matter by setting the
	following Kconfig options:

	- `CONFIG_OPENTHREAD_MTD`
	- `CONFIG_CHIP_ENABLE_SLEEPY_END_DEVICE_SUPPORT`

	The following Kconfig options can be used to tune Thread Sleepy End Device wake
	intervals:

	- `CONFIG_CHIP_SED_IDLE_INTERVAL`
	- `CONFIG_CHIP_SED_ACTIVE_INTERVAL`

	Commissioning with NFC support

	You can configure the Matter protocol to use an NFC tag for commissioning,
	instead of using a QR code, which is the default configuration.

	To enable NFC for commissioning and share the onboarding payload in an NFC tag,
	set the `CONFIG_CHIP_NFC_COMMISSIONING` option.

	Factory reset behavior

	By default, the factory reset procedure implemented in the Matter stack removes
	Matter-related settings only. If your application does not depend on any
	device-lifelong data stored in the non-volatile storage, set the
	`CONFIG_CHIP_FACTORY_RESET_ERASE_NVS` option to fully erase the NVS partition at
	the factory reset. This approach is more robust and regains the original NVS
	performance in case it has been polluted with unwanted entries.

	Logging

	You can enable logging for both the stack and Zephyr’s
	[Logging](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/reference/logging/index.html#logging-api)
	API by setting the `CONFIG_LOG` option.

	Zephyr allows you to configure log levels of different software modules
	independently. To change the log level configuration for the Matter module, set
	one of the available options:

	- `CONFIG_MATTER_LOG_LEVEL_ERR`
	- `CONFIG_MATTER_LOG_LEVEL_INFO`
	- `CONFIG_MATTER_LOG_LEVEL_DBG`

	Shell

	You can enable the Matter shell library using the `CONFIG_CHIP_LIB_SHELL`
	Kconfig option. This option lets you use the Matter specific shell commands. See
	[Using CLI in nRF Connect examples](nrfconnect_examples_cli.md) for the list of
	available Matter shell commands.

	Matter device identification

	Matter has many mandatory and optional ways to identify a specific device. These
	can be used for various purposes, such as dividing devices into groups (by
	function, by vendor or by location), device commissioning or vendor-specific
	cases before the device was commissioned (for example, identifying factory
	software version or related features).

	Only some part of these features can be configured using Kconfig options and
	only those were listed below:

	- `CONFIG_CHIP_DEVICE_TYPE` - type of device that uses the Matter Device Type
	Identifier, for example Door Lock (0x000A) or Dimmable Light Bulb (0x0101).
	- `CONFIG_CHIP_COMMISSIONABLE_DEVICE_TYPE` - enables including optional device
	type subtype in the commissionable node discovery record, which allows
	filtering of the discovery results to find the nodes that match the device
	type.
	- `CONFIG_CHIP_ROTATING_DEVICE_ID` - enables rotating device identifier, an
	optional feature that provides an additional unique identifier for each
	device. This identifier is similar to the serial number, but it additionally
	changes at predefined times to protect against long-term tracking of the
	device.