.. zephyr:code-sample:: bluetooth_direction_finding_central
:name: Direction Finding Central
:relevant-api: bluetooth
Connect to a Bluetooth LE Direction Finding peripheral and request Constant Tone Extension.
Overview
********
A simple application demonstrating the Bluetooth LE Direction Finding CTE reception in
connected mode by requesting transmission of a packet containing Constant
Tone Extension by connected peer device.
Requirements
************
* Nordic nRF SoC based board with Direction Finding support (example boards:
:ref:`nrf52833dk_nrf52833`, :ref:`nrf52833dk_nrf52820`, :ref:`nrf5340dk_nrf5340`)
* Antenna matrix for AoA (optional)
Check your SoC's product specification for Direction Finding support if you are
unsure.
Building and Running
********************
By default the application supports Angle of Arrival and Angle of Departure mode.
To use Angle of Departure mode only, build this application as follows,
changing ``nrf52833dk/nrf52833`` as needed for your board:
.. zephyr-app-commands::
:zephyr-app: samples/bluetooth/direction_finding_central
:host-os: unix
:board: nrf52833dk/nrf52833
:gen-args: -DEXTRA_CONF_FILE=overlay-aod.conf
:goals: build flash
:compact:
To run the application on nRF5340DK, a Bluetooth controller application must
also run on the network core. The :zephyr:code-sample:`bluetooth_hci_ipc` sample
application may be used. To build this sample with direction finding support
enabled:
* Copy
:zephyr_file:`samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.overlay`
to a new file,
:file:`samples/bluetooth/hci_ipc/boards/nrf5340dk_nrf5340_cpunet.overlay`.
* Make sure the same GPIO pins are assigned to Direction Finding Extension in file
:zephyr_file:`samples/bluetooth/direction_finding_central/boards/nrf5340dk_nrf5340_cpuapp.overlay`.
as those in the created file :file:`samples/bluetooth/hci_ipc/boards/nrf5340dk_nrf5340_cpunet.overlay`.
* Copy
:zephyr_file:`samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.conf`
to a new file,
:file:`samples/bluetooth/hci_ipc/boards/nrf5340dk_nrf5340_cpunet.conf`.
Antenna matrix configuration
****************************
To use this sample with Angle of Arrival enabled on Nordic SoCs, additional
configuration must be provided via :ref:`devicetree <dt-guide>` to enable
control of the antenna array.
An example devicetree overlay is in
:zephyr_file:`samples/bluetooth/direction_finding_central/boards/nrf52833dk_nrf52833.overlay`.
You can customize this overlay when building for the same board, or create your
own board-specific overlay in the same directory for a different board. See
:dtcompatible:`nordic,nrf-radio` for documentation on the properties used in
this overlay. See :ref:`set-devicetree-overlays` for information on setting up
and using overlays.
Note that antenna matrix configuration for the nRF5340 SoC is part of the
network core application. When :zephyr:code-sample:`bluetooth_hci_ipc` is used as the
network core application, the antenna matrix configuration should be stored in
the file
:file:`samples/bluetooth/hci_ipc/boards/nrf5340dk_nrf5340_cpunet.overlay`
instead.
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