203 lines
6.3 KiB
ReStructuredText
203 lines
6.3 KiB
ReStructuredText
.. zephyr:code-sample:: bluetooth_hci_uart
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:name: HCI UART
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:relevant-api: hci_raw bluetooth uart_interface
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Expose a Bluetooth controller to another device or CPU over UART.
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Overview
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*********
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Expose Bluetooth controller support over UART to another device/CPU
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using the H:4 HCI transport protocol (requires HW flow control from the UART).
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Requirements
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************
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* A board with Bluetooth LE support
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Default UART settings
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*********************
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By default the controller builds use the following settings:
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* Baudrate: 1Mbit/s
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* 8 bits, no parity, 1 stop bit
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* Hardware Flow Control (RTS/CTS) enabled
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Building and Running
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********************
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This sample can be found under :zephyr_file:`samples/bluetooth/hci_uart` in the
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Zephyr tree, and it is built as a standard Zephyr application.
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Using the controller with emulators and BlueZ
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*********************************************
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The instructions below show how to use a Nordic nRF5x device as a Zephyr BLE
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controller and expose it to Linux's BlueZ. This can be very useful for testing
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the Zephyr Link Layer with the BlueZ Host. The Zephyr Bluetooth LE controller can also
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provide a modern Bluetooth LE 5.0 controller to a Linux-based machine for native
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BLE support or QEMU-based development.
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First, make sure you have a recent BlueZ version installed by following the
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instructions in the :ref:`bluetooth_bluez` section.
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Now build and flash the sample for the Nordic nRF5x board of your choice.
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All of the Nordic Development Kits come with a Segger IC that provides a
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debugger interface and a CDC ACM serial port bridge. More information can be
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found in :ref:`nordic_segger`.
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For example, to build for the nRF52832 Development Kit:
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.. zephyr-app-commands::
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:zephyr-app: samples/bluetooth/hci_uart
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:board: nrf52dk/nrf52832
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:goals: build flash
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.. _bluetooth-hci-uart-qemu-posix:
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Using the controller with QEMU or native_sim
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============================================
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In order to use the HCI UART controller with QEMU or :ref:`native_sim <native_sim>` you will need
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to attach it to the Linux Host first. To do so simply build the sample and
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connect the UART to the Linux machine, and then attach it with this command:
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.. code-block:: console
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sudo btattach -B /dev/ttyACM0 -S 1000000 -R
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.. note::
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Depending on the serial port you are using you will need to modify the
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``/dev/ttyACM0`` string to point to the serial device your controller is
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connected to.
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.. note::
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If using the BBC micro:bit you will need to modify the baudrate argument
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from ``1000000`` to ``115200``.
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.. note::
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The ``-R`` flag passed to ``btattach`` instructs the kernel to avoid
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interacting with the controller and instead just be aware of it in order
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to proxy it to QEMU later.
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If you are running :file:`btmon` you should see a brief log showing how the
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Linux kernel identifies the attached controller.
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Once the controller is attached follow the instructions in the
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:ref:`bluetooth_qemu_native` section to use QEMU with it.
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.. _bluetooth-hci-uart-bluez:
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Using the controller with BlueZ
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===============================
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In order to use the HCI UART controller with BlueZ you will need to attach it
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to the Linux Host first. To do so simply build the sample and connect the
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UART to the Linux machine, and then attach it with this command:
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.. code-block:: console
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sudo btattach -B /dev/ttyACM0 -S 1000000
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.. note::
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Depending on the serial port you are using you will need to modify the
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``/dev/ttyACM0`` string to point to the serial device your controller is
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connected to.
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.. note::
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If using the BBC micro:bit you will need to modify the baudrate argument
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from ``1000000`` to ``115200``.
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If you are running :file:`btmon` you should see a comprehensive log showing how
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BlueZ loads and initializes the attached controller.
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Once the controller is attached follow the instructions in the
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:ref:`bluetooth_ctlr_bluez` section to use BlueZ with it.
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Debugging the controller
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========================
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The sample can be debugged using RTT since the UART is otherwise used by this
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application. To enable debug over RTT the debug configuration file can be used.
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.. code-block:: console
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west build samples/bluetooth/hci_uart -- -DEXTRA_CONF_FILE='debug.conf'
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Then attach RTT as described here: :ref:`Using Segger J-Link <Using Segger J-Link>`
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Support for the Direction Finding
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=================================
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The sample can be built with the support for the Bluetooth LE Direction Finding.
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To enable this feature build this sample for specific board variants that provide
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required hardware configuration for the Radio.
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.. code-block:: console
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west build samples/bluetooth/hci_uart -b nrf52833dk/nrf52833@df -- -DCONFIG_BT_CTLR_DF=y
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You can use following targets:
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* ``nrf5340dk/nrf5340/cpunet@df``
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* ``nrf52833dk/nrf52833@df``
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Check the :zephyr:code-sample:`ble_direction_finding_connectionless_rx` and the
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:zephyr:code-sample:`ble_direction_finding_connectionless_tx` for more details.
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Using a USB CDC ACM UART
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========================
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The sample can be configured to use a USB UART instead. See :zephyr_file:`samples/bluetooth/hci_uart/boards/nrf52840dongle_nrf52840.conf`.
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Using the controller with the Zephyr host
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=========================================
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This describes how to hook up a board running this sample to a board running
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an application that uses the Zephyr host.
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On the controller side, the ``zephyr,bt-c2h-uart`` DTS property (in the ``chosen``
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block) is used to select which uart device to use. For example if we want to
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keep the console logs, we can keep console on uart0 and the HCI on uart1 like
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so:
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.. code-block:: dts
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/ {
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chosen {
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zephyr,console = &uart0;
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zephyr,shell-uart = &uart0;
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zephyr,bt-c2h-uart = &uart1;
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};
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};
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On the host application, some config options need to be used to select the H4
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driver instead of the built-in controller:
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.. code-block:: cfg
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CONFIG_BT_HCI=y
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CONFIG_BT_CTLR=n
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Similarly, the ``zephyr,bt-hci`` DTS property selects which HCI instance to use.
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The UART needs to have as its child node a HCI UART node:
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.. code-block:: dts
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/ {
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chosen {
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zephyr,console = &uart0;
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zephyr,shell-uart = &uart0;
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zephyr,bt-hci = &bt_hci_uart;
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};
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};
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&uart1 {
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status = "okay";
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bt_hci_uart: bt_hci_uart {
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compatible = "zephyr,bt-hci-uart";
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status = "okay";
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};
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};
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