1.. zephyr:code-sample:: bluetooth_hci_spi
2   :name: HCI SPI
3   :relevant-api: hci_raw bluetooth spi_interface
4
5   Expose a Bluetooth controller to another device or CPU over SPI.
6
7Overview
8********
9
10Expose Bluetooth Controller support over SPI to another device/CPU using
11the Zephyr SPI HCI transport protocol (similar to BlueNRG).
12
13Requirements
14************
15
16A board with SPI slave, GPIO and Bluetooth Low Energy support.
17
18Building and Running
19********************
20
21You then need to ensure that your :ref:`devicetree <dt-guide>` defines a node
22for the HCI SPI slave device with compatible
23:dtcompatible:`zephyr,bt-hci-spi-slave`. This node sets an interrupt line to
24the host and associates the application with a SPI bus to use.
25
26See :zephyr_file:`boards/nrf51dk_nrf51822.overlay
27<samples/bluetooth/hci_spi/boards/nrf51dk_nrf51822.overlay>` in this sample
28directory for an example overlay for the :ref:`nrf51dk_nrf51822` board.
29
30You can then build this application and flash it onto your board in
31the usual way; see :ref:`boards` for board-specific building and
32flashing information.
33
34You will also need a separate chip acting as BT HCI SPI master. This
35application is compatible with the HCI SPI master driver provided by
36Zephyr's Bluetooth HCI driver core; see the help associated with the
37:kconfig:option:`CONFIG_BT_SPI` configuration option for more information.
38
39Refer to :zephyr:code-sample-category:`bluetooth` for general Bluetooth information, and
40to :ref:`96b_carbon_nrf51_bluetooth` for instructions specific to the
4196Boards Carbon board.
42