ref: 0.13.0
src/libs/mynewt-nimble/docs/ble_setup/ble_addr.rst
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Configure device address ------------------------ A BLE device needs an address to do just about anything. For information on the various types of Bluetooth addresses, see the `NimBLE Host Identity Reference :doc:`<../ble_hs/ble_hs_id/ble_hs_id>`. There are several methods for assigning an address to a NimBLE device. The available options are documented below: Method 1: Configure nRF hardware with a public address ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When Mynewt is running on a Nordic nRF platform, the NimBLE controller will attempt to read a public address out of the board's FICR or UICR registers. The controller uses the following logic while trying to read an address from hardware: 1. If the *DEVICEADDRTYPE* FICR register is written, read the address programmed in the *DEVICEADDR[0]* and *DEVICEADDR[1]* FICR registers. 2. Else if the upper 16 bits of the *CUSTOMER[1]* UICR register are 0, read the address programmed in the *CUSTOMER[0]* and *CUSTOMER[1]* UCI registers. 3. Else, no address available. Method 2: Hardcode a public address in the Mynewt target ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The NimBLE controller package exports a :doc:`syscfg <../../../os/modules/sysinitconfig/sysinitconfig>` setting called ``BLE_PUBLIC_DEV_ADDR``. This setting can be overridden at the application or target level to configure a public Bluetooth address. For example, a target can assign the public address *11:22:33:44:55:66* as follows: :: syscfg.vals: BLE_PUBLIC_DEV_ADDR: '(uint8_t[6]){0x66, 0x55, 0x44, 0x33, 0x22, 0x11}' This setting takes the form of a C expression. Specifically, the value is a designated initializer expressing a six-byte array. Also note that the bytes are reversed, as an array is inherently little-endian, while addresses are generally expressed in big-endian. Note: this method takes precedence over method 1. Whatever is written to the ``BLE_PUBLIC_DEV_ADDR`` setting is the address that gets used. Method 3: Configure a random address at runtime ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Random addresses get configured through the NimBLE host. The following two functions are used in random address configuration: - :doc:`ble_hs_id_gen_rnd <../ble_hs/ble_hs_id/functions/ble_hs_id_gen_rnd>`: Generates a new random address. - :doc:`ble_hs_id_set_rnd <../ble_hs/ble_hs_id/functions/ble_hs_id_set_rnd>`: Sets the device's random address. For an example of how this is done, see the :doc:`<../../../os/tutorials/ibeacon>`. *Note:* A NimBLE device can be configured with multiple addresses; at most one of each address type. |