Bluetooth Low Energy Remote Procedure Call

The nRF Connect SDK supports Bluetooth® Low Energy (LE) stack serialization. The full Bluetooth LE stack can run on another device or CPU, such as the nRF5340 DK network core using Remote procedure call library (nRF RPC).

Note

The nRF Connect SDK currently supports serialization of the Generic Access Profile (GAP) and the Connection Management only. Due to the limited support, a special CONFIG_SUPPORT_BT_RPC option was added and it allows enabling the CONFIG_BT_RPC option. Samples using other Bluetooth LE features, such as GATT, are currently not supported and they have the CONFIG_SUPPORT_BT_RPC option disabled. If you want to use the CONFIG_BT_RPC option in your application, you must create a Kconfig file with following content:

config SUPPORT_BT_RPC
  bool
  default y

source "Kconfig.zephyr"

Network core

The Bluetooth: Host for nRF RPC Bluetooth Low Energy sample is designed specifically to enable the Bluetooth LE stack functionality on a remote MCU (for example, the nRF5340 network core) using the Remote procedure call library (nRF RPC). You can program this sample to the network core to run standard Bluetooth Low Energy samples on nRF5340. You can use either the SoftDevice Controller or the Zephyr Bluetooth LE Controller for this sample.

Application core

To use the Bluetooth LE stack through nRF RPC, an additional configuration is needed. When building samples for the application core, enable the CONFIG_BT_RPC to run the Bluetooth LE stack on the network core. This option builds Bluetooth: Host for nRF RPC Bluetooth Low Energy automatically as a child image. For more details, see: Building and programming a sample.

Open a command prompt in the build folder of the application sample and enter the following command to build the application for the application core, with Bluetooth: Host for nRF RPC Bluetooth Low Energy as child image:

west build -b nrf5340dk_nrf5340_cpuapp -- -DCONFIG_BT_RPC=y

Requirements

Some configuration options related to Bluetooth LE must be the same on the host (network core) and client (application core). Set the following options in the same way for the Bluetooth: Host for nRF RPC Bluetooth Low Energy and application core sample:

• CONFIG_BT_CENTRAL

• CONFIG_BT_PERIPHERAL

• CONFIG_BT_WHITELIST

• CONFIG_BT_USER_PHY_UPDATE

• CONFIG_BT_USER_DATA_LEN_UPDATE

• CONFIG_BT_PRIVACY

• CONFIG_BT_SCAN_WITH_IDENTITY

• CONFIG_BT_REMOTE_VERSION

• CONFIG_BT_SMP

• CONFIG_BT_CONN

• CONFIG_BT_REMOTE_INFO

• CONFIG_BT_FIXED_PASSKEY

• CONFIG_BT_SMP_APP_PAIRING_ACCEPT

• CONFIG_BT_EXT_ADV

• CONFIG_BT_OBSERVER

• CONFIG_BT_ECC

• CONFIG_BT_DEVICE_NAME_DYNAMIC

• CONFIG_BT_SMP_SC_PAIR_ONLY

• CONFIG_BT_PER_ADV

• CONFIG_BT_PER_ADV_SYNC

• CONFIG_BT_MAX_CONN

• CONFIG_BT_ID_MAX

• CONFIG_BT_EXT_ADV_MAX_ADV_SET

• CONFIG_BT_DEVICE_NAME_MAX

• CONFIG_BT_DEVICE_NAME_MAX

• CONFIG_BT_PER_ADV_SYNC_MAX

• CONFIG_BT_DEVICE_NAME

• CONFIG_CBKPROXY_OUT_SLOTS on one core must be equal to CONFIG_CBKPROXY_IN_SLOTS on the other.

To keep all the above configuration options in sync, create an overlay file that is shared between the application and network core. Then, you can invoke build command like this:

west build -b board -- -DCONFIG_OVERLAY=my_overlay_file.conf