LE Audio controller for nRF5340

The LE Audio controller for nRF5340 is a link layer controller for the nRF5340 network core and is meant to be used with LE Audio applications.

This controller is compatible with the HCI RPMsg driver provided by the nRF Connect SDK Bluetooth® HCI Drivers core. When the communication between the application and the network core on a device is handled by the HCI RPMsg driver, this link layer controller can be used to handle time critical low level communication and the radio.

Note

The LE Audio controller for nRF5340 is under development and is provided in the experimental state. Make sure to always use the latest version of the controller.

LE Audio controller for nRF5340 QDID

The LE Audio controller for nRF5340 associated with this version of the nRF Connect SDK comes with the QDID #181316.

Configuration

The controller can be enabled with the CONFIG_BT_LL_ACS_NRF53 set to y.

The number of Connected Isochronous Streams (CIS) you can use in a Connected Isochronous Group (CIG) and the number of Broadcast Isochronous Streams (BIS) you can use in a Broadcast Isochronous Group (BIG) are dependent on which configurations you use. The most relevant configurations are bitrate and number of retransmissions. See the Capabilities for the LE Audio Controller Subsystem for nRF5340 document for matrix tables listing the supported CIS in a CIG and the supported BIS in a BIG. These matrix tables are based on the Basic Audio Profile (BAP) tables.

The controller has the following methods of configuration:

  • Standard Host-Controller Interface (HCI) commands

  • Vendor-Specific commands (VSC)

These are listed in ble_hci_vsc.h. See the API documentation for more information.

Usage

This controller is provided as a HEX file and includes the LE Audio Controller Subsystem for nRF53. Check the license file in the /bin directory for usage conditions.

The HEX file is to be used with the nRF Connect SDK version it is delivered with. Other combinations are not tested and their behavior is undefined.

When using the file, the controller is programmed to the network core of nRF5340. Configurations and calls are handled through standard HCI and VSC.

Samples using the library

The nRF5340 Audio application uses the controller.

Files

The network core for both gateway and headsets of the nRF5340 Audio is programmed with the precompiled Bluetooth Low Energy Controller binary file ble5-ctr-rpmsg_<XYZ>.hex, where <XYZ> corresponds to the controller version, for example ble5-ctr-rpmsg_3216.hex. This file includes the LE Audio Controller Subsystem for nRF53. If DFU is enabled, the subsystem’s binary file will be generated in the build/zephyr/ directory and will be called net_core_app_signed.hex.

There are two other files in the /bin directory:

  • ble5-ctr-rpmsg_shifted_<XYZ>.hex which has been shifted to make space for MCUboot.

  • ble5-ctr-rpmsg_shifted_min_<XYZ>.hex which is the same as above, but made for minimum MCUboot.

Also for these files, <XYZ> corresponds to the controller version.

Limitations

The controller is marked as experimental.

This controller and the LE Audio Controller Subsystem for nRF5340 it includes has been tested and works in configurations used by the nRF5340 Audio application (for example, 2 concurrent CIS, or BIS). No other configurations than the ones used in the referenced application have been tested or documented for this library.

When you build the nRF5340 Audio application with the nRF21540 FEM support, the LE Audio controller for nRF5340 does not support the +20 dBm setting. This is because of a power class restriction in the controller’s QDID.

Dependencies

As the controller is provided precompiled in a binary format, there are no software dependencies. In terms of hardware, this controller is only compatible with the nRF5340.

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