Bluetooth: Broadcast Audio Profile Broadcast Assistant

This document describes how to run the BAP Broadcast Assistant functionality. Note that in the examples below, some lines of debug have been removed to make this shorter and provide a better overview.

The Broadcast Assistant is responsible for offloading scan for a resource restricted device, such that scanning does not drain the battery. The Broadcast Assistant shall support scanning for periodic advertisements and may optionally support the periodic advertisements synchronization transfer (PAST) protocol.

The Broadcast Assistant will typically be phones or laptops. The Broadcast Assistant scans for periodic advertisements and transfer information to the server.

It is necessary to have BT_DEBUG_BAP_BROADCAST_ASSISTANT enabled for using the Broadcast Assistant interactively.

When the Bluetooth stack has been initialized (bt init), and a device has been connected, the Broadcast Assistant can discover BASS on the connected device calling bap_broadcast_assistant discover, which will start a discovery for the BASS UUIDs and store the handles, and subscribe to all notifications.

bap_broadcast_assistant - Bluetooth BAP Broadcast Assistant shell commands
   discover        :Discover BASS on the server
   scan_start      :Start scanning for broadcasters
   scan_stop       :Stop scanning for BISs
   add_src         :Add a source <address: XX:XX:XX:XX:XX:XX> <type:
                    public/random> <adv_sid> <sync_pa> <broadcast_id>
                    [<pa_interval>] [<sync_bis>] [<metadata>]
   mod_src         :Set sync <src_id> <sync_pa> [<pa_interval>] [<sync_bis>]
   broadcast_code  :Send a space separated broadcast code of up to 16 bytes
                    <src_id> [broadcast code]
   rem_src         :Remove a source <src_id>
   read_state      :Remove a source <index>

Example usage


uart:~$ bt init
uart:~$ bt connect xx:xx:xx:xx:xx:xx public

When connected

Start scanning for periodic advertisements for a server:


The Broadcast Assistant will not actually start scanning for periodic advertisements, as that feature is still, at the time of writing, not implemented.

uart:~$ bap_broadcast_assistant discover
<dbg> bt_bap_broadcast_assistant.char_discover_func: Found 1 BASS receive states
<dbg> bt_bap_broadcast_assistant.read_recv_state_cb: src_id 0, PA 0, BIS 0, encrypt 0, addr 00:00:00:00:00:00 (public), sid 0, metadata_len 0
uart:~$ bap_broadcast_assistant scan_start
<dbg> bt_bap_broadcast_assistant.write_func: err: 0x00, handle 0x001e

Adding a source to the receive state:

uart:~$ bap_broadcast_assistant add_src 11:22:33:44:55:66 public 5 1 1
BASS recv state: src_id 0, addr 11:22:33:44:55:66 (public), sid 5, sync_state 1, encrypt_state 000000000000000000000000000000000
     [0]: BIS sync 0, metadata_len 0