nRF5340 audio CONNECT_IND Question

[gfgf2400a]

Hi I am using nRF5340 audio DK (pca10121) and I was able to evaluate LC3 LE audio example code between nRF5340 audio DK gateway and nRF5340 audio DK headset.

Since Samsung Galaxy Buds2 Pro with LC3 support firmware released on 1/16/2023. I was able to use nRF Connect Desktop to pair with Samsung Galaxy Buds2 Pro. From Nordic BLE sniffer, I saw:

1. Buds2 Pro broadcastED ADV_IND
2. nRF Connect Desktop sent SCAN_REQ
3. Buds2 Pro sent SCAN_RSP
4. nRF Connect Desktop sent CONNECT_IND

This is a good case. I then compared to nRF5340 audio DK gateway firmware pairing to Buds2 Pro. The first 2 steps ADV_IND, SCAN_REQ and SCAN_RSP were identical which mean Buds2 Pro response with the correct SCAN_RSP. However, nRF5340 audio DK gateway firmware did NOT send CONNECT_IND. i browsed through the nRF5340 audio DK gateway firmware example code but I could not find where CONNECT_IND initiates. Please point me to the code area for this CONNECT_IND handling.

Second, what could be the reason. Thanks in advance,

Dennis 

[Kenneth]

Hello,

Searching through the project I can find it's handled in:
C:\ncs\v2.2.0\nrf\applications\nrf5340_audio\src\bluetooth\le_audio_cis_gateway.c

Look in on_device_found() and in specific:

        /* Note: May lead to connection creation */
        ad_parse(p_ad, addr);

I guess the actual connection establish is done in device_found().

Kenneth

[gfgf2400a]

I saw on_device_found() function but I don't see where CONNECT_IND handling?

[gfgf2400a]

I think device_found() calls bt_conn_le_create() and this is where CONNECT_IND sends out

[Kenneth]

The connect_ind packet itself is abstracted away (very tight timing that does not make any sense the application look at), instead as a gateway you can choose which devices you want to connect to by calling bt_conn_le_create(). So in your case you can try to modify 
https://github.com/nrfconnect/sdk-nrf/blob/main/applications/nrf5340_audio/src/bluetooth/le_audio_cis_gateway.c#L675 
such that bt_conn_le_create() is called for the device you want to connect to (this will trigger the connect_ind you are looking for).

Kenneth

[gfgf2400a]

thank you so much, I am making progress:

GW [00:00:02.526,702] <inf> bt_scan: bt_le_scan_start
GW [00:00:02.528,686] <inf> cis_gateway: Scanning successfully started
uart:~$ GW [00:00:02.714,691] <inf> cis_gateway: on_device_found: ADV_IND 94:2f:69:db:79:c0
GW [00:00:02.714,691] <inf> cis_gateway: ad_parse
GW [00:00:02.714,691] <inf> cis_gateway: device_found: ADV_IND 94:2f:69:db:79:c0
GW [00:00:02.714,691] <dbg> cis_gateway: device_found: Device found
GW [00:00:02.715,270] <inf> bt_conn: disconnected -> connecting
GW [00:00:02.802,154] <inf> bt_conn: connecting -> connected
GW [00:00:02.802,917] <inf> cis_gateway: Connected: C0:79:DB:69:2F:94 (random)
GW [00:00:03.103,759] <err> cis_gateway: Security failed: level 1 err 2
GW [00:00:03.103,973] <inf> bt_conn: connected -> disconnecting
GW [00:00:03.204,833] <inf> bt_conn: disconnecting -> disconnect-complete

Please let me know what caused " cis_gateway: Security failed: level 1 err 2". I am suspecting LE secure connection or bond option that I was not set up correctly. Please advise

[Kenneth]

gfgf2400a said:

Please let me know what caused " cis_gateway: Security failed: level 1 err 2".

Err 2 is BT_SECURITY_ERR_PIN_OR_KEY_MISSING.

Are the headsets in pairing mode?

Kenneth