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 

[gfgf2400a]

Here are the actual packets from Nordic sniffer:

• Good case with nRF Connect desktop: Galaxy-3ConnectIndTonRFConnect.txt
• Missing CONNECT_IND: Galaxy-3ScanRspTonRF5340.txt
  Fullscreen Galaxy-3ConnectIndTonRFConnect.txt Download

  Frame 5471: 55 bytes on wire (440 bits), 55 bytes captured (440 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x1d60 (PDU Type: ADV_IND, ChSel: #2, TxAdd: Random)
          .... 0000 = PDU Type: 0x0 ADV_IND
          ...0 .... = Reserved: 0
          ..1. .... = Channel Selection Algorithm: #2
          .1.. .... = Tx Address: Random
          0... .... = Reserved: 0
          Length: 29
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      Advertising Data
          Manufacturer Specific
              Length: 18
              Type: Manufacturer Specific (0xff)
              Company ID: Microsoft (0x0006)
              Data: 03028004442442756473322050726f
          Appearance: Unknown
              Length: 3
              Type: Appearance (0x19)
              Appearance: Unknown (0x0941)
      CRC: 0x699e5e
  
  Frame 5472: 38 bytes on wire (304 bits), 38 bytes captured (304 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x0cc3 (PDU Type: SCAN_REQ, TxAdd: Random, RxAdd: Random)
          .... 0011 = PDU Type: 0x3 SCAN_REQ
          ...0 .... = Reserved: 0
          ..0. .... = Reserved: 0
          .1.. .... = Tx Address: Random
          1... .... = Rx Address: Random
          Length: 12
      Scanning Address: c7:cb:77:0f:73:be (c7:cb:77:0f:73:be)
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      CRC: 0xefa68c
  
  Frame 5473: 32 bytes on wire (256 bits), 32 bytes captured (256 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x0644 (PDU Type: SCAN_RSP, TxAdd: Random)
          .... 0100 = PDU Type: 0x4 SCAN_RSP
          ...0 .... = Reserved: 0
          ..0. .... = Reserved: 0
          .1.. .... = Tx Address: Random
          0... .... = Reserved: 0
          Length: 6
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      Scan Response Data: <MISSING>
      CRC: 0x1521d7
  
  Frame 5644: 60 bytes on wire (480 bits), 60 bytes captured (480 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x22e5 (PDU Type: CONNECT_IND, ChSel: #2, TxAdd: Random, RxAdd: Random)
          .... 0101 = PDU Type: 0x5 CONNECT_IND
          ...0 .... = Reserved: 0
          ..1. .... = Channel Selection Algorithm: #2
          .1.. .... = Tx Address: Random
          1... .... = Rx Address: Random
          Length: 34
      Initiator Address: c7:cb:77:0f:73:be (c7:cb:77:0f:73:be)
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      Link Layer Data
      CRC: 0xd9b871
  
  
  

  Fullscreen Galaxy-3ScanRspTonRF5340.txt Download

  Frame 18083: 55 bytes on wire (440 bits), 55 bytes captured (440 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x1d60 (PDU Type: ADV_IND, ChSel: #2, TxAdd: Random)
          .... 0000 = PDU Type: 0x0 ADV_IND
          ...0 .... = Reserved: 0
          ..1. .... = Channel Selection Algorithm: #2
          .1.. .... = Tx Address: Random
          0... .... = Reserved: 0
          Length: 29
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      Advertising Data
          Manufacturer Specific
              Length: 18
              Type: Manufacturer Specific (0xff)
              Company ID: Microsoft (0x0006)
              Data: 03028004442442756473322050726f
          Appearance: Unknown
              Length: 3
              Type: Appearance (0x19)
              Appearance: Unknown (0x0941)
      CRC: 0x699e5e
  
  Frame 18084: 38 bytes on wire (304 bits), 38 bytes captured (304 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x0cc3 (PDU Type: SCAN_REQ, TxAdd: Random, RxAdd: Random)
          .... 0011 = PDU Type: 0x3 SCAN_REQ
          ...0 .... = Reserved: 0
          ..0. .... = Reserved: 0
          .1.. .... = Tx Address: Random
          1... .... = Rx Address: Random
          Length: 12
      Scanning Address: 58:73:90:b9:b1:05 (58:73:90:b9:b1:05)
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      CRC: 0x6913c2
  
  Frame 18085: 32 bytes on wire (256 bits), 32 bytes captured (256 bits) on interface COM17-4.0, id 0
  nRF Sniffer for Bluetooth LE
  Bluetooth Low Energy Link Layer
      Access Address: 0x8e89bed6
      Packet Header: 0x0644 (PDU Type: SCAN_RSP, TxAdd: Random)
          .... 0100 = PDU Type: 0x4 SCAN_RSP
          ...0 .... = Reserved: 0
          ..0. .... = Reserved: 0
          .1.. .... = Tx Address: Random
          0... .... = Reserved: 0
          Length: 6
      Advertising Address: c0:79:db:69:2f:94 (c0:79:db:69:2f:94)
      Scan Response Data: <MISSING>
      CRC: 0x1521d7