Problem encoding and advertising the BT_UUID_NUS_VAL

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

Simonr — Wed, 07 Feb 2024 13:59:15 GMT

I've been discussing this issue with a colleague that is more into the LE audio stack than me, and we would like to see if you can recreate this issue using the SoftDevice controller (SDC)as well, just to confirm this doesn't have something to do with the packetcraft controller specifically, so here are some steps you can try:

Checkout the latest NCS main, since the SDC with ISO is merged after NCS 2.5.0, and also some modification are needed for applications to run with the SDC. This PR brings ISO onto the SDC, and this one updates buildprog.py for switching between SDC and PCFT.
For using buildprog.py, add the command --ctlr="SDC" in the end. E.g., $ python buildprog.py -c both -b debug -d both -p --pristine--ctlr="SDC"
For using west, we need to add -DCONFIG_BT_LL_ACS_NRF53=n
E.g., $ west build -b nrf5340_audio_dk_nrf5340_cpuapp -d build_headset -p -- -DCONFIG_AUDIO_DEV=1 -DCONFIG_BT_LL_ACS_NRF53=n; west flash --build-dir=build_headset

If that doesn't change anything either, we will need to take a closer look at your project. If you could upload a version of your project where we can reproduce this on our end that would be very helpful.

I know that the LE audio application has been able to advertise custom UUIDs in the past, so we will get to the bottom of this, one way or the other.

Best regards,

Simon

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

saml — Wed, 07 Feb 2024 07:05:55 GMT

Hi. I am trying to develop for the audio application.

The crashing problem was also reported here when just using bt_le_adv_start() without bt_mgmt_adv_start() :

(1) Audio application - No valid advertising data stored - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

Simonr — Tue, 06 Feb 2024 12:58:59 GMT

Hi again Sam

I don't see how an application crashing when the receiver disconnects (already in a connection) would be because of the advertising data. What error exactly is causing this disconnect, do you have an error log to show?

Can you confirm you're trying to develop for the Audio application or not, since this bt_mgmt_adv_start() function is specifically made for ACL connections in the LE audio application. If not bt_mgmt_adv_start() won't be the correct call to use here. I will need to ask the devs about if it's possible to use bt_mgmt_adv_start() with 128 bit UUIDs as I haven't been able to find a way on my own unfortunately.

Best regards,

Simon

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

saml — Mon, 05 Feb 2024 13:10:24 GMT

Simonr Sorry for the delay. I'm just back at work now.

The problem with using bt_le_adv_start() is that the application sometimes crashes when the receiver disconnects from the central device reporting no valid advertising data.

It became clear that I needed to call bt_mgmt_adv_start() initially. When bt_mgmt_adv_start() is used, the advertising_process() function gets invoked eventually which uses extended_adv_create() and bt_le_ext_adv_start(). This must use a struct like the unicast_server_adv_data above for containing the advertising data data.

How have you set the advertising type and UUID type in your project?

How do I ? I'm not really sure. Here is how the BT_DATA_BYTES is used in the Peripheral UART sample, but when using bt_le_adv_start().

static const struct bt_data ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)),
	BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN),
};

static const struct bt_data sd[] = {
	BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
};

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

Simonr — Fri, 02 Feb 2024 07:44:02 GMT

What issues exactly did you have with bt_le_adv_start()?

It seems what you're trying to input in the .type field of your BT_DATA is not recorded or in the union initializer. This should be the type of advertising data field of your application that isn't set correctly it seems. How have you set the advertising type and UUID type in your project?

Best regards,

Simon

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

saml — Thu, 01 Feb 2024 10:56:41 GMT

Hi Simonr

When I try to create the advertising data as follows, for mgmt_adv_start() :

static uint8_t unicast_server_adv_data[] = {
	BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
	BT_AUDIO_UNICAST_ANNOUNCEMENT_TARGETED,
	BT_BYTES_LIST_LE16(AVAILABLE_SINK_CONTEXT),
	BT_BYTES_LIST_LE16(AVAILABLE_SOURCE_CONTEXT),
	0x00, /* Metadata length */
};

I get all sorts of issues :

warning: braces around scalar initializer
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: (near initialization for 'adv_data[0]')
In file included from C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/conn.h:23,
                 from C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/hci.h:16,
                 from C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/buf.h:24,
                 from C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/audio/audio.h:22,
                 from ../../../src/bluetooth/le_audio.h:10,
                 from ../../../src/bluetooth/bt_stream/broadcast/broadcast_sink.h:10,
                 from ../../../src/audio/streamctrl_broadcast_sink.c:13:
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:451:17: error: field name not in record or union initializer
  451 |                 .type = (_type), \
      |                 ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:451:17: note: (near initialization for 'adv_data[0]')
  451 |                 .type = (_type), \
      |                 ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:452:17: error: field name not in record or union initializer
  452 |                 .data_len = (_data_len), \
      |                 ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:452:17: note: (near initialization for 'adv_data[0]')
  452 |                 .data_len = (_data_len), \
      |                 ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:452:29: warning: excess elements in scalar initializer
  452 |                 .data_len = (_data_len), \
      |                             ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:452:29: note: (near initialization for 'adv_data[0]')
  452 |                 .data_len = (_data_len), \
      |                             ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:453:17: error: field name not in record or union initializer
  453 |                 .data = (const uint8_t *)(_data), \
      |                 ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:453:17: note: (near initialization for 'adv_data[0]')
  453 |                 .data = (const uint8_t *)(_data), \
      |                 ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:453:25: warning: excess elements in scalar initializer
  453 |                 .data = (const uint8_t *)(_data), \
      |                         ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:453:25: note: (near initialization for 'adv_data[0]')
  453 |                 .data = (const uint8_t *)(_data), \
      |                         ^
C:/ncs/v2.5.1/zephyr/include/zephyr/bluetooth/bluetooth.h:466:9: note: in expansion of macro 'BT_DATA'
  466 |         BT_DATA(_type, ((uint8_t []) { _bytes }), \
      |         ^~~~~~~
../../../src/audio/streamctrl_broadcast_sink.c:504:9: note: in expansion of macro 'BT_DATA_BYTES'
  504 |         BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_NUS_VAL),
      |         ^~~~~~~~~~~~~
ninja: build stopped: subcommand failed.

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

Simonr — Thu, 01 Feb 2024 07:01:23 GMT

What issues exactly did you have with bt_le_adv_start()? You need to make sure that the mgmt_adv_start() has room for 128 bits for the UUID. What errors are you running into exactly when trying to use bt_mgmt_adv_start() to advertise with the NUS UUID?

Best regards,

Simon

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

saml — Wed, 31 Jan 2024 14:40:09 GMT

Simonr Thanks for your reply.

The peripheral_uart sample uses bt_le_adv_start() to start the advertising. I can't use this in my case due to previous issues.

I must initialize advertising with bt_mgmt_adv_start() and eventually bt_le_ext_adv_start() gets called. I must use a structure similar to that of unicast_server_adv_data.

So is there no way to advertise the BT_UUID_NUS_VAL this way you mean? Only using the legacy bt_le_adv_start() .

I've taken the BLE fundamentals course already. Thanks.

RE: Problem encoding and advertising the BT_UUID_NUS_VAL

Simonr — Wed, 31 Jan 2024 13:51:47 GMT

I don't think you should use the unicast file (related to LE audio), to do standard BLE advertising. I'd strongly suggest checking out how advertising the Nordic UART service is done in the peripheral_uart sample, that does just this already. I'd also recommend the Nordic DevAcademy and the Bluetooth Low Energy fundamentals course that explains how to do BLE advertising in detail.

Best regards,

Simon