No device found with bt_le_scan_start and observer

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Wed, 25 Jan 2023 13:31:16 GMT

Hi Hieu,

Thank you for your patience. Ok, I get it! I'll try to modify the application to use thread.

Best

Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Mon, 23 Jan 2023 16:57:41 GMT

Hi Marco,

I consult further with the same colleague again. The lessons that I linked previously are the best resources we would currently recommend.

Beyond the lessons, please read the documentation of the Zephyr OS. In particular, I think this page and its subpages are of immediate interest:

Kernel Services — Zephyr Project Documentation (nordicsemi.com)

We cannot really advise on how to setup the application in deeper details, as that depends a lot on teams'/personal preferences and the projects' natures.

Best regards,

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Fri, 20 Jan 2023 11:40:49 GMT

Hi Hieu,
thank you for your suggestion, I'll study the course. If you have any news, please share it with me!
In the meantime, I am facing another problem with USB, and I suppose that the issue is the same... but for this, I'll open a new ticket.
Best
Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Fri, 20 Jan 2023 10:25:32 GMT

Hi Marco,

Sorry I just now returned after a few days of sick leaves.

It is curious why there is no issue when you add advertising. I would assume the same problem will arise.
That being said, I too am not an expert with RTOS. I had to double check carefully with a colleague before sending my last reply.

I am sure that adding ksleep is a solution, having tried that myself. However, I am not certain that it is the best solution. My not-an-expert suggestion is indeed to use different threads to handle different duties, rather than doing everything in a while loop. Without knowing what you are doing in that while loop, that is the best suggestion I can make right now.

If you wish to learn more about the OS, Nordic does provide the nRF Connect SDK Fundamentals free online course. The Lesson 7 and 8 are made by the same colleague I mentioned above and should give you some idea. Though I suggest you still start from Lesson 1, and quickly skim and skip any topics you already know, rather than skipping the entire thing. There are some knowledge dependencies between the lessons.

Best regards,

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Fri, 20 Jan 2023 09:03:35 GMT

Hi Hieu

Do you have some ideas for me?

Best

Marco

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Tue, 17 Jan 2023 09:53:00 GMT

Hi Hieu,

Ok, I have a problem. At this time the CPU is always doing something in the application code... (in the clear project that I used for the previous test, the while loop is empty).

Which is the solution? Add in the main loop a ksleep or something else to switch threads (it is my first time with operating systems).

About your last question: yes, the code is the same and there was code into the main loop.

Best

Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Thu, 12 Jan 2023 21:04:01 GMT

Hi Marco,

Depends on what you do in your while loop. Does it ever yield CPU to other thread? If it is always doing something, then yes, that would be a problem.

Here is the description of the main thread from Zephyr OS documentation:

Main thread
This thread performs kernel initialization, then calls the application’s main() function (if one is defined).

By default, the main thread uses the highest configured preemptible thread priority (i.e. 0). If the kernel is not configured to support preemptible threads, the main thread uses the lowest configured cooperative thread priority (i.e. -1).

The main thread has the highest priority, and thus will not let any other thing runs unless it exits or actively yield.

I am not well versed in the topics of Zephyr OS thread, but my guess (which you please take with a grain of salt) is that your main thread chokes the printing, not the actual Bluetooth functionality that runs on a different core.

I am quite curious now how the setup with advertising works though. Does that setup also have the while loop?

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Wed, 11 Jan 2023 10:46:08 GMT

I found the difference:

In your code, after

Bluetooth_init();

the main exit but the application still alive. In My application, there is a while loop after the bluetooth initialization. Is that the problem?

Thank

Marco

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Wed, 11 Jan 2023 09:40:54 GMT

Hi Hieu,

it is very strange... there are no differences between the two project!

I am going crazy with that!

Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Tue, 10 Jan 2023 20:24:23 GMT

Hi Marco,

The fact that my project works on your end suggests that at least the problem is somewhere in the project setup, so it might be a good sign.

Could you run a diff/compare of the projects, see what the differences are? Remember to exclude the build folder.

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Tue, 10 Jan 2023 17:16:06 GMT

Hi Hieu,

sorry for the delay, but I was out-of-office for holiday.

Your code work without any problem. I tried a new fresh project... but not works! Same code, it is only a new project! It is unbelivable for me!

Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Mon, 02 Jan 2023 09:46:31 GMT

Hi Marco,

I tried on my nRF5340 DK and I cannot reproduce your issue where the device hangs after 5 seconds.

Could you please retry what you are doing on a fresh Hello World project? If possible, add each piece of code one at a time, with a quick test to see if it is behaving as you expected.

Attached below is my test project which I tested in NCS v2.2.0 with debug options. You can find that I am using pretty much the same code you provided here, and it works normaly. If you try it, when build, please remember to include "add_scan.conf" and "nrf5340.conf."

devzone.nordicsemi.com/.../hello_5F00_world_5F00_add_5F00_scan.zip

Hieu

RE: No device found with bt_le_scan_start and observer

Hieu — Thu, 29 Dec 2022 15:00:25 GMT

P.s: Are you enabling debug options in your build? If so, can you try the scan-only setup again without debug options? And if that works, can you try again with debug options but on NCS v2.0.2?

RE: No device found with bt_le_scan_start and observer

Hieu — Thu, 29 Dec 2022 14:58:55 GMT

Hi Marco,

This is too strange.

Unfortunately, I am accessing my DKs remotely and I didn't set a nRF5340 DK up. I will try to reproduce and debug this when I get back to office next week. I will follow up latest by the end of Wednesday Jan 4. Sorry if that seems a bit long. We are a bit understaffed because of the holidays.

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Thu, 29 Dec 2022 10:32:34 GMT

Hi Hieu,

by enabling the advertising concurrently without timeout the scanning works without problems as you can see in the image.

What can I do?

Thanks

Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Wed, 28 Dec 2022 21:35:33 GMT

Hi Marco,

Nice to meet you too!

Sorry for the late follow up. We are having a holiday staffing situation.

You could start advertising concurrently without timeout. The Scan & Advertise Sample shows you how to do it.

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Tue, 27 Dec 2022 07:55:26 GMT

Hi Hieu,

nice to meet you.

Yes, the scan stops working after mere five seconds.

For the test: can you suggest me the code to add this functionality?

Thanks

Marco

RE: No device found with bt_le_scan_start and observer

Hieu — Fri, 23 Dec 2022 22:58:45 GMT

Hi Marco,

Simon is out of office and I will substitute for him here.

From your description and your log, does the scan stop working after mere five seconds?

To ensure the net core is also working, could you also setup another BLE activities running in parallel with scanning and get the log? Perhaps the easiest is a beacon broadcasting without a timeout.

Best regards,

Hieu

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Thu, 22 Dec 2022 09:42:49 GMT

Hi Simon,

I added the row into the config file. I put the start scan a little bit earlier than before and now somethings came up as you can see in the image (the black side is the app core, the white side is the network core)... but after some seconds no more can be found... nothing.

Just to be sure of this behaviour I switched off some beacons, start the scan, and now switch on the beacons.. and it doesn't show these devices.

I am sure that the app core is not blocked in a while loop or in a fail, because it does other things!

Best regards

Marco

RE: No device found with bt_le_scan_start and observer

Simonr — Wed, 21 Dec 2022 13:23:17 GMT

Hi Marco

Can you try enabling CONFIG_BT_HCI=y as well in your config file. I'm not quite sure why you're not able to scan as expected with this implementation, might be because I'm missing insight, but your code builds fine in hello_world on our end. What Bluetooth controller are you using on the NET core? The Zephyr BLE controller or Nordic's SoftDevice controller?

Best regards,

Simon

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Wed, 21 Dec 2022 07:49:39 GMT

Hi Simon,

the observer example works fine.

My project started from the "hello world" example doesn't work. I put into the prj.conf all the configurations needed (like in the observer example), and other configurations for "mcuboot" and "sdcard", but the scanning doesn't work. You can see the configuration in the first post.

I don't know what I do in a different way from the observer example!

Thanks

Best regards

Marco

RE: No device found with bt_le_scan_start and observer

Simonr — Wed, 21 Dec 2022 07:31:35 GMT

I'm sorry, that's a misunderstanding on my end. From your last reply you say that the project work correctly? I thought the issue was that when building the project into an external directory was what caused the issue? What exactly do you do different to run into this scanning issue?

Best regards,

SImon

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Tue, 20 Dec 2022 08:24:19 GMT

Dear Simonr,

I mean that if I take the observer example and create the project in the same way of mine (into an external directory) it works and the project has both app part and net part (I suppose as child image).

Best

Marco

RE: No device found with bt_le_scan_start and observer

warcomeb-am — Tue, 20 Dec 2022 08:07:30 GMT

Sorry Simon,

but I don't understand... My project is not out-of-tree.

I created the project by using the VSC and NCS installed by nRF Connet for Desktop. Why you tell me that my project is out-of-tree?

Best

Marco

RE: No device found with bt_le_scan_start and observer

Simonr — Tue, 20 Dec 2022 07:03:50 GMT

Hi Marco

When building application out of the tree like you do (outside the NCS), the rules are a little different, and my colleague Torsten has written an explanation in this ticket with some dos and don'ts whn adding child images to out-of-tree sources.

This is the only thing I can think of causing a message "scanning successfully started" without actually seeing any advertising devices.

Best regards,

Simon