Unable to discover service

RE: Unable to discover service

ilockit_CFR — Tue, 03 Jun 2025 08:00:24 GMT

Hi,

the manufacturer provided a bug-fix for this. So this ticket can be closed.

Thanks for the support.

RE: Unable to discover service

Kenneth — Wed, 12 Feb 2025 09:06:51 GMT

Strange, maybe you can try the Bluetooth shell:
https://docs.nordicsemi.com/bundle/ncs-latest/page/zephyr/connectivity/bluetooth/bluetooth-shell.html

At least that one should be easy to test.

Kenneth

RE: Unable to discover service

ilockit_CFR — Wed, 12 Feb 2025 08:55:32 GMT

They already received the sniffing logs. Could it be a solution to implement that project with nrf connect SDK? Is there a method to discover all primary services, like in the nrf connect app for Android?

RE: Unable to discover service

Kenneth — Wed, 12 Feb 2025 08:43:31 GMT

[quote user="ilockit_CFR"]Isn't that exactly what is used in service discovery and doesn't work in our case? In the sniffer logs there is the request "Sent Find By Type Value Request" and the answer "Rcvd Error Response - Attribute Not Found"[/quote]

Yes, can you send them that log also?

Kenneth

RE: Unable to discover service

ilockit_CFR — Wed, 12 Feb 2025 07:05:33 GMT

Hi,

I double-double checked that the uuid is correct. We had contact with the manufacturer of the hardware and the response was, that "Discover primary service by service UUID" is not implemented in that product. To implement that, their BLE chip supplier has to update the protocol stack and I think that won't happen.

We then received the following response from the manufacturer, which I don't fully understand. Maybe you can help me with that.

We do have some promising news: After discussing with the MG126 supplier, we confirmed that their current protocol stack supports the “ATT_FIND_BY_TYPE_VALUE_REQ” protocol. Based on our understanding, Nordic’s nRF chip should also support this service.Would you be able to test this approach with your BLE fob development partner? I’d appreciate any feedback on whether this method could work for your setup.

Isn't that exactly what is used in service discovery and doesn't work in our case? In the sniffer logs there is the request "Sent Find By Type Value Request" and the answer "Rcvd Error Response - Attribute Not Found"

Please excuse me for bothering you with the problem which is not caused by the nrf. But it would be nice if we could somehow find a solution.

Best regards,

Christian

RE: Unable to discover service

Kenneth — Fri, 10 Jan 2025 11:31:34 GMT

Double check the problem is not related to endianess of uuid?

Kenneth

RE: Unable to discover service

ilockit_CFR — Thu, 09 Jan 2025 12:55:22 GMT

Hi Kenneth,

tanks for your reply. If I understood this correctly, it was about setting the service UUID to the stack via sd_ble_uuid_vs_add(). I'm doing this already at application start when I initialise the services. So for me it looks, like the service is still not found at all. In my post above I saw the service UUID and thought that it was found, but I think it was only shown because I set the UUID before with ble_db_discovery_evt_register. Do you have any other idea, that could help?

Best regards,

Christian

RE: Unable to discover service

Kenneth — Thu, 09 Jan 2025 09:44:51 GMT

I could find this thread which I think is relevant:
https://devzone.nordicsemi.com/f/nordic-q-a/3656/s130-custom-uuid-service-discovery

Kenneth

RE: Unable to discover service

ilockit_CFR — Tue, 07 Jan 2025 10:43:07 GMT

Hi Kenneth,

at the moment I'm working further on my solution for this workaround and have an issue with the characteristics.

It seems, that your propposed solution only finds the characteristics of the 16-bit standard services. I couldn't find any characteristics of the custom service. I'm also not 100% sure if this workaround can find the custom service at all, because if I check this:

NRF_LOG_DEBUG("Service count = %d", p_ble_gattc_evt->params.prim_srvc_disc_rsp.count);
    
for(uint8_t i = 0; i < p_ble_gattc_evt->params.prim_srvc_disc_rsp.count; i++)
{
    NRF_LOG_DEBUG("[%d]: %.4X",i, p_ble_gattc_evt->params.prim_srvc_disc_rsp.services[i].uuid.uuid);
}

it will give me this result:

00> Service count = 2
00> [0]: 1800
00> [1]: 180A

Is there anything I can do to get the characteristics of the custom service? Unfortunatelly, there's no response from the vendor to fix this bug, so I have to find a solution to get around this.

Best regards,

Christian

RE: Unable to discover service

Kenneth — Thu, 21 Nov 2024 09:01:55 GMT

Hi Christian,

That was good news!

It is a bit hard to tell what exactly is wrong on the Peripheral side, but it looks like a bug in the implementation of the GATT server. According to Core Spec, Vol 3, Part G "4.4 Primary Service Discovery":

There are two sub-procedures that can be used for primary service discovery: Discover All Primary Services and Discover Primary Service by Service UUID.

It looks like the server doesn't support the second sub-procedure (Discover Primary Service by Service UUID) that uses ATT_FIND_BY_TYPE_VALUE_REQ packet.

You might consider report this as a bug and attach sniffer traces you captured to the Bluetooth Host vendor you use.

Hope that helps,
Kenneth

RE: Unable to discover service

ilockit_CFR — Thu, 21 Nov 2024 06:33:42 GMT

Hi Kenneth,

I'm very happy to tell you, that your suggestion worked. I was able to discover all services on the peripheral.

Do you have an idea what's wrong on the peripheral side? If you could explain this to me, I can give the information to the development team of the peripheral so they can fix the issue on their side.

Thank you very much for your support.

Best regards,

Christian

RE: Unable to discover service

Kenneth — Wed, 20 Nov 2024 08:32:04 GMT

Hi Christian,

This seems like an issue on the peripheral side. But it should be possible to change the behaviour by using sd_ble_gattc_primary_services_discover(.., .., NULL).

Can you try in \components\ble\nrf_ble_gq\nrf_ble_gq.c to change the last parameter to NULL for test? Should be two places in the file.

Kenneth

RE: Unable to discover service

ilockit_CFR — Mon, 18 Nov 2024 09:58:01 GMT

Hi,

I can send you the code, if we could turn this ticket to private.

Actually, I call ble_db_discovery_start(&m_db_disc, p_gap_evt->conn_handle); after receiving the BLE_GAP_EVT_CONNECTED event.

Best regards,

Christian

RE: Unable to discover service

Kenneth — Mon, 18 Nov 2024 09:28:04 GMT

Hi.

Can you send part of your code where you have implemented service discovery?

From my understanding, if you call sd_ble_gattc_primary_services_discover(.., .., NULL) then the softdevice will send ATT_READ_BY_GROUP_TYPE_REQ (similar to phone). Can you check if p_srvc_uuid to NULL when you call sd_ble_gattc_primary_services_discover()?

Best regards,
Kenneth

RE: Unable to discover service

ilockit_CFR — Mon, 18 Nov 2024 07:58:08 GMT

Hi Kenneth,

I tried the delay but the result stays the same. I also tried a larger delay or start the discovery on button press, but nothing worked.

Bonding to the device is not possible. One of the developers of the HMI uses a Puck.js from epruino, which also has a nrf52832 on it, and ithe service discovery works fine for him.

Best regards,

Christian

RE: Unable to discover service

Kenneth — Fri, 15 Nov 2024 11:53:09 GMT

Hi Christian,

There are a few things we want you to try.

If possible delay the service discovery with 100ms.

If possible bond before you do a service discovery.

Kenneth

RE: Unable to discover service

ilockit_CFR — Wed, 13 Nov 2024 07:58:21 GMT

Hi,

here are the wireshark files:

devzone.nordicsemi.com/.../connect_5F00_with_5F00_nrf_5F00_connect_5F00_app.pcapng

devzone.nordicsemi.com/.../discovery_5F00_custom_5F00_service_5F00_failed.pcapng

devzone.nordicsemi.com/.../discovery_5F00_0x1800_5F00_failed.pcapng

devzone.nordicsemi.com/.../discovery_5F00_0x1800_5F00_success_5F00_other_5F00_device.pcapng

Best regards,

Christian

RE: Unable to discover service

Kenneth — Tue, 12 Nov 2024 15:27:05 GMT

Hello,

Is there any way you have saved the wireshark (.pcapng) files?

Kenneth

RE: Unable to discover service

ilockit_CFR — Tue, 12 Nov 2024 14:02:32 GMT

Hi Kenneth,

sorry for the late reply. As requested, I created some sniffer logs while discovering the services. I did four different things:

1. Connect with nrf connect Android app to the HMI and start a service discovery - devzone.nordicsemi.com/.../connect_5F00_with_5F00_nrf_5F00_connect_5F00_app.txt

2. Connect HMI with the nrf52832 and start service discovery for the custom service - devzone.nordicsemi.com/.../discovery_5F00_custom_5F00_service_5F00_failed.txt

3. Connect HMI with the nrf52832 and start service discovery for service 0x1800 - devzone.nordicsemi.com/.../discovery_5F00_0x1800_5F00_failed.txt

4. Connect another device with the nrf52832 and start service discovery for service 0x1800 - devzone.nordicsemi.com/.../discovery_5F00_0x1800_5F00_success_5F00_other_5F00_device.txt

Attempt 2 and 3 were not sucessfull. Attempt 4 found the service on the other device to proof, that the code is working.

I hope this helps.

Best regards,

Christian

RE: Unable to discover service

Kenneth — Thu, 24 Oct 2024 11:33:26 GMT

Hi again,

Are you able to provide a sniffer log of working and failing? E.g. using:
https://www.nordicsemi.com/Products/Development-tools/nRF-Sniffer-for-Bluetooth-LE

Kenneth

RE: Unable to discover service

ilockit_CFR — Wed, 23 Oct 2024 08:02:51 GMT

Hi,

switching to nrf connect SDK would be too complicated for the current task. But I tested the central_bas sample in ncs and adjusted it to the service 0x1800 of the peripheral device. The result was the same as in SDK5. The nrf wasn't able to find any service. But if I connect to another device the service is found. That's very strange and I never experienced such behaviour.

The target device is an HMI of an ebike and was developed by our customer. The build-in BLE chip is a Seeed Studio Wio Lite MG126. The mobile apps which are used to communicate to the HMI are working properly. Is there anything else that I can try?

Best regards,

Christian

RE: Unable to discover service

Kenneth — Tue, 22 Oct 2024 12:17:20 GMT

What can you tell me about the peripheral device you are trying to discover?

I know there have been improvement in service discovery in nRF Connect SDK, the implementation is different and more robust, so you may need to update.

Kenneth

RE: Unable to discover service

ilockit_CFR — Tue, 22 Oct 2024 10:13:12 GMT

Hi,

I did a little bit more testing today and found out, that it's also not possible to detect other services on the device, like 0x1800 or 0x180A. If I use the same code and scan for another device which also provides the 0x1800 service, the serivces discovery succeeds.

Is it possible, that the connection parameter are not correct or is there anything else that can influence the service discovery?

Best regards,

Christian

RE: Unable to discover service

Kenneth — Mon, 21 Oct 2024 11:14:21 GMT

Hello,

I recommend going to nRF Connect SDK if possible, But I assume you are using the database discovery module here:
https://docs.nordicsemi.com/bundle/sdk_nrf5_v17.1.0/page/lib_ble_db_discovery.html

Unfortunately you will need to know the base UUID you want to discover yes:
https://devzone.nordicsemi.com/f/nordic-q-a/21152/db-discovery-failing-with-ble_db_discovery_srv_not_found/82775

Notice that each time you call sd_ble_uuid_vs_add() it will increment the uuid.type. If that is not the problem, then I suspect it's some problem with endianess of base uuid.

Kenneth

RE: Unable to discover service

ilockit_CFR — Mon, 21 Oct 2024 10:19:58 GMT

Thanks for the hint, but the base UUID is already added with sd_ble_uuid_vs_add().