Unable to discover service

[ilockit_CFR]

Hi,

I'm using SDK5 17.1.0 and SD132 v7.3.0. At the moment I'm developing a central device which scans for a peripheral. I did this a few times before with other devices and never had a problem with it. But now, the central is unable to discover the services of the peripheral. In my db discovery event handler I always get the event IDs for BLE_DB_DISCOVERY_SRV_NOT_FOUND and BLE_DB_DISCOVERY_AVAILABLE. I double checked the custom UUID of the service and it's correct. If I use nrf connect on my mobile phone the discovery is completed without any error. 

My service definition looks like this: 

#define DNC_C_BASE_UUID             {0x48, 0x62, 0x6d, 0x47, 0x20, 0x65, 0x63, 0x6e, 0x61, 0x44, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00} 
#define BLE_UUID_DNC_C_SERVICE      0x1000  // UUID of DNC Client Service

and the service I'm looking for looks like this in nrf connect: UUID: 00001000-2020-4461-6e63-6520476d6248

I found this post, but I'm using the peer manager and I also handled this event. By the way, if I change the UUID and advertising search pattern to another device with a different service, I can find it without problems. At the moment I have no idea what I'm missing. Is there a way in the SDK to see all available services of my device instead of searching for a specific UUID?

Best regards,

Christian

[Turbo J]

You would need to sd_ble_uuid_vs_add() the new UUID in order to be able to discover that service from softdevice. May require linker script changes (RAM_START) in order to make more space available for the SD.

But I strongly recommend ditching SDK17.x.y in order to use the newer NRF connect SDK.

[ilockit_CFR]

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

[Kenneth]

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

[ilockit_CFR]

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

[Kenneth]

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

[ilockit_CFR]

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

[Kenneth]

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