Discovering problem for different 128-bit service and characteristic uuid as a central device

[secondbest]

Hello;

I am using NRF51822 with SDK12.3 as a central device. I want to discover and connect a peripheral bluetooth device by using my NRF51822 central device.

If the service and characteristic is the same, for example service uuid is "00002234-b38d-4985-720e-0f993a68ee41" and characteristic uuid is "00002235-b38d-4985-720e-0f993a68ee41" , I can enable the notification of the characteristic and NRF51 get data from this peripheral device by using this characteristic.

However, If the service and characteristic is the different, for example service uuid is "680c21d9-c946-4c1f-9c11-baa1c21329e7" and characteristic uuid is "003bbdf2-c634-4b3d-ab56-7ec889b89a37", I can connect to this device but NRF51 discovers all characteristics as 0x00 and cannot enable the notification.

Is there a way to handle this problem?

Thanks.

[Dominic]

Can we get a clear answer from someone on the Nordic team whether this is a known limitation for nrf52-based central devices?

I am trying to interface the nrf52 with a BLE pulse oximeter. One of its custom services has the following UUIDs:

Service UUID: 0x46A970E00D5F11E28B5E0002A5D5C51B

      Char 1 UUID: 0x0AAD7EA00D60AAE28E3C0002A5D5C51B

      Char 2 UUID: 0x34E2786376FF4F8E96F19E3993AA6199

I have added all associated service and char UUIDs with sd_ble_uuid_vs_add() and scan for all services by calling sd_ble_gattc_primary_services_discover(conn_handle, disc_start_handle, NULL);

Services with characteristics that share the same base UUID are discovered correctly, but services such as the example above resolve to 0 for their UUID and type.

Is there any way to resolve services with different base UUIDs in their characteristics?

Thanks

[Bjørn Kvaale]

Sorry for the delayed response. I have been on a business trip last week & am now on vacation. I would please suggest you to open a new devzone case regarding this query. It may take slightly longer to reply to DevZone cases this week, as DevZone is understaffed due to Easter break.

[secondbest]

Okey. Thanks.

[Nandi]

I am sorry, I thought that the problem here is not closed, I can still ask questions here, because the same problem to create a new case for devzone is just an increase in workload. . .

[Nandi]

About the nrf SDK UUID has been well understood, and the problem has been solved. If you haven't solved it yet, I can share it with you. The computer is not there for the past few days.

[secondbest]

I haven't solved it yet. Could you share your solution? Thanks Nandi

[Nandi]

ble_app_uart_central.patch

This is changed in your ble_app_uart_c example based on your uuid, you can try it.
The UUID mechanism of the SDK is to add a 128bit base uuid through the sd_ble_uuid_vs_add function. After adding, it will return a UUID type. The subscript is incremented from BLE_UUID_TYPE_VENDOR_BEGIN. For example, after debugging add the characteristic base uuid, it returns uuid_type = 2. When the peripheral is connected, you can see To p_chars[i].characteristic.uuid.type = 2 in the ble_nus_c_on_db_disc_evt function
P_chars[i].characteristic.uuid.uuid = 0xbdf2, service base uuid is the same.