PC-BLE-Driver Descriptor UUID

[LarsJensen]

I am trying to implement a system / integration test of a BLE device.

I would like to use the nRF52840-Dongle in my PC and use the PC-BLE-Driver for Cpp as the Central.

So far the Heart Rate Monitor and Heart Rate Collector examples are working for me, but this uses only predefined services.

I am now using the NRF52-DK with the NordicSDK/examples\ble_peripheral\ble_app_blinky Example as this uses Custom Vendor servies with 128 bit.

When i connect to the Blinky pheripheral with nRF Connect i can see verything.

The Nordic LED Button Services with a characteristic and a characteristic descriptor UUID 0x2902.

When i have implemented this service in the HRC, i can discover the services and chacteristics.

When i discover the characteristic UUID i get a different UUID, 0x2803 instead of the 0x2902 as shown in nRF Connect.

Descriptor handle: 0x000C, UUID: 0x2803

The outcome is that i cannot enable notifations, although that should be possible with this example as it is also possible from my phone.

Have anyone experienced this or know why this happends?

[Vidar Berg]

Hello,

In order to interface with custom 128-bit services you will need to add the 128-bit base UUID to the Softdevice through the sd_ble_uuid_vs_add() function first. Unfortunately, I haven't found any ready made examples that demonstrates how this can be done with the pc-ble-driver. But it looks like the necessary steps are covered by this post: https://devzone.nordicsemi.com/f/nordic-q-a/60891/unable-to-read-the-128-bit-uuid-with-base-uuid.  Just let me know if you run into any problems.

[LarsJensen]

Hi Vidar,

I have added the Services as described in the post 

/**@Brief 128-bit UUID Nordic Blinky service*/
static ble_uuid128_t nordic_Service128Uuid = { 0x23,0xd1,0xbc,0xea,0x5f,0x78,0x23,0x15,0xde,0xef,0x12,0x12,0x23,0x15,0x00,0x00 };
static ble_uuid_t nordic_Service = { 0x1523,BLE_UUID_TYPE_VENDOR_BEGIN };

static ble_uuid128_t nordic_button_Characteristic128Uuid = { 0x23,0xd1,0xbc,0xea,0x5f,0x78,0x23,0x15,0xde,0xef,0x12,0x12,0x24,0x15,0x00,0x00 };
static ble_uuid_t nordic_button_Characteristic = { 0x1524,BLE_UUID_TYPE_VENDOR_BEGIN };

error_code = sd_ble_uuid_vs_add(m_adapter, &nordic_Service128Uuid, &nordic_Service.type);

This enables me to discover the services, from that i can discover the caracteristic descriptor, but when i do i get UUID 0x2803.

When i use nRF Connect on my phone i get an UUID 0x2902.

[Vidar Berg]

Hi,

0x2803 is the uuid used for Characteristic declarations. I.e., you are at the beginning of a new characteristic. You can then continue the descriptor discovery until you discover 0x2902 (remember to increment the ATT handle for each time as illustrated here GATTC Descriptor Discovery).

I made a blinky client project based on the existing HRS collector example to try this out myself, please see attached below.

5417.blinky_client.zip

[LarsJensen]

Hi Vidar,

Thank you very much for your help, this was exactly my problem.

Your example worked perfectly and i i think iwould be great if it was included in in PC BLE Driver.