Modify ble_app_uart_c example to scan for custom UUID not working

RE: Modify ble_app_uart_c example to scan for custom UUID not working

Vidar Berg — Thu, 26 Sep 2019 09:40:21 GMT

I tested this quickly here and was able to establish connection to a device with 0xFFF0 in the advertisement packet. The only change I made was to modify the m_nus_uuid struct at the beginning of main.c:

/**@brief NUS UUID. */
static ble_uuid_t const m_nus_uuid =
{
    .uuid = 0xFFF0,//BLE_UUID_NUS_SERVICE,
    .type = BLE_UUID_TYPE_BLE
};

Is this what you tried earlier?

The peripheral device I tested with:

RE: Modify ble_app_uart_c example to scan for custom UUID not working

EricDelangis — Tue, 24 Sep 2019 13:01:59 GMT

Yes. The UUID is FFF0.

Thanks

RE: Modify ble_app_uart_c example to scan for custom UUID not working

Vidar Berg — Tue, 24 Sep 2019 12:59:06 GMT

I think the best we have for that is the documenation for the scanner module: Scanning Module. I can also try modifiying an existing example to do the same here. What's the value of the UUID in the adv. packet? is it 0xFFF0?

RE: Modify ble_app_uart_c example to scan for custom UUID not working

EricDelangis — Tue, 24 Sep 2019 12:40:23 GMT

Vidar, I have verified that the peripheral does send only the 16-bit UUID. Can you point me to a blog post that discusses matching the 16-bit UUID?

Thanks,

RE: Modify ble_app_uart_c example to scan for custom UUID not working

EricDelangis — Mon, 23 Sep 2019 17:52:48 GMT

Hi Vidar,

Further investigation shows that I am getting an error 0x..08 in NRF_FAULT_ID_SDK_ERROR when trying to connect by matching "full name".

RE: Modify ble_app_uart_c example to scan for custom UUID not working

EricDelangis — Mon, 23 Sep 2019 14:42:52 GMT

OK, I'll check that out. In the meantime, I've been somewhat successful in matching the "Full Name" and getting to:

static void on_connected_evt(nrf_ble_gatt_t * p_gatt, ble_evt_t const * p_ble_evt)

I haven't traced it past this point yet but the nRF52 DK seems to time out and restarts the scan function before the connection can be completed.

Assuming that they are only broadcasting the 16bit UUID, what function do I call to match it? Do I need to set up any other variables to make that work?

RE: Modify ble_app_uart_c example to scan for custom UUID not working

Vidar Berg — Mon, 23 Sep 2019 08:11:34 GMT

Hi,

Maybe you have done it already, but I would suggest inspecting the advertising packet from the peripheral in nRF connect on Android/iOS and check whether it's advertising the full 128-bit UUID or just the 16-bit Service UUID. I find it a bit strange that it's using the SIG base UUID for a custom service.

RE: Modify ble_app_uart_c example to scan for custom UUID not working

EricDelangis — Fri, 20 Sep 2019 16:36:51 GMT

Hi Vidar,

No such luck. Made changes in two places:

Line 72 - #define BLE_UUID_TYPE_BLE BLE_UUID_TYPE_VENDOR_BEGIN /**< UUID type for the Nordic UART Service (vendor specific). */

Line 88 -

/**@brief NUS UUID. */
static ble_uuid_t const m_nus_uuid =
{
.uuid = BLE_UUID_NUS_SERVICE,
.type = BLE_UUID_TYPE_BLE
};

No apparent change. Unfortunately, it will be difficult to change the Peripheral UUID since we don't have the ability to modify that code. We will need to find a work around on our end.

Thanks,

RE: Modify ble_app_uart_c example to scan for custom UUID not working

Vidar Berg — Fri, 20 Sep 2019 13:14:23 GMT

Hi,

Is there any way you can change the service UUID on the Peripheral/Server? It's using the Bluetooth SIGs base UUID: https://www.bluetooth.com/specifications/assigned-numbers/service-discovery/ which is not allowed for custom services. In any case, I think it will work if you change the uuid.type from NUS_SERVICE_UUID_TYPE to BLE_UUID_TYPE_BLE in main.c