Scan UUID increase after each scanning periods

[huaminhtuan]

Hi everyone,

I am using board PCA10040 v1.1.0, softdevice 13.0.0, Eclipse Oxygen. I am trying to scan my phone and communicate with it but the scaned UUID is increasing as you can see in the image below.

Here is the ble_evt_handler function:

static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    ble_gap_evt_t const * p_gap_evt = &p_ble_evt->evt.gap_evt;
    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            PrintInfo("BLE GAP event: Connected");
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            PrintInfo("BLE GAP event: Disconnected");
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            break;

        case BLE_GAP_EVT_ADV_REPORT:
        {
            // The advertisement report
            ble_gap_evt_adv_report_t const * p_adv_report = &p_gap_evt->params.adv_report;
            if(is_uuid_present(m_scan_uuids, p_adv_report))
            {

            }
        }
            break;

        default:
            // No implementation needed.
            break;
    }
}

The is_uuid_presentfunction is as same as the code in the "ble_app_uart_c" example, I just add below code to that:

else if (field_type == BLE_GAP_AD_TYPE_MANUFACTURER_SPECIFIC_DATA)
{
    err_code = sd_ble_uuid_decode(UUID128_SIZE, &p_data[index + 2], &extracted_uuid);
    PrintDebug("err_code: %X", err_code);
    PrintInfo("Scan UUID: %X", extracted_uuid.uuid);
    if (err_code == NRF_SUCCESS)
    {
        if (   (extracted_uuid.uuid == p_target_uuid->uuid)
            && (extracted_uuid.type == p_target_uuid->type))
        {
            return true;
        }
    }
}

Could you help me please? Thanks

[Sigurd]

Hi,

You are getting error code 5(NRF_ERROR_NOT_FOUND) from the function sd_ble_uuid_decode(),so that is probably what is causing this. You are not actually getting a valid UUID.

Take a look at this post where this issue was solved.

[huaminhtuan]

Hi Sigurd, my central device is nRF52832 chip and my peripheral device is my cell phone, so what is the UUID of my cell phone, which is being scanned, looks like? Is it a 128 bit UUID with type BLE_GAP_AD_TYPE_MANUFACTURER_SPECIFIC_DATA (type code is 255)?

[Sigurd]

It's not certain that you have a UUID configured in the advertising packet. What app do you use on the phone to use it as peripheral? What UUID are you looking for? and why are you doing this when the field type is BLE_GAP_AD_TYPE_MANUFACTURER_SPECIFIC_DATA?

[huaminhtuan]

Hi Sigurd, I turn Bluetooth on my cell phone on and I make it "visible" from another device. Does that mean my Phone is advertising? I tried nRF Connect adveriser function, but it showed me a message that the advertiser function is not available on my device.

[Sigurd]

Yes, when you make the phone "visible" it will advertise. I tested this on my Samsung phone, but it did not contain any UUID, only the "ManufacturerSpecificData" field that told me that it was a Samsung phone.

So it’s expected and correct that the sd_ble_uuid_decode() returns NRF_ERROR_NOT_FOUND in this case.