Custom service is advertised with NUS base UUID

[masterLee]

Dear all,

I use nRF52840 custom board with nRF52 SDK and I want to advertise two more services:

• one custom service (0x1523)
• one battery service (0x180F)

and read them through my mobile with nRF Connect app.

I experiment with the ble_app_uart example (since I want to stream various data after connection with the mobile).

The problem is that the custom service, although it is advertised along with the battery service and the Nordic Uart Service (NUS),
it does not have the 128 bit UUID that I set to it but instead it gets the UUID of the NUS as you can see in the following image.

Obviously I am doing something wrong here but I can't figure out what it is...

Here are the changes  that I have performed in main.c. First I added the custom service UUID  in the list along with its type (128bit)

#define CUSTOM_UUID_BASE {0x23, 0xD1, 0xBC, 0xEA, 0x5F, 0x78, 0x23, 0x15, 0xEF, 0xD6, 0x31, 0xBE, 0x00, 0x00, 0x15, 0x16}
#define CUSTOM_SERVICE_UUID 0x1523

static ble_uuid_t m_adv_uuids[]   =                                  
{
   {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE},
   {BLE_UUID_BATTERY_SERVICE, BLE_UUID_TYPE_BLE},
   {CUSTOM_SERVICE_UUID, BLE_UUID_TYPE_VENDOR_BEGIN}
};

and then I enabled init.config.ble_adv_extended_enabled flag in advertising_init()

static void advertising_init(void)
{
    uint32_t err_code;
    ble_advertising_init_t init;

    memset(&init, 0, sizeof(init));

    init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance = true;
    init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;  //BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;
    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;
    

    //init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    //init.srdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_extended_enabled = true;
    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;
    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}

[Einar Thorsrud]

Hi,

In order to get the correct base UUID you need to register it with sd_ble_uuid_vs_add(). And when you do, the second parameter is an output, and this is the type you need to use when you subsequently refer to it (this is a counter though, so if the base used by NUS is added first this will be 2 (BLE_UUID_TYPE_VENDOR_BEGIN), and your will be 3, so you can use this as well, but then things will break if the order you register the base addresses change).

[masterLee]

Update: I added the following code in services_init(), in sdk_config I set NRF_SDH_BLE_VS_UUID_CNT to 2 and updated the ram size but the result is the same again.

    ret_code_t  err_code;
    ble_uuid_t ble_uuid;
    uint16_t service_handle;
    uint8_t  uuid_type = 0;

    ble_uuid128_t base_uuid = CUSTOM_UUID_BASE;
    err_code = sd_ble_uuid_vs_add(&base_uuid, &uuid_type);
    if (err_code != NRF_SUCCESS) {
      NRF_LOG_INFO("CUSTOM SERVICE ERROR %X| UUID TYPE: %X",err_code ,uuid_type);
    }
    NRF_LOG_INFO(" UUID TYPE: %X",uuid_type);  // returns 3

    ble_uuid.type = uuid_type;
    ble_uuid.uuid = CUSTOM_SERVICE_UUID;   //0x1523

    // Add the service.
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                        &ble_uuid,
                                        &service_handle);
   
    if (err_code != NRF_SUCCESS) {
        NRF_LOG_INFO("CUSTOM SERVICE ERROR %X| SERVICE HANDLE: %X",err_code ,service_handle);
    }
    NRF_LOG_INFO("SERVICE HANDLE: %X",service_handle); //returns 11

[Einar Thorsrud]

This looks OK with regards to how the service is added to the GATT table. But did you make sure to also update the type where you add the service to the advertising packet? Can you show the updated code you have for that?

[masterLee]

I haven't changed something else in the code. Only the parts I mentioned before.

How do I update the type where you add the service to the advertising packet?

Also, I noticed that when I place the last code part before NUS initialization, both services , NUS and custom service get the UUID of the custom service ...

[Einar Thorsrud]

masterLee said:

I haven't changed something else in the code. Only the parts I mentioned before.

Then you are still using the wrong base for your custom service, and that needs to be updated. NUS_SERVICE_UUID_TYPE is defined to BLE_UUID_TYPE_VENDOR_BEGIN, which is 2. So with this snippet you are using the same base as NUS:

static ble_uuid_t m_adv_uuids[]   =                                  
{
   {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE},
   {BLE_UUID_BATTERY_SERVICE, BLE_UUID_TYPE_BLE},
   {CUSTOM_SERVICE_UUID, BLE_UUID_TYPE_VENDOR_BEGIN}
};

You should use BLE_UUID_TYPE_VENDOR_BEGIN+1 instead (you can define it to something sensible, like is done in the SDK for NUS_SERVICE_UUID_TYPE if you like). Note that te way this is done, the order matters as mentionned before, but that is not a big problem.

[masterLee]

Yes you are right! It worked! Great! Thank you for your support!!

[Einar Thorsrud]

That is good to hear. Thanks for letting me know it worked