Scan response data to be added to SDK ble_app_beacon example

[Wim]

How can I add scan response data to the SDK example ble_app_beacon?

[Joakim Jakobsen]

Hi!

The approach might vary depending on what version of the SDK you are working with.

Maybe you could provide a little more information?

SDK version, what device, softdevice version etc. is useful information to add in your questions.

However, you can take a look at our advertising tutorial, and the chapter about the Scan response data.
The tutorial is from one of the older SDK but the approach will be similiar.

Also, the ble_app_uart example adds data to the scan reponse packet, so you can get an idea of how it's done.

Let me know if you have any further questions.
Best regards,
Joakim.

 

[Wim]

I have looked into the ble_app_uart example, but I cannot find the line(s) where the scan response data is set.

I receive

      Advertisement data:    02:01:05:0C:09:4E:6F:72:64:69:63:5F:55:41:52:54   (here at the end is Nordic_UART)

      Scan response data: 11:07:9E:CA:DC:24:0E:E5:A9:E0:93:F3:A3:B5:01:00:40:6E

But where is the scan response data in the code?

Thanks for your help!

[Joakim Jakobsen]

Hi.

If you take a look at line 613-614 of the main.c file.

The ble_app_uart adds the 128-bit UUID to the scan response packet.

If you didn't already, I would suggest that you take a look at the tutorial I referred to in my previous answer.

Best regards,
Joakim.

[Wim]

But in that way, I can only change the bytes "01:00" at the end of the scan response data.

For example:

static ble_uuid_t m_adv_uuids[] =   /**< Universally unique service identifier. */
{
//original:    {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
    {0x5678, NUS_SERVICE_UUID_TYPE} //Now 78:56 in the scan response data
};

Where can I change the first 14 bytes? Is that a 128 bit UUID? Where is it set?

(I looked at your tutorial, but the API's of the older SDKs are different from version 15. And the older SDKs have no support for Segger Embedded Studio)

Thanks for your help!

[Joakim Jakobsen]

Not sure what you are trying to acheive here?

Do you want to change the 128-bit UUID that is already added to the BLE stack's table?

You can take a look at the ble_advdata_t struct to see which data can be added to the scan response data.

As an example:

If we want to transmit the TX-power level in the scan response packet (And not the Vendor Specific UUID) of the ble_app_uart example:

static void advertising_init(void)
{
    uint32_t               err_code;
    ble_advertising_init_t init;
    int8_t tx_power = -4;

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

    init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance = false;
    init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;

    //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.srdata.p_tx_power_level =  &tx_power; 

    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);
}

Let me know if I misunderstood something or you  have further questions.

Best regards,
Joakim.

 

 

[Joakim Jakobsen]

Wim said:

Where can I change the first 14 bytes? Is that a 128 bit UUID? Where is it set?

One of my colleagues has made custom service tutorial available on github.

This tutorial is updated to SDK v15.0.0 and you could take a look at that to a better understanding on how the UUID is added to the BLE stack.

Cheers.

[Wim]

Hi Joakim,

I was looking how to program:

- iBeacon (to be recognized by iOS)

- with scan response data (for additional measurement or other data)

- and connectable (to act as normal BLE peripheral)

I succeeded (after combining your info and single stepping through some code)

Here is my example:

static void advertising_init(void)
{
    uint32_t    err_code;
    uint8_t index;
    uint8_t ch_array[10];
    uint16_t major_value;
    uint16_t minor_value;
    ble_advdata_t advdata;
    ble_advdata_t srdata;
    ble_advdata_manuf_data_t manuf_specific_data;
    ble_advdata_service_data_t service_data_array;

    //Compose iBeacon data. Put the measurement data as major_value and minor_value
    manuf_specific_data.company_identifier = APP_COMPANY_IDENTIFIER; //Apple iBeacon. Others are not recognized by iOS
    index = MAJ_VAL_OFFSET_IN_BEACON_INFO;
    m_beacon_info[index++] = 0xab;//MSB_16(major_value);
    m_beacon_info[index++] = 0xcd;//LSB_16(major_value);
    m_beacon_info[index++] = 0xef;//MSB_16(minor_value);
    m_beacon_info[index++] = MyTime; //LSB_16(minor_value);
    manuf_specific_data.data.p_data = (uint8_t *) m_beacon_info;
    manuf_specific_data.data.size   = APP_BEACON_INFO_LENGTH;

    // Build and set advertising data: flags, manufacturer_specific_data
    memset(&advdata, 0, sizeof(advdata));
    advdata.name_type             = BLE_ADVDATA_NO_NAME; //name will be included in scan response data
    advdata.flags                 = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
    advdata.p_manuf_specific_data = &manuf_specific_data;

    // Build and set scan response data: name, service_data
    memset(&srdata, 0, sizeof(srdata));
    srdata.name_type             = BLE_ADVDATA_SHORT_NAME;
    srdata.short_name_len = 3; // Advertise only first 3 letters of name
    ch_array[0] = 0; //eight interesting bytes
    ch_array[1] = 1;
    ch_array[2] = 2;
    ch_array[3] = 3;
    ch_array[4] = 4;
    ch_array[5] = 5;
    ch_array[6] = 6;
    ch_array[7] = 7;
    service_data_array.service_uuid = 0x5678; //16 bit UUID still TBD
    service_data_array.data.size = 8; 
    service_data_array.data.p_data = ch_array; 
    srdata.service_data_count = 1;
    srdata.p_service_data_array = &service_data_array;

    // Initialize advertising parameters (used when starting advertising).
    memset(&m_adv_params, 0, sizeof(m_adv_params));
    m_adv_params.properties.type = BLE_GAP_ADV_TYPE_CONNECTABLE_SCANNABLE_UNDIRECTED;
    m_adv_params.p_peer_addr     = NULL;    // Undirected advertisement.
    m_adv_params.filter_policy   = BLE_GAP_ADV_FP_ANY;
    m_adv_params.interval        = NON_CONNECTABLE_ADV_INTERVAL;
    m_adv_params.duration        = 0;       // Never time out.
    m_adv_params.primary_phy     = BLE_GAP_PHY_1MBPS;
    m_adv_params.duration        = APP_ADV_DURATION;
    m_adv_params.interval        = APP_ADV_INTERVAL;

    //First encode the advertisement data
    err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_data.len);
    APP_ERROR_CHECK(err_code);
    //Now encode the scan response data
    err_code = ble_advdata_encode(&srdata, m_adv_data.scan_rsp_data.p_data, &m_adv_data.scan_rsp_data.len);
    APP_ERROR_CHECK(err_code);

    err_code = sd_ble_gap_adv_set_configure(&m_adv_handle, &m_adv_data, &m_adv_params);
    APP_ERROR_CHECK(err_code);
    
    nrf_gpio_pin_toggle(NRF_GPIO_PIN_MAP(0, 30));
}

Now my advertisement data is:

02:01:06:1A:FF:59:00:02:15:01:12:23:34:45:56:67:78:89:9A:AB:BC:CD:DE:EF:F0:AB:CD:EF:00:C3

And the scna response data is:

0B:16:78:56:00:01:02:03:04:05:06:07:04:08:45:50:50

I hope it can help other programmers.

Best regards,

Wim

[Wim]

I forgot a few lines of code:

#define APP_BEACON_INFO_LENGTH          0x17                               /**< Total length of information advertised by the Beacon. */
#define APP_ADV_DATA_LENGTH             0x15                               /**< Length of manufacturer specific data in the advertisement. */
#define APP_DEVICE_TYPE                 0x02                               /**< 0x02 refers to Beacon. */
#define APP_MEASURED_RSSI               0xC3                               /**< The Beacon's measured RSSI at 1 meter distance in dBm. */
#define APP_COMPANY_IDENTIFIER          0x0059                             /**< Company identifier for Nordic Semiconductor ASA. as per www.bluetooth.org. */
#define APP_MAJOR_VALUE                 0x01, 0x02                         /**< Major value used to identify Beacons. */
#define APP_MINOR_VALUE                 0x03, 0x04                         /**< Minor value used to identify Beacons. */
#define APP_BEACON_UUID                 0x01, 0x12, 0x23, 0x34, \
                                        0x45, 0x56, 0x67, 0x78, \
                                        0x89, 0x9a, 0xab, 0xbc, \
                                        0xcd, 0xde, 0xef, 0xf0            /**< Proprietary UUID for Beacon. */
#define MAJ_VAL_OFFSET_IN_BEACON_INFO   18                                 /**< Position of the MSB of the Major Value in m_beacon_info array. */

static uint8_t m_beacon_info[APP_BEACON_INFO_LENGTH] =                    /**< Information advertised by the Beacon. */
{
    APP_DEVICE_TYPE,     // Manufacturer specific information. Specifies the device type in this
                         // implementation.
    APP_ADV_DATA_LENGTH, // Manufacturer specific information. Specifies the length of the
                         // manufacturer specific data in this implementation.
    APP_BEACON_UUID,     // 128 bit UUID value.
    APP_MAJOR_VALUE,     // Major arbitrary value that can be used to distinguish between Beacons.
    APP_MINOR_VALUE,     // Minor arbitrary value that can be used to distinguish between Beacons.
    APP_MEASURED_RSSI    // Manufacturer specific information. The Beacon's measured TX power in
                         // this implementation.
};