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]

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.
};

[Joakim Jakobsen]

Hi.

Thanks for sharing your solution, so that others might benefit from it.

Best regards,
Joakim.