Scan request with extended advertising

[Kenneth]

Hi,

I'm trying to send and receive scan request/scan response.  The system consists of 2 nrf52840, 1 central and 1 peripheral.  They both advertise and scan on 1M and coded PHY alternately.

I'm trying to get the central to send out a scan request, but the peripheral isn't receiving any scan request.  I have the following on peripheral side:

m_advertising.adv_params.scan_req_notification = 1;

and

          case BLE_GAP_EVT_SCAN_REQ_REPORT:  
          {
              NRF_LOG_INFO("SCAN REQ %d", valid_num_central);

On central side, I have:

static ble_gap_scan_params_t m_scan_params =
{
    .active   = 1, //scan req
    .interval = SCAN_INTERVAL,
    .window   = SCAN_WINDOW,
    .report_incomplete_evts = 0, 
    .extended = 1,
    .timeout           = SCAN_TIMEOUT,
    .scan_phys         = BLE_GAP_PHY_1MBPS | BLE_GAP_PHY_CODED, 
    .filter_policy     = BLE_GAP_SCAN_FP_ACCEPT_ALL,
    .channel_mask      = {0,0,0,0,0x00},
};

#define SCAN_INTERVAL 1280
#define SCAN_WINDOW 640
#define SCAN_TIMEOUT 0 

I'm using SDK 16.0.0, SD S140 7.0.1

Any suggestion would be appreciated.

Thanks,

Ken

[Simonr]

Hi

Can you also show me the advertising parameters, in the scan_req_notification define, it is stated that this parameter is ignored if ble_gap_adv_properties is set to a non-scannable advertising type.

You can also take a sniffer trace to check whether a scan request is actually sent by the central device.

Best regards,

Simon

[Kenneth]

static void advertising_init(uint8_t phy)
{
    ret_code_t             err_code;
    static ble_advdata_manuf_data_t manuf_specific_data;
    static ble_advdata_manuf_data_t srsp_manuf_specific_data;

    manuf_specific_data.company_identifier = COMPANY_IDENTIFIER;
    srsp_manuf_specific_data.company_identifier = COMPANY_IDENTIFIER;

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

    manuf_specific_data.data.p_data = (uint8_t *) m_srespons_info;
    manuf_specific_data.data.size   = APP_SRESPONSE_INFO_LENGTH;
    srsp_manuf_specific_data.data.p_data = (uint8_t *) m_srespons_info;
    srsp_manuf_specific_data.data.size = APP_SRESPONSE_INFO_LENGTH;

    init.advdata.name_type               = BLE_ADVDATA_NO_NAME;
    init.advdata.include_appearance      = false;
    init.advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;
    init.advdata.p_manuf_specific_data = &manuf_specific_data;
//    init.srdata.p_manuf_specific_data = &srsp_manuf_specific_data;
//    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
//    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;
    if(phy == BLE_GAP_PHY_CODED)
    {
        m_advertising.adv_params.primary_phy = BLE_GAP_PHY_CODED;
        m_advertising.adv_params.secondary_phy = BLE_GAP_PHY_CODED;
    }
    else 
    {
        m_advertising.adv_params.primary_phy = BLE_GAP_PHY_1MBPS;
        m_advertising.adv_params.secondary_phy = BLE_GAP_PHY_1MBPS;
    }
//    m_advertising.adv_params.properties.type = BLE_GAP_ADV_TYPE_EXTENDED_NONCONNECTABLE_SCANNABLE_UNDIRECTED;
    m_advertising.adv_params.properties.type = BLE_GAP_ADV_TYPE_EXTENDED_NONCONNECTABLE_SCANNABLE_UNDIRECTED;
//    m_advertising.adv_params.properties.type = BLE_GAP_ADV_TYPE_CONNECTABLE_SCANNABLE_UNDIRECTED;
    m_advertising.adv_params.scan_req_notification = 1;
    m_advertising.adv_params.p_peer_addr     = NULL;    // Undirected advertisement.
    m_advertising.adv_params.filter_policy   = BLE_GAP_ADV_FP_ANY;
    m_advertising.adv_params.interval        = APP_ADV_INTERVAL;
    m_advertising.adv_params.duration        = APP_ADV_DURATION_UNLIMITED;       // Timeout after 60 s
    m_advertising.adv_params.channel_mask[4] = 0x00;

    init.config.ble_adv_whitelist_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.config.ble_adv_slow_enabled = true;
    init.config.ble_adv_slow_interval = APP_SLOW_ADV_INTERVAL;
    init.config.ble_adv_slow_timeout = APP_SLOW_ADV_DURATION;
    init.config.ble_adv_extended_enabled = true;
    if(phy == BLE_GAP_PHY_CODED)
    {
        init.config.ble_adv_primary_phy = BLE_GAP_PHY_CODED;
        init.config.ble_adv_secondary_phy = BLE_GAP_PHY_CODED;
    }
    else
    {
        init.config.ble_adv_primary_phy = BLE_GAP_PHY_1MBPS;
        init.config.ble_adv_secondary_phy = BLE_GAP_PHY_1MBPS;
    }


    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);

    err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_ADV, m_advertising.adv_handle, TX_POWER_LEVEL);
    APP_ERROR_CHECK(err_code);
}


#define APP_ADV_INTERVAL                320                       /**< The advertising interval (in units of 0.625 ms. This value corresponds to 150 ms). */
#define APP_ADV_DURATION_UNLIMITED      0                                           /**< Unlimited period .*/
#define APP_ADV_DURATION                2000                         /**< The advertising duration (60 seconds) in units of 10 milliseconds. */
#define APP_SLOW_ADV_INTERVAL           2400                  /**< The advertising interval (in units of 0.625 ms. This value corresponds to 2000 ms). */
#define APP_SLOW_ADV_DURATION           2000

I don't have a BLE sniffer.  Is there another method of checking central's scan request message?

Regards,

Ken

[Kenneth]

Simon,

I managed to get the sniffer going using one of the DK I have.

PDU type is 0011, which seems to be scan request, correct?

A sniff on peripheral adv package for coded PHY

In extended advertising header, it indicates advertising mode as "Connectable Non-scannable" even though advertising property type is set to BLE_GAP_ADV_TYPE_EXTENDED_NONCONNECTABLE_SCANNABLE_UNDIRECTED.  Correct me if I'm wrong, but scannable means it is able to receive scan request.  I'm not sure why advertising header is showing non-scannable.

Regards,

Ken

[Simonr]

Hi

Sorry, I should have mentioned the nRF Sniffer to you in my reply. The fact that the device still advertises in "NONSCANNABLE" is likely why you're seeing this issue. Are you perhaps calling set_adv_mode_directed_high_duty() somewhere in your application, as that will cause the device to advertise in a "NONSCANNABLE" state. Maybe you haven't compiled and built the peripheral project after you changed the application to use SCANNABLE advertising.

Best regards,

Simon

[Kenneth]

Simon,

My peripheral device does not have high duty advertising. I have clean and rebuilt the project, as well as erase the chip before programming.  Peripheral still does not receive notification for scan request.

Any other suggestions as to why it is advertising in nonscannable?

Regards,

Ken