Changing advertising maximum size with BLE extended advertisin

[Gabriel Pinto]

Hello! I'm currently using nRF52 SDK to create a BLE beacon in which I update the advertising data at runtime.

I'm using the provided ble beacon example as a base for my program, I found that if I configure the extended advertising in the advertising initialization, it actually support up 251 bytes in the advertising data, however I don't seem to be able to change the base size past 0x18. 

This is how my advertising_init() function looks like: 

static void advertising_init(void)
{
    uint32_t      err_code;
    
    uint8_t       flags = BLE_GAP_ADV_FLAG_BR_EDR_NOT_SUPPORTED;

    manuf_specific_data.company_identifier = APP_COMPANY_IDENTIFIER;

    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.
    memset(&advdata, 0, sizeof(advdata));

    advdata.name_type             = BLE_ADVDATA_NO_NAME;
    advdata.flags                 = flags;
    advdata.p_manuf_specific_data = &manuf_specific_data;

    // 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_EXTENDED_CONNECTABLE_NONSCANNABLE_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_AUTO;
    m_adv_params.secondary_phy      = BLE_GAP_PHY_AUTO;
    m_adv_params.set_id             = 4;
    m_adv_params.filter_policy      = BLE_GAP_ADV_FP_ANY;

    err_code = ble_advdata_encode(&advdata, m_adv_data.adv_data.p_data, &m_adv_data.adv_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);
}

 

The beacon doesn't let me change its max size however because the following setting doesn't go above 0x18 (24 bytes) or it will output an error:

#define APP_BEACON_INFO_LENGTH          0x17

What am I missing to be able to advertise the 251 bytes? 

Thank you and best regards. 

Gabriel

[Gabriel Pinto]

I just tried it and I get the same result, as can be seen below, it doesn't even recognize it's a Nordic device when compared to the last screenshot I sent.

By the way I'm using the app on Android 13, don't know if that influences anything.

[Vidar Berg]

Ok, so it seems like the problem is on the phone side, and not in the FW. In the nrf connect android app, there is a submenu called "Device Information" which lists the supported BLE features. There you can check what he max. advertising length the phone is supposed to support.

[Gabriel Pinto]

Yes I have already gone through that feature list, it says the max advertising lnegth supported is 1024 so it should be able to display it. 

[Gabriel Pinto]

I will try with other phones in the meantime, this not very likely to affect my application for for 8 extra bytes, thank you for your support.