static void advertising_init(uint8_t adv_flags)
{
    uint32_t      err_code;
    ble_advdata_t advdata;
    int8_t tx_pow = BLE_GAP_AD_TYPE_TX_POWER_LEVEL; //defined at ble_gap.h

    ble_uuid_t adv_uuids[] = { { BLE_UUID_HUMAN_INTERFACE_DEVICE_SERVICE, BLE_UUID_TYPE_BLE },
                                { BLE_UUID_TX_POWER_SERVICE,BLE_UUID_TYPE_BLE }};

    err_code = sd_ble_gap_address_get(&m_ble_addr);
    APP_ERROR_CHECK(err_code);

    err_code = sd_ble_gap_address_set(BLE_GAP_ADDR_CYCLE_MODE_NONE, &m_ble_addr);
    APP_ERROR_CHECK(err_code);

    // Build and set advertising data
    memset(&advdata, 0, sizeof(advdata));

    advdata.name_type               = BLE_ADVDATA_FULL_NAME;
    advdata.include_appearance      = true;
    advdata.flags.size              = sizeof(adv_flags);
    advdata.flags.p_data            = &adv_flags;
    
    //2015 tx power
    advdata.p_tx_power_level        = &tx_pow;
    
    advdata.uuids_complete.uuid_cnt = sizeof(adv_uuids) / sizeof(adv_uuids[0]);
    advdata.uuids_complete.p_uuids  = adv_uuids;

    err_code = ble_advdata_set(&advdata, NULL);
    APP_ERROR_CHECK(err_code);
}