Directed Advertising not seen by the addressed device

[Ignacio]

Hi,

I am testing direct advertising with two nRF52-DK. One performs a direct advertising and the other scans for the directed adverts. Unfortunately, the scanning device cannot see the directed advertising packages.

For simplicty and to reduce variables, I have set a test where I use the below code on a nRF52 dk (nRF52832) and the BLE tool on the nRF Connect SDK for Desktop (using a nRF52840-donge). I have hardcoded the dongle address on the directed advertiser code. Unfortunately, I still cannot see the directed advertising packages. Why is that? Any help most welcome.

Fullscreen 2742.CMakeLists.txt Download

#
# Copyright (c) 2021 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#
cmake_minimum_required(VERSION 3.20.0)
find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(11_directed_adv)

# NORDIC SDK APP START
target_sources(app PRIVATE
  src/main.c
)
# NORDIC SDK APP END

prj.conf file:

#
# Copyright (c) 2019 Nordic Semiconductor ASA
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#
#CONFIG_NCS_SAMPLES_DEFAULTS=y
CONFIG_BOARD_ENABLE_DCDC=n

CONFIG_BT=y
CONFIG_BT_DEBUG_LOG=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_EXT_ADV=y
CONFIG_BT_DEVICE_NAME="directed_adv"
CONFIG_BT_PRIVACY=n
CONFIG_BT_EXT_ADV_MAX_ADV_SET=1

CONFIG_BT_GATT_CLIENT=y

CONFIG_BT_SETTINGS=y

CONFIG_HEAP_MEM_POOL_SIZE=1024

CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FLASH_MAP=y
CONFIG_NVS=y
CONFIG_SETTINGS=y


# RTT Log Enanble
CONFIG_LOG=y
CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BUFFER_SIZE=4096
CONFIG_RTT_CONSOLE=y
CONFIG_PRINTK=y

Fullscreen 5074.main.c Download

/*
 * Copyright (c) 2019 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

/** @file
 *  @brief Nordic Battery Service Client sample
 */

#include <zephyr/types.h>

#include <errno.h>
#include <sys/printk.h>

#include <bluetooth/bluetooth.h>
#include <bluetooth/gatt.h>
//#include <bluetooth/gatt_dm.h>
#include <bluetooth/uuid.h>

#include <settings/settings.h>

#include <logging/log.h>


#define BT_GAP_ADV_INT_MIN        0x0020  /* 20 ms */
#define BT_GAP_ADV_INT_MAX        0x0020  /* 20 ms */

#define BT_ADV_5S_TIMEOUT         0x01F4  /* N=500 ;  Time = N * 10ms = 5s */
#define BT_ADV_30S_TIMEOUT        0x0BB8  /* N=3000 ; Time = N * 10ms = 30s */
#define BT_ADV_60S_TIMEOUT        0x1770  /* N=6000 ; Time = N * 10ms = 60s */


static uint8_t manu_data[7] = {   0xff, 0x3a,   /* Manufacturer */
                                  0x00, 0x00,   /* Major */
                                  0x00, 0x00,   /* Minor */
                                  0x00};        /* Nb of hops */

static const struct bt_data directed_b2b_ad[] = {
	BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_LIMITED | BT_LE_AD_NO_BREDR)),
        BT_DATA_BYTES(BT_DATA_UUID16_ALL, BT_UUID_16_ENCODE(0xFFFE)),
        BT_DATA(BT_DATA_MANUFACTURER_DATA, &manu_data, sizeof(manu_data)),
};

static bt_addr_le_t connecting_peer_addr;

static struct bt_le_adv_param directed_b2b_param =
                                      BT_LE_ADV_PARAM_INIT( BT_LE_ADV_OPT_CONNECTABLE | BT_LE_ADV_OPT_ONE_TIME | BT_LE_ADV_OPT_USE_NAME |
                                                            BT_LE_ADV_OPT_EXT_ADV | BT_LE_ADV_OPT_DIR_MODE_LOW_DUTY,
                                      BT_GAP_ADV_FAST_INT_MIN_2, \
                                      BT_GAP_ADV_FAST_INT_MAX_2, &connecting_peer_addr);


static struct bt_le_ext_adv *directed_b2b_adv;

//==============================================================================
// advertising: directed
//==============================================================================

static void directed_b2b_adv_sent(struct bt_le_ext_adv *adv,
                     struct bt_le_ext_adv_sent_info *info)
{
  printk("Directed B2B adv timeout\n");
}

static void directed_b2b_adv_connected(struct bt_le_ext_adv *adv,
			  struct bt_le_ext_adv_connected_info *info)
{
  printk("Directed B2B Connected\n");
}

static struct bt_le_ext_adv_cb directed_b2b_adv_callbacks =
{
  .sent = directed_b2b_adv_sent,
  .connected = directed_b2b_adv_connected,
  .scanned = NULL
};
      
//==============================================================================
// bt_ready bluetooth init
//==============================================================================

static void bt_ready(int err)
{
  // TODO: Handle  init errors
  if (err) {
    printk("Bluetooth init failed (err %d)\n", err);
    return;
  }

  printk("Bluetooth initialized\n");

  if (IS_ENABLED(CONFIG_SETTINGS)) {
          settings_load();
  }

  // Directed B2B Advetising Create
  err = bt_le_ext_adv_create(&directed_b2b_param, &directed_b2b_adv_callbacks, &directed_b2b_adv);
  if (err)
  {
    printk("Failed to create directed advertiser set (%d)", err);
    return;
  }

  // set extended directed B2B advertising data
  err = bt_le_ext_adv_set_data(directed_b2b_adv, directed_b2b_ad, ARRAY_SIZE(directed_b2b_ad), NULL, 0);
  if (err)
  {
    printk("Failed to set directed advertising data (%d)", err);
    return;
  }
  
  struct bt_le_ext_adv_start_param directed_b2b_adv_start_param = {
                                    .timeout = BT_ADV_30S_TIMEOUT, 
                                    .num_events = 0};
   
  connecting_peer_addr.type = 0x01;
  connecting_peer_addr.a.val[0] = 0xf0;
  connecting_peer_addr.a.val[1] = 0x0f;
  connecting_peer_addr.a.val[2] = 0x34;
  connecting_peer_addr.a.val[3] = 0x56;
  connecting_peer_addr.a.val[4] = 0x45;
  connecting_peer_addr.a.val[5] = 0xc7;

  directed_b2b_param.peer = &connecting_peer_addr;
  err = bt_le_ext_adv_update_param(directed_b2b_adv, &directed_b2b_param);
  if (err)
  {
    printk("Failed to update directed advertising data (%d)", err);
    return;
  }
  
  err = bt_le_ext_adv_start(directed_b2b_adv, &directed_b2b_adv_start_param);
  if (err)
  {
    printk("Failed to start Directed advertising(%d)\n", err);
    return;
  }
  
  char addr[BT_ADDR_LE_STR_LEN];
  bt_addr_le_to_str(directed_b2b_param.peer, addr, sizeof(addr));
  printk("Directed B2B Advertising Started addr: %s\n", addr);

}

//==============================================================================
// main
//==============================================================================

void main(void)
{
  int err;

  printk("11-directed_adv init\n");

  err = bt_enable(bt_ready);
  if (err) {
          printk("Bluetooth init failed (err %d)\n", err);
          return;
  }
}

Direct Advertiser logs

*** Booting Zephyr OS build v2.7.0-ncs1  ***
11-directed_adv init
[00:00:01.327,239] <inf> fs_nvs: 6 Sectors of 4096 bytes
[00:00:01.327,270] <inf> fs_nvs: alloc wra: 0, f70
[00:00:01.327,270] <inf> fs_nvs: data wra: 0, 118
[00:00:01.327,392] <inf> sdc_hci_driver: SoftDevice Controller build revision: 
                                         df c0 4e d6 1f 7c 66 09  0a f5 2b a0 98 f2 43 64 |..N..|f. ..+...Cd
                                         62 c5 a6 2a                                      |b..*             
[00:00:01.330,413] <inf> bt_hci_core: HW Platform: Nordic Semiconductor (0x0002)
[00:00:01.330,413] <inf> bt_hci_core: HW Variant: nRF52x (0x0002)
[00:00:01.330,413] <inf> bt_hci_core: Firmware: Standard Bluetooth controller (0x00) Version 223.20160 Build 1719410646
[00:00:01.330,718] <inf> bt_hci_core: No ID address. App must call settings_load()
Bluetooth initialized
[00:00:01.330,902] <err> settings: set-value failure. key: bt/keys/e394a91ee9ef1 error(-2)
[00:00:01.331,634] <inf> bt_hci_core: Identity: F2:A4:36:CA:06:73 (random)
[00:00:01.331,634] <inf> bt_hci_core: HCI: version 5.2 (0x0b) revision 0x12b0, manufacturer 0x0059
[00:00:01.331,634] <inf> bt_hci_core: LMP: version 5.2 (0x0b) subver 0x12b0
Directed B2B Advertising Started addr: C7:45:56:34:0F:F0 (random)

BLE Tool

[Ignacio]

Thanks for your reply Torbjørn.

Let's see if we can find some common ground for a solution. I need to set a directed advertising with a timeout.

1. First implmentation. I use bt_le_ext_adv_start. That function allows to specify an advertising timeout using bt_le_ext_adv_start_param:

int bt_le_ext_adv_start(struct bt_le_ext_adv *adv,
			struct bt_le_ext_adv_start_param *param)

However, it seems that it is not possible to discern at the scanner side if an extended advertisement is directed or not. Is that correct?

2. Second implementation. Using the standard advertising function bt_le_adv_start. However, that function does not define any configuration for specifying an advertising timeout:

int bt_le_adv_start(const struct bt_le_adv_param *param,
		    const struct bt_data *ad, size_t ad_len,
		    const struct bt_data *sd, size_t sd_len)

Is it possible to implement a standard directed advertising with a timeout?

Thanks

[Ignacio]

Hi Torbjørn,

I finally got it to work. A couple of comments for others to come.

1. Two config parameters were missing on my prj.conf:

CONFIG_BT_EXT_ADV=y
CONFIG_BT_SCAN_WITH_IDENTITY=y

2. Standard or extended directed advertisments can be filter using the advertising PDU properties:

if(device_info->recv_info->adv_props & BT_GAP_ADV_PROP_DIRECTED)

Torbjørn if you confirm this is correct, I will verify this answer.

Thanks for your help!

[ovrebekk]

Hi Armand

I am happy to hear you figured it out

The check of the adv_props field looks correct, yes. This should filter out directed advertise packets, regardless of whether or not extended advertising is used. 

Best regards
Torbjørn

[Ignacio]

Many thanks for your help!