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

[ovrebekk]

Hi Armand

My apologies, I had back to back meetings today and didn't get time. I will do my best to test this tomorrow and get back to you. 

Best regards
Torbjørn

[Ignacio]

Ok Thanks Torbjørn

[ovrebekk]

Hi Armand

I had a chat with Hung, a colleague of mine, who mentioned that he handled a similar case some time ago (with you possibly). 

He sent me some code that I could use to test this. 

I made some minor changes to his code, and was able to get extended directed advertising working. 

directed_adv_scan.zip

Please note that you have to find the local address of the scanner by looking at the log output, and update the advertiser code to use this address. 

Could you give this code a try and see if it works OK?

Best regards
Torbjørn

[Ignacio]

Hi 

Thanks for your reply. I have been going through the code and it is my understanding that it will detect any extended advertising but it does not discriminate for directed advertising. Please check the flags it is reading on the central_bas2 sample code:

static void scan_filter_no_match(struct bt_scan_device_info *device_info,
				 bool connectable)
{
	int err;
	uint8_t i;
	struct bt_conn *conn;
	char addr[BT_ADDR_LE_STR_LEN];
		bt_addr_le_to_str(device_info->recv_info->addr, addr,
				  sizeof(addr));
	if ((addr[0]=='F')&&(addr[1]=='6'))
	{
		printk("address %s\n",addr);	
		for (i=0;i<device_info->adv_data->len;i++)
		{
			printk("%x",device_info->adv_data->data[i]);
		}		  
		printk("\n");
	}
	if ((device_info->recv_info->adv_type == BT_GAP_ADV_TYPE_EXT_ADV) && 
		(device_info->recv_info->adv_props & BT_GAP_ADV_PROP_EXT_ADV)) {
		bt_addr_le_to_str(device_info->recv_info->addr, addr,
				  sizeof(addr));
		printk("Extended directed advertising received from %s\n", addr);
	}
}

The flags are specific to detect  devices that are performing extended advertising but not exclusively directed advertising:

if ((device_info->recv_info->adv_type == BT_GAP_ADV_TYPE_EXT_ADV) && 
		(device_info->recv_info->adv_props & BT_GAP_ADV_PROP_EXT_ADV))

 

Please check this out.

[ovrebekk]

Hi Armand

This was something I had to add myself to make the directed advertising packets detected properly in the example. 

When doing extended advertising then the adv_type field will no longer indicate whether or not you are receiving a directed or undirected advertising packet, since adv_type is BT_GAP_ADV_TYPE_EXT_ADV for all extended advertising packets. 

Instead I had to check the adv_props field in order to figure out whether or not I was receiving an extended directed advertising packet from my advertiser, rather than some other advertise packet from other advertisers in the area. 

If you want to also be able to read normal directed advertising packets (not using extended advertising) then you need to add a separate check for this. 

Does that answer your question?

Best regards
Torbjørn