How to set a device as a reflector when running the nrf_dm example?

Question

When I was running the dm process of Connect SDK 3.0.2. I wanted to make one device as the initiator and six devices as the reflectors. I expect that the reflectors will not undergo scanning.I made the modifications based on this post: https://devzone.nordicsemi.com/f/nordic-q-a/99676/customising-distance-measurement-using-ndt/426102?focus=true#permalink=858951*/ for reflector. 
 I made the following revisions to the code of the reflector device:: 
 In the main, these two positions have been commented out : 
 
 and if ( peer_supported_test ( info -> addr )) {}, Also, modify the method for obtaining the random seed 
 
 At the same time, comment out the following code in the peer file: 
 After I completed the two code modifications, I downloaded the code to the reflectors side. But at this point, distance measurement is impossible. Could you please tell me where the problem lies?.

Einar Thorsrud · Accepted Answer

Hi, There are some changes there that I do not understand. Also, there is need for some changes on the initiator side as well to get synchronization working. Please see this modified maiin.c from the nrf_dm sample in nRF Connect SDK 3.0.2: Fullscreen 71536.main.c Download /* * Copyright (c) 2021 Nordic Semiconductor ASA * * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause */ /** @file * @brief Nordic Distance Measurement sample */ #include #include #include #include #include #include #include #include #include #include "peer.h" #include "service.h" #define DEVICE_NAME CONFIG_BT_DEVICE_NAME #define DEVICE_NAME_LEN (sizeof(DEVICE_NAME) - 1) #define RUN_STATUS_LED DK_LED2 #define CON_STATUS_LED DK_LED3 #define RUN_LED_BLINK_INTERVAL 1000 #define SUPPORT_DM_CODE 0xFF55AA5A #define SCAN_ENABLE 0 struct adv_mfg_data { uint16_t company_code; /* Company Identifier Code. */ uint32_t support_dm_code; /* To identify the device that supports distance measurement. */ uint32_t rng_seed; /* Random seed used for generating hopping patterns. */ } __packed; static struct adv_mfg_data mfg_data; struct bt_le_adv_param adv_param_conn = BT_LE_ADV_PARAM_INIT(BT_LE_ADV_OPT_CONN | BT_LE_ADV_OPT_NOTIFY_SCAN_REQ, BT_GAP_ADV_FAST_INT_MIN_2, BT_GAP_ADV_FAST_INT_MAX_2, NULL); struct bt_le_adv_param adv_param_noconn = BT_LE_ADV_PARAM_INIT(BT_LE_ADV_OPT_USE_IDENTITY | BT_LE_ADV_OPT_SCANNABLE | BT_LE_ADV_OPT_NOTIFY_SCAN_REQ, BT_GAP_ADV_FAST_INT_MIN_2, BT_GAP_ADV_FAST_INT_MAX_2, NULL); struct bt_le_adv_param *adv_param = &adv_param_conn; static const struct bt_data ad[] = { BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)), BT_DATA(BT_DATA_NAME_COMPLETE, DEVICE_NAME, DEVICE_NAME_LEN), }; static const struct bt_data sd[] = { BT_DATA(BT_DATA_MANUFACTURER_DATA, (unsigned char *)&mfg_data, sizeof(mfg_data)), BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_DDFS_VAL), }; #if SCAN_ENABLE static struct bt_le_scan_param scan_param = { .type = BT_LE_SCAN_TYPE_ACTIVE, .interval = BT_GAP_SCAN_FAST_INTERVAL, .window = BT_GAP_SCAN_FAST_WINDOW, .options = BT_LE_SCAN_OPT_NONE, .timeout = 0, }; static struct bt_scan_init_param scan_init = { .connect_if_match = 0, .scan_param = &scan_param, .conn_param = NULL }; #endif //static uint32_t scanner_random_share; static struct bt_le_ext_adv *adv; static void adv_work_handle(struct k_work *item); static K_WORK_DEFINE(adv_work, adv_work_handle); static void adv_update_data(void); //static uint32_t scanner_addr_to_random_share(const bt_addr_t *p_scanner_addr); //static uint32_t get_id_addr_random_share(void); #if SCAN_ENABLE static struct bt_scan_manufacturer_data scan_mfg_data = { .data = (unsigned char *)&mfg_data, .data_len = sizeof(mfg_data.company_code) + sizeof(mfg_data.support_dm_code), }; static bool data_cb(struct bt_data *data, void *user_data) { struct adv_mfg_data *recv_mfg_data; struct dm_request req; switch (data->type) { case BT_DATA_MANUFACTURER_DATA: if (sizeof(struct adv_mfg_data) == data->data_len) { recv_mfg_data = (struct adv_mfg_data *)data->data; bt_addr_le_copy(&req.bt_addr, user_data); req.role = DM_ROLE_INITIATOR; req.ranging_mode = peer_ranging_mode_get(); /* We need to make sure that we only initiate a ranging to a single peer. * A scan response that is received by this device can be received by * multiple other devices which can all start a ranging at the same time * as a consequence. To prevent this, we need to make sure that we set a * per-peer random as the random seed. This helps the ranging library to * avoid interference from other devices trying to range at the same time. * * This means that the initiator and the reflector need to set the same * value for the random seed. */ req.rng_seed = sys_le32_to_cpu(recv_mfg_data->rng_seed);// + scanner_random_share; req.start_delay_us = 0; req.extra_window_time_us = 0; dm_request_add(&req); } return false; default: return true; } } #endif #if 0 static uint32_t get_id_addr_random_share(void) { bt_addr_le_t addrs[CONFIG_BT_ID_MAX]; size_t count = CONFIG_BT_ID_MAX; bt_id_get(addrs, &count); __ASSERT(count == 1, "The sample assumes a single ID addr"); return scanner_addr_to_random_share(&addrs[0].a); } static uint32_t scanner_addr_to_random_share(const bt_addr_t *p_scanner_addr) { return (p_scanner_addr->val[0] | p_scanner_addr->val[1] << 8 | p_scanner_addr->val[2] << 16 | p_scanner_addr->val[3] << 24) + (p_scanner_addr->val[4] | p_scanner_addr->val[5] << 8); } #endif #if SCAN_ENABLE static void scan_filter_match(struct bt_scan_device_info *device_info, struct bt_scan_filter_match *filter_match, bool connectable) { bt_addr_le_t addr; bt_addr_le_copy(&addr, device_info->recv_info->addr); peer_supported_add(device_info->recv_info->addr); bt_data_parse(device_info->adv_data, data_cb, &addr); } BT_SCAN_CB_INIT(scan_cb, scan_filter_match, NULL, NULL, NULL); #endif static void adv_scanned_cb(struct bt_le_ext_adv *adv, struct bt_le_ext_adv_scanned_info *info) { struct dm_request req; #if SCAN_ENABLE if (peer_supported_test(info->addr)) { #endif bt_addr_le_copy(&req.bt_addr, info->addr); req.role = DM_ROLE_REFLECTOR; req.ranging_mode = peer_ranging_mode_get(); /* We need to make sure that we only initiate a ranging to a single peer. * A scan response from this device can be received by multiple peers which can * all start a ranging at the same time as a consequence. To prevent this, * we need to make sure that we set a per-peer random as the random seed. * This helps the ranging library to avoid interference from other devices * trying to range at the same time. * * This means that the initiator and the reflector need to set the same value * for the random seed. */ req.rng_seed = peer_rng_seed_get();// + scanner_addr_to_random_share(&info->addr->a); req.start_delay_us = 0; req.extra_window_time_us = 0; dm_request_add(&req); adv_update_data(); #if SCAN_ENABLE } #endif } const static struct bt_le_ext_adv_cb adv_cb = { .scanned = adv_scanned_cb, }; static void adv_update_data(void) { int err; if (!adv) { return; } mfg_data.rng_seed = peer_rng_seed_prepare(); err = bt_le_ext_adv_set_data(adv, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd)); if (err) { printk("Failed setting adv data (err %d) ", err); } } static int adv_start(void) { int err; struct bt_le_ext_adv_start_param ext_adv_start_param = {0}; if (adv) { err = bt_le_ext_adv_stop(adv); if (err) { printk("Failed to stop extended advertising (err %d) ", err); return err; } err = bt_le_ext_adv_delete(adv); if (err) { printk("Failed to delete advertising set (err %d) ", err); return err; } } err = bt_le_ext_adv_create(adv_param, &adv_cb, &adv); if (err) { printk("Failed to create advertising set (err %d) ", err); return err; } err = bt_le_ext_adv_set_data(adv, ad, ARRAY_SIZE(ad), sd, ARRAY_SIZE(sd)); if (err) { printk("Failed setting adv data (err %d) ", err); return err; } err = bt_le_ext_adv_start(adv, &ext_adv_start_param); if (err) { printk("Failed to start extended advertising (err %d) ", err); return err; } return err; } #if SCAN_ENABLE static int scan_start(void) { int err; bt_scan_init(&scan_init); bt_scan_cb_register(&scan_cb); err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_MANUFACTURER_DATA, &scan_mfg_data); if (err) { printk("Scanning filters cannot be set (err %d) ", err); return err; } err = bt_scan_filter_enable(BT_SCAN_MANUFACTURER_DATA_FILTER, false); if (err) { printk("Filters cannot be turned on (err %d) ", err); return err; } //scanner_random_share = get_id_addr_random_share(); err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE); if (err) { printk("Scanning failed to start (err %d) ", err); return err; } return err; } #endif static void adv_work_handle(struct k_work *item) { adv_start(); } static void connected(struct bt_conn *conn, uint8_t conn_err) { adv_param = &adv_param_noconn; k_work_submit(&adv_work); dk_set_led_on(CON_STATUS_LED); } static void disconnected(struct bt_conn *conn, uint8_t reason) { adv_param = &adv_param_conn; k_work_submit(&adv_work); dk_set_led_off(CON_STATUS_LED); } BT_CONN_CB_DEFINE(conn_callbacks) = { .connected = connected, .disconnected = disconnected, }; static int bt_sync_init(void) { /* Synchronisation is based on advertising and scanning modes. * It occurs when SCAN_REQ and SCAN_RESP packets are exchanged. */ int err; printk("DM Bluetooth LE Synchronization initialization "); mfg_data.company_code = sys_cpu_to_le16(CONFIG_BT_COMPANY_ID_NORDIC); mfg_data.support_dm_code = sys_cpu_to_le32(SUPPORT_DM_CODE); mfg_data.rng_seed = sys_cpu_to_le32(peer_rng_seed_prepare()); err = adv_start(); if (err) { printk("Failed to start advertising (err %d) ", err); return err; } #if SCAN_ENABLE err = scan_start(); if (err) { printk("Failed to start scanning (err %d) ", err); } #endif return err; } static void data_ready(struct dm_result *result) { if (result->status) { peer_update(result); } } static struct dm_cb dm_cb = { .data_ready = data_ready, }; int main(void) { int err; uint32_t blink_status = 0; struct dm_init_param init_param; printk("Starting Distance Measurement sample "); err = dk_leds_init(); if (err) { printk("LEDs init failed (err %d) ", err); return 0; } err = peer_init(); if (err) { printk("Peer init failed (err %d) ", err); return 0; } init_param.cb = &dm_cb; err = dm_init(&init_param); if (err) { printk("Distance measurement init failed (err %d) ", err); return 0; } err = service_ddfs_init(); if (err) { printk("DDF Service init failed (err %d) ", err); return 0; } err = bt_enable(NULL); if (err) { printk("Bluetooth init failed (err %d) ", err); return 0; } err = bt_sync_init(); if (err) { printk("Synchronisation init failed (err %d) ", err); return 0; } for (;;) { dk_set_led(RUN_STATUS_LED, (++blink_status) % 2); k_sleep(K_MSEC(RUN_LED_BLINK_INTERVAL)); service_azimuth_elevation_simulation(); } } Also just the diff for simplicity: Fullscreen 5633.main.c.diff Download diff --git a/samples/bluetooth/nrf_dm/src/main.c b/samples/bluetooth/nrf_dm/src/main.c index ccb650a8e9..67305d8c0e 100644 --- a/samples/bluetooth/nrf_dm/src/main.c +++ b/samples/bluetooth/nrf_dm/src/main.c @@ -32,6 +32,8 @@ #define SUPPORT_DM_CODE 0xFF55AA5A +#define SCAN_ENABLE 0 + struct adv_mfg_data { uint16_t company_code; /* Company Identifier Code. */ uint32_t support_dm_code; /* To identify the device that supports distance measurement. */ @@ -67,6 +69,7 @@ static const struct bt_data sd[] = { BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_DDFS_VAL), }; +#if SCAN_ENABLE static struct bt_le_scan_param scan_param = { .type = BT_LE_SCAN_TYPE_ACTIVE, .interval = BT_GAP_SCAN_FAST_INTERVAL, @@ -80,21 +83,24 @@ static struct bt_scan_init_param scan_init = { .scan_param = &scan_param, .conn_param = NULL }; +#endif -static uint32_t scanner_random_share; +//static uint32_t scanner_random_share; static struct bt_le_ext_adv *adv; static void adv_work_handle(struct k_work *item); static K_WORK_DEFINE(adv_work, adv_work_handle); static void adv_update_data(void); -static uint32_t scanner_addr_to_random_share(const bt_addr_t *p_scanner_addr); -static uint32_t get_id_addr_random_share(void); +//static uint32_t scanner_addr_to_random_share(const bt_addr_t *p_scanner_addr); +//static uint32_t get_id_addr_random_share(void); +#if SCAN_ENABLE static struct bt_scan_manufacturer_data scan_mfg_data = { .data = (unsigned char *)&mfg_data, .data_len = sizeof(mfg_data.company_code) + sizeof(mfg_data.support_dm_code), }; + static bool data_cb(struct bt_data *data, void *user_data) { struct adv_mfg_data *recv_mfg_data; @@ -119,7 +125,7 @@ static bool data_cb(struct bt_data *data, void *user_data) * value for the random seed. */ req.rng_seed = - sys_le32_to_cpu(recv_mfg_data->rng_seed) + scanner_random_share; + sys_le32_to_cpu(recv_mfg_data->rng_seed);// + scanner_random_share; req.start_delay_us = 0; req.extra_window_time_us = 0; @@ -130,7 +136,8 @@ static bool data_cb(struct bt_data *data, void *user_data) return true; } } - +#endif +#if 0 static uint32_t get_id_addr_random_share(void) { bt_addr_le_t addrs[CONFIG_BT_ID_MAX]; @@ -149,7 +156,9 @@ static uint32_t scanner_addr_to_random_share(const bt_addr_t *p_scanner_addr) p_scanner_addr->val[2] << 16 | p_scanner_addr->val[3] << 24) + (p_scanner_addr->val[4] | p_scanner_addr->val[5] << 8); } +#endif +#if SCAN_ENABLE static void scan_filter_match(struct bt_scan_device_info *device_info, struct bt_scan_filter_match *filter_match, bool connectable) @@ -162,13 +171,15 @@ static void scan_filter_match(struct bt_scan_device_info *device_info, } BT_SCAN_CB_INIT(scan_cb, scan_filter_match, NULL, NULL, NULL); +#endif static void adv_scanned_cb(struct bt_le_ext_adv *adv, struct bt_le_ext_adv_scanned_info *info) { struct dm_request req; - +#if SCAN_ENABLE if (peer_supported_test(info->addr)) { +#endif bt_addr_le_copy(&req.bt_addr, info->addr); req.role = DM_ROLE_REFLECTOR; req.ranging_mode = peer_ranging_mode_get(); @@ -183,13 +194,15 @@ static void adv_scanned_cb(struct bt_le_ext_adv *adv, * This means that the initiator and the reflector need to set the same value * for the random seed. */ - req.rng_seed = peer_rng_seed_get() + scanner_addr_to_random_share(&info->addr->a); + req.rng_seed = peer_rng_seed_get();// + scanner_addr_to_random_share(&info->addr->a); req.start_delay_us = 0; req.extra_window_time_us = 0; dm_request_add(&req); adv_update_data(); +#if SCAN_ENABLE } +#endif } const static struct bt_le_ext_adv_cb adv_cb = { @@ -249,6 +262,7 @@ static int adv_start(void) return err; } +#if SCAN_ENABLE static int scan_start(void) { int err; @@ -268,7 +282,7 @@ static int scan_start(void) return err; } - scanner_random_share = get_id_addr_random_share(); + //scanner_random_share = get_id_addr_random_share(); err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE); if (err) { @@ -278,6 +292,7 @@ static int scan_start(void) return err; } +#endif static void adv_work_handle(struct k_work *item) { @@ -325,10 +340,12 @@ static int bt_sync_init(void) return err; } +#if SCAN_ENABLE err = scan_start(); if (err) { printk("Failed to start scanning (err %d) ", err); } +#endif return err; } With this, make sure you build with SCAN_ENABLE set to 1 for the firmware to run on the initiator, and set it to 0 for the firmware to run on the reflector where you do not want scanning. Note that with SCAN_ENABLE set to 1 the device is still multirole as in the sample and will work in the same way except for not using a per-peer random seed.

How to set a device as a reflector when running the nrf_dm example?

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