NUS central device return bt_hci_core: opcode 0x1405 status 0x02

Hi 

I have two nRF52833 development boards: one is using BLE peripheral_uart, and the other is used as RX (BLE central_uart). My issue is that, with the TX setup being completely identical, when I use ble_app_uart_c from the nRF5 SDK, it correctly receives the signal and prints the RSSI. However, when I use central_uart from NCS, if it is the first time connect to the peripheral it can print out the RSSI; but if I press reset button for the central device, it will return bt_hci_core: opcode 0x1405 status 0x02.

My code is:

/*
 * Copyright (c) 2018 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

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

#include <errno.h>
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/sys/byteorder.h>
#include <zephyr/sys/printk.h>

#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/hci.h>
#include <zephyr/bluetooth/conn.h>
#include <zephyr/bluetooth/uuid.h>
#include <zephyr/bluetooth/gatt.h>

#include <bluetooth/services/nus.h>
#include <bluetooth/services/nus_client.h>
#include <bluetooth/gatt_dm.h>
#include <bluetooth/scan.h>

#include <zephyr/settings/settings.h>

#include <zephyr/drivers/uart.h>

#include <zephyr/logging/log.h>

#include <zephyr/bluetooth/hci.h>


#define LOG_MODULE_NAME central_uart
LOG_MODULE_REGISTER(LOG_MODULE_NAME);

/* UART payload buffer element size. */
#define UART_BUF_SIZE 45

#define KEY_PASSKEY_ACCEPT DK_BTN1_MSK
#define KEY_PASSKEY_REJECT DK_BTN2_MSK

#define NUS_WRITE_TIMEOUT K_MSEC(150)
#define UART_WAIT_FOR_BUF_DELAY K_MSEC(50)
#define UART_RX_TIMEOUT 50000 /* Wait for RX complete event time in microseconds. */

static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_nus_uart));
static struct k_work_delayable uart_work;

K_SEM_DEFINE(nus_write_sem, 0, 1);

struct uart_data_t {
	void *fifo_reserved;
	uint8_t  data[UART_BUF_SIZE];
	uint16_t len;
};

static K_FIFO_DEFINE(fifo_uart_tx_data);
static K_FIFO_DEFINE(fifo_uart_rx_data);

static struct bt_conn *default_conn;
static struct bt_nus_client nus_client;







static char last_received_data[UART_BUF_SIZE] = {0};
static uint16_t last_received_data_len = 0;
static struct k_work_delayable rssi_work;

// static void rssi_work_handler(struct k_work *work)
// {
//     struct bt_conn_info info;
//     struct net_buf *buf = NULL, *rsp = NULL;
//     struct bt_hci_cp_read_rssi *cp;
//     struct bt_hci_rp_read_rssi *rp;
//     int err;
	
// 	if (default_conn) {
//         struct bt_conn_info info;
//         int err;

//         // 获取当前连接信息
//         err = bt_conn_get_info(default_conn, &info);
//         if (err) {
//             LOG_ERR("Failed to get connection info (err %d)", err);
//             return;
//         }

//         // 创建HCI命令缓冲区以读取RSSI
//         struct net_buf *buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(uint16_t));
//         if (!buf) {
//             LOG_ERR("Failed to create HCI command buffer");
//             return;
//         }

//         // 填充HCI命令
//         struct bt_hci_cp_read_rssi *cp = net_buf_add(buf, sizeof(*cp));
//         cp->handle = sys_cpu_to_le16(info.id);

//         // 发送命令并解析响应
//         struct net_buf *rsp;
//         err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
//         if (err) {
//             LOG_ERR("Failed to read RSSI (err %d)", err);
//             return;
//         }

//         struct bt_hci_rp_read_rssi *rp = (void *)rsp->data;
//         LOG_INF("RSSI: %d dBm", rp->rssi);
// 		LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);

//         net_buf_unref(rsp);
//     }

//     // 调度下一次任务
//     k_work_reschedule(&rssi_work, K_SECONDS(1));  // 每秒读取一次RSSI
// }
static void rssi_work_handler(struct k_work *work)
{
    struct bt_conn_info info;
    struct net_buf *buf = NULL, *rsp = NULL;
    struct bt_hci_cp_read_rssi *cp;
    struct bt_hci_rp_read_rssi *rp;
    int err;

    if (!default_conn) {
        LOG_ERR("No default connection available");
        goto schedule;
    }

    /* 获取当前连接信息 */
    err = bt_conn_get_info(default_conn, &info);
    if (err) {
        LOG_ERR("Failed to get connection info (err %d)", err);
        goto schedule;
    }

    /* 创建 HCI 命令缓冲区以读取 RSSI */
    buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(*cp));
    if (!buf) {
        LOG_ERR("Unable to allocate HCI command buffer");
        goto schedule;
    }

    /* 填充 HCI 命令数据(使用连接标识 info.id 作为句柄) */
    cp = net_buf_add(buf, sizeof(*cp));
    cp->handle = sys_cpu_to_le16(info.id);

    /* 发送 HCI 命令并等待同步响应 */
    err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
    if (err) {
        LOG_ERR("Read RSSI error: %d", err);
        goto schedule;
    }

    /* 解析并打印 RSSI 数据 */
    rp = (void *)rsp->data;
    LOG_INF("RSSI: %d dBm", rp->rssi);
	LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);

    net_buf_unref(rsp);

schedule:
    /* 调度下一次任务:每秒读取一次 RSSI */
    k_work_reschedule(&rssi_work, K_SECONDS(1));
}










static void ble_data_sent(struct bt_nus_client *nus, uint8_t err,
					const uint8_t *const data, uint16_t len)
{
	ARG_UNUSED(nus);
	ARG_UNUSED(data);
	ARG_UNUSED(len);

	k_sem_give(&nus_write_sem);

	if (err) {
		LOG_WRN("ATT error code: 0x%02X", err);
	}
}

// static uint8_t ble_data_received(struct bt_nus_client *nus,
// 						const uint8_t *data, uint16_t len)
// {
// 	ARG_UNUSED(nus);

// 	int err;

// 	for (uint16_t pos = 0; pos != len;) {
// 		struct uart_data_t *tx = k_malloc(sizeof(*tx));

// 		if (!tx) {
// 			LOG_WRN("Not able to allocate UART send data buffer");
// 			return BT_GATT_ITER_CONTINUE;
// 		}

// 		/* Keep the last byte of TX buffer for potential LF char. */
// 		size_t tx_data_size = sizeof(tx->data) - 1;

// 		if ((len - pos) > tx_data_size) {
// 			tx->len = tx_data_size;
// 		} else {
// 			tx->len = (len - pos);
// 		}

// 		memcpy(tx->data, &data[pos], tx->len);

// 		pos += tx->len;

// 		/* Append the LF character when the CR character triggered
// 		 * transmission from the peer.
// 		 */
// 		if ((pos == len) && (data[len - 1] == '\r')) {
// 			tx->data[tx->len] = '\n';
// 			tx->len++;
// 		}

// 		err = uart_tx(uart, tx->data, tx->len, SYS_FOREVER_MS);
// 		if (err) {
// 			k_fifo_put(&fifo_uart_tx_data, tx);
// 		}
// 	}

// 	return BT_GATT_ITER_CONTINUE;
// }






static uint8_t ble_data_received(struct bt_nus_client *nus,
                                 const uint8_t *data, uint16_t len)
{
    ARG_UNUSED(nus);

    // 保存接收到的数据
    memset(last_received_data, 0, sizeof(last_received_data));
    last_received_data_len = len < UART_BUF_SIZE ? len : UART_BUF_SIZE - 1;
    memcpy(last_received_data, data, last_received_data_len);

    //LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);

    return BT_GATT_ITER_CONTINUE;
}









static void uart_cb(const struct device *dev, struct uart_event *evt, void *user_data)
{
	ARG_UNUSED(dev);

	static size_t aborted_len;
	struct uart_data_t *buf;
	static uint8_t *aborted_buf;
	static bool disable_req;

	switch (evt->type) {
	case UART_TX_DONE:
		LOG_DBG("UART_TX_DONE");
		if ((evt->data.tx.len == 0) ||
		    (!evt->data.tx.buf)) {
			return;
		}

		if (aborted_buf) {
			buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
					   data[0]);
			aborted_buf = NULL;
			aborted_len = 0;
		} else {
			buf = CONTAINER_OF(evt->data.tx.buf,
					   struct uart_data_t,
					   data[0]);
		}

		k_free(buf);

		buf = k_fifo_get(&fifo_uart_tx_data, K_NO_WAIT);
		if (!buf) {
			return;
		}

		if (uart_tx(uart, buf->data, buf->len, SYS_FOREVER_MS)) {
			LOG_WRN("Failed to send data over UART");
		}

		break;

	case UART_RX_RDY:
		LOG_DBG("UART_RX_RDY");
		buf = CONTAINER_OF(evt->data.rx.buf, struct uart_data_t, data[0]);
		buf->len += evt->data.rx.len;

		if (disable_req) {
			return;
		}

		if ((evt->data.rx.buf[buf->len - 1] == '\n') ||
		    (evt->data.rx.buf[buf->len - 1] == '\r')) {
			disable_req = true;
			uart_rx_disable(uart);
		}

		break;

	case UART_RX_DISABLED:
		LOG_DBG("UART_RX_DISABLED");
		disable_req = false;

		buf = k_malloc(sizeof(*buf));
		if (buf) {
			buf->len = 0;
		} else {
			LOG_WRN("Not able to allocate UART receive buffer");
			k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
			return;
		}

		uart_rx_enable(uart, buf->data, sizeof(buf->data),
			       UART_RX_TIMEOUT);

		break;

	case UART_RX_BUF_REQUEST:
		LOG_DBG("UART_RX_BUF_REQUEST");
		buf = k_malloc(sizeof(*buf));
		if (buf) {
			buf->len = 0;
			uart_rx_buf_rsp(uart, buf->data, sizeof(buf->data));
		} else {
			LOG_WRN("Not able to allocate UART receive buffer");
		}

		break;

	case UART_RX_BUF_RELEASED:
		LOG_DBG("UART_RX_BUF_RELEASED");
		buf = CONTAINER_OF(evt->data.rx_buf.buf, struct uart_data_t,
				   data[0]);

		if (buf->len > 0) {
			k_fifo_put(&fifo_uart_rx_data, buf);
		} else {
			k_free(buf);
		}

		break;

	case UART_TX_ABORTED:
		LOG_DBG("UART_TX_ABORTED");
		if (!aborted_buf) {
			aborted_buf = (uint8_t *)evt->data.tx.buf;
		}

		aborted_len += evt->data.tx.len;
		buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
				   data[0]);

		uart_tx(uart, &buf->data[aborted_len],
			buf->len - aborted_len, SYS_FOREVER_MS);

		break;

	default:
		break;
	}
}

static void uart_work_handler(struct k_work *item)
{
	struct uart_data_t *buf;

	buf = k_malloc(sizeof(*buf));
	if (buf) {
		buf->len = 0;
	} else {
		LOG_WRN("Not able to allocate UART receive buffer");
		k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
		return;
	}

	uart_rx_enable(uart, buf->data, sizeof(buf->data), UART_RX_TIMEOUT);
}

static int uart_init(void)
{
	int err;
	struct uart_data_t *rx;

	if (!device_is_ready(uart)) {
		LOG_ERR("UART device not ready");
		return -ENODEV;
	}

	rx = k_malloc(sizeof(*rx));
	if (rx) {
		rx->len = 0;
	} else {
		return -ENOMEM;
	}

	k_work_init_delayable(&uart_work, uart_work_handler);

	err = uart_callback_set(uart, uart_cb, NULL);
	if (err) {
		return err;
	}

	return uart_rx_enable(uart, rx->data, sizeof(rx->data),
			      UART_RX_TIMEOUT);
}

static void discovery_complete(struct bt_gatt_dm *dm,
			       void *context)
{
	struct bt_nus_client *nus = context;
	LOG_INF("Service discovery completed");

	bt_gatt_dm_data_print(dm);

	bt_nus_handles_assign(dm, nus);
	bt_nus_subscribe_receive(nus);

	bt_gatt_dm_data_release(dm);
}

static void discovery_service_not_found(struct bt_conn *conn,
					void *context)
{
	LOG_INF("Service not found");
}

static void discovery_error(struct bt_conn *conn,
			    int err,
			    void *context)
{
	LOG_WRN("Error while discovering GATT database: (%d)", err);
}

struct bt_gatt_dm_cb discovery_cb = {
	.completed         = discovery_complete,
	.service_not_found = discovery_service_not_found,
	.error_found       = discovery_error,
};

static void gatt_discover(struct bt_conn *conn)
{
	int err;

	if (conn != default_conn) {
		return;
	}

	err = bt_gatt_dm_start(conn,
			       BT_UUID_NUS_SERVICE,
			       &discovery_cb,
			       &nus_client);
	if (err) {
		LOG_ERR("could not start the discovery procedure, error "
			"code: %d", err);
	}
}

static void exchange_func(struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params)
{
	if (!err) {
		LOG_INF("MTU exchange done");
	} else {
		LOG_WRN("MTU exchange failed (err %" PRIu8 ")", err);
	}
}

static void connected(struct bt_conn *conn, uint8_t conn_err)
{
	char addr[BT_ADDR_LE_STR_LEN];
	int err;

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	if (conn_err) {
		LOG_INF("Failed to connect to %s, 0x%02x %s", addr, conn_err,
			bt_hci_err_to_str(conn_err));

		if (default_conn == conn) {
			bt_conn_unref(default_conn);
			default_conn = NULL;

			err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
			if (err) {
				LOG_ERR("Scanning failed to start (err %d)",
					err);
			}
		}

		return;
	}

	LOG_INF("Connected: %s", addr);

	static struct bt_gatt_exchange_params exchange_params;

	exchange_params.func = exchange_func;
	err = bt_gatt_exchange_mtu(conn, &exchange_params);
	if (err) {
		LOG_WRN("MTU exchange failed (err %d)", err);
	}

	err = bt_conn_set_security(conn, BT_SECURITY_L2);
	if (err) {
		LOG_WRN("Failed to set security: %d", err);

		gatt_discover(conn);
	}

	err = bt_scan_stop();
	if ((!err) && (err != -EALREADY)) {
		LOG_ERR("Stop LE scan failed (err %d)", err);
	}

	// 启动任务
    k_work_schedule(&rssi_work, K_NO_WAIT);
}

static void disconnected(struct bt_conn *conn, uint8_t reason)
{
	k_work_cancel_delayable(&rssi_work);  // 取消RSSI任务

	char addr[BT_ADDR_LE_STR_LEN];
	int err;

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_INF("Disconnected: %s, reason 0x%02x %s", addr, reason, bt_hci_err_to_str(reason));
	


	if (default_conn != conn) {
		return;
	}

	bt_conn_unref(default_conn);
	default_conn = NULL;



	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
	if (err) {
		LOG_ERR("Scanning failed to start (err %d)",
			err);
	}

}

static void security_changed(struct bt_conn *conn, bt_security_t level,
			     enum bt_security_err err)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	if (!err) {
		LOG_INF("Security changed: %s level %u", addr, level);
	} else {
		LOG_WRN("Security failed: %s level %u err %d %s", addr, level, err,
			bt_security_err_to_str(err));
			
	}

	gatt_discover(conn);
}

BT_CONN_CB_DEFINE(conn_callbacks) = {
	.connected = connected,
	.disconnected = disconnected,
	.security_changed = security_changed
};

static void scan_filter_match(struct bt_scan_device_info *device_info,
			      struct bt_scan_filter_match *filter_match,
			      bool connectable)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));

	LOG_INF("Filters matched. Address: %s connectable: %d",
		addr, connectable);

		
}

static void scan_connecting_error(struct bt_scan_device_info *device_info)
{
	LOG_WRN("Connecting failed");
}

static void scan_connecting(struct bt_scan_device_info *device_info,
			    struct bt_conn *conn)
{
	default_conn = bt_conn_ref(conn);
}

static int nus_client_init(void)
{
	int err;
	struct bt_nus_client_init_param init = {
		.cb = {
			.received = ble_data_received,
			.sent = ble_data_sent,
		}
	};

	err = bt_nus_client_init(&nus_client, &init);
	if (err) {
		LOG_ERR("NUS Client initialization failed (err %d)", err);
		return err;
	}

	LOG_INF("NUS Client module initialized");
	return err;
}

BT_SCAN_CB_INIT(scan_cb, scan_filter_match, NULL,
		scan_connecting_error, scan_connecting);

static int scan_init(void)
{
	int err;
	struct bt_scan_init_param scan_init = {
		.connect_if_match = 1,
	};

	bt_scan_init(&scan_init);
	bt_scan_cb_register(&scan_cb);

	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_UUID, BT_UUID_NUS_SERVICE);
	if (err) {
		LOG_ERR("Scanning filters cannot be set (err %d)", err);
		return err;
	}

	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_NAME, "Dynamic test beacon"); // 替换为目标设备的名称
    if (err) {
        LOG_ERR("Failed to set name filter (err %d)", err);
        return err;
    }

	err = bt_scan_filter_enable(BT_SCAN_UUID_FILTER|BT_SCAN_NAME_FILTER, false);
	if (err) {
		LOG_ERR("Filters cannot be turned on (err %d)", err);
		return err;
	}

	LOG_INF("Scan module initialized");
	return err;
}


static void auth_cancel(struct bt_conn *conn)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_INF("Pairing cancelled: %s", addr);
}


static void pairing_complete(struct bt_conn *conn, bool bonded)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_INF("Pairing completed: %s, bonded: %d", addr, bonded);
}


static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
{
	char addr[BT_ADDR_LE_STR_LEN];

	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));

	LOG_WRN("Pairing failed conn: %s, reason %d %s", addr, reason,
		bt_security_err_to_str(reason));
}

static struct bt_conn_auth_cb conn_auth_callbacks = {
	.cancel = auth_cancel,
};

static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
	.pairing_complete = pairing_complete,
	.pairing_failed = pairing_failed
};

int main(void)
{
	int err;

	 k_work_init_delayable(&rssi_work, rssi_work_handler);

	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
	if (err) {
		LOG_ERR("Failed to register authorization callbacks.");
		return 0;
	}

	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
	if (err) {
		printk("Failed to register authorization info callbacks.\n");
		return 0;
	}

	err = bt_enable(NULL);
	if (err) {
		LOG_ERR("Bluetooth init failed (err %d)", err);
		return 0;
	}
	LOG_INF("Bluetooth initialized");



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

	err = uart_init();
	if (err != 0) {
		LOG_ERR("uart_init failed (err %d)", err);
		return 0;
	}

	err = scan_init();
	if (err != 0) {
		LOG_ERR("scan_init failed (err %d)", err);
		return 0;
	}

	err = nus_client_init();
	if (err != 0) {
		LOG_ERR("nus_client_init failed (err %d)", err);
		return 0;
	}

	printk("Starting Bluetooth Central UART example\n");

	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
	if (err) {
		LOG_ERR("Scanning failed to start (err %d)", err);
		return 0;
	}

	LOG_INF("Scanning successfully started");

	struct uart_data_t nus_data = {
		.len = 0,
	};

	for (;;) {
		/* Wait indefinitely for data to be sent over Bluetooth */
		struct uart_data_t *buf = k_fifo_get(&fifo_uart_rx_data,
						     K_FOREVER);

		int plen = MIN(sizeof(nus_data.data) - nus_data.len, buf->len);
		int loc = 0;

		while (plen > 0) {
			memcpy(&nus_data.data[nus_data.len], &buf->data[loc], plen);
			nus_data.len += plen;
			loc += plen;
			if (nus_data.len >= sizeof(nus_data.data) ||
			   (nus_data.data[nus_data.len - 1] == '\n') ||
			   (nus_data.data[nus_data.len - 1] == '\r')) {
				err = bt_nus_client_send(&nus_client, nus_data.data, nus_data.len);
				if (err) {
					LOG_WRN("Failed to send data over BLE connection"
						"(err %d)", err);
				}

				err = k_sem_take(&nus_write_sem, NUS_WRITE_TIMEOUT);
				if (err) {
					LOG_WRN("NUS send timeout");
				}

				nus_data.len = 0;
			}

			plen = MIN(sizeof(nus_data.data), buf->len - loc);
		}

		k_free(buf);
	}
}

My config is 

#
# Copyright (c) 2018 Nordic Semiconductor
#
# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
#

# Enable the UART driver
CONFIG_UART_ASYNC_API=y
CONFIG_NRFX_UARTE0=y
CONFIG_SERIAL=y
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

# Enable the BLE stack with GATT Client configuration
CONFIG_BT=y
CONFIG_BT_CENTRAL=y
CONFIG_BT_SMP=y
CONFIG_BT_GATT_CLIENT=y

# Enable the BLE modules from NCS
CONFIG_BT_NUS_CLIENT=y
CONFIG_BT_SCAN=y
CONFIG_BT_SCAN_FILTER_ENABLE=y
CONFIG_BT_SCAN_UUID_CNT=1
CONFIG_BT_SCAN_NAME_CNT=1
CONFIG_BT_GATT_DM=y
CONFIG_HEAP_MEM_POOL_SIZE=2048

# This example requires more stack
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
CONFIG_MAIN_STACK_SIZE=1536

# Enable bonding
CONFIG_BT_SETTINGS=y
CONFIG_FLASH=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_FLASH_MAP=y

# Config logger
CONFIG_LOG=y
CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_LOG_BACKEND_UART=n
CONFIG_LOG_PRINTK=n

CONFIG_ASSERT=y

# RSSI
CONFIG_BT_CTLR_ADVANCED_FEATURES=y
CONFIG_BT_CTLR_CONN_RSSI=y
CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y

# #FEM
# CONFIG_MPSL_FEM=y
# CONFIG_MPSL=y
# # CONFIG_MPSL_FEM_NRF21540_GPIO=y 不需要
# CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y
# CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=20
# CONFIG_MPSL_FEM_NRF21540_RX_GAIN_DB=13

This was I question I try to disscuss here https://devzone.nordicsemi.com/f/nordic-q-a/118265/ble-central_uart-cannot-work-with-nrf21540-ek

Thank you so much for your help!

  • Hi,

    I am sorry for the delay. I am reproducing the same as you and looking into it, but have not got to the bottom of it yet. I will continue to look into it and get back to you.

  • Hi,

    The issue here is that the conn handle provided is incorrect. It is accidentally correct the first time (when the value is zero). Specifically, the way you set p->handle was incorrect. If you modify your rssi_work_handler() function so that it looks like this, it should work (and does so on my end):

    static void rssi_work_handler(struct k_work *work)
    {
        uint16_t conn_handle;
        struct net_buf *buf = NULL, *rsp = NULL;
        struct bt_hci_cp_read_rssi *cp;
        struct bt_hci_rp_read_rssi *rp;
        int err;
    
        if (!default_conn) {
            LOG_ERR("No default connection available");
            goto schedule;
        }
    
        err = bt_hci_get_conn_handle(default_conn, &conn_handle);
        if (err) {
            printk("Failed obtaining conn_handle (err %d)\n", err);
        }
    
        /* 创建 HCI 命令缓冲区以读取 RSSI */
        buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(*cp));
        if (!buf) {
            LOG_ERR("Unable to allocate HCI command buffer");
            goto schedule;
        }
    
        /* 填充 HCI 命令数据(使用连接标识 info.id 作为句柄) */
        cp = net_buf_add(buf, sizeof(*cp));
        cp->handle = sys_cpu_to_le16(conn_handle);
    
        /* 发送 HCI 命令并等待同步响应 */
        err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
        if (err) {
            LOG_ERR("Read RSSI error: %d", err);
            goto schedule;
        }
    
        /* 解析并打印 RSSI 数据 */
        rp = (void *)rsp->data;
        LOG_INF("RSSI: %d dBm", rp->rssi);
    	LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);
    
        net_buf_unref(rsp);
    
    schedule:
        /* 调度下一次任务:每秒读取一次 RSSI */
        k_work_reschedule(&rssi_work, K_SECONDS(1));
    }
    

  • Hi, thank you so much for your information. However, after I change me code into yours, the problem still happen. And I try to delete this rssi_work_handler function and keep my code like this:

    /*
     * Copyright (c) 2018 Nordic Semiconductor ASA
     *
     * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
     */
    
    /** @file
     *  @brief Nordic UART Service Client sample
     */
    
    #include <errno.h>
    #include <zephyr/kernel.h>
    #include <zephyr/device.h>
    #include <zephyr/devicetree.h>
    #include <zephyr/sys/byteorder.h>
    #include <zephyr/sys/printk.h>
    
    #include <zephyr/bluetooth/bluetooth.h>
    #include <zephyr/bluetooth/hci.h>
    #include <zephyr/bluetooth/hci_vs.h>
    #include <zephyr/bluetooth/conn.h>
    #include <zephyr/bluetooth/uuid.h>
    #include <zephyr/bluetooth/gatt.h>
    
    #include <bluetooth/services/nus.h>
    #include <bluetooth/services/nus_client.h>
    #include <bluetooth/gatt_dm.h>
    #include <bluetooth/scan.h>
    
    #include <zephyr/settings/settings.h>
    
    #include <zephyr/drivers/uart.h>
    
    #include <zephyr/logging/log.h>
    
    #include <zephyr/bluetooth/hci.h>
    
    #include "pid.h" // 确保pid.h在项目中
    
    
    #define LOG_MODULE_NAME central_uart
    LOG_MODULE_REGISTER(LOG_MODULE_NAME);
    
    /* UART payload buffer element size. */
    #define UART_BUF_SIZE 45
    
    #define KEY_PASSKEY_ACCEPT DK_BTN1_MSK
    #define KEY_PASSKEY_REJECT DK_BTN2_MSK
    
    #define NUS_WRITE_TIMEOUT K_MSEC(150)
    #define UART_WAIT_FOR_BUF_DELAY K_MSEC(50)
    #define UART_RX_TIMEOUT 50000 /* Wait for RX complete event time in microseconds. */
    
    static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_nus_uart));
    static struct k_work_delayable uart_work;
    
    K_SEM_DEFINE(nus_write_sem, 0, 1);
    
    struct uart_data_t {
    	void *fifo_reserved;
    	uint8_t  data[UART_BUF_SIZE];
    	uint16_t len;
    };
    
    static K_FIFO_DEFINE(fifo_uart_tx_data);
    static K_FIFO_DEFINE(fifo_uart_rx_data);
    
    static struct bt_conn *default_conn;
    static struct bt_nus_client nus_client;
    static uint16_t default_conn_handle;
    
    
    
    
    
    
    static char last_received_data[UART_BUF_SIZE] = {0};
    static uint16_t last_received_data_len = 0;
    static struct k_work_delayable rssi_work;
    
    
    // PID参数
    static struct k_thread pwr_thread_data;
    static K_THREAD_STACK_DEFINE(pwr_thread_stack, 512);
    #define DEVICE_BEACON_TXPOWER_NUM 8
    static const int8_t txpower[DEVICE_BEACON_TXPOWER_NUM] = {4, 0, -3, -8,
    							  -15, -18, -23, -30};
    #define TX_POWER_MAX   8   // 根据设备能力调整
    #define TX_POWER_MIN -30
    #define RSSI_TARGET  -40.0f // 目标RSSI值
    
    
    
    
    
    
    
    static void read_conn_rssi(uint16_t handle, int8_t *rssi)
    {
    	struct net_buf *buf, *rsp = NULL;
    	struct bt_hci_cp_read_rssi *cp;
    	struct bt_hci_rp_read_rssi *rp;
    
    	int err;
    
    	buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(*cp));
    	if (!buf) {
    		printk("Unable to allocate command buffer\n");
    		return;
    	}
    
    	cp = net_buf_add(buf, sizeof(*cp));
    	cp->handle = sys_cpu_to_le16(handle);
    
    	err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
    	if (err) {
    		printk("Read RSSI err: %d\n", err);
    		return;
    	}
    
    	rp = (void *)rsp->data;
    	*rssi = rp->rssi;
    
    	net_buf_unref(rsp);
    }
    
    
    static void set_tx_power(uint8_t handle_type, uint16_t handle, int8_t tx_pwr_lvl)
    {
    	struct bt_hci_cp_vs_write_tx_power_level *cp;
    	struct bt_hci_rp_vs_write_tx_power_level *rp;
    	struct net_buf *buf, *rsp = NULL;
    	int err;
    
    	buf = bt_hci_cmd_create(BT_HCI_OP_VS_WRITE_TX_POWER_LEVEL,
    				sizeof(*cp));
    	if (!buf) {
    		printk("Unable to allocate command buffer\n");
    		return;
    	}
    
    	cp = net_buf_add(buf, sizeof(*cp));
    	cp->handle = sys_cpu_to_le16(handle);
    	cp->handle_type = handle_type;
    	cp->tx_power_level = tx_pwr_lvl;
    
    	err = bt_hci_cmd_send_sync(BT_HCI_OP_VS_WRITE_TX_POWER_LEVEL,
    				   buf, &rsp);
    	if (err) {
    		printk("Set Tx power err: %d\n", err);
    		return;
    	}
    
    	rp = (void *)rsp->data;
    	printk("Actual Tx Power: %d\n", rp->selected_tx_power);
    
    	net_buf_unref(rsp);
    }
    
    static void get_tx_power(uint8_t handle_type, uint16_t handle, int8_t *tx_pwr_lvl)
    {
    	struct bt_hci_cp_vs_read_tx_power_level *cp;
    	struct bt_hci_rp_vs_read_tx_power_level *rp;
    	struct net_buf *buf, *rsp = NULL;
    	int err;
    
    	*tx_pwr_lvl = 0xFF;
    	buf = bt_hci_cmd_create(BT_HCI_OP_VS_READ_TX_POWER_LEVEL,
    				sizeof(*cp));
    	if (!buf) {
    		printk("Unable to allocate command buffer\n");
    		return;
    	}
    
    	cp = net_buf_add(buf, sizeof(*cp));
    	cp->handle = sys_cpu_to_le16(handle);
    	cp->handle_type = handle_type;
    
    	err = bt_hci_cmd_send_sync(BT_HCI_OP_VS_READ_TX_POWER_LEVEL,
    				   buf, &rsp);
    	if (err) {
    		printk("Read Tx power err: %d\n", err);
    		return;
    	}
    
    	rp = (void *)rsp->data;
    	*tx_pwr_lvl = rp->tx_power_level;
    
    	net_buf_unref(rsp);
    }
    
    
    
    
    
    
    
    void modulate_tx_power(void *p1, void *p2, void *p3)
    {
    
    
    	while (1) {
    
    	int err;
    	int8_t rssi = 0xFF;
    	read_conn_rssi(default_conn_handle, &rssi);
    	printk("RSSI: %d dBm\n", rssi);
    	 err = bt_nus_client_send(&nus_client, (uint8_t *)&rssi, sizeof(rssi));
            if (err) {
          LOG_WRN("bt_nus_client_send failed (err %d)", err);}
    
    	k_sleep(K_MSEC(100));}
    }
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    // static void rssi_work_handler(struct k_work *work)
    // {
    //     uint16_t conn_handle;
    //     struct net_buf *buf = NULL, *rsp = NULL;
    //     struct bt_hci_cp_read_rssi *cp;
    //     struct bt_hci_rp_read_rssi *rp;
    //     int err;
    
    //     if (!default_conn) {
    //         LOG_ERR("No default connection available");
    //         goto schedule;
    //     }
    
    //     err = bt_hci_get_conn_handle(default_conn, &conn_handle);
    //     if (err) {
    //         printk("Failed obtaining conn_handle (err %d)\n", err);
    //     }
    
    //     /* 创建 HCI 命令缓冲区以读取 RSSI */
    //     buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(*cp));
    //     if (!buf) {
    //         LOG_ERR("Unable to allocate HCI command buffer");
    //         goto schedule;
    //     }
    
    //     /* 填充 HCI 命令数据(使用连接标识 info.id 作为句柄) */
    //     cp = net_buf_add(buf, sizeof(*cp));
    //     cp->handle = sys_cpu_to_le16(conn_handle);
    
    //     /* 发送 HCI 命令并等待同步响应 */
    //     err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
    //     if (err) {
    //         LOG_ERR("Read RSSI error: %d", err);
    //         goto schedule;
    //     }
    
    //     /* 解析并打印 RSSI 数据 */
    //     rp = (void *)rsp->data;
    //     LOG_INF("RSSI: %d dBm", rp->rssi);
    // 	LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);
    
    //     net_buf_unref(rsp);
    
    // schedule:
    //     /* 调度下一次任务:每秒读取一次 RSSI */
    //     k_work_reschedule(&rssi_work, K_SECONDS(1));
    // }
    
    
    
    
    
    
    
    
    
    
    static void ble_data_sent(struct bt_nus_client *nus, uint8_t err,
    					const uint8_t *const data, uint16_t len)
    {
    	ARG_UNUSED(nus);
    	ARG_UNUSED(data);
    	ARG_UNUSED(len);
    
    	k_sem_give(&nus_write_sem);
    
    	if (err) {
    		LOG_WRN("ATT error code: 0x%02X", err);
    	}
    }
    
    
    
    
    static uint8_t ble_data_received(struct bt_nus_client *nus,
                                     const uint8_t *data, uint16_t len)
    {
        ARG_UNUSED(nus);
    
        // 保存接收到的数据
        memset(last_received_data, 0, sizeof(last_received_data));
        last_received_data_len = len < UART_BUF_SIZE ? len : UART_BUF_SIZE - 1;
        memcpy(last_received_data, data, last_received_data_len);
    
        LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);
    
        return BT_GATT_ITER_CONTINUE;
    }
    
    
    
    
    
    
    
    
    
    static void uart_cb(const struct device *dev, struct uart_event *evt, void *user_data)
    {
    	ARG_UNUSED(dev);
    
    	static size_t aborted_len;
    	struct uart_data_t *buf;
    	static uint8_t *aborted_buf;
    	static bool disable_req;
    
    	switch (evt->type) {
    	case UART_TX_DONE:
    		LOG_DBG("UART_TX_DONE");
    		if ((evt->data.tx.len == 0) ||
    		    (!evt->data.tx.buf)) {
    			return;
    		}
    
    		if (aborted_buf) {
    			buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
    					   data[0]);
    			aborted_buf = NULL;
    			aborted_len = 0;
    		} else {
    			buf = CONTAINER_OF(evt->data.tx.buf,
    					   struct uart_data_t,
    					   data[0]);
    		}
    
    		k_free(buf);
    
    		buf = k_fifo_get(&fifo_uart_tx_data, K_NO_WAIT);
    		if (!buf) {
    			return;
    		}
    
    		if (uart_tx(uart, buf->data, buf->len, SYS_FOREVER_MS)) {
    			LOG_WRN("Failed to send data over UART");
    		}
    
    		break;
    
    	case UART_RX_RDY:
    		LOG_DBG("UART_RX_RDY");
    		buf = CONTAINER_OF(evt->data.rx.buf, struct uart_data_t, data[0]);
    		buf->len += evt->data.rx.len;
    
    		if (disable_req) {
    			return;
    		}
    
    		if ((evt->data.rx.buf[buf->len - 1] == '\n') ||
    		    (evt->data.rx.buf[buf->len - 1] == '\r')) {
    			disable_req = true;
    			uart_rx_disable(uart);
    		}
    
    		break;
    
    	case UART_RX_DISABLED:
    		LOG_DBG("UART_RX_DISABLED");
    		disable_req = false;
    
    		buf = k_malloc(sizeof(*buf));
    		if (buf) {
    			buf->len = 0;
    		} else {
    			LOG_WRN("Not able to allocate UART receive buffer");
    			k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
    			return;
    		}
    
    		uart_rx_enable(uart, buf->data, sizeof(buf->data),
    			       UART_RX_TIMEOUT);
    
    		break;
    
    	case UART_RX_BUF_REQUEST:
    		LOG_DBG("UART_RX_BUF_REQUEST");
    		buf = k_malloc(sizeof(*buf));
    		if (buf) {
    			buf->len = 0;
    			uart_rx_buf_rsp(uart, buf->data, sizeof(buf->data));
    		} else {
    			LOG_WRN("Not able to allocate UART receive buffer");
    		}
    
    		break;
    
    	case UART_RX_BUF_RELEASED:
    		LOG_DBG("UART_RX_BUF_RELEASED");
    		buf = CONTAINER_OF(evt->data.rx_buf.buf, struct uart_data_t,
    				   data[0]);
    
    		if (buf->len > 0) {
    			k_fifo_put(&fifo_uart_rx_data, buf);
    		} else {
    			k_free(buf);
    		}
    
    		break;
    
    	case UART_TX_ABORTED:
    		LOG_DBG("UART_TX_ABORTED");
    		if (!aborted_buf) {
    			aborted_buf = (uint8_t *)evt->data.tx.buf;
    		}
    
    		aborted_len += evt->data.tx.len;
    		buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
    				   data[0]);
    
    		uart_tx(uart, &buf->data[aborted_len],
    			buf->len - aborted_len, SYS_FOREVER_MS);
    
    		break;
    
    	default:
    		break;
    	}
    }
    
    static void uart_work_handler(struct k_work *item)
    {
    	struct uart_data_t *buf;
    
    	buf = k_malloc(sizeof(*buf));
    	if (buf) {
    		buf->len = 0;
    	} else {
    		LOG_WRN("Not able to allocate UART receive buffer");
    		k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
    		return;
    	}
    
    	uart_rx_enable(uart, buf->data, sizeof(buf->data), UART_RX_TIMEOUT);
    }
    
    static int uart_init(void)
    {
    	int err;
    	struct uart_data_t *rx;
    
    	if (!device_is_ready(uart)) {
    		LOG_ERR("UART device not ready");
    		return -ENODEV;
    	}
    
    	rx = k_malloc(sizeof(*rx));
    	if (rx) {
    		rx->len = 0;
    	} else {
    		return -ENOMEM;
    	}
    
    	k_work_init_delayable(&uart_work, uart_work_handler);
    
    	err = uart_callback_set(uart, uart_cb, NULL);
    	if (err) {
    		return err;
    	}
    
    	return uart_rx_enable(uart, rx->data, sizeof(rx->data),
    			      UART_RX_TIMEOUT);
    }
    
    static void discovery_complete(struct bt_gatt_dm *dm,
    			       void *context)
    {
    	struct bt_nus_client *nus = context;
    	LOG_INF("Service discovery completed");
    
    	bt_gatt_dm_data_print(dm);
    
    	bt_nus_handles_assign(dm, nus);
    	bt_nus_subscribe_receive(nus);
    
    	bt_gatt_dm_data_release(dm);
    }
    
    static void discovery_service_not_found(struct bt_conn *conn,
    					void *context)
    {
    	LOG_INF("Service not found");
    }
    
    static void discovery_error(struct bt_conn *conn,
    			    int err,
    			    void *context)
    {
    	LOG_WRN("Error while discovering GATT database: (%d)", err);
    }
    
    struct bt_gatt_dm_cb discovery_cb = {
    	.completed         = discovery_complete,
    	.service_not_found = discovery_service_not_found,
    	.error_found       = discovery_error,
    };
    
    static void gatt_discover(struct bt_conn *conn)
    {
    	int err;
    
    	if (conn != default_conn) {
    		return;
    	}
    
    	err = bt_gatt_dm_start(conn,
    			       BT_UUID_NUS_SERVICE,
    			       &discovery_cb,
    			       &nus_client);
    	if (err) {
    		LOG_ERR("could not start the discovery procedure, error "
    			"code: %d", err);
    	}
    }
    
    static void exchange_func(struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params)
    {
    	if (!err) {
    		LOG_INF("MTU exchange done");
    	} else {
    		LOG_WRN("MTU exchange failed (err %" PRIu8 ")", err);
    	}
    }
    
    static void connected(struct bt_conn *conn, uint8_t conn_err)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    	int err;
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    
    	if (conn_err) {
    		LOG_INF("Failed to connect to %s, 0x%02x %s", addr, conn_err,
    			bt_hci_err_to_str(conn_err));
    
    		if (default_conn == conn) {
    			bt_conn_unref(default_conn);
    
    			default_conn = NULL;
    
    			err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
    			if (err) {
    				LOG_ERR("Scanning failed to start (err %d)",
    					err);
    			}
    		}
    
    		return;
    	}
    
    	default_conn = bt_conn_ref(conn);
    	bt_hci_get_conn_handle(default_conn, &default_conn_handle);
    
    	LOG_INF("Connected: %s", addr);
    
    	static struct bt_gatt_exchange_params exchange_params;
    
    	exchange_params.func = exchange_func;
    	err = bt_gatt_exchange_mtu(conn, &exchange_params);
    	if (err) {
    		LOG_WRN("MTU exchange failed (err %d)", err);
    	}
    
    	err = bt_conn_set_security(conn, BT_SECURITY_L2);
    	if (err) {
    		LOG_WRN("Failed to set security: %d", err);
    
    		gatt_discover(conn);
    	}
    
    	err = bt_scan_stop();
    	if ((!err) && (err != -EALREADY)) {
    		LOG_ERR("Stop LE scan failed (err %d)", err);
    	}
    	//k_work_init_delayable(&rssi_work, rssi_work_handler);
    	// 启动任务
        //k_work_schedule(&rssi_work, K_NO_WAIT);
    }
    
    static void disconnected(struct bt_conn *conn, uint8_t reason)
    {
    	//k_work_cancel_delayable(&rssi_work);  // 取消RSSI任务
    
    	char addr[BT_ADDR_LE_STR_LEN];
    	int err;
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_INF("Disconnected: %s, reason 0x%02x %s", addr, reason, bt_hci_err_to_str(reason));
    	
    
    
    	if (default_conn != conn) {
    		return;
    	}
    
    	bt_conn_unref(default_conn);
    	default_conn = NULL;
    
    
    
    	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
    	if (err) {
    		LOG_ERR("Scanning failed to start (err %d)",
    			err);
    	}
    
    }
    
    static void security_changed(struct bt_conn *conn, bt_security_t level,
    			     enum bt_security_err err)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	if (!err) {
    		LOG_INF("Security changed: %s level %u", addr, level);
    	} else {
    		LOG_WRN("Security failed: %s level %u err %d %s", addr, level, err,
    			bt_security_err_to_str(err));
    			
    	}
    
    	gatt_discover(conn);
    }
    
    BT_CONN_CB_DEFINE(conn_callbacks) = {
    	.connected = connected,
    	.disconnected = disconnected,
    	.security_changed = security_changed
    };
    
    static void scan_filter_match(struct bt_scan_device_info *device_info,
    			      struct bt_scan_filter_match *filter_match,
    			      bool connectable)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));
    
    	LOG_INF("Filters matched. Address: %s connectable: %d",
    		addr, connectable);
    
    		
    }
    
    static void scan_connecting_error(struct bt_scan_device_info *device_info)
    {
    	LOG_WRN("Connecting failed");
    }
    
    static void scan_connecting(struct bt_scan_device_info *device_info,
    			    struct bt_conn *conn)
    {
    	default_conn = bt_conn_ref(conn);
    }
    
    static int nus_client_init(void)
    {
    	int err;
    	struct bt_nus_client_init_param init = {
    		.cb = {
    			.received = ble_data_received,
    			.sent = ble_data_sent,
    		}
    	};
    
    	err = bt_nus_client_init(&nus_client, &init);
    	if (err) {
    		LOG_ERR("NUS Client initialization failed (err %d)", err);
    		return err;
    	}
    
    	LOG_INF("NUS Client module initialized");
    	return err;
    }
    
    BT_SCAN_CB_INIT(scan_cb, scan_filter_match, NULL,
    		scan_connecting_error, scan_connecting);
    
    static int scan_init(void)
    {
    	int err;
    	struct bt_scan_init_param scan_init = {
    		.connect_if_match = 1,
    	};
    
    	bt_scan_init(&scan_init);
    	bt_scan_cb_register(&scan_cb);
    
    	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_UUID, BT_UUID_NUS_SERVICE);
    	if (err) {
    		LOG_ERR("Scanning filters cannot be set (err %d)", err);
    		return err;
    	}
    
    	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_NAME, "Dynamic test beacon"); // 替换为目标设备的名称
        if (err) {
            LOG_ERR("Failed to set name filter (err %d)", err);
            return err;
        }
    
    	err = bt_scan_filter_enable(BT_SCAN_UUID_FILTER|BT_SCAN_NAME_FILTER, false);
    	if (err) {
    		LOG_ERR("Filters cannot be turned on (err %d)", err);
    		return err;
    	}
    
    	LOG_INF("Scan module initialized");
    	return err;
    }
    
    
    static void auth_cancel(struct bt_conn *conn)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_INF("Pairing cancelled: %s", addr);
    }
    
    
    static void pairing_complete(struct bt_conn *conn, bool bonded)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_INF("Pairing completed: %s, bonded: %d", addr, bonded);
    }
    
    
    static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_WRN("Pairing failed conn: %s, reason %d %s", addr, reason,
    		bt_security_err_to_str(reason));
    }
    
    static struct bt_conn_auth_cb conn_auth_callbacks = {
    	.cancel = auth_cancel,
    };
    
    static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
    	.pairing_complete = pairing_complete,
    	.pairing_failed = pairing_failed
    };
    
    int main(void)
    {
    	int err;
    
    	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
    	if (err) {
    		LOG_ERR("Failed to register authorization callbacks.");
    		return 0;
    	}
    
    	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
    	if (err) {
    		printk("Failed to register authorization info callbacks.\n");
    		return 0;
    	}
    
    	err = bt_enable(NULL);
    	if (err) {
    		LOG_ERR("Bluetooth init failed (err %d)", err);
    		return 0;
    	}
    	LOG_INF("Bluetooth initialized");
    
    
    
    	if (IS_ENABLED(CONFIG_SETTINGS)) {
    		settings_load();
    	}
    
    	err = uart_init();
    	if (err != 0) {
    		LOG_ERR("uart_init failed (err %d)", err);
    		return 0;
    	}
    
    	err = scan_init();
    	if (err != 0) {
    		LOG_ERR("scan_init failed (err %d)", err);
    		return 0;
    	}
    
    	err = nus_client_init();
    	if (err != 0) {
    		LOG_ERR("nus_client_init failed (err %d)", err);
    		return 0;
    	}
    
    	printk("Starting Bluetooth Central UART example\n");
    
    	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
    	if (err) {
    		LOG_ERR("Scanning failed to start (err %d)", err);
    		return 0;
    	}
    
    	LOG_INF("Scanning successfully started");
    
    	struct uart_data_t nus_data = {
    		.len = 0,
    	};
    
    	k_thread_create(&pwr_thread_data, pwr_thread_stack,
    			K_THREAD_STACK_SIZEOF(pwr_thread_stack),
    			modulate_tx_power, NULL, NULL, NULL,
    			K_PRIO_COOP(10),
    			0, K_NO_WAIT);
    	k_thread_name_set(&pwr_thread_data, "DYN TX");
    
    	for (;;) {
    		/* Wait indefinitely for data to be sent over Bluetooth */
    		struct uart_data_t *buf = k_fifo_get(&fifo_uart_rx_data,
    						     K_FOREVER);
    
    		int plen = MIN(sizeof(nus_data.data) - nus_data.len, buf->len);
    		int loc = 0;
    
    		while (plen > 0) {
    			memcpy(&nus_data.data[nus_data.len], &buf->data[loc], plen);
    			nus_data.len += plen;
    			loc += plen;
    			if (nus_data.len >= sizeof(nus_data.data) ||
    			   (nus_data.data[nus_data.len - 1] == '\n') ||
    			   (nus_data.data[nus_data.len - 1] == '\r')) {
    				err = bt_nus_client_send(&nus_client, nus_data.data, nus_data.len);
    				if (err) {
    					LOG_WRN("Failed to send data over BLE connection"
    						"(err %d)", err);
    				}
    
    				err = k_sem_take(&nus_write_sem, NUS_WRITE_TIMEOUT);
    				if (err) {
    					LOG_WRN("NUS send timeout");
    				}
    
    				nus_data.len = 0;
    			}
    
    			plen = MIN(sizeof(nus_data.data), buf->len - loc);
    		}
    
    		k_free(buf);
    	}
    }
    

    I still get this opcode 0x1405 after the second connection.

    00> [00:01:02.611,816] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:02.712,188] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm
    00> [00:01:02.712,310] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:02.812,683] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm
    00> [00:01:02.812,774] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:02.913,146] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm
    00> [00:01:02.913,238] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:03.013,610] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm
    00> [00:01:03.013,732] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:03.114,105] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm
    00> [00:01:03.114,196] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:03.214,569] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm
    00> [00:01:03.214,660] <wrn> central_uart: bt_nus_client_send failed (err -128)
    00> [00:01:03.315,032] <wrn> bt_hci_core: opcode 0x1405 status 0x02 
    00> Read RSSI err: -5
    00> RSSI: -1 dBm

     Could you help me to figure out?

  • Hi,

    This code does not even regularily check the RSSI (though you have code in place for it), so I suggest you back-track a bit. For reference, this is the full main.c file I tested which is your previous uploaded main.c with minor modifications. You should be able to run that and see that it works:

    /*
     * Copyright (c) 2018 Nordic Semiconductor ASA
     *
     * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
     */
    
    /** @file
     *  @brief Nordic UART Service Client sample
     */
    
    #include <errno.h>
    #include <zephyr/kernel.h>
    #include <zephyr/device.h>
    #include <zephyr/devicetree.h>
    #include <zephyr/sys/byteorder.h>
    #include <zephyr/sys/printk.h>
    
    #include <zephyr/bluetooth/bluetooth.h>
    #include <zephyr/bluetooth/hci.h>
    #include <zephyr/bluetooth/conn.h>
    #include <zephyr/bluetooth/uuid.h>
    #include <zephyr/bluetooth/gatt.h>
    
    #include <bluetooth/services/nus.h>
    #include <bluetooth/services/nus_client.h>
    #include <bluetooth/gatt_dm.h>
    #include <bluetooth/scan.h>
    
    #include <zephyr/settings/settings.h>
    
    #include <zephyr/drivers/uart.h>
    
    #include <zephyr/logging/log.h>
    
    #include <zephyr/bluetooth/hci.h>
    
    
    #define LOG_MODULE_NAME central_uart
    LOG_MODULE_REGISTER(LOG_MODULE_NAME);
    
    /* UART payload buffer element size. */
    #define UART_BUF_SIZE 45
    
    #define KEY_PASSKEY_ACCEPT DK_BTN1_MSK
    #define KEY_PASSKEY_REJECT DK_BTN2_MSK
    
    #define NUS_WRITE_TIMEOUT K_MSEC(150)
    #define UART_WAIT_FOR_BUF_DELAY K_MSEC(50)
    #define UART_RX_TIMEOUT 50000 /* Wait for RX complete event time in microseconds. */
    
    static const struct device *uart = DEVICE_DT_GET(DT_CHOSEN(nordic_nus_uart));
    static struct k_work_delayable uart_work;
    
    K_SEM_DEFINE(nus_write_sem, 0, 1);
    
    struct uart_data_t {
    	void *fifo_reserved;
    	uint8_t  data[UART_BUF_SIZE];
    	uint16_t len;
    };
    
    static K_FIFO_DEFINE(fifo_uart_tx_data);
    static K_FIFO_DEFINE(fifo_uart_rx_data);
    
    static struct bt_conn *default_conn;
    static struct bt_nus_client nus_client;
    
    
    
    
    
    
    
    static char last_received_data[UART_BUF_SIZE] = {0};
    static uint16_t last_received_data_len = 0;
    static struct k_work_delayable rssi_work;
    
    // static void rssi_work_handler(struct k_work *work)
    // {
    //     struct bt_conn_info info;
    //     struct net_buf *buf = NULL, *rsp = NULL;
    //     struct bt_hci_cp_read_rssi *cp;
    //     struct bt_hci_rp_read_rssi *rp;
    //     int err;
    	
    // 	if (default_conn) {
    //         struct bt_conn_info info;
    //         int err;
    
    //         // 获取当前连接信息
    //         err = bt_conn_get_info(default_conn, &info);
    //         if (err) {
    //             LOG_ERR("Failed to get connection info (err %d)", err);
    //             return;
    //         }
    
    //         // 创建HCI命令缓冲区以读取RSSI
    //         struct net_buf *buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(uint16_t));
    //         if (!buf) {
    //             LOG_ERR("Failed to create HCI command buffer");
    //             return;
    //         }
    
    //         // 填充HCI命令
    //         struct bt_hci_cp_read_rssi *cp = net_buf_add(buf, sizeof(*cp));
    //         cp->handle = sys_cpu_to_le16(info.id);
    
    //         // 发送命令并解析响应
    //         struct net_buf *rsp;
    //         err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
    //         if (err) {
    //             LOG_ERR("Failed to read RSSI (err %d)", err);
    //             return;
    //         }
    
    //         struct bt_hci_rp_read_rssi *rp = (void *)rsp->data;
    //         LOG_INF("RSSI: %d dBm", rp->rssi);
    // 		LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);
    
    //         net_buf_unref(rsp);
    //     }
    
    //     // 调度下一次任务
    //     k_work_reschedule(&rssi_work, K_SECONDS(1));  // 每秒读取一次RSSI
    // }
    static void rssi_work_handler(struct k_work *work)
    {
        uint16_t conn_handle;
        struct net_buf *buf = NULL, *rsp = NULL;
        struct bt_hci_cp_read_rssi *cp;
        struct bt_hci_rp_read_rssi *rp;
        int err;
    
        if (!default_conn) {
            LOG_ERR("No default connection available");
            goto schedule;
        }
    
        err = bt_hci_get_conn_handle(default_conn, &conn_handle);
        if (err) {
            printk("Failed obtaining conn_handle (err %d)\n", err);
        }
    
        /* 创建 HCI 命令缓冲区以读取 RSSI */
        buf = bt_hci_cmd_create(BT_HCI_OP_READ_RSSI, sizeof(*cp));
        if (!buf) {
            LOG_ERR("Unable to allocate HCI command buffer");
            goto schedule;
        }
    
        /* 填充 HCI 命令数据(使用连接标识 info.id 作为句柄) */
        cp = net_buf_add(buf, sizeof(*cp));
        cp->handle = sys_cpu_to_le16(conn_handle);
    
        /* 发送 HCI 命令并等待同步响应 */
        err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_RSSI, buf, &rsp);
        if (err) {
            LOG_ERR("Read RSSI error: %d", err);
            goto schedule;
        }
    
        /* 解析并打印 RSSI 数据 */
        rp = (void *)rsp->data;
        LOG_INF("RSSI: %d dBm", rp->rssi);
    	LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);
    
        net_buf_unref(rsp);
    
    schedule:
        /* 调度下一次任务:每秒读取一次 RSSI */
        k_work_reschedule(&rssi_work, K_SECONDS(1));
    }
    
    
    
    
    
    
    
    
    
    static void ble_data_sent(struct bt_nus_client *nus, uint8_t err,
    					const uint8_t *const data, uint16_t len)
    {
    	ARG_UNUSED(nus);
    	ARG_UNUSED(data);
    	ARG_UNUSED(len);
    
    	k_sem_give(&nus_write_sem);
    
    	if (err) {
    		LOG_WRN("ATT error code: 0x%02X", err);
    	}
    }
    
    // static uint8_t ble_data_received(struct bt_nus_client *nus,
    // 						const uint8_t *data, uint16_t len)
    // {
    // 	ARG_UNUSED(nus);
    
    // 	int err;
    
    // 	for (uint16_t pos = 0; pos != len;) {
    // 		struct uart_data_t *tx = k_malloc(sizeof(*tx));
    
    // 		if (!tx) {
    // 			LOG_WRN("Not able to allocate UART send data buffer");
    // 			return BT_GATT_ITER_CONTINUE;
    // 		}
    
    // 		/* Keep the last byte of TX buffer for potential LF char. */
    // 		size_t tx_data_size = sizeof(tx->data) - 1;
    
    // 		if ((len - pos) > tx_data_size) {
    // 			tx->len = tx_data_size;
    // 		} else {
    // 			tx->len = (len - pos);
    // 		}
    
    // 		memcpy(tx->data, &data[pos], tx->len);
    
    // 		pos += tx->len;
    
    // 		/* Append the LF character when the CR character triggered
    // 		 * transmission from the peer.
    // 		 */
    // 		if ((pos == len) && (data[len - 1] == '\r')) {
    // 			tx->data[tx->len] = '\n';
    // 			tx->len++;
    // 		}
    
    // 		err = uart_tx(uart, tx->data, tx->len, SYS_FOREVER_MS);
    // 		if (err) {
    // 			k_fifo_put(&fifo_uart_tx_data, tx);
    // 		}
    // 	}
    
    // 	return BT_GATT_ITER_CONTINUE;
    // }
    
    
    
    
    
    
    static uint8_t ble_data_received(struct bt_nus_client *nus,
                                     const uint8_t *data, uint16_t len)
    {
        ARG_UNUSED(nus);
    
        // 保存接收到的数据
        memset(last_received_data, 0, sizeof(last_received_data));
        last_received_data_len = len < UART_BUF_SIZE ? len : UART_BUF_SIZE - 1;
        memcpy(last_received_data, data, last_received_data_len);
    
        //LOG_INF("Data received: %.*s", last_received_data_len, last_received_data);
    
        return BT_GATT_ITER_CONTINUE;
    }
    
    
    
    
    
    
    
    
    
    static void uart_cb(const struct device *dev, struct uart_event *evt, void *user_data)
    {
    	ARG_UNUSED(dev);
    
    	static size_t aborted_len;
    	struct uart_data_t *buf;
    	static uint8_t *aborted_buf;
    	static bool disable_req;
    
    	switch (evt->type) {
    	case UART_TX_DONE:
    		LOG_DBG("UART_TX_DONE");
    		if ((evt->data.tx.len == 0) ||
    		    (!evt->data.tx.buf)) {
    			return;
    		}
    
    		if (aborted_buf) {
    			buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
    					   data[0]);
    			aborted_buf = NULL;
    			aborted_len = 0;
    		} else {
    			buf = CONTAINER_OF(evt->data.tx.buf,
    					   struct uart_data_t,
    					   data[0]);
    		}
    
    		k_free(buf);
    
    		buf = k_fifo_get(&fifo_uart_tx_data, K_NO_WAIT);
    		if (!buf) {
    			return;
    		}
    
    		if (uart_tx(uart, buf->data, buf->len, SYS_FOREVER_MS)) {
    			LOG_WRN("Failed to send data over UART");
    		}
    
    		break;
    
    	case UART_RX_RDY:
    		LOG_DBG("UART_RX_RDY");
    		buf = CONTAINER_OF(evt->data.rx.buf, struct uart_data_t, data[0]);
    		buf->len += evt->data.rx.len;
    
    		if (disable_req) {
    			return;
    		}
    
    		if ((evt->data.rx.buf[buf->len - 1] == '\n') ||
    		    (evt->data.rx.buf[buf->len - 1] == '\r')) {
    			disable_req = true;
    			uart_rx_disable(uart);
    		}
    
    		break;
    
    	case UART_RX_DISABLED:
    		LOG_DBG("UART_RX_DISABLED");
    		disable_req = false;
    
    		buf = k_malloc(sizeof(*buf));
    		if (buf) {
    			buf->len = 0;
    		} else {
    			LOG_WRN("Not able to allocate UART receive buffer");
    			k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
    			return;
    		}
    
    		uart_rx_enable(uart, buf->data, sizeof(buf->data),
    			       UART_RX_TIMEOUT);
    
    		break;
    
    	case UART_RX_BUF_REQUEST:
    		LOG_DBG("UART_RX_BUF_REQUEST");
    		buf = k_malloc(sizeof(*buf));
    		if (buf) {
    			buf->len = 0;
    			uart_rx_buf_rsp(uart, buf->data, sizeof(buf->data));
    		} else {
    			LOG_WRN("Not able to allocate UART receive buffer");
    		}
    
    		break;
    
    	case UART_RX_BUF_RELEASED:
    		LOG_DBG("UART_RX_BUF_RELEASED");
    		buf = CONTAINER_OF(evt->data.rx_buf.buf, struct uart_data_t,
    				   data[0]);
    
    		if (buf->len > 0) {
    			k_fifo_put(&fifo_uart_rx_data, buf);
    		} else {
    			k_free(buf);
    		}
    
    		break;
    
    	case UART_TX_ABORTED:
    		LOG_DBG("UART_TX_ABORTED");
    		if (!aborted_buf) {
    			aborted_buf = (uint8_t *)evt->data.tx.buf;
    		}
    
    		aborted_len += evt->data.tx.len;
    		buf = CONTAINER_OF(aborted_buf, struct uart_data_t,
    				   data[0]);
    
    		uart_tx(uart, &buf->data[aborted_len],
    			buf->len - aborted_len, SYS_FOREVER_MS);
    
    		break;
    
    	default:
    		break;
    	}
    }
    
    static void uart_work_handler(struct k_work *item)
    {
    	struct uart_data_t *buf;
    
    	buf = k_malloc(sizeof(*buf));
    	if (buf) {
    		buf->len = 0;
    	} else {
    		LOG_WRN("Not able to allocate UART receive buffer");
    		k_work_reschedule(&uart_work, UART_WAIT_FOR_BUF_DELAY);
    		return;
    	}
    
    	uart_rx_enable(uart, buf->data, sizeof(buf->data), UART_RX_TIMEOUT);
    }
    
    static int uart_init(void)
    {
    	int err;
    	struct uart_data_t *rx;
    
    	if (!device_is_ready(uart)) {
    		LOG_ERR("UART device not ready");
    		return -ENODEV;
    	}
    
    	rx = k_malloc(sizeof(*rx));
    	if (rx) {
    		rx->len = 0;
    	} else {
    		return -ENOMEM;
    	}
    
    	k_work_init_delayable(&uart_work, uart_work_handler);
    
    	err = uart_callback_set(uart, uart_cb, NULL);
    	if (err) {
    		return err;
    	}
    
    	return uart_rx_enable(uart, rx->data, sizeof(rx->data),
    			      UART_RX_TIMEOUT);
    }
    
    static void discovery_complete(struct bt_gatt_dm *dm,
    			       void *context)
    {
    	struct bt_nus_client *nus = context;
    	LOG_INF("Service discovery completed");
    
    	bt_gatt_dm_data_print(dm);
    
    	bt_nus_handles_assign(dm, nus);
    	bt_nus_subscribe_receive(nus);
    
    	bt_gatt_dm_data_release(dm);
    }
    
    static void discovery_service_not_found(struct bt_conn *conn,
    					void *context)
    {
    	LOG_INF("Service not found");
    }
    
    static void discovery_error(struct bt_conn *conn,
    			    int err,
    			    void *context)
    {
    	LOG_WRN("Error while discovering GATT database: (%d)", err);
    }
    
    struct bt_gatt_dm_cb discovery_cb = {
    	.completed         = discovery_complete,
    	.service_not_found = discovery_service_not_found,
    	.error_found       = discovery_error,
    };
    
    static void gatt_discover(struct bt_conn *conn)
    {
    	int err;
    
    	if (conn != default_conn) {
    		return;
    	}
    
    	err = bt_gatt_dm_start(conn,
    			       BT_UUID_NUS_SERVICE,
    			       &discovery_cb,
    			       &nus_client);
    	if (err) {
    		LOG_ERR("could not start the discovery procedure, error "
    			"code: %d", err);
    	}
    }
    
    static void exchange_func(struct bt_conn *conn, uint8_t err, struct bt_gatt_exchange_params *params)
    {
    	if (!err) {
    		LOG_INF("MTU exchange done");
    	} else {
    		LOG_WRN("MTU exchange failed (err %" PRIu8 ")", err);
    	}
    }
    
    static void connected(struct bt_conn *conn, uint8_t conn_err)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    	int err;
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	if (conn_err) {
    		LOG_INF("Failed to connect to %s, 0x%02x %s", addr, conn_err,
    			bt_hci_err_to_str(conn_err));
    
    		if (default_conn == conn) {
    			bt_conn_unref(default_conn);
    			default_conn = NULL;
    
    			err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
    			if (err) {
    				LOG_ERR("Scanning failed to start (err %d)",
    					err);
    			}
    		}
    
    		return;
    	}
    
    	LOG_INF("Connected: %s", addr);
    
    	static struct bt_gatt_exchange_params exchange_params;
    
    	exchange_params.func = exchange_func;
    	err = bt_gatt_exchange_mtu(conn, &exchange_params);
    	if (err) {
    		LOG_WRN("MTU exchange failed (err %d)", err);
    	}
    
    	err = bt_conn_set_security(conn, BT_SECURITY_L2);
    	if (err) {
    		LOG_WRN("Failed to set security: %d", err);
    
    		gatt_discover(conn);
    	}
    
    	err = bt_scan_stop();
    	if ((!err) && (err != -EALREADY)) {
    		LOG_ERR("Stop LE scan failed (err %d)", err);
    	}
    
    	// 启动任务
        k_work_schedule(&rssi_work, K_NO_WAIT);
    }
    
    static void disconnected(struct bt_conn *conn, uint8_t reason)
    {
    	k_work_cancel_delayable(&rssi_work);  // 取消RSSI任务
    
    	char addr[BT_ADDR_LE_STR_LEN];
    	int err;
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_INF("Disconnected: %s, reason 0x%02x %s", addr, reason, bt_hci_err_to_str(reason));
    	
    
    
    	if (default_conn != conn) {
    		return;
    	}
    
    	bt_conn_unref(default_conn);
    	default_conn = NULL;
    
    
    
    	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
    	if (err) {
    		LOG_ERR("Scanning failed to start (err %d)",
    			err);
    	}
    
    }
    
    static void security_changed(struct bt_conn *conn, bt_security_t level,
    			     enum bt_security_err err)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	if (!err) {
    		LOG_INF("Security changed: %s level %u", addr, level);
    	} else {
    		LOG_WRN("Security failed: %s level %u err %d %s", addr, level, err,
    			bt_security_err_to_str(err));
    			
    	}
    
    	gatt_discover(conn);
    }
    
    BT_CONN_CB_DEFINE(conn_callbacks) = {
    	.connected = connected,
    	.disconnected = disconnected,
    	.security_changed = security_changed
    };
    
    static void scan_filter_match(struct bt_scan_device_info *device_info,
    			      struct bt_scan_filter_match *filter_match,
    			      bool connectable)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(device_info->recv_info->addr, addr, sizeof(addr));
    
    	LOG_INF("Filters matched. Address: %s connectable: %d",
    		addr, connectable);
    
    		
    }
    
    static void scan_connecting_error(struct bt_scan_device_info *device_info)
    {
    	LOG_WRN("Connecting failed");
    }
    
    static void scan_connecting(struct bt_scan_device_info *device_info,
    			    struct bt_conn *conn)
    {
    	default_conn = bt_conn_ref(conn);
    }
    
    static int nus_client_init(void)
    {
    	int err;
    	struct bt_nus_client_init_param init = {
    		.cb = {
    			.received = ble_data_received,
    			.sent = ble_data_sent,
    		}
    	};
    
    	err = bt_nus_client_init(&nus_client, &init);
    	if (err) {
    		LOG_ERR("NUS Client initialization failed (err %d)", err);
    		return err;
    	}
    
    	LOG_INF("NUS Client module initialized");
    	return err;
    }
    
    BT_SCAN_CB_INIT(scan_cb, scan_filter_match, NULL,
    		scan_connecting_error, scan_connecting);
    
    static int scan_init(void)
    {
    	int err;
    	struct bt_scan_init_param scan_init = {
    		.connect_if_match = 1,
    	};
    
    	bt_scan_init(&scan_init);
    	bt_scan_cb_register(&scan_cb);
    
    	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_UUID, BT_UUID_NUS_SERVICE);
    	if (err) {
    		LOG_ERR("Scanning filters cannot be set (err %d)", err);
    		return err;
    	}
    
    	err = bt_scan_filter_add(BT_SCAN_FILTER_TYPE_NAME, "Dynamic test beacon"); // 替换为目标设备的名称
        if (err) {
            LOG_ERR("Failed to set name filter (err %d)", err);
            return err;
        }
    
    	err = bt_scan_filter_enable(BT_SCAN_UUID_FILTER|BT_SCAN_NAME_FILTER, false);
    	if (err) {
    		LOG_ERR("Filters cannot be turned on (err %d)", err);
    		return err;
    	}
    
    	LOG_INF("Scan module initialized");
    	return err;
    }
    
    
    static void auth_cancel(struct bt_conn *conn)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_INF("Pairing cancelled: %s", addr);
    }
    
    
    static void pairing_complete(struct bt_conn *conn, bool bonded)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_INF("Pairing completed: %s, bonded: %d", addr, bonded);
    }
    
    
    static void pairing_failed(struct bt_conn *conn, enum bt_security_err reason)
    {
    	char addr[BT_ADDR_LE_STR_LEN];
    
    	bt_addr_le_to_str(bt_conn_get_dst(conn), addr, sizeof(addr));
    
    	LOG_WRN("Pairing failed conn: %s, reason %d %s", addr, reason,
    		bt_security_err_to_str(reason));
    }
    
    static struct bt_conn_auth_cb conn_auth_callbacks = {
    	.cancel = auth_cancel,
    };
    
    static struct bt_conn_auth_info_cb conn_auth_info_callbacks = {
    	.pairing_complete = pairing_complete,
    	.pairing_failed = pairing_failed
    };
    
    int main(void)
    {
    	int err;
    
    	 k_work_init_delayable(&rssi_work, rssi_work_handler);
    
    	err = bt_conn_auth_cb_register(&conn_auth_callbacks);
    	if (err) {
    		LOG_ERR("Failed to register authorization callbacks.");
    		return 0;
    	}
    
    	err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
    	if (err) {
    		printk("Failed to register authorization info callbacks.\n");
    		return 0;
    	}
    
    	err = bt_enable(NULL);
    	if (err) {
    		LOG_ERR("Bluetooth init failed (err %d)", err);
    		return 0;
    	}
    	LOG_INF("Bluetooth initialized");
    
    
    
    	if (IS_ENABLED(CONFIG_SETTINGS)) {
    		settings_load();
    	}
    
    	err = uart_init();
    	if (err != 0) {
    		LOG_ERR("uart_init failed (err %d)", err);
    		return 0;
    	}
    
    	err = scan_init();
    	if (err != 0) {
    		LOG_ERR("scan_init failed (err %d)", err);
    		return 0;
    	}
    
    	err = nus_client_init();
    	if (err != 0) {
    		LOG_ERR("nus_client_init failed (err %d)", err);
    		return 0;
    	}
    
    	printk("Starting Bluetooth Central UART example\n");
    
    	err = bt_scan_start(BT_SCAN_TYPE_SCAN_ACTIVE);
    	if (err) {
    		LOG_ERR("Scanning failed to start (err %d)", err);
    		return 0;
    	}
    
    	LOG_INF("Scanning successfully started");
    
    	struct uart_data_t nus_data = {
    		.len = 0,
    	};
    
    	for (;;) {
    		/* Wait indefinitely for data to be sent over Bluetooth */
    		struct uart_data_t *buf = k_fifo_get(&fifo_uart_rx_data,
    						     K_FOREVER);
    
    		int plen = MIN(sizeof(nus_data.data) - nus_data.len, buf->len);
    		int loc = 0;
    
    		while (plen > 0) {
    			memcpy(&nus_data.data[nus_data.len], &buf->data[loc], plen);
    			nus_data.len += plen;
    			loc += plen;
    			if (nus_data.len >= sizeof(nus_data.data) ||
    			   (nus_data.data[nus_data.len - 1] == '\n') ||
    			   (nus_data.data[nus_data.len - 1] == '\r')) {
    				err = bt_nus_client_send(&nus_client, nus_data.data, nus_data.len);
    				if (err) {
    					LOG_WRN("Failed to send data over BLE connection"
    						"(err %d)", err);
    				}
    
    				err = k_sem_take(&nus_write_sem, NUS_WRITE_TIMEOUT);
    				if (err) {
    					LOG_WRN("NUS send timeout");
    				}
    
    				nus_data.len = 0;
    			}
    
    			plen = MIN(sizeof(nus_data.data), buf->len - loc);
    		}
    
    		k_free(buf);
    	}
    }
    

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