从零开始手把手教你写一个基于nRF54L15的BLE工程

最近收到了Nordic最新的旗舰级BLE芯片 nRF54L15的开发板，大概研究了一下，今天教大家怎么在上面把BLE跑起来。

前言：开发板概览

1、打开包装之后里面是用防静电袋包装的开发板和NFC天线，nRF54L15DK的代号是PCA10156，但是nRF54L15的开发板对比nRF52832的开发板来看，nRF54L15的开发板没有再采用Arduion接口将IO引出。开发板上用到的元器件也少了很多，看下来只用到五颗主芯片。

开发板的JLINK芯片用的是Nordic的nRF5340，JLINK的USB口换成了Typc-C口。

电源芯片用上了Nordic自己的PMIC nPM1300

最后来看一下nRF54L15部分，这里外挂了一个MXIC 64Mbit的flash，nRF54L15最小系统的元器件也少了很多。

在网上可以找到nRF54L15的资料：

介绍：https://www.nordicsemi.com/Products/nRF54L15

规格书：https://docs-be.nordicsemi.com/bundle/ps_nrf54L15/attach/pdf/nRF54L15_nRF54L10_nRF54L05_Datasheet_v0.7.pdf

硬件设计：https://www.nordicsemi.com/-/media/Software-and-other-downloads/Reference-Layouts/nRF54L15/nRF54L15-QFAA-Reference-Layout-0_7.zip

2、环境搭建

根据我原厂的朋友的说法，新的nRF54L15需要用到NRF Connect SDK去开发，

这里环境搭建可以参考官方的文档：Installing the nRF Connect SDK (nordicsemi.com)

最新的文档已经推荐使用nrfutil来下载SDK了，但是我个人还是更喜欢用west的方式

这里可以参考中国区原厂FAE的博客：开发你的第一个nRF Connect SDK(NCS)/Zephyr应用程序 - iini - 博客园 (cnblogs.com)

按照博客中的方法安装好Choco和相关的工具之后，直接执行下面两条命令即可：

west init -m https://github.com/nrfconnect/sdk-nrf --mr v2.9.0

west update

nRF54系列的SDK要使用NCS 2.7.0及以上的版本，下载SDK的时候需要注意。

NRF CONNECT SDK现在的编译环境也换成了VS Code + Nordic插件的方式，这里的编译环境搭建也可以参考上面中国区原厂FAE的博客。

一、在nRF54L15D上运行你的第一个程序

1、搭建好环境之后，首先我们从SDK中Copy一个Hello World的工程

2、编译在NRF54L15DK上运行，这里需要注意NCS2.7.x及以上的版本在编译的时候需要选择SysBuild

3、程序编译之后下载到nRF54L15DK中，打开串口我们可以看到串口打印如下：

分别是NCS和Zephyr的版本，以及Hello World!和Boards的型号

4、我们打开这个工程的main.c，可以看到这个工程非常简单，就是调用了printf来打印Hello World!和CONFIG_BOARD_TARGET这个宏

二、添加LOG模块

上面的Hello World使用了printf来打印，在我们的程序里面可以调用LOG模块来打印调试日志，这样方便我们后续在产品量产的时候关闭LOG模块

1、这里我们先在hello_world/prj.conf中下面这些的宏，开启LOG

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#Config logger

CONFIG_LOG=y

CONFIG_USE_SEGGER_RTT=n

CONFIG_LOG_BACKEND_RTT=n

CONFIG_LOG_BACKEND_UART=y

CONFIG_LOG_DEFAULT_LEVEL=3

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2、在main.c中加入下面这些头文件，调用LOG的库，并注册LOG模组

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//Add Log Library file

#include

#include

//Register LOG Module

#define LOG_MODULE_NAME ble_hello_world

LOG_MODULE_REGISTER(LOG_MODULE_NAME);

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3、这里我们提前写一个bluetooth_init的函数，并在bluetooth_init中加入一些LOG信息

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int bluetooth_init(void)

{

int err_code;

LOG_INF("Initiallzing BLE");

err_code = 0;

return err_code;

}

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4、、在main函数中调用函数 bluetooth_init

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int main(void)

{

int err_code;

err_code = bluetooth_init();

if(err_code){

LOG_ERR("Bluetooth_init returnrd %d", err_code)

}

printf("Hello World! %sn", CONFIG_BOARD_TARGET);

}

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5、我们来编译并下载程序到nRF54L15DK中会看到程序进入了bluetooth_init 并在串口打印了LOG：

三、使能协议栈

1、接下来，我们需要加入BLE相关的头文件

//Add BLE Library file

#include

#include

#include

#include

2、prj.conf中加入这些宏，开启BLE相关的宏

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#Config BLE

CONFIG_BT=y

CONFIG_BT_PERIPHERAL=y

CONFIG_BT_DEVICE_NAME="BLE_Hello_World"

CONFIG_BT_DEVICE_APPEARANCE=0

CONFIG_BT_LL_SOFTDEVICE=y

CONFIG_BT_MAX_CONN=1

CONFIG_ASSERT=y

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3、在 bluetooth_init中调用bt_enable，这是一个库函数，这个函数的定义的bluetooth.h中，因为bt_enable只负责调度BLE协议栈的启动，而在执行其他函数之前需要确保协议栈完成了启动，所以我们要做一个简单判断

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int bluetooth_init(void)

{

int err_code;

err_code = bt_enable(bt_ready_callback);

if(err_code)

{

LOG_ERR("BLE Enable returned %d",err_code);

return err_code;

}

LOG_INF("Initiallzing BLE");

return err_code;

}

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3、我们去看一下这个函数的用法，这里看到bt_enable需要一个回调函数

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/**

* @brief Enable Bluetooth

*

* Enable Bluetooth. Must be the called before any calls that

* require communication with the local Bluetooth hardware.

*

* When @kconfig{CONFIG_BT_SETTINGS} is enabled, the application must load the

* Bluetooth settings after this API call successfully completes before

* Bluetooth APIs can be used. Loading the settings before calling this function

* is insufficient. Bluetooth settings can be loaded with settings_load() or

* settings_load_subtree() with argument "bt". The latter selectively loads only

* Bluetooth settings and is recommended if settings_load() has been called

* earlier.

*

* @param cb Callback to notify completion or NULL to perform the

* enabling synchronously. The callback is called from the system workqueue.

*

* @return Zero on success or (negative) error code otherwise.

*/

int bt_enable(bt_ready_cb_t cb);

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我们再去看bt_ready_cb_t这个参数的定义，从这个注释中可以得知这个回调的作用是通知BLE已使能

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/**

* @typedef bt_ready_cb_t

* @brief Callback for notifying that Bluetooth has been enabled.

*

* @param err zero on success or (negative) error code otherwise.

*/

typedef void (*bt_ready_cb_t)(int err);

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所以为了确保BLE协议栈已经完成了使能，我们需要自己写一个回调函数

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/*BLE Enable Callback function*/

void bt_ready_callback(int err_code)

{

if(err_code)

{

LOG_ERR("BLE Enable callback returned %d",err_code);

}

}

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4、这里我们在bluetooth_init中添加一个信号量，等待bt_ready_cb_t通知协议栈已使能，这里我们调用K_SEM_DEFINE初始化一个信号量，并将其计数设为 1、界限设为 1，然后在bluetooth_init中调用k_sem_take()获取这个信号量，因为我们将计数设置为了1，所以程序会一直在bt_enable()这里等待协议栈使能完成，当然可以将K_FOREVER设置为一个时间，超时之后程序会继续往下执行。

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static K_SEM_DEFINE(ble_init_ok, 1, 1);

int bluetooth_init(void)

{

int err_code;

LOG_INF("Initiallzing BLE");

err_code = bt_enable(bt_ready_callback);

if(err_code)

{

LOG_ERR("BLE Enable returned %d",err_code);

return err_code;

}

k_sem_take(&ble_init_ok, K_FOREVER);return err_code;

}

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因为这里我们要确保BLE协议栈使能完成，所以我们可以在bt_ready_callback()中释放这个信号量，这样我们可以通过信号量的同步得知BLE协议栈已经被使能。

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/*BLE Enable Callback function*/

void bt_ready_callback(int err_code)

{

if(err_code)

{

LOG_ERR("BLE Enable callback returned %d",err_code);

}

k_sem_give(&ble_init_ok);

}

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5、最后我们编译看一下有什么效果，这里可以看到BLE协议栈已经被使能，并打印了版本信息等LOG

四、开启广播

使能BLE协议栈之后，我们接下来要做的就是开启一个BLE广播

1、我们来设置广播包的内容，我们可以在广播包中加入UUID，这里我们可以写一个宏来定义UUID的号码

/** @brief UUID of the Hello World Service. **/

#define BT_UUID_HOWD_VAL

BT_UUID_128_ENCODE(0x6e400001, 0xb5a3, 0xf393, 0xe0a9, 0xe50e24dcca9e)

#define BT_UUID_HOWD_SERVICE BT_UUID_DECLARE_128(BT_UUID_HOWD_VAL)

2、我们写一个宏来设置广播名称，这个宏最终调用的是在prj.conf中CONFIG_BT_DEVICE_NAME的值，这里我的定义是CONFIG_BT_DEVICE_NAME="BLE_Hello_World"

/*Config BLE Device Name*/

#define DEVICE_NAME CONFIG_BT_DEVICE_NAME

#define DEVICE_NAME_LEN (sizeof(DEVICE_NAME) - 1)

3、最后我们把上面的UUID和名称放在广播包数据中，这里我把UUID放在了Scan response里面

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/*Config BLE Advertising Data*/

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),

};

/*Config BLE Scan repsponse Data*/

static const struct bt_data srd[] = {

BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_HOWD_VAL),

};

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4、完成广播数据定义之后，我们就可以在bluetooth_init()中调用bt_le_adv_start()来开启广播了。

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int bluetooth_init(void)

{

int err_code;

LOG_INF("Initiallzing BLE");

bt_conn_cb_register();

err_code = bt_enable(bt_ready_callback);

if(err_code)

{

LOG_ERR("BLE Enable returned %d",err_code);

return err_code;

}

k_sem_take(&ble_init_ok, K_FOREVER);

err_code = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), srd,

ARRAY_SIZE(srd));

if (err_code) {

LOG_ERR("Advertising failed to start (err_code %d)", err_code);

return 0;

}

return err_code;

}

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这里我们可以去看一下bt_le_adv_start()这个函数的用法，这是一个库函数，可以在bluetooth.h中找到声明，可以看到这个函数一共有5个入参，分别是

1）const struct bt_le_adv_param *param，是包括广播周期、广播类型等参数

2）const struct bt_data *ad, size_t ad_len，分别是广播包数据和广播包的长度

3）const struct bt_data *sd, size_t sd_len，分别是扫描响应包数据和扫描响应包的长度

1/**

2* @brief Start advertising

3*

4* Set advertisement data, scan response data, advertisement parameters

5* and start advertising.

6*

7* When the advertisement parameter peer address has been set the advertising

8* will be directed to the peer. In this case advertisement data and scan

9* response data parameters are ignored. If the mode is high duty cycle

10* the timeout will be @ref BT_GAP_ADV_HIGH_DUTY_CYCLE_MAX_TIMEOUT.

11*

12* This function cannot be used with @ref BT_LE_ADV_OPT_EXT_ADV in the @p param.options.

13* For extended advertising, the bt_le_ext_adv_* functions must be used.

14*

15* @param param Advertising parameters.

16* @param ad Data to be used in advertisement packets.

17* @param ad_len Number of elements in ad

18* @param sd Data to be used in scan response packets.

19* @param sd_len Number of elements in sd

20*

21* @return Zero on success or (negative) error code otherwise.

22* @return -ENOMEM No free connection objects available for connectable

23* advertiser.

24* @return -ECONNREFUSED When connectable advertising is requested and there

25* is already maximum number of connections established

26* in the controller.

27* This error code is only guaranteed when using Zephyr

28* controller, for other controllers code returned in

29* this case may be -EIO.

30*/

31intbt_le_adv_start(conststructbt_le_adv_param *param,

32conststructbt_data *ad, size_t ad_len,

33 conststructbt_data *sd, size_t sd_len);

在上面的代码中，广播参数也调用了一个现成的宏，这个宏在bluetooth.h中可以找到，在这个宏里面可以看到参数主义是定义了广播类型为可连接广播，快速广播的最小周期和最大周期。此外广播包中还定义了一下flag等，感兴趣的读者可以自行去看下面这几个宏

BT_DATA_BYTES(BT_DATA_FLAGS, (BT_LE_AD_GENERAL | BT_LE_AD_NO_BREDR)

#define BT_LE_ADV_CONN BT_LE_ADV_PARAM(BT_LE_ADV_OPT_CONNECTABLE,

BT_GAP_ADV_FAST_INT_MIN_2,

BT_GAP_ADV_FAST_INT_MAX_2, NULL)

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#define BT_GAP_ADV_FAST_INT_MIN_2 0x00a0 /* 100 ms */

#define BT_GAP_ADV_FAST_INT_MAX_2 0x00f0 /* 150 ms */

/**

* @brief Advertise as connectable.

*

* Advertise as connectable. If not connectable then the type of

* advertising is determined by providing scan response data.

* The advertiser address is determined by the type of advertising

* and/or enabling privacy @kconfig{CONFIG_BT_PRIVACY}.

*/

BT_LE_ADV_OPT_CONNECTABLE = BIT(0),

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此外bluetooth.h中除了BT_LE_ADV_CONN BT_LE_ADV_PARAM之外，还有其他好多个广播参数，感兴趣的读者可以去看看其他的宏分别定义了一些什么。

5、最后我们编译工程来看一下有什么效果，我们可以使用nRF Connect app去查看一下广播数据

6、练习：如果你熟悉nRF5 SDK，你会发现在NCS上定义个广播参数和广播数据会比nRF5 SDK上要简单，不需要去写参数众多的指针变量，甚至可以直接用现成定义好的宏，许多参数甚至可以直接在prj.conf中定义即可，这大大减少了代码开发的工作量。这里感兴趣的读者可以去自行修改Appearance，这个参数可以通过下面这个宏来定义，修改这个宏的值然后在nRF Connect app的广播设备的图标会出现变化，SIG定义了一些标准具体的值，例如心率设备、HID设备等，具体去SIG这个网站查询：https://www.bluetooth.com/specifications/assigned-numbers

CONFIG_BT_DEVICE_APPEARANCE=0

五、BLE的连接回调

在nRF5 SDK中BLE初始化的时候会注册一个回调函数ble_evt_handler来处理BLE连接、断开连接、更新PHY、Timeout等时候的中断事件

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/*nRF5 SDK中的BLE中断事件*/

/**@brief Function for handling BLE events.

*

* @param[in] p_ble_evt Bluetooth stack event.

* @param[in] p_context Unused.

*/

static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)

{

uint32_t err_code;

switch (p_ble_evt->header.evt_id)

{

case BLE_GAP_EVT_CONNECTED:

NRF_LOG_INFO("Connected");

err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);

APP_ERROR_CHECK(err_code);

m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;

err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);

APP_ERROR_CHECK(err_code);

break;

case BLE_GAP_EVT_DISCONNECTED:

NRF_LOG_INFO("Disconnected");

// LED indication will be changed when advertising starts.

m_conn_handle = BLE_CONN_HANDLE_INVALID;

break;

case BLE_GAP_EVT_PHY_UPDATE_REQUEST:

{

NRF_LOG_DEBUG("PHY update request.");

ble_gap_phys_t const phys =

{

.rx_phys = BLE_GAP_PHY_AUTO,

.tx_phys = BLE_GAP_PHY_AUTO,

};

err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);

APP_ERROR_CHECK(err_code);

} break;

case BLE_GAP_EVT_SEC_PARAMS_REQUEST:

// Pairing not supported

err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);

APP_ERROR_CHECK(err_code);

break;

case BLE_GATTS_EVT_SYS_ATTR_MISSING:

// No system attributes have been stored.

err_code = sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0, 0);

APP_ERROR_CHECK(err_code);

break;

case BLE_GATTC_EVT_TIMEOUT:

// Disconnect on GATT Client timeout event.

err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,

BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);

APP_ERROR_CHECK(err_code);

break;

case BLE_GATTS_EVT_TIMEOUT:

// Disconnect on GATT Server timeout event.

err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,

BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);

APP_ERROR_CHECK(err_code);

break;

default:

// No implementation needed.

break;

}

}

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在NCS中，我们也可以这样来做，这个章节我们将演示如何在连接和断开连接的时候，打印LOG和点亮熄灭DK的LED1。

1、首先我们在bluetooth_init()加入一个回调注册函数bt_conn_cb_register()，这个函数在conn.h，我们来看一下这个函数的声明，可以看到这个函数的主要作用就是注册一个callback用来在连接状态下监控相关事件。

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/** @brief Register connection callbacks.

*

* Register callbacks to monitor the state of connections.

*

* @param cb Callback struct. Must point to memory that remains valid.

*

* @retval 0 Success.

* @retval -EEXIST if @p cb was already registered.

*/

int bt_conn_cb_register(struct bt_conn_cb *cb);

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从注释中我们可以看到这个函数需要输入 struct bt_conn_cb *cb 这个结构体作为入参，这个结构体的声明也在conn.h中，我们去看一下这个结构体的注释，可以看到这个结构体中给出的相关BLE回调函数是和nRF5 SDK中给出的case是相似的，感兴趣的读者可以自行查看注释来进一步做对比。

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/** @brief Connection callback structure.

*

* This structure is used for tracking the state of a connection.

* It is registered with the help of the bt_conn_cb_register() API.

* It's permissible to register multiple instances of this @ref bt_conn_cb

* type, in case different modules of an application are interested in

* tracking the connection state. If a callback is not of interest for

* an instance, it may be set to NULL and will as a consequence not be

* used for that instance.

*/

struct bt_conn_cb {

/** @brief A new connection has been established.

*

* This callback notifies the application of a new connection.

* In case the err parameter is non-zero it means that the

* connection establishment failed.

*

* @note If the connection was established from an advertising set then

* the advertising set cannot be restarted directly from this

* callback. Instead use the connected callback of the

* advertising set.

*

* @param conn New connection object.

* @param err HCI error. Zero for success, non-zero otherwise.

*

* @p err can mean either of the following:

* - @ref BT_HCI_ERR_UNKNOWN_CONN_ID Creating the connection started by

* @ref bt_conn_le_create was canceled either by the user through

* @ref bt_conn_disconnect or by the timeout in the host through

* @ref bt_conn_le_create_param timeout parameter, which defaults to

* @kconfig{CONFIG_BT_CREATE_CONN_TIMEOUT} seconds.

* - @p BT_HCI_ERR_ADV_TIMEOUT High duty cycle directed connectable

* advertiser started by @ref bt_le_adv_start failed to be connected

* within the timeout.

*/

void (*connected)(struct bt_conn *conn, uint8_t err);

/** @brief A connection has been disconnected.

*

* This callback notifies the application that a connection

* has been disconnected.

*

* When this callback is called the stack still has one reference to

* the connection object. If the application in this callback tries to

* start either a connectable advertiser or create a new connection

* this might fail because there are no free connection objects

* available.

* To avoid this issue it is recommended to either start connectable

* advertise or create a new connection using @ref k_work_submit or

* increase @kconfig{CONFIG_BT_MAX_CONN}.

*

* @param conn Connection object.

* @param reason BT_HCI_ERR_* reason for the disconnection.

*/

void (*disconnected)(struct bt_conn *conn, uint8_t reason);

/** @brief A connection object has been returned to the pool.

*

* This callback notifies the application that it might be able to

* allocate a connection object. No guarantee, first come, first serve.

*

* Use this to e.g. re-start connectable advertising or scanning.

*

* Treat this callback as an ISR, as it originates from

* @ref bt_conn_unref which is used by the BT stack. Making

* Bluetooth API calls in this context is error-prone and strongly

* discouraged.

*/

void (*recycled)(void);

/** @brief LE connection parameter update request.

*

* This callback notifies the application that a remote device

* is requesting to update the connection parameters. The

* application accepts the parameters by returning true, or

* rejects them by returning false. Before accepting, the

* application may also adjust the parameters to better suit

* its needs.

*

* It is recommended for an application to have just one of these

* callbacks for simplicity. However, if an application registers

* multiple it needs to manage the potentially different

* requirements for each callback. Each callback gets the

* parameters as returned by previous callbacks, i.e. they are not

* necessarily the same ones as the remote originally sent.

*

* If the application does not have this callback then the default

* is to accept the parameters.

*

* @param conn Connection object.

* @param param Proposed connection parameters.

*

* @return true to accept the parameters, or false to reject them.

*/

bool (*le_param_req)(struct bt_conn *conn,

struct bt_le_conn_param *param);

/** @brief The parameters for an LE connection have been updated.

*

* This callback notifies the application that the connection

* parameters for an LE connection have been updated.

*

* @param conn Connection object.

* @param interval Connection interval.

* @param latency Connection latency.

* @param timeout Connection supervision timeout.

*/

void (*le_param_updated)(struct bt_conn *conn, uint16_t interval,

uint16_t latency, uint16_t timeout);

#if defined(CONFIG_BT_SMP)

/** @brief Remote Identity Address has been resolved.

*

* This callback notifies the application that a remote

* Identity Address has been resolved

*

* @param conn Connection object.

* @param rpa Resolvable Private Address.

* @param identity Identity Address.

*/

void (*identity_resolved)(struct bt_conn *conn,

const bt_addr_le_t *rpa,

const bt_addr_le_t *identity);

#endif /* CONFIG_BT_SMP */

#if defined(CONFIG_BT_SMP) || defined(CONFIG_BT_CLASSIC)

/** @brief The security level of a connection has changed.

*

* This callback notifies the application that the security of a

* connection has changed.

*

* The security level of the connection can either have been increased

* or remain unchanged. An increased security level means that the

* pairing procedure has been performed or the bond information from

* a previous connection has been applied. If the security level

* remains unchanged this means that the encryption key has been

* refreshed for the connection.

*

* @param conn Connection object.

* @param level New security level of the connection.

* @param err Security error. Zero for success, non-zero otherwise.

*/

void (*security_changed)(struct bt_conn *conn, bt_security_t level,

enum bt_security_err err);

#endif /* defined(CONFIG_BT_SMP) || defined(CONFIG_BT_CLASSIC) */

#if defined(CONFIG_BT_REMOTE_INFO)

/** @brief Remote information procedures has completed.

*

* This callback notifies the application that the remote information

* has been retrieved from the remote peer.

*

* @param conn Connection object.

* @param remote_info Connection information of remote device.

*/

void (*remote_info_available)(struct bt_conn *conn,

struct bt_conn_remote_info *remote_info);

#endif /* defined(CONFIG_BT_REMOTE_INFO) */

#if defined(CONFIG_BT_USER_PHY_UPDATE)

/** @brief The PHY of the connection has changed.

*

* This callback notifies the application that the PHY of the

* connection has changed.

*

* @param conn Connection object.

* @param info Connection LE PHY information.

*/

void (*le_phy_updated)(struct bt_conn *conn,

struct bt_conn_le_phy_info *param);

#endif /* defined(CONFIG_BT_USER_PHY_UPDATE) */

#if defined(CONFIG_BT_USER_DATA_LEN_UPDATE)

/** @brief The data length parameters of the connection has changed.

*

* This callback notifies the application that the maximum Link Layer

* payload length or transmission time has changed.

*

* @param conn Connection object.

* @param info Connection data length information.

*/

void (*le_data_len_updated)(struct bt_conn *conn,

struct bt_conn_le_data_len_info *info);

#endif /* defined(CONFIG_BT_USER_DATA_LEN_UPDATE) */

#if defined(CONFIG_BT_DF_CONNECTION_CTE_RX)

/** @brief Callback for IQ samples report collected when sampling

* CTE received by data channel PDU.

*

* @param conn The connection object.

* @param iq_report Report data for collected IQ samples.

*/

void (*cte_report_cb)(struct bt_conn *conn,

const struct bt_df_conn_iq_samples_report *iq_report);

#endif /* CONFIG_BT_DF_CONNECTION_CTE_RX */

#if defined(CONFIG_BT_TRANSMIT_POWER_CONTROL)

/** @brief LE Read Remote Transmit Power Level procedure has completed or LE

* Transmit Power Reporting event.

*

* This callback notifies the application that either the remote transmit power level

* has been read from the peer or transmit power level has changed for the local or

* remote controller when transmit power reporting is enabled for the respective side

* using @ref bt_conn_le_set_tx_power_report_enable.

*

* @param conn Connection object.

* @param report Transmit power report.

*/

void (*tx_power_report)(struct bt_conn *conn,

const struct bt_conn_le_tx_power_report *report);

#endif /* CONFIG_BT_TRANSMIT_POWER_CONTROL */

#if defined(CONFIG_BT_PATH_LOSS_MONITORING)

/** @brief LE Path Loss Threshold event.

*

* This callback notifies the application that there has been a path loss threshold

* crossing or reporting the initial path loss threshold zone after using

* @ref bt_conn_le_set_path_loss_mon_enable.

*

* @param conn Connection object.

* @param report Path loss threshold report.

*/

void (*path_loss_threshold_report)(struct bt_conn *conn,

const struct bt_conn_le_path_loss_threshold_report *report);

#endif /* CONFIG_BT_PATH_LOSS_MONITORING */

#if defined(CONFIG_BT_SUBRATING)

/** @brief LE Subrate Changed event.

*

* This callback notifies the application that the subrating parameters

* of the connection may have changed.

* The connection subrating parameters will be unchanged

* if status is not BT_HCI_ERR_SUCCESS.

*

* @param conn Connection object.

* @param params New subrating parameters.

*/

void (*subrate_changed)(struct bt_conn *conn,

const struct bt_conn_le_subrate_changed *params);

#endif /* CONFIG_BT_SUBRATING */

#if defined(CONFIG_BT_CHANNEL_SOUNDING)

/** @brief LE CS Read Remote Supported Capabilities Complete event.

*

* This callback notifies the application that the remote channel

* sounding capabilities have been received from the peer.

*

* @param conn Connection object.

* @param remote_cs_capabilities Remote Channel Sounding Capabilities.

*/

void (*le_cs_remote_capabilities_available)(struct bt_conn *conn,

struct bt_conn_le_cs_capabilities *params);

/** @brief LE CS Read Remote FAE Table Complete event.

*

* This callback notifies the application that the remote mode-0

* FAE Table has been received from the peer.

*

* @param conn Connection object.

* @param params FAE Table.

*/

void (*le_cs_remote_fae_table_available)(struct bt_conn *conn,

struct bt_conn_le_cs_fae_table *params);

/** @brief LE CS Config created.

*

* This callback notifies the application that a Channel Sounding

* Configuration procedure has completed and a new CS config is created

*

* @param conn Connection object.

* @param config CS configuration.

*/

void (*le_cs_config_created)(struct bt_conn *conn, struct bt_conn_le_cs_config *config);

/** @brief LE CS Config removed.

*

* This callback notifies the application that a Channel Sounding

* Configuration procedure has completed and a CS config is removed

*

* @param conn Connection object.

* @param config_id ID of the CS configuration that was removed.

*/

void (*le_cs_config_removed)(struct bt_conn *conn, uint8_t config_id);

/** @brief Subevent Results from a CS procedure are available.

*

* This callback notifies the user that CS subevent results are

* available for the given connection object.

*

* @param conn Connection objects.

* @param result Subevent results

*/

void (*le_cs_subevent_data_available)(struct bt_conn *conn,

struct bt_conn_le_cs_subevent_result *result);

/** @brief LE CS Security Enabled.

*

* This callback notifies the application that a Channel Sounding

* Security Enable procedure has completed

*

* @param conn Connection object.

*/

void (*le_cs_security_enabled)(struct bt_conn *conn);

/** @brief LE CS Procedure Enabled.

*

* This callback notifies the application that a Channel Sounding

* Procedure Enable procedure has completed

*

* @param conn Connection object.

* @param params CS Procedure Enable parameters

*/

void (*le_cs_procedure_enabled)(

struct bt_conn *conn, struct bt_conn_le_cs_procedure_enable_complete *params);

#endif

/** @internal Internally used field for list handling */

sys_snode_t _node;

};

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2、这里我们还是来演示如何使用CONNECT和DISCONNECT这两个回调来在BLE断开和连接的时候处理相关任务。首先我们来写一个结构体ble_connection_callback ，这个结构体里面包括两个函数ble_on_connected和ble_on_connected

struct bt_conn_cb ble_connection_callback = {

.connected = ble_on_connected,

.disconnected = ble_on_disconnected,

};

这里我们需要调用bt_conn_get_dst这个函数来获取对端设备的MAC地址，并调用bt_addr_le_to_str将获取到的地址转成字符串用于打印。

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/** @brief Get destination (peer) address of a connection.

*

* @param conn Connection object.

*

* @return Destination address.

*/

const bt_addr_le_t *bt_conn_get_dst(const struct bt_conn *conn);

/** @brief Converts binary LE Bluetooth address to string.

*

* @param addr Address of buffer containing binary LE Bluetooth address.

* @param str Address of user buffer with enough room to store

* formatted string containing binary LE address.

* @param len Length of data to be copied to user string buffer. Refer to

* BT_ADDR_LE_STR_LEN about recommended value.

*

* @return Number of successfully formatted bytes from binary address.

*/

static inline int bt_addr_le_to_str(const bt_addr_le_t *addr, char *str,

size_t len)

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在连接和断开异常的时候我们还可以调用bt_hci_err_to_str来获取相关的错误代码。

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/** Converts a HCI error to string.

*

* The error codes are described in the Bluetooth Core specification,

* Vol 1, Part F, Section 2.

*

* The HCI documentation found in Vol 4, Part E,

* describes when the different error codes are used.

*

* See also the defined BT_HCI_ERR_* macros.

*

* @return The string representation of the HCI error code.

* If @kconfig{CONFIG_BT_HCI_ERR_TO_STR} is not enabled,

* this just returns the empty string

*/

#if defined(CONFIG_BT_HCI_ERR_TO_STR)

const char *bt_hci_err_to_str(uint8_t hci_err);

#else

static inline const char *bt_hci_err_to_str(uint8_t hci_err)

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最后调用dk_set_led_on和dk_set_led_off来点亮和熄灭nRF54L15 DK的LED1。

3、接下来我们来写ble_on_connected和ble_on_connected这两个回调函数

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static void ble_on_connected(struct bt_conn *conn, uint8_t err)

{

char addr[BT_ADDR_LE_STR_LEN];

/*Print err code when the connection is error*/

if (err) {

LOG_ERR("Connection failed, err 0x%02x %s", err, bt_hci_err_to_str(err));

return;

}

/*Print the MAC address of Central Deevice*/

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

LOG_INF("Connected %s", addr);

/*Count the coennection*/

current_conn = bt_conn_ref(conn);

dk_set_led_on(DK_LED1)

);

}

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static void ble_on_disconnected(struct bt_conn *conn, uint8_t reason)

{

char addr[BT_ADDR_LE_STR_LEN];

/*Get the MAC address of central and print it when the connection is disconnected*/

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));

/*Decrement a connection's reference count and off LED1 of DK*/

if (current_conn) {

bt_conn_unref(current_conn);

current_conn = NULL;

dk_set_led_off(DK_LED1);

}

}

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这里我们引入了一个全局变量current_conn用于计数已连接的设备数量，所以需要做一个声明

static struct bt_conn *current_conn;

此外我们调用了LED1这个外设用来指示BLE的连接情况，所以我们还需要在main中初始化LED1这个外设，这里我们需要加入一些头文件并在prj.conf中使能相关的宏，最后在main中调用configure_gpio。

//Add LED and Button drivers Library file

#include

# Enable DK LED and Buttons library

CONFIG_DK_LIBRARY=y

CONFIG_GPIO=y

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static void configure_gpio(void)

{

int err_code;

err_code = dk_leds_init();

if (err_code) {

LOG_ERR("Cannot init LEDs (err: %d)", err_code);

}

}

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4、完成上述步骤之后，我们将ble_connection_callback这个函数注册到bluetooth_init中

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int bluetooth_init(struct bt_conn_cb *ble_cb)

{

int err_code;

LOG_INF("Initiallzing BLE");

if (ble_cb == NULL)

{

return -NRFX_ERROR_NULL;

}

bt_conn_cb_register(ble_cb);

err_code = bt_enable(bt_ready_callback);

if(err_code)

{

LOG_ERR("BLE Enable returned %d",err_code);

return err_code;

}

k_sem_take(&ble_init_ok, K_FOREVER);

err_code = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), srd,

ARRAY_SIZE(srd));

if (err_code) {

LOG_ERR("Advertising failed to start (err_code %d)", err_code);

return 0;

}

return err_code;

}

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int main(void)

{

int err_code;

configure_gpio();

err_code = bluetooth_init(&ble_connection_callback);

if(err_code)

{

LOG_ERR("Bluetooth_init returnrd %d", err_code);

}

printf("Hello World! %sn", CONFIG_BOARD_TARGET);

}

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5、最后我们编译下载工程到nRF54L15的DK中，使用nRF Connect APP连接可以看到连接和断开之后分别打印了手机端的MAC地址

同时DK的LED1在连接之后常亮

六、添加一个Service

1、从上面的图片中可以看到，APP连接nRF54L15 DK之后只有一些通用的Service，这一步我们来演示如何添加一个自定义的Service，在nRF5 SDK中我们需要在service_init中初始化给相关的指针写入值，但在NCS中我们可以直接调用BT_GATT_SERVICE_DEFINE来实现

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/**

* @brief Statically define and register a service.

*

* Helper macro to statically define and register a service.

*

* @param _name Service name.

*/

#define BT_GATT_SERVICE_DEFINE(_name, ...)

const struct bt_gatt_attr attr_##_name[] = { __VA_ARGS__ };

const STRUCT_SECTION_ITERABLE(bt_gatt_service_static, _name) =

BT_GATT_SERVICE(attr_##_name)

#define _BT_GATT_ATTRS_ARRAY_DEFINE(n, _instances, _attrs_def)

static struct bt_gatt_attr attrs_##n[] = _attrs_def(_instances[n])

#define _BT_GATT_SERVICE_ARRAY_ITEM(_n, _) BT_GATT_SERVICE(attrs_##_n)

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2、这里我直接用了NUS服务的UUID，当然你可以自己定义一个UUID看一下有什么效果

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/** @brief UUID of the NUS Service. **/

#define BT_UUID_HOWD_VAL

BT_UUID_128_ENCODE(0x6e400001, 0xb5a3, 0xf393, 0xe0a9, 0xe50e24dcca9e)

#define BT_UUID_HOWD_SERVICE BT_UUID_DECLARE_128(BT_UUID_HOWD_VAL)

#define SERVICE_NAME nus_svc

BT_GATT_SERVICE_DEFINE(SERVICE_NAME,

BT_GATT_PRIMARY_SERVICE(BT_UUID_HOWD_SERVICE)

);

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3、最后编译一下工程下载的nRF54L15DK，并使用nRF Connect APP连接中可以看到多了一个NUS服务。

七、添加特征值并定义其属性

1、完成上述步骤之后，BLE多了一个Service，但是这个Service中没有Characteristic（特征值），这里我们还可以在BT_GATT_SERVICE_DEFINE中调用BT_GATT_CHARACTERISTIC，将特征值放在Service下面，这个结构就像APP上Service下面有特征值那样，非常直观。这里我们去看一下BT_GATT_CHARACTERISTIC，会发现它一共有6个入参

1）_uuid是特征值的UUID

2）_props是特征值的属性，比如：read，write，Notify，indicate等

3）_perm是属性的访问权限，比如：普通、加密、配对等

4）_read、_write是分别是读取和写入的回调函数

5）_user_data是留给用户自定义的一些数据，一般不用

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/**

* @brief Characteristic and Value Declaration Macro.

*

* Helper macro to declare a characteristic attribute along with its

* attribute value.

*

* @param _uuid Characteristic attribute uuid.

* @param _props Characteristic attribute properties,

* a bitmap of ``BT_GATT_CHRC_*`` macros.

* @param _perm Characteristic Attribute access permissions,

* a bitmap of @ref bt_gatt_perm values.

* @param _read Characteristic Attribute read callback

* (@ref bt_gatt_attr_read_func_t).

* @param _write Characteristic Attribute write callback

* (@ref bt_gatt_attr_write_func_t).

* @param _user_data Characteristic Attribute user data.

*/

#define BT_GATT_CHARACTERISTIC(_uuid, _props, _perm, _read, _write, _user_data)

BT_GATT_ATTRIBUTE(BT_UUID_GATT_CHRC, BT_GATT_PERM_READ,

bt_gatt_attr_read_chrc, NULL,

((struct bt_gatt_chrc[]) {

BT_GATT_CHRC_INIT(_uuid, 0U, _props),

})),

BT_GATT_ATTRIBUTE(_uuid, _perm, _read, _write, _user_data)

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2、这里因为我们这个特征值的属性是Read，所以我们需要在写一个回调，在里面将Button的键值通过GATT接口发送出去，这需要用到一个库函数bt_gatt_attr_read，这个函数的声明在gatt.h中，可以看到这个函数的作用是将本地数据通过Read属性上传

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/** @brief Generic Read Attribute value helper.

*

* Read attribute value from local database storing the result into buffer.

*

* @param conn Connection object.

* @param attr Attribute to read.

* @param buf Buffer to store the value.

* @param buf_len Buffer length.

* @param offset Start offset.

* @param value Attribute value.

* @param value_len Length of the attribute value.

*

* @return number of bytes read in case of success or negative values in

* case of error.

*/

ssize_t bt_gatt_attr_read(struct bt_conn *conn, const struct bt_gatt_attr *attr,

void *buf, uint16_t buf_len, uint16_t offset,

const void *value, uint16_t value_len);

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3、我们来尝试加一个Read属性的特征值，读取按键DK上按下的Button的键值，从BT_GATT_CHARACTERISTIC的注释中可以看到，要使用这个宏需要写一个回调函数，首先来声明以下这个回调函数，并将bt_gatt_attr_read的入参作为回调函数的入参

ssize_t read_button_characteristic_cb(struct bt_conn *conn, const struct bt_gatt_attr *attr,

void *buf, uint16_t len, uint16_t offset);

这个函数的实际功能是在Read这个特征值的时候，将键值上传给GATT，所以我们来定义一个全局变量来获取button的键值

static uint8_t button_value = 0;

然后将button_value通过bt_gatt_attr_read上传给GATT

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ssize_t read_button_characteristic_cb(struct bt_conn *conn, const struct bt_gatt_attr *attr,

void *buf, uint16_t len, uint16_t offset)

{

return bt_gatt_attr_read(conn, attr, buf, len, offset, &button_value, sizeof(button_value));

}

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4、将这个回调放入BT_GATT_CHARACTERISTIC中，并写入这个Read特征值的属性等相关配置。

这里的特征值的UUID我用了NUS服务TX的特征值；

BT_GATT_CHRC_READ表示特征值的属性是Read

BT_GATT_PERM_READ表示特征值的访问权限为普通读取

读取的回调使用我们写好的read_button_characteristic_cb这个函数

因为这个特征值只是Read属性，所以不需要Write的回调，也不需要用户自定义数据，所以最后两个入参填写为NULL

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#define BT_UUID_NUS_TX_VAL

BT_UUID_128_ENCODE(0x6e400003, 0xb5a3, 0xf393, 0xe0a9, 0xe50e24dcca9e)

#define BT_UUID_NUS_TX BT_UUID_DECLARE_128(BT_UUID_NUS_TX_VAL)

BT_GATT_SERVICE_DEFINE(SERVICE_NAME,

BT_GATT_PRIMARY_SERVICE(BT_UUID_NUS_SERVICE),

BT_GATT_CHARACTERISTIC(BT_UUID_NUS_TX,

BT_GATT_CHRC_READ,

BT_GATT_PERM_READ,

read_button_characteristic_cb, NULL, NULL),

);

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GATT的属性和权限除了上述两个参数之外，还有其他类型，感兴趣的读者具体可以去gatt.h中查看相关注释说明。

5、至此我们已经完成了BLE数据上传部分的代码编写，接下来我们来读取Button的键值，并将这个值给到全局变量button_value即可。这里我们写一个函数来传递button的键值

void set_button_value(uint8_t btn_value)

{

button_value = btn_value;

}

我们还需要通过GPIO外设来读取键值，和点亮LED一样，需要先将DK的Button初始化，这里要调用dk_buttons_init来完成，它是一个库函数，函数声明在dk_buttons_and_leds.h中。

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/** @brief Initialize the library to read the button state.

*

* @param button_handler Callback handler for button state changes.

*

* @retval 0 If the operation was successful.

* Otherwise, a (negative) error code is returned.

*/

int dk_buttons_init(button_handler_t button_handler);

/**

* @typedef button_handler_t

* @brief Callback that is executed when a button state change is detected.

*

* @param button_state Bitmask of button states.

* @param has_changed Bitmask that shows which buttons have changed.

*/

typedef void (*button_handler_t)(uint32_t button_state, uint32_t has_changed);

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从注释可以看到这个函数需要一个button的回调函数，用于处理button时候的中断。我们来写这个回调，在里面处理不同按键按下之后，定义不同的键值，并通过LOG打印键值，最后调用set_button_value将键值传递给全局变量button_value。

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void button_handler(uint32_t button_state, uint32_t has_changed)

{

int button_pressed = 0;

if (has_changed & button_state) {

if (DK_BTN1_MSK & has_changed) {

button_pressed = 1;

}

if (DK_BTN2_MSK & has_changed) {

button_pressed = 2;

}

if (DK_BTN3_MSK & has_changed) {

button_pressed = 3;

}

if (DK_BTN4_MSK & has_changed) {

button_pressed = 4;

}

LOG_INF("Button %d pressed", button_pressed);

set_button_value(button_pressed);

}

}

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最后在GPIO初始化里面调用dk_buttons_init并写入回调函数button_handler即可。

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static void configure_gpio(void)

{

int err_code;

err_code = dk_buttons_init(button_handler);

if (err_code) {

LOG_ERR("Cannot init buttons (err: %d)", err_code);

}

err_code = dk_leds_init();

if (err_code) {

LOG_ERR("Cannot init LEDs (err: %d)", err_code);

}

}

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6、最后编译工程，并使用nRF Connect APP连接nRF54L15DK的广播，可以看到NUS Service下多了一个Read属性，当我们按下DK上的Button的时候，可以读取到对应的键值。

持续未完........

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