最近收到了Nordic最新的旗艦級(jí)BLE芯片 nRF54L15的開(kāi)發(fā)板，大概研究了一下，今天教大家怎么在上面把BLE跑起來(lái)。

前言：開(kāi)發(fā)板概覽

 1、打開(kāi)包裝之后里面是用防靜電袋包裝的開(kāi)發(fā)板和NFC天線，nRF54L15DK的代號(hào)是PCA10156，但是nRF54L15的開(kāi)發(fā)板對(duì)比nRF52832的開(kāi)發(fā)板來(lái)看，nRF54L15的開(kāi)發(fā)板沒(méi)有再采用Arduion接口將IO引出。開(kāi)發(fā)板上用到的元器件也少了很多，看下來(lái)只用到五顆主芯片。

 開(kāi)發(fā)板的JLINK芯片用的是Nordic的nRF5340，JLINK的USB口換成了Typc-C口。

 電源芯片用上了Nordic自己的PMIC nPM1300

 最后來(lái)看一下nRF54L15部分，這里外掛了一個(gè)MXIC 64Mbit的flash，nRF54L15最小系統(tǒng)的元器件也少了很多。

在網(wǎng)上可以找到nRF54L15的資料：

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

規(guī)格書(shū)：https://docs-be.nordicsemi.com/bundle/ps_nrf54L15/attach/pdf/nRF54L15_nRF54L10_nRF54L05_Datasheet_v0.7.pdf

硬件設(shè)計(jì)：https://www.nordicsemi.com/-/media/Software-and-other-downloads/Reference-Layouts/nRF54L15/nRF54L15-QFAA-Reference-Layout-0_7.zip

 2、環(huán)境搭建

根據(jù)我原廠的朋友的說(shuō)法，新的nRF54L15需要用到NRF Connect SDK去開(kāi)發(fā)，

這里環(huán)境搭建可以參考官方的文檔：Installing the nRF Connect SDK (nordicsemi.com)

最新的文檔已經(jīng)推薦使用nrfutil來(lái)下載SDK了，但是我個(gè)人還是更喜歡用west的方式

這里可以參考中國(guó)區(qū)原廠FAE的博客：開(kāi)發(fā)你的第一個(gè)nRF Connect SDK(NCS)/Zephyr應(yīng)用程序 - iini - 博客園 (cnblogs.com)

按照博客中的方法安裝好Choco和相關(guān)的工具之后，直接執(zhí)行下面兩條命令即可：

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，下載SDK的時(shí)候需要注意。

NRF CONNECT SDK現(xiàn)在的編譯環(huán)境也換成了VS Code + Nordic插件的方式，這里的編譯環(huán)境搭建也可以參考上面中國(guó)區(qū)原廠FAE的博客。

一、在nRF54L15D上運(yùn)行你的第一個(gè)程序

1、搭建好環(huán)境之后，首先我們從SDK中Copy一個(gè)Hello World的工程

2、編譯在NRF54L15DK上運(yùn)行，這里需要注意NCS2.7.x及以上的版本在編譯的時(shí)候需要選擇SysBuild

3、程序編譯之后下載到nRF54L15DK中，打開(kāi)串口我們可以看到串口打印如下：

分別是NCS和Zephyr的版本，以及Hello World!和Boards的型號(hào)

 4、我們打開(kāi)這個(gè)工程的main.c，可以看到這個(gè)工程非常簡(jiǎn)單，就是調(diào)用了printf來(lái)打印Hello World!和CONFIG_BOARD_TARGET這個(gè)宏

二、添加LOG模塊

上面的Hello World使用了printf來(lái)打印，在我們的程序里面可以調(diào)用LOG模塊來(lái)打印調(diào)試日志，這樣方便我們后續(xù)在產(chǎn)品量產(chǎn)的時(shí)候關(guān)閉LOG模塊

1、這里我們先在hello_world/prj.conf中下面這些的宏，開(kāi)啟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中加入下面這些頭文件，調(diào)用LOG的庫(kù)，并注冊(cè)LOG模組

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//Add Log Library file

#include <zephyr.h>

#include <zephyr/logging/log.h>

//Register LOG Module

#define LOG_MODULE_NAME ble_hello_world

LOG_MODULE_REGISTER(LOG_MODULE_NAME);

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3、這里我們提前寫(xiě)一個(gè)bluetooth_init的函數(shù)，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函數(shù)中調(diào)用函數(shù) 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! %s\n", CONFIG_BOARD_TARGET);

}

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5、我們來(lái)編譯并下載程序到nRF54L15DK中會(huì)看到程序進(jìn)入了bluetooth_init 并在串口打印了LOG：

三、使能協(xié)議棧

1、接下來(lái)，我們需要加入BLE相關(guān)的頭文件

//Add BLE Library file

#include <zephyr/bluetooth/bluetooth.h>

#include <zephyr/bluetooth/uuid.h>

#include <zephyr/bluetooth/gatt.h>

#include <zephyr/bluetooth/hci.h>

2、prj.conf中加入這些宏，開(kāi)啟BLE相關(guān)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中調(diào)用bt_enable，這是一個(gè)庫(kù)函數(shù)，這個(gè)函數(shù)的定義的bluetooth.h中，因?yàn)閎t_enable只負(fù)責(zé)調(diào)度BLE協(xié)議棧的啟動(dòng)，而在執(zhí)行其他函數(shù)之前需要確保協(xié)議棧完成了啟動(dòng)，所以我們要做一個(gè)簡(jiǎn)單判斷

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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、我們?nèi)タ匆幌逻@個(gè)函數(shù)的用法，這里看到bt_enable需要一個(gè)回調(diào)函數(shù)

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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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我們?cè)偃タ碽t_ready_cb_t這個(gè)參數(shù)的定義，從這個(gè)注釋中可以得知這個(gè)回調(diào)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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所以為了確保BLE協(xié)議棧已經(jīng)完成了使能，我們需要自己寫(xiě)一個(gè)回調(diào)函數(shù)

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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、這里我們?cè)赽luetooth_init中添加一個(gè)信號(hào)量，等待bt_ready_cb_t通知協(xié)議棧已使能，這里我們調(diào)用K_SEM_DEFINE初始化一個(gè)信號(hào)量，并將其計(jì)數(shù)設(shè)為 1、界限設(shè)為 1，然后在bluetooth_init中調(diào)用k_sem_take()獲取這個(gè)信號(hào)量，因?yàn)槲覀儗⒂?jì)數(shù)設(shè)置為了1，所以程序會(huì)一直在bt_enable()這里等待協(xié)議棧使能完成，當(dāng)然可以將K_FOREVER設(shè)置為一個(gè)時(shí)間，超時(shí)之后程序會(huì)繼續(xù)往下執(zhí)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?yàn)檫@里我們要確保BLE協(xié)議棧使能完成，所以我們可以在bt_ready_callback()中釋放這個(gè)信號(hào)量，這樣我們可以通過(guò)信號(hào)量的同步得知BLE協(xié)議棧已經(jīng)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、最后我們編譯看一下有什么效果，這里可以看到BLE協(xié)議棧已經(jīng)被使能，并打印了版本信息等LOG

 四、開(kāi)啟廣播

使能BLE協(xié)議棧之后，我們接下來(lái)要做的就是開(kāi)啟一個(gè)BLE廣播

1、我們來(lái)設(shè)置廣播包的內(nèi)容，我們可以在廣播包中加入U(xiǎn)UID，這里我們可以寫(xiě)一個(gè)宏來(lái)定義UUID的號(hào)碼

/** @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、我們寫(xiě)一個(gè)宏來(lái)設(shè)置廣播名稱(chēng)，這個(gè)宏最終調(diào)用的是在prj.conf中CONFIG_BT_DEVICE_NAME的值，這里我的定義是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、最后我們把上面的UUID和名稱(chēng)放在廣播包數(shù)據(jù)中，這里我把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、完成廣播數(shù)據(jù)定義之后，我們就可以在bluetooth_init()中調(diào)用bt_le_adv_start()來(lái)開(kāi)啟廣播了。

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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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這里我們可以去看一下bt_le_adv_start()這個(gè)函數(shù)的用法，這是一個(gè)庫(kù)函數(shù)，可以在bluetooth.h中找到聲明，可以看到這個(gè)函數(shù)一共有5個(gè)入?yún)?，分別是

1）const struct bt_le_adv_param *param，是包括廣播周期、廣播類(lèi)型等參數(shù)

2）const struct bt_data *ad, size_t ad_len，分別是廣播包數(shù)據(jù)和廣播包的長(zhǎng)度

3）const struct bt_data *sd, size_t sd_len，分別是掃描響應(yīng)包數(shù)據(jù)和掃描響應(yīng)包的長(zhǎng)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  */

31 int bt_le_adv_start(const struct bt_le_adv_param *param,

32  const struct bt_data *ad, size_t ad_len,

33   const struct bt_data *sd, size_t sd_len);

在上面的代碼中，廣播參數(shù)也調(diào)用了一個(gè)現(xiàn)成的宏，這個(gè)宏在bluetooth.h中可以找到，在這個(gè)宏里面可以看到參數(shù)主義是定義了廣播類(lèi)型為可連接廣播，快速?gòu)V播的最小周期和最大周期。此外廣播包中還定義了一下flag等，感興趣的讀者可以自行去看下面這幾個(gè)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，還有其他好多個(gè)廣播參數(shù)，感興趣的讀者可以去看看其他的宏分別定義了一些什么。

5、最后我們編譯工程來(lái)看一下有什么效果，我們可以使用nRF Connect app去查看一下廣播數(shù)據(jù)

 6、練習(xí)：如果你熟悉nRF5 SDK，你會(huì)發(fā)現(xiàn)在NCS上定義個(gè)廣播參數(shù)和廣播數(shù)據(jù)會(huì)比nRF5 SDK上要簡(jiǎn)單，不需要去寫(xiě)參數(shù)眾多的指針變量，甚至可以直接用現(xiàn)成定義好的宏，許多參數(shù)甚至可以直接在prj.conf中定義即可，這大大減少了代碼開(kāi)發(fā)的工作量。這里感興趣的讀者可以去自行修改Appearance，這個(gè)參數(shù)可以通過(guò)下面這個(gè)宏來(lái)定義，修改這個(gè)宏的值然后在nRF Connect app的廣播設(shè)備的圖標(biāo)會(huì)出現(xiàn)變化，SIG定義了一些標(biāo)準(zhǔn)具體的值，例如心率設(shè)備、HID設(shè)備等，具體去SIG這個(gè)網(wǎng)站查詢：https://www.bluetooth.com/specifications/assigned-numbers

CONFIG_BT_DEVICE_APPEARANCE=0

 

五、BLE的連接回調(diào)

在nRF5 SDK中BLE初始化的時(shí)候會(huì)注冊(cè)一個(gè)回調(diào)函數(shù)ble_evt_handler來(lái)處理BLE連接、斷開(kāi)連接、更新PHY、Timeout等時(shí)候的中斷事件

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/*nRF5 SDK中的BLE中斷事件*/

/**@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，我們也可以這樣來(lái)做，這個(gè)章節(jié)我們將演示如何在連接和斷開(kāi)連接的時(shí)候，打印LOG和點(diǎn)亮\熄滅DK的LED1。

 1、首先我們?cè)赽luetooth_init()加入一個(gè)回調(diào)注冊(cè)函數(shù)bt_conn_cb_register()，這個(gè)函數(shù)在conn.h，我們來(lái)看一下這個(gè)函數(shù)的聲明，可以看到這個(gè)函數(shù)的主要作用就是注冊(cè)一個(gè)callback用來(lái)在連接狀態(tài)下監(jiān)控相關(guān)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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從注釋中我們可以看到這個(gè)函數(shù)需要輸入 struct bt_conn_cb *cb 這個(gè)結(jié)構(gòu)體作為入?yún)?，這個(gè)結(jié)構(gòu)體的聲明也在conn.h中，我們?nèi)タ匆幌逻@個(gè)結(jié)構(gòu)體的注釋?zhuān)梢钥吹竭@個(gè)結(jié)構(gòu)體中給出的相關(guān)BLE回調(diào)函數(shù)是和nRF5 SDK中給出的case是相似的，感興趣的讀者可以自行查看注釋來(lái)進(jìn)一步做對(duì)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、這里我們還是來(lái)演示如何使用CONNECT和DISCONNECT這兩個(gè)回調(diào)來(lái)在BLE斷開(kāi)和連接的時(shí)候處理相關(guān)任務(wù)。首先我們來(lái)寫(xiě)一個(gè)結(jié)構(gòu)體ble_connection_callback ，這個(gè)結(jié)構(gòu)體里面包括兩個(gè)函數(shù)ble_on_connected和ble_on_connected

struct bt_conn_cb ble_connection_callback = {

    .connected    = ble_on_connected,

    .disconnected = ble_on_disconnected,

};

這里我們需要調(diào)用bt_conn_get_dst這個(gè)函數(shù)來(lái)獲取對(duì)端設(shè)備的MAC地址，并調(diào)用bt_addr_le_to_str將獲取到的地址轉(zhuǎn)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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在連接和斷開(kāi)異常的時(shí)候我們還可以調(diào)用bt_hci_err_to_str來(lái)獲取相關(guān)的錯(cuò)誤代碼。

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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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最后調(diào)用dk_set_led_on和dk_set_led_off來(lái)點(diǎn)亮和熄滅nRF54L15 DK的LED1。

3、接下來(lái)我們來(lái)寫(xiě)ble_on_connected和ble_on_connected這兩個(gè)回調(diào)函數(shù)

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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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這里我們引入了一個(gè)全局變量current_conn用于計(jì)數(shù)已連接的設(shè)備數(shù)量，所以需要做一個(gè)聲明

static struct bt_conn *current_conn;

此外我們調(diào)用了LED1這個(gè)外設(shè)用來(lái)指示BLE的連接情況，所以我們還需要在main中初始化LED1這個(gè)外設(shè)，這里我們需要加入一些頭文件并在prj.conf中使能相關(guān)的宏，最后在main中調(diào)用configure_gpio。

//Add LED and Button drivers Library file

#include <dk_buttons_and_leds.h>

# 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、完成上述步驟之后，我們將ble_connection_callback這個(gè)函數(shù)注冊(cè)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! %s\n", CONFIG_BOARD_TARGET);

}

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5、最后我們編譯下載工程到nRF54L15的DK中，使用nRF Connect APP連接可以看到連接和斷開(kāi)之后分別打印了手機(jī)端的MAC地址

 同時(shí)DK的LED1在連接之后常亮

六、添加一個(gè)Service

1、從上面的圖片中可以看到，APP連接nRF54L15 DK之后只有一些通用的Service，這一步我們來(lái)演示如何添加一個(gè)自定義的Service，在nRF5 SDK中我們需要在service_init中初始化給相關(guān)的指針寫(xiě)入值，但在NCS中我們可以直接調(diào)用BT_GATT_SERVICE_DEFINE來(lái)實(shí)現(xiàn)

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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、這里我直接用了NUS服務(wù)的UUID，當(dāng)然你可以自己定義一個(gè)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、最后編譯一下工程下載的nRF54L15DK，并使用nRF Connect APP連接中可以看到多了一個(gè)NUS服務(wù)。

七、添加特征值并定義其屬性

1、完成上述步驟之后，BLE多了一個(gè)Service，但是這個(gè)Service中沒(méi)有Characteristic（特征值），這里我們還可以在BT_GATT_SERVICE_DEFINE中調(diào)用BT_GATT_CHARACTERISTIC，將特征值放在Service下面，這個(gè)結(jié)構(gòu)就像APP上Service下面有特征值那樣，非常直觀。這里我們?nèi)タ匆幌翨T_GATT_CHARACTERISTIC，會(huì)發(fā)現(xiàn)它一共有6個(gè)入?yún)?/div>