static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context) { uint16_t conn_handle = p_ble_evt->evt.gap_evt.conn_handle; uint16_t role = ble_conn_state_role(conn_handle); #if __USER_1_DEBUG__ test_printf("role = %d\r\n", role); #endif // Based on the role this device plays in the connection, dispatch to the right handler. if (role == BLE_GAP_ROLE_PERIPH || ble_evt_is_advertising_timeout(p_ble_evt)) { ble_evt_dispatch(p_ble_evt, p_context); } else if ((role == BLE_GAP_ROLE_CENTRAL) || (p_ble_evt->header.evt_id == BLE_GAP_EVT_ADV_REPORT)) { ble_module_central_evt(p_ble_evt, p_context); } }

这段代码实现了一个 BLE 事件处理函数，当发生 BLE 事件时，该函数会被调用。函数首先通过连接句柄获取 BLE 设备的角色（是从设备还是主设备），然后根据角色类型分发事件到不同的事件处理函数中。

如果该设备是从设备（BLE_GAP_ROLE_PERIPH），或者广播超时（ble_evt_is_advertising_timeout(p_ble_evt)），则直接调用 ble_evt_dispatch() 函数处理该事件。

如果该设备是主设备（BLE_GAP_ROLE_CENTRAL），或者事件 ID 是 BLE_GAP_EVT_ADV_REPORT，则调用 ble_module_central_evt() 函数处理该事件。

其中，p_ble_evt 是一个 BLE 事件结构体指针，包含了 BLE 事件的各种信息，而 p_context 则是一个用户定义的上下文指针，可以用来传递一些额外的参数或数据。

相关问题

nordic函数库里面的sd_ble_gattc_read()函数的参数，并给出实际调用例子

nordic函数库里面的sd_ble_gattc_read()函数的参数如下：

uint32_t sd_ble_gattc_read(uint16_t conn_handle, uint16_t handle, uint16_t offset, uint8_t *p_data, uint16_t *p_len, uint8_t options);

其中，参数的含义和作用如下：

- `conn_handle`：连接句柄，表示要读取哪一个连接上的属性值。
- `handle`：属性句柄，表示要读取哪一个属性的值。
- `offset`：偏移量，表示从属性值的哪一个位置开始读取数据。
- `p_data`：数据指针，用于存储读取到的属性值数据。
- `p_len`：数据长度指针，用于存储读取到的属性值数据的长度。
- `options`：选项，用于控制读取操作的行为，例如是否使用长特征值读取等。

下面是一个实际调用例子：

#include "ble_gattc.h"

// 定义回调函数
void gattc_read_response_handler(ble_gattc_evt_t const *p_evt)
{
    // 处理读取结果
}

// 在合适的地方调用 sd_ble_gattc_read 函数
uint16_t handle = 0x0002; // 要读取的属性句柄
uint8_t data[20]; // 存储读取结果的缓冲区
uint16_t len = 0; // 存储读取结果的长度
uint16_t conn_handle = 0x0001; // 连接句柄
uint8_t options = 0; // 读取选项

ret_code_t err_code = sd_ble_gattc_read(conn_handle, handle, 0, data, &len, options);
if (err_code != NRF_SUCCESS) {
    // 处理错误
}

// 注册回调函数
err_code = sd_ble_gattc_register_handles_read_response(gattc_read_response_handler);
if (err_code != NRF_SUCCESS) {
    // 处理错误
}

在上述代码中，我们首先定义了一个回调函数 `gattc_read_response_handler`，用于处理读取操作完成后的结果。然后在合适的地方调用 `sd_ble_gattc_read` 函数，传入要读取的属性句柄、缓冲区、连接句柄和选项等参数。最后，我们还注册了回调函数，以便在读取操作完成后能够及时处理结果。

esp32 蓝牙启动流程_ESP32教你简单进行蓝牙串口调试

ESP32的蓝牙启动流程如下：

1. 初始化蓝牙协议栈

2. 配置蓝牙参数，如设备名称、服务UUID等

3. 注册蓝牙事件回调函数

4. 启动蓝牙广播

5. 开启蓝牙可见性

6. 等待连接

以下是一个简单的ESP32蓝牙串口调试的示例：

#include "esp_bt.h"
#include "esp_bt_main.h"
#include "esp_gap_ble_api.h"

#define GATTS_TAG "GATTS_DEMO"
#define TEST_DEVICE_NAME "ESP32_BLE_UART"
#define TEST_MANUFACTURER_DATA_LEN 17

/* The max length of characteristic value. When the gatt client write or prepare write,
*  the data length must be less than MAX_VALUE_LENGTH.
*/
#define MAX_VALUE_LENGTH 500

/* Declare global variable */
static uint8_t test_manufacturer[TEST_MANUFACTURER_DATA_LEN] = {0x4c, 0x00, 0x02, 0x15, 0xE2, 0x0A, 0x39, 0xF4, 0x73, 0xF5, 0x4B, 0xC4, 0xA1, 0x2F, 0x17, 0xD1, 0xAD};
static uint8_t test_service_uuid128[32] = {
    /* LSB <--------------------------------------------------------------------------------> MSB */
    //first uuid, 16bit, [12],[13] is the value
    0x13, 0x2B, 0x01, 0x00, 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB,
    //second uuid, 32bit, [12], [13], [14], [15] is the value
    0x14, 0x2B, 0x01, 0x00, 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB,
};

static uint8_t test_service_uuid[16] = {
    /* LSB <--------------------------------------------------------------------------------> MSB */
    //first uuid, 16bit, [12],[13] is the value
    0x01, 0x2B,
    //second uuid, 32bit, [12], [13], [14], [15] is the value
    0x01, 0x2B, 0x01, 0x00, 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB,
};

static uint8_t test_char_uuid[16] = {
    /* LSB <--------------------------------------------------------------------------------> MSB */
    //first uuid, 16bit, [12],[13] is the value
    0x02, 0x2B,
    //second uuid, 32bit, [12], [13], [14], [15] is the value
    0x02, 0x2B, 0x01, 0x00, 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0x80, 0x5F, 0x9B, 0x34, 0xFB,
};

static esp_gatt_char_prop_t test_property = 0;

static uint8_t char1_str[] = {0x11,0x22,0x33};
static esp_attr_value_t gatts_demo_char1_val = {
    .attr_max_len = MAX_VALUE_LENGTH,
    .attr_len     = sizeof(char1_str),
    .attr_value   = char1_str,
};

static uint16_t gatts_demo_handle_table[3];

/* Full Database Description - Used to add attributes into the database */
static const esp_gatts_attr_db_t gatt_db[HRS_IDX_NB] =
{
    // Service Declaration
    [IDX_SVC]        =
    {
        {ESP_GATT_AUTO_RSP},
        {ESP_UUID_LEN_16, (uint8_t *)&primary_service_uuid, ESP_GATT_PERM_READ,
            sizeof(test_service_uuid), sizeof(test_service_uuid), (uint8_t *)&test_service_uuid},
        ESP_GATT_UUID_PRI_SERVICE,
        ESP_GATT_PERM_READ,
        sizeof(test_service_uuid),
        sizeof(test_service_uuid),
        (uint8_t *)&test_service_uuid,
        0
    },
    /* Characteristic Declaration */
    [IDX_CHAR_READ]  =
    {
        {ESP_GATT_AUTO_RSP},
        {ESP_UUID_LEN_16, (uint8_t *)&character_declaration_uuid, ESP_GATT_PERM_READ,
            CHAR_DECLARATION_SIZE, CHAR_DECLARATION_SIZE, (uint8_t *)&test_property},
        ESP_GATT_UUID_CHAR_DECLARE,
        ESP_GATT_PERM_READ,
        CHAR_DECLARATION_SIZE,
        CHAR_DECLARATION_SIZE,
        (uint8_t *)&test_property,
        0
    },
    /* Characteristic Value */
    [IDX_CHAR_VAL_READ] =
    {
        {ESP_GATT_AUTO_RSP},
        {ESP_UUID_LEN_128, (uint8_t *)&test_char_uuid, ESP_GATT_PERM_READ,
            MAX_VALUE_LENGTH, sizeof(gatts_demo_char1_val), gatts_demo_char1_val.attr_value},
        ESP_UUID_LEN_128,
        ESP_GATT_PERM_READ,
        MAX_VALUE_LENGTH,
        sizeof(gatts_demo_char1_val),
        gatts_demo_char1_val.attr_value,
        0
    },
};

static esp_ble_adv_data_t adv_data = {
    .set_scan_rsp        = false,
    .include_name        = true,
    .include_txpower     = true,
    .min_interval        = 0x20,
    .max_interval        = 0x40,
    .appearance          = 0x00,
    .manufacturer_len    = TEST_MANUFACTURER_DATA_LEN,
    .p_manufacturer_data = test_manufacturer,
    .service_data_len    = 0,
    .p_service_data      = NULL,
    .service_uuid_len    = sizeof(test_service_uuid),
    .p_service_uuid      = test_service_uuid,
    .flag = (ESP_BLE_ADV_FLAG_GEN_DISC | ESP_BLE_ADV_FLAG_BREDR_NOT_SPT),
};

static esp_ble_adv_params_t adv_params = {
    .adv_int_min         = 0x20,
    .adv_int_max         = 0x40,
    .adv_type            = ADV_TYPE_IND,
    .own_addr_type       = BLE_ADDR_TYPE_PUBLIC,
    .peer_addr           = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
    .peer_addr_type      = BLE_ADDR_TYPE_PUBLIC,
    .channel_map         = ADV_CHNL_ALL,
    .adv_filter_policy   = ADV_FILTER_ALLOW_SCAN_ANY_CON_ANY,
};

static void gap_event_handler(esp_gap_ble_cb_event_t event, esp_ble_gap_cb_param_t *param)
{
    switch (event) {
    case ESP_GAP_BLE_ADV_DATA_SET_COMPLETE_EVT:
        esp_ble_gap_start_advertising(&adv_params);
        break;
    case ESP_GAP_BLE_ADV_START_COMPLETE_EVT:
        if (param->adv_start_cmpl.status != ESP_BT_STATUS_SUCCESS) {
            ESP_LOGE(GATTS_TAG, "advertising start failed");
        }
        break;
    default:
        break;
    }
}

static void gatts_event_handler(esp_gatts_cb_event_t event, esp_gatt_if_t gatts_if, esp_ble_gatts_cb_param_t *param)
{
    switch (event) {
    case ESP_GATTS_REG_EVT:
        esp_ble_gap_set_device_name(TEST_DEVICE_NAME);
        esp_ble_gap_config_adv_data(&adv_data);
        break;
    case ESP_GATTS_CREAT_ATTR_TAB_EVT:
        if (param->add_attr_tab.status != ESP_GATT_OK){
            ESP_LOGE(GATTS_TAG, "create attribute table failed, error code=0x%x", param->add_attr_tab.status);
        }
        else if (param->add_attr_tab.num_handle != HRS_IDX_NB) {
            ESP_LOGE(GATTS_TAG, "create attribute table abnormally, num_handle (%d) \
                    doesn't equal to HRS_IDX_NB(%d)", param->add_attr_tab.num_handle, HRS_IDX_NB);
        }
        else {
            ESP_LOGI(GATTS_TAG, "create attribute table successfully, the number handle = %d\n",param->add_attr_tab.num_handle);
            memcpy(gatts_demo_handle_table, param->add_attr_tab.handles, sizeof(gatts_demo_handle_table));
            esp_ble_gatts_start_service(gatts_demo_handle_table[IDX_SVC]);
        }
        break;
    case ESP_GATTS_CONNECT_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CONNECT_EVT");
        break;
    case ESP_GATTS_DISCONNECT_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_DISCONNECT_EVT");
        esp_ble_gap_start_advertising(&adv_params);
        break;
    case ESP_GATTS_WRITE_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_WRITE_EVT");
        break;
    case ESP_GATTS_MTU_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_MTU_EVT, MTU %d", param->mtu.mtu);
        break;
    case ESP_GATTS_CONF_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CONF_EVT");
        break;
    case ESP_GATTS_EXEC_WRITE_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_EXEC_WRITE_EVT");
        break;
    case ESP_GATTS_START_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_START_EVT");
        break;
    case ESP_GATTS_STOP_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_STOP_EVT");
        break;
    case ESP_GATTS_OPEN_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_OPEN_EVT");
        break;
    case ESP_GATTS_CANCEL_OPEN_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CANCEL_OPEN_EVT");
        break;
    case ESP_GATTS_CLOSE_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CLOSE_EVT");
        break;
    case ESP_GATTS_LISTEN_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_LISTEN_EVT");
        break;
    case ESP_GATTS_CONGEST_EVT:
        ESP_LOGI(GATTS_TAG, "ESP_GATTS_CONGEST_EVT");
        break;
    case ESP_GATTS_UNREG_EVT:
    case ESP_GATTS_DELETE_EVT:
    default:
        break;
    }
}

void app_main()
{
    esp_err_t ret;

    ESP_LOGI(GATTS_TAG, "ESP_BLUETOOTH_BLE example started.");

    esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
    ret = esp_bt_controller_init(&bt_cfg);
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s initialize controller failed\n", __func__);
        return;
    }

    ret = esp_bt_controller_enable(ESP_BT_MODE_BLE);
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s enable controller failed\n", __func__);
        return;
    }

    ret = esp_bluedroid_init();
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s init bluetooth failed\n", __func__);
        return;
    }

    ret = esp_bluedroid_enable();
    if (ret) {
        ESP_LOGE(GATTS_TAG, "%s enable bluetooth failed\n", __func__);
        return;
    }

    ret = esp_ble_gatts_register_callback(gatts_event_handler);
    if (ret){
        ESP_LOGE(GATTS_TAG, "gatts register error, error code = %x", ret);
        return;
    }

    ret = esp_ble_gap_register_callback(gap_event_handler);
    if (ret){
        ESP_LOGE(GATTS_TAG, "gap register error, error code = %x", ret);
        return;
    }

    ret = esp_ble_gatts_app_register(ESP_APP_ID);
    if (ret){
        ESP_LOGE(GATTS_TAG, "gatts app register error, error code = %x", ret);
        return;
    }

    esp_err_t local_mtu_ret = esp_ble_gatt_set_local_mtu(500);
    if (local_mtu_ret){
        ESP_LOGE(GATTS_TAG, "set local  MTU failed, error code = %x", local_mtu_ret);
    }

    ret = esp_ble_gatts_create_attr_tab(gatt_db, gatts_if, HRS_IDX_NB, ESP_APP_ID);
    if (ret){
        ESP_LOGE(GATTS_TAG, "create attr table failed, error code = %x", ret);
    }
}

在这个示例中，我们使用了ESP-IDF提供的蓝牙协议栈和GATT Server框架，实现了一个简单的GATT Server，并且开启了蓝牙广播和可见性，使得其他蓝牙设备可以扫描到并连接我们的设备。在连接建立后，我们可以向GATT Server中的特定Characteristic写入数据，也可以从特定Characteristic读取数据。