The general process of BLE connection establishment

The general process of BLE connection establishment

1. Before starting to connect with Client

1. ESP_GATTS_REG_EVT			注册
2. ESP_GATTS_CREATE_EVT			创建
3. ESP_GATTS_START_EVT 			启动
4. ESP_GATTS_ADD_CHAR_EVT 		添加特征
5. ESP_GATTS_ADD_CHAR_DESCR_EVT	添加特征描述 

1) Registration: ESP_GATTS_REG_EVT

Call esp_ble_gap_set_device_name(char *)to set the name of the Bluetooth device;

Call esp_ble_gap_config_adv_data(esp_ble_adv_data_t *adv_data)to configure broadcast data;

Finally, call the esp_ble_gatts_create_service(esp_gatt_if_t gatts_if, esp_gatt_srvc_id_t *service_id, uint16_t num_handle)specified gatts_ifsum service_idto create the service (the bottom layer btc_transfer_context()implements the creation of the service and the call of the callback function by calling).
When the service is created, the callback function is triggered to profilereport the status and service ID. Service_idFor subsequent additions included serivcesand characteristics/descriptorall need to be used.
The ESP_GATTS_CREATE_EVTevent is triggered at the same time .

2) ESP_GATTS_CREATE_EVT

Call esp_ble_gatts_start_service(uint16_t service_handle)to start the service;

Call again esp_ble_gatts_add_char(uint16_t service_handle, esp_bt_uuid_t *char_uuid, esp_gatt_perm_t perm, esp_gatt_char_prop_t property, esp_attr_value_t *char_val, esp_attr_control_t *control)to add features (feature UUID, feature value descriptor attribute permission, feature attribute, feature value, attribute response control byte).
Triggers ESP_GATTS_START_EVTand ESP_GATTS_ADD_CHAR_EVTevents.

3) ESP_GATTS_START_EVT

(slightly)

4) ESP_GATTS_ADD_CHAR_EVT

Get feature value call esp_err_tesp_ble_gatts_add_char_descr(uint16_t service_handle, esp_bt_uuid_t *descr_uuid, esp_gatt_perm_tperm, esp_attr_value_t *char_descr_val, esp_attr_control_t *control)to add feature descriptor.

5) ESP_GATTS_ADD_CHAR_DESCR_EVT

(slightly)

2. After starting to connect with Client

1. CONNECT_EVT			连接
2. ESP_GATTS_MTU_EVT	
3. GATT_WRITE_EVT 		(client)写(server)事件
4. ESP_GATTS_CONF_EVT 	配置事件
5. GATT_READ_EVT		(client)读(server)事件

Reference

https://blog.csdn.net/zhejfl/article/details/85136102#comments_14573948