ESP32 蓝牙介绍。蓝牙可分为控制器? (Controller) 和主机 (Host) 两大部分：控制器包括了PHY、Baseband、Link Controller、Link Manager、Device Manager、HCI 等模块，用于硬件接口管理理、链路路管理理等等；主机则包括了了 L2CAP、SMP、SDP、ATT、GATT、GAP 以及各种规范，构建了了向应?用层提供接口的基础，方便便应?用层对蓝牙系统的访问。主机可以与控制器运行在同一个宿主上，也可以分布在不同的宿主上。(ESP32 Bluetooth introduction. Bluetooth can be divided into two parts: controller (Controller) and host (Host). The controller includes PHY, Baseband, Link Controller, Link Manager, Device Manager, HCI and so on. The specification provides the basis for providing interface between the user interface and the user interface to facilitate access to Bluetooth system. The host can be carried on the same host with the controller, and can also be distributed on different hosts.)