Host/Controller Interface (HCI)

router

•Reused from standard Bluetooth specification, with new additional commands for low energy-specific functions
从标准的蓝牙规范重用，添加一些针对低功耗特性的命令。
•Thin layer; doesn‟t perform any processing 轻层，不执行任何处理
•In a dual-chip solution (with separate host and controller) allows for host to communicate with controller over a standard interface (UART, USB, SDIO, etc.)
在双芯片的解决方案（host和controller分开的情况），允许host通过标准接口（UART/USB/SDIO等）与controller进行通讯。
•Used internally by the CC2540 BLE protocol stack for communication between higher and lower layers
•Also allows for custom “vendor-specific commands”. In the CC2540, vendor-specific commands can be used by an external source to directly interface with the entire stack or application. This is called a “Network Processor”

总结：Host 与 Controller 之间通讯的桥梁