基于节点编号的多层液晶菜单界面设计，适用于按键少的简单界面。程序流程逻辑清晰，增删节点无需修改主程序部分，可移植性好.-Multilevel menu design base on Node Numbering, applies to the simple interface with little keys. Program logic is clear, nodes are added or removed without having to modify the main program