目前,有很多的硬件描述语言.由于应用的范围不同,因而产生了不同级别的描述语盲.例如,有系统级、指令集级、寄存器传输级、门级及电路级的硬件描述语言.我们研制的CAD硬件描述语言的主要目标在于建立一个统一的描述方法和提供一个标准的数据交换格式.因而它主要用来描述电路的拓扑结构以及电路中所包含模块的电学参数和芯片物理实现时的几何参数. 由于逻辑网络有层次结构,因此,一个待设计的电路可以用不同的设计级来完成.本系统提供三个设计级,它们是门级、触发器级和功能块级.因此,我们可以把不同级别的部件抽象地看成一个黑盒子,然后用它的输入输出信号作为参数来定义.例如用门和触发器可以设计一个寄存器,然后把寄存器又作为设计计数器的一个基本部件,在一个更大的 At present, there are a lot of hardware description languages, and different levels of descriptors are generated due to different applications, for example, system-level, instruction set level, register transfer level, gate level and circuit level hardware description language. The main goal of the developed CAD hardware description language is to establish a uniform description method and to provide a standard data exchange format.Therefore it is mainly used to describe the circuit topology and the circuit contains the electrical parameters of the module and the chip physical implementation Geometric Parameters Because of the hierarchical structure of the logic network, a circuit to be designed can be implemented with different design levels. The system offers three design levels, gate level, flip-flop level and block level, so that we Different levels of components can be abstracted as a black box, and then use its input and output signals as a parameter to define.For example, with the door and trigger can design a register, then the register and design counter as an essential part of the A bigger one