算法状态机图在数字系统设计中的应用

Application of Algorithm State Machine Chart in Digital System Design

算法状态机(ASM)图是一种描述时序数字系统控制过程的算法流程图,其结构形式类似于计算机中的程序流程图。传统的数字系统设计方法虽然也可以采用ASM图的方法来描述系统功能,但由于实现时采用标准数字电路芯片,使设计过程缺乏灵活性。随着硬件描述语言(HDL)和可编程逻辑器件(PLD)的飞速发展,今天的数字系统设计者已经有了更多的选择。文中将ASM图、HDL、PLD技术相结合,提出现代数字系统设计的3个步骤首先用ASM图进行系统功能描述,然后将ASM图翻译成HDL,最后用PLD来实现。通过交通灯控制器的设计对每个步骤进行了说明。

The algorithm state machine(ASM) chart is a flow chart used for the description of digital systems. It was used in conventional design of digital systems, but the method is very complex and difficult. The EDA technology introduced the hardware description language (HDL) and the programmable logic devices. Designers can now use them in their designs. But the design methods still stay at “cut and try”. This article introduces three design steps of the digital systems which are combination of the ASM chart and EDA technology. At first, the ASM chart will be drawn according to the function of digital systems given. Then, the ASM chart will be translated into HDL. Finally the design will be compiled into a file and downloaded into CPLD. An example of the design of traffic light controller is given to explain the design procedure.