The example of taximeter system that designed based on the top-to-down and modular concept is given to induce the common digital-system design idea with VHDL and ISP devices.

• 介绍VHDL语言及在系统编程技术的应用,结合自顶而下模块化设计的出租车计费系统实例,给出使用VHDL语言和在系统编程器件设计数字系统的基本思路。