VHDL语言设计数字系统，VHDL是Very High Speed Integrated Circuit Hardware Descr iption Language 的缩写，意思是超高速集成电路硬件描述语言。本课程设计分析了现代城市交通控制与管理问题的现状，结合城市交通的实际情况阐述了交通灯控制系统的工作原理。编写了程序控制8255A可编程并行接口芯片，使红、绿、黄发光二极管按照十字路口交通信号灯的规律交替发光，模拟了交通信号灯简单的工作。-VHDL language design digital systems, VHDL is the Very High Speed Integrated Circuit Hardware Descr iption Language acronym, meaning high speed integrated circuit hardware descr iption language. The curriculum design of the modern urban traffic control and management of the status quo, with urban transport in the Shi Ji Qingkuangchanshu a traffic control Ji Tong Deng works. Prepared a program control 8255A programmable parallel interface chip to red, green, Huang Faguang diode in accordance with the laws of intersection traffic lights turn light to simulate the simple task of traffic lights.