【摘要】 在分析液晶显示(LCD)控制器总体结构的基础上,阐述了用异步FIFO(先进先出)电路来解决显示存储器的并发访问和异步时钟域问题.给出了FIFO电路结构,并对其工作原理进行了分析.为减小亚稳态的出现几率,提高电路的工作稳定性,提出了两种方法来优化FIFO电路.一是用格雷码代替二进制编码,因为格雷码在任意两个相邻的数之间转换时,只有一个数位发生变化,这样可以有效缩短过渡周期.二是用两级触发器来同步输入的异步信号.FIFO电路使用VerilogHDL语言实现,并用Modelsim进行仿真.该设计已经成功运用到一款针对手持设备应用的LCD控制器中,测试结果表明该控制器工作正常,画面稳定、清晰.更多还原

【Abstract】 On the basis of the analysis to the framework of liquid crystal display(LCD) controllers, a method to settle concurrent access of the display storage and asynchronous clock by asynchronous FIFO (first in first out) circuit was studied. The working principle of FIFO circuit structure was analyzed, and two methods were put forward to improve the working stability of the FIFO circuit. One plan was that Gray code was substituted for binary systems because only one bit would change when transform any two numbers between, which was efficient to diminish the interim; another one is to input asynchronous signal by using two level trigger. The FIFO circuit was implemented by VerilogHDL language simulated through Modelsim. The design had been applied to a type of LCD controller aimed at handy equipmenty. The testing results showed that this controller worked well with a stable and vivid display.更多还原