摘要
介绍了基于MSI可编程计数器74LS161的时序逻辑电路设计技术,目的是探索MSI可编程计数器实现一般时序逻辑电路的扩展应用方法,即以计数器Q3,Q2,Q1,Q0端的代码组合表示时序逻辑电路的各个状态,由输入变量控制计数器的EP,ET及■端,综合利用计数、置数、保持功能,使计数器的状态变化满足所要求的时序,用计数功能实现"次态=现态+1"的二进制时序关系,用置数功能实现"次态=预置数"的非二进制时序关系,用保持功能实现"次态=现态"的自循环时序关系。所述方法的创新点是提出了MSI可编程计数器改变应用方向的逻辑修改方法。
The design technique of the sequential logic circuits based on MSI programmable counter 74LS161 is presented.The purpose is to investegate a common method to realize the sequential logic circuits.In the design,the code combination of Q3,Q2,Q1 and Q0 is taken to denote the states of the sequential logic circuit,the input variables are adopted to control the EP,ET and ports of LD,and the data-setting,counting and keeping functions are used to allow the change of the counter state to meet the requirement of the sequence,which means that the counting function is used to realize the binary sequential relation（″next state=present state＋1″）,the data-setting function is used to achieve the non-binary sequential relation（″next state=setting data″）,and the keeping function is used to carry out the self-looping sequential relation（″next state=present state″）.This is a new method for MSI programmable counter to change its application direction.
出处
《现代电子技术》
2010年第11期167-170,共4页
Modern Electronics Technique
