扭环型计数器自启动设计的逻辑修改方案

摘要

为了克服目前在保持右移移位寄存器内部结构不变的基础上只求解第1位触发器的激励函数设计方法的局限性,分析了扭环形计数器工作时的状态转换过程,提出在不改变右移移位、取反循环移位的状态变化规律时可对任何一位触发器的激励函数进行逻辑修改的设计方案,给出了在次态函数卡诺图上进行激励函数最小化求解与检查无效状态所赋次态值及逻辑修改同步进行的自启动设计方法,简化了扭环形计数器的设计过程.%States transition in twisted ring counter working progress is analyzed. A new design scheme that the logic function modification is made to excitation function in any counter is put forward, where this scheme does not conflict with the right shift and back cycling shift rules. In present framework design, the only solution needs to be worked out is that the excitation function for the first flip-flop. The method is modified while remaining the inside structure of right shift register invariant. It is aimed to explore the logic function modification of self-correction in twisted ring counters. The method is to minimize the excitation function with next state Karnaugh map, to check the next state values in invalid state and to carry out self-correction synchronously. Design progress of twisted ring counter is simplified.