Информатика и выч. техника \ Компьютерные операционные системы

Структура и элементная база цифровых систем. Реализуемая логическая функция. Нагрузочная способность, страница 13


                D  T  Q                          C       

                         _                                                                                                     Qn+1= D

                C      Q                           D   

Q    

                                                      _

                                                      Q

Синхронизируемый фронтом D- триггер

 Условное обозначение и логическая схема

 


             D  TT   Q                              D                 и- не

                                              C                                                   и- не                    и- не

             C                                         и                                                                                        и- не     Q   

                         _                   V        

             V         Q                                     

 


                                                                              и- не

                                                                                                   и- не                                                    _                  

и- не           и- не    Q

не

Сигнал V  блокирует работу триггера

( триггер с "защелкой").

C* = V * C

Временная диаграмма работы триггера

 

                C

 

                D 

 


               Q 

                _

               Q     

 


                V

     

Варианты использования D- триггера  вместо триггеров типа  T-  и  JK            

 


                                       D    TT                                               или             D      T     

                                                      Q                                                                             Q

                                                                                   J     

                                                                                                                                      _

                                      C              _                          K            или             C              Q 

                                                      Q

                                                        

T- триггер ( счетный )

Условное обозначение, характеристическое уравнение и таблица истинности

                                                                  _                       _                         T       Qn+1    

                  TT  Q                            Qn+1= T  *  Qn + T  *  Qn                        0       Qn       

_      

              T                                                                                                      1       Qn

_

Q

 Словари переходов основных типов триггеров

                                                         RS                                            JK                                                                  

                           Fq                                                                                                            T              D

                                                 S                   R                     J                       K

                             0                  0                    x                      0                       x                  0               0

                             1                  x                    0                      x                       0                  0               1                   

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