SCYC55830 58063282A ABB 触发脉冲板

SCYC55830 58063282A ABB 触发脉冲板

SCYC55830 58063282A针对主从RS触发器，当C=1时，主锁存器输出随输入S和R不断变化。如上图所示，假设主锁存器输入S为1，R为0，此时主锁存器输出Q被置位为1；当S变为0，R变为1，Q复位为0；当S和R都变为0，则Q保持不变为0。若此时C由1变为0，则从锁存器接收主锁存器的输出，整个触发器输出为Q等于0。由此看来，触发器zui终输出的结果与整个C=1期间的输入信号变化有关，而非只与下降沿到来时刻S和R的值有关。因为如果当下降沿到来的时刻S=R=0，单看S和R，无法直接知道输出Q的取值，必须要考虑前一时刻的Q。 而对于边沿D触发器，相当于输入只有01和10，zui终的输出Q就是下降沿或者上升沿到来时刻输入D的值，只需考虑当前时刻的输入值。 SCYC55830 58063282A由此观之，两者的区别就在于主锁存器的区别，一个是带输入控制的SR锁存器，一个是D锁存器，前者输出要考虑整个C=1期间输入的情况，而C=1时后者输出Q就等于输入D。脉冲触发和边沿触发这两个短语很形象地形容了这一区别。

SCYC55830 58063282A ABB 触发脉冲板

SCYC55830 58063282A For the master/slave RS flip-flop, when C=1, the master latch output constantly changes with the input S and R. As shown in the figure above, assuming that the main latch input S is 1 and R is 0, the main latch output Q is set to 1; When S becomes 0 and R becomes 1, Q is reset to 0; When S and R both become 0, Q remains unchanged. If C changes from 1 to 0 at this time, the output of the main latch is received from the latch, and the output of the entire trigger is Q equal to 0. From this point of view, the result of the final output of the trigger is related to the change of the input signal during the whole period of C=1, and not only to the values of S and R at the arrival of the falling edge. Because if S=R=0 when the falling edge arrives, you can't directly know the value of the output Q by looking at S and R alone, you have to consider the previous time Q. For the edge D flip-flop, the input is equivalent to only 01 and 10, and the final output Q is the value of the input D when the falling edge or rising edge arrives, and only the input value at the current moment is taken into account. SCYC55830 58063282A From this point of view, the difference between the two is the difference between the main latch, one is the SR latch with input control, one is the D latch, the former output to consider the entire C=1 period of input, and C=1 when the latter output Q is equal to the input D. The phrase pulse trigger and edge trigger vividly describe this difference.

SCYC55830 58063282A ABB 触发脉冲板