GATE Overflow | Digital Logic | Test 1 | Question: 1

Question

A sequential circuit has three D flip-flops $A, B, C$ and one input $X$. The circuit is described by the following input equations:

$$D_A = (B\bar C + \bar BC ) X + (BC + \bar B \bar C) \bar X , \\D_B = A , \\D_C = B$$

What is the next state for the circuit for $X=0$ when present state $A, B ,C$  is $0, 0, 0$?

• A. 0 1 0
• B. 1 0 0
• C. 0 0 0
• D. 0 0 1

Answer 1

As it is D flip flop
B next = Db = A which is 0,
C next = Dc = B which is 0,
A next = 1 as ( not X. not B. not C ) = 1

Comments

Problem statement was very confusing for me, especially the notation put me into confusion.