Homework SourseDesign a sequential circuit with two D flipflops A and B and
Design a sequential circuit with two D flip-flops, A and B, and a single input x, that behaves as follows: When x = 1, the circuit goes through the state transition: 00 to 11 to 01 to 10 and back to 00, and repeats the sequence. When x = 0, the state of the circuit remains the same. Show the state diagram, state transition table, and the resulting circuit diagram.
Solution
The state transition table
STATE
INPUT
NEXT STATE
A
B
X
A
B
0
0
0
0
0
0
0
1
0
1
0
1
0
0
1
0
1
1
1
0
1
0
0
1
0
1
0
1
1
1
1
1
0
1
1
1
1
1
0
0
X\\AB
00
01
11
10
0
0
0
1
1
1
0
1
0
1
DA = x’A + AB’ + xA’B
X\\AB
00
01
11
10
0
0
1
1
0
1
0
0
0
1
DB = x’B + xB’
| STATE | INPUT | NEXT STATE | ||||
| A | B | X | A | B | ||
| 0 | 0 | 0 | 0 | 0 | ||
| 0 | 0 | 1 | 0 | 1 | ||
| 0 | 1 | 0 | 0 | 1 | ||
| 0 | 1 | 1 | 1 | 0 | ||
| 1 | 0 | 0 | 1 | 0 | ||
| 1 | 0 | 1 | 1 | 1 | ||
| 1 | 1 | 0 | 1 | 1 | ||
| 1 | 1 | 1 | 0 | 0 | ||
