Digital logic doubt

Question

Counting sequence of 4 bit johnson counter with initial value 0000 is

A. 0 1 3 7 15 14 12 8 0

B.0 1 3 5  7 9 11 13 15 0

C. 0 2 4 6 8 10 12 14 0

D. 0 8 12 14 15 7 3 1 0

Answer 1

Johnson Counter Complements the last bit and thus generates 2N states for N Flip Flops

0000 --> 0

1000 --> 8

1100 --> 12

1110 --> 14

1111 --> 15

0111 --> 7

0011 --> 3

0001 --> 1

0000 --> 0

Thus Option D

Comments

I understood what u said.....But what if initial reading is not given...Then it could be a or d ..Or only d...

I would appreciate ur assistance...

---

In your question suppose initial reading is not given:

All answers start from 0 and the maximum value is 15. Thus we need at least 4 bits and since all answers start from zero we take 0000 as initial reading.

---

in jhonson counter always complement least significant and send it to msb right shifting the bits consequently

0000

1000

1100

1110

1111

0111

1011

0001

0000

thus answer is d