1. Counter Design
M R Khandker

2. State diagram
000
001
010
100
101
110
Design a synchronous counter of the following sequence:
0 -> 1 -> 2 -> 4 -> 5 -> 6 -> 0
The counter has 6 different states

3. Excitation table J K
Q(t+1) 1
Q~(t) J K
Q(t)
Q(t+1) X 1

4. LSB A B C JA KA JB KB JC KC X 1

5. BC BC 00 01 11 10 X 1 00 01 11 10 1 X A A Kc
= B~ Jc
= B~ 00 01 11 10 X 1 00 01 11 10 1 X A A KB
= C~ JB
= B~C 00 01 11 10 X 1 00 01 11 10 1 X A A KA
= BC~ JA
= BC~

6. C A B K J Q Q’ K J Q Q’ Q’ K J Q

7. ?
111
000
001
010
100
101
110
What happens if the counter starts with a non valid state?
011

8. BC BC 00 01 11 10 X 1 00 01 11 10 1 X A A Kc
= 1 Jc
= B~ 00 01 11 10 X 1 00 01 11 10 1 X A A KB
= 1 JB
= C 00 01 11 10 X 1 00 01 11 10 1 X A A KA
= B JA
= B