Your circuit should have $3$ type of flip$-$flop. JK$,$ D and T Flip$-$flop. If you unable to fulfil the above

requirement, you can also do it with a single type of flip$-$flop $($but no more $"$A$"$ grade, there will be some

mark deduction on this$).$

Design a $4-$bit counter with one external input using flip$-$flops according to the above requirement. The

circuit will receive a one$-$bit input. Different Input will have different count sequence. An example table is

shown below.

Example Table

Input $=0,$ Count Sequence is $12412($repeat$),$ push the undesired states to $1$

Input$=1,$ Count Sequence is $11473($repeat$),$ push the undesired states to $11.$

Question:

Ques No:$19,$ Input$=0,81495($repeat$),$ all undesired state go to $14$

Ques No:$19,$ Input$=1,6->3->14->9($repeat$),$ all undesired state go to $3$

i$)$ State transition diagram

ii$)$ State transition table

iii$)$ Simplification using K$-$Maphelp