Solving Mod 13 Ripple Counter with D Flip Flop

[d_b]

Homework Statement

I'm working on this problem but everytime I tried to walk through my answer it doesn't seem right.

I wanted to built a ripple counter, up counter with mod 13 using D flip flop.

Homework Equations

present state ABCD - 0000-->1101
next state ABCD - 0001-->0000

Q(t+1) = Dq

The Attempt at a Solution

I first built the state diagram going from 0000 to 1101 then back to 0000.

Now the textbook said to use take the compliments of the output from the D flip flop. So what I did I took the compliment of the output(next state) and the unused state (14 and 15 as don't care) and by k-map i constructed a formula for the 4 D-FF. However as soon as I hit 13(1101) it will not go back to 0000.

The other approach is: I took the output from the next state and the unsued state(1110 and 1111 as don't care states), using k-map again i constructed a formula for the sum of product of the 4 D-FF. But agian it will not go from 1101 to 0000.

Then I redo it by using complements output of the next state with k-map to built the formula for the FFs without the unused state and it still doesn't work.

I redo it agian by using output of the next state with k-map to built the formula for the FFs without the unused state and still doesn't work.

I know that I'm doing something wrong during the process, however I'm not sure howelse to built this FFs.

 

[d_b]

oh...this is not a homework either, its my exam review questions...

 

[Mene]

It seems like you have made several attempts to solve this problem and have tried different approaches, but have not been successful. Have you considered seeking help from a classmate, professor, or tutor? They may be able to provide valuable insights and help you identify where you may be going wrong in your problem-solving process. Additionally, have you checked your calculations and diagrams to ensure they are correct? It may also be helpful to break down the problem into smaller steps and double check each step to ensure accuracy. Keep in mind that solving problems in science often requires trial and error, so don't get discouraged and keep trying different approaches until you find the correct solution.