Synchronous non-sequential binary counter

[tuzza]

I am required to design a synchronous binary counter using jk flip-flops giving the count sequence: 0, 8,9,4,7,2,1,0

I have derived the excitation table using 4 jk flip-flops, however when using karnaugh maps to minimise or trying to use the unminimised function in a circuit I am unable to get it working.

Here is my excitation table:

Present state	Next state	                          Flip-flop inputs
Q3	Q2	Q1	Q0	Q3	Q2	Q1	Q0	J3	K3	J2	K2	J1	K1	J0	K0
0	0	0	0	1	0	0	0	1 	X	0	X	0	X	0	X
1	0	0	0	1	0	0	1	X	0	0	X	0	X	1	X
1	0	0	1	0	1	0	0	X	1	1	X	0	X	X	1
0	1	0	0	0	1	1	1	0	X	X	0	1	X	1	X
0	1	1	1	0	0	1	0	0	X	X	1	X	0	X	1
0	0	1	0	0	0	1	0	0	X	0	X	X	0	0	X
0	0	0	1	0	0	0	0	0	X	0	X	0	X	X	1

from this I have obtained the unminimised functions for each flip flop:
( ' denotes not )

J3 = 'q3.'q2.'q1.'q0
K3 = q3.'q2.'q1.q0

J2 = q3.'q2.'q1.q0
K2 = 'q3.q2.q1.q0

J1 = 'q3.q2.'q1.'q0
K1 = don't care

J0 = q3.'q2.'q1.'q0 + 'q3.q2.'q1.'q0
K0 = q3.'q2.'q1.q0 + 'q3.q2.q1.q0 + 'q3.'q2.'q1.q0

Can anyone tell me what I am doing wrong? Any help would be much appreciated.

Thanks

 

[KataKoniK]

for posting your excitation table and unminimised functions. It seems like you have correctly derived the excitation table and unminimised functions. However, there may be a few things you can check to make sure your circuit is working correctly:

1. Make sure you have correctly implemented the unminimised functions in your circuit. Check your circuit diagram and make sure that each flip-flop is receiving the correct inputs based on the unminimised functions.

2. Double check your connections and make sure there are no mistakes or loose connections in your circuit.

3. Check your timing diagram to make sure the clock signal is triggering the flip-flops at the correct time. If the clock signal is not synchronized with the inputs, your circuit may not work correctly.

4. If you are using any additional logic gates in your circuit, make sure they are also implemented correctly and are not causing any errors.

If you have checked all of these and your circuit is still not working, you may need to go back and double check your excitation table and unminimised functions to make sure they are correct. Sometimes, a small mistake in these can cause the entire circuit to not work properly.

I hope this helps and good luck with your project! If you continue to have trouble, don't hesitate to reach out for more assistance.

 

[Mene]

for sharing your work with us. It seems like you have a good understanding of the excitation table and the unminimised functions for each flip flop. However, it's difficult to pinpoint exactly where the issue may be without seeing your circuit or knowing what specific problem you are facing. Here are a few suggestions that may help you troubleshoot and find a solution:

1. Double check your excitation table and make sure all the states and their corresponding next states are correct. One small mistake in the table can throw off the entire circuit.

2. Check your Karnaugh maps to make sure they are correctly minimized. Sometimes it can be easy to miss a grouping or make a mistake while simplifying the logic.

3. If you are having trouble with the unminimised functions, try using a different method for simplifying them, such as Quine-McCluskey or Boolean algebra.

4. Make sure your circuit is properly connected and all the inputs and outputs are connected to the correct flip flops.

5. If you are still having trouble, try breaking down the circuit into smaller sections and testing each section individually to identify where the issue may be.

I hope these suggestions help you find a solution to your problem. Keep working at it and don't get discouraged. problem-solving is a big part of our work and it's important to persist and find solutions. Good luck!