Need help with a mod-6 counter using JK flip flops w/ control bit

In summary, the conversation discusses the assignment of creating a six-state up/down counter using flip-flops. The first part of the assignment involved designing a circuit using D flip-flops which worked perfectly in both directions. The second part requires converting the design to use JK flip-flops, but the extra control bit is causing confusion. The student has created an excitation table and JK k-maps for both C=0 and C=1, but is unsure how to incorporate the control bit into the new k-maps. They are seeking help in understanding the logic of utilizing JK flip-flops for 3 input bits and a control bit.
  • #1
makattack

Homework Statement


[/B]
I am currently working on an assignment in which I create a six-state up/down counter. The purpose is to understand the functionality of flip-flops within a circuit among other things.

There are 3 input bits (Q2,Q1, Q0), and a 4th control bit (C) which determines the direction that the counter runs. Naturally I derived a design from 3 next-state function 4x4 k-maps, and I created a design utilizing D flip flops, which runs perfectly forwards and backwards.

The second part asks me to convert from a D-ff design to using JK flip flops. I mostly understand the logic of how a JK flip flop works, but I can't for the life of me figure out how to fit that extra control bit into the translation.

Homework Equations

The Attempt at a Solution


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My trouble comes in keeping the circuit bi-directional. I am very confused about what to do with the control bit. I created an excitation table for the next states, which I believe is correct, and conversions for the six JK k-maps (K2, K1, K0, J2, J1, and J0). However, I now have two sets of J & K values, one for C=0 and one for C=1.

In trying to work it out, I populated the 6 k-maps with the proper data (only C=0) and constructed a function/circuit, but of course it only clocks in one direction whether C is set to 0 or 1. What am I supposed to do with the control bit when I translate to the new k-maps for K2, K1 etc... which each only take the three Q input bits?

What am I missing in the logic of utilizing JK flip flops for 3 input bits when there is the control bit as well?

Hopefully that's clear, I'm sure it is just a conceptual problem I am having trouble figuring out. If anyone wants me to upload my excitation table or any other part I've done so far, let me know. Any help is greatly appreciated!
 
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  • #2
Welcome to the PF. :smile:

Yes, please upload your work for the D-FF version and your work so far for the JK-FF version. That will help a lot in our efforts to help you out. :smile:
 

1. How does a mod-6 counter using JK flip flops with a control bit work?

A mod-6 counter is a type of sequential circuit that counts in a specific pattern, in this case from 0 to 5. JK flip flops are a type of flip flop, which is a basic building block of sequential circuits. The control bit is used to enable or disable the counter. The counter works by using the J and K inputs of the flip flops to toggle the outputs in a specific sequence, based on the control bit.

2. What are the advantages of using JK flip flops in a mod-6 counter?

JK flip flops have the ability to toggle their outputs, making them very useful in counting circuits. They also have the capability to be configured as either a positive-edge or negative-edge triggered flip flop, providing flexibility in circuit design. Additionally, using JK flip flops can save space and reduce complexity in the circuit compared to using other types of flip flops.

3. How many JK flip flops are needed for a mod-6 counter?

A mod-6 counter requires three JK flip flops. Each flip flop represents one bit in the counter, with a total of three bits needed to count from 0 to 5. The outputs of the three flip flops are then combined to form the six possible states of the counter.

4. What is the purpose of the control bit in a mod-6 counter using JK flip flops?

The control bit is used to enable or disable the counter. When the control bit is set to 1, the counter will count as normal. However, when the control bit is set to 0, the counter will be disabled and will no longer count. This can be useful in certain applications where the counter needs to be turned on or off based on certain conditions.

5. How can I implement a mod-6 counter using JK flip flops with a control bit?

To implement a mod-6 counter using JK flip flops with a control bit, you will need to first design the circuit using a truth table or Karnaugh map. Once the circuit is designed, you can then use the appropriate logic gates and connect them to the JK flip flops to implement the desired counter sequence. It is important to also consider the clock frequency and timing requirements when designing the circuit.

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