# Jk flip flop up/down synchronous counter

Joined Jun 3, 2016
3
Hi
I am having problems with simulation for this particular counter. below are all my diagram including truth table and multisim simulation. the problem is its only going from 0-4 and vice versa. It should go like 0,1,2,3,4,0,1,2,3,4

#### dl324

Joined Mar 30, 2015
11,317
Welcome to AAC!

Is this homework?

Your truth table would be easier to read if you narrowed column width, used borders, and centered data in the cells.

Joined Jun 3, 2016
3
Yes this is my Homework assignment. sorry i am still trying to make sense of it all thats why its a bit unitidy below are my k maps and equations

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#### dl324

Joined Mar 30, 2015
11,317
Yes this is my Homework assignment.
Guidelines are different for responding to homework questions.

Why are they teaching you to use 'A' for MSB? If you study datasheets from the 1970's, it's more typical for 'A' to be LSB.

Kindly label your Kmaps JA, KA, JB, KB, etc. You have a bunch of y= equations, but I can't tell which variables they're for.

Wouldn't it make more sense to use Ja or JA instead of y?

#### WBahn

Joined Mar 31, 2012
26,074
MOD NOTE: Moved to Homework Help

#### WBahn

Joined Mar 31, 2012
26,074
Yes this is my Homework assignment. sorry i am still trying to make sense of it all thats why its a bit unitidy below are my k maps and equations
Taking the time and effort to make your work tidy, even (or especially) if that means taking chicken-scratch drawings and redoing them solely for the purpose of cleaning them up, is time very well spent. This is particularly important when asking others for assistance or what you turn in for grading. But it is extremely helpful even if you are the only person that will see them. Cleaning them up forces you to think about why it isn't clean and what will make it clean -- that forces you to think about what you are doing in a coherent and focused way. It also lets you review what you have accomplished to this point and perhaps spot errors or things that haven't been taken into account.

Joined Jun 3, 2016
3
Guidelines are different for responding to homework questions.

Why are they teaching you to use 'A' for MSB? If you study datasheets from the 1970's, it's more typical for 'A' to be LSB.
View attachment 154599

Kindly label your Kmaps JA, KA, JB, KB, etc. You have a bunch of y= equations, but I can't tell which variables they're for.

Wouldn't it make more sense to use Ja or JA instead of y?
yes you are right
i guess for this problem A=m b=Qa c=Qb d=Qc
do you find anything wring with the circuit diagram

#### dl324

Joined Mar 30, 2015
11,317
i guess for this problem A=m b=Qa c=Qb d=Qc
You should have 6 equations.
do you find anything wring with the circuit diagram
I'm not even going to try to read your schematic without first seeing how you arrived at the equations.

Obviously you know your solution is incorrect. If it wasn't, you wouldn't be asking for help.

Why do you have the variables mostly listed A,B,C and then you reversed the order in the J/K columns. Is A the MSB in the left 8 columns and something else in the right 6?

Why do you have don't cares for some counts above 4 and not all of them?

Your work is very sloppy. I'd give you a failing grade just for messy work.

#### dl324

Joined Mar 30, 2015
11,317
Upon closer examination, you appear to be very confused.

Sometimes you have 4 variables, sometimes you have 3. Sometimes D is LSB and sometimes it's C.