Why does my sequential circuit keep getting 1111?

Question

I have an assignment to create circuit on this website called Circuitverse The question was to design 4-bit counter circuit with 1 external input using D flip flops, whereby when input=0, count sequence is 8->14->9->5 (repeat), push the undesired states to 14 and when input= 1, count sequence is 6->3->14->9 (repeat), push the undesired states to 3.

This is the transition table that I have created:

As well as the Kmap and the boolean expression I get from it.

And this is the circuit that I created in Circuitverse:

As you can see the sequential circuit is clearly displaying wrong output and I can't seem to find what is the problem. I hope someone can clarify or point out at which part I did something wrong.

Edit:

I tried inputting the expression properly now but still the same, I tried checking the transition tables for any problems but don't find any

Here is my updated diagram:

Edit 2: Never mind. I did not incorporate it properly. Here's the updated diagram:

I think you've missed a connection potentially (the red line). Also I'm not sure where you are incorporating your input? Could you label that on your simulation? — Entropy, May 26 '23 at 07:34
You're not incorporating Input properly into your expressions, it should be Input' for the input low, e.g. D4 = Input'AB'C'D + Input'ABCD' + Input(D' + B + AC + A'C') - and it's missing from the diagram anyway. — Finbarr, May 26 '23 at 07:54
Ok, i tried incorporating it properly but still same issues, are there any mistakes that i made that i miss, i updated my diagram on the post — MUHAMAD IRSYAD BIN MAT YAAKOB, May 26 '23 at 08:32
Where have you incorporated it? It looks just the same. Without it, any input that goes high in either case will go high all the time, hence being stuck on 1111. — Finbarr, May 26 '23 at 08:34
Okay, this might be stupid question how do I properly incorporate it? — MUHAMAD IRSYAD BIN MAT YAAKOB, May 26 '23 at 09:18
Nevermind, i finally make it work. Thank you all for the comment! — MUHAMAD IRSYAD BIN MAT YAAKOB, May 26 '23 at 10:27

Why does my sequential circuit keep getting 1111?

0 Answers0