# 29-0 counter using JK Flip-Flop

#### oncbeuddy

Joined Feb 16, 2020
2
How do I go about doing this? I've been able to do a 9-0 counter, but I'm clueless as to how start on doing a 29-0 counter.

Schematic for 9-0 counter using JK FF:

#### ericgibbs

Joined Jan 29, 2010
9,574
hi o,
Welcome to AAC.
E

Joined Mar 10, 2018
3,909
The core of the design is two simple tasks -

1) How many J-Ks needed to represent 0 - 29 ?
2) Then ask yourself, what state do I have to detect to flip the counter from "last"
state to "beginning" state, and design that decoder....

Regards, Dana.

#### dl324

Joined Mar 30, 2015
10,072
Welcome to AAC!
but I'm clueless as to how start on doing a 29-0 counter.
What kind of counter designs have you been studying? There are a couple ways to approach a problem like this. Have you studied how to implement a binary to BCD converter?

Post your work for the decade counter and the work you've done for the 29-0 counter.

EDIT: I studied your counter circuit a bit and see that you're using the set/reset inputs on some of the flip flops. A typical counter design uses gating logic, not the set/reset inputs. The only times I've seen them used are when the counter has a set option like set to 9 or set to 0.

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#### oncbeuddy

Joined Feb 16, 2020
2

What I have here repeats the 29-20 count. Basically it goes like this:

1. Counter counts down from 29-20 properly.
2. After counter reaches 20, it resets to 29 again before counting down properly all the way down to 0.

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#### dl324

Joined Mar 30, 2015
10,072
What I have here repeats the 29-20 count.
Somehow I don't think this is what you were asked to do. It's more typical for a student to be asked to actually design a counter, not sling gates around trying to find something that works.

Could you post the entire text of the problem and describe what you've covered in this class?

Your schematic drawing style is very difficult to read. Neatness matters a lot in schematics. Professionals never place wires over components. The schematic editor you're using introduces extraneous connection dots; you shouldn't run wires over them because it looks like a connection.