how to wire and trigger the 4017 to count only one cycle per pulse?

Thread Starter

NOISEBOB

Joined Jul 7, 2019
48
Hi

i'm having a hard time figuring out how to make the 4017 only count once..
i want to be able to make the 4017 count to 4 when fed a HIGH signal and then stop.

then start the count from 1 again when it gets another HIGH signal.

reading these ones just made me more confused:
https://forum.allaboutcircuits.com/...017-decade-counter-once-and-then-stop.112915/
https://www.instructables.com/How-to-make-a-4017-Decade-Counter-Run-for-One-Cycl/
https://www.petervis.com/dictionary-of-digital-terms/4017-counter/4017-counter.html

shouldn't it be possible to do using just one HIGH signal (from any source) and a 4017 chip, do i need to also include a multiplexer or something of that kind?
 

Thread Starter

NOISEBOB

Joined Jul 7, 2019
48
hi Bob,
This is one option.
E
Thanks, I'll give it a go..

By using a 4093 I'd make one oscillator to control the tempo of the counter and and one (much slower) oscillator to trigger when it should count..

so that it counts 1, 2, 3, 4, pause, 1, 2, 3, 4, pause, and so on.
Or just a push button pulse trigger to go 1, 2, 3, 4 and then wait for the next push.

That is my idea.

I'll breadboard your circuit later today.
 

Thread Starter

NOISEBOB

Joined Jul 7, 2019
48
Optionally, I could use a mux.... to switch between the counter and the pause.

But that seems like a silly workaround and i'd not have full control of the counter and have it reset to count 1 after each cycle.
 

Ian0

Joined Aug 7, 2020
2,227
Connect the “4” output to “clock inhibit”. The clock will then be inhibited when it gets to 4. Connect the pulse that restarts it to RESET.
If it is a slow clock (ie slower than the time you are likely to hold the restart button down) then you don’t need any denouncing on RESET, but it will remain at zero until you release the button.
if you want it to start counting the moment that the button is pressed, then you will need a capacitor/resistor network on RESET.
 

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Audioguru again

Joined Oct 21, 2019
3,193
My 3V LED chasers use a 74HC4017 for its high output current but very low pausing current.
A monostable blinks each LED brightly but for only 30ms to keep the average current low.
It chases around and around 3 times then stops at the 9th LED and pauses, then it starts on the 2nd LED and chases again.
Two AA alkaline cells power it 24/7 for 3 months.
 

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AnalogKid

Joined Aug 1, 2013
9,257
By using a 4093 I'd make one oscillator to control the tempo of the counter and and one (much slower) oscillator to trigger when it should count.. so that it counts 1, 2, 3, 4, pause, 1, 2, 3, 4, pause, and so on.
Sit with output #4 high during the pause? Or sit in the zero state (outputs 1-4 all low)?
Or just a push button pulse trigger to go 1, 2, 3, 4 and then wait for the next push.
That is a different design from the first one you described. And again, what state is the counter in during the "wait"?

ak
 
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