I am trying to set up several 4017 counters to count from 1 to 30. The info I have shows me that as the first one counts to 10 it trigers the next stage to count to 1 and then wait until the next tenth count before another count is registered. can anyone tell me how to wire up the counters so that it produces a continuous count starting from 1 to 30 and then reset back to 1. Thanks in advance
On Thu, 07 Jul 2005 12:15:44 -0000, Lindsay wrote in Msg.
You can't without some "glue logic". Note that, at any time, at least one of the 10 outputs of the 4017 is active. This is what you'll have to deal with first; it should get you started.
My guess is that the 4017 was originally designed to deal with Nixie tubes and may not be the right choice for a more-than-10 stage Johnson counter. If I were you I'd solve the task with a shift register. More straightforward solution and lower part count.
robert
If what you want is a one-of-30 count then this is tricky with a 4017 as one of the 10 outputs will laways be active. If all you want is a divide by 30, use one stage for divide by 10, and a second stage clocked by the carry-out of the first, with Q3 connected to reset to do divide by 3
The circuit below shows two 4017 counters for 18 counts. You can expand it to whatever you want with additional counters and one AND gate for each counter.
But you need to connect the gate input to pin 3 of all counters except one. The gate connected to pin 11 will start the sequence.
The gates are shown using 2 diodes and a resistor, but you can substitute a quad AND gate chip.
-Bill
Correction to other post.
I'm not sure it will work for more than 2 counters. When power is applied, the counters will reset so that all pin 3's are at high level. This means only one gate input should be tied to pin 3 which will be enabled at power on. If all the other gates are tied to pin 11, there will be one LED lit on pin 3 of the remaining counters. And this is illegal, since there should only be one on at a time.
It's a little more complicated than I thought. It works well as shown for 2 counters, but I'm not sure right now how to expand it to 3 or more counters.
-Bill
if you particularly want to use 4017s, i think you could cascade them synchrounously by clocking them al with the input and using the 10th output of the first counter as the clock enable of the 2nd counter, the actual tenth output would then have to be derived from anding the tenth output of the first counter with the first output of the 2nd stage, same for the next stages etc ... this means 3 stages wont give you 30 counts anymore however.
Colin =^.^=
output
next
however.
the datasheet explains it in more detail.
Colin =^.^=
Why not just a flip-flop and a counter strapped to divide by
15, and a couple of '154s? I'd think, to make a chaser with a shift register, you'd have to take heroic measures to give it glitch immunity, i.e. so you can be assured that there's only the one bit chasing around. (diode OR? whatever.) Do they make '154s in a skinnydip? (2X 24-pin .6 DIPs is a lot of board real estate!) Or even surface mount?Silly me - four seconds at Google:
Good Luck! Rich
Somehow I doubt that nixie tubes were the intended target of the 4017 - it can't drive them directly, as the active high output is wrong, and the high voltage will fry it. TTL parts 7441 and 74141 are made to drive nixies directly, and work fairly well [though the Russian copy of the 74141, the K(M)155ID1, is a great improvement].
I completely agree with the shift register as solution to the count by 30 problem. If you choose presettable parts with over 30 stages, you can use stage 31 to trigger a preset to all zeroes but "1" in the LSB position; this should keep glitches from permanently hosing the output - unless you happen to get the glitch that clears your lone circulating high bit! Actually only the IC which starts the LSB would need to be presettable - a reset will do for the others.
-- -------------------- Alan "A.J." Franzman Email: a.j.franzman [ A T ] verizon [ D O T ] net --------------------
Shift register solution posted at...
Newsgroups: alt.binaries.schematics.electronic Subject: One of Thirty Problem (from S.E.D) - OneOfThirty.pdf Message-ID:
Probably more complex than needed, but I'm an Analog guy ;-)
...Jim Thompson
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I love to cook with wine. Sometimes I even put it in the food.
I had good luck using the 74HC164, 8 bit shift registers. The noise immunity is half the supply voltage, so you would need 3 volt noise spikes to cause trouble on a 6 volt supply.
It's a much simplier circuit and doesn't need any extra logic other than to get it going when power is applied. And you can add as many registers as needed.
The idea is to reset the registers and then apply a high level to the data input and one clock edge to load one bit when you turn the thing on.
Here's an example:
-Bill
Lindsay wrote:
The data sheet shows you how to do that. But if it's LEDs you're driving then you only need two 4017 counters ( you can drive 1 out of 100 LEDs this way): View in a fixed-width font such as Courier. . . . ------- . +---4017---+ | | . CLOCK>--------------|CK Q0|-.----||>|--+-|-[R]------+ . | | | | | | | . | . | | | | | c . | . | | | | | |/ . | . | | | | | -| . | | | | | | | |\\ . +--|MR Q9|-. ||>|--+ | | e . | |__ | | -------- | | . gnd-+--|EN | | | gnd . | | | ------- | . | CARRY | | | | | . +----------+ |----||>|--+-|-[R]--|---+ . | | | | | | | . | | | | | | c . +----------------------+ | | | | | |/ . | | | | | |-| . | | | | | | |\\ . | +---4017---+ | ||>|--+ | | e . +--|CK Q0|-[Rb]--\\ | -------- | | . | | | | | gnd . | Q1|-[Rb]--\\| | ------- | . | . | | | | | | . | Q2|-[Rb]--\\| ----||>|--+-|-[R]--|---+ . | | | | | | | | . +--|MR Q3|--+ | | | | | c . | |__ | | | | | | | |/ . +--|--|EN | | | | | | |-| . | | | | | | | | | | |\\ . gnd | | CARRY | | | ||>|--+ | | e . | +----------+ | | -------- | | . | | | | gnd . | | | | . +----------------+ +--------------------------+ . . .
"Lindsay" schreef in bericht news: snipped-for-privacy@corp.supernews.com...
Overlooking the questions and the answers so for it's not clear to me what you really need. So some questions:
- Do you need to use 4017?
- What output pattern do you need? For instance one out of thirty clockpulses, a continuous moving 1 out of 30 pins or what?
petrus bitbyter
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