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I have a need for a circuit with cascading outputs such as a 4017 chip. I want every output to be able to reset the circuit using a jumper. I was thinking to make a pcb with solder jumpers so one gets to choose which of the outputs resets the circuit by soldering one of the jumper's pads.

example with 4 outputs: 1000 0100 0010 0001 1000

Problem #1: when an output resets the circuit I want the first output to be on. So I want to start at 1 and not at 0.

Problem #2: when the circuit is powered on. I also like the circuit to start at 1

The outputs need to pull an input of an attiny or atmega chip with internal pull-up resistors to 0V.

I was thinking to use a CD4078BE which is an 8 input NOR / OR gate. The idea was to tie all 4017's outputs to the 4078's inputs. The inverted output of the 4078 would only be '1' if all 4017's outputs are low (so in reset/power up state).

Is this a viable approach or am I overlooking something?

enter image description here

bask185
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  • No idea what you mean, include some **schematics**. Also search for "4017 circuit" in Google for example and press the **Images** tab, then you will see plenty of schematics using the 4017 and you can use that as inspiration. – Bimpelrekkie Jan 11 '22 at 08:49
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    I thought the question made sense first but CD4017 etc is a decade counter, not a binary counter. Simply call pin Q0 for "1"? – Lundin Jan 11 '22 at 08:53
  • When the 4017 resets, it resets to zero. There are no options to purchase a version of the 4017 that resets to a different value. Think again. – Andy aka Jan 11 '22 at 08:53
  • When the MR pin is asserted (taken high) the least significant output (out0) will be set. –  Jan 11 '22 at 08:56
  • added a schematic. @bim – bask185 Jan 11 '22 at 09:00
  • Bimpelrekkie. I have and I know how to wire one, but what I was not sure of was if Q0 would be '0' or '1' after a reset. @lundin, Why do you even start talking about a binary counter? I never mentioned that. The comments of Andy aka and James are contradicting. Which one is true? I thought that Q0 was 0 after a reset, that is why this question exists – bask185 Jan 11 '22 at 09:05
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    Q0 goes high on a reset. Andy and James are saying the same thing. – HandyHowie Jan 11 '22 at 09:09
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    When a reset occurs, the only option with the 4017 is to set the Q0 output, not any other of the Q1 to Q9 outputs. –  Jan 11 '22 at 09:10
  • @HandyHowie Andy litterly says that the 4017 resets to zero which is not true. James says differently and is correct. I consulted that datasheet and I will post an answer – bask185 Jan 11 '22 at 09:12
  • Zero is Q0 high. – HandyHowie Jan 11 '22 at 09:13
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    **IT RESETS TO ZERO** – Andy aka Jan 11 '22 at 09:40
  • @bask185 Because asking how starting from 1 in a binary counter would make perfect sense. But not when using a decade counter, then it's all just a matter of nomenclature. Name the first output pin whatever you like. It would seem that this is all just a misunderstanding about how CD4017 works though? It might not be obvious whether or not it activates the first output out of reset, I suppose. – Lundin Jan 11 '22 at 10:10
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    *Andy litterly says that the 4017 resets to zero which is not true.* Sorry to disappoint you but Andy is correct. After a reset, Q0 becomes 1. There is no way to change that. If you want an output that becomes 0 after reset, use any of the other outputs. Also stop thinking that the 4017 counts: 0000, 0001, 0010, 0011 etc (binary) as it does not. It counts like so: 0001, 0010, 0100, 1000 etc, the "1" shifts up and only one output is 1 at any time. – Bimpelrekkie Jan 11 '22 at 10:11
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    Though he may be right 'technically', Andy himself has not explicitly explained or mentioned that Q0 was '1' in the zero state while this question is precisely about this. By just saying that it resets to zero while not mentioning that Q0 is '1' in that same state (which would solve my problem). I thought he was implying that Q0 was '0'. His overal negative tone and attitude towards me with ''think again" in combination with 'neglecting' to mention that Q0 would be '1' makes me think that he does not even want to help me. This is how it strikes me, though I know it is not true. – bask185 Jan 11 '22 at 10:31

2 Answers2

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The friendly datasheet of CD4017 reveals the following timing spec:

enter image description here

That is, out of reset, output pin '0' is active, just like you want. If you don't want it to be active then simply don't use that pin and start counting from '1'...?

Lundin
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Your circuit will probably work but you overlooked figure 18 in the data sheet:enter image description here

The reset input is asynchronous. The SR flipflop stretches the reset signal so that it will reset all the D flipflops. Your connection has a slivered reset signal.

stretch
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