How to manage logic gates with pulses?

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daipapagaya

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For example, using a momentary push button (normally off), 3 led and the logic gates needed, how can i do this?.

- 1st pulse. If all leds are off, turn on the first.
- 2nd pulse. If led 1 is on, turn on 2 and 3.
- 3rd push. If all leds are on, turn off all.

Of course, logic gates must be maintained in position between pulses.

I know how to do this using static switches, so there is always tension, but with momentary the logic of the circuit dissapears after the first pulse .... Any ideas?.

thanks
 
At least two ways to do this:

1. 3 flip-flops
2. Binary counter that resets after 3rd bit set (0--> 1--> 2--> 0--> 1--> 2--> ...)
 
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How can you get three states out of two flip-flops? There are only two outputs (unless you count the Q-bar ones, which are only the inverse of the Q outputs).

Either this won't work or I'm missing something obvious here ...
 
carbonzit said:
Four sequential states? How?
Click to expand...
Look at BrownOut's sequence. It's a binary sequence of the two FF outputs. Two bits give you four states. You hook the two FFs up as a 2-bit counter to get the four states.

Edit: For the op's requirement you would configure the FFs to count states 1, 2, and 4, skipping state 3. (See attached)

 
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So you'd need an AND gate to generate state 4, correct?
And how do you get the FFs to skip state 3?

Just saw your attachment and am studying it. I see you're using J-K FFs.
 
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Yes, I just added the attachment. J-K FFs are easier then D FFs for this type of circuit since they require less (no) external gating.

Edit: No, you don't need any external gates for 4 states either. See the attached for a 2-bit, 4-state counter configuration of the two FFs

 
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