Does the carry-out pin of IC 4510 go high after powering up?

Discussion in 'General Electronics Chat' started by szabikka, Jan 16, 2016.

  1. szabikka

    Thread Starter Member

    Sep 3, 2014
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    Hello everyone!

    I came across the following problem. I have created a counter circuit in two different simulators. The circuit is the same in both cases, however I have noticed a difference when I started the simulation. In one of the sims the carry-out pin goes high immediately after the sim is started (power is applied), while in the other the opposite is true, the carry-out stays low when I start the sim.

    Clock pulses are not coming in yet, the load input is tied low, and the up/down input (pin 10) is tied low too, since I want a down counter. Which simulator is right? Does the carry-out pin of the 4510 go high when power is applied or does it stay low?
     
  2. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    No chance to implement that on a breadboard with a slow clock and maybe a scope?
     
  3. atferrari

    AAC Fanatic!

    Jan 6, 2004
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    No way to check the datasheet?
     
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Datasheet says the carry out is high by default and goes low when output is 9 when counting up. It then appears that the next more significant bit increments on the low-to-high transition as carry-out pin returns to HIGH state.

    So, to answer your question, the pin does go high on startup.
     
  5. szabikka

    Thread Starter Member

    Sep 3, 2014
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    I have tried it on a breadboard. When I completely remove the astable NE555 (clock pulse provider) from the board the carry-out pin has a stationary voltage of 0,07V, which is low as I use a 12V battery as the power supply. When I reconnect the 555 (but inhibit the pulses to reach the clock input) the carry-out fluctuates between 0,14 and 0,08 V and goes high when a carry occurs. So it appears that after applying power and resetting the counter (00:00) the carry-out is at a low logic value (this kind of contradicts the datasheet).
     
  6. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Look for the datasheet of your specific part/manufacturer.
     
  7. szabikka

    Thread Starter Member

    Sep 3, 2014
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    Okay, I have found out the problem. If you connect the up/down pin to ground (down counting mode) and reset the 4510 to 0 it will count as a carry as carry occurs at 0 to 9, even when there aren't any clock pulses coming in, so the carry-out pin will go low. If you connect the up/down pin to the power rail (up counting mode) and reset the counter to 0 it will not be count as a carry, since carry appears at 9 to 0 transition in up counting mode, and the carry out remains high. All in all, one of the simulators is faulty.

    The datasheets were not too helpful, since don't talk too much about the carry-out phenomena.

    Thanks for the answers. ;)
     
  8. dl324

    Distinguished Member

    Mar 30, 2015
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    In the future, post a schematic and names of simulators.

    What datasheet are you using? I've looked at a few and some are better than others. All provide a logic diagram so you can analyze carry out behavior.

    EDIT: Correct spell checker corrections...
     
    Last edited: Jan 16, 2016
  9. szabikka

    Thread Starter Member

    Sep 3, 2014
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    Funny thing is that they're basically identical. One of them is Circuit WIzard Pro 1.60 the other one is Circuit Wizard 2 Student Edition. The CW 2 SE is the one with the correct carry-out behavior.
     
  10. szabikka

    Thread Starter Member

    Sep 3, 2014
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    Sorry, I forgot to post the schematics. This is the most basic circuit that can demonstrate the problem. CW1 is the wrong one and CW2 is the good one, as it can be seen on the multimeters.
    CW1.JPG
    CW2.JPG
     
  11. hp1729

    Well-Known Member

    Nov 23, 2015
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    Yep. Carry out should be high then go low on Carry Out whether you are counting up or down. What is Preset doing?
     
  12. szabikka

    Thread Starter Member

    Sep 3, 2014
    77
    1
    Hi hp1729. Do you want to know what the preset enable pin is doing on the 4510 ic in general, or your question is concerned about my circuit?
     
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