logic gates: not 1 not 0 but somthing in between, what happened??!!

Discussion in 'Digital Circuit Design' started by Just me1, Sep 5, 2017.

  1. Just me1

    Thread Starter Member

    Sep 3, 2017
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    1
    So. I was working on my simulated computer circuit and my simulator uses 5v as high (1) and 0 as low (0)
    But for some reason im getting 2.5v
    should i be worried about the real thing having that? Or is it just something in the simulation, and how do i fix it?
     
  2. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    now if any one needs a photo of that part of the circuit, ill upload it
     
  3. ScottWang

    Moderator

    Aug 23, 2012
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    Yes, you should do that and upload them as 800x600 jpg, and provide some more info.
     
  4. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    Ok. Will do soon. at school
     
  5. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
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    This is it
     
  6. ScottWang

    Moderator

    Aug 23, 2012
    6,256
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    Is this a school project?
     
  7. ScottWang

    Moderator

    Aug 23, 2012
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    The photo unclear.

    If you use 5V for the cmos Vcc power supply in the real world, normally you won't get 2.5V, unless the ic is damaged.

    If you want to check where is the problem then you can split the circuit as 4 parts and simulates each part to make sure which part has problem to get 2.5V.
     
  8. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    Alright. Thanks, btw im at shool and my pc is at home so new pic will come later then
     
  9. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    Might be the vcc, becouse my simulator doesnt use the pin and just has magic power out of nowhere
     
  10. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    No. But when im finished with school 2 yrs im going to do OR designing and finding and solving the problems in circuits OR be someone who fixes it ( soldering, measuring etc. ) but im not sure what i am going to choose, but that i will see in the future
     
  11. bertus

    Administrator

    Apr 5, 2008
    18,368
    3,519
    Hello,

    I made some comments on your picture:

    Just_20170905_071551_comment.jpg
    Bertus

    PS can you post a screenshot of the circuit, that will be sharper as a picture with your phone.
     
  12. WBahn

    Moderator

    Mar 31, 2012
    22,880
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    You've got several gates that have floating inputs. That is very bad in real life. How simulators handle it varies quite a bit.

    It would really help if you could tell us WHICH signals on that schematic are misbehaving and what the signals are on all of the gates that feed into those signals.

    Also, is this part of some big, complicated schematic that was all put together before any of it was simulated at all?
     
  13. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    I simulated them individually and after that i put it all together, first i had the alu with manual inputs, but now i added ram and registers, but after that i removed the ram becouse it lagged way too much for me, and im used to lag, but it is the register read function that isnt working properly, the register is the same as the ram, only 4 bits less and only 1 adress,

    When i tested the register read and just about every function with logic inputs there was no problem, and after i connected it to the counter stuff went wrong
     
  14. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    I dont remember which signal. Cant screenshot right now becouse im not at home, will do when i get there
     
  15. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    Yea. But my pc is old and isnt connected to the internet, so i have to make a screenshot, and put it on a usb and then into the laptop
     
  16. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    You guys need to see the whole thing or the problem area?
     
  17. Just me1

    Thread Starter Member

    Sep 3, 2017
    59
    1
    The problem is solved by magic, and now it could load a or b and also add and sub, no. It cannot add and sub yet. The register doesnt stay on at loading. But thats an easy fix.

    Thanks for your efforts WBahn , bertus , and ScottWang !! :)
     
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