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Logic gate into boolean equation

Discussion in 'Electronic Basics' started by Jibbed, Nov 17, 2003.

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  1. Jibbed

    Jibbed Guest

    Hope this is the right group for this.

    I've made a big circuit in digital works that makes a 7 Segment digital
    display count from 0 to 9. I now have to make the Boolean equations from the
    circuit. One for each segment.

    Here is the first segment (8kb):

    Would it be:
    _ _ _ _ _ _ _ _ _ _
    SEG A = A B C D + A B C D + A B C D

    Or is that total crap?!

  2. Jon,

    It is not total crap, but it's not correct either. Besides, the negation
    lines do not come through on the right place. Below I use a notation that
    fits better in a typed text.

    SEG A = /(/A * /B * /C * D + /A * B * /C * /D + /A * B * C * /D)

    Re-reading your equation and shifting the negation lines a little bit, I
    guess it's the same that you (want to) write.

  3. Jibbed

    Jibbed Guest

    Hi peter,
    Thanks! That was what I was looking for! Never seen it written like that but
    it does makes sense to me, sort of confirmed what I'd hoped. I had the
    equation I made from the truth table which had an OR instead of a NOR that I
    changed it to. I was hoping that I could just "NOT" the whole equation which
    it seems like I can do.

    But, I need it written in the form I have it written, which I'm hoping would

    (note the absence of a line immediately above the OR (+). Correct?)

    Anyway you've been lots of help. I just need to get cracking on the rest of
    the segments now!...

  5. Jibbed

    Jibbed Guest

    Phew! Good to hear.


  6. Jon,

    It's correct. The way I initially learned to write it, but, as I said, not
    easy to type. Modern logic developing programs tend to use the "!" for the
    NOT, "|" for the OR and "&" for the AND. Learned from the C language. You'll
    met them when you continue to study digital developement.


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