Truth table to Logic gates converter

Discussion in 'Homework Help' started by chroncile, Mar 27, 2010.

  1. chroncile

    Thread Starter New Member

    Mar 27, 2010
    13
    0
    Are there any programs out there that can convert truth tables to logic gates?

    I need to convert this:

    DECIMAL INPUTS SEGMENT OUTPUTS
    DIGIT D C B A A b c d e f g
    0 0 0 0 0 1 1 1 1 1 1 0
    1 0 0 0 1 0 1 1 0 0 0 0
    2 0 0 1 0 1 1 0 1 1 0 1
    3 0 0 1 1 1 1 1 1 0 0 1
    4 0 1 0 0 0 1 1 0 0 1 1
    5 0 1 0 1 1 0 1 1 0 1 1
    6 0 1 1 0 0 0 1 1 1 1 1
    7 0 1 1 1 1 1 1 0 0 0 0
    8 1 0 0 0 1 1 1 1 1 1 1
    9 1 0 0 1 1 1 1 0 0 1 1
    10 1 0 1 0 X X X X X X X
    11 1 0 1 1 X X X X X X X
    12 1 1 0 0 X X X X X X X
    13 1 1 0 1 X X X X X X X
    14 1 1 1 0 X X X X X X X
    15 1 1 1 1 X X X X X X X
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    There may be, but IC's with internal logic to do that already exist. Grab a data sheet for a 7447 to see how it's done.
     
  3. chroncile

    Thread Starter New Member

    Mar 27, 2010
    13
    0
    I googled 7447 datasheet, but I couldn't find a logic gate representation; that's what I am suppose to do. The teacher told us to do each segment; use a K-Map to find out the simplified expression for each segment and then group all the segments into one big simplified expression.

    I'm having trouble doing it, though. Can you please help me with segment b?

    D C B A b
    0 0 0 0 1
    0 0 0 1 1
    0 0 1 0 1
    0 0 1 1 1
    0 1 0 0 1
    0 1 0 1 0
    0 1 1 0 0
    0 1 1 1 1
    1 0 0 0 1
    1 0 0 1 1
    1 0 1 0 X
    1 0 1 1 X
    1 1 0 0 X
    1 1 0 1 X
    1 1 1 0 X
    1 1 1 1 X
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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  5. chroncile

    Thread Starter New Member

    Mar 27, 2010
    13
    0
    What do you mean work backwards? I already finished the assignment, but I would still like to know what you mean by working backwards.

    Also, is there a program I can use to draw my circuit? I have to draw a copy of the circuit, but it would take me way too long to do it by hand.

    Thanks :)
     
  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Work back from each segment. Look for common states shared by two or more segments.

    As for schematics, I use my CAD program. Some members use MS Paint.
     
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