1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Logic Networks/Seven Segment Displays

  1. Sep 23, 2010 #1
    1. The problem statement, all variables and given/known data
    Here's the problem:

    Design a logic network that can display the characters in “APPLE” on a sevensegment
    display unit. Write the truth table for the output functions C0-C6, minimize them
    by using Karnaugh Map, and implement using discrete logic gates.
    (Hints: Character “A” will be displayed if segments (C0, C1, C2, C4, C5, C6) of a 7-
    segment display are turned on and segment (C3) is turned off. Since only 4 characters
    will be displayed, input of 2 bits to encode them will be needed for the given design.)

    Now, where I get confused is when it says an input of 2 bits to encode them will be needed. I understand that technically only 2 bits are needed, but I do not understand how to implement it using only 2 instead of 4. I've been searching and thinking of different ways to do it but I am stumped.

    2. Relevant equations
    Not quite applicable

    3. The attempt at a solution
    With 2 bits to work with:
    00 = A
    01 = P
    10 = L
    11 = E
    Code (Text):

    A   B   C0  C1  C2  C3  C4  C5  C6
    0   0   1   1   1   0   1   1   1
    0   1   1   1   0   0   1   1   1
    1   0   0   0   0   1   1   1   0
    1   1   1   0   0   1   1   1   1
    But what is the point of using a K Map for this? I am almost sure this is where I am wrong but I have no idea what to do?

    Any help will be greatly appreciated! Thanks

    Attached Files:

    Last edited by a moderator: Sep 23, 2010
  2. jcsd
  3. Sep 23, 2010 #2


    User Avatar

    Staff: Mentor

    Welcome to the PF.

    Everything you've done looks correct. Now just do the 7 K-maps (or just write the 7 equations) that define the logic that drives the 7-segment displays. The same logic is repeated at each display, and drives the 7 segments based on that 2-bit input AB.

    BTW, I edited your post to insert Code tags around your table. This preserves the column alignment.
  4. Sep 24, 2010 #3
    Thanks a million berkeman, I think I got it all figured out!
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Logic Networks/Seven Segment Displays