# Birthday date project

Discussion in 'Homework Help' started by saruman42, Dec 7, 2011.

1. ### saruman42 Thread Starter New Member

Dec 7, 2011
2
0
Hello all, I am currently working on a project that requires me to build a circuit on multisim and then breadboard the design. I am currently having trouble in the multisim portion of the project. I'm posting all the information regarding what I have below.

What I'm supposed to do:
Design a combinational logic circuit and display it results on a seven-segment display

I have attached a photo of what I have done.

Birthday Boolean
(sorry, the truth table gets a bit messed up when I copy it in here)

A B C Date a b c d e f g
0 | 0 0 0 0 0 0 0 0 0 0 1
1 | 0 0 1 1 0 0 1 1 1 1 1
2 | 0 1 0 - 1 1 1 1 1 1 0
3 | 0 1 1 2 0 1 0 0 1 0 0
4 | 1 0 0 1 0 0 1 1 1 1 1
5 | 1 0 1 - 1 1 1 1 1 1 0
6 | 1 1 0 9 0 0 0 1 0 0 0
7 | 1 1 1 4 0 0 1 1 0 1 0

Equations:

a = A’BC’ + AB’C
b = A’BC’ + A’BC + AB’C
c = A’B’C + A’BC’ + AB’C’ + AB’C + ABC
d = A’B’C + A’BC’ + AB’C’ + AB’C + ABC’ + ABC
e = A’B’C + A’BC’ + A’BC + AB’C’ + AB’C
f = A’B’C + A’BC’ + AB’C’ + AB’C + ABC
g = A’B’C’ + A’B’C + AB’C’

All together:

(A’BC’ + AB’C) + (A’BC’ + A’BC + AB’C) + (A’B’C + A’BC’ + AB’C’ + AB’C + ABC) + (A’B’C + A’BC’ + AB’C’ + AB’C + ABC’ + ABC) + (A’B’C + A’BC’ + A’BC + AB’C’ + AB’C) + (A’B’C + A’BC’ + AB’C’ + AB’C + ABC) + (A’B’C’ + A’B’C + AB’C’)

Simplified:
a = AB’C + A’BC’
b = A’B + AB’C
c = AC + B'C + AB' + A'BC'
d = A + B'C + BC'
e = B'C + A’B + AB'
f = AC + B'C + AB' + A'BC'
g = A'B' + B'C'

(AB’C + A’BC’) + (A’B + AB’C) + (AC + B’C + AB’ + A’BC’) + (A + B’C + BC’) + (B'C + A’B + AB') + (AC + B'C + AB' + A'BC') + (A'B' + B'C')

NOTE: U7 AND is currently unattached.

Thanks in advance for any help.

• ###### design.jpg
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Last edited: Dec 7, 2011

Apr 5, 2008
15,806
2,390
Hello,

The images don't show as they are links to your local computer.
You can upload the images to our server:

Bertus

saruman42 likes this.
3. ### saruman42 Thread Starter New Member

Dec 7, 2011
2
0
Thanks for the advice, I attached the photo.

4. ### Georacer Moderator

Nov 25, 2009
5,151
1,266
From what I understand, you want to display the rolling message "01-21-94". Check for a bit this link (http://en.wikipedia.org/wiki/7_segment), and see which segment (a,b,c...) is which. Are you sure you have your outputs correctly? Because, for instance, {abcdefg}={000001} isn't the code for 0.