# Truth table to Logic gates converter

Thread Starter

#### chroncile

Joined Mar 27, 2010
13
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

#### beenthere

Joined Apr 20, 2004
15,819
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.

Thread Starter

#### chroncile

Joined Mar 27, 2010
13
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

Thread Starter

#### chroncile

Joined Mar 27, 2010
13
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

#### beenthere

Joined Apr 20, 2004
15,819
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.