CS 2420 Lab 6
Topics: Combinational logic function design, optimization and implantation
Build a circuit to display a decimal digit in a 7segment component. In Logicworks, use a hex
keyboard to generate an input combination rather
than have four binary switches. Because the display
can be in the range of 0-9 and A-F, the 7-segment
should display “E”rror for any input that is not a
decimal number.
a
f
b
g
c
e
d
Labels for the LED segments:
SA = a
SB = b
SC = c
SD = d
SE = e
SF = f
SG = g
For example, for input 0; a, b, c, d, e, and f will glow while g remains off.
T1. Make the truth table for the 7-segment component
LogicWorks provides a 7-segment display component. Find the labels for all segments. Fill in the
following truth to display the correct number or “E”.
I3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Input
I2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
I1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
I0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
SA
SB
Output
SD
SE
SC
SF
SG
0
1
2
3
4
5
6
7
8
9
E
E
E
E
E
E
T2. Make K-Maps
Based on the truth table, draw the K-map for each segment
I1,I0
00
SA
I3,I2
11
10
I3,I2
00
01
11
10
I1,I0
00
SC
I3,I2
01
11
I3,I2
I3,I2
I1,I0
00
01
I1,I0
00
01
10
00
01
11
10
SG
00
01
11
10
I1,I0
00
11
10
I3,I2
11
10
01
11
10
00
01
11
10
I1,I0
00
SF
11
01
00
01
11
10
SD
10
00
01
11
10
SE
I3,I2
01
I1,I0
00
SB
00
01
11
10
01
11
10
T3. Find simplified logic functions
Now, optimize logic functions for the segments based on their K-maps. Write down the optimized
functions
SA =
SB =
SC =
SD =
SE =
SF =
SG =
T4. Build the circuit in LogicWorks
Print out your circuit after showing it to your instructor for approval and submit it with all your work.