Developing a Logisim Circuit for a Lift Simulation System

This assignment focuses on developing a Logisim circuit for a lift simulation system. It includes the truth table representation, K-map, and testing of the circuit.

Running head: COMPUTER SYSTEMS AND NETWORKS
COMPUTER SYSTEMS AND NETWORKS
Name of the Student
Name of the University
Author Note

1COMPUTER SYSTEMS AND NETWORKS
Introduction:
In this assignment the objective is to develop a Logisim circuit for a lift Simulation system.
The lift has two inputs namely C and D respectively. Both has different values which
represents the floor number of the lift from 0 to 7. Among the floors 0, 4 and 6 are private
floors and the lift is not supposed to stop or start from those floors. Also, the lift movement is
unsuccessful if the destination floor is same as the starting floor. The lift movement is
successful for all the other floor to floor input. The input C is modelled by C1, C2 and C3 of
one bit and input D is modelled by D1, D2 and D3 with each of one bit. C and D input
representation table:
Successful operations from C to D:
1 to 2, 2 to 1, 1 to 3, 3 to 1, 1 to 5 , 5 to 1, 1 to 7, 7 to 1, 2 to 3, 3 to 2, 2 to 5, 5 to 2, 2 to 7, 7
to 2, 3 to 5, 5 to 3, 3 to 7, 7 to 3, 5 to 7, 7 to 5
Truth Table representation of C and D for Successful operation:
C1 C2 C3 D1 D2 D3 Successful
Operation (S)
0 0 1 0 1 0 1 to 2

2COMPUTER SYSTEMS AND NETWORKS
0 1 0 0 0 1 2 to 1
0 0 1 0 1 1 1 to 3
0 1 1 0 0 1 3 to 1
0 0 1 1 0 1 1 to 5
1 0 1 0 0 1 5 to 1
0 0 1 1 1 1 1 to 7
1 1 1 0 0 1 7 to 1
0 1 0 0 1 1 2 to 3
0 1 1 0 1 0 3 to 2
0 1 0 1 0 1 2 to 5
1 0 1 0 1 0 5 to 2
0 1 0 1 1 1 2 to 7
1 1 1 0 1 0 7 to 2
0 1 1 1 0 1 3 to 5
1 0 1 0 1 1 5 to 3
0 1 1 1 1 1 3 to 7
1 1 1 0 1 1 7 to 3
1 0 1 1 1 1 5 to 7
1 1 1 1 0 1 7 to 5
K-MAP of the Sum Of Product (SOP) form:
D1D2D3
C1C2C3 000 001 011 010 110 111 101 100
000 0 0 0 0 0 0 0 0

3COMPUTER SYSTEMS AND NETWORKS
001 0 0 1 1 0 1 1 0
011 0 1 0 1 0 1 1 0
010 0 1 1 0 0 1 1 0
110 0 0 0 0 0 0 0 0
111 0 1 1 1 0 0 1 0
101 0 1 1 1 0 1 0 0
100 0 0 0 0 0 0 0 0
S = ∑
m
(10,11,13,15,17,19,21,23,25,26,29,31,41,42,43,47,57,58,59,61) with no Don’t cares.
Solving This K-map gives Minimized Boolean expression of output S.
Minimized Boolean Expression:
S = C1'C2C3'D3 + C3D1'D2D3' + C2'C3D1'D2 + C1C3D1'D3 + C2C3D2'D3 + C1'C3D1D3
+ C2'C3D2D3
Logisim Circuit Diagram:

4COMPUTER SYSTEMS AND NETWORKS
Testing:
C1C2C3 = 001(C = 1) and D1D2D3 = 000(D = 0)

5COMPUTER SYSTEMS AND NETWORKS
C1C2C3 = 010(C=2) and D1D2D3 = 111(D=7)

6COMPUTER SYSTEMS AND NETWORKS
C1C2C3 = 111(C=7) and D1D2D3 = 110(D=6)
C1C2C3 = 011(C=3) and D1D2D3 = 101(D=5)

7COMPUTER SYSTEMS AND NETWORKS
Thus it can be seen from the testing that the lift is working according to the rules given in the
truth table. In the first test the C input is 1 and the D output is 0 and as the destination floor is
private it can be seen the LED of successful operation is OFF. In the second test C=2 and
D=7 and thus it is a permitted movement of lift and so the LED is ON. In the third test C=7
and D=6, so the lift movement is not permitted as D=6 is a private floor. In the fourth test
current floor C = 3 and destination floor D = 5 and hence the lift movement is permitted and
so as the Output LED S is ON.
Conclusion:
In conclusion it can be said that the operation of the given lift with specified conditions is
successfully implemented in Logisim using basing 2 input primary gates (AND, OR and
NOT). The testing of the circuit shows desired results as the output LED turns ON and off
according to the truth table of C1,C2,C3 and D1,D2,D3 inputs. A further advanced circuit
like limiting circuit operation based on number of unsuccessful attempts and turning ON
circuit based on certain numbers of successful operations can be integrated with the current
circuit with counters and other extra advanced digital devices like flip flops. However, this
will increase the complexity of design and make the circuit really huge and difficult for
operation and thus this advanced design is not chosen for implementation due to scope of the
length of the assignment. The basic floor to floor operation of the circuit is appropriate and
the circuit has been built using the Minimized Boolean logic expression of the Output S with
the help of K-map reduction technique as shown in the middle of the report.