Logic Design Course Project

The description of a course work

The course work is dedicated to designing logic circuits.

The purpose of implementing a course work on "Logic design" is acquaintance of the student with design techniques of simple logic circuits manually" and with the use of EDA tools.

Logic circuits are subdivided into two classes: "combinational" and "sequential” (or FSM) ".

Combinational is called the logic circuit, the output signals of which depend only on current values of input signals.

Sequential (FSM) is called the circuit, the output signals of which are defined not only by current values of input signals, but also depend on a sequence of values of input signals in the past.

The course work consists of two parts:

• Synthesis of a combinational circuit.

• Synthesis of FSM.

1. Synthesis of a Combinational Circuit

A student is given one of the below-mentioned task variants. It is required to define the system of Boolean functions describing the given device, make minimization of the obtained functions and develop the combinational circuit by the following ways:

• Design of the circuit into AND, OR, NOT basis

• Transition into NAND, NOR basis and design of combinational circuits in these basis

• Representation of functions in polynomial form

• Design of functions using decoder

• Design of implementing functions with the help of multiplexers

• Creation of gate-level description of implemented circuit.

Types of tasks

Task 1.1.

Design a circuit of the device that performs the conversion of input binary decimal code into output binary decimal code.

The weights of input and output binary-decimal codes are presented in Table 1.

Table 1

Number of variant	Input code p1 p2 p3 p4	Output code p1’ p2’ p3’ p4’
1.	8 4 2 1	7 4 2 1
2.	7 4 2 1	5 4 2 1
3.	7 4 2 1	8 4 2 1
4.	7 4 2 1	2 4 2 1
5.	5 4 2 1	2 4 2 1
6.	2 4 2 1	8 4 2 1
7.	5 3 2 1	2 4 2 1
8.	4 3 1 1	8 4 2 1
9.	5 2 1 1	2 4 2 1
10.	6 3 1 -1	3 3 2 1
11.	4 3 1 1	7 5 3 -6
12.	8 4 2 1	5 3 2 -1
13.	5 3 2 -1	2 4 2 1
14.	8 4 2 1	2 4 2 1
15	5 3 2 -1	7 5 3 -6
16	4 3 1 1	6 4 1 -2
17	6 4 1 -2	4 3 1 1

The values of numbers of binary-coded decimal code with weights p₁ p₂ p₃ p₄ are defined by the following formula:

X = x₁p₁ + x₂p₂ +x₃p₃ + x₄p₄ =x_ip_i ,

where p_i – weight of i-th bit of a tetrad.

In addition to codes with the given weights for coding decimal numbers, other codes are also used: a code with excess 3, code 2 out of 5, biquinary code.

These codes are presented in Table 2.

Table2

Number	Code with excess 3	Biquinary code	Code 2 out of 5
0	0011	010 0001	00011
1	0100	010 0010	00101
2	0101	010 0100	00110
3	0110	010 1000	01001
4	0111	011 0000	01010
5	1000	100 0001	01100
6	1001	100 0010	10001
7	1010	100 0100	10010
8	1011	100 1000	10100
9	1100	101 0000	11000