Design Methodology

Technical Description

Introduction

Adder Circuit

**Simulation**

Schematic Diagram

Binary Adder Circuit can be constructed with full adders connected in cascade. Binary adder are available in MSI IC such as 7483, 74283 and 4008. In here, the simulated design of a binary adder circuit uses the MSI IC 7483 (4 BIT FULL ADDER WITH FAST CARRY).

Binary Adder Circuit

The purpose of this project was to design and to simulate a simple 2-digit calculator in which we are free to choose any software to be used. The simulation software that has been use here is NI Multisim 12.0. It has been chosen because it is a learning circuit environment, and contains almost all MSI IC’s capable of designing circuits in a more simple way.

Project Organization

The aim of this project is to simulate a simple calculator using Multisim software. The simulated design must satisfy the scope and limitations attached with the given project. It is then can perform addition, subtraction, multiplication and division that will accept 2-digit inputs (decimal). It does not accept negative input but it can display negative difference. If the product produces overflows, it displays ERR, meaning error. It does not display quotient less than 1 instead the rounded down answer. And lastly, the answer is implemented using five-seven segment displays.

The specifications set out at the beginning of the project were to take the basic block diagram for the 2-digit calculator shown below, design and simulate each section separately using NI Multisim 12.0. Use the Multisim approach with hierarchical design methods to simulate the entire simple calculator design.

Block Diagram

**a Simple**

Calculator

Calculator

It was introduced that the aim of this project was to design and simulate a simple 2-digit calculator. Rather than solve the given problem in one whole large section of it, it was looked at in block diagram form. Each block was designed and tested separately to ensure each individual circuit worked correctly prior to simulating the complete circuit.

Conclusion

Conclusion

Recommendation

Almero, Aaron Marlord

Hernandez, Hazel Ann

Liwag, Eloisa

Caringal, Glenn

Multiplier Circuit

4x4 Multiplier

Hierarchal Circuit Design

2-Digit Adder Circuit

Shift Register

Input Keys

**of**

Background Theory

A calculator is a device that performs arithmetic operations on numbers. The simplest calculators can do only addition, subtraction, multiplication, and division. More sophisticated calculators can handle exponential operations, roots, logarithms, trigonometric functions, and hyperbolic functions.

Shift Registers

A register is capable of shifting binary information in one or both direction. The basic building block of shift registers are the Flip flops. In a modern technology, there now exists registers that may shift to the right or left instead to use Flip Flops that may make the circuit longer; and even a register that acquires both capability to shift to the left and to the right depending on how you will set its mode of operations.

Karnaugh Map

Subtractor Circuit

The circuit for subtracting binary numbers consists of XOR gates which is a 7486 IC. The input carry must be equal to 1 when performing subtraction thus with the controlled inverter (XOR gates) connected to Vcc and an input carry that goes to high when subtraction, we obtained the 2’s complement of the number. With the two’s complement of the number we can perform the subtraction by using the 7483 IC (4-bit Full Adder).

Multiplier Circuit

Rules for Binary Multiplication:

0 x 0= 0

0 x 1= 0

1 x 0= 0

1 x 1= 1

Multiplication takes place in binary numbers by taking n shifts and adds to multiply n-bit binary number. This is called an array multiplier.

The multiplication process involves multiplication of a 2-bit number.

This practical approach leads to easily detect the errors that occurs in the circuits. Also, we are able to design through knowledge of combinational and sequential circuits. It had given us good background in designing the project.

We have realized that the MSI IC helps a lot to shorten the circuit design. Integrated circuits plays an important role in designing a circuit. Its characteristics and specifications produce an ideal and practical design. With a proper connection implemented in their pin assignments you can obtain your design. Though we have not finished the simulation design for this simple calculator and even encountered crucial errors, we have learned how to build its building blocks that may lead to a more improved design in the near future.

As you can see it inputs the decimal 0-9 and outputs its 4-bit binary equivalent. If you have noticed it has only 1 to 9 decimal inputs excluding decimal zero. It does because .The available 74147 is an active low input and output and in the design to be presented here, an inverter (7404) have been used to invert the output in order to obtain the correct 4-bit binary form of the BCD number.

The encoded BCD to its binary form in the simulation process serves as the input of the first shift register. Two shift registers is needed to support the maximum input the project can acquire (2-digit BCD or 8bit binary). The clock of the two registers are then connected to each other as if it receives a clock pulse, it triggers the register to shift the memory registered in it.