Tugas 8 [Dwi Nita Maulida] Function of CL

 FUNGSI KOMBINASI LOGIKA

Chapter Objective

. Distinguish between half-adder and full-adder.

. Use BCD-to-7-segment decoders in display systems

. Apply multiplexer in data selection

. Use decoders as multiplexer

Half Adder

Simple Binary Addition

0 + 0 = 0 zero plus zero equals zero

0 + 1 = zero plus one equals one

1 + 0 = 1 one plus zero equals one

1 + 1 = one plus one equals zero with a carry of one

Basic Adder 

Adder are important in computers and also in other types of digital systems in which numerical data are processed

definition : The half-adder accepts two binary digits on its inputs and produces two binary digits on its outputs, a sum bit and a carry bit Program Studi T. Elektro FT - UHAMKA

The Full Adder

definition  : The Full-Adder accepts two input bits and an input carry and generates a sum output and an output carry

The basic different between a full-adder and a half-adder is that the full-adder accepts an input carry.

The full-adder must add the two input bits and the input carry. From the half-adder, the sum of the input bits A and B is the exclusive-OR of those two variables. For the input carry (Cin) to be added to the input bits, it must be exclusive-ORed, and last yield the equation for the sum output of the full-adder

This is mean that to implement the full-adder sum function, two 2-input exclusive-OR gates can be used . The first must generate the term AB and the second has as its inputs the output of the first XOR gate and the input carry. The output carry is a 1 when both inputs to the first XOR gate are 1s or when both inputs to the second XOR gate are 1s. The output carry of full-adder is therefore produced by the inputs A ANDed with B and AB ANDed with C

Full Adder from Two Half-Adder Circuits

Determine the outputs for the inputs shown

Parallel Binary Adder

A single full-adder is capable of adding two 1-bit numbers and an input carry. To add binary numbers with more than one bit, we must use additional full-adders.

 Truth Table for a 4-Bit Parallel Adder

Use the 4-bit parallel adder truth table to find the sum and output carry for the following two 4-bit numbers if the input carry (Cn-1) is 0. A4A3A2A1 = 1100, B4B3B2B1 = 1100

 n=1, A1 = 0, B1 = 0 and Cn-1 = 0 n=2, A2 = 0, B2 = 0 and Cn-1 = 0 n=3, A3 = 1, B3 = 1 and Cn-1 = 0 n=4, A4 = 1, B4 = 1 and Cn-1 = 1

Σ1 = 0 and C1 = 0 Σ2 = 0 and C2 = 0 Σ3 = 0 and C3 = 1 Σ4 = 1 and C4 = 1

11000

Comparators

 The basic function of a comparator is to compare the magnitude of two binary quantities to determine the relationship of those quantities

  1-Bit Comparator

  2-Bit Comparator 

 4-Bit Comparator

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