DLD-1.docx - EGEE245L - L06: ENCODER DECODERS USING 74155...

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EGEE245L - L06: ENCODER ANDDECODERS USING 74155 CHIPIntroductionDecoder is a combinational circuit that has ‘n’ input lines and maximum of 2n output lines. Oneof these outputs will be active High based on the combination of inputs present, when thedecoder is enabled. That means decoder detects a particular code. A demultiplexer is the oppositeof a multiplexer. There is one data input, whose value appears on one of the data outputs,depending on the value of the control inputs. A demultiplexer (or demux) is a device that takes asingle input line and routes it to one of several digital output lines. A demultiplexer of 2n outputshas n select lines, which are used to select which output line to send the input. A demultiplexer isalso called a data distributor.Lab Tasks (Simulations)I. Review 2-TO-4 Decoder ( Using Standard Logic Gates )In the 2 to 4 line decoder, there is a total of three inputs, i.e., A0, and A1and E and four outputs,i.e., Y0, Y1, Y2, and Y3. For each combination of inputs, when the enable 'E' is set to 1, one ofthese four outputs will be 1.
II. Two 2-TO-4 Decoder Using 74LS155 Chip: ( Show Datasheet
III. Single 3-To-8 Line Decoder ( Just a Different Configuration of the Chip )The 3 to 8 line decoder is also known asBinary to Octal Decoder. In a 3 to 8 line decoder, thereis a total of eight outputs, i.e., Y0, Y1, Y2, Y3, Y4, Y5, Y6, and Y7and three outputs, i.e., A0, A1,and A2. This circuit has an enable input 'E'. Just like 2 to 4 line decoder, when enable 'E' is set to1, one of these four outputs will be 1.
IV. 1-TO-4 De-Multiplexer ( Using Standard Logic Gates )
V. 1-TO-4 De-Multiplexer Using the 74LS155ConclusionA multiplexer and a decoder can be used together to allow sharing of a data transmission line bya number of signals. Decoders are simply a collection of logic gates which are arranged in aspecific way so as to breakdown any combination of inputs to a set of terms that are all set to '0'apart from one term. A demultiplexer is used to connect a single source to multiple destinations.
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Term
Fall
Professor
N/A
Tags
Input output, Cybernetics, Digital circuits, input lines

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