Skip to content

Files

Latest commit

77deda1 · Oct 23, 2022

History

History

Priority Encoder

Folders and files

NameName
Last commit message
Last commit date

parent directory

..
Sep 29, 2022
Sep 29, 2022
Oct 23, 2022

README.md

Priority Encoder

Introduction

A priority encoder is a circuit or algorithm that compresses multiple binary inputs into a smaller number of outputs. The output of a priority encoder is the binary representation of the index of the most significant activated line, starting from zero. They are often used to control interrupt requests by acting on the highest priority interrupt input.

A 4 to 2 priority encoder has 4 inputs : Y3, Y2, Y1 & Y0 and 2 outputs : A1 & A0. Here, the input, Y3 has the highest priority, whereas the input, Y0 has the lowest priority. In this case, even if more than one input is ‘1’ at the same time, the output will be the (binary) code corresponding to the input, which is having higher priority.

Truth Table

Inputs Outputs
Y3 Y2 Y1 Y0 A1 A0
0 0 0 0 x x
0 0 0 1 0 0
0 0 1 x 0 1
0 1 x x 1 0
1 x x x 1 1

From the above truth table we can infer that:

  • A0 is
    assign A0 = Y2(bar).Y1+Y3;
  • A1 is
    assign A1 = Y2+Y3;

Schematic of priority encoder

Encoder-4x2

IMAGE SOURCE - GFG

Realization of priority encoder

Realization

IMAGE SOURCE - Wikipedia