Question

Design a modified priority encoder that receives an 8-bit input, A7:0and produces a 3-bit output, Y2:0. Y indicates the most significant bit of the input that is TRUE. Y should be 0 if none of the inputs are TRUE. Give a simplified Boolean equation, sketch a schematic, and write anHDL code

Answer 1

Answer:

Explanation:

The first image that I attached to this solution is the diagram of a truth table for an 8 to 3 bit encoder.

The second image  gives a sketch of the schematic.

The Boolean expression for the priority encoder including its zero inputs is defined in the third image attached.

Below is a snippet of the code for an 8 to 3 bit Priority encoder:

library IEEE;

use IEEE.STD_LOGIC_1164.all;

entity encoder8_3 is

   port(

       din : in STD_LOGIC_VECTOR(7 downto 0);

       dout : out STD_LOGIC_VECTOR(2 downto 0)

        );

end encoder8_3;

architecture encoder8_3_arc of encoder8_3 is

begin

   dout <= "000" when (din="10000000") else

           "001" when (din="01000000") else

           "010" when (din="00100000") else

           "011" when (din="00010000") else

           "100" when (din="00001000") else

           "101" when (din="00000100") else

           "110" when (din="00000010") else

           "111";

end encoder8_3_arc;