3-8
译码器的
VHDL
设计
1.
实体框图

2.
程序设计
正确的程?/p>
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
ENTITY DECODER38A IS
PORT(A2,A1,A0,S1,S2,S3:IN STD_LOGIC;
Y:OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END ENTITY DECODER38A;
ARCHITECTURE ONE OF DECODER38A IS
SIGNAL S: STD_LOGIC_VECTOR(5 DOWNTO 0);
BEGIN
S<=A2&A1&A0&S1&S2&S3;
WITH S SELECT
Y<="11111110" WHEN "000100",
"11111101" WHEN "001100",
"11111011" WHEN "010100",
"11110111" WHEN "011100",
"11101111" WHEN "100100",
"11011111" WHEN "101100",
"10111111" WHEN "110100",