zzq.vhd

来自「eda微波炉程序控制器 初学vhdl语言的控制程序设计」· VHDL 代码 · 共 31 行

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_ARITH.ALL;
ENTITY ZZQ IS
  PORT(DATA1 : IN STD_LOGIC_VECTOR(15 DOWNTO 0);
     LD_8888 : IN STD_LOGIC;
     LD_CLK  : IN STD_LOGIC;
     LD_DONE : IN STD_LOGIC;
     DATA2   : OUT STD_LOGIC_VECTOR(15 DOWNTO 0);
     LOAD    : OUT STD_LOGIC);
END ENTITY ZZQ;

ARCHITECTURE ART OF ZZQ IS
 BEGIN
 PROCESS(DATA1,LD_8888,LD_CLK,LD_DONE) IS
    CONSTANT ALL_8 : STD_LOGIC_VECTOR(15 DOWNTO 0):="1000100010001000";
    CONSTANT DONE  : STD_LOGIC_VECTOR(15 DOWNTO 0):="1010101111001101"; 
    VARIABLE TEMP  : STD_LOGIC_VECTOR(2 DOWNTO 0);
  BEGIN
   LOAD<=LD_8888 OR LD_DONE OR LD_CLK;
   TEMP:=LD_8888 & LD_DONE & LD_CLK;
  CASE TEMP IS
   WHEN "100" => DATA2<=ALL_8;	--LOAD_8888 =1
   WHEN "010" => DATA2<=DONE;	--LOAD_DONE 
   WHEN "001" => DATA2<=DATA1;	--LOAD_CLK
   WHEN OTHERS=> NULL;
  END CASE;
 END PROCESS;
END ARCHITECTURE ART;