display.vhd

测频器

--Author    	: 屈峥 2002081212
--File Name 	: DISPLAY.vhd
--Objective 	: 动态显示
--
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY DISPLAY IS
   PORT (A1 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A2 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A3 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A4 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A5 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A6 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A7 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         A8 : IN STD_LOGIC_VECTOR(3 DOWNTO 0);
         CLK : IN STD_LOGIC;
         KEY : OUT STD_LOGIC_VECTOR(2 DOWNTO 0);
         DISPLAYOUT : OUT STD_LOGIC_VECTOR(3 DOWNTO 0) );
  END DISPLAY;
ARCHITECTURE BEHAV OF DISPLAY IS
   SIGNAL CQI : STD_LOGIC_VECTOR(3 DOWNTO 0);
   SIGNAL COUTI : STD_LOGIC_VECTOR(2 DOWNTO 0);
  BEGIN
     PROCESS ( CLK )
        BEGIN
           IF CLK'EVENT AND CLK = '1' THEN
              IF COUTI < "111" THEN COUTI <= COUTI + 1;
                 ELSE COUTI <= (OTHERS => '0');
               END IF;    
           END IF;
           CASE COUTI IS
              WHEN "000" => CQI <= A1;
              WHEN "001" => CQI <= A2;
              WHEN "010" => CQI <= A3;
              WHEN "011" => CQI <= A4;
              WHEN "100" => CQI <= A5;
              WHEN "101" => CQI <= A6;
              WHEN "110" => CQI <= A7;
              WHEN "111" => CQI <= A8;
              WHEN OTHERS => NULL;
            END CASE;
           DISPLAYOUT <= CQI;
           KEY <= COUTI;
         END PROCESS;
 END;