conter8.vhd

在EDA软件上编程

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
ENTITY conter8 IS
  PORT(CLK,RST,EN : IN STD_LOGIC;
              CQ : OUT STD_LOGIC_VECTOR(31 DOWNTO 0);
             COUT : OUT STD_LOGIC );
END conter8;
ARCHITECTURE BEHAV OF conter8 IS
BEGIN
  PROCESS(CLK, RST, EN)
 VARIABLE CQI1 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI2 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI3 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI4 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI5 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI6 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI7 : STD_LOGIC_VECTOR(3 DOWNTO 0);
 VARIABLE CQI8 : STD_LOGIC_VECTOR(3 DOWNTO 0);
  BEGIN 
   IF RST = '1' THEN CQI1 := (OTHERS =>'0');CQI2 := (OTHERS =>'0');CQI3 := (OTHERS =>'0');CQI4 := (OTHERS =>'0');CQI5 := (OTHERS =>'0');CQI6 := (OTHERS =>'0');CQI7 := (OTHERS =>'0');CQI8 := (OTHERS =>'0');
     ELSIF CLK'EVENT AND CLK='1' THEN
      IF EN = '1' THEN
        IF CQI1 < 9 THEN CQI1 := CQI1 + 1 ;COUT <='0';
          ELSE CQI1 := (OTHERS =>'0');
           if cqi2 < 9 then CQI2 := CQI2 + 1 ;COUT <='0';
             ELSE CQI2 := (OTHERS =>'0');
              if cqi3 < 9 then CQI3 := CQI3 + 1 ;COUT <='0';
                ELSE CQI3 := (OTHERS =>'0');
                  if cqi4 < 9 then CQI4 := CQI4 + 1 ;COUT <='0';  
                    ELSE CQI4 := (OTHERS =>'0');
                     if cqi5 < 9 then CQI5 := CQI5 + 1 ;COUT <='0';  
                      ELSE CQI5 := (OTHERS =>'0');
                       if cqi6 < 9 then CQI6 := CQI6 + 1 ;COUT <='0';  
                        ELSE CQI6 := (OTHERS =>'0');
                         if cqi7 < 9 then CQI7 := CQI7 + 1 ;COUT <='0';  
                          ELSE CQI7 := (OTHERS =>'0');
                           if cqi8 < 9 then CQI8 := CQI8 + 1 ;COUT <='0';  
                              ELSE CQI8 := (OTHERS =>'0');COUT <= '1';
                           end if;
                         end if;
                       end if;
                     end if;
                 end if;
              end if;
           end if;
        END IF;
      END IF;
   END IF;
     CQ(3 DOWNTO 0) <= CQI1;
     CQ(7 DOWNTO 4) <= CQI2;
     CQ(11 DOWNTO 8) <= CQI3;
     CQ(15 DOWNTO 12) <= CQI4;
     CQ(19 DOWNTO 16) <= CQI5;
     CQ(23 DOWNTO 20) <= CQI6;
     CQ(27 DOWNTO 24) <= CQI7;
     CQ(31 DOWNTO 28) <= CQI8;
  END PROCESS;
END BEHAV;