cnt05s.vhd

课程设计《交通灯控制的设计》

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY CNT05S IS
   PORT(CLK,EN05M,EN05B:IN STD_LOGIC;
DOUT5:OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END CNT05S;
ARCHITECTURE art OF CNT05S IS
   SIGNAL CNT3B:STD_LOGIC_VECTOR(2 DOWNTO 0);
   BEGIN
   PROCESS(CLK,EN05M,EN05B)IS
     BEGIN
     IF CLK'EVENT AND CLK='1'THEN
        IF CNT3B="100"THEN
         CNT3B<="000";
        ELSIF EN05M='1'OR EN05B='1'THEN 
           CNT3B<=CNT3B+1;
        ELSE
           CNT3B<=CNT3B-CNT3B-1;
        END IF;
     END IF;
  END PROCESS;
  PROCESS(CNT3B)IS
    BEGIN
    CASE CNT3B IS
    WHEN "000"=>DOUT5<="00000101";
    WHEN "001"=>DOUT5<="00000100"; 
    WHEN "010"=>DOUT5<="00000011";
    WHEN "011"=>DOUT5<="00000010";
    WHEN "100"=>DOUT5<="00000001";
    WHEN OTHERS=>DOUT5<= "00000000";
    END CASE;
  END PROCESS;
END art;