cnt25s.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 CNT25S IS
   PORT(CLK,EN25:IN STD_LOGIC;
DOUT25M,DOUT25B:OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END CNT25S;
ARCHITECTURE art OF CNT25S IS
SIGNAL CNT5B:STD_LOGIC_VECTOR(4 DOWNTO 0);
BEGIN
PROCESS(CLK,EN25)IS
  BEGIN
  
  IF(CLK'EVENT AND CLK='1')THEN
    IF CNT5B="11000"THEN
        CNT5B<="00000";
    ELSIF EN25='1' THEN 
        CNT5B<=CNT5B+1;
    ELSIF EN25='0'THEN
         CNT5B<=CNT5B-CNT5B-1;       
    END IF;
  END IF;
END PROCESS;
PROCESS(CNT5B)IS
BEGIN
CASE CNT5B IS
WHEN "00000"=>DOUT25B<="00100101";DOUT25M<="00110000";
WHEN "00001"=>DOUT25B<="00100100";DOUT25M<="00101001";
WHEN "00010"=>DOUT25B<="00100011";DOUT25M<="00101000";
WHEN "00011"=>DOUT25B<="00100010";DOUT25M<="00100111";
WHEN "00100"=>DOUT25B<="00100001";DOUT25M<="00100110";
WHEN "00101"=>DOUT25B<="00100000";DOUT25M<="00100101";
WHEN "00110"=>DOUT25B<="00011001";DOUT25M<="00100100";
WHEN "00111"=>DOUT25B<="00011000";DOUT25M<="00100011";
WHEN "01000"=>DOUT25B<="00010111";DOUT25M<="00100010";
WHEN "01001"=>DOUT25B<="00010110";DOUT25M<="00100001";
WHEN "01010"=>DOUT25B<="00010101";DOUT25M<="00100000";
WHEN "01011"=>DOUT25B<="00010100";DOUT25M<="00011001";
WHEN "01100"=>DOUT25B<="00010011";DOUT25M<="00011000";
WHEN "01101"=>DOUT25B<="00010010";DOUT25M<="00010111";
WHEN "01110"=>DOUT25B<="00010001";DOUT25M<="00010110";
WHEN "01111"=>DOUT25B<="00010000";DOUT25M<="00010101";
WHEN "10000"=>DOUT25B<="00001001";DOUT25M<="00010100";
WHEN "10001"=>DOUT25B<="00001000";DOUT25M<="00010011";
WHEN "10010"=>DOUT25B<="00000111";DOUT25M<="00010010";
WHEN "10011"=>DOUT25B<="00000110";DOUT25M<="00010001";
WHEN "10100"=>DOUT25B<="00000101";DOUT25M<="00010000";
WHEN "10101"=>DOUT25B<="00000100";DOUT25M<="00001001";
WHEN "10110"=>DOUT25B<="00000011";DOUT25M<="00001000";
WHEN "10111"=>DOUT25B<="00000010";DOUT25M<="00000111";
WHEN "11000"=>DOUT25B<="00000001";DOUT25M<="00000110";
WHEN OTHERS=>DOUT25B<="00000000";DOUT25M<="00000000";
END CASE;
END PROCESS;
END art;