cnt25.vhd

这是本人在Max plus2环境下用VHDL语言编的交通灯控制程序。做EDA课程设计的朋友可以下来参考参考。

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.STD_LOGIC_UNSIGNED.ALL;
ENTITY CNT25 IS
PORT(SB,CLK,EN25:IN STD_LOGIC;
     DOUT25M,DOUT25B: OUT STD_LOGIC_VECTOR(7 DOWNTO 0));
END ENTITY CNT25;
ARCHITECTURE  one OF CNT25 IS
SIGNAL CNTB:STD_LOGIC_VECTOR(4 DOWNTO 0);
 BEGIN 
PROCESS(SB,CLK,EN25) IS
BEGIN
IF SB='0' THEN CNTB<=CNTB-CNTB-1;
 ELSIF (CLK'EVENT AND CLK='1') THEN
   IF EN25='1' THEN CNTB<=CNTB+1;
 ELSIF EN25='0' THEN CNTB<=CNTB-CNTB-1;
END IF;
END IF;
END PROCESS;
PROCESS(CNTB) IS 
BEGIN 
CASE CNTB IS
WHEN "00000"=>DOUT25M<="00100101";DOUT25B<="00110000";
WHEN "00001"=>DOUT25M<="00100100";DOUT25B<="00101001";
WHEN "00010"=>DOUT25M<="00100011";DOUT25B<="00101000";
WHEN "00011"=>DOUT25M<="00100010";DOUT25B<="00100111";
WHEN "00100"=>DOUT25M<="00100001";DOUT25B<="00100110";
WHEN "00101"=>DOUT25M<="00100000";DOUT25B<="00100101";
WHEN "00110"=>DOUT25M<="00011001";DOUT25B<="00100100";
WHEN "00111"=>DOUT25M<="00011000";DOUT25B<="00100011";
WHEN "01000"=>DOUT25M<="00010111";DOUT25B<="00100010";
WHEN "01001"=>DOUT25M<="00010110";DOUT25B<="00100001";
WHEN "01010"=>DOUT25M<="00010101";DOUT25B<="00100000";
WHEN "01011"=>DOUT25M<="00010100";DOUT25B<="00011001";
WHEN "01100"=>DOUT25M<="00010011";DOUT25B<="00011000";
WHEN "01101"=>DOUT25M<="00010010";DOUT25B<="00010111";
WHEN "01110"=>DOUT25M<="00010001";DOUT25B<="00010110";
WHEN "01111"=>DOUT25M<="00010000";DOUT25B<="00010101";
WHEN "10000"=>DOUT25M<="00001001";DOUT25B<="00010100";
WHEN "10001"=>DOUT25M<="00001000";DOUT25B<="00010011";
WHEN "10010"=>DOUT25M<="00000111";DOUT25B<="00010010";
WHEN "10011"=>DOUT25M<="00000110";DOUT25B<="00010001";
WHEN "10100"=>DOUT25M<="00000101";DOUT25B<="00010000";
WHEN "10101"=>DOUT25M<="00000100";DOUT25B<="00001001";
WHEN "10110"=>DOUT25M<="00000011";DOUT25B<="00001000";
WHEN "10111"=>DOUT25M<="00000010";DOUT25B<="00000111";
WHEN "11000"=>DOUT25M<="00000001";DOUT25B<="00000101";
WHEN OTHERS=>DOUT25M<="00000000";DOUT25B<="00000000";
END CASE;
END PROCESS;
END ARCHITECTURE one;