基于BASYS2的VHDL程序——交通灯

请尊重作者版权，转载请注明原地址： http://www.cnblogs.com/connorzx/p/3676746.html 

数电实验交通灯VHDL版，程序写的扩展性很差，待以后有时间进行优化。

程序如下：

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity main is
    Port ( clk : in  STD_LOGIC;
           rst : in  STD_LOGIC;
           led : out  STD_LOGIC_VECTOR (5 downto 0);
           an : out  STD_LOGIC_VECTOR (3 downto 0);
           seg : out  STD_LOGIC_VECTOR (6 downto 0));
end main;

architecture Behavioral of main is
signal sclk: std_logic;
signal cnt0:integer:=0;
signal cnt1:integer:=0;
signal cnt2:integer:=0;
signal cnt3:integer:=0;
signal disp1:integer:=0;
signal disp2:integer:=3;
signal display:integer;
signal num1:integer;
signal num1_l:integer;
signal num1_h:integer;
signal num2:integer;
signal num2_l:integer;
signal num2_h:integer;
signal ledt: std_logic_vector (5 downto 0);
signal an_sel: integer;
begin
led(0)<=ledt(0);
led(1)<=ledt(1);
led(2)<=ledt(2);
led(3)<=ledt(3);
led(4)<=ledt(4);
led(5)<=ledt(5);
process(clk)
begin
    if(clk'event and clk='1') then
        if(cnt0=25000000)then
            cnt0<=0;
            sclk<=not sclk;
        else
            cnt0<=cnt0+1;
        end if;
    end if;
end process;

process(clk)
begin
if(clk'event and clk='1') then
    if(cnt2=50000) then
        cnt2<=0;
          if(an_sel=3)then
                an_sel<=0;
          else
                an_sel<=an_sel+1;
          end if;
    else
        cnt2<=cnt2+1;
    end if;
end if;
end process;

process(rst,sclk)
begin
    if(rst='1') then
            ledt(0)<='0';
            ledt(1)<='0';
            ledt(2)<='0';
    elsif(sclk'event and sclk='1') then
        cnt1<=cnt1+1;
        cnt3<=cnt3+1;
        if(cnt1>=1 and cnt1<=16)then
            ledt(0)<='1';
            ledt(1)<='0';
            ledt(2)<='0';
        elsif(cnt1>=17 and cnt1<=29)then
            ledt(0)<='0';
            ledt(1)<='1';
            ledt(2)<='0';
        elsif(cnt1=30)then
            ledt(0)<='0';
            ledt(1)<='0';
            ledt(2)<='1';
        elsif(cnt1=31)then
            cnt1<=0;
        end if;
        if(cnt3>=1 and cnt3<=13)then
            ledt(3)<='0';
            ledt(4)<='1';
            ledt(5)<='0';
        elsif(cnt3>=14 and cnt3<=16)then
            ledt(3)<='0';
            ledt(4)<='0';
            ledt(5)<='1';
        elsif(cnt3=17)then
            ledt(3)<='1';
            ledt(4)<='0';
            ledt(5)<='0';
        elsif(cnt3=31)then
            cnt3<=0;
        end if;
    end if;
end process;

process(sclk,ledt,rst)
begin
if (rst='1')then
        disp1<=0;
        disp2<=3;
    elsif(sclk'event and sclk='1') then
        if(ledt(0)='1' or ledt(1)='1' or ledt(2)='1')then    
            if(ledt(0)='1' and disp1=15)then
                disp1<=3;
            elsif(ledt(1)='1' and disp1=15)then
                disp1<=13;
            elsif(ledt(2)='1' and disp1=15)then
                disp1<=0;
            else
                disp1<=disp1 + 1;
            end if;
        end if;
        if(ledt(3)='1' or ledt(4)='1' or ledt(5)='1')then    
            if(ledt(3)='1' and disp2=15)then
                disp2<=3;
            elsif(ledt(4)='1' and disp2=15)then
                disp2<=13;
            elsif(ledt(5)='1' and disp2=15)then
                disp2<=0;
            else
                disp2<=disp2 + 1;
            end if;
        end if;
    end if;
end process;

process(an_sel)
begin
    num1<=15-disp1;
    if(num1>=10)then
        num1_h<=1;
        num1_l<=num1-10;
    else
        num1_h<=0;
        num1_l<=num1;
    end if;
        num2<=15-disp2;
    if(num2>=10)then
        num2_h<=1;
        num2_l<=num2-10;
    else
        num2_h<=0;
        num2_l<=num2;
    end if;
case an_sel is
        when 0=>an<="1110";display<=num1_l;
        when 1=>an<="1101";display<=num1_h;
        when 2=>an<="1011";display<=num2_l;
        when 3=>an<="0111";display<=num2_h;
        when others=>null;
end case;
case display is
          when 0=>seg<=b"0000001";
          when 1=>seg<=b"1001111";
          when 2=>seg<=b"0010010";
          when 3=>seg<=b"0000110";
          when 4=>seg<=b"1001100";
          when 5=>seg<=b"0100100";
          when 6=>seg<=b"0100000";
          when 7=>seg<=b"0001111";
          when 8=>seg<=b"0000000";
          when 9=>seg<=b"0000100";
          when others=>null;
end case;
end process;
end Behavioral;

约束文件

NET "clk" LOC = "B8";
NET "led<0>" LOC = "M5";
NET "led<1>" LOC = "M11";
NET "led<2>" LOC = "P7";
NET "led<3>" LOC = "P6";
NET "led<4>" LOC = "N5";
NET "led<5>" LOC = "N4";
NET "an<0>" LOC="F12";
NET "an<1>" LOC="J12";
NET "an<2>" LOC="M13";
NET "an<3>" LOC="K14";
#NET "seg<7>" LOC="N13";
NET "seg<6>" LOC="L14";
NET "seg<5>" LOC="H12";
NET "seg<4>" LOC="N14";
NET "seg<3>" LOC="N11";
NET "seg<2>" LOC="P12";
NET "seg<1>" LOC="L13";
NET "seg<0>" LOC="M12";  
NET "rst" LOC="P11";