基于BASYS2的VHDL程序——数字钟（改进版）

扩展到时分秒。加了入调时电路，但不知道为什么有两个按键不好使。而且不知道以何种方式假如按键消抖电路，因为加入后会多个时钟控制一个信号，物理不可实现。调试电路待解决。还有，四个数目管中间的那两个圆点怎么点亮啊，没有地址啊，求破。待我清明之后解决这个问题。

下面是代码。

 library IEEE;
 use IEEE.STD_LOGIC_1164.ALL;
 use IEEE.STD_LOGIC_ARITH.ALL;
 use IEEE.STD_LOGIC_UNSIGNED.ALL;

 entity clock is
     Port ( clk : in  STD_LOGIC;
               sw0:  in STD_LOGIC;
               btn : in  STD_LOGIC_VECTOR ( downto );
               led0:  out STD_LOGIC;
            seg : out  STD_LOGIC_VECTOR ( downto );
               seg7:out STD_LOGIC;
            an : out  STD_LOGIC_VECTOR ( downto ));
 end clock;

 architecture Behavioral of clock is
 signal num:STD_LOGIC_VECTOR ( downto );
 signal hour_h:STD_LOGIC_VECTOR ( downto );
 signal hour_l:STD_LOGIC_VECTOR ( downto );
 signal min_h:STD_LOGIC_VECTOR ( downto );
 signal min_l:STD_LOGIC_VECTOR ( downto );
 signal second_h:STD_LOGIC_VECTOR ( downto );
 signal second_l:STD_LOGIC_VECTOR ( downto );
 signal an_sel:STD_LOGIC_VECTOR ( downto );
 signal cnt:   INTEGER;
 signal cnt2:  INTEGER;
 signal sclk: STD_LOGIC;
 signal aclk: STD_LOGIC;
 signal shine:STD_LOGIC;
 begin
 led0<=shine;
 process(clk)
 begin
 if(clk'event and clk='') then
     if(cnt=) then
         cnt<=;
         sclk<=not sclk;
     else
         cnt<=cnt+;
     end if;
 end if;
 end process;

 process(clk)
 begin
 if(clk'event and clk='') then
     if(cnt2=) then
         cnt2<=;
         if(an_sel="") then
             an_sel<="";
         else
             an_sel<=an_sel+'';
         end if;
     else
         cnt2<=cnt2+;
     end if;
 end if;
 end process;

 process(sclk,sw0,btn)
 begin
 if(sw0='')    then
     if(btn()='') then
             second_l<=second_l+'';
     end if;
     if(btn()='') then
             second_h<=second_h+'';
     end if;
     if(btn()='') then
             hour_l<=hour_l+'';
     end if;
     if(btn()='') then
             hour_h<=hour_h+'';
     end if;
 else
     if(sclk'event and sclk='') then
         shine<=second_l();
         if(second_h="" and second_l="") then
             second_h<="";
             second_l<="";
             min_l<=min_l+'';
             if(min_h="" and min_l="") then
                 min_h<="";
                 min_l<="";
                 hour_l<=hour_l+'';
                 if(hour_h="" and min_l="") then
                     hour_h<="";
                     hour_l<="";
                 elsif(hour_l="")then
                     hour_h<=hour_h+'';
                     hour_l<="";
                 end if;
             elsif(min_l="") then
                 min_h<=min_h+'';
                 min_l<="";
             end if;
         elsif(second_l="") then
             second_h<=second_h+'';
             second_l<="";
         else
             second_l<=second_l+'';
         end if;
     end if;
 end if;
 end process;

 process(an_sel,second_l,second_h,min_l,min_h,hour_l,hour_h)
 begin
 case an_sel is
 when ""=>an<="";num<=min_l;seg7<='';
 when ""=>an<="";num<=min_h;seg7<='';
 when ""=>an<="";num<=hour_l;seg7<='';
 when ""=>an<="";num<=hour_h;seg7<='';
 when others=>null;
 end case;
 case num  is
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when x""=>seg<=b"";
         when others=>null;
 end case;
 end process;
 end Behavioral;

约束文件

 NET "clk" LOC = "B8";
 NET "led0" LOC ="M5";
 NET "an<0>" LOC="K14";
 NET "an<1>" LOC="M13";
 NET "an<2>" LOC="J12";
 NET "an<3>" LOC="F12";
 NET "seg7" 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 "btn<0>" LOC = "G12";
 NET "btn<1>" LOC = "C11";
 NET "btn<2>" LOC = "M4";
 NET "btn<3>" LOC = "A7";
 NET "sw0"    LOC="P11";