keyboad.vhd

VHDL 的4*4键盘代码

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_arith.all;
entity keyboad is
   port(hang:out std_logic_vector(3 downto 0);
         wei:out std_logic_vector(2 downto 0);
         ma:out std_logic_vector(3 downto 0);
         lie:in std_logic_vector(3 downto 0);
         clk:in std_logic);
end keyboad;
architecture jiegou of keyboad is
  signal lie_in: std_logic_vector(3 downto 0);
  signal clk_a:std_logic:='0';
  signal temp_h,temp_l:integer range 3 downto 0 :=0;
   begin
wei<="000";
fenpin:process(clk)
       variable temp:integer range 19999 downto 0 :=0;
       begin
          if(clk'event and clk='1')then
             if(temp=19999)then
                 temp:=0;clk_a<=not clk_a;
                   else
                  temp:=temp+1;
              end if;
           end if;
         end process fenpin;
         
    g1:process(clk_a)
        begin
          if(clk_a'event and clk_a='1')then
                if(temp_h=3)then
                     temp_h<=0;
                    else
                     temp_h<=temp_h+1;
                 end if;
                  case temp_h is
                        when 0 =>hang<="0001";
                        when 1 =>hang<="0010";
                        when 2 =>hang<="0100";
                        when 3 =>hang<="1000";
                        when others =>hang<="XXXX";
                   end case;

          end if;
      end process g1;

    g2:process(lie)
         begin
         if(lie/="0000")then
               lie_in<=lie;
              case lie_in is
                    when "0001" =>temp_l<=0;
                    when "0010" =>temp_l<=1;
                    when "0100" =>temp_l<=2;
                    when "1000" =>temp_l<=3;
                    when others=>temp_l<=0;         
            end case;
              if(temp_h=0)then
                     if(temp_l=0)then
                          ma<="0000";
                      elsif(temp_l=1)then
                          ma<="0001";
                      elsif(temp_l=2)then
                          ma<="0010";
                      else
                          ma<="0011";
                       end if;
             elsif(temp_h=1)then
                     if(temp_l=0)then
                          ma<="0100";
                      elsif(temp_l=1)then
                          ma<="0101";
                      elsif(temp_l=2)then
                          ma<="0110";
                      else
                          ma<="0111";
                       end if;
             elsif(temp_h=2)then
                     if(temp_l=0)then
                          ma<="1000";
                      elsif(temp_l=1)then
                          ma<="1001";
                      elsif(temp_l=2)then
                          ma<="1010";
                      else
                          ma<="1011";
                       end if;

             elsif(temp_h=3)then
                     if(temp_l=0)then
                          ma<="1100";
                      elsif(temp_l=1)then
                          ma<="1101";
                      elsif(temp_l=2)then
                          ma<="1110";
                      else
                          ma<="1111";
                       end if;
              end if;
       end if;
end process g2;
end jiegou;