divd_fren.vhd

用VHDL实现的键盘扫描程序 可以稍微修改就可使用

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;


entity divd_fren is
   port(
         load:in std_logic;
         clk_in:in std_logic;
         start:in std_logic;
         stop: in std_logic;
         data_in_h:in std_logic_vector(7 downto 0);
         data_in_l:in std_logic_vector(7 downto 0);
         clk_out:out std_logic
        );
end divd_fren;

architecture a of divd_fren is
  signal flag:std_logic=0;
  signal temp_data_in_h:std_logic_vector(7 downto 0);
  signal temp_data_in_l:std_logic_vector(7 downto 0);
  signal temp_couter: std_logic_vector(7 downto 0);
  signal temp_couter1: std_logic_vector(7 downto 0);
   begin
    process(clk_in,start,stop,load)
    begin
     --temp_couter<=temp_couter;
    if(clk_in 'event and clk_in='1')then
       if(stop='1')then
        clk_out<='0';
       else if(load='1')then
         temp_data_in_h<=data_in_h;
         temp_data_in_l<=data_in_l;
         temp_couter<="00000000";
         temp_couter1<="00000000";
      end if;
     end if;
     if(start='1')then
      
        if(flag='1')then
          if(temp_couter/=temp_data_in_h)then
            temp_couter<=temp_couter+1;
            clk_out<='1';
            flag<='1';
          else 
            temp_couter<="00000000";
          --  temp_couter<="00000000";
            temp_couter1<="00000000";
            flag<='0';
           end if;
       else
          if(temp_couter1/=temp_data_in_l)then
            temp_couter1<=temp_couter1+1;
            clk_out<='0';
            flag<='0';
          else 
            temp_couter<="00000000";
            temp_couter1<="00000000";
            flag<='1';
          end if;     
       end if;
     end if;
   end if; 
 
--end if;  
end process;
end a;