key0.vhd

CPLD的小程序集合

--
-- 矩阵键盘实验1：向用户介绍矩阵键盘扫描实现的方法，没有考虑去抖和判断键弹起的问题；把相应的键值显示在数码管上
-- 
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

ENTITY key0 IS
   PORT (
      clk                     : IN std_logic;   
      rst                     : IN std_logic;   
      row                     : OUT std_logic_vector(3 DOWNTO 0); -- 行线 
      column                  : IN std_logic_vector(3 DOWNTO 0);  -- 列线
      dataout                 : OUT std_logic_vector(7 DOWNTO 0); -- 数码管显示数据 
      en                      : OUT std_logic_vector(7 DOWNTO 0)); --数码管显示使能  
END key0;

ARCHITECTURE arch OF key0 IS

SIGNAL div_cnt : std_logic_vector(24 downto 0);
SIGNAL scan_key                 :  std_logic_vector(3 DOWNTO 0); --扫描码寄存器  
SIGNAL key_code                 :  std_logic_vector(3 DOWNTO 0);   
SIGNAL dataout_tmp            :  std_logic_vector(7 DOWNTO 0);   
SIGNAL en_tmp                 :  std_logic_vector(7 DOWNTO 0);  
BEGIN
 row <= scan_key;
 dataout <= dataout_tmp;
 en <= en_tmp; 
 en_tmp<="00000000";

 PROCESS(clk,rst)
 BEGIN
      IF (NOT rst = '1') THEN
         div_cnt <= "0000000000000000000000000";    
      ELSIF(clk'EVENT AND clk = '1')THEN
         div_cnt <= div_cnt + 1;    
      END IF;
 END PROCESS;

 PROCESS(div_cnt(20 downto 19))
 BEGIN
    CASE div_cnt(20 downto 19) IS
    WHEN "00"=> scan_key<="1110";
    WHEN "01"=> scan_key<="1101";
    WHEN "10"=> scan_key<="1011";
    WHEN "11"=> scan_key<="0111";
    END CASE;
 END PROCESS;

 PROCESS(clk,rst)
   BEGIN
      
      IF (NOT rst = '1') THEN
         key_code <= "0000";    
      ELSIF(clk'EVENT AND clk='1')THEN
         CASE scan_key IS  --检测何处有键按下
            WHEN "1110" =>
                     CASE column IS
                        WHEN "1110" =>
                                 key_code  <= "0000";    
                        WHEN "1101" =>
                                 key_code  <= "0001";    
                        WHEN "1011" =>
                                 key_code  <= "0010";    
                        WHEN "0111" =>
                                 key_code  <= "0011";    
                        WHEN OTHERS =>
                                 NULL;
                        
                     END CASE;
            WHEN "1101" =>
                     CASE column IS
                        WHEN "1110" =>
                                 key_code  <= "0100";    
                        WHEN "1101" =>
                                 key_code  <= "0101";    
                        WHEN "1011" =>
                                 key_code  <= "0110";    
                        WHEN "0111" =>
                                 key_code  <= "0111";    
                        WHEN OTHERS =>
                                 NULL;
                        
                     END CASE;
            WHEN "1011" =>
                     CASE column IS
                        WHEN "1110" =>
                                 key_code  <= "1000";    
                        WHEN "1101" =>
                                 key_code  <= "1001";    
                        WHEN "1011" =>
                                 key_code  <= "1010";    
                        WHEN "0111" =>
                                 key_code  <= "1011";    
                        WHEN OTHERS =>
                                 NULL;
                        
                     END CASE;
            WHEN "0111" =>
                     CASE column IS
                        WHEN "1110" =>
                                 key_code  <= "1100";    
                        WHEN "1101" =>
                                 key_code  <= "1101";    
                        WHEN "1011" =>
                                 key_code  <= "1110";    
                        WHEN "0111" =>
                                 key_code  <= "1111";    
                        WHEN OTHERS =>
                                 NULL;
                        
                     END CASE;
            WHEN OTHERS  =>
                     key_code  <= "1111";    
            
         END CASE;
      END IF;
   END PROCESS;

-----显示键值
PROCESS(key_code)
   BEGIN
      CASE key_code IS
         WHEN "0000" =>
                  dataout_tmp <= "11000000";    
         WHEN "0001" =>
                  dataout_tmp <= "11111001";    
         WHEN "0010" =>
                  dataout_tmp <= "10100100";    
         WHEN "0011" =>
                  dataout_tmp <= "10110000";    
         WHEN "0100" =>
                  dataout_tmp <= "10011001";    
         WHEN "0101" =>
                  dataout_tmp <= "10010010";    
         WHEN "0110" =>
                  dataout_tmp <= "10000010";    
         WHEN "0111" =>
                  dataout_tmp <= "11111000";    
         WHEN "1000" =>
                  dataout_tmp <= "10000000";    
         WHEN "1001" =>
                  dataout_tmp <= "10011000";    
         WHEN "1010" =>
                  dataout_tmp <= "00010001";    
         WHEN "1011" =>
                  dataout_tmp <= "11000001";    
         WHEN "1100" =>
                  dataout_tmp <= "01100011";    
         WHEN "1101" =>
                  dataout_tmp <= "10000101";    
         WHEN "1110" =>
                  dataout_tmp <= "01100001";    
         WHEN "1111" =>
                  dataout_tmp <= "01110001";    
         WHEN OTHERS =>
                  NULL;
         
      END CASE;
   END PROCESS;
END arch;