led1.vhd

控制灯的各种工作方式

LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
ENTITY LED IS
PORT(CLK4HZ:IN STD_LOGIC;
      BUTTEN:IN STD_LOGIC;
       LED:OUT STD_LOGIC_VECTOR(3 DOWNTO 0));
END ENTITY LED;

ARCHITECTURE ONE OF LED IS
SIGNAL B:STD_LOGIC_VECTOR(1 DOWNTO 0);
SIGNAL C:STD_LOGIC_VECTOR(2 DOWNTO 0);
SIGNAL SEL:STD_LOGIC_VECTOR(1 DOWNTO 0);
BEGIN

BUTTEN_JISHU:PROCESS(BUTTEN)
             BEGIN
                IF FALLING_EDGE(BUTTEN) THEN
                   SEL<=SEL+1;
                 END IF;
             END PROCESS BUTTEN_JISHU;

MAICHONG_JISHU:PROCESS(CLK4HZ)
             BEGIN
                  
                IF RISING_EDGE(CLK4HZ) THEN
                   B<=B+1;C<=C+1;
                IF C=5 THEN
                  C<="000";               
                END IF;
                END IF;
                END PROCESS MAICHONG_JISHU;

                
STYLE:PROCESS(B,C,SEL)
         BEGIN
         IF (SEL="00") THEN
          CASE  B IS
             WHEN "00" => LED<="1110";
             WHEN "01" => LED<="1101";
             WHEN "10" => LED<="1011";
             WHEN "11" => LED<="0111";
            END CASE;
         
         

         
      ELSIF (SEL="01") THEN
           CASE B IS
             WHEN "00" => LED<="0111";
             WHEN "01" => LED<="1011";
             WHEN "10" => LED<="1101";
             WHEN "11" => LED<="1110";
            END CASE;
          
          

         
         ELSIF(SEL="10") THEN
           CASE C IS
             WHEN "000" => LED<="1110";
             WHEN "001" => LED<="1101";
             WHEN "010" => LED<="1011";
             WHEN "011" => LED<="0111";
             WHEN "100" => LED<="1011";
             WHEN "101" => LED<="1101";
             WHEN OTHERS =>NULL;
            END CASE;
         
         

      ELSIF (SEL="11") THEN
           CASE C IS
             WHEN "000" => LED<="0111";
             WHEN "001" => LED<="0011";
             WHEN "010" => LED<="0001";
             WHEN "011" => LED<="0000";
             WHEN "100" => LED<="0001";
             WHEN "101" => LED<="0011";
             WHEN OTHERS =>NULL;
            END CASE;
           
         END IF;
         END PROCESS STYLE;
END ARCHITECTURE ONE;