fpga驱动led动态显示.txt

本压缩文件包含：使用VHDL来实现对LED的静态显示

--功能：动态扫描模块，位选信号高电平有效;
ieee library;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
entity fpgaqudongleddongtai is
       port(clk:in std_logic;
            reset:in std_logic;
            din1:in std_logic_vector(6 downto 0);
            din2:in std_logic_vector(6 downto 0);
            din3:in std_logic_vector(6 downto 0);
            din4:in std_logic_vector(6 downto 0);
            shift:out std_logic_vector(3 downto 0);
            bus4:out std_logic_vecotor(6 downto 0));
end;
architecture behave of fpgaqudongleddongtai is 
       signal scan_clk:std_logic_vector(1 downto 0);--jizhuzaijiegoutizhixia
       begin
         process(clk,scan_clk,reset)
         variable scan:std_logic_vector(17 downto 0);--jizhuzaijinchengzhixia
         begin
           if reset='1' then 
               scan:="000000000000000000";
               scan_clk<="00";
           elsif  clk'event and clk='1' then 
               scan:=scan+1;
           end if ;
           scan_clk<=scan(17 downt0 16);
         end process;
         begin
         case scan_clk is 
           when "00"=>
                bus4<=din1;
                shift<="0001";
           when "01"=>
                bus4<=din2;
                shift<="0010";
           when "10"=>
                bus4<=din3;
                shift<="0100";
           when "11"=>
                bus4<=din4;
                shift<="1000";
           when others=> bus4<="0000000";shift<="0000";
           end case ;
           end process;
end;