display.vhd

这是一个在Quartus II软件中编写的vhdl程序。程序下载后可用蜂鸣器播放音乐

library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity display is
port(din0:in std_logic_vector(3 downto 0);
     din1:in std_logic_vector(3 downto 0);
     din2:in std_logic_vector(3 downto 0);
     din3:in std_logic_vector(3 downto 0);
     din4:in std_logic_vector(3 downto 0);
     din5:in std_logic_vector(3 downto 0);
     clk:in std_logic;
     led_sa:out std_logic;
     led_sb:out std_logic;
     led_sc:out std_logic;
     led_a:out std_logic;
     led_b:out std_logic;
     led_c:out std_logic;
     led_d:out std_logic;
     led_e:out std_logic;
     led_f:out std_logic;
     led_g:out std_logic;
     led_dp:out std_logic);
end entity;
architecture behav of display is
 signal seg:std_logic_vector(6 downto 0);
 signal sel:std_logic_vector(2 downto 0);
 signal num:std_logic_vector(3 downto 0);
 signal s:std_logic_vector(2 downto 0);
begin
  led_sa<=sel(0);
  led_sb<=sel(1);
  led_sc<=sel(2);
  led_a<=seg(0);
  led_b<=seg(1);
  led_c<=seg(2);
  led_d<=seg(3);
  led_e<=seg(4);
  led_f<=seg(5);
  led_g<=seg(6);
process(clk)
begin
  if clk'event and clk='1' then
    if s="101" then s<="000";
    else s<=s+'1';
    end if;
   end if;
end process;
process(s,din0,din1,din2,din3,din4,din5)
begin
  if s="000" then sel<="000";num<=din0;led_dp<='0';
 elsif s="001" then sel<="001";num<=din1;led_dp<='0';
 elsif s="010" then sel<="010";num<=din2;led_dp<='0';
 elsif s="011" then sel<="011";num<=din3;led_dp<='0';
 elsif s="100" then sel<="100";num<=din4;led_dp<='0';
 elsif s="101" then sel<="101";num<=din5;led_dp<='0';
 else sel<="XXX";num<="XXXX";led_dp<='0';
  end if;
end process;
 seg<="0111111"when num=0 else
  "0000110" when num=1 else
  "1011011" when num=2 else
  "1001111" when num=3 else
  "1100110" when num=4 else
  "1101101" when num=5 else
  "1111101" when num=6 else
  "0000111" when num=7 else
  "1111111" when num=8 else
  "1101111" when num=9 else
  "1110111" when num=10 else
  "1111100" when num=11 else
  "0111001" when num=12 else
  "1011110" when num=13 else
  "1111001" when num=14 else
  "1110001" when num=15 else 
  "0000000";
end behav;