本人初学VHDL时编的比较系统的VHDL源程序 巨实用

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

entity occur is
    port (
        line: in STD_LOGIC_VECTOR (3 downto 0);
        row: buffer STD_LOGIC_VECTOR (3 downto 0);
        bcdout: out std_logic_vector ( 6 downto 0);
        dec3to8: out std_logic_vector ( 7 downto 0);
        clk: in STD_LOGIC;
        r: in STD_LOGIC
        );
end occur;

architecture occur_arch of occur is

signal dd:STD_LOGIC_VECTOR (1 downto 0);
signal dd1:STD_LOGIC_VECTOR (1 downto 0);
signal dcout3:STD_LOGIC_VECTOR (2 downto 0);
signal bcd:STD_LOGIC_VECTOR (3 downto 0);
signal line1:STD_LOGIC_VECTOR (1 downto 0);
signal cc:STD_LOGIC_VECTOR (3 downto 0);

signal cd1:STD_LOGIC_VECTOR (7 downto 0);
signal cd2:STD_LOGIC_VECTOR (7 downto 0);
signal cd3:STD_LOGIC_VECTOR (7 downto 0);
signal cd4:STD_LOGIC_VECTOR (7 downto 0);
signal cd:STD_LOGIC_VECTOR (7 downto 0);

signal keydown:std_logic;

signal  cout1:STD_LOGIC_VECTOR (3 downto 0);
signal  cout2:STD_LOGIC_VECTOR (3 downto 0);
signal  cout3:STD_LOGIC_VECTOR (3 downto 0);      
signal  cout4:STD_LOGIC_VECTOR (3 downto 0);      
signal  cout5:STD_LOGIC_VECTOR (3 downto 0);     

begin
	count: process (r, clk  )
	begin
	if ( r='1' ) then dd<="00";
	elsif( clk'event and clk = '1') then
			dd <= dd + '1';
			end if ;
	end process count ;
 	with dd select
   		row<="0111"when"00",
     		"1011"when"01",
     		"1101"when"10",
     		"1110"when"11",
     		"ZZZZ"when others ;

	with row select
   	  	dd1<= "00"when"0111",
     		"01"when"1011",
     		"10"when"1101",
     		"11"when"1110",
     		"ZZ"when others ;
   
	keydown<= line(0) and line(1) and line(2) and line(3) ;

	with line select
  		line1<="00"when"0111",
  		"01"when"1011",
     		"10"when"1101",
     		"11"when"1110",
     		"ZZ"when others ;

	process ( keydown,clk,r  )
	begin
		if ( r='1' ) then cc<="0000";
			elsif( clk'event and clk = '1') then
   				if (keydown = '0') then
      				cc <= dd1&line1 ;
    				end if;
		end if;
	end process ;




 
  process (cc)
        variable tmp: STD_LOGIC_VECTOR (7 downto 0);        
    begin
        tmp:="00000000";
        if (cc(3)='1') then
            tmp:=tmp+cc;
        end if;
        tmp:=tmp(6 downto 0) & '0';
        if (cc(2)='1') then
            tmp:=tmp+cc;
        end if;
        tmp:=tmp(6 downto 0) & '0';
        if (cc(1)='1') then
            tmp:=tmp+cc;
        end if;
        tmp:=tmp(6 downto 0) & '0';
        if (cc(0)='1') then
            tmp:=tmp+cc;
        end if;
        cd<=tmp;
    end process; 	
 	    --------------------- 4 bin => 2 BCD ------------------
    process (cc)
    begin
        if (cc>9) then 
            cout1<="0001";
            cout2<=cc+6;
        else
            cout1<="1111";
            cout2<=cc;
        end if;
    end process;    
    --------------------- 8 bin => 3 BCD ------------------
    process (cd)
    begin
        if (cd=0) then
            cout3<="1111";
            cout4<="1111";
            cout5<="0000";
        elsif (cd=1) then
            cout3<="1111";
            cout4<="1111";
            cout5<="0001";        
        elsif (cd=4) then
            cout3<="1111";
            cout4<="1111";
            cout5<="0100";        
        elsif (cd=9) then
            cout3<="1111";
            cout4<="1111";
            cout5<="1001";        
        elsif (cd=16) then
            cout3<="1111";
            cout4<="0001";
            cout5<="0110";        
        elsif (cd=25) then
            cout3<="1111";
            cout4<="0010";
            cout5<="0101";        
        elsif (cd=36) then
            cout3<="1111";
            cout4<="0011";
            cout5<="0110";        
        elsif (cd=49) then
            cout3<="1111";
            cout4<="0100";
            cout5<="1001";        
        elsif (cd=64) then
            cout3<="1111";
            cout4<="0110";
            cout5<="0100";        
        elsif (cd=81) then
            cout3<="1111";
            cout4<="1000";
            cout5<="0001";        
        elsif (cd=100) then
            cout3<="0001";
            cout4<="0000";
            cout5<="0000";        
        elsif (cd=121) then
            cout3<="0001";
            cout4<="0010";
            cout5<="0001";        
        elsif (cd=144) then
            cout3<="0001";
            cout4<="0100";
            cout5<="0100";        
        elsif (cd=169) then
            cout3<="0001";
            cout4<="0110";
            cout5<="1001";        
        elsif (cd=196) then
            cout3<="0001";
            cout4<="1001";
            cout5<="0110";        
        elsif (cd=225) then
            cout3<="0010";
            cout4<="0010";
            cout5<="0101";
        else        
            cout3<="1111";
            cout4<="1111";
            cout5<="1111";
        end if;
    end process;  
 	        
	count1: process (r, clk  )
		begin
		if ( r='1' ) then dcout3<="000";
			elsif( clk'event and clk = '1') then
				dcout3 <= dcout3 + '1';
		end if ;
	end process count1 ; 

 	with dcout3 select
  		bcd<=cout1 when"000",
     		cout2 when"001",
     		
     		cout3 when"101",
     		cout4 when"110",
     		cout5 when"111",
     		"1111"when others ; 

 	with bcd select
       		bcdout<="1111110"when "0000",
             		"0110000"when "0001",
             		"1101101"when "0010",
             		"1111001"when "0011",
             		"0110011"when "0100",
             		"1011011"when "0101",
             		"1011111"when "0110",
             		"1110000"when "0111",
             		"1111111"when "1000",
             		"1111011"when "1001",
             		"0000000"when others ;
  	  with dcout3 select
        dec3to8<="10000000" when "000",
           "01000000" when "001",
           "00100000" when "010",
           "00010000" when "011",
           "00001000" when "100",
           "00000100" when "101",
           "00000010" when "110",
           "00000001" when "111",
           "00000000" when others;
end occur_arch;