ps2.vhd

vhdl 写得ps2 ipvhdl 写得ps2 ipvhdl 写得ps2 ip

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-- Company: 
-- Engineer: 
-- 
-- Create Date:    21:39:44 12/03/2007 
-- Design Name: 
-- Module Name:    PS2 - Behavioral 
-- Project Name: 
-- Target Devices: 
-- Tool versions: 
-- Description: 
--
-- Dependencies: 
--
-- Revision: 
-- Revision 0.01 - File Created
-- Additional Comments: 
--
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library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating
---- any Xilinx primitives in this code.
--library UNISIM;
--use UNISIM.VComponents.all;

entity PS2 is
    Port ( dclk : in  STD_LOGIC;
           datain : in  STD_LOGIC;
			  lcd_e : out  STD_LOGIC;
           lcd_rw : out  STD_LOGIC;
           lcd_rs : out  STD_LOGIC;
           sf_d : out  STD_LOGIC_VECTOR (3 downto 0);
           clk : in  STD_LOGIC);
end PS2;

architecture Behavioral of PS2 is

signal count : integer range 0 to 10 :=0;
signal lword1,lword2 : std_logic_vector(3 downto 0);
signal hword1,hword2 : std_logic_vector(3 downto 0);
signal state : integer range 0 to 7 := 0;
Type data is array (0 to 3, 0 to 1) of std_logic_vector(3 downto 0);
constant cmd : data := (("0010","1000"),--Function set
								  ("0000","0110"),--Entry mode set
								  ("0000","1100"),--Display on/off
								  ("1000","0000")--Set DDram address
								  );
signal index : integer range 0 to 4 :=0;
signal count0 : integer range 0 to 750000 := 0;
signal sflag : std_logic := '0';
signal flag : integer range 0 to 15 := 0;
signal twochar: std_logic :='0';

begin

process(clk)
begin

if rising_edge(clk) then
	if(state = 0) then --initializtion
		if(flag = 0) then
			if count0 = 750000 then
				flag <= 1;
				sf_d <= "0011";
				lcd_e <= '1';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 1 then
			if count0 = 12 then
				flag <= 2;
				lcd_e <= '0';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 2 then
			if count0 = 205000 then
				flag <= 3;
				sf_d <= "0011";
				lcd_e <= '1';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 3 then
			if count0 = 12 then
				flag <= 4;
				lcd_e <= '0';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 4 then
			if count0 = 5000 then
				flag <= 5;
				sf_d <= "0011";
				lcd_e <= '1';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;	
		elsif flag = 5 then
			if count0 = 12 then
				flag <= 6;
				lcd_e <= '0';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;	
		elsif flag = 6 then
			if count0 = 2000 then
				flag <= 7;
				sf_d <= "0010";
				lcd_e <= '1';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;	
		elsif flag = 7 then
			if count0 = 12 then
				flag <= 8;
				lcd_e <= '0';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;	
		else
			if count0 = 2000 then
				flag <= 0;
				count0 <= 0;
				state <= 1;
				lcd_rs <= '0';
				lcd_rw <= '0';
				sf_d <= cmd(index,0);--the high 4bits
			else
				count0 <= count0+1;
			end if;				
		end if;
		
	elsif state = 1 then	--send command
		if flag = 0 then	   --delay 40ns
			if count0 = 2 then
				flag <= 1;
				count0 <= 0;
				lcd_e <= '1';   
			else
				count0 <= count0+1;
			end if;
		elsif flag = 1 then  --delay 230ns
			if count0 = 12 then
				flag <= 2;
				lcd_e <= '0';
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 2 then --delay 20ns
			if count0 = 1 then
				if sflag = '0' then --the word is not finished					
					flag <= 3;
				else
					flag <= 4; 
				end if;
				lcd_rw <= '1';
				count0 <= 0;				
			else
				count0 <= count0+1;
			end if;
		elsif flag = 3 then --delay 1us,low 4bits
			if count0 = 50 then
				sflag <= '1';
				flag <= 0;
				lcd_rw <= '0';
				count0 <= 0;
				sf_d <= cmd(index,1);
				index <= index+1;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 4 then --delay 40us, the word is finished
			if count0 = 2000 then
				sflag <= '0';
				flag <= 0;
				lcd_rw <= '0';
				count0 <= 0;
				if index = 4 then
					lcd_rs <= '1';
					state <= 2;
				else
					sf_d <= cmd(index,0);
				end if;
			else
				count0 <= count0+1;
			end if;
		end if;
		
	elsif state = 2 then --read data
		if dclk = '0' then --transfer start
			if twochar = '0' then --character				
				if count=9 then --parity check 
					case hword1&lword1 is
						when "00011100"=>hword1<="0110";lword1<="0001";--a
						when "00110010"=>hword1<="0110";lword1<="0010";--b
						when "00100001"=>hword1<="0110";lword1<="0011";--c
						when "00100011"=>hword1<="0110";lword1<="0100";--d
						when "00100100"=>hword1<="0110";lword1<="0101";--e
						when "00101011"=>hword1<="0110";lword1<="0110";--f
						when "00110100"=>hword1<="0110";lword1<="0111";--g
						when others=>hword1<="1111";lword1<="0000";
					end case;
					state <= 3;	
				elsif count=11 then --transfer finished
					sf_d <= hword1;
					twochar <= '1';
					count <= 0;
					state <= 3;	
				elsif (count>0 and count<5) then--low 4bits
					lword1(count-1) <= datain;
					state <= 3;	
				elsif (count>4 and count<9) then --high 4bits
					hword1(count-5) <= datain;
					state <= 3;	
				else
					state <= 3;	
				end if;	
			else  
				if count=11 then
					if ( lword2="0000" and hword2="1111") then
						twochar <= '0';
						state <= 4;
					else
						state <= 3;	
					end if;
					count <= 0;					
				elsif (count>0 and count<5) then
					lword2(count-1) <= datain;
					state <= 3;	
				elsif (count>4 and count<9) then --high 4bits
					hword2(count-5) <= datain;
					state <= 3;	
				else 
					state <= 3;	
				end if;
			end if;			
		end if;
	
	elsif state = 3 then --read next bit
			if count0 = 4000 then --delay 80us
				count <= count+1;
				state <= 2;
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
			
	elsif state = 4 then --send characters
		if flag = 0 then	   --delay 40ns
			if count0 = 2 then
				flag <= 1;
				count0 <= 0;
				lcd_e <= '1';
			else
				count0 <= count0+1;
			end if;
		elsif flag = 1 then  --delay 230ns
			if count0 = 12 then
				flag <= 2;
				lcd_e <= '0';
				count0 <= 0;
			else
				count0 <= count0+1;
				end if;
		elsif flag = 2 then --delay 20ns
			if count0 = 1 then
				if sflag = '0' then --the word is not finished				
					flag <= 3;
				else
					flag <= 4; 
				end if;
				lcd_rw <= '1';
				count0 <= 0;				
			else
				count0 <= count0+1;
			end if;
		elsif flag = 3 then --delay 1us,low 4bits
			if count0 = 50 then
				sflag <= '1';
				flag <= 0;
				lcd_rw <= '0';
				count0 <= 0;
				sf_d <= lword1 ;
			else
				count0 <= count0+1;
			end if;
		elsif flag = 4 then --delay 40us
			if count0 = 2000 then
				sflag <= '0';
				flag <= 0;
				lcd_rw <= '0';
				state <= 2;
				count0 <= 0;
			else
				count0 <= count0+1;
			end if;
		end if;		
	end if;
	
end if;

end process;

end Behavioral;