state.vhd

用于视频运动图像编码的HUFFMAN编码

package TYPES is
	type STATES is (S0,S1,S2);
end package TYPES;


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

use work.MYfunction.all;
use work.types.all;


entity HT is
	port(	START,CLK,RESET,DREADY,EQU:in std_logic;
		BUSY,READY,LATCH1,LATCH2,SYNCH2,RESET1,RESET2,RD,LOAD:out std_logic			);
end HT;

architecture BEHAVIORAL of HT is
	
	
	signal CNT :std_logic_vector( 4 downto 0);
	signal CURRENT_STATE,NEXT_STATE:STATES;
	
	
begin
	
	STATE_TRANS:process(CURRENT_STATE,START,DREADY,EQU)
	begin
		case CURRENT_STATE is
			when S0 =>
				if START='1'  then
					NEXT_STATE<=S1;
				else
				end if;
			when S1 =>
				if  DREADY='1' then
					NEXT_STATE<=S2;
				elsif START='0' then
					NEXT_STATE<=S0; 
				end if;
			when S2 =>
				if EQU='1'  then
					NEXT_STATE<=S1;
				elsif START='0' then
					NEXT_STATE<=S0;
				end if;	
		end case;
	end process STATE_TRANS;
	
	UPDATE:process(RESET,CLK)
	begin
		if RESET='0' then
			CURRENT_STATE<=S0;
			
		elsif CLK'event and CLK='1' then
			CURRENT_STATE<=NEXT_STATE;
		end if;
	end process UPDATE;
	
	COUNT_P:process
	begin
		wait until CLK'event and CLK='1'; 
		case CURRENT_STATE is
			when S0 => CNT<="00000";
			when S1 => CNT<="00000";	
			when S2 =>
				
					if  CNT = "11111" then
						CNT<="00000";
					else 
						CNT<=CNT+1;
					end if;
				
					
			when others =>null;
		end case;
	end process COUNT_P;
	
	OUTPUT_P:process (CURRENT_STATE,CNT)
	begin
		case CURRENT_STATE is
			when S0 =>
				BUSY<='0';
				LATCH1<='0';
				LATCH2<='0';
				SYNCH2<='0';
				RESET1<='1';
				RESET2<='1';
				RD<='0';
				LOAD<='0';
			when S1 => 
				BUSY<='1';
				READY<='1';
				LATCH1<='0';
				LATCH2<='0';
				SYNCH2<='0';
				RESET1<='1';
				RESET2<='0';
				RD<='0';
				LOAD<='0';
			when S2 =>
				case CNT is
					when "00000" =>
						LATCH1<='1';
						LATCH2<='0';
						SYNCH2<='0';
						LOAD<='0';
					when "00001" =>
						LATCH1<='0';
						LATCH2<='1';
						SYNCH2<='0';
						LOAD<='1';
					when "00010" =>
						LATCH1<='0';
						LATCH2<='1';
						SYNCH2<='0';
						LOAD<='0';
					when "00011" =>
						LATCH1<='0';
						LATCH2<='0';
						SYNCH2<='0';
						LOAD<='0';	
				
					when others =>
					
						LATCH1<='0';
						LATCH2<='0';
						SYNCH2<='1';
						LOAD<='0';
				end case;
				RESET1<='0';
				RESET2<='1';
				RD<='1';
			when others => null;
		end case;
	end process OUTPUT_P;
			
						
end BEHAVIORAL;