frame.vhd

用于视频运动图像编码的HUFFMAN编码

---------      电子系                 学号：J02301                姓名：张宗旺----
library ieee;
	use ieee.std_logic_1164.all;
	use ieee.std_logic_unsigned.all;

entity FRAME_DETECTOR is
	port(	RST,CLK,INPUT: 	in std_logic;
		OUTPUT:		out std_logic	);
end FRAME_DETECTOR;

architecture ALG of FRAME_DETECTOR is

	type STATES is (S0,S1,S2,S3,S4);
	signal CURRENT_STATE,NEXT_STATE:STATES;

begin
	
	COMPUTE_STATE:	process(INPUT,CURRENT_STATE)
	begin
		 	NEXT_STATE<=CURRENT_STATE;
			case CURRENT_STATE is
				when S0 => 
				if INPUT='0' then 
					NEXT_STATE<=S1;OUTPUT<='0';
				else
					NEXT_STATE<=S0;OUTPUT<='0';
				end if;
				when S1 => 
				if INPUT='1' then 
					NEXT_STATE<=S2;OUTPUT<='0';
				else
					NEXT_STATE<=S1;OUTPUT<='0';
				end if;
				when S2 => 
				if INPUT='0' then 
					NEXT_STATE<=S3;OUTPUT<='0';
				else
					NEXT_STATE<=S0;OUTPUT<='0';
				end if;
				when S3 => 
				if INPUT='1' then 
					NEXT_STATE<=S4;OUTPUT<='0';
				else
					NEXT_STATE<=S1;OUTPUT<='0';
				end if;
				when S4 => 
				if INPUT='1' then 
					NEXT_STATE<=S0;OUTPUT<='1';
				else
					NEXT_STATE<=S1;OUTPUT<='0';
				end if;
			end case;
	end process;
	
	UPDATA:		process(RST,CLK	)
	
	begin
		if RST='0' then
			CURRENT_STATE<=S0;
		elsif CLK'event and CLK='1' then
			CURRENT_STATE<=NEXT_STATE;
		end if;
	end process;	
end ALG;