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1. 实验内容

FIFO实验与仿真验证。

2. 实验步骤

（1） 新建工程

3. 实验结果

（1） 仿真激励

rst <= '0';		write_en <= '1';	wait for clk_period;rst <= '1';		din <= "00000001";	wait for clk_period;din <= "00000010";					wait for clk_period;din <= "00000100";					wait for clk_period;din <= "00001000";					wait for clk_period;din <= "00010000";					wait for clk_period;din <= "00100000";					wait for clk_period;write_en <= '0';					wait for clk_period;  		read_en <= '1';						wait for clk_period*10;  			read_en <= '0';

（2） 运行结果

4.代码附录

1.VHDL文件fifo.vhd

```clibrary IEEE;use IEEE.STD_LOGIC_1164.ALL;use IEEE.STD_LOGIC_ARITH.ALL;use IEEE.STD_LOGIC_UNSIGNED.ALL;entity fifo is     port(	clk		:	in std_logic;	       	write_en	:	in std_logic;			read_en	:	in std_logic;			rst		:	in std_logic;	       	din		:	in std_logic_vector(7 downto 0);			dout		:	out std_logic_vector(7 downto 0);			empty		:	out std_logic;			full		:	out std_logic		);		 	  end fifo;architecture Behavioral of fifo is	type fifo_array is array(0 to 63)of std_logic_vector(7 downto 0);	signal 	fifo_memory	:	fifo_array;	signal 	full_flag		:	std_logic;	signal 	empty_flag	:	std_logic;	signal 	read_add		:	std_logic_vector(5 downto 0);	signal 	write_add		:	std_logic_vector(5 downto 0);	signal 	counter		:	std_logic_vector(5 downto 0);		 		 beginprocess(rst,clk)     begin	 	if(rst='0')	then		dout<="00000000";		elsif(clk'event and clk='1')	then			if(read_en ='1'and empty_flag='0')then				dout<=fifo_memory(conv_integer(read_add));			end if;		end if;end process;process(clk)     begin	 	if(clk'event and clk='1')then			if(rst='1'and write_en='1'and full_flag='0')then				fifo_memory(conv_integer(write_add))<= din;			end if;		end if;end process;process(rst,clk)     begin	 	if(rst='0')then		write_add<="000000";		elsif(clk'event and clk='1')then			if(write_en ='1'and full_flag='0') then	write_add <= write_add + 1;			end if;		end if;end process;process(rst,clk)	begin	if(rst='0')	then		read_add<="000000";	elsif(clk'event and clk='1')	then		if(read_en ='1'and empty_flag='0') then	read_add <= read_add + 1;		end if;	end if;end process;process(rst,clk)	variable temp : std_logic_vector( 1 downto 0 );begin	if(rst='0')then		counter<="000000";	elsif(clk'event and clk='1') then		temp := read_en & write_en;			case temp is 				when "00" =>		counter <= counter;				when "01" =>					if( counter /= "111111" ) then		counter <= counter + 1;					end if;				when "10" =>					if( counter /= "000000" ) then		counter <= counter - 1;					end if;				when "11" =>		counter <= counter;				when others =>	counter <= counter;				end case;		end if;end process;process( counter )begin	if( counter = "000000" ) then		empty_flag <= '1';	else 						empty_flag <= '0';	end if;end process;process( counter )begin	if( counter = "111111" ) then 		full_flag <= '1';	else 						full_flag <= '0';	end if;end process;full <= full_flag;empty <= empty_flag;end Behavioral;

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