使用FPGA进行图像处理时，通常需要将TXT文件中的图像数据读出到TestBench中，并将仿真的结果写入到TXT文件中，用于确认图像处理的结果是否正确。
VHDL中TXT文件的读写操作如下所示，
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-- Company:
-- Engineer:
--
-- Create Date: 2025/04/18 21:34:38
-- Design Name:
-- Module Name: tb_txt_rdwr - Behavioral
-- Project Name:
-- Target Devices:
-- Tool Versions:
-- Description:
--
-- Dependencies:
--
-- Revision:
-- Revision 0.01 - File Created
-- Additional Comments:
--
----------------------------------------------------------------------------------library IEEE;
use ieee.std_logic_1164.all;
use ieee.std_logic_arith.all;
use ieee.std_logic_unsigned.all;
use ieee.std_logic_textio.all;
use std.textio.all;-- testio程序包是std库的一部分-- Uncomment the following library declaration if using
-- arithmetic functions with Signed or Unsigned values
--use IEEE.NUMERIC_STD.ALL;-- Uncomment the following library declaration if instantiating
-- any Xilinx leaf cells in this code.
--library UNISIM;
--use UNISIM.VComponents.all;entity tb_txt_rdwr is
-- Port ( );
end tb_txt_rdwr;architecture Behavioral of tb_txt_rdwr isconstant clk_period : time := 10 ns; signal clk : std_logic;
signal rst : std_logic;signal wrdata : std_logic_vector(3 downto 0);
signal wren : std_logic;
signal wrdone : std_logic;signal rddata : std_logic_vector(3 downto 0);
signal rden : std_logic;
signal rddone : std_logic;begin-----------------------------------
--生成时钟复位信号
process
beginclk <= '0'; wait for clk_period/2;clk <= '1'; wait for clk_period/2;
end process;process
beginrst <= '1';wait for clk_period*200;rst <= '0';wait ;
end process;-----------------------------------
--生成要写入TXT文件中的二进制数据
process
beginwrdata <= (others=>'0');wren <= '0';wrdone <= '0';wait until falling_edge(rst);wait until rising_edge(clk);wait until rising_edge(clk);wait until rising_edge(clk);for i in 15 downto 0 loop wren <= '1';wait until rising_edge(clk);wrdata <= wrdata + x"1";end loop;wren <= '0'; wait until rising_edge(clk);wait until rising_edge(clk);wait until rising_edge(clk); wrdone <= '1';wait until rising_edge(clk);wrdone <= '0';wait ;
end process;-----------------------------------
--写数据到TXT文件中
process(clk,rst)file v_file : text;variable v_line : line;variable v_data : std_logic_vector(3 downto 0);
beginif rst='1' thenfile_open(v_file,"E:\forsim\txt_from_vhdl_tb.txt",write_mode);elsif rising_edge(clk) thenif wren='1' thenv_data := wrdata;write(v_line,v_data);writeline(v_file,v_line);elsif wrdone='1' thenfile_close(v_file);end if;end if;
end process;-----------------------------------
--生成TXT文件的读使能信号和读结束信号
process
beginrden <= '0';rddone <= '0';wait until falling_edge(wrdone); --检测到TXT文件写操作结束后，从TXT文件中读出写入的数据wait until rising_edge(clk);wait until rising_edge(clk);wait until rising_edge(clk);for i in 15 downto 0 loop rden <= '1';wait until rising_edge(clk);end loop;rden <= '0';wait until rising_edge(clk);wait until rising_edge(clk);wait until rising_edge(clk);rddone <= '1';wait until rising_edge(clk);rddone <= '0';wait ;
end process;-----------------------------------
--从TXT文件中读出数据，并赋值到rdtata
process(clk,rst)file v_file : text;variable v_line : line;variable v_data : std_logic_vector(3 downto 0);
beginif rst='1' thenfile_open(v_file,"E:\forsim\txt_from_vhdl_tb.txt",read_mode);rddata <= (others=>'0');elsif rising_edge(clk) thenif rden='1' thenreadline(v_file,v_line);read(v_line,v_data);rddata <= v_data;elsif rddone='1' thenfile_close(v_file);end if;end if;
end process;end Behavioral;
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