Subversion Repositories 16x2_lcd_controller

-------------------------------------------------------------------------------

-- Title      : Synthesizable demo for design "lcd16x2_ctrl"

-- Project    : 

-------------------------------------------------------------------------------

-- File       : lcd16x2_ctrl_tb.vhd

-- Author     :   <stachelsau@T420>

-- Company    : 

-- Created    : 2012-07-28

-- Last update: 2012-07-29

-- Platform   : 

-- Standard   : VHDL'93/02

-------------------------------------------------------------------------------

-- Description: This demo writes writes a "hello world" to the display and

-- interchanges both lines periodically.

-------------------------------------------------------------------------------

-- Copyright (c) 2012 

-------------------------------------------------------------------------------

-- Revisions  :

-- Date        Version  Author  Description

-- 2012-07-28  1.0      stachelsau      Created

-------------------------------------------------------------------------------

library ieee;

use ieee.std_logic_1164.all;

-------------------------------------------------------------------------------

entity lcd16x2_ctrl_demo is

  port (

    clk    : in  std_logic;

    lcd_e  : out std_logic;

    lcd_rs : out std_logic;

    lcd_rw : out std_logic;

    lcd_db : out std_logic_vector(7 downto 4));

end entity lcd16x2_ctrl_demo;

-------------------------------------------------------------------------------

architecture behavior of lcd16x2_ctrl_demo is

  -- 

  signal timer : natural range 0 to 100000000 := 0;

  signal switch_lines : std_logic := '0';

  signal line1 : std_logic_vector(127 downto 0);

  signal line2 : std_logic_vector(127 downto 0);

  -- component generics

  constant CLK_PERIOD_NS : positive := 10;  -- 100 Mhz

  -- component ports

  signal rst          : std_logic;

  signal line1_buffer : std_logic_vector(127 downto 0);

  signal line2_buffer : std_logic_vector(127 downto 0);

begin  -- architecture behavior

  -- component instantiation

  DUT : entity work.lcd16x2_ctrl

    generic map (

      CLK_PERIOD_NS => CLK_PERIOD_NS)

    port map (

      clk          => clk,

      rst          => rst,

      lcd_e        => lcd_e,

      lcd_rs       => lcd_rs,

      lcd_rw       => lcd_rw,

      lcd_db       => lcd_db,

      line1_buffer => line1_buffer,

      line2_buffer => line2_buffer);

  rst <= '0';

  -- see the display's datasheet for the character map

  line1(127 downto 120) <= X"20";

  line1(119 downto 112) <= X"20";

  line1(111 downto 104) <= X"48";  -- H

  line1(103 downto 96)  <= X"65";  -- e

  line1(95 downto 88)   <= X"6c";  -- l

  line1(87 downto 80)   <= X"6c";  -- l

  line1(79 downto 72)   <= X"6f";  -- o

  line1(71 downto 64)   <= X"20";

  line1(63 downto 56)   <= X"57";  -- W

  line1(55 downto 48)   <= X"6f";  -- o

  line1(47 downto 40)   <= X"72";  -- r

  line1(39 downto 32)   <= X"6c";  -- l

  line1(31 downto 24)   <= X"64";  -- d

  line1(23 downto 16)   <= X"21";  -- !

  line1(15 downto 8)    <= X"20";

  line1(7 downto 0)     <= X"20";

  line2(127 downto 120) <= X"30";

  line2(119 downto 112) <= X"31";

  line2(111 downto 104) <= X"32";

  line2(103 downto 96)  <= X"33";

  line2(95 downto 88)   <= X"34";

  line2(87 downto 80)   <= X"35";

  line2(79 downto 72)   <= X"36";

  line2(71 downto 64)   <= X"37";

  line2(63 downto 56)   <= X"38";

  line2(55 downto 48)   <= X"39";

  line2(47 downto 40)   <= X"3a";

  line2(39 downto 32)   <= X"3b";

  line2(31 downto 24)   <= X"3c";

  line2(23 downto 16)   <= X"3d";

  line2(15 downto 8)    <= X"3e";

  line2(7 downto 0)     <= X"3f";

  line1_buffer <= line2 when switch_lines = '1' else line1;

  line2_buffer <= line1 when switch_lines = '1' else line2;

  -- switch lines every second

  process(clk)

  begin

    if rising_edge(clk) then

      if timer = 0 then

        timer <= 100000000;

        switch_lines <= not switch_lines;

      else

        timer <= timer - 1;

      end if;

    end if;

  end process;

end architecture behavior;