--文件名：lcd_driver.vhd。
--功能：FGAD驅(qū)動(dòng)LCD顯示中文字符“年”。
--最后修改日期：2004.3.24。
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;
entity lcd_driver is
? Port ( clk : in std_logic;?--狀態(tài)機(jī)時(shí)鐘信號(hào)，同時(shí)也是液晶時(shí)鐘信號(hào)，其周期應(yīng)該滿(mǎn)足液晶數(shù)據(jù)的建立時(shí)間
??? reset:in std_logic;
?????? lcdda : out std_logic;???????? --寄存器選擇信號(hào)
?????? lcdrw : out std_logic;??????--液晶讀寫(xiě)信號(hào)
?????? lcden : out std_logic;??????--液晶時(shí)鐘信號(hào)
?????? data : out std_logic_vector(7 downto 0));??--液晶數(shù)據(jù)信號(hào)
end lcd_driver;

architecture Behavioral of lcd_driver is
type state is (set_dlnf,set_cursor,set_dcb,set _cgram,write _cgram,set_ddram,write_data);
? signal current_state:state;
? type ram2 is array(0 to 7) of std_logic_vector(7 downto 0);
constant cgram:ram2:=(("00001000"),("00001111"),("00010010"),
("00001111"),("00001010"),("00011111"),("00000010"),("00000010"));--年字符數(shù)據(jù)存儲(chǔ)器??????????????????????????
? signal clkk : std_logic;
begin
? lcden <=? clk ; --液晶時(shí)鐘信號(hào)
lcdrw <= '0' ;? --寫(xiě)數(shù)據(jù)

control:process(clk,reset,current_state)?????????????? --液晶驅(qū)動(dòng)控制器
? variable cnt1: std_logic_vector(2 downto 0);
begin
if reset='0'then
??? current_state<=set_dlnf;
cnt1:=(others => '1');
?lcdda<='0';