lcd1602 vhdl程序问题，求大牛指导啊！！

lixuecheng · 发表于 2011-11-1 10:59:08

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library ieee;
use ieee.std_logic_1164.all;
use ieee.std_logic_unsigned.all;
entity lcd is
port(clk:in std_logic;
rst:in std_logic;
rs:out std_logic;
rw:out std_logic;
ren:out std_logic;
lcd_data:out std_logic_vector(7 downto 0));
end lcd;
architecture behav of lcd is
type state is (set_function,set_clear,set_swtich,set_inmode,set_drram,set_writeram_1,set_writeram_2,set_idle);
signal current_state:state:=set_clear;
signal data_buf:std_logic_vector(7 downto 0);
signal Clk_Out:std_logic;
signal Lcd_clk:std_logic;
signal cnt : std_logic_vector(20 downto 0);
begin
ren <= Clk_Out;
div_clk:process(clk,rst)
--variable cnt:integer:=0;
--signal clk_buf:std_logic;
begin
if(rst = '0')then
cnt <= (others => '0');
elsif(rising_edge(clk))then
cnt<= cnt + 1;
if(cnt = 0)then
Clk_Out <= not Clk_Out;
end if;
end if;
LCD_clk <= Clk_Out;
--begin
--if rst='0'then
-- cnt:=0;
--elsif clk'event and clk='1' then
--
--if cnt<=55555 then
-- clk_buf<='0';
-- cnt:=cnt+1;
--else
-- clk_buf<=not clk_buf;
-- cnt:=0;
--end if;
--end if;
--ren<=clk_buf;
end process div_clk;
lcd_ctrl:process(Lcd_clk,rst,current_state)
variable cntt:integer:=0;
begin
if (rst='0') then
rs<='0';
rw<='0';
data_buf<="00000000";
current_state<=set_clear;
elsif Lcd_clk'event and Lcd_clk='1' then
--cntt:=cntt+1;
case current_state is
when set_clear=>rs<='0';
rw<='0';
data_buf<="00000001";
current_state<=set_function;
when set_function=>rs<='0';
rw<='0';
data_buf<="00111000";
current_state<=set_inmode;
when set_inmode=>rs<='0';
rw<='0';
data_buf<="00000110";
current_state<=set_swtich;
when set_swtich=>rs<='0';
rw<='0';
data_buf<="00001100";
current_state<=set_drram;
when set_drram=>rs<='0';
rw<='0';
data_buf<="10000000";
current_state<=set_writeram_1;
when set_writeram_1=>rs<='1';
rw<='0';
if cntt=16 then
cntt:=0;
rs<='0';
data_buf<="11000000";
current_state<=set_writeram_2;
else
cntt:=cntt+1;
case cntt is
when 1=>data_buf<="01010111";
when 2=>data_buf<="01010111";
when 3=>data_buf<="01010111";
when 4=>data_buf<="00101110";
when 5=>data_buf<="01001110";
when 6=>data_buf<="01000010";
when 7=>data_buf<="01010101";
when 8=>data_buf<="00101110";
when 9=>data_buf<="01000101";
when 10=>data_buf<="01000100";
when 11=>data_buf<="01010101";
when 12=>data_buf<="00101110";
when 13=>data_buf<="01000011";
when 14=>data_buf<="01001110";
when 15=>data_buf<="10100000";
when 16=>data_buf<="10100000";
--current_state<=set_writeram_1;
when others=>null;
--cntt:=0;
end case;
current_state<=set_writeram_1;
end if;
when set_writeram_2=>rs<='1';
rw<='0';
if cntt=16 then
cntt:=0;
rs<='0';
rw<='0';
current_state<=set_idle;
else
--cntt:=0;
cntt:=cntt+1;
case cntt is
when 1=>data_buf<="01010111";
when 2=>data_buf<="01010111";
when 3=>data_buf<="01010111";
when 4=>data_buf<="00101110";
when 5=>data_buf<="01001110";
when 6=>data_buf<="01000010";
when 7=>data_buf<="01010101";
when 8=>data_buf<="00101110";
current_state<=set_writeram_2;
when 9=>data_buf<="01000101";
when 10=>data_buf<="01000100";
when 11=>data_buf<="01010101";
when 12=>data_buf<="00101110";
when 13=>data_buf<="01000011";
when 14=>data_buf<="01001110";
when 15=>data_buf<="10100000";
when 16=>data_buf<="10100000";
when others=>null;
end case;
current_state<=set_writeram_2;
end if;
when set_idle=>current_state<=set_idle;
end case;
lcd_data<=data_buf;
end if;
end process lcd_ctrl;
end behav;

复制代码

我是要显示两行，因为lcd1602是两行的，但为什么程序写到第二行时（set_writeram_2）是从cntt=8那里执行，前面的不执行，结果第二行就显示了几个字符，第一行正常显示！

dlb05061131 · 发表于 2011-11-4 19:25:20

这样一个代码，别人怎么可以帮你看这些细节的东西呀，还是自己跑跑仿真看看有什么问题吧。

[求助] lcd1602 vhdl程序问题，求大牛指导啊！！

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