基本功能：
1、通過FPGA板的VGA接口在顯示器上分別顯示不同顏色的橫向、豎直條紋圖案，橫向條紋和豎直條紋的切換通過FPGA板上的按鍵實現。
2、通過VGA控制器，在屏幕上顯示640*480的單色背景，並在該背景上疊加一個小方塊，該小方塊能夠在屏幕上上下左右移動，實現屏幕保護的效果。3、VGA單色的背景色自定，小方塊的大小自定；
4、該小方塊能夠按照一定的軌跡在屏幕上運行，速度適中。
大三下學期的實驗，貼出代碼僅供參考：
1、分頻模塊：
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity fenpin is
port
(
clk_fp_in :in std_logic;
reset_fp :in std_logic;
clk_fp_out :out std_logic;
clk_fp_dis :out std_logic
);
end fenpin;
architecture Behavioral of fenpin is
signal clk_signal :std_logic;
signal clk_dis :std_logic;
signal cnt:integer range 999999 downto 0 :=0;--移動
begin
process(clk_fp_in,reset_fp)
begin
if(reset_fp='1')then
clk_signal<= '0';
elsif(clk_fp_in'eventand clk_fp_in = '1')then
if(clk_signal= '0')then
clk_signal<= '1';
else
clk_signal<= '0';
endif;
endif;
endprocess;
clk_fp_out<= clk_signal;
process(clk_fp_in,reset_fp)
begin
if(reset_fp='1')then
cnt<= 0;
clk_dis<= '0';
elsif(clk_fp_in'eventand clk_fp_in = '1')then
if(cnt< 499999)then
cnt<= cnt+1;
clk_dis<= '1';
elsif(cnt= 999999)then
cnt<= 0;
else
cnt<= cnt+1;
clk_dis<= '0';
endif;
endif;
endprocess;
clk_fp_dis<= clk_dis;
end Behavioral;
2、VGA控制模塊：
library IEEE;
useIEEE.STD_LOGIC_1164.ALL;
USEIEEE.STD_LOGIC_UNSIGNED.ALL;
entity sync is
port( clk_sync :instd_logic;
reset_sync :in std_logic;
V_sync :out std_logic;
H_sync :out std_logic;
Ready_sync :out std_logic;
Lie_Add_sync :out integer range 800 downto 0;
Hang_Add_sync :out integer range 525 downto 0
);
end sync;
architectureBehavioral of sync is
signal count_h:integer range 800 downto 0;
signal count_v:integer range 525 downto 0;
signal isReady :std_logic;
begin
process (clk_sync,reset_sync)
begin
if(reset_sync='1')then
count_h <= 0;
H_sync <= '0';
elsif(clk_sync'event and clk_sync='1')then
if(count_h=799)then
count_h <= 0;
else
count_h <=count_h + 1;
if(count_h <96)then
H_sync <= '0';
else
H_sync <= '1';
end if;
end if;
end if;
end process;
process (clk_sync,reset_sync)
begin
if(reset_sync='1')then
count_v <= 0;
V_sync <= '0';
elsif(clk_sync'event and clk_sync='1')then
if(count_v = 524)then
count_v <= 0;
elsif(count_h=799)then
count_v <=count_v + 1;
else
if(count_v <3)then
V_sync <='0';
else
V_sync <='1';
end if;
end if;
end if;
end process;
process (reset_sync,clk_sync)
begin
if(reset_sync='1')then
isReady <= '0';
Lie_Add_sync <= 0;
Hang_Add_sync<= 0;
elsif(clk_sync'event and clk_sync='1')then
if((count_h >144)and(count_h < 785)and(count_v > 34)and(count_v < 515))then
isReady <= '1';
Lie_Add_sync <=count_h - 145;
Hang_Add_sync<=count_v - 35;
else
isReady <= '0';
Lie_Add_sync <=0;
Hang_Add_sync<=0;
end if;
end if;
end process;
Ready_sync <= isReady;
end Behavioral;
3、VGA顯示模塊：
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
USEIEEE.STD_LOGIC_ARITH.ALL;
entityvga_control is
port( clk_vga :instd_logic;
signal_dis :in std_logic;
reset_vga :in std_logic;
choose_vga :in std_logic;
Ready_vga :in std_logic;
Lie_Add_vga :in integer range 800 downto 0; --0~640
Hang_Add_vga:in integer range 525downto 0; --0~480
rom_add :out std_logic_vector (13 downto 0);
rom_data :in std_logic_vector (7 downto 0);
RGB_vga_out :out std_logic_vector (7 downto 0);
RGB_vga_in :in std_logic_vector (7 downto 0)
);
end vga_control;
architectureBehavioral of vga_control is
type state is(s0,s1,s2,s3);--狀態機類型
signalcurrent:state;
signal x:integerrange 639 downto 0 :=100;--移動
signal y:integerrange 479 downto 0 :=100;--移動
signalx_signal:std_logic;
signaly_signal:std_logic;
signal move :std_logic;
begin
process(choose_vga,reset_vga)
begin
if(reset_vga ='1')then
current <=s0;
elsif(choose_vga'event andchoose_vga ='0')then--檢測到下降沿纔開始響應
case current is
when s0 =>
current <=s1;
when s1 =>
current <=s2;
when s2 =>
current <=s3;
when s3 =>
current <=s0;
when others =>
current <=s0;
end case;
end if;
end process;
process (clk_vga,reset_vga)
begin
if(reset_vga='1')then
RGB_vga_out <="00000000";
move <='1';
elsif(clk_vga'event and clk_vga ='1')then
if(Ready_vga='1')then --可以顯示
case current is
when s0=>--豎條紋
caseLie_Add_vga is --0~640
when0 to 79 =>RGB_vga_out <= "11100000";--紅，藍，綠，藍，紅，綠， 紅，藍
when 80 to 159 =>RGB_vga_out <= "00000011";
when160 to 239 => RGB_vga_out <="00011100";
when240 to 319 => RGB_vga_out <="00000011";
when320 to 399 => RGB_vga_out <="11100000";
when400 to 479 => RGB_vga_out <="00011100";
when480 to 559 => RGB_vga_out <="11100000";
when560 to 639 => RGB_vga_out <="00000011";
whenothers => RGB_vga_out<= "00000000";
endcase;
when s1=>--橫條紋
caseHang_Add_vga is --0~480
when0 to 59 =>RGB_vga_out <= "11100000";--紅，藍，綠，藍，紅，綠， 紅，藍
when60 to 119 => RGB_vga_out <= "00000011";
when120 to 179 => RGB_vga_out <="00011100";
when180 to 239 => RGB_vga_out <="00000011";
when240 to 299 => RGB_vga_out <="11100000";
when300 to 359 => RGB_vga_out <="00011100";
when360 to 419 => RGB_vga_out <="11100000";
when420 to 479 => RGB_vga_out <="00000011";
whenothers => RGB_vga_out<= "00000000";
endcase;
when s2=>--調色觀察
if(Hang_Add_vga> y and Hang_Add_vga< 128+y and Lie_Add_vga>x andLie_Add_vga < 128+x )then
move <='0';
RGB_vga_out<= RGB_vga_in;
else
move <='1';
RGB_vga_out<= "00000000";
endif;
when s3=>--屏保
if(Hang_Add_vga>y and Hang_Add_vga< 128+y and Lie_Add_vga>x and Lie_Add_vga <128+x)then
move <='0';
rom_add<= conv_std_logic_vector((Hang_Add_vga-y)*128 + Lie_Add_vga-x,14);
RGB_vga_out<= rom_data;
else
move <='1';--使用這個信號只是爲了讓掃描完一次再移動，但由於背景跟圖片顏色不一樣，還是有拖影，所以，這個信號可以不用！
RGB_vga_out<= "00000000";
endif;
when others=>
RGB_vga_out<= "00000000";
end case;
end if;
end if;
end process;
--屏保圖片的移動實現
process(reset_vga,signal_dis)
begin
if(reset_vga='1')then
x_signal <='1';
x <=0;
elsif(signal_dis'event andsignal_dis ='1')then
if(move='1')then
if(x_signal ='1')then
if(x<634-128)then
x<= x+1;
else
x<= x-1;
x_signal<='0';
end if;
else
if(x<1)then
x<= x+1;
x_signal<='1';
else
x<= x-1;
end if;
end if;
end if;
end if;
end process;
process(reset_vga,signal_dis)
begin
if(reset_vga='1')then
y_signal <='1';
y <=0;
elsif(signal_dis'event andsignal_dis ='1')then
if(move='1')then
if(y_signal ='1')then
if(y<479-128)then
y<= y+1;
else
y<= y-1;
y_signal<='0';
end if;
else
if(y<1)then
y<= y+1;
y_signal<='1';
else
y<= y-1;
end if;
end if;
end if;
end if;
end process;
end Behavioral;
5、頂層模塊：
library IEEE;
useIEEE.STD_LOGIC_1164.ALL;
entity VGA_top is
port( clk :instd_logic; --50M時鐘輸入
reset :in std_logic; --復位，高有效
choose :in std_logic;
--pll_led :out std_logic; --提示PLL正常工作的LED
V :outstd_logic;
H :outstd_logic;
RGB :out std_logic_vector (7 downto 0);
RGB_top :in std_logic_vector (7 downto 0)
);
end VGA_top;
architectureBehavioral of VGA_top is
component fenpin
port( clk_fp_in : in std_logic;
reset_fp :in std_logic;
clk_fp_out :out std_logic;
clk_fp_dis :out std_logic
);
end component;
component sync
port( clk_sync :instd_logic;
reset_sync :in std_logic;
V_sync :out std_logic;
H_sync :out std_logic;
Ready_sync :out std_logic;
Lie_Add_sync :out integer range 800 downto 0;
Hang_Add_sync :out integer range 525 downto 0
);
end component;
component vga_control
port( clk_vga :instd_logic;
signal_dis :in std_logic;
reset_vga :in std_logic;
choose_vga :in std_logic;
Ready_vga :in std_logic;
Lie_Add_vga :in integer range 800 downto 0; --0~640
Hang_Add_vga:ininteger range 525 downto 0; --0~480
rom_add :out std_logic_vector (13 downto 0);
rom_data :in std_logic_vector (7 downto 0);
RGB_vga_out :out std_logic_vector (7 downto 0);
RGB_vga_in :in std_logic_vector (7 downto 0)
);
end component;
COMPONENT rom1
PORT (
clka : IN STD_LOGIC;
addra : IN STD_LOGIC_VECTOR(13 DOWNTO 0);
douta : OUT STD_LOGIC_VECTOR(7 DOWNTO 0)
);
END COMPONENT;
signal clk_sig :std_logic;
signal clk_dis :std_logic;
signal Ready :std_logic;
signal Lie_Add :integer range 800 downto0; --0~640
signal Hang_Add:integer range 525 downto0; --0~480
signal rom_add_signal:STD_LOGIC_VECTOR(13 DOWNTO 0);
signal rom_data_signal:STD_LOGIC_VECTOR(7DOWNTO 0);
begin
u1:fenpin
port map( clk,
reset,
clk_sig,
clk_dis
);
u2:sync
port map( clk_sig,
reset,
V,
H,
Ready,
Lie_Add,
Hang_Add
);
u3:vga_control
port map( clk_sig,
clk_dis,
reset,
choose,
Ready,
Lie_Add,
Hang_Add,
rom_add_signal,
rom_data_signal,
RGB,
RGB_top
);
u4:rom1
PORT map( clk_sig,
rom_add_signal,
rom_data_signal
);
end Behavioral;
FPGA開發板截圖：
