我正在使用VHDL和FPGA板，VGA接口和PS / 2键盘接口来创建迷宫并制作可以穿过迷宫的正方形。当我按下其中一个键（WASD）时，方块只移动一个位置，然后不再移动。每次按下其中一个键时我都需要它移动。这是我的代码：
ENTITY hw_image_generator IS
PORT(
ps2_code : IN STD_LOGIC_VECTOR(7 DOWNTO 0);
game_clk : IN STD_LOGIC;
disp_ena : IN STD_LOGIC; --display enable ('1' = display time, '0' = blanking time)
row : IN INTEGER; --row pixel coordinate
column : IN INTEGER; --column pixel coordinate
red : OUT STD_LOGIC_VECTOR(7 DOWNTO 0) := (OTHERS => '0'); --red magnitude output to DAC
green : OUT STD_LOGIC_VECTOR(7 DOWNTO 0) := (OTHERS => '0'); --green magnitude output to DAC
blue : OUT STD_LOGIC_VECTOR(7 DOWNTO 0) := (OTHERS => '0')); --blue magnitude output to DAC
END hw_image_generator;
ARCHITECTURE behavior OF hw_image_generator IS
signal x_position: INTEGER := 20;
signal y_position: INTEGER := 20;
CONSTANT max_count: NATURAL := 500000;
SIGNAL reset: STD_LOGIC;
BEGIN
PROCESS(game_clk, reset, x_position, y_position)
VARIABLE count : NATURAL range 0 to max_count;
BEGIN
IF (reset = '1') THEN
count := 0;
x_position <= 20;
y_position <= 20;
ELSIF(rising_edge(game_clk) AND count = 0) THEN
IF(count < max_count)THEN
IF(ps2_code = "00101001") THEN -- space bar
count := 0;
x_position <= 20;
y_position <= 20;
END IF;
IF(ps2_code = "00011101") THEN --W key
count := count + 1;
y_position <= y_position;
x_position <= x_position - 10;
END IF;
IF(ps2_code = "00011011") THEN --S key
count := count + 1;
y_position <= y_position;
x_position <= x_position + 10;
END IF;
IF(ps2_code = "00100011") THEN --D key
count := count + 1;
x_position <= x_position;
y_position <= y_position + 10;
END IF;
IF(ps2_code = "00011100") THEN --A key
count := count + 1;
x_position <= x_position;
y_position <= y_position - 10;
END IF;
ELSE
count := 0;
END IF;
END IF;
END PROCESS;
PROCESS(disp_ena, row, column)
BEGIN
IF(disp_ena = '1') THEN --display time
IF(row < 512 AND column > 231 AND column < 281) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 743 AND row < 793 AND column < 512) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 1024 AND column > 231 AND column < 281) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 256 AND row < 1024 AND column > 487 AND column < 537) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 487 AND row < 537 AND column > 536 AND column < 768) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 231 AND row < 281 AND column > 768) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 743 AND row < 793 AND column > 768) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSIF(row > 974 AND row < 1024 AND column > 536 AND column < 768) THEN
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
ELSE
red <= (OTHERS => '1');
green <= (OTHERS => '1');
blue <= (OTHERS => '1');
END IF;
IF(row > x_position AND row < x_position+50 AND column > y_position AND column < y_position+50) THEN
red <= (OTHERS => '1');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
END IF;
ELSE --blanking time
red <= (OTHERS => '0');
green <= (OTHERS => '0');
blue <= (OTHERS => '0');
END IF;
END PROCESS;
END behavior;
答案 0 :(得分：0)
在对game_clk敏感的未标记过程中：
process (game_clk, reset, x_position, y_position)
variable count: natural range 0 to max_count;
begin
if reset = '1' then
count := 0;
x_position <= 20;
y_position <= 20;
elsif rising_edge(game_clk) and count = 0 then
if count < max_count then
if ps2_code = "00101001" then -- space bar
count := 0;
x_position <= 20;
y_position <= 20;
end if;
if ps2_code = "00011101" then --w key
count := count + 1;
y_position <= y_position;
x_position <= x_position - 10;
end if;
if ps2_code = "00011011" then --s key
count := count + 1;
y_position <= y_position;
x_position <= x_position + 10;
end if;
if ps2_code = "00100011" then --d key
count := count + 1;
x_position <= x_position;
y_position <= y_position + 10;
end if;
if ps2_code = "00011100" then --a key
count := count + 1;
x_position <= x_position;
y_position <= y_position - 10;
end if;
else
count := 0;
end if;
end if;
end process;
请注意，灵敏度列表中不需要x_position和y_position。所有信号分配都是由于重置事件或game_clk事件造成的。
另请注意elsif条件中的count = 0启用：
elsif rising_edge(game_clk) and count = 0 then
以下if语句中的条件：
if count < max_count then
一旦你的ps2_code识别器（空格键除外）有效，你就会增加计数，不再启用你在game_clk上升沿分配的任何触发器和寄存器。你也无法判断你是否击中了连续的空格键。没有打另一个识别器。
您的代码符合您对问题的描述，这是一项功能。
答案 1 :(得分：0)
PROCESS(game_clk)
BEGIN
IF(game_clk'EVENT AND game_clk = '1')THEN
count <= count + 1;
IF(count = 5000000 AND ps2_code = "00101001")THEN --space key
count <= 0;
x_position <= 20;
y_position <= 20;
END IF;
IF(count = 5000000 AND ps2_code = "00011101")THEN --W key
count <= 0;
IF((y_position > 0 AND y_position < 181 AND x_position > 0 and x_position < 512) --1
OR (y_position > 0 AND y_position < 437 AND x_position > 512 AND x_position < 693) --2
OR (y_position > 281 AND y_position < 437 AND x_position > 0 and x_position < 512) --3
OR (y_position > 437 AND y_position < 537 AND x_position > 0 AND x_position < 206) --4
OR (y_position > 537 AND y_position < 1227 AND x_position > 0 AND x_position < 181) --5
OR (y_position > 537 AND y_position < 718 AND x_position > 181 AND x_position < 437) --6
OR (y_position > 768 AND y_position < 1227 AND x_position > 281 AND x_position < 718) --7
OR (y_position > 537 AND y_position < 768 AND x_position > 537 AND x_position < 693) --8
OR (y_position > 537 AND y_position < 718 AND x_position > 693 AND x_position < 793) --9
OR (y_position > 537 AND y_position < 768 AND x_position > 793 AND x_position < 975) --10
OR (y_position > 768 AND y_position < 1227 AND x_position > 793 AND x_position < 1027) --11
OR (y_position > 718 AND y_position < 768 AND x_position > 281 AND x_position < 437) --12
) THEN
x_position <= x_position - 10;
ELSE
x_position <= x_position + 5;
y_position <= y_position;
END IF;
ELSIF(count = 5000000 AND ps2_code = "00011011") THEN --S key
count <= 0;
IF((y_position > 0 AND y_position < 181 AND x_position > 0 and x_position < 512) --1
OR (y_position > 0 AND y_position < 437 AND x_position > 512 AND x_position < 693) --2
OR (y_position > 281 AND y_position < 437 AND x_position > 0 and x_position < 512) --3
OR (y_position > 437 AND y_position < 537 AND x_position > 0 AND x_position < 206) --4
OR (y_position > 537 AND y_position < 1227 AND x_position > 0 AND x_position < 181) --5
OR (y_position > 537 AND y_position < 718 AND x_position > 181 AND x_position < 437) --6
OR (y_position > 768 AND y_position < 1227 AND x_position > 281 AND x_position < 718) --7
OR (y_position > 537 AND y_position < 768 AND x_position > 537 AND x_position < 693) --8
OR (y_position > 537 AND y_position < 718 AND x_position > 693 AND x_position < 793) --9
OR (y_position > 537 AND y_position < 768 AND x_position > 793 AND x_position < 975) --10
OR (y_position > 768 AND y_position < 1227 AND x_position > 793 AND x_position < 1027) --11
OR (y_position > 718 AND y_position < 768 AND x_position > 281 AND x_position < 437) --12
) THEN
x_position <= x_position + 10;
ELSE
x_position <= x_position - 5;
y_position <= y_position;
END IF;
ELSIF(count = 5000000 AND ps2_code = "00100011") THEN --D key
count <= 0;
IF((y_position > 0 AND y_position < 181 AND x_position > 0 and x_position < 512) --1
OR (y_position > 0 AND y_position < 437 AND x_position > 512 AND x_position < 693) --2
OR (y_position > 281 AND y_position < 437 AND x_position > 0 and x_position < 512) --3
OR (y_position > 437 AND y_position < 537 AND x_position > 0 AND x_position < 206) --4
OR (y_position > 537 AND y_position < 1227 AND x_position > 0 AND x_position < 181) --5
OR (y_position > 537 AND y_position < 718 AND x_position > 181 AND x_position < 437) --6
OR (y_position > 768 AND y_position < 1227 AND x_position > 281 AND x_position < 718) --7
OR (y_position > 537 AND y_position < 768 AND x_position > 537 AND x_position < 693) --8
OR (y_position > 537 AND y_position < 718 AND x_position > 693 AND x_position < 793) --9
OR (y_position > 537 AND y_position < 768 AND x_position > 793 AND x_position < 975) --10
OR (y_position > 768 AND y_position < 1227 AND x_position > 793 AND x_position < 1027) --11
OR (y_position > 718 AND y_position < 768 AND x_position > 281 AND x_position < 437) --12
) THEN
y_position <= y_position + 10;
ELSE
x_position <= x_position;
y_position <= y_position -5;
END IF;
ELSIF(count = 5000000 AND ps2_code = "00011100") THEN --A key
count <= 0;
IF((y_position > 0 AND y_position < 181 AND x_position > 0 and x_position < 512) --1
OR (y_position > 0 AND y_position < 437 AND x_position > 512 AND x_position < 693) --2
OR (y_position > 281 AND y_position < 437 AND x_position > 0 and x_position < 512) --3
OR (y_position > 437 AND y_position < 537 AND x_position > 0 AND x_position < 206) --4
OR (y_position > 537 AND y_position < 1227 AND x_position > 0 AND x_position < 181) --5
OR (y_position > 537 AND y_position < 718 AND x_position > 181 AND x_position < 437) --6
OR (y_position > 768 AND y_position < 1227 AND x_position > 281 AND x_position < 718) --7
OR (y_position > 537 AND y_position < 768 AND x_position > 537 AND x_position < 693) --8
OR (y_position > 537 AND y_position < 718 AND x_position > 693 AND x_position < 793) --9
OR (y_position > 537 AND y_position < 768 AND x_position > 793 AND x_position < 975) --10
OR (y_position > 768 AND y_position < 1227 AND x_position > 793 AND x_position < 1027) --11
OR (y_position > 718 AND y_position < 768 AND x_position > 281 AND x_position < 437) --12
) THEN
y_position <= y_position - 10;
ELSE
x_position <= x_position;
y_position <= y_position +5;
END IF;
END IF;
END IF;
END PROCESS;