以下是按键连击电路的VHDL代码:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;
entity button_counter is
Port ( clk : in STD_LOGIC;
button : in STD_LOGIC;
reset : in STD_LOGIC;
digit_out : out STD_LOGIC_VECTOR (3 downto 0);
segment_out : out STD_LOGIC_VECTOR (6 downto 0));
end button_counter;
architecture Behavioral of button_counter is
signal counter : unsigned(7 downto 0) := (others => '0');
signal prev_button : std_logic := '0';
signal count_enable : std_logic := '0';
signal count_ended : std_logic := '0';
signal clock_count : unsigned(23 downto 0) := (others => '0');
begin
-- Clock divider
process(clk)
begin
if rising_edge(clk) then
if clock_count = 24999999 then
clock_count <= (others => '0');
count_ended <= '1';
else
clock_count <= clock_count + 1;
count_ended <= '0';
end if;
end if;
end process;
-- Button counter
process(clk, reset)
begin
if reset = '1' then
counter <= (others => '0');
prev_button <= '0';
count_enable <= '0';
elsif rising_edge(clk) then
if button = '1' and prev_button = '0' then
count_enable <= '1';
prev_button <= '1';
else
count_enable <= '0';
prev_button <= button;
end if;
if count_enable = '1' then
counter <= counter + 1;
end if;
end if;
end process;
-- Display driver
process(counter, count_ended)
variable temp : unsigned(7 downto 0);
begin
if count_ended = '1' then
temp := (others => '0');
else
temp := counter;
end if;
case temp is
when "00000000" =>
digit_out <= "1111";
segment_out <= "0000001";
when "00000001" =>
digit_out <= "1110";
segment_out <= "1001111";
when "00000010" =>
digit_out <= "1101";
segment_out <= "0010010";
when "00000011" =>
digit_out <= "1100";
segment_out <= "0000110";
when "00000100" =>
digit_out <= "1011";
segment_out <= "1001100";
when "00000101" =>
digit_out <= "1010";
segment_out <= "0100100";
when "00000110" =>
digit_out <= "1001";
segment_out <= "0100000";
when "00000111" =>
digit_out <= "1000";
segment_out <= "0001111";
when "00001000" =>
digit_out <= "0111";
segment_out <= "0000000";
when "00001001" =>
digit_out <= "0110";
segment_out <= "0000100";
when "00001010" =>
digit_out <= "0101";
segment_out <= "0001000";
when "00001011" =>
digit_out <= "0100";
segment_out <= "1100000";
when "00001100" =>
digit_out <= "0011";
segment_out <= "0110001";
when "00001101" =>
digit_out <= "0010";
segment_out <= "1000010";
when "00001110" =>
digit_out <= "0001";
segment_out <= "0110000";
when "00001111" =>
digit_out <= "0000";
segment_out <= "0111000";
when others =>
digit_out <= "1111";
segment_out <= "1111111";
end case;
end process;
end Behavioral;
该电路包含一个时钟分频器,一个按键计数器和一个数码管显示驱动器。时钟分频器将输入时钟分频为1秒,按键计数器在每次按键时增加计数器的值,数码管显示驱动器将计数器的值转换为七段数码管的显示。
以下是按键连击电路的测试台代码:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity button_counter_tb is
end button_counter_tb;
architecture Behavioral of button_counter_tb is
component button_counter is
Port ( clk : in STD_LOGIC;
button : in STD_LOGIC;
reset : in STD_LOGIC;
digit_out : out STD_LOGIC_VECTOR (3 downto 0);
segment_out : out STD_LOGIC_VECTOR (6 downto 0));
end component;
signal clk : std_logic := '0';
signal button : std_logic := '0';
signal reset : std_logic := '0';
signal digit_out : std_logic_vector(3 downto 0);
signal segment_out : std_logic_vector(6 downto 0);
begin
uut: button_counter
port map (clk, button, reset, digit_out, segment_out);
clk_process : process
begin
clk <= '0';
wait for 10 ns;
clk <= '1';
wait for 10 ns;
end process;
reset_process : process
begin
reset <= '1';
wait for 5 ns;
reset <= '0';
wait for 100 ns;
reset <= '1';
wait;
end process;
button_process : process
begin
button <= '0';
wait for 50 ns;
button <= '1';
wait for 10 ns;
button <= '0';
wait for 20 ns;
button <= '1';
wait for 30 ns;
button <= '0';
wait for 60 ns;
button <= '1';
wait for 40 ns;
button <= '0';
wait for 70 ns;
button <= '1';
wait for 80 ns;
button <= '0';
wait for 90 ns;
button <= '1';
wait for 100 ns;
button <= '0';
wait for 150 ns;
button <= '1';
wait for 200 ns;
button <= '0';
wait;
end process;
end Behavioral;
该测试台代码生成一个时钟信号和一系列模拟按键按下的事件。在仿真中,可以观察到计数器的值随着按键的按下而增加,并在每秒钟重置。数码管显示也会更新以显示当前计数器的值。