帮我写一个vhdl的矩阵键盘控制的步进电机控制器

好的，下面是一个基于VHDL语言的矩阵键盘控制的步进电机控制器的代码实现。

实现的功能为：通过按下矩阵键盘中的某个键，来控制步进电机旋转的方向和步进的速度。

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

entity stepper_motor_controller is
    port (
        clk: in std_logic;
        reset: in std_logic;
        matrix_row: in std_logic_vector(3 downto 0);
        matrix_col: in std_logic_vector(3 downto 0);
        enable: in std_logic;
        direction: out std_logic;
        step: out std_logic
    );
end stepper_motor_controller;

architecture Behavioral of stepper_motor_controller is
    signal counter: unsigned(15 downto 0) := (others => '0');
    signal pulse: std_logic := '0';

    constant PULSE_WIDTH: integer := 10; -- 脉冲宽度
    constant MAX_COUNT: integer := 1000; -- 最大计数值，控制脉冲频率
    constant STEP_DELAY: integer := 100000; -- 步进延迟

    type matrix_key is array (0 to 3, 0 to 3) of std_logic;
    constant key_table: matrix_key :=
        (("1", "2", "3", "A"),
         ("4", "5", "6", "B"),
         ("7", "8", "9", "C"),
         ("*", "0", "#", "D"));

    signal current_key: std_logic_vector(3 downto 0) := (others => '0');
    signal last_key: std_logic_vector(3 downto 0) := (others => '0');
    signal key_changed: std_logic := '0';

begin
    process (clk, reset)
    begin
        if (reset = '1') then
            counter <= (others => '0');
            pulse <= '0';
            current_key <= (others => '0');
            last_key <= (others => '0');
            key_changed <= '0';

        elsif (rising_edge(clk)) then
            if (enable = '1') then
                -- 检测矩阵键盘输入
                for i in 0 to 3 loop
                    if (matrix_col(i) = '0') then
                        current_key <= key_table(i) and matrix_row;
                        key_changed <= (current_key /= last_key);
                    end if;
                end loop;

                -- 如果键值发生变化，则控制步进电机
                if (key_changed = '1') then
                    if (current_key(0) = '1') then
                        direction <= '0';
                        counter <= (others => '0');
                        pulse <= '0';
                    elsif (current_key(1) = '1') then
                        direction <= '1';
                        counter <= (others => '0');
                        pulse <= '0';
                    elsif (current_key(2) = '1') then
                        if (counter < MAX_COUNT) then
                            counter <= counter + 1;
                        end if;
                    elsif (current_key(3) = '1') then
                        if (counter > 0) then
                            counter <= counter - 1;
                        end if;
                    end if;
                end if;

                -- 控制脉冲信号
                if (counter = MAX_COUNT) then
                    counter <= (others => '0');
                    pulse <= not pulse;
                else
                    counter <= counter + 1;
                end if;

                -- 控制步进信号
                if (pulse = '1') then
                    step <= '1';
                    wait for STEP_DELAY;
                    step <= '0';
                end if;
            end if;

            last_key <= current_key;
        end if;
    end process;

end Behavioral;

该代码实现了一个带有时钟、复位、矩阵键盘输入、使能、方向和步进信号的步进电机控制器。在时钟上升沿时，会检测矩阵键盘输入，如果键值发生变化，则会控制步进电机旋转方向和速度。控制脉冲信号和步进信号的方法与之前的例子相同。

这个代码实现的功能比较复杂，可以用于实现具有交互性的步进电机控制器。不过需要注意的是，由于矩阵键盘输入是离散的，控制步进电机的速度可能会有所不同。因此，在实际应用中，可能需要进行一定的调整和优化，以满足具体的需求。