写一个数字是脉宽测量电路VHDL代码

以下是一个数字脉宽测量电路的 VHDL 代码示例：

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.NUMERIC_STD.ALL;

entity pulse_width_measure is
    Port ( clk : in std_logic;
           in_pulse : in std_logic;
           reset : in std_logic;
           out_width : out integer range 0 to 2**8-1);
end pulse_width_measure;

architecture Behavioral of pulse_width_measure is
    signal count : integer range 0 to 2**8-1;
    signal pulse_start : std_logic;
begin
    process (clk, reset)
    begin
        if reset = '1' then
            count <= 0;
            pulse_start <= '0';
            out_width <= 0;
        elsif rising_edge(clk) then
            if in_pulse = '1' and pulse_start = '0' then
                pulse_start <= '1';
                count <= 0;
            elsif in_pulse = '0' and pulse_start = '1' then
                pulse_start <= '0';
                out_width <= count;
            end if;
            if pulse_start = '1' then
                count <= count + 1;
            end if;
        end if;
    end process;
end Behavioral;

该代码使用一个计数器和一个信号标记输入脉冲的开始时间。当输入脉冲上升沿到来时，将标记为 '1' 并将计数器重置为 0。当输入脉冲下降沿到来时，将标记为 '0' 并将计数器的值作为输出宽度。如果输入脉冲持续时间超过计数器的范围，则输出将被截断。