写一份vhdl代码，描述用上位机通过串口控制6个led等的代码

好的，以下是VHDL代码的示例：

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity LED_control is
    port (
        clk     : in  std_logic;
        rst     : in  std_logic;
        data_in : in  std_logic_vector(7 downto 0);
        enable  : in  std_logic;
        led_out : out std_logic_vector(5 downto 0)
    );
end entity;

architecture behavioral of LED_control is
    signal buffer    : std_logic_vector(47 downto 0);
    signal counter   : unsigned(5 downto 0) := (others => '0');
    signal data_sync : std_logic_vector(7 downto 0);
    signal interrupt : std_logic := '0';
begin
    process(clk, rst)
    begin
        if rst = '1' then
            buffer <= (others => '0');
            counter <= (others => '0');
            data_sync <= (others => '0');
            interrupt <= '0';
        elsif rising_edge(clk) then
            if enable = '1' then
                if interrupt = '1' then
                    interrupt <= '0';
                    if counter = 47 then
                        counter <= (others => '0');
                    else
                        counter <= counter + 1;
                    end if;
                    buffer(counter * 8 + 7 downto counter * 8) <= data_sync;
                end if;
            end if;
        end if;
    end process;

    process(clk, rst)
    begin
        if rst = '1' then
            led_out <= (others => '0');
        elsif rising_edge(clk) then
            if enable = '1' then
                if interrupt = '1' then
                    led_out <= buffer(5 downto 0);
                end if;
            end if;
        end if;
    end process;

    process(clk, rst)
    begin
        if rst = '1' then
            data_sync <= (others => '0');
        elsif rising_edge(clk) then
            if enable = '1' then
                if interrupt = '0' then
                    data_sync <= data_in;
                    interrupt <= '1';
                end if;
            end if;
        end if;
    end process;
end behavioral;

这个代码描述了一个能够通过串口控制6个LED灯的电路。具体实现方式是：上位机通过串口将控制数据送入FPGA芯片，在FPGA上触发一个中断，在中断服务程序中将控制数据存入一个缓冲区，并依据计数器将其存入LED灯的对应输出端口。这个代码的基本原理是用VHDL描述出一个状态机，通过状态机控制LED的输出状态，实现LED显示效果的控制。