用Mealy机类型写出控制ADC0809采样的状态机的vhdl代码

Mealy型状态机通常用于描述数据流依赖于当前状态的系统，例如ADC0809这样的模拟数字转换器（ADC）。在VHDL（VHSIC Hardware Description Language）中，我们创建一个状态机模块来控制ADC0809的不同步骤，如启动、读取输入通道、等待转换完成等。这里是一个简化的示例：

library IEEE;
use IEEE.STD_LOGIC_1164.ALL;

entity ADC0809_SeqCtrl is
   Port ( 
      Start : in STD_LOGIC;
      DataIn : in STD_LOGIC_VECTOR(7 downto 0);
      Address : in STD_LOGIC_VECTOR(3 downto 0);
      Clock : in STD_LOGIC;
      Done : out STD_LOGIC;
      State : out STD_LOGIC_VECTOR(1 downto 0)
   );
end ADC0809_SeqCtrl;

architecture Behavioral of ADC0809_SeqCtrl is
   type State_Type is (Idle, Convert);
   signal Current_State : State_Type;
begin
   -- 状态转移逻辑
   process(Clock)
   begin
      if rising_edge(Clock) then
         case Current_State is
            when Idle =>
               if Start = '1' then
                  Current_State <= Convert;
               else
                  State <= "00"; -- 等待开始信号
               end if;
            when Convert =>
               if ADC0809_ReadAck = '1' then -- 假设ADC0809有个Read Ack信号
                  if Address = "0000" then
                     State <= "01";
                  elsif Address = "0001" then
                     -- 处理下一个通道
                     -- ...省略处理细节...
                  end if;
               else
                  State <= "10"; -- 转换未完成，保持读取状态
               end if;
         end case;
         
         -- 更新状态输出
         if Current_State /= Previous_State then
            State <= Current_State;
            if Current_State = Convert and ADC0809_TransferDone = '1' then
               Done <= '1'; -- 转换完成标志
            else
               Done <= '0';
            end if;
      end if;
   end process;
   
   Previous_State <= Current_State; -- 更新上一状态
end Behavioral;

-- 其他假设信号和辅助函数省略...
--