State_Machine VHDL代码，请你检查它为什么不起作用！它合成好

Question

我有一个任务写VHDL状态机来控制一个小型的内置MC（由4个触发器，2 MUX4to1，MUX1to4，ROM，ALU，Inport组成）。

我写了不同的代码，并尝试了几种方法，但模拟它显示没有结果，我得到'U'的结果。

下面的代码，请检查我可能错过的明显错误。 我认为问题在于stjatemachine不会通过状态进行转换，也不会在每个状态中执行代码。

---------------------------------------------------------------------------------- 
-- Company: 
-- Engineer: 
-- 
-- Create Date: 07:48:47 10/26/2014 
-- Design Name: 
-- Module Name: STATE_MACHINE - Behavioral 
-- Project Name: 
-- Target Devices: 
-- Tool versions: 
-- Description: 
-- 
-- Dependencies: 
-- 
-- Revision: 
-- Revision 0.01 - File Created 
-- Additional Comments: 
-- 
---------------------------------------------------------------------------------- 
library IEEE; 
use IEEE.STD_LOGIC_1164.ALL; 
use IEEE.STD_LOGIC_UNSIGNED.ALL;-- Uncomment the following library declaration if using 
-- arithmetic functions with Signed or Unsigned values 
--use IEEE.NUMERIC_STD.ALL; 

-- Uncomment the following library declaration if instantiating 
-- any Xilinx primitives in this code. 
--library UNISIM; 
--use UNISIM.VComponents.all; 

entity STATE_MACHINE is 
port (

     --General Ports 
     CLK : in STD_LOGIC; 
     Re_Run_Programme : in STD_LOGIC; 

     --Process A parts 
     Programme_Start : in STD_LOGIC; 
     Data_From_ROM : in STD_LOGIC_VECTOR(7 downto 0); 
     ADDR_To_ROM : out STD_LOGIC_VECTOR (5 downto 0); 
     Programme_Status: out STD_LOGIC; 
     EN_OUT : out STD_LOGIC; 

     --Process B Part 


     --Process C Parts 

     MUX_FF_Select : out STD_LOGIC_VECTOR (1 downto 0); 

     MUX1_Select : out STD_LOGIC_VECTOR(1 downto 0); 
     MUX2_Select : out STD_LOGIC_VECTOR(1 downto 0); 
     ALU_Select : out STD_LOGIC_VECTOR(1 downto 0); 

     EN_A_Ports : out STD_LOGIC; 
     EN_B_Ports : out STD_LOGIC; 

     BUS_Select : out STD_LOGIC_VECTOR (1 downto 0); 
     Reset  : out STD_LOGIC 



    ); 
end STATE_MACHINE; 

architecture Behavioral of STATE_MACHINE is 

type State_Type is (State_A,State_B,State_C,State_D); 
signal State,Next_State : State_Type; 

signal Counter : STD_LOGIC_VECTOR(5 downto 0); 

--signal MO_A : STD_LOGIC; 
--signal MO_B : STD_LOGIC; 
--signal MO_C : STD_LOGIC; 
--signal MO_D : STD_LOGIC; 

signal FF_Instruction : STD_LOGIC_VECTOR (7 downto 0);   -- 00 
signal MUX_ALU_Instruction : STD_LOGIC_VECTOR (7 downto 0);   -- 01 
signal BUS_A_B_Ports_Instruction : STD_LOGIC_VECTOR (7 downto 0); -- 10 
signal Reset_Instruction : STD_LOGIC_VECTOR (7 downto 0); 

signal FF_Path : STD_LOGIC; 
signal MUX_ALU_Path : STD_LOGIC; 
signal BUS_A_B_Ports_Path : STD_LOGIC; 
signal Reset_Path : STD_LOGIC; 

signal EN_OUT_reg : STD_LOGIC; 

--signal Next_Call : STD_LOGIC_VECTOR (7 downto 0); 
signal Instruction_Finder : STD_LOGIC_VECTOR (7 downto 0); 
signal Instruction_Identifier : STD_LOGIC_VECTOR(7 downto 0); 
signal Instruction : STD_LOGIC_VECTOR(7 downto 0); 
signal Call_Next_Instruction : STD_LOGIC_VECTOR(5 downto 0); 


begin 



FF_Instruction  <= "00000000"; 
MUX_ALU_Instruction  <= "01000000"; 
BUS_A_B_Ports_Instruction <= "10000000"; 
Reset_Instruction   <= "11000000"; 

Instruction_Finder <= "11000000"; 

Counter <= "000000"; 
Call_Next_Instruction <= "000000"; 


--Re Run the programme 
Process(CLK) 
begin 
    if rising_edge(CLK) then 
     if (Re_Run_Programme = '1') then 
      State <= State_A; 
--   MO_A <= '0'; 
      else 
      State <= Next_State; 
     end if; 
    end if; 
end Process; 

--next state 
Process(CLK,State) 
begin 

Next_State <= State; 

case State is 


--#### STATE A ##### 
    when State_A => 

    --if falling_edge(CLK) then 

      ADDR_To_ROM <= Call_Next_Instruction; 
      --EN_OUT <= '1'; 
      --if falling_edge (CLK) then 
       --Instruction <= DATA_From_ROM; 
      --end if; 
    Next_State <= State_B; 

    --end if; 


--#### STATE B ##### 
    when State_B => 
    EN_OUT <= '1'; 
       Instruction <= DATA_From_ROM; 

     Instruction_Identifier <= (Instruction and Instruction_Finder); 
     case (Instruction_Identifier) is 
      when "00000000" => FF_Path <= '1'; 
      when "01000000" => MUX_ALU_Path <= '1'; 
      when "10000000" => BUS_A_B_Ports_Path <= '1'; 
      when "11000000" => Reset_Path <= '1'; 
      when others => null; 
     end case; 
     Next_State <= State_C after 40ns; 

--#### STATE C##### 

    when State_C => 

     --######## 
     if ((FF_Path = '1') and (Counter = 2)) then 
      MUX_FF_Select <= "00"; 
     end if; 
     if ((FF_Path = '1') and (Counter = 4)) then 
      MUX_FF_Select <= "00" after 20ns; 
     end if; 

     --######## 

     if (falling_edge(CLK) and (MUX_ALU_Path = '1')) then 
      MUX1_Select <= "00"; 
      MUX2_Select <= "00"; 
     end if; 

     --######## 

     if (rising_edge(CLK) and BUS_A_B_Ports_Path = '1') then 
      if Counter = 1 then 
       BUS_Select <= "01"; 
      end if; 
      if Counter = 3 then 
       BUS_Select <= "10"; 
      end if; 
      EN_A_Ports <= '1'; 
      EN_B_Ports <= '1'; 
     end if; 

     --######## 

     if (rising_edge(CLK) and Reset_Path = '1') then 
     Reset <= '1'; 
     end if; 

     Next_State <= State_D after 60ns; 

--#### STATE D ##### 

    when State_D => 


     EN_OUT <= '0'; 
     Counter <= Counter + 1; 

     if Counter > 5 then  
      Next_State <= State_D; 
     end if; 

     Call_Next_Instruction <= Counter; 

     Next_State <= State_A; 


    end case; 
end process; 


end Behavioral; 

GitHub的链接代码：https://github.com/quasarMind/StateMachine.git

Answer 1

除了由比尔·林奇和布赖恩·德拉蒙德意见处理合成的资格有原因的模型得到所有“U的似乎周围多个驱动器旋转的 Instruction_Finder，Counter和Call_Next_Instruction 。一个司机是初始化的另一个提供所有的'U's，这两个解决所有的'U's。

为了模拟，看看你的状态机实际上不会（和回避合成的问题）的目的，在其声明中这三个信号设置的默认值，并注释掉额外的并行信号赋值语句，如：

signal Counter : STD_LOGIC_VECTOR(5 downto 0) := (others => '0'); 

signal Instruction_Finder : STD_LOGIC_VECTOR (7 downto 0) := "11000000"; 

signal Call_Next_Instruction : STD_LOGIC_VECTOR(5 downto 0) := (others => '0'); 


-- Instruction_Finder <= "11000000"; 
-- Counter <= "000000"; 
-- Call_Next_Instruction <= "000000"; 

大多数综合供应商会遵守FPGA目标信号的默认值，否则您可以添加重置。