VHDL多源/悬挂信号错误xst:528

Question

嘿，伙计们，我正在尝试用VHDL语言实现一个32x6RAM，我发誓一切看起来都很好，但我似乎找不出为什么当我试图创建S=>AD(0) to S=>AD(31)...Can时，我得到了一个悬空信号/多源错误，有人能帮我指出我在代码中可能忘记了什么吗？

Code:
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.STD_LOGIC_ARITH.ALL;
use IEEE.STD_LOGIC_UNSIGNED.ALL;

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

entity mm32by6RAM is
    Port ( OE   : in    STD_LOGIC;
           CS   : in    STD_LOGIC;
           RW   : in    STD_LOGIC;
           A    : in    STD_LOGIC_VECTOR (4 downto 0);
           D    : out   STD_LOGIC_VECTOR (5 downto 0));
end mm32by6RAM;

architecture Behavioral of mm32by6RAM is

COMPONENT mm5to32Decoder
    Port ( A    : in    STD_LOGIC_VECTOR (4 downto 0);
           OEB : in     STD_LOGIC;
           Z    : out   STD_LOGIC_VECTOR (31 downto 0));
end COMPONENT;


COMPONENT mm1by6RAM
    Port ( I : in   STD_LOGIC_VECTOR (5 downto 0);
           W : in   STD_LOGIC;
           R : in   STD_LOGIC;
           S : in   STD_LOGIC;
              D : out   STD_LOGIC_VECTOR (5 downto 0));
end COMPONENT;


COMPONENT mmOutputBuffer
    Port ( B    : in    STD_LOGIC_VECTOR(5 downto 0);
           OE   : in    STD_LOGIC;
           D    : out   STD_LOGIC_VECTOR (5 downto 0));
end COMPONENT;


COMPONENT mm3NOR 
    Port ( A : in   STD_LOGIC;
           B : in   STD_LOGIC;
           C : in   STD_LOGIC;
           Z : out      STD_LOGIC);
end COMPONENT;


COMPONENT mmINVERT
    Port ( a : in       STD_LOGIC;
           z : out      STD_LOGIC);
end COMPONENT;


SIGNAL RWnot        :   STD_LOGIC;
SIGNAL N                :   STD_LOGIC;
SIGNAL OB           :   STD_LOGIC_VECTOR (5 downto 0);
SIGNAL AD           :   STD_LOGIC_VECTOR (31 downto 0);
SIGNAL Ram          :   STD_LOGIC_VECTOR (5 downto 0);

begin

gate1       :   mmINVERT            PORT MAP    (a=>RW,     z=>RWnot);
gate2       :   mm3NOR          PORT MAP    (A=>OE,     B=>CS,      C=>RWnot,   Z=>N);
gate3       :   mmOutputBuffer  PORT MAP    (B=>Ram, OE=>N,         D=>OB);
gate4       :   mm5to32Decoder  PORT MAP    (A=>A,  OEB=>CS,        Z=>AD);

gate5       :   mm1by6RAM       PORT MAP    (I=>OB,     W=>RWnot,   R=>RW,  S=>AD(0),   D=>Ram);
gate6       :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(1),   D=>Ram);
--gate7     :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(2),   D=>Ram);
--gate8     :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(3),   D=>Ram);
--gate9     :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(4),   D=>Ram);
--gate10    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(5),   D=>Ram);
--gate11    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(6),   D=>Ram);
--gate12    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(7),   D=>Ram);
--gate13    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(8),   D=>Ram);
--gate14    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(9),   D=>Ram);
--gate15    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(10),  D=>Ram);
--gate16    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(11),  D=>Ram);
--gate17    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(12),  D=>Ram);
--gate18    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(13),  D=>Ram);
--gate19    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(14),  D=>Ram);
--gate20    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(15),  D=>Ram);
--gate21    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(16),  D=>Ram);
--gate22    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(17),  D=>Ram);
--gate23    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(18),  D=>Ram);
--gate24    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(19),  D=>Ram);
--gate25    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(20),  D=>Ram);
--gate26    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(21),  D=>Ram);
--gate27    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(22),  D=>Ram);
--gate28    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(23),  D=>Ram);
--gate29    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(24),  D=>Ram);
--gate30    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(25),  D=>Ram);
--gate31    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(26),  D=>Ram);
--gate32    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(27),  D=>Ram);
--gate33    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(28),  D=>Ram);
--gate34    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(29),  D=>Ram);
--gate35    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(30),  D=>Ram);
--gate36    :   mm1by6RAM       PORT MAP    (I=>OB, W=>RWnot,   R=>RW,  S=>AD(31),  D=>Ram);



end Behavioral;

以下是它应该遵循的设计原理图：

http://www.cse.psu.edu/~kyusun/class/cmpen471/12f/hw/pj4/ram32x6.gif

谢谢你们！

Answer 1

您的每个mm1by6RAM都需要输出到一个唯一的信号。然后使用选择信号AD，您可以选择其中哪一个是正确的。

该工具不知道如何为您完成此操作。

你需要这样的东西：

Ram <= Output_from_gate0 when AD(0) = '1' else
       Output_from_gate1 when AD(1) = '1' else
       Output_from_gate2 when AD(2) = '1' else
       ...