VHDL警告XST：1293 FF /锁存器具有0
问题描述：
没有在互联网上回答的恒定值我工作，因为我在VHDL初学者。VHDL警告XST：1293 FF /锁存器具有0
我正在与按钮和LED VHDL密码界面。 我的程序按预期正确模拟。
基本上，我想的LED进入错误密码时，眨眼，但输入正确的密码时，连续发光。你可以看到，这在仿真中起作用。
SIMULATION IMAGE （在模拟第一输入错误口令，然后正确的密码）
虽然合成，以下主要发生报警：
Optimizing unit <safehouse> ...
WARNING:Xst:1293 - FF/Latch <entry_pass.ncount_6> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_7> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
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.
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VHDL代码是：
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity safehouse is
Port (keyled : out STD_LOGIC_VECTOR(0 TO 4);
keypad : in STD_LOGIC_VECTOR(0 to 7);
clk : in STD_LOGIC);
end safehouse;
architecture safehouse of safehouse is
signal temp : std_logic_vector(0 to 7) := "00000000";
begin
entry_pass: process(clk,keypad,temp)
type integer_vector is array (0 to 3) of integer;
variable i : integer := 0;
constant passoriginal : integer_vector := (2,5,2,6);
variable passcode : integer_vector := (0,0,0,0);
variable dcount : integer := 0;
variable ncount : integer := 0;
begin
if (rising_edge(clk)) then
keyled(4) <= '1';
if i < 4 then
keyled(0) <= '1';
if (temp /= keypad) then
case keypad is
when "10001000" =>
passcode(i) := 1;
keyled(i+1) <= '1';
i := i + 1;
when "10000100" =>
passcode(i) := 2;
keyled(i+1) <= '1';
i := i + 1;
when "10000010" =>
passcode(i) := 3;
keyled(i+1) <= '1';
i := i + 1;
when "10000001" =>
passcode(i) := 10;
keyled(i+1) <= '1';
i := i + 1;
when "01001000" =>
passcode(i) := 4;
keyled(i+1) <= '1';
i := i + 1;
when "01000100" =>
passcode(i) := 5;
keyled(i+1) <= '1';
i := i + 1;
when "01000010" =>
passcode(i) := 6;
keyled(i+1) <= '1';
i := i + 1;
when "01000001" =>
passcode(i) := 11;
keyled(i+1) <= '1';
i := i + 1;
when "00101000" =>
passcode(i) := 7;
keyled(i+1) <= '1';
i := i + 1;
when "00100100" =>
passcode(i) := 8;
keyled(i+1) <= '1';
i := i + 1;
when "00100010" =>
passcode(i) := 9;
keyled(i+1) <= '1';
i := i + 1;
when "00100001" =>
passcode(i) := 12;
keyled(i+1) <= '1';
i := i + 1;
when "00011000" =>
passcode(i) := 14;
keyled(i+1) <= '1';
i := i + 1;
when "00010100" =>
passcode(i) := 0;
keyled(i+1) <= '1';
i := i + 1;
when "00010010" =>
passcode(i) := 15;
keyled(i+1) <= '1';
i := i + 1;
when "00010001" =>
passcode(i) := 13;
keyled(i+1) <= '1';
i := i + 1;
when others =>
keyled(4) <= '1';
end case;
temp <= keypad;
end if;
else
if passcode = passoriginal then
dcount := dcount + 1;
if dcount >= 50000000 then
keyled <= ('1','1','1','1','1');
dcount := 1;
ncount := ncount + 1;
if ncount >= 8 then
i := 0;
passcode := (0,0,0,0);
keyled <= ('0','0','0','0','1');
ncount := 1;
end if;
end if;
else
dcount := dcount + 1;
if dcount >= 50000000 then
if (ncount rem 2) = 0 then
keyled <= ('1','1','1','1','1');
else
keyled <= ('0','0','0','0','1');
end if;
dcount := 1;
ncount := ncount + 1;
if ncount >= 8 then
i := 0;
keyled <= ('1','0','0','0','1');
ncount := 1;
end if;
end if;
end if;
end if;
end if;
end process;
end safehouse;
我知道变量ncount正在修剪但我需要它。 可变NCOUNT用于创建的使用可变DCOUNT其用来创建的0.5秒的延迟4秒的延迟。 无变量ncount我无法创建延迟4秒。
完整的警告是：
WARNING:Xst:1710 - FF/Latch <keyled_4> (without init value) has a constant value of 1 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
Optimizing unit <safehouse> ...
WARNING:Xst:1293 - FF/Latch <entry_pass.ncount_6> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_7> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_8> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_11> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_9> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_10> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_14> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_12> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_13> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_17> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_15> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_16> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_20> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_18> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_19> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_23> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_21> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_22> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_26> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_24> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_25> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_29> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_27> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_28> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_30> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_31> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.dcount_26> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.dcount_29> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.dcount_27> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.dcount_28> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.dcount_30> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.dcount_31> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_3> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_4> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_5> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_6> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_7> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_8> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_9> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_10> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_11> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_12> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_13> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_14> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_15> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_16> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_17> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_18> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_19> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_20> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_21> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_22> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_23> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_24> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_25> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_26> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_27> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_28> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_29> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_30> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.i_31> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_4> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_3> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1896 - Due to other FF/Latch trimming, FF/Latch <entry_pass.ncount_5> has a constant value of 0 in block <safehouse>. This FF/Latch will be trimmed during the optimization process.
我使用的FPGA开发板是：赛灵思Spartan 6 XC6SLX9 TQG144。 请帮帮我。
答
我自己解决了这个问题。谢谢大家。
与信号替换变量和添加约束（其范围的值）
添加约束变量可以解决这个问题。
我的程序能够在不改变的变量（如我，DCOUNT，NCOUNT）的信号，让我觉得这个问题是的范围如果声明后的任何警告合成的事实。由于对变量的赋值操作在嵌套的if语句内部，因此合成器未找到所需范围内的变量值的变化并假定它具有恒定值。信号的范围比变量好得多。
然而，正如我初学者我上述的原因可能是错误的。但这里是解决我的问题的代码。
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
entity safehouse is
Port (keyled : out STD_LOGIC_VECTOR(0 TO 4);
keypad : in STD_LOGIC_VECTOR(0 to 7);
clk : in STD_LOGIC);
end safehouse;
architecture safehouse of safehouse is
signal temp : std_logic_vector(0 to 7) := "00000000";
signal dcount : integer range 0 to 100000000 := 0;
signal ncount : integer range 0 to 10 := 0;
signal i : integer range 0 to 5;
begin
entry_pass: process(clk,keypad,temp,dcount,ncount,i)
type integer_vector is array (0 to 3) of integer;
constant passoriginal : integer_vector := (2,5,2,6);
variable passcode : integer_vector := (0,0,0,0);
begin
if (rising_edge(clk)) then
keyled(4) <= '1';
if i < 4 then
keyled(0) <= '1';
if (temp /= keypad) then
case keypad is
when "10001000" =>
passcode(i) := 1;
keyled(i+1) <= '1';
i <= i + 1;
when "10000100" =>
passcode(i) := 2;
keyled(i+1) <= '1';
i <= i + 1;
when "10000010" =>
passcode(i) := 3;
keyled(i+1) <= '1';
i <= i + 1;
when "10000001" =>
passcode(i) := 10;
keyled(i+1) <= '1';
i <= i + 1;
when "01001000" =>
passcode(i) := 4;
keyled(i+1) <= '1';
i <= i + 1;
when "01000100" =>
passcode(i) := 5;
keyled(i+1) <= '1';
i <= i + 1;
when "01000010" =>
passcode(i) := 6;
keyled(i+1) <= '1';
i <= i + 1;
when "01000001" =>
passcode(i) := 11;
keyled(i+1) <= '1';
i <= i + 1;
when "00101000" =>
passcode(i) := 7;
keyled(i+1) <= '1';
i <= i + 1;
when "00100100" =>
passcode(i) := 8;
keyled(i+1) <= '1';
i <= i + 1;
when "00100010" =>
passcode(i) := 9;
keyled(i+1) <= '1';
i <= i + 1;
when "00100001" =>
passcode(i) := 12;
keyled(i+1) <= '1';
i <= i + 1;
when "00011000" =>
passcode(i) := 14;
keyled(i+1) <= '1';
i <= i + 1;
when "00010100" =>
passcode(i) := 0;
keyled(i+1) <= '1';
i <= i + 1;
when "00010010" =>
passcode(i) := 15;
keyled(i+1) <= '1';
i <= i + 1;
when "00010001" =>
passcode(i) := 13;
keyled(i+1) <= '1';
i <= i + 1;
when others =>
keyled(4) <= '1';
end case;
temp <= keypad;
end if;
else
if passcode = passoriginal then
dcount <= dcount + 1;
if dcount >= 50000000 then
keyled <= ('1','1','1','1','1');
dcount <= 1;
ncount <= ncount + 1;
if ncount >= 8 then
i <= 0;
passcode := (0,0,0,0);
keyled <= ('0','0','0','0','1');
ncount <= 1;
end if;
end if;
else
dcount <= dcount + 1;
if dcount >= 50000000 then
if (ncount rem 2) = 0 then
keyled <= ('1','1','1','1','1');
else
keyled <= ('0','0','0','0','1');
end if;
dcount <= 1;
ncount <= ncount + 1;
if ncount >= 8 then
i <= 0;
keyled <= ('1','0','0','0','1');
ncount <= 1;
end if;
end if;
end if;
end if;
end if;
end process;
end safehouse;
这是我的这个网站上的第一个问题。我会鼓励每一个回应。我有一个很好的经验。谢谢。
+0
你为什么警告消失的推理似乎不正确。这不是因为它们是信号，而是因为它们受到限制，你可以对原始变量进行处理。 – user1155120
+0
我认为你是对的。 –
的这些第一金属块是从声明的东西作为一个整数，而不是一个限制整数。 entry_pass.ncount只有1到8的范围。你明显不需要你表达的代码中的其余部分。想想二进制/数字逻辑以及数字的意思。一个无约束的整数在综合中被详细描述为32位二进制并表示一个二进制补码值。如果你只使用它的四个位，你会看到其余的修剪。 – user1155120
[VHDL综合 - FF/Latch常量值]的可能重复（https://*.com/questions/16087307/vhdl-synthesis-ff-latch-constant-value） – user1155120
Thankyou，@ user1155120您的评论，代码在我发布的答案解决了我的问题。但是，您可能希望通过代码背后的原因来启发我们。 –