FF / Latch和其他警告

时间：2012-03-06 22:31:58

标签： keyboard vhdl

任何人都可以帮我弄清楚我的VHDL代码有什么问题吗？这是代码：

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

entity main is
    port(
        --50MHz clock
        cp : in std_logic;
        --reset signal
        reset : in std_logic;
        --PS/2 data and clock lines
        ps2d, ps2c : in std_logic;
        --7-segment display segments
        segments : out std_logic_vector (7 downto 0);
        --anode control
        an : out std_logic_vector (3 downto 0);
        --data out to LEDs
        dout : out std_logic_vector (7 downto 0)
    );
end main;

architecture Behavioral of main is
    --data from keyboard entity (scancode)
    signal data : std_logic_vector (7 downto 0);
    --7 segments of display
    signal segReg, segNext : std_logic_vector (6 downto 0);
    signal tickDone : std_logic;
begin
    --just entity that reads PS/2 keyboard data
    --rx_done is tick (20 ns)
    S1: entity keyboard port map ( cp => cp, ps2d => ps2d, ps2c => ps2c,
                          rx_done => tickDone, dout => data);
    dout <= data;
    an <= "1110";
    segments(6 downto 0) <= segReg;
    --turn off dot
    segments(7) <= '1';
    process (cp, reset)
    begin
        if reset = '1' then
            segReg <= (others => '0');
        elsif rising_edge (cp) then
            segReg <= segNext;
        end if;
    end process;

    process (tickDone, segReg)
    begin
        segNext <= segReg;
        if tickDone = '1' then
            if data = x"16" then
                --number 1
                segNext <= "1001111";
            elsif data = x"1E" then
                --number 2
                segNext <= "0010010";
            elsif data = x"26" then
                --number 3
                segNext <= "0000110";
            elsif data = x"25" then
                --number 4
                segNext <= "1001100";
            else
                segNext <= "1111111";
            end if;
        end if;
    end process;

end Behavioral;

当我尝试合成它/生成编程文件时，我收到了这些警告：

WARNING:Xst:819 - "C:/VHDL_projekti/PS2K/main.vhd" line 48: The following signals are missing in the process sensitivity list:
WARNING:Xst:2734 - Property "use_dsp48" is not applicable for this technology.
WARNING:Xst:1710 - FF/Latch  <segReg_0> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_1> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_2> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_3> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_4> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_5> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1710 - FF/Latch  <segReg_0> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_1> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_2> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_3> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_4> (without init value) has a constant value of 0 in block <main>.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch  <segReg_5> (without init value) has a constant value of 0 in block <main>.
WARNING:Par:288 - The signal reset_IBUF has no load.  PAR will not attempt to route this signal.
WARNING:Par:283 - There are 1 loadless signals in this design. This design will cause Bitgen to issue DRC warnings.
WARNING:PhysDesignRules:367 - The signal <reset_IBUF> is incomplete. The signal

有人可以帮我吗？我一直在看代码，我没有看到任何错误，但显然我做错了。

1）“过程灵敏度列表中缺少以下信号”这可能是Xilinx ISE的错误吗？我不明白为什么我需要第48行的过程敏感性列表中的任何其他信号...

2）“由于其他FF / Latch修整，在块中具有恒定值0”好的，我做错了什么？我根本不想使用锁存器......

3）“信号reset_IBUF没有负载.PAR不会尝试路由此信号。”这是什么意思？我的复位信号有什么问题？为什么不完整？

此代码是我尝试将PS / 2键盘与Spartan 3入门板配合使用。实体“键盘”执行读取并且它正常工作（当我单独测试时，我在dout信号上得到正确的扫描码（我在LED上看到它））。 rx_done是tick（20ns），表示扫描码已成功读取。

所以我只是想知道我是否可以以某种方式识别扫描码（在我的第二个过程中，我正在比较数据信号并将正确的值与segNext信号相比较）并在7段显示器上显示。当我开始工作时，我将实现正确的行为（检测所有扫描代码，检查额外的密钥以及按键和按键事件）。

我不确定我是否需要描述其他内容，如果我这样做，请给我留言：）

感谢您的帮助!!!!

编辑：编辑的代码（将数据添加到敏感度列表，否则添加到if子句）： 

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

entity main is
    port(
        --50MHz clock
        cp : in std_logic;
        --reset signal
        reset : in std_logic;
        --PS/2 data and clock lines
        ps2d, ps2c : in std_logic;
        --7-segment display segments
        segments : out std_logic_vector (7 downto 0);
        --anode control
        an : out std_logic_vector (3 downto 0);
        --data out to LEDs
        dout : out std_logic_vector (7 downto 0)
    );
end main;

architecture Behavioral of main is
    --data from keyboard entity (scancode)
    signal data : std_logic_vector (7 downto 0);
    --7 segments of display
    signal segReg, segNext : std_logic_vector (6 downto 0);
    signal tickDone : std_logic;
begin
    --just entity that reads PS/2 keyboard data
    --rx_done is tick (20 ns)
    S1: entity keyboard port map ( cp => cp, ps2d => ps2d, ps2c => ps2c,
                          rx_done => tickDone, dout => data);
    dout <= data;
    an <= "1110";
    segments(6 downto 0) <= segReg;
    --turn off dot
    segments(7) <= '1';
    process (cp, reset)
    begin
        if reset = '1' then
            segReg <= (others => '0');
        elsif rising_edge (cp) then
            segReg <= segNext;
        end if;
    end process;

    process (tickDone, segReg, data)
    begin
        if tickDone = '1' then
            if data = x"16" then
                --number 1
                segNext <= "1001111";
            elsif data = x"1E" then
                --number 2
                segNext <= "0010010";
            elsif data = x"26" then
                --number 3
                segNext <= "0000110";
            elsif data = x"25" then
                --number 4
                segNext <= "1001100";
            else
                segNext <= "1111111";
            end if;
        else
            segNext <= segReg;
        end if;
    end process;

end Behavioral;

不幸的是，经过这些编辑后，我仍然有这样的警告：

WARNING:Xst:1710 - FF/Latch <segReg_0> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_1> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_2> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_3> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_4> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_5> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_6> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1710 - FF/Latch <segReg_0> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_1> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_2> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_3> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_4> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Xst:1895 - Due to other FF/Latch trimming, FF/Latch <segReg_5> (without init value) has a constant value of 0 in block <main>. This FF/Latch will be trimmed during the optimization process.
WARNING:Par:288 - The signal reset_IBUF has no load.  PAR will not attempt to route this signal.
WARNING:Par:283 - There are 1 loadless signals in this design. This design will cause Bitgen to issue DRC warnings.

3 个答案:

答案 0 :(得分：3)

在您的组合过程中，您正在阅读tickDone，segReg和data。灵敏度列表中缺少后者，导致锁存。

另外，请勿使用STD_LOGIC_ARITH或STD_LOGIC_UNSIGNED。它们没有标准化，有几个问题。 http://parallelpoints.com/node/3

答案 1 :(得分：1)

您的第二个过程似乎是尝试使用tickDone作为时钟信号，但您没有正确使用它（即：如果rising_edge（tickDone）或类似），那么您创建的是锁存器而不是触发器（如果tickDone = '1'）。使用锁存器，当tickDone为高电平时，输出取决于数据信号的状态，而不在灵敏度列表中。最后，使用敏感列表中的segReg，编写代码的方式，您将segReg异步分配给segNext。

您是否忘记使用cp信号作为时钟在if语句中将所有内容包装在第二个进程中？你所写的内容会更有意义......

答案 2 :(得分：1)

  

2）“由于其他FF / Latch修整，块中的常量值为0”OK，    我究竟做错了什么 ？我根本不想使用锁存器......

这告诉你这些存储元素是由常量驱动的，而不是它们是锁存器。你有没有模拟过这个？

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