FPGA程序如下：

LIBRARY IEEE;
USE IEEE.std_logic_1164.ALL;

ENTITY fpga_test IS
PORT(
    clk_in :IN STD_LOGIC;   --fpga输入时钟，10M
    SWOEn  :OUT STD_LOGIC;  --开关量输入输出使能
    SWDir  :OUT STD_LOGIC;  --开关量输入输出方向选择信号
    SW     :INOUT STD_LOGIC_VECTOR(7 DOWNTO 0); --开关量输入输出端口
--以下端口先定义，但实际上并未作用
    DATA   :INOUT STD_LOGIC_VECTOR(15 DOWNTO 0);--FPGA与44B0连接的数据总线
    ADDR   :IN STD_LOGIC_VECTOR(9 DOWNTO 1);--FPGA与44B0连接的地址总线
    nRESET :IN STD_LOGIC;--FPGA复位信号
    KEY_INT:OUT STD_LOGIC;--按键扫描中断
    COUNT_INT:OUT STD_LOGIC;--计数中断
    nGCS4  :IN STD_LOGIC;--FPGA片选信号
    nGCS1  :IN STD_LOGIC;--NAND FLASH片选信号
    nWE    :IN STD_LOGIC;--FPGA写允许信号
    nOE    :IN STD_LOGIC;--FPGA读允许信号
    NFRE   :OUT STD_LOGIC;--NAND FLASH读允许信号
    NFWE   :OUT STD_LOGIC--NAND FLASH写允许信号
);
END fpga_test;

ARCHITECTURE behavier OF fpga_test IS
BEGIN
--由于KEY_INT、COUNT_INT这两根中断线暂时不使用，先把它们定义为高阻，
--避免状态不定，导致系统工作紊乱
      KEY_INT<='Z';
      COUNT_INT<='Z';

      NFRE <= nOE OR nGCS1;--产生NAND FLASH读允许信号
      NFWE <= nWE OR nGCS1;--产生NAND FLASH写允许信号

--    DATA<="ZZZZZZZZZZZZZZZZ";
  
----------以下语句起测试作用
    SWOEn <= '0';--74LVC245A输入输出使能
    SWDir <= '1';--设置输入输入方向：输出
    --SW <= clk_in;--我想让每个SWIO都输出10M脉冲，想测试一下fpga是否能正常工作  
 SW(0) <= clk_in;
    SW(1) <= clk_in;
 SW(2) <= clk_in;
 SW(3) <= clk_in;
 SW(4) <= clk_in;
 SW(5) <= clk_in;
 SW(6) <= clk_in;
 SW(7) <= clk_in;
END behavier;

编译后出现如下警告：
1、Warning: TRI or OPNDRN buffers permanently enabled
 Warning: Node "comb~0"
 Warning: Node "comb~1"
 Warning: Node "comb~2"
 Warning: Node "comb~3"
 Warning: Node "comb~4"
 Warning: Node "comb~5"
 Warning: Node "comb~6"
 Warning: Node "comb~7"
请问这些是什么意思？我在程序里并没有定义comb~0等端口啊?

2、Warning: Output pins are stuck at VCC or GND
 Warning: Pin "SWOEn" stuck at GND
 Warning: Pin "SWDir" stuck at VCC
这个警告估计是因为我在程序里把SWOEn赋值为0,SWDir赋值为1，不过现在不明白这个VCC究竟是多少？因为cyclone ep1c3t144有两种电压1.5(

内核)和3.3(i/o)，我觉得应该是3.3?

3、Warning: Design contains 11 input pin(s) that do not drive logic
 Warning: No output dependent on input pin "ADDR[1]"
 Warning: No output dependent on input pin "ADDR[2]"
 Warning: No output dependent on input pin "ADDR[3]"
 Warning: No output dependent on input pin "ADDR[4]"
 Warning: No output dependent on input pin "ADDR[5]"
 Warning: No output dependent on input pin "ADDR[6]"
 Warning: No output dependent on input pin "ADDR[7]"
 Warning: No output dependent on input pin "ADDR[8]"
 Warning: No output dependent on input pin "ADDR[9]"
 Warning: No output dependent on input pin "nRESET"
 Warning: No output dependent on input pin "nGCS4"
这些警告是不是因为我在程序中把端口信号ADDR、nRESET、nGCS4定义为输入，但是在程序中却没有使用的原因?

4、Warning: The following 24 pins have no output enable or a GND or VCC output enable - later changes to this connectivity

may change fitting results
 Info: Pin DATA[0] has a permanently enabled output enable
 Info: Pin DATA[1] has a permanently enabled output enable
 Info: Pin DATA[2] has a permanently enabled output enable
 Info: Pin DATA[3] has a permanently enabled output enable
 Info: Pin DATA[4] has a permanently enabled output enable
 Info: Pin DATA[5] has a permanently enabled output enable
 Info: Pin DATA[6] has a permanently enabled output enable
 Info: Pin DATA[7] has a permanently enabled output enable
 Info: Pin DATA[8] has a permanently enabled output enable
 Info: Pin DATA[9] has a permanently enabled output enable
 Info: Pin DATA[10] has a permanently enabled output enable
 Info: Pin DATA[11] has a permanently enabled output enable
 Info: Pin DATA[12] has a permanently enabled output enable
 Info: Pin DATA[13] has a permanently enabled output enable
 Info: Pin DATA[14] has a permanently enabled output enable
 Info: Pin DATA[15] has a permanently enabled output enable
 Info: Pin SW[0] has a permanently enabled output enable
 Info: Pin SW[1] has a permanently enabled output enable
 Info: Pin SW[2] has a permanently enabled output enable
 Info: Pin SW[3] has a permanently enabled output enable
 Info: Pin SW[4] has a permanently enabled output enable
 Info: Pin SW[5] has a permanently enabled output enable
 Info: Pin SW[6] has a permanently enabled output enable
 Info: Pin SW[7] has a permanently enabled output enable
这些警告是什么原因?

5、Warning: The following 20 pins have nothing, GND, or VCC driving datain port -- changes to this connectivity may change

fitting results
 Info: Pin SWOEn has GND driving its datain port
 Info: Pin SWDir has VCC driving its datain port
 Info: Pin KEY_INT has VCC driving its datain port--这里，我把KEY_INT赋值为Z啊？怎么这里把它拉高至VCC?
 Info: Pin COUNT_INT has VCC driving its datain port
 Info: Pin DATA[0] has VCC driving its datain port--这里我把DATA赋值为Z啊？怎么这里说把它拉高至VCC?
 Info: Pin DATA[1] has VCC driving its datain port
 Info: Pin DATA[2] has VCC driving its datain port
 Info: Pin DATA[3] has VCC driving its datain port
 Info: Pin DATA[4] has VCC driving its datain port
 Info: Pin DATA[5] has VCC driving its datain port
 Info: Pin DATA[6] has VCC driving its datain port
 Info: Pin DATA[7] has VCC driving its datain port
 Info: Pin DATA[8] has VCC driving its datain port
 Info: Pin DATA[9] has VCC driving its datain port
 Info: Pin DATA[10] has VCC driving its datain port
 Info: Pin DATA[11] has VCC driving its datain port
 Info: Pin DATA[12] has VCC driving its datain port
 Info: Pin DATA[13] has VCC driving its datain port
 Info: Pin DATA[14] has VCC driving its datain port
 Info: Pin DATA[15] has VCC driving its datain port

请各位大侠帮忙指点，谢谢