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
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