什么是 VHDL 中的多个恒定驱动程序错误 [英] What is multiple constant driver error in VHDL

问题描述

我正在为闪存接口开发 VHDL 程序.在编译我的程序时，我收到了这个错误.

I am developing a VHDL program for flash interface. While compiling my program I got this error.

(可点击)

正如您在图片中看到的，两个信号(右侧)经过xnor"处理，结果分配给输出 (flash_oe).

As you can see in the picture, two signals (right hand side) are "xnor" ed and result is assigned to output (flash_oe).

谁能描述一下这个错误信息是什么?

Can anyone describe what is this error message?

推荐答案

你在做这样的事情吗?

ENTITY test IS
  PORT ( sig1, sig3 : IN BIT;
         sig2 : OUT BIT);
END test;
---------------------------
ARCHITECTURE test_arch of test is
BEGIN
  PROCESS(sig1)
  BEGIN
    sig2 <= '0';
  END process;

  PROCESS(sig3)
  BEGIN
    sig2 <= '1';
  END process;
END test_arch;

让我们测试这段代码:

ghdl -a test.vhd
ghdl -e test
ghdl -r test

我们收到此错误:

sig2
./test:error: several sources for unresolved signal
for signal: .test(test_arch).ghdl: compilation error

这与您在上面发布的类似，这是因为我的代码在两个不同的进程中为 sig2 分配了一个值.如何将其实现到电路中?

This is similar to the one you have posted above and it's come up because my code assigns a value to sig2 in two different processes. How could this be implemented into a circuit?

也许有一个解决方法，我没有提供解决您的问题的方法，因为我不知道您的代码是什么样的.

Maybe there is a workaround, I have not provided a solution to your problem since I don't know how your code looks like.

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