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Hi, All,
I've written a hdl design, and simulate it now. But I can't find the
way to write a hdl testbench to test the design. I've googled, But I
can't find much material on net. could you give some advice or
recommand some online material on this field so that I can get a
general idea or deep knowledge on it? Thank you!

//Neil

Neil wrote:


> I've written a hdl design, and simulate it now. But I can't find the
> way to write a hdl testbench to test the design.

A testbench is nothing obscure. It is something you use to test your
design. It depends on you how a test should be designed.

Typically a testbench is a VHDL component that instantiates your design
inside plus some additional components you need (e.g. a clock generator).

Inside the testbench component you should generate some signals for your
design. You are free how to do this (components, functions, procedures,
synthesizable or not...). You may use the complete set of VHDL.


> I've googled, But I
> can't find much material on net.

This is because a testbench is always specialized for one design and
everybody writes testbenches a little bit different.



Ralf

Neil wrote:

> I've written a hdl design, and simulate it now. But I can't find the
> way to write a hdl testbench to test the design.

Step one is to install a vhdl simulator
and run some tutorial examples.

A testbench is a text file.
It includes a null entity and
architecture processes
to wiggle and watch the design instance.

Besides the UUT instance, I normally
use a clock/reset generation process
and a main process to wiggle and watch.

Here's an example
http://tinyurl.com/cv43m

-- Mike Treseler

Hi, Mike,
Thank you first.
I use Modelsim as my simulator, and now use waveform to simulate. but
it seems not a good way when the design needs a long simulating time
and the input signals are changed both regular and irregular.

Let me read the sample first to get a general idea. thank you again.

//Neil

Hi Neil,

> I use Modelsim as my simulator, and now use waveform to simulate. but
> it seems not a good way when the design needs a long simulating time
> and the input signals are changed both regular and irregular.
>
> Let me read the sample first to get a general idea. thank you again.

The attached three files might also be of interest. They follow roughly the
same pattern but give you something to chew on. I wrote these on a Linux
box, so you may not be able to open them properly with Notepad, but most
other editors won't have any trouble with them.

I find the use of the txt_util package most useful because you don't need to
rely on ASSERT all the time.

Best regards,


Ben

Neil wrote:
> Hi, All,
> I've written a hdl design, and simulate it now. But I can't find the
> way to write a hdl testbench to test the design. I've googled, But I
> can't find much material on net. could you give some advice or
> recommand some online material on this field so that I can get a
> general idea or deep knowledge on it? Thank you!

Start here:

http://janick.bergeron.com/wtb/

-a