simulation and test bench

Hello,

Can somebody advice me that whats the difference between the simulation
and test bench. I am using Quatrus these days and it has a simulator. I
wrote a VHDL program and took it into the simulator, define clock and
other control signals and started testing my design. Now, somebody told
me that I need to write a test bench too. I do not know why. Please
adivce. Thanks
Regards
john

john

john wrote:

> Can somebody advice me that whats the difference between the simulation
> and test bench. I am using Quatrus these days and it has a simulator. I
> wrote a VHDL program and took it into the simulator, define clock and
> other control signals and started testing my design.

The Quartus simulator tests a synthesis netlist, not source code.
Using an HDL simulator like modelsim, I can apply stimulus
algorithmically using a testbench like this:

http://home.comcast.net/~mike_treseler/test_uart.vhd

and it will draw the waveforms for me, like this

http://home.comcast.net/~mike_treseler/uart_sim.pdf

> Now, somebody told
> me that I need to write a test bench too. I do not know why.

The Quartus simulator is adequate for small designs.
If you haven't run into its limitations,
there is no need to change horses yet.


-- Mike Treseler

Mike Treseler

john wrote:


> Now, somebody told
> me that I need to write a test bench too. I do not know why.

A testbench is the environment you need to test your design. This means
at least test stimuli and it is recommended, that checks, if the device
under test operated well, are also included (automatic verification).

Do something, that proves, that (hopefully) no bugs are int the
component. Every function, that is not tested can be seen as "not working".

Ralf

Ralf Hildebrandt

john wrote:
> Can somebody advice me that whats the difference between the simulation
> and test bench. I am using Quatrus these days and it has a simulator. I
> wrote a VHDL program and took it into the simulator, define clock and
> other control signals and started testing my design. Now, somebody told
> me that I need to write a test bench too. I do not know why. Please
> adivce. Thanks

See http://janick.bergeron.com/wtb/wtb2/

-a

Andy Peters