gtkwave not displaying ghdl simulation.

[Neil Dugan]

Hi,
I am new to VHDL and tried this example I found. The 'report'
statements show that the simulation appears to work. But gtkwave isn't
showing any output. Why?

I am using
GHDL 0.21 (20051218) [Sokcho edition]
GTKWave Analyzer v1.3.81

These came with my Ubuntu 6.10 distribution


Regards Neil.

 

[Paul Uiterlinden]

Neil Dugan wrote:

Hi,
I am new to VHDL and tried this example I found. The 'report'
statements show that the simulation appears to work. But gtkwave isn't
showing any output. Why?

Is a VCD file generated at all, and does it contain any data? It should be
readable (but not comprehensible) with any text editor.

I'm afraid I can not help you any further, as my installation of ghdl does
not work anymore. I think it is because I now use a 64 bit OS.
"ghdl -a adder.vhdl" throws a bunch of error messages at me:

adder.s: Assembler messages:
adder.s:128: Error: suffix or operands invalid for `push'
adder.s:135: Error: suffix or operands invalid for `push'

I have some side remarks though:

You can remove the library and use clauses from adder.vhdl and
tb_adder.vhdl. You only use type "bit", so package std_logic_1164 is not
needed.

In your makefile you load tb_adder for simulation. You also have a
configuration, but you don't use it. It would be better to load
cfg_tb_adder instead. In this particular case it does not matter as there
is only one architecture. By making it a habit to always use a toplevel
configuration, you may avoid some possible mixups in the future.

Hopefully you'll find what's wrong with the VCD output.

--
Paul Uiterlinden
www.aimvalley.nl
e-mail addres: remove the not.

 

Paul Uiterlinden wrote:

Neil Dugan wrote:

Hi,
I am new to VHDL and tried this example I found. The 'report'
statements show that the simulation appears to work. But gtkwave isn't
showing any output. Why?

There's no output shown because you conceivably could be looking at a
VCD file that has hundreds of thousands of nets in it. So you have to
import nets manually.

Is a VCD file generated at all, and does it contain any data? It should be
readable (but not comprehensible) with any text editor.

If you're on a pre GTK-2.8 box you have to bring up the tree window
separately.

Search->SignalSearchTree
Then add signals from there.

-Tony

 

[Neil Dugan]

bybell@rocketmail.com wrote:

Paul Uiterlinden wrote:

Neil Dugan wrote:


Hi,
I am new to VHDL and tried this example I found. The 'report'
statements show that the simulation appears to work. But gtkwave isn't
showing any output. Why?


There's no output shown because you conceivably could be looking at a
VCD file that has hundreds of thousands of nets in it. So you have to
import nets manually.


Is a VCD file generated at all, and does it contain any data? It should be
readable (but not comprehensible) with any text editor.


If you're on a pre GTK-2.8 box you have to bring up the tree window
separately.

Search->SignalSearchTree
Then add signals from there.

Yes that was it, thanks.

-Tony

Regards Neil.