Hi Cedric,

Does the issue go away if you comment out test.start_tb(...) and all
instances of test.start_test(...) and test.end_test() in the testbench?

Jonathon

On Thu, Jan 7, 2021, 12:49 Cédric Hannotier via USRP-users <
usrp-users@lists.ettus.com> wrote:

On 11/01/21 21:40, Jonathon Pendlum wrote:

Hi Jonathon,

If I comment out test.{start,end}_tb, it fails with:
"Fatal: The connected block has an incompatible backend interface".
The testbench is unusable in this case (whatever the GUI value).

If I comment out test.{start,end}_test, it prints:
"Fatal: No test running",
but proceed to run the full testbench (without reporting test status).
With GUI=1, I get the same error message than previously:
"FATAL_ERROR: Vivado Simulator kernel has discovered
an exceptional condition from which it cannot recover"

Regards

Cédric Hannotier

Hi Cedric,

"Fatal: The connected block has an incompatible backend interface".

Try adding a short delay, such as #1 or @posedge( at the start of the
testbench to get past this.

Jonathon

On Tue, Jan 12, 2021 at 1:04 AM Cédric Hannotier cedric.hannotier@ulb.be
wrote:

On 12/01/21 13:42, Jonathon Pendlum via USRP-users wrote:

Hi Jonathon,

Thanks for the workaround, it works!
However, it has some side effects.

Doing

//test.start_tb
#1
...
//test.end_tb

or

test.start_tb
...
//test.end_tb

give the same result.
Indeed, the issue is with test.end_tb finishing the simulation.
It is fine in cli, but not in GUI, since Vivado is generating waves.

Commenting out test.end_tb solves the issue with GUI mode,
but then the simulation does not stop in cli mode after
all tests are completed (it only stops after 10ms).
Furthermore, I loose the summary at the end (time elapsed,
#passed/failed tests, etc.)

Is there a way to reconcile both modes (cli & GUI) without editing
my testbench every time I need to switch between these two modes?

Regards

Cédric Hannotier

Hi Cédric,

You can probably just call $finish() instead of test.end_tb() to stop the
simulation in both CLI and GUI modes. If you want the summary at the end,
take a look at what end_tb() does in PkgTestExec.sv. Also, note that the
test object isn't required. You can remove all the test calls from your
code and just use SystemVerilog assertions instead if you prefer.

Wade

On Wed, Jan 13, 2021 at 4:58 AM Cédric Hannotier via USRP-users <
usrp-users@lists.ettus.com> wrote:

Hi Wade,

On 13/01/21 10:00, Wade Fife wrote:

Indeed!
After reading PkgTestExec.sv, I found something that reconcile both:

test.start_tb()
...
test.end_tb(0) // will not call $finish()
$finish()

Thanks!

Cédric Hannotier