Board DRC - Supposed to Generate Errors/Warnings on Unrouted Nets?

On 09/10/10 20:56, Michael Sansom wrote:

I just noticed that I have two unrouted nets on my board layout (i.e.

the ratsnets lines are visible but no copper tracks connect) and the DRC

isn't generating any errors/warning.  Is this correct?  What am I doing

wrong, I've never seen a DRC that wouldn't flag unrouted signals.

If the DRC were to warn about unrouted signals, it would ave to

run a complete RATSNEST (including processing all polygons) every

time the DRC is run. Clearly this is not desirable.

Klaus Schmidinger

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_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10

CadSoft Computer GmbH                   Fax:   +49-8635-6989-40

Pleidolfweg 15                          Email:   kls@cadsoft.de

D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de

_______________________________________________________________

On 9/13/2010 12:38 AM, Klaus Schmidinger wrote:

On 09/10/10 20:56, Michael Sansom wrote:

>> I just noticed that I have two unrouted nets on my board layout (i.e.

>> the ratsnets lines are visible but no copper tracks connect) and the DRC

>> isn't generating any errors/warning.  Is this correct?  What am I doing

>> wrong, I've never seen a DRC that wouldn't flag unrouted signals.

>

If the DRC were to warn about unrouted signals, it would ave to

run a complete RATSNEST (including processing all polygons) every

time the DRC is run. Clearly this is not desirable.

>

Klaus Schmidinger

I think it does not need to process the RATS, just warn that changes

were made and RATS has not been run yet, or that not all layers were

included in the DRC.

As discussed before, if there are DRC errors, it doesn't matter, it can

be skipped. It's just that misleading "No Errors" that is the problem.

Just one line of output.

And why does it need to run RATS anyway, don't you have a running tally

of unrouted nets in the status line? If this <>0 then you have unrouted

signals.

On 09/13/10 22:27, Gary Gofstein wrote:

...

And why does it need to run RATS anyway, don't you have a running tally

of unrouted nets in the status line? If this <>0 then you have unrouted

signals.

If the drawing has been modified since the last RATSNEST, airwires

might have become obsolete or new airwires might be necessary, due

to modifications to signal polygons.

Klaus Schmidinger

--

_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10

CadSoft Computer GmbH                   Fax:   +49-8635-6989-40

Pleidolfweg 15                          Email:   kls@cadsoft.de

D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de

_______________________________________________________________

On 9/14/2010 2:46 AM, Klaus Schmidinger wrote:

On 09/13/10 22:27, Gary Gofstein wrote:

>> ...

>> And why does it need to run RATS anyway, don't you have a running tally

>> of unrouted nets in the status line? If this<>0 then you have unrouted

>> signals.

>

If the drawing has been modified since the last RATSNEST, airwires

might have become obsolete or new airwires might be necessary, due

to modifications to signal polygons.

>

Klaus Schmidinger

If you run a DRC without doing a RATSNEST first, do you run the risk of

missing spacing violations because the polygons are old and haven't been

updated?

On 09/14/10 16:24, Michael Sansom wrote:

...

If you run a DRC without doing a RATSNEST first, do you run the risk of

missing spacing violations because the polygons are old and haven't been

updated?

No. The polygons are always calculated according to the same parameters

as used by the DRC. So it doesn't matter whether they are calculated or

not when the DRC is executed.

Klaus Schmidinger

--

_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10

CadSoft Computer GmbH                   Fax:   +49-8635-6989-40

Pleidolfweg 15                          Email:   kls@cadsoft.de

D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de

_______________________________________________________________

On 09/14/10 16:24, Michael Sansom wrote:

...

If you run a DRC without doing a RATSNEST first, do you run the risk of

missing spacing violations because the polygons are old and haven't been

updated?

No. The polygons are always calculated according to the same parameters

as used by the DRC. So it doesn't matter whether they are calculated or

not when the DRC is executed.

Klaus Schmidinger

--

_______________________________________________________________

Klaus Schmidinger                       Phone: +49-8635-6989-10

CadSoft Computer GmbH                   Fax:   +49-8635-6989-40

Pleidolfweg 15                          Email:   kls@cadsoft.de

D-84568 Pleiskirchen, Germany           URL:     www.cadsoft.de

_______________________________________________________________