Re: gEDA-user: Question about gschem DRC errors when using separate power pin symbols.

[John Doty <jpd@xxxxxxxxx>]

On Jun 11, 2009, at 10:53 AM, Andy Fierman wrote:

> Perhaps I should ask a different question then ....
>
> Is there a better tool to use for gschem DRC?

No, and it's really hard to do well, because gEDA is so flexible.  
What constitutes a DRC error depends on the details of *your* design  
flow, circuit details, and requirements.

>
> In the meanwhile, I think I may add a comment to the pwr pins symbol
> to remind me that it will show up a refdes and slot error.
>

Always assume that the *majority* of drc2 complaints are bogus. Check  
the netlist (as you did). Then you'll be able to use it. It's useful  
if you understand that it is usually wrong, because occasionally it's  
right and finds a problem that would be hard to find otherwise.

> :)
>
> I think that answers my question
>
> Thanks,
>
>          Andy.
>
> http://signality.co.uk
>
>
>
> 2009/6/11 John Doty <jpd@xxxxxxxxx>:
>> drc2 has a very narrow view of how the world works. If you are doing
>> a pure digital design using a single logic family using hidden power
>> pins, it's not *too* bad. But generally, it hides real errors behind
>> a flood of messages about things that aren't errors at all. gEDA is
>> much more flexible than drc2 understands. It's generally only useful
>> if you've learned to find the few real issues in the flood.
>>
>> DEVELOPERS:
>>
>> WHY DO WE RECOMMEND THIS FLAWED, NARROW, EXPERT TOOL, REPEATEDLY AND
>> OBNOXIOUSLY, TO ALL WHO USE GNETLIST, EVERY TIME THEY USE IT?
>>
>> On Jun 11, 2009, at 10:28 AM, Andy Fierman wrote:
>>
>>> Hi,
>>>
>>> I'm puzzled by a couple of gschem DRC errors I'm getting.
>>>
>>> I'm using Stefan Salewski's quad comparator symbol with the separate
>>> power pins symbol. I have four comparators plus the power pin symbol
>>> all with the refdes of U1. All symbols are given an SO14.fp  
>>> footprint.
>>>
>>> When I run:
>>>
>>>    gnetlist -g drc2 hv-psu_090608.sch -o drc_output.txt
>>>
>>> I get errors.
>>>
>>> Here's the message:
>>>
>>> ---------------
>>> gEDA/gnetlist version 1.4.0.20080127
>>> gEDA/gnetlist comes with ABSOLUTELY NO WARRANTY; see COPYING for
>>> more details.
>>> This is free software, and you are welcome to redistribute it under
>>> certain
>>> conditions; please see the COPYING file for more details.
>>>
>>> Remember to check that your schematic has no errors using the drc2
>>> backend.
>>> You can do it running 'gnetlist -g drc2 your_schematic.sch -o
>>> drc_output.txt'
>>> and seeing the contents of the file drc_output.txt.
>>>
>>> Loading schematic [/home/andyfierman/gaf/projects/hv-psu/RC1/hv-
>>> psu_090608.sch]
>>> DRC errors found. See output file.
>>> ---------------
>>>
>>> and when I check the output file (drc_output.txt), I can see that  
>>> the
>>> errors are due to the duplicate reference to U1.
>>>
>>> ---------------
>>> Checking non-numbered parts...
>>>
>>> Checking duplicated references...
>>> ERROR: Duplicated reference U1.
>>>
>>> Checking nets with only one connection...
>>>
>>> Checking pins without the 'pintype' attribute...
>>>
>>> Checking type of pins connected to a net...
>>>
>>> Checking unconnected pins...
>>>
>>> Checking slots...
>>>
>>> Checking duplicated slots...
>>> ERROR: duplicated slot 1 of uref U1
>>>
>>> Checking unused slots...
>>>
>>> No warnings found.
>>> Found 2 errors.
>>> ---------------
>>>
>>> Running this schematic through gsch2pcb works OK: I get no  
>>> problems in
>>> PCB and all the pins on U1 are connected correctly.
>>>
>>>
>>> Reading the FAQ at:
>>>
>>> http://geda.seul.org/wiki/geda:faq-
>>> gschem#what_should_i_do_about_power_pins_on_my_symbolsmake_them_visi 
>>> bl
>>> e_explicit_or_invisible_implicit
>>>
>>> tells me:
>>>
>>> ---------------
>>> .... That said, it may still be useful to detach the power pins from
>>> the functional part of the symbol. To do so, define a seperate power
>>> symbol and give it the same refdes as the functional part. A run of
>>> gsch2pcb will treat the siblings properly as one single  
>>> component. As
>>> neither gschem nor gsch2pcb explicitely know that the component is
>>> only complete with both symbols defined, you have to check yourself.
>>> With this workaround, you can draw all power related circuitry in  
>>> one
>>> corner of the schematic where it does not interfere with the signal
>>> nets. In many cases this is advantageous with analog circuits.
>>> ---------------
>>>
>>>
>>> ** Therefore, my question is this: are the gschem DRC errors for  
>>> such
>>> symbols to be expected?
>>>
>>> Any insight on this would be gratefully received.
>>>
>>> Thanks,
>>>
>>>    Andy
>>>
>>> http://signality.co.uk
>>>
>>>
>>> _______________________________________________
>>> geda-user mailing list
>>> geda-user@xxxxxxxxxxxxxx
>>> http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
>>>
>>
>> John Doty              Noqsi Aerospace, Ltd.
>> http://www.noqsi.com/
>> jpd@xxxxxxxxx
>>
>>
>>
>>
>> _______________________________________________
>> geda-user mailing list
>> geda-user@xxxxxxxxxxxxxx
>> http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
>>
>
>
> _______________________________________________
> geda-user mailing list
> geda-user@xxxxxxxxxxxxxx
> http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
>

John Doty              Noqsi Aerospace, Ltd.
http://www.noqsi.com/
jpd@xxxxxxxxx




_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user