Mail Archives: geda-help/2016/03/11/16:45:49
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I do the following:
1. Create the schematic without the AGnd and DGnd nets connected. =
Route the board. When finished, DRC it.
2. Change the schematic to connect the nets together. Usually I have a =
separate section of the schematic that makes this explicit. Change the =
PCB to reflect this change.
3. DRC the layout to verify that there are no new errors.
Step 1 ensures that the layout is complete and that there are no =
inadvertent connections between AGnd and DGnd. Step 2 adds the =
connection, and step 3 ensures that the addition is correct and no =
inadvertent connections were made or lost. For simplicity, do steps 2 =
and 3 only after the board is otherwise complete. If you choose to edit =
the design at a later date, remove the AGnd - DGnd connection on both =
schematic and board, DRC to ensure correctness, edit the schematic, edit =
the PCB to match, DRC the edited PCB, then do steps 2 and 3 above again.
A little tedious, but it works fine for me. One caution: Put a note in =
the schematic and in the area outside the cutting marks on the PCB to =
explain where the connection is located on the PCB. That makes it much =
easier to remove it during future edits. Otherwise, you _will_ forget =
where it is and that makes finding supposed DRC error a real pain!
Best regards,
Peter
Peter Gregson, Ph.D., F.E.C., P.Eng.
Engineer in Residence
Professor, E&CE
=93A good engineer is someone who can do for 50 cents what any idiot can =
do for a dollar!=94 =97S. Campbell
> On Mar 11, 2016, at 3:50 PM, James Battat (jbattat AT wellesley DOT edu) [via =
geda-help AT delorie DOT com] <geda-help AT delorie DOT com> wrote:
>=20
> I=92m also hesitant to use the =93do this at the last minute=94 =
scheme.
>=20
> A through hole jumper is certainly an option, but I was hoping for a =
solution that didn=92t require a physical component (e.g. a =93virtual=94 =
component in gschem + pcb that allows you to legally connect the AGND =
and DGND nets.
>=20
> Open to suggestions from other folks as well (I imagine this is a very =
common need =97 single-point ground in a mixed signal board).
>=20
> Thanks,
> James
>=20
> On Mar 11, 2016, at 2:34 PM, Mike Bushroe (mbushroe AT gmail DOT com =
<mailto:mbushroe AT gmail DOT com>) [via geda-help AT delorie DOT com =
<mailto:geda-help AT delorie DOT com>] <geda-help AT delorie DOT com =
<mailto:geda-help AT delorie DOT com>> wrote:
>=20
>> What about using a through hole jumper to perform the same function =
as the zero ohm SMD when the planes are on the surface? Assuming you =
have some freedom to place the cross connect anywhere along their =
boarder you should be able to find two spots for the through holes. I =
don't know if that would change the cost of manufacturing an otherwise =
all SMD board with only layer to layer vias, but I would think the =
process for making a top to bottom via would also make plated through =
holes.
>>=20
>> I just know that setting up something I just HAVE to do on the very =
last run before submitting is a surefire recipe for disaster for me. I =
would rather put up with seeing the short every time I rand DRC than =
risk sending the files off to hastily.
>>=20
>>=20
>> Mike
>>=20
>> On Fri, Mar 11, 2016 at 12:20 PM, Peter Clifton =
(petercjclifton AT googlemail DOT com <mailto:petercjclifton AT googlemail DOT com>) =
[via geda-help AT delorie DOT com <mailto:geda-help AT delorie DOT com>] =
<geda-help AT delorie DOT com <mailto:geda-help AT delorie DOT com>> wrote:
>> (And be CAREFUL)... I've missed nets because of this. Be sure to make =
the short at the last possible moment.
>>=20
>> Peter
>>=20
>> On 10 March 2016 at 22:16, DJ Delorie <dj AT delorie DOT com =
<mailto:dj AT delorie DOT com>> wrote:
>>=20
>> There's no change since forever for this, it's been the same all =
along
>> - you have to manually short the two grounds as the last step in
>> layout, and ignore the DRC errors for those grounds after that.
>>=20
>>=20
>>=20
>>=20
>> --=20
>> "Creativity is intelligence having fun." =97 Albert Einstein
>=20
--Apple-Mail=_AD149F33-C66F-4870-879F-6D74A6FF6C60
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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dwindows-1252"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D"">I do the following:<div class=3D""><br class=3D""></div><div =
class=3D"">1. Create the schematic without the AGnd and DGnd nets =
connected. Route the board. When finished, DRC it.</div><div =
class=3D"">2. Change the schematic to connect the nets together. =
Usually I have a separate section of the schematic that makes this =
explicit. Change the PCB to reflect this change.</div><div class=3D"">3. =
DRC the layout to verify that there are no new errors.</div><div =
class=3D""><br class=3D""></div><div class=3D"">Step 1 ensures that the =
layout is complete and that there are no inadvertent connections between =
AGnd and DGnd. Step 2 adds the connection, and step 3 ensures that =
the addition is correct and no inadvertent connections were made or =
lost. For simplicity, do steps 2 and 3 only after the board is =
otherwise complete. If you choose to edit the design at a later =
date, remove the AGnd - DGnd connection on both schematic and board, DRC =
to ensure correctness, edit the schematic, edit the PCB to match, DRC =
the edited PCB, then do steps 2 and 3 above again.</div><div =
class=3D""><br class=3D""></div><div class=3D"">A little tedious, but it =
works fine for me. One caution: Put a note in the schematic =
and in the area outside the cutting marks on the PCB to explain where =
the connection is located on the PCB. That makes it much easier to =
remove it during future edits. Otherwise, you _will_ forget where =
it is and that makes finding supposed DRC error a real pain!</div><div =
class=3D""><br class=3D""></div><div class=3D"">Best regards,</div><div =
class=3D""><br class=3D""></div><div class=3D"">Peter</div><div =
class=3D""><br class=3D""></div><div class=3D"">Peter Gregson, Ph.D., =
F.E.C., P.Eng.<br class=3D"">Engineer in Residence<br =
class=3D"">Professor, E&CE<br class=3D""><br class=3D""></div><div =
class=3D""><br class=3D""></div><div class=3D"">=93A good engineer is =
someone who can do for 50 cents what any idiot can do for a dollar!=94 =
=97S. Campbell</div><div class=3D""><br class=3D""></div><div =
class=3D""><div apple-content-edited=3D"true" class=3D"">
<div style=3D"color: rgb(0, 0, 0); letter-spacing: normal; orphans: =
auto; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><br class=3D""></div>
</div>
<br class=3D""><div apple-content-edited=3D"true" class=3D""><br =
class=3D""><br class=3D""><br class=3D"">
</div>
<br class=3D""><div><blockquote type=3D"cite" class=3D""><div =
class=3D"">On Mar 11, 2016, at 3:50 PM, James Battat (<a =
href=3D"mailto:jbattat AT wellesley DOT edu" =
class=3D"">jbattat AT wellesley DOT edu</a>) [via <a =
href=3D"mailto:geda-help AT delorie DOT com" =
class=3D"">geda-help AT delorie DOT com</a>] <<a =
href=3D"mailto:geda-help AT delorie DOT com" =
class=3D"">geda-help AT delorie DOT com</a>> wrote:</div><br =
class=3D"Apple-interchange-newline"><div class=3D""><meta =
http-equiv=3D"Content-Type" content=3D"text/html charset=3Dwindows-1252" =
class=3D""><div style=3D"word-wrap: break-word; -webkit-nbsp-mode: =
space; -webkit-line-break: after-white-space;" class=3D"">I=92m also =
hesitant to use the =93do this at the last minute=94 scheme.<div =
class=3D""><br class=3D""></div><div class=3D"">A through hole jumper is =
certainly an option, but I was hoping for a solution that didn=92t =
require a physical component (e.g. a =93virtual=94 component in gschem + =
pcb that allows you to legally connect the AGND and DGND nets.<br =
class=3D""><div class=3D""><br class=3D""><div =
apple-content-edited=3D"true" class=3D"">
<div style=3D"letter-spacing: normal; orphans: auto; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; widows: =
auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: =
break-word; -webkit-nbsp-mode: space; -webkit-line-break: =
after-white-space;" class=3D"">Open to suggestions from other folks as =
well (I imagine this is a very common need =97 single-point ground in a =
mixed signal board).</div><div style=3D"letter-spacing: normal; orphans: =
auto; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><br class=3D""></div><div style=3D"letter-spacing: normal; =
orphans: auto; text-align: start; text-indent: 0px; text-transform: =
none; white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D"">Thanks,</div><div style=3D"letter-spacing: normal; orphans: =
auto; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D"">James</div><div style=3D"letter-spacing: normal; orphans: =
auto; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><br class=3D""></div></div><div class=3D""><div class=3D"">On =
Mar 11, 2016, at 2:34 PM, Mike Bushroe (<a =
href=3D"mailto:mbushroe AT gmail DOT com" class=3D"">mbushroe AT gmail DOT com</a>) =
[via <a href=3D"mailto:geda-help AT delorie DOT com" =
class=3D"">geda-help AT delorie DOT com</a>] <<a =
href=3D"mailto:geda-help AT delorie DOT com" =
class=3D"">geda-help AT delorie DOT com</a>> wrote:</div><br =
class=3D"Apple-interchange-newline"><blockquote type=3D"cite" =
class=3D""><div dir=3D"ltr" class=3D"">What about using a through hole =
jumper to perform the same function as the zero ohm SMD when the planes =
are on the surface? Assuming you have some freedom to place the cross =
connect anywhere along their boarder you should be able to find two =
spots for the through holes. I don't know if that would change the cost =
of manufacturing an otherwise all SMD board with only layer to layer =
vias, but I would think the process for making a top to bottom via would =
also make plated through holes.<div class=3D""><br class=3D""></div><div =
class=3D""> I just know that setting up something I just HAVE to =
do on the very last run before submitting is a surefire recipe for =
disaster for me. I would rather put up with seeing the short every time =
I rand DRC than risk sending the files off to hastily.</div><div =
class=3D""><br class=3D""></div><div class=3D""><br class=3D""></div><div =
class=3D"">Mike</div></div><div class=3D"gmail_extra"><br class=3D""><div =
class=3D"gmail_quote">On Fri, Mar 11, 2016 at 12:20 PM, Peter Clifton =
(<a href=3D"mailto:petercjclifton AT googlemail DOT com" =
class=3D"">petercjclifton AT googlemail DOT com</a>) [via <a =
href=3D"mailto:geda-help AT delorie DOT com" =
class=3D"">geda-help AT delorie DOT com</a>] <span dir=3D"ltr" class=3D""><<a =
href=3D"mailto:geda-help AT delorie DOT com" target=3D"_blank" =
class=3D"">geda-help AT delorie DOT com</a>></span> wrote:<br =
class=3D""><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 =
.8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr" =
class=3D""><div class=3D"">(And be CAREFUL)... I've missed nets because =
of this. Be sure to make the short at the last possible moment.<br =
class=3D""><br class=3D""></div>Peter<br class=3D""></div><div =
class=3D"gmail_extra"><br class=3D""><div class=3D"gmail_quote">On 10 =
March 2016 at 22:16, DJ Delorie <span dir=3D"ltr" class=3D""><<a =
href=3D"mailto:dj AT delorie DOT com" target=3D"_blank" =
class=3D"">dj AT delorie DOT com</a>></span> wrote:<br class=3D""><blockquote =
class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc =
solid;padding-left:1ex"><br class=3D"">
There's no change since forever for this, it's been the same all =
along<br class=3D"">
- you have to manually short the two grounds as the last step in<br =
class=3D"">
layout, and ignore the DRC errors for those grounds after that.<br =
class=3D"">
</blockquote></div><br class=3D""></div>
</blockquote></div><br class=3D""><br clear=3D"all" class=3D""><div =
class=3D""><br class=3D""></div>-- <br class=3D""><div =
class=3D"gmail_signature"><div dir=3D"ltr" class=3D""><span =
style=3D"font-family:arial,sans-serif;font-size:11pt" =
class=3D"">"Creativity is intelligence having fun." =97 Albert =
Einstein</span></div></div>
</div>
</blockquote></div><br =
class=3D""></div></div></div></div></blockquote></div><br =
class=3D""></div></body></html>=
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