Unexpected behavior of EAGLE layout editor

On 22/07/2017 3:35 a.m., SMD111 wrote:

The problem I have is described in the attached images (they are zoom-able).

I have a finalized, fully routed design:

 

  At some point I decided to add a new gate to the schematic, so I copy IC5 and paste it as IC9. Please note that no connections on IC9 have been made yet:

 

Simply placing this gate on schematic causes significant changes on the board. As you can see, multiple nets become ripped up, even the nets that have nothing to do with IC5 or IC9.

 

Is it possible to avoid this effect?

Thank you,

Sergey

 

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Hi Sergey

It's important to say which version of Eagle you are using.

I use v7.7 (Win7)  and can demonstrate I don't have  your problem.

Using the example Schem/Board Hexapod I can copy a device in the

schematic and it appears without air-wires on the board, ready to be

placed. The rest of the board remains unaltered.

It may be the technique you are using to copy the part (ah! maybe the v8

select mechanism has caught you out). I simply right click on the symbol

(IC5) and select copy from the context menu. Then you will only have the

IC stuck to the cursor and no nets connected to the pins.

HTH

Warren

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Hi Warren, thank you for replying.

I have EAGLE 6.4.0 Professional. It is old, but I like "good old" things :-)

And for copying, I just select the copy mode on the toolbar, then click on the gate, then the IC is duplicated and stuck to cursor, then I place it with a click. After that I press "Switch to board" button and see airwires in some places where traces used to be.

Hi Warren, thank you for replying.

I have EAGLE 6.4.0 Professional. It is old, but I like "good old" things :-)

And for copying, I just select the copy mode on the toolbar, then click on the gate, then the IC is duplicated and stuck to cursor, then I place it with a click. After that I press "Switch to board" button and see airwires in some places where traces used to be.

On 22/07/2017 8:14 a.m., SMD111 wrote:

Hi Warren, thank you for replying.

 

I have EAGLE 6.4.0 Professional. It is old, but I like "good old" things

 

I recommend downloading the last version 6 release which is 6.6 from here

ftp://ftp.cadsoft.de/eagle/program/

There were worthwhile fixes and added functionality in v6.5. and v6.6

I seem to remember 6.4 as being particularly not good.

Hopefully you still have your licence keys etc. If not you can get them

again from Autodesk support.

HTH

Warren

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On 22/07/2017 8:14 a.m., SMD111 wrote:

Hi Warren, thank you for replying.

 

I have EAGLE 6.4.0 Professional. It is old, but I like "good old" things

 

I recommend downloading the last version 6 release which is 6.6 from here

ftp://ftp.cadsoft.de/eagle/program/

There were worthwhile fixes and added functionality in v6.5. and v6.6

I seem to remember 6.4 as being particularly not good.

Hopefully you still have your licence keys etc. If not you can get them

again from Autodesk support.

HTH

Warren

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On 22/07/2017 8:14 a.m., SMD111 wrote:

Hi Warren, thank you for replying.

 

I have EAGLE 6.4.0 Professional. It is old, but I like "good old" things

 

And for copying, I just select the copy mode on the toolbar, then click on the gate, then the IC is duplicated and stuck to cursor, then I place it with a click. After that I press "Switch to board" button and see airwires in some places where traces used to be.

 

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The problem could be the following if the board is from a version prior

to v6.

The following is copied from the release notes (UPDATE_en.txt) which

comes with Eagle.

• Supply layers:

  - Supply layers (i.e. layers with names that start with a '$') are no

longer treated special. Layers for supply signals now need to be

realized using signal polygons.

  - When a board drawing from an older version of EAGLE is loaded, any

supply layers it contains will be renamed by moving the '$' to the end

of the name. This makes sure automated scripts that treat a supply layer

as "negative" don't make a mistake, while still indicating that layer as

having been a supply layer. The functionality of the supply layer is

replaced by a signal polygon with the proper name, using the minimum

wire width from the net class of that signal. The polygon is drawn into

the former supply layer as a rectangular shape, covering the area

defined by any wires in the Dimension layer, by pads or by vias. The

Autorouter setup is modified in such a way that the layer containing the

generated polygon is activated (with preferred direction '*'), and the

costs for that layer set to 99 in all passes.

VERY IMPORTANT:

After updating a board with supply layers from an older version, make

sure you run the RATSNEST command to verify whether all pads are still

connected to the respective signal.

HTH

Warren

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Hi Warren,

thanks again for your support and advise.

I was able to solve this problem, and would like to share with you how I did it.

This is a 4-layer board with the inner layers being VCC and GND. There are power supply traces ob both sides, too.

I usually keep the inner layers hidden (there is nothing to see there). So I accidentally discovered that having them hidden was the reason of EAGLE behavior as I described: all routed power traces get converted to airwires. However, if I make the power layers visible, then copy and place the new gate, all existing power traces stay preserved and only the new gate has airwires from its power pins to the nearest points corresponding to VCC and GND nets. This state does not change after I hide the inner layers again.

BTW, this is another oddity that power pins of a new gate get airwired to supply nets automatically, even though the supply pins on the schematic are not invoked yet.

Best,

Sergey