Poll: Should we increase the number of signal layers?

First, Im glad you asked Here is my $0.02 pocket change.

"Klaus Schmidinger" <Klaus.Schmidinger@cadsoft.de> wrote in message

news:i65392$7e6$1@cheetah.cadsoft.de...

Here's how this could be done:

>

- The number of signal layers is increased to 32.

- The Top layer remains at '1', the Bottom layer becomes '32'.

- When updating files from an older version, all board layers

above '8' are shifted upwards by 16.

Have you considered "sub layers"? That would disconnect the meaning of a

layer being a physical copper layer, but rather could be a sandwich of

several layers.

What about NOT defining the last one as bottom layer, but rather the lowest

one in use by the DRC stack setting? Is there a good reason to fix the

bottom layer number?

Personally I think its time to get rid of layer numbers in general. For old

projects imported into newer version you can use the layer numbers as their

names. Backside is that ULP/SCR interpreter may have to have a "legacy

mode"..?

There are a few possible problems with this:

- ULPs that use concrete layer numbers instead of the constants

defined in "Help/User Language/Object Types/UL_LAYER" might

not work any more. This can be fixed by using the defined constants.

- Scripts that use concrete layer numbers instead of layer names

might not work any more. There is no easy fix for this, because

the layer names may be different from user to user (that's why

scripts used the layer numbers in the first place). The only

way to really fix this is to edit the scripts accordingly.

If bottom layer number is dynamic, and stack was configured right, old stuff

would work, at least on old projects.

Maybe you could get a warning/error if you try to run old ulp/scr that

doesnt  "unlock" new functionality with correct "#requre".

- Design Rules and Autorouter parameters that are stored in a board

file will be adjusted automatically.

- Externally stored Design Rules and Autorouter control files

will need to be modified accordingly.

- CAM job files will need to be modified accordingly.

Klaus Schmidinger schrieb:

We are currently designing the new data structure of EAGLE,

and this seems to be the right time to consider increasing the

maximum number of signal layers (which has been requested

repeatedly in the past).

Like Silviu, I personally never saw a need for that. However, if you

want to address people who do, it's no problem for me if EAGLE supports

even more layers that I don't use...

Here's how this could be done:

 

- The number of signal layers is increased to 32.

- The Top layer remains at '1', the Bottom layer becomes '32'.

- When updating files from an older version, all board layers

  above '8' are shifted upwards by 16.

I like the idea of Morten: access the layers /only/ by name in future.

If ULPs or scripts make use of layer numbers, map them to the correct

names. This is (and will always be!) upward compatible. The new layers

will be accessible by name only.

You'll probably need to add layer aliases, though - currently, layers

can be given custom names; this could be replaced by alias names.

If custom defined layers (>100) were used and later referenced

numerically by ULP or script, a warning would eventually appear if

there's no easy way to maintain backward compatibility (perhaps there is

- I didn't think too deep about this).

Using layer names only is an idea worth thinking about, IMHO.

(How EAGLE deals with them internally, and probably maps them to

internal layer IDs, is up to you. )

While we're at layers: I would like much more layers in the schematic

editor, to separate pin names, pad numbers etc.. Perhaps it's possible

to have a look at these, too, when talking about new data structures.

Thanks,

Tilmann

Am 07.09.2010 12:13, schrieb Klaus Schmidinger:

What is the EAGLE users' opinion about this?

Should we do it?

In our Institute

  - we never use more than 6 layers and

  - we don't use autorouter, scripts or CAM processor.

  - Problems COULD occur with design rules and ULPs, but these

    can be fixed more or less quickly.

Therefore: I myself would opt quite weakly for "don't do it", because it

COULD mean some hours of additional work for me, but I wouldn't say "no"

if other people really need that sort of stuff...

Andreas Weidner

Am 07.09.2010 12:13, schrieb Klaus Schmidinger:

We are currently designing the new data structure of EAGLE,

and this seems to be the right time to consider increasing the

maximum number of signal layers (which has been requested

repeatedly in the past).

>

Here's how this could be done:

>

- The number of signal layers is increased to 32.

- The Top layer remains at '1', the Bottom layer becomes '32'.

- When updating files from an older version, all board layers

   above '8' are shifted upwards by 16.

>

There are a few possible problems with this:

>

- ULPs that use concrete layer numbers instead of the constants

   defined in "Help/User Language/Object Types/UL_LAYER" might

   not work any more. This can be fixed by using the defined constants.

- Scripts that use concrete layer numbers instead of layer names

   might not work any more. There is no easy fix for this, because

   the layer names may be different from user to user (that's why

   scripts used the layer numbers in the first place). The only

   way to really fix this is to edit the scripts accordingly.

- Design Rules and Autorouter parameters that are stored in a board

   file will be adjusted automatically.

- Externally stored Design Rules and Autorouter control files

   will need to be modified accordingly.

- CAM job files will need to be modified accordingly.

>

What is the EAGLE users' opinion about this?

Should we do it?

Are there more possible problems than the above ones?

>

Again, if we are going to make this change, it will need to

happen now, as we switch to an all new data structure.

>

Klaus Schmidinger

My uppermost were 8 layers and with nowerdays a half-dozen supply layers

it would still be enough for me

I say no to nothing, do the best you can do, some users will still whine.

I like the idea of Mortons layer-names only, and Tillmans Idea of more

layers in .sch .

One wish I have for layers is the possibility to erase internal eagle

layers even if they are not empty, with a warning perhaps, but possible.

(You should see the rubbish I sometimes get...).

Anyway I wish you a lucky hand for the new design.

--

Gruß / regards

Joern

We are currently designing the new data structure of EAGLE,

and this seems to be the right time to consider increasing the

maximum number of signal layers (which has been requested

repeatedly in the past).

>

Here's how this could be done:

>

- The number of signal layers is increased to 32.

- The Top layer remains at '1', the Bottom layer becomes '32'.

- When updating files from an older version, all board layers

above '8' are shifted upwards by 16.

>

That would work for me I suppose and I don't care if ULP's have to be

reworked. However, I've never had need for more than 8 layers at this point

with around 300-500 pin BGA devices being the max. Other issues become a

problem when boards get this big and eagle gets scary slow drawing larger

multi-layer boards with multiple flooded power planes and lots of traces.

The above said, if you need to make a 32 layer mother board then you need

another cad package IMHO. You'll need things like auto push/shove, diff pair

routing, intelligent shaped based auto-router, auto-fanout, etc, etc. If you

plan on adding these sorts of features later (and competing with Altium,

Mentor and Orcad) then yes, add the extra layers or reserve space in the new

data structures.

Bob

Andrew Sterian schrieb:

>> I would say be bold, be brave and be decisive.

>> Nothing criples a new product more than hanging on to legacy support.

 

I would agree most with this reply.

However, if compatibility can be achieved without additional effort and

without any disadvantages for the new version, it's better to support

the old files as well.

I'd also state that of all the feature requests thrown around, this one

is pretty low priority. Really, how many people use Eagle for 16-layer

designs?

 

Do it if you can, Re: Poll: Should we increase the number of signal layers?, but please do more important things first

Fully agreed.

Tilmann

Klaus Schmidinger wrote on Tue, 07 September 2010 06:13

We are currently designing the new data structure of EAGLE,

and this seems to be the right time to consider increasing the

maximum number of signal layers (which has been requested

repeatedly in the past).

I've never used more than 6 layers, and that only once.  Mostly I use 2 and

sometimes 4 layers.

Quote:

- The number of signal layers is increased to 32.

Increase it if you really see a need, but why must the number of layers be

fixed?  Shouldn't this come from the DRC?  I can see making 32 the maximum

possible number of layers, but it would be nice if my DRC is set to only 4

layers that Eagle acts as if there are only layers 1-4 with 1 being top and

4 being bottom.  Does the special bottom layer really need to be hard

coded?  It's already annoying enough now that when routing a 2 layer board

and you hit the middle mouse button that all the unused layers show up even

when the DRC only specifies two layers.

Quote:

- When updating files from an older version, all board layers above '8'

are shifted upwards by 16.

That might break some scripts and ULPs that assume layer 16 is the bottom,

although they should have been using "bottom" instead of 16.

Quote:

- ULPs that use concrete layer numbers instead of the constants

  defined in "Help/User Language/Object Types/UL_LAYER" might

  not work any more.

How about give us a constant the indicates the last layer number.  Actually

if the valid layers come from the DRC (I think they should) then this could

be different per design.  Put another way, this value accessible via ULP

would provide the layer number of the bottom layer, which would now depend

on the design.  That means looping over all layers in use would be as easy

as looping from 1 to the bottom layer value.

Quote:

What is the EAGLE users' opinion about this?  Should we do it?

 

Again, if we are going to make this change, it will need to

happen now, as we switch to an all new data structure.

If some people need more than 16 layers, you should do it.  Eagle should be

capable of making any real board, although there are other features that I

think are higher priority, especially if you want to support designs so

complex that they require more than 16 layers.

--

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