Hi!
I would like to talk about the biggest issue of KiCAD.
I. The problem
--------------
After some experience[1] with KiCAD I think the biggest bottleneck in
KiCAD is the file formats of the footprints and schematics.
In the following section I will refer to footprints and schematics as
library (in place of
library and modules as located right now).
a) Location of the library
---------------------------
* In linux, all the libraries is located in /usr/share, and the user
is unable
to modify the schematic and the footprint. (It needs to copied
somewhere
in the home directory).
b) Merging different libraries
------------------------------
* If I created a schematic, and saved into the appropriate library
(ex: device.lib), and
at work I create an another schematic. The merge of the two library is
really hard
(I need a text editor for this).
c) updates of the library
-------------------------
* Really hard to notice, if the default libraries (which comes with
kicad) has any new device inside.
d) using multiple locations(directories)
----------------------------------------
* To avoid unnecessary copies of the whole default library. It is
necessary to specify multiple
library location.
e) contribution back to the project
-----------------------------------
* It is really the same as the "merging different libraries" point. It
makes really hard to
contribute back to the project, because it is not a simple file,
which I could post back.
We need an unnecessary import/export which complicates life.
d) lack of versioning
------------------
* The title says it all. There are some case where would be nice to
notify, if a device was modified
and why. Currently in the default library there are many
unconsistancies, even If I correct
it. How someone would notice it? (ex: there is a footprint with
soic, while the other with s0ic.
So 0 vs o. hard to notice, but it is definitly an error. Other case:
upper case vs. lower case)
II. The solution
----------------
I was thinking many days now what would be the best for all the above
problems. I have also
read the mailing list for looking something similar. And I noticed,
that there is an ongoing
fileformat change effort. So I think the best time would be now to
discuss all of these
problems.
Informations about a device
------------------------
For a particular device, there are multiple information which needs to
be handle.
We need to handle: footprints, schematics, 3d representation,
documentation about the device
Let's take an example: tlp-281 optocoupler.
Which has a schematic (a led and a photosensitive transistor packaged
together),
has a footprints (smd, 4 legs, 1.27mm between two legs), and has a
phyisical package, which is now a soic4, which determines the 3d
representation.
The concrete model (tlp281) determine the datasheet and the
documentation,
which is unique between all the devices.
Orthogonality
-------------
a) schematic:
-------------
* The schematic implies footprints (for example a transistor implies
all the footprints which
has three legs. Or there are maybe device, which comes just some
packages).
b) footprint:
-------------
* A particular footprint implies a few physical package (3d
representation).
c) package:
-----------
* package<-> 3d model is a 1:1 relationship.
One schematic/footprint/package one file:
-----------------------------------------
This is the BIGGEST issue about the current design. Really.
There is no need to collect multiple schematic inside one file. There are
dedicated tools for that (an archiver: .zip, .tar.gz), if the size
matters.
There is a requirement about the new file format, that it needs to be
human readable and human (easily) understandable.
Have you managed to handle a file which has more then 2000 line of code?
So if the new fileformat needs to be human readable it needs also human
managable too.
Most important proposal:
------------------------
So I propose, that we split all the schematic bundles to invidual files.
Judging from the fileformat, it is *really* EASY.
It eliminates a bunch of problem. It makes really easy to contribute
back to the project.
Merging the documentation to appropriate file (future):
-------------------------------------------------------
Why handle separate the schematic and the documentation? (74xx.lib,
74xx.dcm)
I think the best would be that all the invidual schematics contains
also his documentation too.
Proposed directory structure:
-----------------------------
Here is the directory structure what I think would be the best:
/library/
This is the root of all information (not sourcecode)
/library/schematic/
It contains all the schematics splitting to the appropriate
subdirectories.
/library/schematic/audio/*.xxx
The current library/audio.lib file splitted to individual files.
/library/schematic/device/*.xxx
The current library/device.lib file splitted to individual files.
library/footprint/
It contains all the footprints separated to the appropriate folder.
library/footprint/display/*.xxx
The current modules/display.mod file splitted to individual files.
library/packages3D
Nothing needs to be done. The current structure is fine.
library/device
A new proposal here. It contains a file per physical device.
library/device/transistor/*.xxx
It contains all the transistors. A file then should contain information
about schematic, footprint, 3dpackage, and datasheet (url, or uri to a
pdf).
Changes in the project file (.pro)
--------------------------------
Currently, when a project is created, the libraries (what the project
are using)
is stored inside the schematic (.sch), and inside the board design(.brd).
It is necessary, that all the information about the libraries
(what the user are using) stored at one location. And I think the best
would
be inside the .pro file.
And while we are it, it would be nice also to use standard URI-s
instead of
C:\\Document and settings\\Username\\Desktop\\kicad\\library and
/home/username/Desktop/kicad/library
becomes something like:
file:///c/document and settings/username/desktop/kicad/library and
file:///home/username/desktop/kicad/library
And would be necessary also to be able specify multiple library,
something like:
<schematic>
file:///c/program files/kicad/library/schematic/
file:///c/document and settings/username/desktop/kicad/library/schematic
file:///home/username/desktop/kicad/library/schematic
</schematic>
So the user moves their project between different os, kicad would find
always the appropriate libraries. And search inside multiple location
(so system libraries and user libraries too)
Future file format
------------------
I dont think Im the right person to even propose anything about the
future fileformat.
But I would like to point out, that if the schematics, footprints are
splitted
into invidual files, the future file format are more easy to
implement, and
even the user can mix the new format and the old one! So the
transition could
be seamless and painless.
Implementation
--------------
I tried to propose the needed change in a way which are easy to implement
in small incemental steps.
Contribution and exporting a device
-----------------------------------
If somebody want to share their work with others or contribute back to
the project
the easiest way would be to have an export function from the program,
which
would make the following actions:
* Collect the informations about a device
(device file (description of the device), footprint file, schematic
file,
3dpackage file, datasheet)
* place the files into a temp directory with the device name, like bc547b
* zip the whole directory: bc547.zip
Versioning
----------
As all te device is handled as individual files, versioning is really
easy.
Just put all the files into svn, and all the history of a particular
package
are traced, and can diff between versions, contributors are traced too
for free.
So if there are any problem with a device (copyright infrigement or
anything),
to resolve an issue is simply remove the device, or revert the
appropriate
change of the device.
About me
--------
Im just somebody who wants to use KiCAD, and toying with the idea to
write a
package/schematic explorer in python and pygtk.
(or wxpython, if it turns out good, and the project wants to merge it)
Afterwords
----------
I hope that my words are not harsh (not my purpose). Im not
criticizing the project,
I just want to propose some ideas. If you read something inappropriate,
just ignore it (im not native english speaker).
All I want, is some brainstorming about the current situation.
Thank you really much for reading my proposal.
Best regards,
Khiraly
[1]:
Some personal experience: I have created a board (giant LED display),
there was two
device (SA40-19 100mm height led display, and tlp281, tlp281-4
optocoupler) which
not existed in KiCAD. I have created the schematic of the optocoupler and
the footprint of the led display, and optocoupler.
Now I wanted modify my board, and all the footprints have been
disappeared from
the modules library. Thx there is in my .brd file too, so I will be
able to
recover it using a text editor.
(I have finally recovered it, and I needed to add and remove my
libraries in cvpcb
several times along using text editor of course.)
Additional note: I use two computers (windowsXP at work, linux at home).
