Symbol structure in the library file - Name and Value to be different


#1

My suggestion referred to the structure of the symbols in the library file.
Let’s have the look on the symbol structure at this moment:

CMP_NAME

DEF CMP_NAME C 0 40 Y Y 1 F N
F0 “C” 0 140 45 H V C CNN
F1 “CMP_NAME” 0 200 40 H I C CNN
F2 “C_0805” 0 -80 30 H V C CNN
F3 “” 0 -90 10 H V C CNN
F4 “1.8pF” 0 85 40 H V C CNN “Value2”
F5 “50V” 0 -125 30 H V C CNN “Voltage”
F6 “10%” 0 -170 30 H V C CNN “Tolerance”
DRAW
S -40 -50 -20 50 0 1 0 f
S 20 -50 40 50 0 1 0 f
X 1 1 -150 0 110 R 25 0 1 1 P
X 2 2 150 0 110 L 25 0 1 1 P
ENDDRAW
ENDDEF

The same information is in three different places:
here:

CMP_NAME

and here:
DEF CMP_NAME C 0 40 Y Y 1 F N

and here:
F1 “CMP_NAME” 0 200 40 H I C CNN

Why is this needed? I don’t know what to say.
But, in the symbol editor, I don’t understand why Kicad, when I create a symbol, don’t allow me to have different names for symbol Name (DEF field) and for Value (F1 field)?
However, after I placed the symbol in the schematic, Eeschema allows me to change the Value.

In this moment, this situation involve for me a double work to change the symbol Value, every time when a symbol is placed into a schematic. Do it one time in my life, it is not a problem, but when I have to do it 1000 times, it could be a problem.

In my opinion it will be a big advantage if symbol editor will allow me to have different names for Name and Value of the symbol.
For example, let’s have a scenario:
Create a new symbol with below Value: C_SMD_0805_1.8pF_50V_10%CeramicC0G_ID1802270001H
The symbol Name will be automatically chosen the same by the symbol editor:
C_SMD_0805_1.8pF_50V_10%CeramicC0G_ID1802270001H
And after the symbol will be placed in the schematic, I have to manually change above long Value with 1.8pF.
If the symbol editor will allow me to set the symbol Value and then, when the symbol is saved, it will ask be for symbol Name (as Footprint Editor does it), a lot of time will be saved when the component will be used in the schematic design.

This is a solution for the problem in below discussion: Symbol lib, same value but different name, how?

Many thanks!


#3

Yes this is a restriction of the current implementation of kicad. I assume this will change with the new file format that is expected to come with kicad 6 (It was originally planned for kicad 5 but lack of manpower meant it had to be pushed back.)


#4

I’ve been working with the new SWEET format, it’s not formally described in the spec but there is a value field. The examples show it with the same value as the part name, that may be a coincidence.

I’m trying to make a list of new features we’d like to see handled in the new format, so far I’ve got

ref/name position per unit
need to make power units mandatory
default footprint variants without duplicating whole symbol
pin swapping
groups of equivalent units?
default value different to part name

If there are others, let me know.


#5

I assume it will behave similarly to the footprint file format.
The footprints can have a default value field different to the footprint name.

In the official lib we require the value to be equal to the footprint name. This is mainly because it has always been that way. (No real need to change it) One valid reason might be that it makes reviewing based on screenshots easier. (Especially if there are multiple footprints in the pull request.)


#6

Thanks a lot to all of you for this info.

The reason behind, comes from a library generator.
So, I used a template for each type of symbol. Then I read a database where I saved my components with their parameters, and using a script file, I generated a library with one symbol for each components from the database and the symbol are already filled in with their parameters.
Then, in the schematic, I filter by parameters. For example, I searched by 100nF 10% 0805 and I will get all result, and when the component is placed in the schematic, it has all parameter already filled.


#7

You can do the same even with more then one symbol per lib.
You can look at this script to find out how you could insert symbols into an existing lib. https://github.com/KiCad/kicad-library-utils/blob/master/schlib/move_part.py

This would also allow you to have a bit more organization within kicad.


#8

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