Characterize net label as active low signal

Until recently, I had the habit, to prepend net names that have active low logic with a ‘/’ character. Yet, the eeschema prohibits the entry of this character. However, older schematics with such net names (e.g. /CS) do not cause any problems. In a dialog box list of net names, these names simply get a double ‘/’. In pcbnew, no problems arises as well.

So my question ist: for what reason can the ‘/’ not be entered as part of the net name?

P.S. The reason for using the ‘/’ character is simple former experience. I believe it was with Orcad: A prepending ‘/’ resulted in a horizontal line over the whole label (in the schematic).

From eeschema manual…

Pin Overview

A pin is defined by its graphical representation, its name and its “number”. The pin’s “number” is defined by a set of 4 letters and / or numbers. For the Electrical Rules Check (ERC) tool to be useful, the pin’s “electrical” type (input, output, tri-state…​) must also be defined correctly. If this type is not defined properly, the schematic ERC check results may be invalid.

Important notes:

Do not use spaces in pin names and numbers.

To define a pin name with an inverted signal (overline) use the ~ (tilde) character. The next ~ character will turn off the overline. For example ~FO~O would display FO O.

If the pin name is reduced to a single symbol, the pin is regarded as unnamed.

Pin names starting with #, are reserved for power port symbols.

A pin "number" consists of 1 to 4 letters and/ or numbers. 1,2,..9999 are valid numbers. A1, B3, Anod, Gnd, Wire, etc. are also valid.

Duplicate pin "numbers" cannot exist in a symbol.
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Everyone has his/her own style when drawing schematics.

For net labelling, I prefer using the style CSEL(L) or WREN(H) just as examples. Advantage is, that they are portable between different packages/programs, as they use standard ASCII characters.

In KiCad you can prepend a tilde: “~” to use the inverting bar over the text that follows.

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I just tried it.
Then I checked the docs as well, and indeed I found it, however only under pin assignments of schematic symbols. Shortly after I found out that ‘/’ is no longer accepted, I already looked after the docs…
I’m still curious whether this feature is being present since a long time or not. On office, a computer is equipped with 4.0.7 and an old notebook still carries the latest stable 3.x Windows release…

Sure, it is present since the very beginning, at least before 2005 version. So no problems with pre-V4 versions, BZR4022 for example.

Correct, I just verified it with former stable BZR3256 (2012), which is on my old notebook. Docs notify it, too (pins related).

Tilde is an ASCII-character (#126).

Yes, I know, bad phrasing. The problem with tilde is that different programs and environments interpret it differently, which is not the case with ()

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