Symbol Editor, very nasty behaviour when editing symbol

Schematic Library Symbols
1

Case in point:
Editing a NAND gate and its associated DeMorgan equivalent the following happened:
I added power inputs to the NAND gate (top and bottom). No problem.
I did the same on the DeMorgan equivalent (OR with inverted inputs) in the same position. Also no problem, I thought.
(I always keep the pins in the same position to ensure interchangeability in the schematic).
Suddenly, the OR symbol with pins was shifted 0.25 mm to the right, and schematic connections would no longer attach to the symbol.

Turns out, the power inputs were connected to the “curved” part of the OR graphic, which the Symbol Editor didn’t like.
Instead of issuing a Warning or Error, it simply shifted the symbol position to the straight line section of it.

Cost me hours to find out. Not nice.

2

Would you like to rise a bug on the proper channels, adding screenshots and the version description?

1 Like
4

Seems like I’ve stuck my hand into a hornets’ nest here.
Also, I don’t know what the “proper channels” are. If it’s GitHub/GitLab, I wouldn’t touch it with a 20-foot pole.
I’ll retreat gracefully, I’ve solved the problem for myself, anyway.

5

I am mostly incompetent with Gitlab and/or Github but I have successfully introduced bugs there. Other capabilities sort of escape me. Raising the bug would do everyone a service…

6

Pardon my ignorance but what is a “DeMorgan equivalent”? You speak of it as being separate from the symbol.

John

7

Here is one explanation:

image
image882Ă—371 30.1 KB

I think of traditional gates as shown in the image, versus the rectangular ones with angled lines indicating inversion. Different symbols indicating the same illogical malfunction. :smiley:

8

Easy way: On KiCAD, go to Help menu and press “Report Bug”.

It fills the version info for you, so you just have to write the title and describe the bug (basically what you wrote here in the forum already and add any more images maybe)

9

Thank you. From the old ages I know the gist of DeMorgan’s theorem (from the dark ages). Just wasn’t seeing why one would need to create the non-standard version. Unless one was doing logic minimalization.

John

10

It increases clarity, readability and understanding of the functionality in a digital/logic schematic. Both for others and for yourself when you dig out the design after 3 years for review.
I use it extensively.

11

Forgeddit. Create user account, password etc. No Thanks.
I’ll leave GitLab to the geeks.

1 Like
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Who is calling who a GEEK!! If you are into DeMorgan symbols, you’re the geek.

Please…I am LOL…do not take me seriously. My point is that most of us here are geeks in one way or another…

2 Likes
13

Hahaha! I saw you confessing to GitLab incompetence earlier in the thread, so no offense taken.

But seriously: the DeMorgan function is great for making readable logic schematics.
As an example, check out this TI data sheet. It’s DeMorgan all over the place:
https://www.ti.com/lit/ds/symlink/sn74hc595.pdf

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