De Morgan alternate symbols

[jmk]

@BobZ

So if we are just drawing op amp power pins differently or repositioning the two diodes in a common anode symbol, that is an equivalent symbol but is NOT a DeMorgan equivalent, right?

Right!
Two diodes with anodes common and a resistor tied to +, with respect to the cathodes, will have a DeMorgan equivalent, but two diodes with anodes common are just two diodes with anodes common however they are drawn.

[retiredfeline]

@BobZ

So if we are just drawing op amp power pins differently or repositioning the two diodes in a common anode symbol, that is an equivalent symbol but is NOT a DeMorgan equivalent, right?

Wait, maybe De Morgan did tinker with diodes in his spare time, and the historians just didn’t know.

[Piotr]

@BobZ

@ML9104

I generate a DeMorgan equivalent with swapped inputs

Not sure what you mean?

ML9104 writes about opamp symbol with power pins integrated. If you mirror such symbol along X to have + and - inputs swapped you get + supply at bottom and - at top. To avoid this he just makes DeMorgan (the name of flag in symbol definition) with + and - swapped.

[hmk]

So, if I understand correctly: Altium supports alternate symbol representations in general (not limited to De Morgan logic equivalents)?
And for KiCad there is code ready to merge, but the KiCad developer team refuses to have this new code and want to have only the De Morgan special case?

I’m not sure I quite understand why one would refuse alternate symbol representation ability, especially when code is already offered. (I could imagine that someone would find it tedious to implement if there is no code to begin with.)

[jmk]

@retiredfeline

Wait, maybe De Morgan did tinker with diodes in his spare time,

He died in 1871. Did they have diodes with which to tinker in those days?

[retiredfeline]

Ah you’re no fun.

[mgyger]

If I remember correctly, it’s limited to 100 alternative shapes in AD while KiCad 5’s internal structure and file format would have supported more (without changes). My understanding is that some KiCad developers felt it would complicate internals too much for themselves when they’ll eventually move to real databases for symbols and implement more DRC/ERC, and that the implementation they had in mind for them would solve it much better. Currently, I’m not attracted to their database solution at all (as a KiCad user I’m not a DBA), and I think it’s not aimed at the users that would use alternative symbol shapes either.

I guess it’s somewhat similar like with the autorouter; it’s too big for the current team to spend resources on it.

[jmk]

@retiredfeline

Ah you’re no fun

But I’m always trying.
I’ve often been told I’m trying.

[ML9104]

@BobZ

My key question/takeaway: If DeMorgan alternates are based on logic equations, isn’t it something of a misnomer to call my two BAW56 symbols DeMorgan variants?

I never said I like the name, but I don’t decide, that’s up to the KiCAD team.
“Alternate symbol” would work just as well and be more inclusive of other uses.

[BobZ]

Did he rectify the wrongs of the hysterical historians? What a pain in the anode!

[retiredfeline]

Now now, no need to get heater up about this.

[BobZ]

Well I have made an attempt to put an alternate symbol into my own library, and I am stuck. I am using 6.0. I had a look at:

Help creating De Morgan representation

I’m trying to create a De Morgan representation for the 74LS74. I go into the symbol editor, call up the 74LS74, click on “Edit symbol properties”, check the “Has alternate symbol (DeMorgan)” box, click OK, answer YES to the question, but then what? The “Show as DeMorgan…” buttons at the top are still disabled and if I again click on “Edit symbol properties” the “Has alternate symbol (DeMorgan)” box is now unchecked. But if I call up 74LS00, which already has a De Morgan representation, the “Sho…

and have a question similar to what a poster asks there. I am at this

and I do not know where to go from here??

[retiredfeline]

The next step is in the editor window. At the top you will find two buttons for the two graphics.

[BobZ]

Ahh! Bitten again by picture menus instead of verbal ones! (Note I did not say “symbol” menus. The double meaning is too uhhh uhhhh?)

That gets into the whole international thing. I am one of those monolingual English idiots. But what if the menu was in German or one of the many languages which I do not know? I often think that it would be easier to deal with that (I should be able to Google it!) then to look up a picture.

Anyway I am midway along taking advantage of this assisted Eureka! moment…

[BobZ]

Son of a turkey! It seems to work!

But I did cheat in one regard…I was working on BAT54C which in my library was already derived from my BAT54C-1. I could not figure out how to delete my BAT54C. So I zipped a copy of my diodes symbol library for backup, and then deleted the BAT54C using the notepad text editor. That seemed to work.

Then went back into KiCad and did a SAVE AS from BAT54C-1 to BAT54C. Then edited the properties and clicked the De Morgan box. Saved it. Went into my BAT54C-2 and copied all portions of that symbol into the scratchpad memory. Closed BAT54C, opened my BAT54C, clicked on the De Morgan alternate, deleted what was there and pasted what I had copied from the BAT54C-2. It sounds more complicated than it felt when doing it.

I would like to delete my BAT54C-1 and BAT54C-2 but I am probably using them in some designs…

[deKees]

I use deMorgan mainly for microprocessors. This makes it possible to get the I/O pins at the position where they are needed. Would be nice to have more than 2 variants.