"fixing" the pin assignments on a symbol and footrpint


I downloaded the KCAD symbol and footprint libraries for a specialized chip from a distributor’s site. Note: NOT the manufacturer.

As i proceeded i realized that while they had the pin numbers assigned to the correct functions, the location numbering was wrong. The chip is numbers 1-10 on one side, goes across and then 11 to 20 with 1 and 20 across and 10 and 11 across.

The symbol library however had them 1-10, and 11-20 with 1 and 11 across and 10 adn 20 across - one row was therefore backward.

If i opened the symbol, and moved the 2nd row of pins to match the datasheet from MAXIM, am I good to go or need I do anything either between the footprint and symbol or to the footprint. The footprint is generic and simply shows 20 pads ( i need to figure out how to add an orientation dot).

Please confirm. I have made the change.


1 Like

Placement of pins on the symbol really doesn’t matter, many of us like to group them by function instead of physical placement on the part to make understanding the function of the schematic easier.

Your screenshot of the footprint doesn’t show the pin numbers so there isn’t any way to know if that is anywhere close to correct. (A 20pin dip is standard, so there should already be a footprint in the standard libraries that you could use.)

That said, there really isn’t much we can do without the datasheet. Would you provide a link to the datasheet for this part for us?

I think i have answered my own question. While they do not show up visibly, all the pads are numbered in the footprint - but those numbers are hidden adn there is no clue as to how to see them… This is about as hard to find as i can imagine! Wowzer - why is there not a command to “define pin numbers”?

In the symbol or the footprint?

The datasheet - as I wrote above - shows the numbering exactly like the corrected symbol that i included above. That is correct. NOT as it was done originally. (I reversed the physical position of pins 11-20)

That said, the 20 pin DIP footprint (also shown above) does apparently have embedded numbers - once i clicked on each pin, a data box opened, and did show a pin number, and those were in fact correct. So i’m good to go. But i mist say this was very intuitive to find!

you pointed out that no numbers are visible and you are right. How do i make them visible?

in the footprint. I obviously have pin numbers in the symbol.

If you look at the footprint in the Footprint Editor you can see the pin numbers. Here is a screenshot of the footprint called DIP-20_W7.62mm

If you want a table based editor for pin function for a symbol, in the Symbol Editor, the menu Edit/Pin Table… will get you something like this (I loaded a random IC for this screenshot):

You may want to change the pin types for the L, H, and W pins to passive instead of unspecified. The unspecified pin type will trigger ERC hits as its purpose is to be used as a reminder that you haven’t specified what the pin type is yet. Where passive is used for things like resistor (and potentiometer) pins.

The footprint doesn’t care what the pin functions are. Pin 1 in the symbol is Pin 1 in the footprint. Pin 2 in the symbol is Pin 2 in the footprint. Pin B3 (for a grid-numbered package like BGA) will connect to Pin B3 in the footprint.

Thanks for the help here.

But actually, on my system, no, that is not what i see.

The footprint i showed was a screen shot of the footprint editor’s depiction. It does NOT show the pin numbers.

How do i find the table you showed?

I get that. originally i could not find the pin number int he footprint at all since they are no visible.

however, now that i know they must be there, what you tell me i will see, and what i actually see, differ.

What version of KiCad are you running? I’m running v5.1.6-1

Also, if you zoom out enough in the footprint editor the pin numbers vanish (probably because they would be too small to render legibly).

5.1.2 MacOS

I’ll try zooming but its pretty big on my screen already.

edit: guess what? 2 more zooms and they show up.

I still cannot find that table but would like to make the change to “passive” tat you suggested.

That table that I showed you is in the Symbol Editor, for editing the symbol. Remember, the footprint doesn’t care about pin type or function. Only pin number, physical position, and pad geometry.

I guess I could see the pin numbers at a reasonable zoom because I have a 3200x1800 resolution on this Dell laptop. In mac world I guess that would be SuperRetina or something like that…

I found the “pin editor”. I am working on a travel laptop. 13" Low res - thsi is not my primary function so that is how it will continue… but now that i know the limitation i can deal with it.

Many thanks for your help.

No problem. Have fun with your project.

It would be worthwhile considering upgrading to a more recent version. There were a couple of quite significant bugs for macOS users that have been fixed between 5.1.2 and the latest version (5.1.6).

Hi John - Before I mess with my setup ( and since nothing seems to be a bug yet - all are intended (!) to work as they do)

  1. Does an upgrade preserve all my library pointers, settings etc.?
  2. Is there an in-progrma upgrade facility that is incremental (only touches updated modules)?



Hi Renee -

Yes,i foudn and read that. It pretty much answered my question well. The biggest problem at that point is that the pin numbers were not displaying in the footprint until i zoomed it to a not-easily-usable level. If even a hint of their presence had been there it would have been obvious…


The size of the pad number in the footprint depends on the size of the pad as it is ensured to always be rendered fully inside the pad.

My guess therefore is that something is fishy with your footprint (see the screenshot by @SembazuruCDE how it should look like)