I have been working on a DMTD for quite some time. Till now, I’ve been using shunts and headers to select the bandwidth on each of the 2 channels. It’s time to add a switch for that function. I’ve selected a Grayhill 51P22-01-2-08N. It’s a 2-deck switch, but the decks do not share pin numbering. IOW deck 1 is pins 1-8 plus C1; deck 2 is pins 9-16 plus C2. I’ve downloaded the Samacsys symbol and footprint. The symbol is one single unit. Since I have two channels, each in their own sheet, I need to separate this symbol into two units, and delete the unused bits from each unit. Separating it into 2 units was easy. Kicad created 2 identical units. But how do I now do the surgery on each unit to remove the pins that are in the “other” unit from each unit? Every time I remove a pin, it’s removed in both units. I have clicked on the “All units are not interchangeable” button, but changes are still synchronized between the two units. Is this due to the fact that the symbol was already created when I decided to split it?
One of the things I tried was to “uncheck the NOT Interchangeable” button. That didn’t fix it.
After I posted, I decided to just hack away at it and see what I could come up with. So, I looked at the library for a 74LVC2G07 to find a working example. Next, I looked at the code in the symbol file. I noticed there were lines like this, which indicated the unit number for this part (I think). Pin 1 is in unit 1 and pin 5 is in unit 2. I don’t know what the second 1 in the “1 1” and “2 1” is for.
X ~ 1 -300 50 150 R 40 40 1 1 I
X ~ 5 -300 50 150 R 40 40 2 1 I
So, I modified the pins in the switch like this; where pin 8 is in unit 1 and pin 9 is in unit 2.
X 1-8 8 0 -700 200 R 50 50 1 1 P
X 2-1 9 0 0 200 R 50 50 2 1 P
This works, but it’s not the right way, and is a lot of effort. And just from these changes, the “synchronized pin edit mode” is disabled. I was not able to disable that button by pressing on it.
Before you start castigating me for hacking like this, I do understand the concern, and I had backups throughout the process. I would like to be able to do this the right way, though. I suspect it had something to do with just flipping a switch and expecting kicad to automatically turn it into 2 units. If flipping that switch is allowed for an existing part, it would seem to me that kicad needs to do more than just show you two identical units that are actually the same unit under the covers.
I’ve fumbled through the same muck before and I can’t recite the process exactly. I’m quite sure that checkbox is the key. It definitely works better when you do it right the first time
This is a device I downloaded from Mouser’s “Library Loader” and didn’t like. It’s a two-deck switch that mounts to a PCB, and they have the decks combined into one symbol. Not only that, but I wanted to flip one deck on the schematic, and their symbol was completely unflippable. LOL So, I changed it to make my schematic happy. I supposed I could have just rearranged all the components the switch connected to. Nah, that would have been too easy!
