Footprint pin numbers: Is pin 0 legal?

I want to create a KiCad footprint for the Optek OPR2100 (6-element photodiode array). My usual practice is that the footprint pin numbers should match the datasheet numbering to avoid confusion.

This particular part has 13 pins, which are numbered on the data sheet from 0 to 12 (pin zero goes to an internal ground plane) http://optekinc.com/datasheets/opr2100.pdf

Does KiCad allow a pin #0, and if not, any suggestions on the best practice for pin numbering here? I’m tempted to just change Pin #0 to Pin #13 and leave the rest of the pins as labelled.

Thanks Andy_P. I’m a KiCad novice and I’d always used only positive pin numbers. I do see the “Footprint Editor” allows me to create Pin 0 and even negative pin numbers, but I’m not sure if that will get me into trouble elsewhere when I go on to use the part in a circuit, with routing etc.

Update: I see the “pad number” actually accepts any alphanumeric string of 4 characters or less, so apparently it’s not an issue. Unless I find a ten thousand pin chip… :slight_smile:

It is not treated as a number, it is a simple 4-character string so a huge array of possibilities exists. Where you might run into trouble is when you start exporting data for use with autorouters or other purposes.

cbernardo is correct. you can really put anything you want in there (up and including 4 characters), and if you are not exporting the design to an external tools you should be fine. You may still be fine exporting depending on the tool you are trying to interface with.

for BGAs and such, the pin numbers usually consist of letters and numbers, such as a1, b2, etc.

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Once discovering this I pretty much always use pin zero for shield connections. Also note that you can have multiple pads on the footprint with the same pin number. So I can have one schematic pin for the shield (pin zero, of course) and a foot print with 2, 4, or more pads for the shield, all with pin zero.

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