Why is the pin assignment different on the symbol vs physical board?

Hello Parmanu,

Thank you for reaching out.

I’ve forwarded your concern to the team to review the symbol and footprint for this part number. I’ll get back to you with updates as soon as possible.

Thanks again.

Hello Parmanu,

Thank you for your patience while we looked into this matter.

After reviewing, we couldn’t find any issues with the pin assignments—they are consistent with the datasheet.

Please note the following regarding the footprint:

The footprint includes two connectors: JP1 (bottom side) and JP3 (top side).

Pin 1 on JP1 starts from the bottom right corner and corresponds to IO21, as specified in the schematic document.

Pin 1 on JP3 starts from the top left corner and is connected to VBAT, again matching the schematic.

We’ve used the exact same pin names as listed in the schematic to maintain consistency. We hope this helps clarify the confusion.

I’ll also send you a few images via email to further explain the connector mounting on the module and the pinout for additional clarity.

Thank you.

Hi Amina,

I am admittedly new to KiCad, so I greatly appreciate your detailed response. I am trying to design a board for our research experiments, and I want to be thorough as usual. What I am reading between the lines is that the actual sequence of pins does not matter on the symbol as long as all of them are there. Is that correct?

Thank you!

Hello Parmanu,

You're very welcome—and you’ve got the right idea!

Yes, in general schematic design, the exact sequence of pins in the symbol doesn’t need to match the footprint order—as long as all pins are present and correctly numbered. That’s what really matters.

That said, there are some common practices engineers follow to keep schematics clean and intuitive. For example:

-Grouping pins by functionality is very common—for instance:
Inputs on the left
Outputs on the right
Power pins (e.g., VCC) on the top right
Ground pins (GND) on the bottom right

This layout helps maintain a logical flow in the schematic and makes debugging or reviewing much easier.

However, if you prefer to arrange the symbol pins in ascending order following the physical footprint (for consistency or personal preference), that’s also totally acceptable—especially if it helps you keep track of things more easily.

Feel free to reach out if you run into anything else. You're off to a great start!

Hi Amina,

I certainly will. Thank you for your support!