Questions on customizing PCB using extra ports

Photon board provides some ports you can use easily. But according to the board pdf on github:

There are a lot of unused ports in the bottom area. I am wondering if it is possible to make use of those ports there when designing my own PCB board with Particle P1. Is there any specific cases I need to notice, or can I just the follow the usage of a normal STM32 board? And I would appreciate it if anyone could give some advices on customizing PCB board with Particle P1.


Do you mean the row of pins at the bottom of the STM32? Those are all the ground pins of the microcontroller.

I’m about to make a custom PCB for the Particle P1 modules also.

If your using Eagle Cad you can download the schematic and board design files for the P1 Red Board that Sparkfun created. It should get you going in the right direction.

Yes, thank you! Good to know that.

That is a great resource for PCB design. I will download it and check what is going on there.
Thank you!