Minimum Schematic for P1 module

Hardware
1

I saw that the EAGLE files for the P1 (WM-N-BM-14) modules are up on Github. However, does anyone have a “Bare Minimum” schematic of a working design using the P1 module (preferably in EAGLE or just a PDF)? It seems like the P1 has more pins than the P0, so I’d like to make sure my design is ok before sending it to the fab.

Thanks in advance!

2

@ElementOrange,

The only missing piece is really a 3v3 power supply which you can see from - https://github.com/spark/photon as reference :wink:

  • 3V3 power supply
  • MODE and RESET button
  • RGB LED
3

The reset pin needs to be pulled high too. right?
You may also need a mode button either on or off board.

1 Like
4

I have a P1 reference design schematic that I can publish… the layout is not done though. I just used it for the P1 datasheet images. @mohit also created a P1 reference design with all of the pins broken out to headers, but the nets are not named as D0-D7, A0-A5, etc…

I could PM you the one I made… I’d rather not distribute it unrouted, but the schematic is good.

5

@BDub, did @mohit post his design cause I’ll love a copy of his! Ok, and your’s as well :smiley:

6

@BDub Thanks a lot! This looks a lot like mine (as I referenced the P0/Photon design). Only other question I had was about the BTCX_* pins. What is their purpose and do they need to be attached to anything?

Thanks for all the help and quick replies, guys - I really appreciate it.

7

@ElementOrange hopefully this will help explain it a bit, and no you don’t have to hook it up at all if you don’t need it:
http://docs.particle.io/photon/hardware/#2-6-external-coexistence-interface

8

@BDub, could you also PM me the P1 schematic you made? I think mine is very very close but I am still missing the following:

  • What does the testmode pin do?
  • Which pin is used for the USB_DISC?

I would really appreciate your help.

9

@bing1106 please see the schematic included in the

P1 Datasheet http://docs.particle.io/photon/p1-datasheet/

USB_DISC is automatically handled inside the STM32F205.
No need to hook up anything to testmode, it’s STM32 port pin PA8, which is defined as microcontroller clock output; capable of outputting a clock signal. I suppose you could use it as a GPIO if you needed an extra one.

3 Likes
10

@BDub thanks so much for putting this together! My design is now good to go!

1 Like
11

@BDub Thanks for the detailed datasheet! I did have one more question about the P1 in terms of board layout: Is it ok to leave the antenna portion of the P1 hanging off the side of a PCB (without any PCB underneath)? I see the land pattern for the P1 includes pads 74 and 75 - Do these need to be soldered down? I’m trying to save some board space…

Thanks in advance!

12

You’re welcome @ElementOrange :wink:

It’s a thin PCB and susceptible to being snapped off if not protected. If you are ok with that, then I’d say it’s probably ok to make a diving board :swimmer: out of it. I’d also be thinking about vibration, moisture and thermal affects. Probably a safe bet to stick the nickel worth of PCB under it for protection though.

13

Just to confirm, when looking at the schematic included in the P1 Datasheet http://docs.particle.io/photon/p1-datasheet/

the capacitors and wiring shown in section 6.4 are required and need to be on an external board i.e. are not already on the P1 module?

14

@whyameye, good question! Perhaps @BDub can clarify :smile:

15

@whyameye i believe that is a yes. Take the P1 like another IC chip. External bypass/decoupling caps will be needed :smile:

16

Ok but it isn’t a chip, it’s a module, so I’d love some confirmation on this from @BDub @BDub1

17

That is correct, caps are required :wink:

1 Like
18

@BDub can you share the eagle files of p1 reference design? do you have schematic as well as layout?

19

In the meantime… There’s also one here: https://www.sparkfun.com/products/13321

2 Likes
20

thank you @kennethlimcp this one helps

1 Like