ANNOUNCEMENT: Introducing the Photon


Updated my post, I had 8MB not 8Mb. I was getting excited over the vast amount of flash, still an additional 1MB is nice to have. I’m going to really be thrilled with the 128kB SRAM!!!


We are designing our board for the Photon and very excited about receiving the units in March!! - not that far away. After reviewing the Photon schematics and eagle cad files on GitHub. I noticed U3 which is a RF switch is not outlined in the parts BOM. @BDub was the last author. Would it be possible to get that part identified? The files on github are more than 3 weeks old are there any updates? When do you think you will post the final designs? We are 8-10 weeks out from shipping the first units :smile:


Oh - yeah - one more thing. There is not any information about the P1, It would be very handy to get a datasheet, pin mappings, footprint, even better - an Eagle part. Will there be a reference design made available? Finally - there are still open questions about how the additional flash memory will be accessed, hopefully we can get this information soon so we can have boards ready when the parts arrive :wink: Thanks!


@BDub will be updating the repo soon! He and the hardware team are in China right now so they may not be the most responsive at the moment.


Right now we’ve only got a datasheet that’s under NDA from our module manufacturer; we’ll do our best to get this info distributed as soon as we can, but it may not be available until around shipping time.


@mtnscott please see the latest BOM for the Photon v0.1.0 just committed to the repo:


@BDub Thanks for the updated BOM. I’m still a bit confused, the eagle schematic, and all of the pictures of the Photon show a RF switch that is controlled via SW. That part does not show up on the BOM. I was hoping to prototype my board based on the P0 and was using the Photon as a reference design. It would be very helpful to have the latest BOM and Eagle files for the photon. With the photon shipping in March we are only about 8 weeks out, we don’t have much time to get our PCB’s manufactured.


Hi @mtnscott please try to clone a fresh copy of the Photon repo and check line 21 of the photon-bom-v010.xlsx, you should see the following:

Digikey link:


Hello! We had a bout of impatience here and decided to try to build a photon from the v001 layout. Perhaps this was a bad idea!
We’ve got a board assembled, but the vreg output is showing 0.87v at +3v3, and bypassing the regulator hasn’t brought us much joy either.
I don’t expect help troubleshooting our assembly, but perhaps someone could tell us this: is v001 tested and known to work?
thanks and regards from rainy London!


I’ll lateral that question to @BDub to answer for certain, although it’s fair to say that early revisions of our hardware have not necessarily been proven :smile:


Hi @mars the resistor divider on the v001 regulator is set to incorrect values on the schematic. It’s escaping me what the correct values are at the moment, but you only need to change one of them and you can get 3.3V up to 1A no problem. The regular completely changed between v001 and v010 though. The real problem with v001 is there are some power connections not hooked up on the USI module which are a pain to jumper :frowning: I would suggest building up v010 (photon_at7020_1) for the moment which has been through more testing. You’ll have to rotate the RGB led 90 CW though but it will connect to the cloud if you have proper keys generated. v011 has been generated internally which fixes the RGB LED connections and has a few other tweaks. We also have had the RF stage Pi filter matched to the antenna for best performance and will be updating the schematic with those values on v012. I’ll be getting v012 released this week if you want to wait to build that one stay tuned!


Ouch! So this would be VDDIO_WIFI, VDD_WIFI, and VDD_3V3? I can see now in the schematic and on the board that they don’t connect to power, but green-wiring the caps shouldn’t be too difficult. Worse to jumper the module…! We’ll try it out, while we wait for V012 :smile: Thanks for the information @BDub


Thanks @BDub, My implementation ends up with my antenna located inside on the PCB, all my edges are used up. Do you have any recommendations as to 1) how far away should I keep components, 2) any ground plane suggestions, and 3) different Pi filter settings.


If it’s any help to anyone else, to fix a v001 pcb you will have to:

  • change R2 from 100k to 10k to produce 3.3v at the regulator
  • jumper VDDIO_WIFI, VDD_WIFI, and VDD_3V3 to +3v3
    And probably, jumper the RGB_GREEN net to D7 to bring out SWDIO.

But: how is it programmed? I can’t find BOOT0 / BOOT1 in the pinout, and SWD doesn’t seem to work. Does it need a proper JTAG programmer rather than the stlink/v2 you get with the Discovery boards?

Also: is there a firmware repo already for the photon?


@BDub I think the Cree RGB LED part package PLCC4-2MM-RGB may be wrong. The footprint for the pads in the datasheet are 0.8mm tall by 1mm wide. In the Spark library on github the part’s pads are 1mm tall by 0.8mm wide. You may want to take another look at your package.


@BDub Any luck releasing the v012 schematic and board files?


I was going to ask the same thing! I guess spark hq is a busy place atm…


I saw the Photon can act as an access point. Is it possible to use it as a sort of base station access point and have multiple devices connect directly to it (such as mobile phones)?

I’d like to have the devices connected to it control some external hardware via the microcontroller over SPI or I2C.


Definitely possible :slight_smile:


@kennethlimcp Sweet - glad to here that! Thanks for the info.

Do you know what the maximum amount of connections to the Photon is, by any chance? Think 8 to 10 simultaneous connections is possible?