How to enable the External Coexistence Interface?

Hi All,

I can’t seem to find info on enabling the External Coexistence Interface on the photon. I would like to use the pins with an external radio as described on the datasheet. I expected holding BTCX_RF_ACTIVE high would block the photon from transmitting, but I see no effect. I also expected to see BTCX_TXCONF go high intermittently giving the other radio permission to TX. The other radio behaves as expected when pulled high or low.

So my main question is, do I need to enable the signals somehow? And is the behavior I expect correct?

I did see the threads on trying to use the pins as GPIO but no direction on using them as defined.



There is virtually no information on how to use the external coexsistence interface, except for the few sentences in the documentation :frowning: . I too would like to know how to enable the coexsistence interface and use it with a bluetooth module. Maybe someone has an example on how this can be done?

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Hi, @natec007 and @itd24

Did you have any luck implementing the coexistence pins on your P1’s? I was expecting to use these pins on my project as well!

Could you share here any new information you have?

Can Particle provide a better description about how to use the coexistence pins found on P1, @BDub, @mdma, @ScruffR ? I looked into probably every post and there is no confirmation this even works, let alone a good working description. Are those pins even properly wired/configured by the P1’s firmware?


I’ve never got to the bottom of it - but I’m not an employee, so don’t have to :wink:

Sorry for including you, I didn’t realize you’re not part of their team. Let’s see if they had someone that ever made it work before. And thanks for your reply !

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Hey everyone!

Has anyone had success in getting the external coexistence interface to work yet? Still no updates to the datasheet, and it seems this has been an open question on multiple posts. If anyone has any examples on how to use this interface that would be super helpful.


Just checking in on this topic again. :slight_smile: @mdma or @BDub, is there any new info coming or released on how to use the coexistence interface? Thanks for the help!

Right now there is no working example of BT Co-ex on the Photon/P1. This would likely involve exposing some parts of the WICED SDK that we currently do not. There hasn’t been a big push for this feature which is why it tends to fall to the bottom of the priority list unfortunately. If any of you that are wanting this feature has time to dig into what is required, even from a high level, it would be appreciated. A github issue would also be a good place to capture the request.

There is a issue opened here:

The high level implementation should be very simple, there isn’t really much that can be done, it’s the Broadcom chip that actually coordinate the signals anyway.
I see some guys want to have those same pins available to extra IO’s. My suggestion is to just allowed the application to enable coexistence during setup:


Otherwise, one can use the pins for extra IO’s.

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Sorry despite my best efforts of wanting to do all of the things over holiday break, I ended up relaxing :slight_smile: I’ll see what can be done about bumping the priority of this up.


Hi @BDub, I’ve noticed that there was some work happening on github on the coexistence interface. Do you have any idea when this feature is planned for released? Looking forward to giving it a shot!



Hi @mattw, we’re currently working with Cypress on this to bring this feature to life. Keep an eye on that github issue to know when something starts to solidify :wink: Thanks!

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Awesome, will do! Thanks for the update!

Hey @BDub, I just wanted to check in to see if there were any more updates on this feature. Very eager to see it come to life! I haven’t seen any work on the github branch or issue in a while. Is this still being worked on / is there a release plan? Or has it been tabled for the time being? Thanks!