nRF52: Bluetooth + ZigBee, + 3-wire PTA for WiFi

[Steve-CP]

Hello,

I have a project that requires Bluetooth, Zigbee, and WiFi.

I want to make sure that the following is possible:

1. nRF52833 or nRF52840 can run Bluetooth and Zigbee stacks concurrently
2. With the above, also concurrently using the 3-wire PTA interface, whereby
   1. When either Bluetooth or Zigbee needs to transmit, PTA REQUEST line is asserted  
   2. The nRF radio only talks when the GRANT single is given by the external WiFi MCU

I understand that PTA has to be enabled in this fashion: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_radio_coex.html

Basically ,a lot of documentation references 2 way coexistence, I want be ensure that 3 way coexistence is possible.

[AHaug]

Hi,

I have picked up your case and I am working on it, however I will finish my reply to you within early next week after I have verified some facts with a colleague of mine who are returning from vacation. As for now, this is a reply to your first question: 

nRF52833 or nRF52840 can run Bluetooth and Zigbee stacks concurrently

Yes, ZigBee or Thread (802.15.4) can be combined with Bluetooth LE through multiprotocol support and we recommend you use the MPSL that we have made for this purpose. Both the nRF52833 and nRF52840 does support Bluetooth LE and ZigBee as seen in our Bluetooth LE SoC comparison matrix on this page. As for whether to choose one over the other, you will need to concider your applications needs with regards to functionality and features and how much storage you will need. The nRF52840 has as you can see there quite a bit more flash and RAM.

I will return with a reply to your second question as soon as I know more,

Kind regards,
Andreas

[Steve-CP]

Thank you for the information Andreas (sorry for my delayed response I was away from work for a week).

Getting answers on the other questions is still important to me.

[AHaug]

Hi,

I have been out of office the last week myself, so apologies for my delayed response.

My first thought was to make ZigBee and BLE work as according to the Multiprotocol support docs, and then go forth with Adding Wi-Fi Coexistence support to short-range radio applications, or to examine the MPSL for IEEE802.15.4 external radio coexistance as well as MPSL Bluetooth External Radio Coexistance, but neither explicitly states if 3-way coexistence of ZigBee, BLE and WiFi is possible.

The answer from our multiprotocol support team is that the 3-wire PTA interface run concurrently with Bluetooth and ZigBee stack is not currently supported. The issue here is that the Bluetooth stack and ZigBee/Thread stacks uses a different backend, which we plan to make the SDK support the same coex interface that ZigBee uses in a later release. This is expected to be "suited for development" in NCS v2.1, and production quality in a later release after that. When that happens, the 3-way coex will work between ZigBee and Bluetooth and 3-wire PTA

I hope this answers your question,

Kind regards,
Andreas

[Steve-CP]

Thank you. Yes that answers the question.