nRF52832 question

[Pawel Godlewski]

I am developing an android app which is connecting with this product. In that particular case my app advertises, the nRF scans and initiates connection with my app. Some phones connect easily, others struggle with keeping stable connection. Sometimes disconnect are pretty random, but what happens almost every time is when two phones try to connect to nRF with very low latency (30 ms) I get a disconnect from GATT for one of them. I am wondering if this product has any built-in solutions to prevent RF interference and creating a safe, interference-free connection with multiple devices in parralel?

[Kenneth]

You can find details here:
https://infocenter.nordicsemi.com/topic/sds_s132/SDS/s1xx/multilink_scheduling/priorities_and_events_intro.html

My suggestion is to setup each link one at a time, e.g.:

1. start advertising
2. wait for connection
3. wait for all exchanges (e.g. MTU / DLE) completes
4. wait for updated connection parameters (e.g. 30ms, slave latency 10)
5. wait for bonding and encryption if that is required
6. repeat from 1

Typically step 3-5 may just be replaced with a few seconds timeout between 2->1 again.

Best regards,
Kenneth

[Pawel Godlewski]

Thank you. Can I assume that unstable connections/disconnects can happen during connection process (with parallel connections) and that it cannot be prevented? Or maybe do you know of any solution that would help me fix that issue?

[Kenneth]

It's difficult to give an short answer here, since it would require on-air sniffer logs to understand what procedures from the peer that may require one link to temporary have higher priority, but if you follow my suggestion I think that is the most fail-safe (independent of what procedures the peer may be doing).

Best regards,
Kenneth

[Pawel Godlewski]

So the issue more likely may be caused  by how the android OS interprets master device requests or master device handles multiple peripherals rather than the app itself?

[Kenneth]

I don't think the app is the problem here no. I think it is mainly how the master device handle multiple peripherals that want to connect simultaneously. 

Best regards,
Kenneth