Your config file looks ok.

I will check if errata 201 will solve your issues. I will try to send you a patch by this weekend.
As I will need to reproduce the issue, you will need to help me if it is the root cause. (with my DK, I did not see issues for hours before I had to be away from my desk).

- Vinayak

-----Original Message-----
From: <devel@...> on behalf of Randy Chou <rchou3@...>
Date: Wednesday, 7 November 2018 at 11:12 AM
To: "devel@..." <devel@...>
Subject: Re: [Zephyr-devel] #nrf52840 #ble unstable connection




    Hi Vinayak,
    I did some test today by using the latest master, there is no connection parameter update that means the CI keeps in 7.5ms, the connection keeps alive.
    I try to update the CI to 30ms manually the connection can keep around 6.5 mins.
    attachment is my .config file.

    Thanks,
    Randy