Inconsistent transfer intervals

[JakeSprenger]

Hello,

I am using an nRF52 to transfer 20 bytes (through notifications) to a raspberry pi (with bluetooth dongle). I've been experiencing some weird connection times: I've attached a picture which shows what I am about to describe.

Every time the nRF52 sends a notification, the rPi reads it and logs the time interval between them. Usually, the interval is great - about half a millisecond. However, it occasionally jumps (randomly) to ~95 milliseconds. With my very limited knowledge of BLE protocol, I understand that this might be occurring due to the connection interval closing and re-opening. However, it seems to happen without any noticeable pattern. Any advice as to a) minimize this time delay or b) completely remove it would be appreciated. I am not even close to the maximum theoretical throughput, so I'm pretty confused as to why I'm getting bad results.

My current setup:

SDK v15.0

nRF52 running the BLE-peripheral tutorial on the Nordic Website

Any help is greatly appreciated.

[Marjeris Romero]

Hi,

The first thing I recommend you do is download and set up the nRF Sniffer for BLE:  https://infocenter.nordicsemi.com/topic/ug_sniffer_ble/UG/sniffer_ble/intro.html

Take a sniffer trace of the transfer, so you can check if the time interval between the packets correspond to the time interval registered by the Raspberry PI.

Best regards,

Marjeris

[JakeSprenger]

Thank you for the advice...I will give that a try!