I am using RN4871 with the latest firmware to turn on multiple LEDs via an I2C LED driver. I use gattlib C/C++ library to communicate ("write without response") with the RN4871 through my Ubuntu (20.04) system and I measure the latency of communication via an oscilloscope connected both to my computer and the RN4871. I set the communication parameters on the Bluetooth device to 7.5 ms intervals with zero latency.
The problem is if I send commands from my computer in 500ms intervals, my communication latency is below 20ms which is just perfect for my application. However if my commands are 1 seconds or longer apart the latency rises up to 250ms! In my application I need extremely fast communications with minimal latency (below 40ms) and of course my commands are sent at variable intervals (can be even 10 seconds apart). I dont know where this issue comes from? Does it have to do with some sleeping process within the RN4871 that occurs when there is no data to transfer for more than 500ms or something else?
Thanks!