nrf52840 ble disconnection issue

[EVOV Solutions]

Hi,

I have a medical device where my mother board has a NRF52840 chip which communicates with a Android Tablet through blue-tooth. We find it gets connected with few tablets & not with others. Following problems we see - 1) Getting connected through serial terminal manually & thereafter remains connected, 2) In other cases it connects and disconnects after say 20seconds

Can you suggest some solution for this?

Also, as my device runs on continuous main power, I want to run NR52840 on Class blue tooth...Is it possible to run it on classic blue tooth to maintain connectivity?

[Simonr]

Hi

Sorry, but I'll have to disagree. Can you share some information on what exactly your nRF52840 application is doing. If it uses BLE 5.0 features such as long range or tries to do an MTU update with sizes that BLE 4.0/4.2 etc. does not support, that might be a disconnect reason. 

The best way to see what is going on over the air would be to take a sniffer trace of what is going on over the air. That way we can see what packets are sent over the air, and what transaction is causing this disconnect. If you have a dedicated Bluetooth sniffer device like an Ellisys sniffer you can use that, or you can use an nRF52 DK or Dongle and the nRF Sniffer + Wireshark.

If that's not possible from your end, can you upload the log showing the disconnect on the tablet (and preferably the nRF52 side as well), that's usually better than a description. Also, if you could share what SDK and SDK version you're using that would help as well. There are too many possible root causes from the current description.

Best regards,

Simon

[EVOV Solutions]

Hi Simon,

We have a medical device, with a vital parameter monitoring console. NRF sends data to our Tablet(Display device) where it is displayed in a dashboard.

The console is fixed with each NRF PCB board i.e. there are no multiple devices connecting to the console.

 

We find issues with BLE connection with some tablets having BLE4.0/BLE5.0. We observe the connection is established through serial terminal(application) & it remains connected. This connection we have to establish manually through a command in serial terminal. The Tablet bluetooth does not get connected automatically.

 

 

In DWIN tablets we find even after serial terminal connection it disconnects after 20seconds.

 

Please let us know reasons & corrective action.