Problem with CCCD 2902

[Filya]

Hi

I have a problem with receiving / transmitting a packet of characteristics with a descriptor 2902 (CCCD 2902).
The principle of operation of my program is that the device on the peripheral side wakes up and falls asleep. At the time of waking up the central device (smartphone with Android OS) is connected to the peripheral device. If the connection is normal, then the peripheral device transmits the required number of packets and falls asleep.
The problem is that in some cases, the CCCD with the code 2902 is not sent from the Android side, which notifies that the transfer will be in the "notification" mode. Since the peripheral device did not receive cccd, it does not start sending data.

I assume that this is a problem on the android side, since there are no errors on the peripheral side. Am I guessing right? And can you explain what could be the problem?

The following are snapshots of logs that were made on the side of the phone (hci_snoop):

(lines: 187531 - cccd was sent; 187536 - a response was received from the peripheral device; 187544 - start receiving data.)

(lines: 187527 - personal data has been sent; 187530 - an answer was received that the data was successfully received.)

(lines: 188158 - 188163 - personal data was sent and a response was received, after that there is no cccd sending and the program hangs on it. This happens in a different connection.)

Chip: BT840F (analog nRF52840);

SDK: nRF5_SDK_15.2.0;

Softdevice: s132_nrf52_6.1.0_softdevice;

Android OS: 8.1.

Thanks in advance for your help.

[Simonr]

Hi

It's really hard to see what is wrong from what info you have provided here. But I agree that it seems the problem is on the Android side. I suggest you ask on an Android developer forum instead, as people there are likely more experienced with Android products. Our area of expertise is the Nordic products, chips, SoftDevice and SDKs, and not Android devices.

You should also be more specific on what you are trying to do and how you are doing it, as a Sniffer log with no knowledge on what the application is supposed to do is difficult to grasp.

Best regards,

Simon