Receive the hrs data without enable notify

[helen]

Hi Nordic,

My customer has imploy nRF52832 to develop a heart rate equipment.

We have test the ble_app_hrs_c and ble_app_hrs on two nRF52 DK.

I found that if I comment out the notify enable function of the central, after the connection is established, the central will receive the heart rate data timely.

Why does this happen? We are quite confused.

[Einar Thorsrud]

Hi,

I am sorry for the late reply. I am not able to explain this, though. Have you made any changes to the two examples? Can you share your changes? Also, which SDK version are you using?

[helen]

Hi Thorsrud,

I use SDK17.0.2.

I havn't make any changes except comment out the notify enable function.

Maybe you can have a try with two DK board.

[Einar Thorsrud]

Hi,

I have tested with unmodified examples from SDK 17.0.2 and I am not able to reproduce what you have reported. With the call to ble_hrs_c_hrm_notif_enable() on line 539 in main.c commented out I only get notifications on battery level, as expected. However, if you have first tested with a firmware where ble_hrs_c_hrm_notif_enable() was not commented out, and then subsequently test with firmware that has it commented out, you will still get the notifications. As the devices are bonded and the peripheral (GATT server) remembers the state of the CCCD between connections. So you will receive notifications upon reconnection in this case whiteout explicitly enabling them. This is expected and intentional (and according to the Bluetooth specification).

Einar