Data lost after disable and enable the notification

RE: Data lost after disable and enable the notification

Kenneth — Thu, 17 Sep 2020 07:58:23 GMT

Yes, that was what I meant yes.

Best regards,
Kenneth

RE: Data lost after disable and enable the notification

Tanglang — Thu, 17 Sep 2020 02:21:13 GMT

Hi, Kenneth

Thanks for your reply.

If we enable and disable notification dynamically, this problem happens.

The solution is to provide another characteristic that the central can write commands to acknowledge. After nRF52805 (ble peripheral) receives the characteristic with correct value/acknowledge, then sends the next piece of data.

Hope my understanding is correct. Thanks.

RE: Data lost after disable and enable the notification

Kenneth — Mon, 14 Sep 2020 14:23:11 GMT

Hi,

It is not common to enable and disable notification dynamically. Typically notification are enabled on initial connection, and then it's enabled for the remaining life time, this allow the peripheral device to send notification as it see fit to the central device. If you want to control the amount of data received on the central device, it is more common to add a characteristic that the central can write commands to, this may be commands to indicate to the application on the peripheral device to please send X notifications and/or start/stop sending notifications.

The problem with enabling and disabling notifications dynamically is that you quickly end up in race conditions between buffering of notifications on lower level in the stack and exactly when a notification is enabled/disabled on lower level compared to the state of the application.

Best regards,
Kenneth