HID reconnection problem

[David]

I'm trying to save power on my HID keyboard application by disconnecting the Bluetooth link after some time of inactivity. As soon as there are keystrokes to send, the device advertises again and sends the pending values.

Generally I have 8 chars to transmit at once, but in Android 7.1.1 (Nexus 5X) I often get only 7 or less. The first one or two characters seem to get lost, although there is no error event generated by my nRF8001. I even get the right number of data credit events, so I assume the values have been sent correctly. The second value (again 8 chars) is always transmitted entirely.

I always wait for the first pipe status event after reconnection, sending data right after the connected event makes it even worse.

How can I achieve a reliable transmission of my first value? Is there some event to tell me that the master device is fully ready to receive keystrokes? Has someone experienced a similar behaviour and found a workaround?

[run_ar]

Are you bonding to the peer? In this case you should be able to send notifications immediately after reconnecting.

If you are not bonded, you have to wait until the cccd's are enabled by the peer. However, you should get a PipeErrorEvent response from the nRF8001 if you try to send notifications when they are disabled. And I assume you see that the credits are used. Might be some issue with Android, so you have to wait for some time before sending the notifications. Do you have a sniffer trace that shows what is happening on air?