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?

[David]

OK, thank you for the information.

But how can I know that the encryption process has been successfully completed? The nRF8001 does not generate any events...

Edit: In another thread (devzone.nordicsemi.com/.../), I found that the nRF8001 generates a pipe status event after finishing encryption. Waiting for this event works for some devices, but not all. Specially iOS devices seem to ignore the first couple of notifications. What do I need to do to assure a reliable data transmission after HID reconnection?