How to know that a BLE transfer is finished

[Aurele]

Hello,

I'm searching every where but i can't find what i want. Actually, i'm using two device and i really need to synchronise the execution of a process on both of them. 

So, the device n°1 send its request and execute the process. The device n°2 execute its process as soon as it receives the command. 

But, my probleme is that the device n°1 executes the process immediatly after the send function (i'm using ble_nus_c_string_send), and "ble_nus_c_string_send" returns the hand immediatly and doesn't wait to know if the frame has been really received by the other device. It there a way to know when the frame will be received by the other device before launching the execution of my process on my device n°1.

Best regards,

Aurélien

Here is my envrionment :

SDK : 15.3.0

SoftDevice : 6.1.1

IDE : Segger Embedded

[Aurele]

I found the following event : ​BLE_GATTC_EVT_WRITE_CMD_TX_COMPLETE

Maybe it is what i want !

[Edvin]

Yes. The BLE_GATTC_EVT_WRITE_CMD_TX_COMPLETE is the event you are looking for. It means that the connected device has ACKed the message that you sent. 

Note that you can't see what message that is acked, but if this is the only message that is sent, then that is it. 

[Aurele]

Thank you very much Edvin

Regards,