How to receive BLE_EVT_TX_COMPLETE faster?

[Chocol8]

Greatings!

I am sending a packet with data in it from my custom board with nrf51822 to my android phone using cahnged ble_app_uart. The packet is being sent 8 times before I receive event BLE_EVT_TX_COMPLETE. Is it possibile to reduce time for receiving BLE_EVT_TX_COMPLETE or could you suggest how to wait for this event so I would not be sending 8 packets? This is where I set event flag:

case BLE_EVT_TX_COMPLETE:
        ble_tx_complete = 1;					
	    break;

Is device is connected I am sending a string while I will get an event flag:

if( m_conn_handle != BLE_CONN_HANDLE_INVALID ) // BLE is connected. Do service routine.
	 {					
	  if(ble_tx_complete == 0) 
	    {
	      sprintf((char*)siusti_plnasete0,"H:%.2f T:%.2f",BME280_humidity,BME280_temperature);
	      ble_nus_send_string(&m_nus,siusti_plnasete0,20);
            }
	 }

This is how it looks in nrf_uart app:

I have tried this way but then phone do not receive that packet at all:

 if( m_conn_handle != BLE_CONN_HANDLE_INVALID ) // BLE is connected. Do service routine.
    	 {					
    	
    	      sprintf((char*)siusti_plnasete0,"H:%.2f T:%.2f",BME280_humidity,BME280_temperature);
    	      ble_nus_send_string(&m_nus,siusti_plnasete0,20);
                 while(ble_tx_complete == 0) 
    	       {
                   }
    	 }

Any suggestions?

-----------------------EDIT----------------------------------------------- This is real time trace from wireshark:

I use s110 (7.0.0), I can not find which SDK example I took. Is there a way to find from which sdk it was taken somewhere in a project? But I believe its one of 5,6 or 7.

[run_ar]

Not sure I understand the problem here. But why would you use the tx_complete event to determine when to send another packet? I.e. If you only want to send the packet once, you should only call the sd_ble_gatts_hvx one time. The packet is buffered in the SD until it's received by the peer or the connection is disconnected.

If you want to send one packet per connection event you could use radio notifications to let your application know when to prepare the next packet.

If you want to send data as fast as possible, just loop through your date until the Softdevice buffers are full (7 or 6 if you sent packets in the previous connection event.)

[endnode]

No, I haven't said and I don't think you will never get TX_COMPLETE event. There is actually no other way to know that something happened on GATT layer in outbound direction so you should keep using it (the only other way would be to "shoot into the dark" by simply trying to put more outgoing notifications any time your BLE event handler is triggered by any event or based on some timer). The only thing I said is that you shouldn't expect as many TX_COMPLETE events as many packets you pushed because some of them may go through within one connection interval where there is no time for application processing between PDUs processed by Soft Device. I would simply expect that stack will trigger you as soon as at least one TX slot emptied and there is any time for APP layer processing.

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