Find a way to control Notify flow to prevent stock notify between device and phone App

[TTN]

Hi

We follow the chart to design our notify flow to control the data in notify queue.

but we face a problem, the data in the queue always get more than 2 when the 9 or 8 mins, then our flow stop to notify,

please reference the code below, s_not_send is the data in the queue.

We what to know how to deal with this issue to make to notify stable.

device information
SDK:14.2

SD:5.1.0 GATTS Handle Value Notification flow chart
Nordic Semiconductor Infocenter.pdf

	  if ( s_device_mode == e_only_data  ) {              
			if ( s_not_send < 3 ) {                          // if notify queue have 2 data， stop notify until under 2 data
	      err_code = ble_cus_custom_value_update( &m_cus, notify_data ) ;                                   
					if(err_code==8){
						SEGGER_RTT_printf(0,"process error err_code=8\n");
						  err_code = sd_ble_gap_disconnect( m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION ) ;
							s_not_send=0;
						  return ; 
					}				
        APP_ERROR_CHECK( err_code ) ;
				s_not_send++ ;
			} // if
		} // if

[TTN]

How can i find the answer?  I thought that there was a start to notify that the connection interval was accepted by the central.

[Vidar Berg]

TTN said:

I thought that there was a start to notify that the connection interval was accepted by the central.

It depends on your application. The SDK examples will typically terminate the link if the requested parameters are rejected after x attempts. You can check if you receive the BLE_CONN_PARAMS_EVT_SUCCEEDED from the connection parameters negotiation module.  

[TTN]

Yes, I check the event in the "on_conn_params_evt_hanlder" of main.c, I can get BLE_CONN_PARAMS_EVT_SUCCEEDED when use nrf connect to the custom device after I type the passkey to create a bonding connection.

the error is getting from sd_ble_gatts_hvx is 13, after the device start to notify for about 8~9 mins.

uint32_t ble_cus_custom_value_update(ble_cus_t * p_cus, uint8_t * custom_value)
{
    NRF_LOG_INFO("In ble_cus_custom_value_update. \r\n"); 
    if (p_cus == NULL)
    {
        return NRF_ERROR_NULL;
    }

    uint32_t err_code = NRF_SUCCESS;
    ble_gatts_value_t gatts_value;

    // Initialize value struct.
    memset(&gatts_value, 0, sizeof(gatts_value));

    gatts_value.len     = 20 ; 
    gatts_value.offset  = 0;
    gatts_value.p_value = custom_value;

    // Update database.
    err_code = sd_ble_gatts_value_set(p_cus->conn_handle,
                                      p_cus->custom_value_handles.value_handle,
                                      &gatts_value);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    // Send value if connected and notifying.
    if ((p_cus->conn_handle != BLE_CONN_HANDLE_INVALID)) 
    {
        ble_gatts_hvx_params_t hvx_params;

        memset(&hvx_params, 0, sizeof(hvx_params));

        hvx_params.handle = p_cus->custom_value_handles.value_handle;
        hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
        hvx_params.offset = gatts_value.offset;
        hvx_params.p_len  = &gatts_value.len;
        hvx_params.p_data = gatts_value.p_value;

        err_code = sd_ble_gatts_hvx(p_cus->conn_handle, &hvx_params);
	    SEGGER_RTT_printf( 0, "sd_ble_gatts_hvx result: %x. \r\n", err_code) ;
        NRF_LOG_INFO("sd_ble_gatts_hvx result: %x. \r\n", err_code); 
    }
    else
    {
        err_code = NRF_ERROR_INVALID_STATE;
        NRF_LOG_INFO("sd_ble_gatts_hvx result: NRF_ERROR_INVALID_STATE. \r\n"); 
    }


    return err_code;
}

[Vidar Berg]

Is the error value 0x13 or decimal 13?  0x13 corresponds to NRF_ERROR_RESOURCES and means that the output buffer is full: 

* @retval ::NRF_ERROR_RESOURCES Too many notifications queued.
* Wait for a @ref BLE_GATTS_EVT_HVN_TX_COMPLETE event and retry.

[TTN]

Hi, thanks for your reply, the error code is 0x13,

        err_code = sd_ble_gatts_hvx(p_cus->conn_handle, &hvx_params);
		if(err_code!=0){
			SEGGER_RTT_printf( 0, "sd_ble_gatts_hvx result: %x. \r\n", err_code) ;

so I used "s_not_send(self count data in queue)" to check whether I should call  sd_ble_gatts_hvx again, but the s_not_send didn't cut back so the device will keep waiting, user will feel the bluetooth stock.

	  if ( s_device_mode == e_only_data  ) {              
			if ( s_not_send < 3 ) {          // s_not_send=self count data in queue
	      err_code = ble_cus_custom_value_update( &m_cus, notify_data ) ;                                   
					if(err_code==8){
						SEGGER_RTT_printf(0,"process error err_code=8\n");
						err_code = sd_ble_gap_disconnect( m_conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION ) ;
					    s_not_send=0;
						return ; 
					}				
                APP_ERROR_CHECK( err_code ) ;
				s_not_send++ ;
			} // if
		} // if

 

how can I get the right available queue element number?
can I clear the queue to reset the available queue element?
is there any flow to handle this situation?