append data before sending using ble_uart

Question

hi, i want to append data before sending. i am using ble_uart example. here suppose the data is available on uart buffer at 1data/sec. i want to sent some timer/counter which appends if there will be more data will be available in uart buffer. say 5data/per sencond then. i should be able to append all the data in a single packet.

currently i am using timeout to send data. here when i set timeout 500 ms (since 1000<500). then it send it porperly. but when the data is more say 5data/sec then program get restarted.

how should i approch the problem with approporate data appending before sending when there is more data available in uart buffer.

thanks!!

my code :

static void timer_handler(void * p_context)
        {
        		preCount++;
        		uint32_t err_code;
                //SEGGER_RTT_WriteString (0, "--> in timeout handler\n");
            	//SEGGER_RTT_printf (0, "preCount : %d\tIndex:%d\n",preCount,index);
        		SEGGER_RTT_printf(0, "Time Out. \n"); 
        		err_code = app_timer_stop(wait_timer_id);
        		APP_ERROR_CHECK(err_code);
        	
        		if((datacnt%3==0)&(preCount!=datacnt/3))
        			//SEGGER_RTT_printf (0, "preCount : %d\tcount:%d\tdatacnt:%d\n",preCount,count,datacnt);
        			SEGGER_RTT_printf (0, "Add Data\n");
        		else
        			SEGGER_RTT_printf (0, "Send all Data\n");
        			SEGGER_RTT_printf (0, "preCount : %d\tcount:%d\tdatacnt:%d\n",preCount,count,datacnt/3);
        				
        }
        
        // Create timers
        static void init_timers()
        {
            uint32_t err_code;
        	
        		// Initialize the Application timer Library.
            APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, false);
        		//SEGGER_RTT_printf(0, "APP_TIMER_INTI initialised. \n");
        
            // Create timers
            err_code = app_timer_create(&wait_timer_id,
                                        APP_TIMER_MODE_SINGLE_SHOT,
                                        timer_handler);
            APP_ERROR_CHECK(err_code);
        	
        		err_code = app_timer_start(wait_timer_id, APP_TIMER_TICKS(1500, APP_TIMER_PRESCALER), NULL);
        		APP_ERROR_CHECK(err_code);
        		//SEGGER_RTT_printf(0, "Timer Started \n");
        }
        
        
        /*@brief   Function for handling app_uart events.
         *
         * @details This function will receive a single character from the app_uart module and append it to 
         *          a string. The string will be be sent over BLE when the last character received was a 
         *          'new line' i.e '\n' (hex 0x0D) or if the string has reached a length of 
         *          @ref NUS_MAX_DATA_LENGTH.
         */
        /**@snippet [Handling the data received over UART] */
        void uart_event_handle(app_uart_evt_t * p_event)
        {
            static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
        		uint8_t data[5];
            static uint8_t index,push = 0;
        		//int index=0;
            uint32_t       err_code;
        
            switch (p_event->evt_type)
            {
                case APP_UART_DATA_READY:
                    UNUSED_VARIABLE(app_uart_get(&data_array[index]));
                    index++;datacnt++;
        						//preCount = index;
        						//SEGGER_RTT_printf(0, "index:%d\tprecnt:%d\n",index,preCount);
        						if(index%3 == 0)
        						{
        							count++;
        							//preCount = count;
        							init_timers();
        							
        							//preCount = count;
        							//SEGGER_RTT_printf(0, "index:%d\tprecnt:%d\tdatacnt:%d\n",index,preCount,datacnt);
        							//SEGGER_RTT_printf(0, "Application Timer Created. \n");
        							
        							
        							
        							//SEGGER_RTT_printf(0, "Data Count :%d\n",count);
        							//SEGGER_RTT_printf(0, "index :%d\n",index);
        							const uint8_t* midiData = parseMIDItoAppleBle(3, data_array);
        							for(int i=0;i<5;i++)
        							{
        								data[i] = midiData[i];
        							}
        							//SEGGER_RTT_printf(0, "%x\t%x\t%x\t%x\t%x\tCount:%d%tindex:%d\n",data[0], data[1],data[2],data[3], data[4],count, index);
        							
        								/*err_code = ble_nus_string_send(&m_nus, data, 5);
                        if (err_code != NRF_ERROR_INVALID_STATE)
                        {
                            APP_ERROR_CHECK(err_code);
                        }*/
        								//count++;
        								index = 0;
        						}						
        							
                    break;
    }