beacon cannot work with uart

Question

I try to create a beacon which can receive dynamic UUID through UART and advertise with the received UUID. 
 Now I am working on the sample ble_app_uart, to replace the existed advertising codes with the beacon advertising code in ble_app_beacon. 
 But in practice, when I remove some code like below 
 APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_MAX_TIMERS, APP_TIMER_OP_QUEUE_SIZE, false);
 uart_init();
 buttons_leds_init(&erase_bonds);
 ble_stack_init();
 gap_params_init();
 services_init();
 //advertising_init();
 //conn_params_init();
 
 printf("%s",start_string);

 //init_timer();
 
 //err_code = ble_advertising_start(BLE_ADV_MODE_FAST);
 
 The program keep printing char 'ÿ', rather than print 'Start...' 
 How is it caused? And what should I do to implement my purpose?

yiran · Accepted Answer

I have solved the problem...
The reason of problem is my program doing nothing after initiation.
I change my code to this
APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_MAX_TIMERS, APP_TIMER_OP_QUEUE_SIZE, false); 
 err_code = bsp_init(BSP_INIT_LED, APP_TIMER_TICKS(100, APP_TIMER_PRESCALER), NULL);
APP_ERROR_CHECK(err_code);
uart_init();
//buttons_leds_init(&erase_bonds);
ble_stack_init();
//gap_params_init();
//services_init();
//advertising_init();
//conn_params_init();
advertising_beacon_init();
printf("%s",start_string);
	advertising_start();
 
 Where advertising_beacon_init and advertising_start are same to initiation function in ble_app_beacon, both beacon advertising and uart work well. 
 But I still hope someone can explain why program printed some strange things if it do nothing after initiation.