在keyfobdemo例程中peripheral在广播状态的时候，灯会不停的闪。当与btool处于establish的时候，灯就会灭掉；当从establish状态到terminate时peripheral又会处于广播状态，灯又会开始闪。

看 peripheralStateNotificationCB函数中的GAPROLE_ADVERTISING和GAPROLE_CONNECTED事件中有Led的处理。

case GAPROLE_ADVERTISING:
      {
        // Visual feedback that we are advertising.
        HalLedSet( HAL_LED_2, HAL_LED_MODE_ON );
      }
      break;
      
    //if the state changed to connected, initially assume that keyfob is in range      
    case GAPROLE_CONNECTED:
      {
        // set the proximity state to either path loss alert or in range depending
        // on the value of keyfobProxIMAlertLevel (which was set by proximity monitor)
        if( keyfobProxIMAlertLevel != PP_ALERT_LEVEL_NO )
        {
          keyfobProximityState = KEYFOB_PROXSTATE_PATH_LOSS;
          // perform alert
          keyfobapp_PerformAlert();
          buzzer_beep_count = 0;
        }
        else // if keyfobProxIMAlertLevel == PP_ALERT_LEVEL_NO
        {
          keyfobProximityState = KEYFOB_PROXSTATE_CONNECTED_IN_RANGE;
          keyfobapp_StopAlert();
        }

        GAPRole_GetParameter( GAPROLE_CONNHANDLE, &connHandle );

        #if defined ( PLUS_BROADCASTER )
          osal_start_timerEx( keyfobapp_TaskID, KFD_ADV_IN_CONNECTION_EVT, ADV_IN_CONN_WAIT );
        #endif
          
        // Turn off LED that shows we're advertising
        HalLedSet( HAL_LED_2, HAL_LED_MODE_OFF );
      }
      break;