协调器关联表中的关联设备地址怎么全是0xffff

static void CheckAddr(void) {
  for (uint8 x=0;x<NWK_MAX_DEVICES;x++) {
    byte nr =  AssociatedDevList[x].nodeRelation;
    if (nr == CHILD_RFD) {

  //终端节点地址，数量可在此统计 

     //AssociatedDevList[x].shortAddr
    }}}

typedef struct
{
  uint16 shortAddr;                 // Short address of associated device
  uint16 addrIdx;                   // Index from the address manager
  byte nodeRelation;
  byte devStatus;                   // bitmap of various status values
  byte assocCnt;
  byte age;
  linkInfo_t linkInfo;
  aging_end_device_t endDev;
  uint32 timeoutCounter;
  bool keepaliveRcv;
} associated_devices_t;