how could we design samplelight device to control two or more light ？

You can process key event in zclsamplelight_event_loop. There is no need to have two event loop.

but when we register the zcl call back function，

is that like

  // Register the ZCL General Cluster Library callback functions
  zclGeneral_RegisterCmdCallbacks( SAMPLELIGHT1_ENDPOINT, &zclSampleLight_CmdCallbacks );

  // Register the ZCL General Cluster Library callback functions
  zclGeneral_RegisterCmdCallbacks( SAMPLELIGHT2_ENDPOINT, &zclSampleLight_CmdCallbacks );

static zclGeneral_AppCallbacks_t zclSampleLight1_CmdCallbacks =
{
  zclSampleLight1_BasicResetCB,            // Basic Cluster Reset command
  zclSampleLight1_IdentifyCB,              // Identify command
#ifdef ZCL_EZMODE
  NULL,                                   // Identify EZ-Mode Invoke command
  NULL,                                   // Identify Update Commission State command
#endif
  NULL,                                   // Identify Trigger Effect command
  zclSampleLight1_IdentifyQueryRspCB,      // Identify Query Response command
  zclSampleLight1_OnOffCB,                 // On/Off cluster commands
  。。。
};

static zclGeneral_AppCallbacks_t zclSampleLight2_CmdCallbacks =
{
  zclSampleLight2_BasicResetCB,            // Basic Cluster Reset command
  zclSampleLight2_IdentifyCB,              // Identify command
#ifdef ZCL_EZMODE
  NULL,                                   // Identify EZ-Mode Invoke command
  NULL,                                   // Identify Update Commission State command
#endif
  NULL,                                   // Identify Trigger Effect command
  zclSampleLight2_IdentifyQueryRspCB,      // Identify Query Response command
  zclSampleLight2_OnOffCB,                 // On/Off cluster commands
  。。。
};

anyway，there is not only ZCL callback function，but also a lot function need to be different with each endpoint，so i think if all control was used same task

that will be so complicated

What else do you need to be different for each endpoint?

yeah ，maybe there is not any more function need to be different with each endpoint，

void zclSampleLight_Init( byte task_id )
{
  zclSampleLight_TaskID = task_id;

  // Set destination address to indirect
  zclSampleLight_DstAddr.addrMode = (afAddrMode_t)AddrNotPresent;
  zclSampleLight_DstAddr.endPoint = 0;
  zclSampleLight_DstAddr.addr.shortAddr = 0;

  // This app is part of the Home Automation Profile
  zclHA_Init( &zclSampleLight_SimpleDesc );
  // This app is part of the Home Automation Profile
  zclHA_Init( &zclSampleLight1_SimpleDesc );
 
  // Register the ZCL General Cluster Library callback functions for light
  zclGeneral_RegisterCmdCallbacks( SAMPLELIGHT_ENDPOINT, &zclSampleLight_CmdCallbacks );
  // Register the ZCL General Cluster Library callback functions for light1
  zclGeneral_RegisterCmdCallbacks( SAMPLELIGHT1_ENDPOINT, &zclSampleLight1_CmdCallbacks );
 
  // Register the application's attribute list
  zcl_registerAttrList( SAMPLELIGHT_ENDPOINT, zclSampleLight_NumAttributes, zclSampleLight_Attrs );
  // Register the application's attribute list
  zcl_registerAttrList( SAMPLELIGHT1_ENDPOINT, zclSampleLight1_NumAttributes, zclSampleLight1_Attrs );
 
  // Register the Application to receive the unprocessed Foundation command/response messages
  zcl_registerForMsg( zclSampleLight_TaskID );

#ifdef ZCL_DISCOVER
  // Register the application's command list
  zcl_registerCmdList( SAMPLELIGHT_ENDPOINT, zclCmdsArraySize, zclSampleLight_Cmds );
  zcl_registerCmdList( SAMPLELIGHT1_ENDPOINT, zclCmdsArraySize, zclSampleLight1_Cmds );
#endif

  // Register for all key events - This app will handle all key events
  RegisterForKeys( zclSampleLight_TaskID );

  // Register for a sampleLight endpoint
  afRegister( &sampleLight_TestEp );
  // Register for a sampleLight1 endpoint
  afRegister( &sampleLight1_TestEp );
#ifdef ZCL_EZMODE
  // Register EZ-Mode
  zcl_RegisterEZMode( &zclSampleLight_RegisterEZModeData );

zcl_RegisterEZMode( &zclSampleLight1_RegisterEZModeData );

  // Register with the ZDO to receive Match Descriptor Responses
  ZDO_RegisterForZDOMsg(task_id, Match_Desc_rsp);
#endif

#ifdef ZCL_DIAGNOSTIC
  // Register the application's callback function to read/write attribute data.
  // This is only required when the attribute data format is unknown to ZCL.
  zcl_registerReadWriteCB( SAMPLELIGHT_ENDPOINT, zclDiagnostic_ReadWriteAttrCB, NULL );

 zcl_registerReadWriteCB( SAMPLELIGHT1_ENDPOINT, zclDiagnostic_ReadWriteAttrCB, NULL );

#endif
}

but i am curious about how could the ZC  knows  there are two endpoint on the new ZD while success joining the network？

i found that the structure of the zdoIncomingMsg_t which came from the  zclxxx_ProcessZDOMsgs( zdoIncomingMsg_t *pMsg )

typedef struct
{
  osal_event_hdr_t hdr;
  zAddrType_t      srcAddr;
  uint8            wasBroadcast;
  cId_t            clusterID;
  uint8            SecurityUse;
  uint8            TransSeq;
  uint8            asduLen;
  uint16           macDestAddr;
  uint8            *asdu;
  uint16           macSrcAddr;
} zdoIncomingMsg_t;

there is not any item about the endpoint info

hi yikai，

       when a device ZED joining the network， i could catch the  Device_annce，and i use ZDP_ActiveEPReq(&pMsg->srcAddr,pMsg->srcAddr.addr.shortAddr,0);

       but i could not catch Active_EP_rsp ，

      does it need to do something in the ZED side？

static void zclIASCIE_ProcessZDOMsgs( zdoIncomingMsg_t *pMsg )
{

  zclEZMode_ActionData_t data;
  ZDO_MatchDescRsp_t *pMatchDescRsp;
  ZDO_ActiveEndpointRsp_t *pActiveEndpoint;
 
  switch(pMsg->clusterID)
  {
      
  case Device_annce: // recevie a new device and pritnf its IEEE
  
    // get the endpiont of the devices 
    ZDP_ActiveEPReq(&pMsg->srcAddr,pMsg->srcAddr.addr.shortAddr,0);

     break;
 
  case Active_EP_rsp:
      pActiveEndpoint = ZDO_ParseEPListRsp( pMsg );
#ifdef UartShow
  HalUARTWrite(0,"Get ActiveEndpoint Success\n", sizeof("Get ActiveEndpoint Success\n"));
#endif

      osal_mem_free( pActiveEndpoint );
      break;      
  
  default:
    break;
     
  }
}