How to program the Zigbee series 2 module first with broadcast address and based on routing involved in the network how this broadcast address should be changed to one destination address?
The Broadcast address is 0xFFFF. Setting the DL to 0 and the DH to 0xFFFF will result in sending a broadcast packet.
For unicast, you set the DL and DH to mach the SL and SH of the node you want to receive the data.
See http://www.digi.com/support/kbase/kbaseresultdetl?id=2187