Doorbell is a good practical project to get going with! To get started, I'd recommend you to check out how the XBEE Transparent serial interface endpoint works ( http://exsilium.github.io/xbee-sdk-doc/group__xbee__transparent.html ). The following examples in the Codewarrior should help you get started:
The doorbell button
- WPAN / ZigBee / Transmit basic frames - Although the example is very easy, it shows how to send a frame using the transparent serial interface. Instead of sending the frame every second, tie this to your button press logic.
- Power Management / ZigBee / Wake up on packet receiving and on gpio press for transmitting. This example illustrates well how your doorbell button can be in sleep mode to save battery (it is probably planned to be a battery operated button, right?).
- WPAN / ZigBee / Basic frame reception - this example shows you how to process incoming frames. Even running this example as is, it should make the received frames show up on the serial interface as printouts. Just make sure you put the coordinator and the end-device to the same network.
Good luck and cheers!