Digi International Inc.
802.15.4 Power Management using Cyclic Sleep example for mbed XBeeLib By Digi
Description
This example characterizes a device that needs to be continuously joined to the coordinator so
it doesn't lose any incoming packets. A fast response to packets is not required so radio can
sleep for some time to save power while the coordinator buffers its packets.
The example configures the radio to poll its coordinator every 5 seconds if there is any packet for it.
If there is one or more, it awakes and send the packets to the mbed micro-controller.
Setup
Network
You need to set up a coordinator in the network so it buffers the packets send to our local XBee device while it's sleeping.
A module configured as coordinator requires:
- 'Coordinator Enable (CE)' parameter set to 1.
- 'Coordinator Association (A2)' parameter set to 0x04 so the coordinator allows end device association.
- 'Cyclic Sleep Period (SP)' parameter set as the local XBee device.
In the example it is set to 5000 which represent 5000 ms or 5 seconds.
In the coordinator, when using X-CTU for configuration, the SP parameter has to be entered as the desired sleep time divided by 10 and in hexadecimal so to cope with the example it should be 5000 / 10 = 500 = 0x1F4 -> 1F4
- 'Time Before Sleep (ST)' parameter set as the local XBee device; 500 ms = 0x1F4.
Demo run
While it is running, send a packet to the device:
- Go to the "Console" tab of the XCTU connected to the coordinator.
- Press the "Add API frame to the list" button.
- Press "Create using API Frame generator" button.
- Select "802.15.4" protocol and "0x00 - Tx (Transmit) Request 64-bit address" Frame Type.
- Paste the Local XBee device 64-bit address in the "64-bit dest. address" text box. (You can copy it from the application banner).
- In the "RF data" text box, select the ASCII box and type "Hello XBee!".
- Press OK, Add Frame.
- Select the frame and press the "Send selected frame" button to send the frame ("Hello XBee!") to the XBee network.
Once the XBee device receives the frame, the radio will wake up to send it to mbed micro-controller, which will process and print the received data.
Verify that the XBee module has received the frame by accessing the serial console terminal. If it was successful, the "Hello XBee!" message will be displayed there.
After that, the radio will go to sleep again until new data is received.