User's Manual

24 ProBee-ZE20S Series User Guide Rev.0.1
join the ZigBee network found automatically.
• Configure the settings for sleep interval.
Please refer to the section 3.2 Setting up ZE20S as a Router for the AT commands regarding the node
type selection through the PAN ID configurations.
One of the unique features of the ZigBee device is its extreme low power consumption which is mainly
achieved by its efficient sleep and wake-up mechanism. While ZigBee coordinator and routers are
required to be in operation always, ZigBee sleepy end devices can be configured to be in the sleep mode
most of the time and only wake up at pre-configured time interval for data transmission before it goes into
the sleep mode again. The ZE20S sleep interval can be configured by setting the S-registers using the AT
commands as below.
ATS51=n, where n is poll timeout in seconds and the default is 60.
This value is for a parent node. If an end device does not send a poll request to its parent coordinator or
router within the poll timeout, the end device is removed from the child table. Unlike the non-sleepy end
device, sleepy end device does not use S51 as the poll period. Instead, it uses S53 as the sleep duration
which works similar to the poll period, except it goes to sleep mode.
ATS53=n, where n is sleep duration in quarter seconds and the default is 8.
The ZE20S sleeps at sleep duration and turns off radio.
ATS52=n, where n is poll period in milliseconds and the default is 100.
Sleepy end device wakes up from the sleep mode if S53 timer expires or GPIO0 interrupt is generated or
serial data is received. Once the sleepy end device wakes up, it polls the parent node at poll period
defined by S52 until it goes to sleep mode again. Since the sleepy end device exchanges data with the
parent node only by polling, S52 poll period is usually configured as around 100 ms.
ATS54=n, where n is standby timeout in seconds and the default is 5.
If there is no RF data or serial data for S54 seconds, the sleepy end device goes to sleep mode again. If
any serial or RF data is sent or received, the timer will reset and the sleepy end device waits for another
S54 seconds before it goes to sleep mode again.
ATS55=n, where n is rejoin timeout and the default is 10.
When the connection to the parent node is broken for S55 in seconds, the child node tries to rejoin the
current network.