Digi XBee S2C Zigbee User Manual page 154

Manage End Devices
its parent for data without waking an external device for an extended time (SP * SN time) as shown in
the following figure.
Note SP controls the packet buffer time on routers and coordinators. Set SP on all router and
coordinator devices to match the longest end device SP time. For more information, see
Router/Coordinator
Extended cyclic sleep
In extended cyclic sleep operation, an end device can sleep for a multiple of SP time which can extend
the sleep time up to several days. Configure the sleep period using the SP and SN commands. The
total sleep period is equal to (SP * SN) where SP is measured in 10ms units. The SO command must
be set correctly to enable extended sleep.
Since routers and coordinators can only buffer incoming RF data for their end device children for up
to 30 seconds, if an end device sleeps longer than 30 seconds, devices in the network need some
indication when an end device is awake before they can send data to it. End devices that use
extended cyclic sleep should send a transmission (such as an I/O sample) when they wake to inform
other devices that they are awake and can receive data. We recommended that extended sleep end
devices set SO to wake for the full ST time to provide other devices with enough time to send
messages to the end device.
Similar to short cyclic sleep, end devices running in this mode return to sleep when the sleep timer
expires, or when they receive the SI command.
Deep sleep
The following are preconditions for maintaining low current draw during sleep:
You must maintain the supply voltage within a valid operating range—2.1 to 3.6 V for the XBee,
n
3.0 to 3.6 V for the XBee-PRO (S2), 2.7 to 3. V for the XBee-PRO S2B.
Each GPIO input line with a pullup resistor which is driven low draws about 100 uA current
n
through the internal pullup resistor.
XBee/XBee-PRO® S2C Zigbee® RF Module User Guide
configuration.
End Device configuration
154