Manage End Devices End Device configuration
XBee/XBee-PRO® S2C ZigBee® RF Module
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Command Range Description
SP 0x20 - 0xAF0 (x 10 ms)
(320 - 28,000 ms)
Configures the sleep period of the device.
SN
1 - 0xFFFF Configures the number of sleep periods multiplier.
SO
0 - 0xFF
Defines options for sleep mode behavior.
0x02 - Always wake for full ST time
0x04 - Enable extended sleep (sleep for full (SP * SN) time)
The device supports both a Short cyclic sleep and an Extended cyclic sleep that make use of these
commands. These two modes allow the sleep period to be configured according to the application
requirements.
Short cyclic sleep
In short cyclic sleep mode, define the sleep behavior of the device by the SP and SN commands, and
the SO command must be set to 0x00 (default) or 0x02. In short cyclic sleep mode, the SP command
defines the sleep period and you can set it for up to 28 seconds. When the XBee module enters short
cyclic sleep, it remains in a low power state until the SP time has expired.
After the sleep period expires, the XBee module sends a poll request transmission to its parent to
determine if the parent has any buffered data waiting for the end device. Since router and coordinator
devices can buffer data for end device children up to 30 seconds, the SP range (up to 28 seconds)
allows the end device to poll regularly enough to receive buffered data. If the parent has data for the
end device, the end device starts its sleep timer (ST) and continues polling every 100ms to receive
data. If the end device wakes and finds that its parent has no data for it, the end device can return to
sleep immediately.
Use the SN command to control when the On/Sleep line is asserted (high). If you SN to 1 (default), the
On/Sleep line sets high each time the XBee module wakes from sleep. Otherwise, if SN is greater than
1, the On/ Sleep line only sets high if RF data is received, or after SN wake cycles occur. This allows an
external device to remain powered off until it receives RF data, or until a number of sleep periods have
expired (SN sleep periods). This mechanism allows the XBee to wake at regular intervals to poll its
parent for data without waking an external device for an extended time (SP * SN time) as shown in
the following figure.
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