Cyclic Sleep - Digi XBee S2C Zigbee User Manual

Manage End Devices
When the XBee/XBee-PRO Zigbee RF Module is awake and is joined to a network, it sends a poll
request to its parent to see if the parent has any buffered data. The end device continues to send poll
requests every 100 ms while it is awake.
Demonstration of pin sleep
Parent and remote devices must be configured to buffer data correctly and to use adequate
transmission timeouts. For more information, see

Cyclic sleep

Cyclic sleep allows the device to sleep for a specified time and wake for a short time to poll its parent
for any buffered data messages before returning to sleep again. Enable cyclic sleep mode by setting
the SM command to 4 or 5. SM5 is a slight variation of SM4 that allows the device to wake up
prematurely by asserting the Sleep_RQ pin(pin 10/SMT, pin 9/TH). In SM5, the XBee device can wake
after the sleep period expires, or if a high-to- low transition occurs on the Sleep_RQ pin. Setting SM to
4 disables the pin wake option.
In cyclic sleep, the device sleeps for a specified time, and then wakes and sends a poll request to its
parent to discover if the parent has any pending data for the end device. If the parent has buffered
data for the end device, or if it receives serial data, the device remains awake for a time. Otherwise, it
enters sleep mode immediately.
When the device wakes, it asserts (high) the On/Sleep line, and de-asserted (low) when the device
sleeps. If you enable hardware flow control (D7 command), the CTS pin asserts (low) when the device
wakes and can receive serial data, and de-assert (high) when the device sleeps.
The following figure shows the XBee sleep pins.
Surface-mount cyclic sleep pins
XBee/XBee-PRO® S2C Zigbee® RF Module User Guide
Router/Coordinator configuration.
End Device configuration
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