XB24-BPDK Digi International/Maxstream, XB24-BPDK Datasheet - Page 40

• Manufacturer Part Number: XB24-BPDK
• Description: KIT DEVELOPMENT XBEE SERIES 2
• Manufacturer: Digi International/Maxstream
• Series: XBee™r
• Type: 802.15.4/Zigbeer

Specifications of XB24-BPDK

• Frequency: 2.4GHz
• For Use With/related Products: XBee™ Series 2 Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

XBee ZNet 2.5/XBee‐PRO ZNet 2.5 ZigBee OEM RF Modules v1.x4x
On/Sleep
DIN
A cyclic sleep end device enters sleep mode when no serial or RF data is received for ST time.
Transmitting Poll
Request
On/Sleep
Figure 4‐015.Cylic Sleep
In cyclic sleep, the time the module sleeps for is dependent on several configuration commands –
SP, SN, and SO.
With SO set to 0 (no sleep options - default), the sleep period is defined as (SP * SN). Since the
parent can only buffer data up to 30 seconds, SP is settable up to 28 seconds. After SP expires,
the module wakes to send a poll request transmission to the parent to check for data. This helps
ensure the end device can receive RF data transmissions that were sent to it.
In many cases, the On/Sleep pin can be used to wake an external microprocessor or peripheral
device when the module wakes from sleep. If the end device wakes and finds that its parent had
no data, there may be no need to wake the external device. The SN command is a multiplier of
the SP time that determines how often to set the On/Sleep pin when waking. For example, if the
end device sleeps for 20 seconds, but the On/Sleep pin should only be set high on every 3rd poll
(once per minute), SN can be set to 3. The On/Sleep pin will be set high anytime RF data is
received, regardless of SN. This is shown in the figure below.
In some applications, the end device may transmit data at a very slow rate (once an hour, once a
day, etc) and will only receive data in response to its transmission. In such cases, the SO
command can be used to cause an end device to sleep for the entire SP * SN duration. This is
shown below.
Legend
© 2008 Digi International, Inc.
ST = Time Awake
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