XBP24-DMWIT-250 Digi International, XBP24-DMWIT-250 Datasheet - Page 25

• Manufacturer Part Number: XBP24-DMWIT-250
• Description: XBEE-PRO MESH 2.4 EXTENDED
• Manufacturer: Digi International
• Series: XBEE-PRO™r

Specifications of XBP24-DMWIT-250

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: ISM
• Applications: General Purpose
• Power - Output: 18dBm
• Sensitivity: -100dBm
• Voltage - Supply: 2.8 V ~ 3.4 V
• Current - Receiving: 55mA
• Current - Transmitting: 250mA
• Data Interface: PCB, Through Hole
• Antenna Connector: On-Board, Wire Whip
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: Q4542387

XBee/XBee‐PRO DigiMesh 2.4 RF Modules
Sleeping Routers
Sleep Modes
The Sleeping Router feature of DigiMesh makes it possible for all nodes in the network to synchronize their sleep and wake times.
All synchronized cyclic sleep nodes enter and exit a low power state at the same time. This forms a cyclic sleeping network. Nodes
synchronize by receiving a special RF packet called a sync message which is sent by a node acting as a sleep coordinator. A node
in the network can become a sleep coordinator through a process called nomination. The sleep coordinator will send one sync
message at the beginning of each wake period. The sync message is sent as a broadcast and repeated by every node in the net-
work. The sleep and wake times for the entire network can be changed by locally changing the settings on an individual node.
The network will use the most recently set sleep settings.
There are three modes of operation:
Under most circumstances a network should consist of only nodes operating in the same sleep compatibility mode (Only SM0
nodes or only SM8 and SM7 nodes). Mesh route discovery and routing, are incompatible between normal nodes and sleep com-
patible nodes.
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•
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Operation
SM0 - Normal Mode (not sleep compatible)
SM7 - Sleep Support Mode (sleep compatible, not low power)
SM8 - Cyclic Sleeping Mode (sleep compatible, low power).
Normal mode is the default mode for a newly powered on node. In this mode a node will not sleep, but will synchro-
nize to a sleeping network. When synchronized, a normal node will relay sync messages generated by sleep compat-
ible nodes but will not generate sync messages. Once a normal node has synchronized with a sleeping network it
can be put into a sleep compatible sleep mode at any time.
A node in cyclic sleep mode sleeps for a programmed time, wakes in unison with other nodes, exchanges data and
sync messages, and then returns to sleep. While asleep, it cannot receive RF messages or read commands from the
UART port. Sleep and wake times are specified by the SP and ST of the network's sleep coordinator respectively. If
D9 = 1 (ON_SLEEP enabled) on a cyclic sleep node the ON_SLEEP line will assert when the module is awake and de-
assert when the module is asleep. CTS is also de-asserted while asleep (when D7 = 1).
An unsynchronized sleeping node, newly powered, will poll for a sync message and then sleep for the time specified
by SP, repeating the cycle until it becomes synchronized by receiving a sync message. Once a sync message is
received the node will synchronize itself with the network.
A node in sleep support mode will synchronize itself with a sleeping network but will not sleep. At any time the node
will respond with a sync message to new nodes in range which are attempting to join the sleeping network. A sleep
support node will only transmit normal data when the nodes in the sleeping network are awake.
Sleep support nodes are especially useful when used as preferred sleep coordinator nodes and as aids for adding
new nodes to a sleeping network.
One node in a sleeping network acts as the sleep coordinator. The process by which a node becomes a sleep coordi-
nator is described later in this document. At the beginning of a wake cycle the sleep coordinator will send a sync
message as a broadcast to all nodes in the network. This message contains synchronization information and the
wake and sleep times for the current cycle. All cyclic sleep nodes receiving a sync message will remain awake for
the wake time and then sleep for the sleep time specified.
The sleep coordinator will send one sync message at the beginning of every cycle with the values specified by its SP
and ST parameters for sleep time and wake time respectively. It should be noted that if SP or ST are changed the
Normal Mode (SM=0)
Cyclic Sleep Mode (SM=8)
Sleep Support Mode (SM=7)
Sync Messages
Note: Normal nodes are not compatible with nodes configured for sleep. Excepting the case of adding a
new node to a sleep compatible network, a network should consist only of normal nodes or only of sleep
compatible nodes.
Note: Because sleep support nodes do not sleep they should be mains powered.
© 2010 Digi International, Inc.
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