Modes Of Operation; Idle Mode; Transmit Mode - Digi XBee ZigBee S2D User Manual

If the above conditions do not apply (e.g. a sensor node, router, or a simple application), then transparent
operation might be suitable. It is acceptable to use a mixture of devices running API mode and transparent mode
in a network.

Modes of operation

Idle Mode

When not receiving or transmitting data, the RF module is in Idle Mode. The module shifts into the other modes of
operation under the following conditions:
•
Transmit Mode (Serial data in the serial receive buffer is ready to be packetized)
•
Receive Mode (Valid RF data is received through the antenna)
•
Sleep Mode (End Devices only)
•
Command Mode (Command Mode Sequence is issued, not available with Smart Energy software or when
using the SPI port)

Transmit Mode

When serial data is received and is ready for packetization, the RF module will exit Idle Mode and attempt to
transmit the data. The destination address determines which node(s) will receive the data.
Prior to transmitting the data, the module ensures that a 16-bit network address and route to the destination
node have been established.
If the destination 16-bit network address is not known, network address discovery will take place. If a route is not
known, route discovery will take place for the purpose of establishing a route to the destination node. If a module
with a matching network address is not discovered, the packet is discarded. The data will be transmitted once a
route is established. If route discovery fails to establish a route, the packet will be discarded. The following figure
shows the Transmit Mode sequence.
XBee/XBee-PRO ZigBee RF Modules User Guide
Modes of operation
34