Digi XBee Product Manual

XBee / XBee-PRO addressing
XBee / XBee-PRO RF Modules 802.15.4 Product Manual 28
XBee / XBee-PRO addressing
Every RF data packet sent over-the-air contains a Source Address and Destination Address field in its
header. The RF module conforms to the 802.15.4 specification and supports both short 16-bit
addresses and long 64-bit addresses. A unique 64-bit IEEE source address is assigned at the factory
and can be read with the SL (Serial Number Low) and SH (Serial Number High) commands. Short
addressing must be configured manually. A module will use its unique 64-bit address as its Source
Address if its MY (16-bit Source Address) value is “0xFFFF” or “0xFFFE.”
To send a packet to a specific module using 64-bit addressing: Set the Destination Address (DL + DH)
of the sender to match the Source Address (SL + SH) of the intended destination module.
To send a packet to a specific module using 16-bit addressing: Set DL (Destination Address Low)
parameter to equal the MY parameter of the intended destination module and set the DH
(Destination Address High) parameter to '0.'
Unicast Mode
By default, the RF module operates in Unicast Mode. Unicast Mode is the only mode that supports
retries. While in this mode, receiving modules send an ACK (acknowledgment) of RF packet reception
to the transmitter. If the transmitting module does not receive the ACK, it will re-send the packet up
to three times or until the ACK is received.
Short 16-bit addresses. The module can be configured to use short 16-bit addresses as the Source
Address by setting (MY < 0xFFFE). Setting the DH parameter (DH = 0) will configure the Destination
Address to be a short 16-bit address (if DL < 0xFFFE). For two modules to communicate using short
addressing, the Destination Address of the transmitter module must match the MY parameter of the
receiver.
The following table shows a sample network configuration that would enable Unicast Mode
communications using short 16-bit addresses.
Long 64-bit addresses. The RF module’s serial number (SL parameter concatenated to the SH
parameter) can be used as a 64-bit source address when the MY (16-bit Source Address) parameter is
disabled. When the MY parameter is disabled (MY = 0xFFFF or 0xFFFE), the module’s source address is
set to the 64-bit IEEE address stored in the SH and SL parameters.
When an End Device associates to a Coordinator, its MY parameter is set to 0xFFFE to enable 64-bit
addressing. The 64-bit address of the module is stored as SH and SL parameters. To send a packet to
a specific module, the Destination Address (DL + DH) on the sender must match the Source Address
(SL + SH) of the desired receiver.
Broadcast Mode
Any RF module within range will accept a packet that contains a broadcast address. When configured
to operate in Broadcast Mode, receiving modules do not send ACKs (acknowledgments) and
transmitting modules do not automatically re-sent packets as is the case in Unicast Mode.
Table 8: Sample Unicast Network Configuration (using 16-bit addressing)
Parameter RF Module 1 RF Module 2
MY (Source Address)
0x01 0x02
DH (Destination Address High)
00
DL (Destination Address Low)
0x02 0x01

Digi XBee Specifications

General

Operating Frequency	2.4 GHz
RF Data Rate	250 kbps
Model	XBee S2C
Category	Control Unit
Operating Voltage	2.1 to 3.6V DC
Operating Temperature	-40 to +85 °C
Interface	UART
Dimensions	24.38 x 27.61 x 9.14 mm