Digi XBee User manual

Digi International Inc.
11001 Bren Road East
Minnetonka, MN 55343
877 912-3444 or 952 912-3444
http://www.digi.com
XBee®/XBee-PRO®RF Modules
XBee®/XBee-PRO®RF Modules
RF Module Operation
RF Module Configuration
Appendices
Product Manual v1.xEx - 802.15.4 Protocol
For RF Module Part Numbers: XB24-A...-001, XBP24-A...-001
IEEE®802.15.4 RF Modules by Digi International
90000982_P
6/3/2014

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc. ii
© 2014 Digi International Inc. All rights reserved.
Thecontentsofthismanualmaynotbetransmittedorreproducedinanyformor
byanymeanswithoutthewrittenpermissionofDigiInc.
XBee®andXBee‐PRO®areregisteredtrademarksofDigiInc.
Technical Support: Phone: [phone] toll-free U.S.A. & Canada
[phone] Worldwide
8:00 am - 5:00 pm [U.S. Mountain Time]
Online Support: http://www.digi.com/support/eservice/login.jsp
Email: [email protected]m

Contents
XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc.iii
1. XBee®/XBee-PRO® RF Modules 4
Key Features of the XBee/XBee-PRO Modules
4Worldwide Acceptance 4
Specifications of the XBee/XBee-PRO RF Mod-
ule 5
Mechanical Drawings of the XBee/XBee-PRO
RF Module 6
Mounting Considerations of the XBee/XBee-
PRO RF Module 6
Pin Signals for the XBee/XBee-PRO RF Module
7
Design Notes for the XBee/XBee-PRO RF Mod-
ule 7
Power Supply Design 7
Recommended Pin Connections 8
Board Layout 8
Antenna Performance 8
Electrical Characteristics of the XBee/XBee-
PRO RF Module 10
2. XBee/XBee-PRO RF Module Operation 12
Serial Communications of the XBee/XBee-PRO
RF Module 12
UART Data Flow 12
Transparent Operation 13
API Operation 13
Flow Control 14
ADC and Digital I/O Line Support of the XBee/
XBee-PRO RF Module 15
I/O Data Format 15
API Support 16
Sleep Support 16
DIO Pin Change Detect 16
Sample Rate (Interval) 16
I/O Line Passing 17
Configuration Example 17
XBee®/XBee-PRO® Networks 18
Peer-to-Peer 18
NonBeacon (w/ Coordinator) 18
Association 19
XBee®/XBee-PRO® Addressing 22
Unicast Mode 22
Broadcast Mode 22
Modes of Operation for the XBee/XBee-PRO RF
Modules 23
Idle Mode 23
Transmit/Receive Modes 23
Sleep Mode 25
Command Mode 27
3. XBee/XBee-PRO RF Module Configuration28
Programming the RF Module 28
Programming Examples 28
Remote Configuration Commands 29
Sending a Remote Command 29
Applying Changes on Remote 29
Remote Command Responses 29
Command Reference Tables 29
Command Descriptions for the XBee/XBee-
PRO RF Module 37
API Operation for the XBee/XBee-PRO RF
Module 58
API Frame Specifications 58
API Types 59
4. Agency Certifications 65
United States (FCC) 65
OEM Labeling Requirements 65
FCC Notices 65
FCC-Approved Antennas (2.4 GHz) 66
Approved Antennas 69
Canada (IC) 69
Labeling Requirements 69
Japan 69
Labeling Requirements 69
5. Additional Information 71
1-Year Warranty 71

©2014DigiInternationalInc. 4
1.XBee®/XBee‐PRO®RFModules
The XBee and XBee-PRO RF Modules were engineered to
meet IEEE 802.15.4 standards and support the unique
needs of low-cost, low-power wireless sensor networks.
The modules require minimal power and provide reliable
delivery of data between devices.
The modules operate within the ISM 2.4 GHz frequency
band and are pin-for-pin compatible with each other.
Key Features of the XBee/XBee-PRO Modules
Worldwide Acceptance
FCC Approval (USA) Refer to Appendix A [p65] for FCC Requirements.
Systems that contain XBee®/XBee-PRO® RF Modules inherit Digi Certifications.
ISM (Industrial, Scientific & Medical) 2.4 GHz frequency band
Manufactured under ISO 9001:2000 registered standards
XBee®/XBee-PRO® RF Modules are optimized for use in the United States, Canada,
Australia, Japan, and Europe. Contact Digi for complete list of government agency
approvals.
Long Range Data Integrity
XBee
• Indoor/Urban: up to 100’ (30 m)
• Outdoor line-of-sight: up to 300’ (90 m)
• Transmit Power: 1 mW (0 dBm)
• Receiver Sensitivity: -92 dBm
XBee-PRO
• Indoor/Urban: up to 300’ (90 m), 200' (60 m) for
International variant
• Outdoor line-of-sight: up to 1 mile (1600 m), 2500'
(750 m) for International variant
• Transmit Power: 63mW (18dBm), 10mW (10dBm)
for International variant
• Receiver Sensitivity: -100 dBm
RF Data Rate: 250,000 bps
Advanced Networking & Security
Retries and Acknowledgements
DSSS (Direct Sequence Spread Spectrum)
Each direct sequence channels has over
65,000 unique network addresses available
Source/Destination Addressing
Unicast & Broadcast Communications
Point-to-point, point-to-multipoint 
and peer-to-peer topologies supported
Coordinator/End Device operations
Transparent and API Operations
128-bit Encryption
Low Power
XBee
• TX Peak Current: 45 mA (@3.3 V)
• RX Current: 50 mA (@3.3 V)
• Power-down Current: < 10 µA
XBee-PRO
• TX Peak Current: 250mA (150mA for interna-
tional variant)
• TX Peak Current (RPSMA module only):
340mA (180mA for international variant)
• RX Current: 55 mA (@3.3 V)
• Power-down Current: < 10 µA
ADC and I/O line support
Analog-to-digital conversion, Digital I/O
I/O Line Passing
Easy-to-Use
No configuration necessary for out-of box
RF communications
Free X-CTU Software
(Testing and configuration software)
AT and API Command Modes for 
configuring module parameters
Extensive command set
Small form factor

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc. 5
Specifications of the XBee/XBee-PRO RF Module
*SeeAppendixAforregion‐specificcertificationrequirements.
Antenna Options: The ranges specified are typical when using the integrated Whip (1.5 dBi) and Dipole (2.1 dBi) anten-
nas. The PCB antenna option provides advantages in its form factor; however, it typically yields shorter range than the
Whip and Dipole antenna options when transmitting outdoors.For more information, refer to the "XBee Antennas” Knowl-
edgebase Article located on Digi's Support Web site
Table1‐01. SpecificationsoftheXBee®/XBee‐PRO®RFModules
Specification XBee XBee-PRO
Performance
Indoor/Urban Range Up to 100 ft (30 m) Up to 300 ft. (90 m), up to 200 ft (60 m) International
variant
Outdoor RF line-of-sight Range Up to 300 ft (90 m) Up to 1 mile (1600 m), up to 2500 ft (750 m)
international variant
Transmit Power Output
(software selectable) 1mW (0 dBm) 63mW (18dBm)*
10mW (10 dBm) for International variant
RF Data Rate 250,000 bps 250,000 bps
Serial Interface Data Rate
(software selectable) 1200 bps - 250 kbps (non-standard baud rates also supported) 1200 bps - 250 kbps (non-standard baud rates also supported)
Receiver Sensitivity -92 dBm (1% packet error rate) -100 dBm (1% packet error rate)
Power Requirements
Supply Voltage 2.8 – 3.4 V 2.8 – 3.4 V
Transmit Current (typical) 45mA (@ 3.3 V) 250mA (@3.3 V) (150mA for international variant)
RPSMA module only: 340mA (@3.3 V) (180mA for
international variant)
Idle / Receive Current (typical) 50mA (@ 3.3 V) 55mA (@ 3.3 V)
Power-down Current < 10 µA < 10 µA
General
Operating Frequency ISM 2.4 GHz ISM 2.4 GHz
Dimensions 0.960” x 1.087” (2.438cm x 2.761cm) 0.960” x 1.297” (2.438cm x 3.294cm)
Operating Temperature -40 to 85º C (industrial) -40 to 85º C (industrial)
Antenna Options Integrated Whip Antenna, Embedded PCB Antenna,
U.FL Connector, RPSMA connector Integrated Whip Antenna, Embedded PCB Antenna, U.FL Connector, RPSMA connector
Networking & Security
Supported Network Topologies Point-to-point, Point-to-multipoint & Peer-to-peer
Number of Channels
(software selectable) 16 Direct Sequence Channels 12 Direct Sequence Channels
Addressing Options PAN ID, Channel and Addresses PAN ID, Channel and Addresses
Agency Approvals
United States (FCC Part 15.247) OUR-XBEE OUR-XBEEPRO
Industry Canada (IC) 4214A XBEE 4214A XBEEPRO
Europe (CE) ETSI ETSI (Max. 10 dBm transmit power output)*
Japan R201WW07215214 R201WW08215111 (Max. 10 dBm transmit power
output)*
Wire, chip, RPMSA, and U.FL versions are certified for
Japan. PCB antenna version is not.
Australia C-Tick C-Tick

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc. 6
Mechanical Drawings of the XBee/XBee-PRO RF Module
Figure1‐01. MechanicaldrawingsoftheXBee®/XBee‐PRO®RFModules(antennaoptionsnotshown)
TheXBeeandXBee‐PRORFModulesarepin‐for‐pincompatible.
Mounting Considerations of the XBee/XBee-PRO RF Module
The XBee®/XBee-PRO® RF Module was designed to mount into a receptacle (socket) and there-
fore does not require any soldering when mounting it to a board. The XBee Development Kits con-
tain RS-232 and USB interface boards which use two 20-pin receptacles to receive modules.
Figure1‐02. XBeeModuleMountingtoanRS‐232InterfaceBoard.
The receptacles used on Digi development boards are manufactured by Century Interconnect.
Several other manufacturers provide comparable mounting solutions; however, Digi currently uses
the following receptacles:
• Through-hole single-row receptacles - 
Samtec P/N: MMS-110-01-L-SV (or equivalent)
• Surface-mount double-row receptacles - 
Century Interconnect P/N: CPRMSL20-D-0-1 (or equivalent)
• Surface-mount single-row receptacles - 
Samtec P/N: SMM-110-02-SM-S
Digi also recommends printing an outline of the module on the board to indicate the orientation the
module should be mounted.

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc. 7
Pin Signals for the XBee/XBee-PRO RF Module
Figure1‐03. XBee®/XBee‐PRO®RFModulePin
Numbers
(topsidesshown‐shieldsonbottom)
*Functionisnotsupportedatthetimeofthisrelease
Notes:
• Minimum connections: VCC, GND, DOUT & DIN
• Minimum connections for updating firmware: VCC, GND, DIN, DOUT, RTS & DTR
• Signal Direction is specified with respect to the module
• Module includes a 50k pull-up resistor attached to RESET
• Several of the input pull-ups can be configured using the PR command
• Unused pins should be left disconnected
Design Notes for the XBee/XBee-PRO RF Module
The XBee modules do not specifically require any external circuitry or specific connections for
proper operation. However, there are some general design guidelines that are recommended for
help in troubleshooting and building a robust design.
Power Supply Design
Poor power supply can lead to poor radio performance, especially if the supply voltage is not kept
within tolerance or is excessively noisy. To help reduce noise, we recommend placing a 1.0 µF and
8.2 pF capacitor as near as possible to pin 1 on the XBee. If using a switching regulator for the
power supply, switching frequencies above 500 kHz are preferred. Power supply ripple should be
limited to a maximum 100 mV peak to peak.
Table1‐02. PinAssignmentsfortheXBeeandXBee‐PROModules
(Low‐assertedsignalsaredistinguishedwithahorizontallineabovesignalname.)
Pin # Name Direction Description
1 VCC - Power supply
2 DOUT Output UART Data Out
3 DIN / CONFIG Input UART Data In
4 DO8* Output Digital Output 8
5RESET Input Module Reset (reset pulse must be at least 200 ns)
6 PWM0 / RSSI Output PWM Output 0 / RX Signal Strength Indicator
7 PWM1 Output PWM Output 1
8 [reserved] - Do not connect
9DTR / SLEEP_RQ / DI8 Input Pin Sleep Control Line or Digital Input 8
10 GND - Ground
11 AD4 / DIO4 Either Analog Input 4 or Digital I/O 4
12 CTS / DIO7 Either Clear-to-Send Flow Control or Digital I/O 7
13 ON / SLEEP Output Module Status Indicator
14 VREF Input Voltage Reference for A/D Inputs
15 Associate / AD5 / DIO5 Either Associated Indicator, Analog Input 5 or Digital I/O 5
16 RTS / DIO6 Either Request-to-Send Flow Control,or Digital I/O 6
17 AD3 / DIO3 Either Analog Input 3 or Digital I/O 3
18 AD2 / DIO2 Either Analog Input 2 or Digital I/O 2
19 AD1 / DIO1 Either Analog Input 1 or Digital I/O 1
20 AD0 / DIO0 Either Analog Input 0 or Digital I/O 0
Pin 1
Pin 10
Pin 1
Pin 10
Pin 20
Pin 11
Pin 20
Pin 11

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc. 8
Recommended Pin Connections
The only required pin connections are VCC, GND, DOUT and DIN. To support serial firmware
updates, VCC, GND, DOUT, DIN, RTS, and DTR should be connected.
All unused pins should be left disconnected. All inputs on the radio can be pulled high with internal
pull-up resistors using the PR software command. No specific treatment is needed for unused out-
puts.
Other pins may be connected to external circuitry for convenience of operation including the Asso-
ciate LED pin (pin 15). The Associate LED will flash differently depending on the state of the mod-
ule.
If analog sampling is desired, VRef (pin 14) should be attached to a voltage reference.
Board Layout
XBee modules are designed to be self sufficient and have minimal sensitivity to nearby processors,
crystals or other PCB components. As with all PCB designs, Power and Ground traces should be
thicker than signal traces and able to comfortably support the maximum current specifications. No
other special PCB design considerations are required for integrating XBee radios except in the
antenna section.
Antenna Performance
Antenna location is an important consideration for optimal performance. In general, antennas radi-
ate and receive best perpendicular to the direction they point. Thus a vertical antenna's radiation
pattern is strongest across the horizon. Metal objects near the antenna may impede the radiation
pattern. Metal objects between the transmitter and receiver can block the radiation path or reduce
the transmission distance, so antennas should be positioned away from them when possible. Some
objects that are often overlooked are metal poles, metal studs or beams in structures, concrete (it
is usually reinforced with metal rods), vehicles, elevators, ventilation ducts, refrigerators, micro-
wave ovens, batteries, and tall electrolytic capacitors. If the XBee is to be placed inside a metal
enclosure, an external antenna should be used.
XBee units with the Embedded PCB Antenna should not be placed inside a metal enclosure or have
any ground planes or metal objects above or below the antenna. For best results, place the XBee
at the edge of the host PCB on which it is mounted. Ensure that the ground, power and signal
planes are vacant immediately below the antenna section. Digi recommends allowing a “keepout”
area, which is shown in detail on the next page.

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
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XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
©2014DigiInternationalInc. 10
Electrical Characteristics of the XBee/XBee-PRO RF Module
Table1‐03. DCCharacteristics(VCC=2.8‐3.4VDC)
Symbol Characteristic Condition Min Typical Max Unit
VIL Input Low Voltage All Digital Inputs - - 0.35 * VCC V
VIH Input High Voltage All Digital Inputs 0.7 * VCC - - V
VOL Output Low Voltage IOL = 2 mA, VCC >= 2.7 V --0.5V
VOH Output High Voltage IOH = -2 mA, VCC >= 2.7 V VCC - 0.5 - - V
IIIN Input Leakage Current VIN = VCC or GND, all inputs, per pin - 0.025 1 µA
IIOZ High Impedance Leakage Current VIN = VCC or GND, all I/O High-Z, per pin - 0.025 1 µA
TX Transmit Current VCC = 3.3 V - 45
(XBee) 215,140
(PRO,
Int) -mA
RX Receive Current VCC = 3.3 V - 50
(XBee) 55 (PRO) -mA
PWR-DWN Power-down Current SM parameter = 1 - < 10 - µA
Table1‐04. ADCCharacteristics(Operating)
Symbol Characteristic Condition Min Typical Max Unit
VREFH VREF-Analog-to-Digitalconverter
reference range 2.08 - VDDAD* V
IREF VREF - Reference Supply Current Enabled - 200 - µA
Disabled or Sleep Mode - < 0.01 0.02 µA
VINDC Analog Input Voltage1
1. Maximumelectricaloperatingrange,notvalidconversionrange.
*VDDADisconnectedtoVCC.
VSSAD - 0.3 -VDDAD + 0.3 V
Table1‐05. ADCTiming/PerformanceCharacteristics1
1. AllACCURACYnumbersarebasedonprocessorandsystembeinginWAITstate(verylittleactivityandnoIOswitching)
andthatadequatelow‐passfilteringispresentonanaloginputpins(filterwith0.01μFto0.1μFcapacitorbetweenanalog
inputandVREFL).Failuretoobservetheseguidelinesmayresultinsystemormicrocontrollernoisecausingaccuracyerrors
whichwillvarybasedonboardlayoutandthetypeandmagnitudeoftheactivity.
Datatransmissionandreceptionduringdataconversionmaycausesomedegradationofthesespecifications,dependingon
thenumberandtimingofpackets.ItisadvisabletotesttheADCsinyourinstallationifbestaccuracyisrequired.
Symbol Characteristic Condition Min Typical Max Unit
RAS Source Impedance at Input2
2. RASistherealportionoftheimpedanceofthenetworkdrivingtheanaloginputpin.Valuesgreaterthanthisamountmay
notfullychargetheinputcircuitryoftheATDresultinginaccuracyerror.
--10 k
VAIN Analog Input Voltage3
3. AnaloginputmustbebetweenVREFLandVREFHforvalidconversion.ValuesgreaterthanVREFHwillconvertto$3FF.
VREFL VREFH V
RES Ideal Resolution (1 LSB)4
4. Theresolutionistheidealstepsizeor1LSB=(VREFH–VREFL)/1024
2.08V < VDDAD < 3.6V 2.031 - 3.516 mV
DNL Differential Non-linearity5
5. Differentialnon‐linearityisthedifferencebetweenthecurrentcodewidthandtheidealcodewidth(1LSB).Thecurrent
codewidthisthedifferenceinthetransitionvoltagestoandfromthecurrentcode.
- ±0.5 ±1.0 LSB
INL Integral Non-linearity6
6. Integralnon‐linearityisthedifferencebetweenthetransitionvoltagetothecurrentcodeandtheadjustedidealtransition
voltageforthecurrentcode.Theadjustedidealtransitionvoltageis(CurrentCode–1/2)*(1/((VREFH+EFS)–(VREFL+EZS))).
- ±0.5 ±1.0 LSB
EZS Zero-scale Error7
7. Zero‐scaleerroristhedifferencebetweenthetransitiontothefirstvalidcodeandtheidealtransitiontothatcode.The
Idealtransitionvoltagetoagivencodeis(Code–1/2)*(1/(VREFH–VREFL)).
- ±0.4 ±1.0 LSB
FFS Full-scale Error8
8. Full‐scaleerroristhedifferencebetweenthetransitiontothelastvalidcodeandtheidealtransitiontothatcode.Theideal
transitionvoltagetoagivencodeis(Code–1/2)*(1/(VREFH–VREFL)).
- ±0.4 ±1.0 LSB
EIL Input Leakage Error9
9. Inputleakageerroriserrorduetoinputleakageacrosstherealportionoftheimpedanceofthenetworkdrivingtheanalog
pin.Reducingtheimpedanceofthenetworkreducesthiserror.
- ±0.05 ±5.0 LSB
ETU Total Unadjusted Error10 - ±1.1 ±2.5 LSB

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx
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10.Totalunadjustederroristhedifferencebetweenthetransitionvoltagetothecurrentcodeandtheidealstraight‐linetrans‐
ferfunction.Thismeasureoferrorincludesinherentquantizationerror(1/2LSB)andcircuiterror(differential,integral,zero‐
scale,andfull‐scale)error.ThespecifiedvalueofETUassumeszeroEIL(noleakageorzerorealsourceimpedance).

©2014DigiInternationalInc. 12
2.XBee/XBee‐PRORFModuleOperation
Serial Communications of the XBee/XBee-PRO RF Module
The XBee®/XBee-PRO® RF Modules interface to a host device through a logic-level asynchronous
serial port. Through its serial port, the module can communicate with any logic and voltage com-
patible UART; or through a level translator to any serial device (For example: Through a Digi pro-
prietary RS-232 or USB interface board).
UART Data Flow
Devices that have a UART interface can connect directly to the pins of the RF module as shown in
the figure below.
Figure2‐01. SystemDataFlowDiagraminaUART‐interfacedenvironment
(Low‐assertedsignalsdistinguishedwithhorizontallineoversignalname.)
Serial Data
Data enters the module UART through the DI pin (pin 3) as an asynchronous serial signal. The sig-
nal should idle high when no data is being transmitted.
Each data byte consists of a start bit (low), 8 data bits (least significant bit first) and a stop bit
(high). The following figure illustrates the serial bit pattern of data passing through the module.
Figure2‐02. UARTdatapacket0x1F(decimalnumberʺ31ʺ)astransmittedthroughtheRFmodule
ExampleDataFormatis8‐N‐1(bits‐parity‐#ofstopbits)
Serial communications depend on the two UARTs (the microcontroller's and the RF module's) to be
configured with compatible settings (baud rate, parity, start bits, stop bits, data bits).
The UART baud rate and parity settings on the XBee module can be configured with the BD and NB
commands, respectively. See the command table in Chapter 3 for details.

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Transparent Operation
By default, XBee®/XBee-PRO® RF Modules operate in Transparent Mode. When operating in this
mode, the modules act as a serial line replacement - all UART data received through the DI pin is
queued up for RF transmission. When RF data is received, the data is sent out the DO pin.
Serial-to-RF Packetization
Data is buffered in the DI buffer until one of the following causes the data to be packetized and
transmitted:
If the module cannot immediately transmit (for instance, if it is already receiving RF data), the
serial data is stored in the DI Buffer. The data is packetized and sent at any RO timeout or when
100 bytes (maximum packet size) are received.
If the DI buffer becomes full, hardware or software flow control must be implemented in order to
prevent overflow (loss of data between the host and module).
API Operation
API (Application Programming Interface) Operation is an alternative to the default Transparent
Operation. The frame-based API extends the level to which a host application can interact with the
networking capabilities of the module.
When in API mode, all data entering and leaving the module is contained in frames that define
operations or events within the module.
Transmit Data Frames (received through the DI pin (pin 3)) include:
• RF Transmit Data Frame
• Command Frame (equivalent to AT commands)
Receive Data Frames (sent out the DO pin (pin 2)) include:
• RF-received data frame
• Command response
• Event notifications such as reset, associate, disassociate, etc.
The API provides alternative means of configuring modules and routing data at the host applica-
tion layer. A host application can send data frames to the module that contain address and payload
information instead of using command mode to modify addresses. The module will send data
frames to the application containing status packets; as well as source, RSSI and payload informa-
tion from received data packets.
The API operation option facilitates many operations such as the examples cited below:
To implement API operations, refer to API sections [p58].
1. No serial characters are received for the amount of time determined by the RO (Packetiza-
tion Timeout) parameter. If RO = 0, packetization begins when a character is received.
2. The maximum number of characters that will fit in an RF packet (100) is received.
3. The Command Mode Sequence (GT + CC + GT) is received. Any character buffered in the
DI buffer before the sequence is transmitted.
-> Transmitting data to multiple destinations without entering Command Mode
-> Receive success/failure status of each transmitted RF packet
-> Identify the source address of each received packet

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Flow Control
Figure2‐03. InternalDataFlowDiagram
DI (Data In) Buffer
When serial data enters the RF module through the DI pin (pin 3), the data is stored in the DI Buf-
fer until it can be processed.
Hardware Flow Control (CTS). When the DI buffer is 17 bytes away from being full; by default,
the module de-asserts CTS (high) to signal to the host device to stop sending data [refer to D7
(DIO7 Configuration) parameter]. CTS is re-asserted after the DI Buffer has 34 bytes of memory
available.
How to eliminate the need for flow control:
Case in which the DI Buffer may become full and possibly overflow:
Refer to the RO (Packetization Timeout), BD (Interface Data Rate) and D7 (DIO7 Configuration) com-
mand descriptions for more information.
DO (Data Out) Buffer
When RF data is received, the data enters the DO buffer and is sent out the serial port to a host
device. Once the DO Buffer reaches capacity, any additional incoming RF data is lost.
Hardware Flow Control (RTS). If RTS is enabled for flow control (D6 (DIO6 Configuration)
Parameter = 1), data will not be sent out the DO Buffer as long as RTS (pin 16) is de-asserted.
Two cases in which the DO Buffer may become full and possibly overflow:
Refer to the D6 (DIO6 Configuration) command description for more information.
1. Send messages that are smaller than the DI buffer size (202 bytes).
2. Interface at a lower baud rate [BD (Interface Data Rate) parameter] than the throughput
data rate.
If the module is receiving a continuous stream of RF data, any serial data that arrives on the DI
pin is placed in the DI Buffer. The data in the DI buffer will be transmitted over-the-air when the
module is no longer receiving RF data in the network.
1. If the RF data rate is set higher than the interface data rate of the module, the module will
receive data from the transmitting module faster than it can send the data to the host.
2. If the host does not allow the module to transmit data out from the DO buffer because of
being held off by hardware or software flow control.

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ADC and Digital I/O Line Support of the XBee/XBee-PRO RF Module
The XBee®/XBee-PRO® RF Modules support ADC (Analog-to-digital conversion) and digital I/O
line passing. The following pins support multiple functions:
To enable ADC and DIO pin functions:
I/O Data Format
I/O data begins with a header. The first byte of the header defines the number of samples forth-
coming. The last 2 bytes of the header (Channel Indicator) define which inputs are active. Each bit
represents either a DIO line or ADC channel.
Figure2‐04. Header
Sample data follows the header and the channel indicator frame is used to determine how to read
the sample data. If any of the DIO lines are enabled, the first 2 bytes are the DIO sample. The
ADC data follows. ADC channel data is represented as an unsigned 10-bit value right-justified on a
16- bit boundary.
Figure2‐05. SampleData
Table2‐01. Pinfunctionsandtheirassociatedpinnumbersandcommands
AD=Analog‐to‐DigitalConverter,DIO=DigitalInput/Output
Pinfunctionsnotapplicabletothissectionaredenotedwithin(parenthesis).
Pin Function Pin# AT Command
AD0 / DIO0 20 D0
AD1 / DIO1 19 D1
AD2 / DIO2 18 D2
AD3 / DIO3 / (COORD_SEL) 17 D3
AD4 / DIO4 11 D4
AD5 / DIO5 / (ASSOCIATE) 15 D5
DIO6 / (RTS) 16 D6
DIO7 / (CTS) 12 D7
DI8 / (DTR) / (Sleep_RQ) 9 D8
For ADC Support: Set ATDn = 2
For Digital Input support: Set ATDn = 3
For Digital Output Low support: Set ATDn = 4
For Digital Output High support: Set ATDn = 5
Header
Bit set to ‘1’ if channel is active
Bytes 2 - 3 (Channel Indicator)
na D8A0A1A2A3A4A5 D7 D0D1D2D3D4D5D6
Byte 1
Total number ofsamples
bit 15 bit 0
Sample Data
DIO LineDataisfirst (if enabled) ADCLineData
ADCn MSB ADCn LSB7 0123456X 8XXXXXX

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API Support
I/O data is sent out the UART using an API frame. All other data can be sent and received using
Transparent Operation [refer to p13] or API framing if API mode is enabled (AP > 0).
API Operations support two RX (Receive) frame identifiers for I/O data (set 16-bit address to
0xFFFE and the module will do 64-bit addressing):
• 0x82 for RX (Receive) Packet: 64-bit address I/O
• 0x83 for RX (Receive) Packet: 16-bit address I/O
The API command header is the same as shown in the “RX (Receive) Packet: 64-bit Address” and
“RX (Receive) Packet: 16-bit Address” API types [refer to p64]. RX data follows the format
described in the I/O Data Format section [p15].
Applicable Commands: AP (API Enable)
Sleep Support
Automatic wakeup sampling can be suppressed by setting SO bit 1.When an RF module wakes, it
will always do a sample based on any active ADC or DIO lines. This allows sampling based on the
sleep cycle whether it be Cyclic Sleep (SM parameter = 4 or 5) or Pin Sleep (SM = 1 or 2). To
gather more samples when awake, set the IR (Sample Rate) parameter.
For Cyclic Sleep modes: If the IR parameter is set, the module will stay awake until the IT (Sam-
ples before TX) parameter is met. The module will stay awake for ST (Time before Sleep) time.
Applicable Commands: IR (Sample Rate), IT (Samples before TX), SM (Sleep Mode), IC (DIO
Change Detect), SO (Sleep Options)
DIO Pin Change Detect
When “DIO Change Detect” is enabled (using the IC command), DIO lines 0-7 are monitored.
When a change is detected on a DIO line, the following will occur:
Note: Change detect will not affect Pin Sleep wake-up. The D8 pin (DTR/Sleep_RQ/DI8) is the only
line that will wake a module from Pin Sleep. If not all samples are collected, the module will still
enter Sleep Mode after a change detect packet is sent.
Applicable Commands: IC (DIO Change Detect), IT (Samples before TX)
NOTE: Change detect is only supported when the Dx (DIOx Configuration) parameter equals 3,4 or 5.
Sample Rate (Interval)
The Sample Rate (Interval) feature allows enabled ADC and DIO pins to be read periodically on
modules that are not configured to operate in Sleep Mode. When one of the Sleep Modes is
enabled and the IR (Sample Rate) parameter is set, the module will stay awake until IT (Samples
before TX) samples have been collected.
Once a particular pin is enabled, the appropriate sample rate must be chosen. The maximum sam-
ple rate that can be achieved while using one A/D line is 1 sample/ms or 1 KHz (Note that the
modem will not be able to keep up with transmission when IR & IT are equal to “1” and that con-
figuring the modem to sample at rates greater than once every 20ms is not recommended).
Applicable Commands: IR (Sample Rate), IT (Samples before TX), SM (Sleep Mode)
1. An RF packet is sent with the updated DIO pin levels. This packet will not contain any ADC
samples.
2. Any queued samples are transmitted before the change detect data. This may result in
receiving a packet with less than IT (Samples before TX) samples.

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I/O Line Passing
Virtual wires can be set up between XBee®/XBee-PRO® Modules. When an RF data packet is
received that contains I/O data, the receiving module can be setup to update any enabled outputs
(PWM and DIO) based on the data it receives.
Note that I/O lines are mapped in pairs. For example: AD0 can only update PWM0 and DI5 can
only update DO5. The default setup is for outputs not to be updated, which results in the I/O data
being sent out the UART (refer to the IU (Enable I/O Output) command). To enable the outputs to
be updated, the IA (I/O Input Address) parameter must be setup with the address of the module
that has the appropriate inputs enabled. This effectively binds the outputs to a particular module’s
input. This does not affect the ability of the module to receive I/O line data from other modules -
only its ability to update enabled outputs. The IA parameter can also be setup to accept I/O data
for output changes from any module by setting the IA parameter to 0xFFFF.
When outputs are changed from their non-active state, the module can be setup to return the out-
put level to it non-active state. The timers are set using the Tn (Dn Output Timer) and PT (PWM
Output Timeout) commands. The timers are reset every time a valid I/O packet (passed IA check)
is received. The IC (Change Detect) and IR (Sample Rate) parameters can be setup to keep the
output set to their active output if the system needs more time than the timers can handle.
Note: DI8 cannot be used for I/O line passing.
Applicable Commands: IA (I/O Input Address), Tn (Dn Output Timeout), P0 (PWM0 Configura-
tion), P1 (PWM1 Configuration), M0 (PWM0 Output Level), M1 (PWM1 Output Level), PT (PWM
Output Timeout), RP (RSSSI PWM Timer)
Configuration Example
As an example for a simple A/D link, a pair of RF modules could be set as follows:
These settings configure the remote module to sample AD0 and AD1 once each every 20 ms. It
then buffers 5 samples each before sending them back to the base module. The base should then
receive a 32-Byte transmission (20 Bytes data and 12 Bytes framing) every 100 ms.
Remote Configuration
DL = 0x1234
MY = 0x5678
D0 = 2
D1 = 2
IR = 0x14
IT = 5
Base Configuration
DL = 0x5678
MY = 0x1234
P0 = 2
P1 = 2
IU = 1
IA = 0x5678 (or 0xFFFF)

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XBee®/XBee-PRO®Networks
The following terms will be used to explicate the network operations:
Peer-to-Peer
By default, XBee®/XBee-PRO RF Modules are configured to operate within a Peer-to-Peer network
topology and therefore are not dependent upon Master/Slave relationships. NonBeacon systems
operate within a Peer-to-Peer network topology and therefore are not dependent upon Master/
Slave relationships. This means that modules remain synchronized without use of master/server
configurations and each module in the network shares both roles of master and slave. Digi's peer-
to-peer architecture features fast synchronization times and fast cold start times. This default con-
figuration accommodates a wide range of RF data applications.
Figure2‐06. Peer‐to‐PeerArchitecture
A peer-to-peer network can be established by
configuring each module to operate as an End Device (CE = 0), disabling End Device Association
on all modules (A1 = 0) and setting ID and CH parameters to be identical across the network.
NonBeacon (w/ Coordinator)
A device is configured as a Coordinator by setting the CE (Coordinator Enable) parameter to “1”.
Coordinator power-up is governed by the A2 (Coordinator Association) parameter.
In a Coordinator system, the Coordinator can be configured to use direct or indirect transmissions.
If the SP (Cyclic Sleep Period) parameter is set to “0”, the Coordinator will send data immediately.
Otherwise, the SP parameter determines the length of time the Coordinator will retain the data
before discarding it. Generally, SP (Cyclic Sleep Period) and ST (Time before Sleep) parameters
should be set to match the SP and ST settings of the End Devices.
Table 2‐02. Termsanddefinitions
Term Definition
PAN PersonalAreaNetwork-AdatacommunicationnetworkthatincludesoneormoreEndDevicesand
optionally a Coordinator.
Coordinator A Full-function device (FFD) that provides network synchronization by polling nodes [NonBeacon
(w/ Coordinator) networks only]
End Device When in the same network as a Coordinator - RF modules that rely on a Coordinator for
synchronization and can be put into states of sleep for low-power applications.
Association The establishment of membership between End Devices and a Coordinator. Association is only
applicable in NonBeacon (w/Coordinator) networks.

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Association
Association is the establishment of membership between End Devices and a Coordinator. The
establishment of membership is useful in scenarios that require a central unit (Coordinator) to
relay messages to or gather data from several remote units (End Devices), assign channels or
assign PAN IDs.
An RF data network that consists of one Coordinator and one or more End Devices forms a PAN
(Personal Area Network). Each device in a PAN has a PAN Identifier [ID (PAN ID) parameter]. PAN
IDs must be unique to prevent miscommunication between PANs. The Coordinator PAN ID is set
using the ID (PAN ID) and A2 (Coordinator Association) commands.
An End Device can associate to a Coordinator without knowing the address, PAN ID or channel of
the Coordinator. The A1 (End Device Association) parameter bit fields determine the flexibility of
an End Device during association. The A1 parameter can be used for an End Device to dynamically
set its destination address, PAN ID and/or channel.
Coordinator / End Device Setup and Operation
To configure a module to operate as a Coordinator, set the CE (Coordinator Enable) parameter to
‘1’. Set the CE parameter of End Devices to ‘0’ (default). Coordinator and End Devices should con-
tain matching firmware versions.
NonBeacon (w/ Coordinator) Systems
The Coordinator can be configured to use direct or indirect transmissions. If the SP (Cyclic Sleep
Period) parameter is set to ‘0’, the Coordinator will send data immediately. Otherwise, the SP
parameter determines the length of time the Coordinator will retain the data before discarding it.
Generally, SP (Cyclic Sleep Period) and ST (Time before Sleep) parameters should be set to match
the SP and ST settings of the End Devices.
Coordinator Start-up
Coordinator power-up is governed by the A2 (Coordinator Association) command. On power-up,
the Coordinator undergoes the following sequence of events:
1. Check A2 parameter- Reassign_PANID Flag
Set (bit 0 = 1) - The Coordinator issues an Active Scan. The Active Scan selects one channel
and transmits a request to the broadcast address (0xFFFF) and broadcast PAN ID (0xFFFF). It
then listens on that channel for beacons from any Coordinator operating on that channel. The
listen time on each channel is determined by the SD (Scan Duration) parameter value.
Once the time expires on that channel, the Active Scan selects another channel and again
transmits the BeaconRequest as before. This process continues until all channels have been
scanned, or until 5 PANs have been discovered. When the Active Scan is complete, the results
include a list of PAN IDs and Channels that are being used by other PANs. This list is used to
assign an unique PAN ID to the new Coordinator. The ID parameter will be retained if it is not
found in the Active Scan results. Otherwise, the ID (PAN ID) parameter setting will be updated
to a PAN ID that was not detected.
Not Set (bit 0 = 0) - The Coordinator retains its ID setting. No Active Scan is performed.
For example: If the PAN ID of a Coordinator is known, but the operating channel is not; the A1
command on the End Device should be set to enable the ‘Auto_Associate’ and
‘Reassign_Channel’ bits. Additionally, the ID parameter should be set to match the PAN ID of
the associated Coordinator.

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2. Check A2 parameter - Reassign_Channel Flag (bit 1)
Set (bit 1 = 1) - The Coordinator issues an Energy Scan. The Energy Scan selects one channel
and scans for energy on that channel. The duration of the scan is specified by the SD (Scan
Duration) parameter. Once the scan is completed on a channel, the Energy Scan selects the
next channel and begins a new scan on that channel. This process continues until all channels
have been scanned.
When the Energy Scan is complete, the results include the maximal energy values detected on
each channel. This list is used to determine a channel where the least energy was detected. If
an Active Scan was performed (Reassign_PANID Flag set), the channels used by the detected
PANs are eliminated as possible channels. Thus, the results of the Energy Scan and the Active
Scan (if performed) are used to find the best channel (channel with the least energy that is not
used by any detected PAN). Once the best channel has been selected, the CH (Channel) param-
eter value is updated to that channel.
Not Set (bit 1 = 0) - The Coordinator retains its CH setting. An Energy Scan is not performed.
3. Start Coordinator
The Coordinator starts on the specified channel (CH parameter) and PAN ID (ID parameter).
Note, these may be selected in steps 1 and/or 2 above. The Coordinator will only allow End
Devices to associate to it if the A2 parameter “AllowAssociation” flag is set. Once the Coordina-
tor has successfully started, the Associate LED will blink 1 time per second. (The LED is solid if
the Coordinator has not started.)
4. Coordinator Modifications
Once a Coordinator has started: 
Modifying the A2 (Reassign_Channel or Reassign_PANID bits), ID, CH or MY parameters will
cause the Coordinator’s MAC to reset (The Coordinator RF module (including volatile RAM) is
not reset). Changing the A2 AllowAssociation bit will not reset the Coordinator’s MAC. In a non-
beaconing system, End Devices that associated to the Coordinator prior to a MAC reset will have
knowledge of the new settings on the Coordinator. Thus, if the Coordinator were to change its
ID, CH or MY settings, the End Devices would no longer be able to communicate with the non-
beacon Coordinator. Once a Coordinator has started, the ID, CH, MY or A2 (Reassign_Channel
or Reassign_PANID bits) should not be changed.
End Device Start-up
End Device power-up is governed by the A1 (End Device Association) command. On power-up, the
End Device undergoes the following sequence of events:
1. Check A1 parameter - AutoAssociate Bit
Set (bit 2 = 1) - End Device will attempt to associate to a Coordinator. (refer to steps 2-3).
Not Set (bit 2 = 0) - End Device will not attempt to associate to a Coordinator. The End Device
will operate as specified by its ID, CH and MY parameters. Association is considered complete
and the Associate LED will blink quickly (5 times per second). When the AutoAssociate bit is not
set, the remaining steps (2-3) do not apply.
2. Discover Coordinator (if Auto-Associate Bit Set)
The End Device issues an Active Scan. The Active Scan selects one channel and transmits a
BeaconRequest command to the broadcast address (0xFFFF) and broadcast PAN ID (0xFFFF). It
then listens on that channel for beacons from any Coordinator operating on that channel. The
listen time on each channel is determined by the SD parameter.
Once the time expires on that channel, the Active Scan selects another channel and again
transmits the BeaconRequest command as before. This process continues until all channels
have been scanned, or until 5 PANs have been discovered. When the Active Scan is complete,
the results include a list of PAN IDs and Channels that are being used by detected PANs.