Digi S2CTH XBee ZB module User Manual

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XBee ÂŽ /XBee-PRO ÂŽ ZB RF Modules
ZigBee RF Modules by Digi International
Models: XBEE S2C, PRO S2C, S2CTH
Hardware: S2C
Firmware: 401x, 402x, 403x, 404x, 405x
Digi International Inc.
11001 Bren Road East
Minnetonka, MN 55343
877 912-3444 or 952 912-3444
http://www.digi.com
90002002_M
5/7/2014
XBee®/XBee‐PRO® ZB RF Modules
Š 2014 Digi International Inc. All rights reserved.
ZigBeeÂŽ is a registered trademark of the ZigBee alliance. XBee-PROÂŽ XBeeÂŽ Digi, Digi International, and the Digi logo are
trademarks or registered trademarks of Digi International Inc. in the United States and other countries worldwide. All other
trademarks mentioned in this document are the property of their respective owners.
Information in this document is subject to change without notice and does not represent a commitment on the part of Digi
International.
Digi provides this document “as is,” without warranty of any kind, expressed or implied, including, but not limited to, the
implied warranties of fitness or merchantability for a particular purpose. Digi may make improvements and/or changes in this
manual or in the product(s) and/or the program(s) described in this manual at any time.
This product could include technical inaccuracies or typographical errors. Changes are periodically made to the information
herein; these changes may be incorporated in new editions of the publication.
Technical Support:
Phone:
(866) 765-9885 toll-free U.S.A. & Canada
(801) 765-9885 Worldwide
8:00 am - 5:00 pm [U.S. Mountain Time]
Š 2014 Digi International Inc.
Live Chat:
www.digi.com
Online Support:
www.digi.com/support/eservice/login.jsp
Email:
rf-experts@digi.com
XBee®/XBee‐PRO® ZB RF Modules
Contents
Overview of the XBee ZigBee RF Module 6
Worldwide Acceptance 6
What’s New in 40xx Firmware 6
Specifications of the XBee ZigBee RF Module 7
Serial Communications Specifications of the XBee
ZigBee RF Module 8
UART 8
SPI 8
GPIO Specifications 8
ZigBee Stack Layers 34
XigBee Networking Concepts 34
Device Types 34
PAN ID 36
Operating Channel 36
ZigBee Application Layers: In Depth 36
Application Support Sublayer (APS) 36
Application Profiles 36
ZigBee Coordinator Operation 38
Hardware Specifications for Programmable Variant 9
Forming a Network 38
Mechanical Drawings of the XBee ZigBee RF Module
10
Channel Selection 38
Pin Signals for the XBee ZigBee Surface Mount Module 11
Security Policy 38
Pin Signals for the XBee ZigBee Through-hole Module
12
XBee ZigBee Coordinator Startup 38
EM357 Pin Mappings 13
Design Notes for the XBee ZigBee RF Module 13
Power Supply Design 13
Recommended Pin Connections 13
Board Layout 14
Module Operation for Programmable Variant 17
XBee Programmable Bootloader 19
Overview 19
Bootloader Software Specifics 19
Bootloader Menu Commands 23
Firmware Updates 24
Output File Configuration 25
XBee ZigBee RF Module Operation 26
XBee ZigBee Serial Communications 26
PAN ID Selection 38
Persistent Data 38
Permit Joining 39
Resetting the Coordinator 40
Leaving a Network 40
Replacing a Coordinator (Security Disabled Only) 40
Example: Starting a Coordinator 41
Example: Replacing a Coordinator (Security Disabled) 41
ZigBee Router Operation 41
Discovering ZigBee Networks 41
Joining a Network 42
Authentication 42
Persistent Data 42
XBee ZB Router Joining 42
Permit Joining 43
Joining Always Enabled 43
Joining Temporarily Enabled 43
UART Data Flow 26
Router Network Connectivity 44
XBee ZigBee SPI Communications 26
Leaving a Network 45
XBee ZigBee Serial Buffers 27
Network Locator Option 45
UART Flow Control 28
Resetting the Router 46
XBee ZigBee Break Control 29
Example: Joining a Network 46
Serial Interface Protocols 29
XBee ZigBee Modes of Operation 31
End Device Operation 46
Discovering ZigBee Networks 46
Idle Mode 31
Joining a Network 47
Transmit Mode 31
Parent Child Relationship 47
Receive Mode 32
End Device Capacity 47
Command Mode 32
Authentication 47
Sleep Mode 33
XBee ZigBee Networks 34
Introduction to ZigBee 34
Š 2014 Digi International Inc.
Persistent Data 47
Orphan Scans 47
XBee ZigBee End Device Joining 48
XBee®/XBee‐PRO® ZB RF Modules
Contents
Parent Connectivity 48
Frame Counter 72
Resetting the End Device 49
Message Integrity Code 72
Leaving a Network 49
Network Layer Encryption and Decryption 72
Example: Joining a Network 49
Network Key Updates 72
ZigBee Channel Scanning 49
APS Layer Security 72
Managing Multiple ZigBee Networks 50
Message integrity Code 73
PAN ID Filtering 50
APS Link Keys 73
Pre-configured Security Keys 50
APS Layer Encryption and Decryption 73
Permit Joining 50
Network and APS Layer Encryption 73
Application Messaging 50
Trust Center 74
Transmission, Addressing, and Routing 51
Addressing 51
64-bit Device Addresses 51
16-bit Device Addresses 51
Application Layer Addressing 51
Data Transmission 51
Broadcast Transmissions 52
Unicast Transmissions 52
Binding Transmissions 54
Multicast Transmissions 54
Fragmentation 54
Data Transmission Examples 55
RF Packet Routing 57
Link Status Transmission 57
AODV Mesh Routing 58
Many-to-One Routing 60
Source Routing 61
Encrypted Transmissions 64
Maximum RF Payload Size 64
Throughput 64
Latency Timing Specifications 65
ZDO Transmissions 65
ZigBee Device Objects (ZDO) 65
Sending a ZDO Command 66
Receiving ZDO Commands and Responses 66
Transmission Timeouts 67
Unicast Timeout 68
Forming and Joining a Secure Network 74
Implementing Security on the XBee 74
Enabling Security 75
Setting the Network Security Key 75
Setting the APS Trust Center Link Key 75
Enabling APS Encryption 75
Using a Trust Center 75
XBee Security Examples 76
Example 1: Forming a network with security (pre-configured link keys) 76
Example 2: Forming a network with security (obtaining keys during joining) 76
Network Commissioning and Diagnostics 78
Device Configuration 78
Device Placement 78
Link Testing 78
RSSI Indicators 79
Device Discovery 79
Network Discovery 79
ZDO Discovery 79
Joining Announce 79
Commissioning Pushbutton and Associate LED 79
Commissioning Pushbutton 80
Associate LED 81
Binding 82
Group Table API 84
Managing End Devices 94
Extended Timeout 68
End Device Operation 94
Transmission Examples 69
Parent Operation 94
XBee ZigBee Security 71
Security Modes 71
ZigBee Security Model 71
Network Layer Security 71
Š 2014 Digi International Inc.
End Device Poll Timeouts 95
Packet Buffer Usage 95
Non-Parent Device Operation 95
XBee End Device Configuration 96
Pin Sleep 96
XBee®/XBee‐PRO® ZB RF Modules
Contents
Cyclic Sleep 98
ZigBee Transmit Status 123
Transmitting RF Data 101
ZigBee Receive Packet 124
Receiving RF Data 101
ZigBee Explicit Rx Indicator 125
I/O Sampling 102
ZigBee IO Data Sample Rx Indicator 126
Waking End Devices with the Commissioning Pushbutton 102
XBee Sensor Read Indicator 127
Parent Verification 102
Remote Command Response 130
Rejoining 102
Over-the-Air Firmware Update Status 131
XBee Router/Coordinator Configuration 102
RF Packet Buffering Timeout 103
Child Poll Timeout 103
Transmission Timeout 103
Putting It All Together 104
Node Identification Indicator 129
Route Record Indicator 132
Many-to-One Route Request Indicator 133
Sending ZigBee Device Objects (ZDO) Commands
with the API 134
Short Sleep Periods 104
Sending ZigBee Cluster Library (ZCL) Commands
with the API 136
Extended Sleep Periods 104
Sending Public Profile Commands with the API 138
Sleep Examples 104
XBee Analog and Digital I/O Lines 106
XBee ZB Through Hole RF Module 106
XBee Command Reference Tables 141
XBee ZigBee Module Support 152
X-CTU Configuration Tool 152
I/O Configuration 107
Customizing XBee ZB Firmware 152
I/O Sampling 108
Queried Sampling 109
Design Considerations for Digi Drop-In Networking
152
Periodic I/O Sampling 109
XBee Bootloader 152
Change Detection Sampling 109
Programming XBee Modules 153
RSSI PWM 110
I/O Examples 110
PWM1 110
XBee ZigBee API Operation 111
API Frame Specifications 111
API Examples 113
API Serial Port Exchanges 114
AT Commands 114
Transmitting and Receiving RF Data 114
Remote AT Commands 114
Source Routing 115
Serial Firmware Updates 153
Invoke XBee Bootloader 153
Send Firmware Image 153
Writing Custom Firmware 153
Regulatory Compliance 153
Enabling GPIO 1 and 2 154
Detecting XBee vs. XBee-PRO 154
Special Instructions For Using the JTAG Interface 154
Appendix A: Agency Certifications 156
Appendix B:Migrating from XBee ZB to XBee ZB RF
Modules 162
Supporting the API 115
Appendix C:Manufacturing Information 165
API Frames 115
Appendix D:Warranty Information 168
AT Command 115
Appendix E:Definitions 169
AT Command - Queue Parameter Value 116
ZigBee Transmit Request 116
Explicit Addressing ZigBee Command Frame 118
Remote AT Command Request 120
Create Source Route 121
AT Command Response 122
Modem Status 122
Š 2014 Digi International Inc.
1. Overview of the XBee ZigBee RF Module
This manual describes the operation of the XBee/XBee-PRO ZB RF module, which
consists of ZigBee firmware loaded onto XBee S2C and PRO S2C hardware.
XBeeÂŽ and XBee-PROÂŽ ZB embedded RF modules provide wireless connectivity
to end-point devices in ZigBee mesh networks. Utilizing the ZigBee PRO Feature
Set, these modules are interoperable with other ZigBee devices, including
devices from other vendors. With the XBee, users can have their ZigBee network
up-and-running in a matter of minutes without configuration or addtional development.
The XBee/XBee-PRO ZB modules are compatible with other devices that use XBee “ZB” technology. These include ConnectPortX gateways, XBee and XBee-PRO Adapters, Wall Routers, XBee Sensors, and other products with the “ZB” name.
Worldwide Acceptance
FCC Approval (USA) Refer to Appendix A for FCC Requirements. Systems that contain XBee/XBeePRO ZB RF Modules inherit Digi Certifications.
ISM (Industrial, Scientific & Medical) 2.4 GHz frequency band
Manufactured under ISO 9001:2000 registered standards
XBee/XBee-PRO ZB RF Modules are optimized for use in US, Canada, Europe, Australia, and Japan (contact
Digi for complete list of agency approvals).
What’s New in 40xx Firmware
• An alternative serial port is available using SPI slave mode operation.
• Six software images (Coordinator AT, Coordinator API, Router AT, Router API, End Device AT,
and End Device API) are combined into a single software.
• Fragmentation is now available in both API mode and transparent mode.
• P3 (DOUT), P4 (DIN), D8 (SleepRq), and D9 (On-Sleep) are now available for I/O sampling.
• Both pull-up and pull-down resistors can now be applied to pins configured for inputs.
• 401D - ATVL command added for long version information
• 401E - ATDO command added for configuring device options
• 4020 - ATAS command added for Active Scan
• 4021 - Self addressed Tx Status messages return a status code of 0x23
• ATDO has HIGH_RAM_CONCENTRATOR and NO_ACK_IO_SAMPLING options added.
• 4040 - Binding and Multicasting transmissions are supported.
• AT&X command added to clear binding and group tables.
• Added Tx options 0x04 (indirect addressing) and 0x08 (multicast addressing).
• A 5 second break will reset the XBee. Then it will boot with default baud settings into command mode
• BD range increased from 0-7 to 0-0x0A, and nonstandard baud rates are permitted, but not
guaranteed.
• NI, DN, ND string parameters support upper and lower case
• TxOption 0x01 disables retries and route repair. RxOption 0x01 indicates the transmitter disabled retries.
• 4050 - FR returns 0x00 modem status code instead of 0x01.
• S2C TH and S2C TH PRO supported.
• DC10 - verbose joining mode option.
• Self addressed fragmentable messages now return the self-addressed Tx Status code (0x23)
instead of simply success (0x00).
Š 2014 Digi International Inc.
XBee®/XBee‐PRO® ZB RF Modules
Specifications of the XBee ZigBee RF Module
Specifications of the XBee®/XBee‐PRO® ZB RF Module
Specification
XBee (Surface Mount)
XBee-PRO (Surface Mount)
XBee (Through-hole)
Indoor/Urban Range
Up to 200 ft. (60 m)
Up to 300 ft. (90 m)
Up to 200 ft. (60 m)
Outdoor RF line-of-sight
Range
Up to 4000 ft. (1200 m)
Up to 2 miles (3200 m)
Up to 4000 ft. (1200 m)
Transmit Power Output
(maximum)
6.3mW (+8dBm), Boost mode
3.1mW (+5dBm), Normal mode
Channel 26 max power is +3dBm
63mW (+18 dBm)
6.3mW (+8dBm), Boost mode
3.1mW (+5dBm), Normal mode
Channel 26 max power is +3dBm
FCC/IC Test Transmit
Power Output range
-26 to +8 dBm
0 to +18 dBm
-26 to +8 dBm
Performance
RF Data Rate
Receiver Sensitivity
250,000 bps
-102 dBm, Boost mode
-100 dBm, Normal mode
-102 dBm, Boost mode
-100 dBm, Normal mode
-101 dBm
Power Requirements
Adjustable Power
Yes
Supply Voltage
2.1 - 3.6 V
2.7 - 3.6 V
2.2 - 3.6 V for Programmable Version
2.1 - 3.6 V
2.2 - 3.6 V for Programmable Version
Operating Current
(Transmit))
45mA (+8 dBm, Boost mode)
33mA (+5 dBm, Normal mode)
100mA @ +3.3 V, +18 dBm
45mA (+8 dBm, Boost mode)
33mA (+5 dBm, Normal mode)
Operating Current
(Receive)
31mA ( Boost mode)
28mA (Normal mode)
31mA
31mA ( Boost mode)
28mA (Normal mode)
< 1 A @ 25oC
Power-down Current
General
Operating Frequency
Band
ISM 2.4 - 2.5 GHz
Dimensions
0.866” x 1.33” x 0.120” (2.199cm x 3.4cm x 0.305cm)
Operating Temperature
0.960 x 1.087 in (2.438 x 2.761 cm)
-40 to 85Âş C (industrial)
Antenna Options
RF Pad, PCB Antenna, or U.FL Connector
PCB Antenna, U.FL Connector,
RPSMA Connector, or Integrated
Wire
Networking & Security
Supported Network
Topologies
Number of Channels
Point-to-point, Point-to-multipoint, Peer-to-peer, and Mesh
16 Direct Sequence Channels
Interface Immunity
Channels
15 Direct Sequence Channels
16 Direct Sequence Channels
DSSS (Direct Sequence Spread Spectrum)
11 to 26
Addressing Options
11 to 25
11 to 26
PAN ID and Addresses, Cluster IDs and Endpoints (optional)
Interface Options
UART
1 Mbps maximum (burst)
SPI
5 Mbps maximum (burst)
Agency Approvals
United States (FCC Part
15.247)
FCC ID: MCQ-XBS2C
FCC ID: MCQ-XBPS2C
FCC ID: MCQ-S2CTH
Industry Canada (IC)
IC: 1846A-XBS2C
IC: 1846A-XBPS2C
IC: 1846A-S2CTH
Europe (CE)
ETSI
Š 2014 Digi International Inc.
ETSI
XBee®/XBee‐PRO® ZB RF Modules
Specifications of the XBee®/XBee‐PRO® ZB RF Module
Specification
XBee (Surface Mount)
XBee-PRO (Surface Mount)
Australia
XBee (Through-hole)
C-Tick
Japan
R201WW10215369
RoHS
Pending
Compliant
Serial Communications Specifications of the XBee ZigBee RF Module
XBee RF modules support both UART (Universal Asynchronous Receiver / Transmitter) and SPI (Serial
Peripheral Interface) serial connections.
UART
The SC1 (Serial Communication Port 1) of the Ember 357 is connected to the UART port.
UART Pin Assignments
Specifications
Module Pin Number
UART Pins
XBee (Surface Mount)
XBee (Through-hole)
DOUT
DIN / CONFIG
CTS / DIO7
25
12
RTS / DIO6
29
16
More information on UART operation is found in the UART section in Chapter 2.
SPI
The SC2 (Serial Communication Port 2) of the Ember 357 is connected to the SPI port.
SPI Pin Assignments
Specifications
SPI Pins
Module Pin Number
XBee (Surface Mount)
XBee (Through-hole)
SPI_SCLK / DIO18
14
18
SPI_SSEL / DIO17
15
17
SPI_MOSI / DIO16
16
11
SPI_MISO / DIO15
17
For more information on SPI operation, see the SPI section in Chapter 2.
GPIO Specifications
XBee RF modules have 15 GPIO (General Purpose Input / Output) ports available. The exact list will depend on
the module configuration, as some GPIO pads are used for purposes such as serial communication.
See GPIO section for more information on configuring and using GPIO ports.
Electrical Specifications for GPIO Pads
GPIO Electrical Specification
Value
Voltage - Supply
2.1 - 3.6 V
Low Schmitt switching threshold
0.42 - 0.5 x VCC
High Schmitt switching threshold
0.62 - 0.8 x VCC
Input current for logic 0
-0.5 A
Input current for logic 1
0.5 A
Input pull-up resistor value
29 k
Input pull-down resistor value
29 k
Output voltage for logic 0
0.18 x VCC (maximum)
Output voltage for logic 1
0.82 x VCC (minimum)
Š 2014 Digi International Inc.
XBee®/XBee‐PRO® ZB RF Modules
Electrical Specifications for GPIO Pads
GPIO Electrical Specification
Value
Output source current for pad numbers 3, 4, 5, 10, 12, 14, 15,
16, 17, 25, 26, 28, 29, 30, and 32 on the SMT modules
4 mA
Output source current for pad numbers 3, 4, 5, 10, 12, 14, 16,
17, 26, 28, 29, 30, and 33 on the SMT modules
4 mA
Output source current for pad numbers 2, 3, 4, 9, 12, 13, 15, 16,
17, and19 on the TH modules
4 mA
Output source current for pad numbers 7, 8, 24, 31, and 33 on
the SMT modules
8 mA
Output sink current for pad numbers 7, 8, 24, 31, and 33 on the
SMT modules
8 mA
Output sink current for pad numbers 6, 7, 11, 18, and 20 on the
TH modules
8 mA
Total output current (for GPIO pads)
40 mA
Hardware Specifications for Programmable Variant
If the module has the programmable secondary processor, add the following table values to the specifications
listed on page 7. For example, if the secondary processor is running at 20 MHz and the primary processor is in
recieve mode then the new current value will be Itotal = Ir2 + Irx = 14 mA + 9 mA = 23 mA, where Ir2 is the
runtime current of the secondary processor and Irx is the recieve current of the primary.
Specifications of the programmable secondary processor
Š 2014 Digi International Inc.
Optional Secondary Processor Specification
These numbers add to specifications
(Add to RX, TX, and sleep currents depending on
mode of operation)
Runtime current for 32k running at 20MHz
+14mA
Runtime current for 32k running at 1MHz
+1mA
Sleep current
+0.5A typical
For additional specifications see Freescale Datasheet and
Manual
MC9SO8QE32
Minimum Reset low pulse time for EM357
+26S
VREF Range
1.8VDC to VCC
XBee®/XBee‐PRO® ZB RF Modules
Mechanical Drawings of the XBee ZigBee RF Module
Mechanical drawings of the XBee®/XBee‐PRO® ZB RF Modules (antenna options not shown). All dimensions are in inches.
7239,(:
6,'(9,(:
%277209,(:
3,1



3,1

Š 2014 Digi International Inc.


10
XBee®/XBee‐PRO® ZB RF Modules
Pin Signals for the XBee ZigBee Surface Mount Module
Pin Assignments for XBee Surface Mount Modules
(Low‐asserted signals are distinguished with a horizontal line above signal name.)
Pin #
Name
Direction
Default State
GND
Description
Ground
VCC
Power Supply
DOUT / DIO13
Both
Output
UART Data Out / GPIO
DIN / CONFIG / DIO14
Both
Input
UART Data In / GPIO
DIO12
Both
GPIO
RESET
Input
Module Reset
RSSI PWM / DIO10
Both
Output
RX Signal Strength Indicator / GPIO
PWM1 / DIO11
Both
Disabled
Pulse Width Modulator / GPIO
[reserved]
Disabled
Do Not Connect
10
DTR / SLEEP_RQ / DIO8
Both
Input
Pin Sleep Control Line / GPIO
11
GND
Ground
12
SPI_ATTN / BOOTMODE / DIO19
Output
Output
Serial Peripheral Interface Attention
Do not tie low on reset
13
GND
Ground
14
SPI_CLK / DIO18
Input
Input
Serial Peripheral Interface Clock / GPIO
15
SPI_SSEL / DIO 17
Input
Input
Serial Peripheral Interface not Select / GPIO
16
SPI_MOSI / DIO16
Input
Input
Serial Peripheral Interface Data In / GPIO
17
SPI_MISO / DIO15
Output
Output
Serial Peripheral Interface Data Out / GPIO
18
[reserved]*
Disabled
Do Not Connect
19
[reserved]*
Disabled
Do Not Connect
20
[reserved]*
Disabled
Do Not Connect
21
[reserved]*
Disabled
Do Not Connect
22
GND
Ground
23
[reserved]
Disabled
Do Not Connect
24
DIO4
Both
Disabled
GPIO
25
CTS / DIO7
Both
Output
Clear to Send Flow Control / GPIO
26
ON / SLEEP / DIO9
Both
Output
Module Status Indicator / GPIO
27
VREF
Input
Not used for EM357. Used for programmable
secondary processor. For compatibility with other
XBee modules, we recommend connecting this pin
to the voltage reference if Analog Sampling is
desired. Otherwise, connect to GND.
28
ASSOCIATE / DIO5
Both
Output
Associate Indicator / GPIO
29
RTS / DIO6
Both
Input
Request to Send Flow Control / GPIO
30
AD3 / DIO3
Both
Disabled
Analog Input / GPIO
31
AD2 / DIO2
Both
Disabled
Analog Input / GPIO
32
AD1 / DIO1
Both
Disabled
Analog Input / GPIO
33
AD0 / DIO0
Both
Input
Analog Input / GPIO
34
[reserved]
Disabled
Do Not Connect
35
GND
Ground
36
RF
Both
RF IO for RF Pad Variant
37
[reserved]
Disabled
Do Not Connect
• Signal Direction is specified with respect to the module
• See Design Notes section below for details on pin connections.
• * Refer to the Writing Custom Firmware section for instructions on using these pins if JTAG
functions are needed.
Š 2014 Digi International Inc.
11
XBee®/XBee‐PRO® ZB RF Modules
Pin Signals for the XBee ZigBee Through-hole Module
Pin Assignments for XBee Through‐hole Modules
(Low‐asserted signals are distinguished with a horizontal line above signal name.)
Pin #
Name
Direction
Default State
VCC
Description
Power Supply
DOUT / DIO13
Both
Output
UART Data Out
DIN / nCONFIG / DIO14
Both
Input
UART Data In
DIO12/SPI_MISO
Both
Disabled
GPIO/ SPI slave out
nRESET
Input
Input
Module Reset
RSSI PWM / PWMO DIO10
Both
Output
RX signal strength indicator / GPIO
PWM1 / DIO11
Both
Disabled
GPIO
[reserved]
Do Not Connect
nDTR / SLEEP_RQ / DIO8
Both
Input
Pin Sleep Control Line / GPIO
10
GND
Ground
11
SPI_MOSI / DIO4
Both
Disabled
GPIO/ SPI slave in
12
nCTS / DIO7
Both
Output
Clear-to-Send Flow Control / GPIO
13
ON_nSLEEP / DIO9
Both
Output
Module Status Indicator / GPIO
14
VREF
Not connected
15
ASSOCIATE / DIO5
Both
Output
Associate Indicator / GPIO
16
nRTS / DIO6
Both
Input
Request to Send Flow Control / GPIO
17
AD3 / DIO3 / SPI_nSSEL
Both
Disabled
Analog Input / GPIO / SPI Slave Select
18
AD2 / DIO2 / SPI_CLK
Both
Disabled
Analog Input / GPIO / SPI Clock
19
AD1 / DIO1 / SPI_nATTN
Both
Disabled
Analog Input / GPIO / SPI Attention
20
AD0 / DIO0 / CB
Both
Disabled
Analog Input / GPIO / Commissioning Button
Š 2014 Digi International Inc.
12
XBee®/XBee‐PRO® ZB RF Modules
EM357 Pin Mappings
The following table shows how the EM357 pins are used on the XBee.
EM357 Pin #
EM357 Pin Name
XBee (SMT) Pin #
XBee (TH) Pin #
12
RST
Other Usage
Programming
18
PA7
19
PB3
29
16
Used for UART
20
PB4
25
12
Used for UART
21
PA0 / SC2MOSI
16
11
Used for SPI
22
PA1 / SC2MISO
17
Used for SPI
24
PA2 / SC2SCLK
14
18
Used for SPI
25
PA3 / SC2SSEL
15
17
Used for SPI
26
PA4 / PTI_EN
32
19
OTA packet tracing
27
PA5 / PTI_DATA /
BOOTMODE
12
NA
OTA pacet tracing, force embedded serial bootloader, and SPI attention
line
29
PA6
30
PB1 / SC1TXD
Used for UART
31
PB2 / SC1RXD
Used for UART
33
PC2 / JTDO / SWO
26
13
JTAG (see Writing Custom Firmware section)
34
PC3 / JTDI
28
15
JTAG (see Writing Custom Firmware section)
35
PC4 / JTMS / SWDIO
JTAG (see Writing Custom Firmware section)
36
PB0
10
38
PC1 / ADC3
30
17
41
PB7 / ADC2
31
18
42
PB6 / ADC1
33
20
43
PB5 / ADC0
Temperature sensor on PRO version
NOTE: Some lines may not go to the external XBee pins in the programmable secondary processor version.
Design Notes for the XBee ZigBee 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 both a 1F and 8.2pF capacitor
as near to pin 2 on the PCB as possible. If using a switching regulator for your power supply, switching
frequencies above 500kHz are preferred. Power supply ripple should be limited to a maximum 50mV peak to
peak.
Note – For designs using the programmable modules, an additional 10F decoupling cap is recommended near
pin 2 of the module. The nearest proximity to pin 2 of the three caps should be in the following order: 8.2pf,
1F followed by 10F.
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 or low with 30k internal
pull-up or pull-down resistors using the PR and PD software commands. No specific treatment is needed for
unused outputs.
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For applications that need to ensure the lowest sleep current, unconnected inputs should never be left
floating. Use internal or external pull-up or pull-down resistors, or set the unused I/O lines to outputs.
Other pins may be connected to external circuitry for convenience of operation, including the Associate LED
pad (pad 28) and the Commissioning pad (pad 33). The Associate LED pad will flash differently depending on
the state of the module to the network, and a pushbutton attached to pad 33 can enable various join functions
without having to send serial port commands. Please see the commissioning pushbutton and associate LED
section in chapter 7 for more details. The source and sink capabilities are limited to 4mA for pad numbers 3,
4, 5, 10, 12, 14, 15, 16, 17, 25, 26, 28, 29, 30 and 32, and 8mA for pad numbers 7, 8, 24, 31 and 33 on the
SMT module. The source and sink capabilities are limited to 4mA for pad numbers 2, 3, 4, 9, 12, 13, 15, 16,
17, and 19, and 8mA for pad numbers 6, 7, 11, 18,and 20 on the TH module.
The VRef pad (pad 27) is only used on the programmable versions of the SMT modules. For the TH modules, a
VRef pin (Pin #14) is used. For compatibility with other XBee modules, we recommend connecting this pin to
a voltage reference if analog sampling is desired. Otherwise, connect to GND.
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. A recommended PCB footprint for the
module can be found in Appendix C. No other special PCB design considerations are required for integrating
XBee radios except in the antenna section.
The choice of antenna and antenna location is very important for correct performance. With the exception of
the RF Pad variant, XBees do not require additional ground planes on the host PCB. In general, antenna
elements radiate perpendicular to the direction they point. Thus a vertical antenna emits across the horizon.
Metal objects near the antenna cause reflections and may reduce the ability for an antenna to radiate
efficiently. Metal objects between the transmitter and receiver can also block the radiation path or reduce the
transmission distance, so external antennas should be positioned away from them as much as possible. Some
objects that are often overlooked are metal poles, metal studs or beams in structures, concrete (it is usually
reinforced with metal rods), metal enclosures, vehicles, elevators, ventilation ducts, refrigerators, microwave
ovens, batteries, and tall electrolytic capacitors.
Design Notes for PCB Antenna Modules
PCB Antenna modules should not have any ground planes or metal objects above or below the antenna.
For best results, the module should not be placed in a metal enclosure, which may greatly reduce the
range. The module should be placed at the edge of the PCB on which it is mounted. The ground, power
and signal planes should be vacant immediately below the antenna section. The drawing on the
following page illustrates important recommendations for designing with the PCB Antenna module. It
should be noted that for optimal performance, this module should not be mounted on the RF Pad
footprint described in the next section because the footprint requires a ground plane within the PCB
Antenna keep out area.
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XBee®/XBee‐PRO® ZB RF Modules
Design Notes for RF Pad Modules
The RF Pad is a soldered antenna connection. The RF signal travels from pin 36 on the module to the
antenna through an RF trace transmission line on the PCB. Please note that any additional components
between the module and antenna will violate modular certification. The RF trace should have a
controlled impedance of 50 ohms. We recommend using a microstrip trace, although coplanar
waveguide may also be used if more isolation is needed. Microstrip generally requires less area on the
PCB than coplanar waveguide. Stripline is not recommended because sending the signal to different PCB
layers can introduce matching and performance problems.
It is essential to follow good design practices when implementing the RF trace on a PCB. The following
figures show a layout example of a host PCB that connects an RF Pad module to a right angle, through
hole RPSMA jack. The top two layers of the PCB have a controlled thickness dielectric material in
between. The second layer has a ground plane which runs underneath the entire RF Pad area. This
ground plane is a distance d, the thickness of the dielectric, below the top layer. The top layer has an RF
trace running from pin 36 of the module to the RF pin of the RPSMA connector. The RF trace's width
determines the impedance of the transmission line with relation to the ground plane. Many online tools
can estimate this value, although the PCB manufacturer should be consulted for the exact width.
Assuming d=0.025", and that the dielectric has a relative permittivity of 4.4, the width in this example
will be approximately 0.045" for a 50 ohm trace. This trace width is a good fit with the module
footprint's 0.060" pad width. Using a trace wider than the pad width is not recommended, and using a
very narrow trace (under 0.010") can cause unwanted RF loss. The length of the trace is minimized by
placing the RPSMA jack close to the module. All of the grounds on the jack and the module are
connected to the ground planes directly or through closely placed vias. Any ground fill on the top layer
should be spaced at least twice the distance d (in this case, at least 0.050") from the microstrip to
minimize their interaction.
Implementing these design suggestions will help ensure that the RF Pad module performs to its
specifications.
PCB Layer 1 of RF Layout Example
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XBee®/XBee‐PRO® ZB RF Modules
PCB Layer 2 of RF Layout Example
Module Operation for Programmable Variant
The modules with the programmable option have a secondary processor with 32k of flash and 2k of RAM. This
allows module integrators to put custom code on the XBee module to fit their own unique needs. The DIN,
DOUT, RTS, CTS, and RESET lines are intercepted by the secondary processor to allow it to be in control of the
data transmitted and received. All other lines are in parallel and can be controlled by either the EM357 or the
MC9SO8QE micro (see Block Diagram for details). The EM357 by default has control of certain lines. These
lines can be released by the EM357 by sending the proper command(s) to disable the desired DIO line(s) (see
XBee Command Reference Tables).
In order for the secondary processor to sample with ADCs, the XBee pin 27 (VREF) must be connected to a
reference voltage.
Digi provides a bootloader that can take care of programming the processor over the air or through the serial
interface. This means that over the air updates can be supported through an XMODEM protocol. The processor
can also be programmed and debugged through a one wire interface BKGD (Pin 9).
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XBee®/XBee‐PRO® ZB RF Modules
XBee Programmable Bootloader
Overview
The XBee Programmable module is equipped with a Freescale MC9S08QE32 application processor. This
application processor comes with a supplied bootloader. This section describes how to interface the customer's
application code running on this processor to the XBee Programmable module's supplied bootloader.
The first section discusses how to initiate firmware updates using the supplied bootloader for wired and overthe-air updates.
Bootloader Software Specifics
Memory Layout
Figure 1 shows the memory map for the MC9S08QE32 application processor.
The supplied bootloader occupies the bottom pages of the flash from 0xF200 to 0xFFFF. Application
code cannot write to this space.
The application code can exist in Flash from address 0x8400 to 0xF1BC. 1k of Flash from 0x8000 to
0x83FF is reserved for Non Volatile Application Data that will not be erased by the bootloader during a
flash update.
A portion of RAM is accessible by both the application and the bootloader. Specifically, there is a shared
data region used by both the application and the bootloader that is located at RAM address 0x200 to
0x215. Application code should not write anything to BLResetCause or AppResetCause unless
informing the bootloader of the impending reset reason. The Application code should not clear
BLResetCause unless it is handling the unexpected reset reason.
To prevent a malfunctioning application from running forever, the Bootloader increments BLResetCause
after each watchdog or illegal instruction reset. If this register reaches above 0x10 the bootloader will
stop running the application for a few minutes to allow an OTA or Local update to occur. If no update is
initiated within the time period, BLResetCause is cleared and the application is started again. To
prevent unexpected halting of the application, the application shall clear or decrement BLResetCause
just before a pending reset. To disable this feature, the application shall clear BLResetCause at the
start of the application.
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XBee®/XBee‐PRO® ZB RF Modules
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XBee®/XBee‐PRO® ZB RF Modules
Operation
Upon reset of any kind, the execution control begins with the bootloader.
If the reset cause is Power-On reset (POR), Pin reset (PIN), or Low Voltage Detect (LVD) reset (LVD)
the bootloader will not jump to the application code if the override bits are set to RTS(D7)=1,
DTR(D5)=0, and DIN(B0)=0. Otherwise, the bootloader writes the reset cause "NOTHING" to the
shared data region, and jumps to the Application.
Reset causes are defined in the file common. h in an enumeration with the following definitions:
typedef enum {
BL_CAUSE_NOTHING
= 0x0000,
BL_CAUSE_NOTHING_COUNT
//PIN, LVD, POR
= 0x0001,//BL_Reset_Cause counter
// Bootloader increments cause every reset
BL_CAUSE_BAD_APP
= 0x0010,//Bootloader considers APP invalid
} BL_RESET_CAUSES;
typedef enum {
APP_CAUSE_NOTHING
= 0x0000,
APP_CAUSE_USE001
= 0x0001,
// 0x0000 to 0x00FF are considered valid for APP use.
APP_CAUSE_USE255
= 0x00FF,
APP_CAUSE_FIRMWARE_UPDATE = 0x5981,
APP_CAUSE_BYPASS_MODE
= 0x4682,
APP_CAUSE_BOOTLOADER_MENU = 0x6A18,
} APP_RESET_CAUSES;
Otherwise, if the reset cause is a "watchdog" or other reset, the bootloader checks the shared memory
region for the APP_RESET_CAUSE. If the reset cause is:
1."APP_CAUSE_NOTHING" or 0x0000 to 0x00FF, the bootloader increments the 
BL_RESET_CAUSES, verifies that it is still less than BL_CAUSE_BAD_APP, and jumps back to 
the application. If the Application does not clear the BL_RESET_CAUSE, it can prevent an 
infinite loop of running a bad application that continues to perform illegal instructions or 
watchdog resets.
2."APP_CAUSE_FIRMWARE_UPDATE", the bootloader has been instructed to update the
application "over-the-air" from a specific 64-bit address. In this case, the bootloader will 
attempt to initiate an Xmodem transfer from the 64-bit address located in shared RAM.
3."APP_CAUSE_BYPASS_MODE", the bootloader executes bypass mode. This mode passes the 
local UART data directly to the EM357 allowing for direct communication with the EM357. 
The only way to exit bypass mode is to reset or power cycle the module.
If none of the above is true, the bootloader will enter "Command mode". In this mode, users can
initiate firmware downloads both wired and over-the-air, check application/bootloader version strings,
and enter Bypass mode.
Application version string
Figure 1 shows an "Application version string pointer" area in application flash which holds the pointer
to where the application version string resides. The application's linker command file ultimately
determines where this string is placed in application flash.
It is preferable that the application version string be located at address 0x8400 for MC9S08QE32 parts.
The application string can be any characters terminated by the NULL character (0x00). There is not a
strict limit on the number of characters in the string, but for practical purposes should be kept under
100 bytes including the terminating NULL character. During an update the bootloader erases the entire
application from 0x8400 on. The last page has the vector table specifically the redirected reset vector.
The version string pointer and reset vector are used to determine if the application is valid.
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XBee®/XBee‐PRO® ZB RF Modules
Application Interrupt Vector table and Linker Command File
Since the bootloader flash region is read-only, the interrupt vector table is redirected to the region
0xF1C0 to 0xF1FD so that application developers can use hardware interrupts. Note that in order for
Application interrupts to function properly, the Application's linker command file (*.prm extension)
must be modified appropriately to allow the linker to place the developers code in the correct place in
memory. For example, the developer desires to use the serial communications port SCI1 receive
interrupt. The developer would add the following line to the Codewarrior linker command file for the
project:
VECTOR ADDRESS 0x0000F1E0 vSci1Rx
This will inform the linker that the interrupt function "vSci1Rx()" should be placed at address
0x0000F1E0. Next, the developer should add a file to their project "vector_table.c" that creates an
array of function pointers to the ISR routines used by the application.
extern void _Startup(void);/* _Startup located in Start08.c */
extern void vSci1Rx(void);/* sci1 rx isr */
extern short iWriteToSci1(unsigned char *);
void vDummyIsr(void);
#pragma CONST_SEG VECTORS
void (* const vector_table[])(void) = /* Relocated Interrupt vector table */{
vDummyIsr,/* Int.no. 0 Vtpm3ovf (at F1C0)Unassigned */
vDummyIsr, /* Int.no. 1 Vtpm3ch5 (at F1C2)
Unassigned */
vDummyIsr, /* Int.no. 2 Vtpm3ch4 (at F1C4)
Unassigned */
vDummyIsr, /* Int.no. 3 Vtpm3ch3 (at F1C6)
Unassigned */
vDummyIsr, /* Int.no. 4 Vtpm3ch2 (at F1C8)
Unassigned */
vDummyIsr, /* Int.no. 5 Vtpm3ch1 (at F1CA)
Unassigned */
vDummyIsr, /* Int.no. 6 Vtpm3ch0 (at F1CC)
Unassigned */
vDummyIsr, /* Int.no. 7 Vrtc (at F1CE)
Unassigned */
vDummyIsr, /* Int.no. 8 Vsci2tx (at F1D0)
Unassigned */
vDummyIsr, /* Int.no. 9 Vsci2rx (at F1D2)
Unassigned */
vDummyIsr, /* Int.no. 10 Vsci2err (at F1D4)
Unassigned */
vDummyIsr, /* Int.no. 11 Vacmpx (at F1D6)
Unassigned */
vDummyIsr, /* Int.no. 12 Vadc (at F1D8)
Unassigned */
vDummyIsr, /* Int.no. 13 Vkeyboard (at F1DA)
vDummyIsr, /* Int.no. 14 Viic (at F1DC)
vDummyIsr, /* Int.no. 15 Vsci1tx (at F1DE)
vSci1Rx,
/* Int.no. 16 Vsci1rx (at F1E0)
Unassigned */
Unassigned */
Unassigned */
SCI1RX */
vDummyIsr, /* Int.no. 17 Vsci1err (at F1E2)
vDummyIsr, /* Int.no. 18 Vspi (at F1E4)
Unassigned */
Unassigned */
vDummyIsr, /* Int.no. 19 VReserved12 (at F1E6) Unassigned */
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vDummyIsr, /* Int.no. 20 Vtpm2ovf (at F1E8)
Unassigned */
vDummyIsr, /* Int.no. 21 Vtpm2ch2 (at F1EA)
Unassigned */
vDummyIsr, /* Int.no. 22 Vtpm2ch1 (at F1EC)
Unassigned */
vDummyIsr, /* Int.no. 23 Vtpm2ch0 (at F1EE)
Unassigned */
vDummyIsr, /* Int.no. 24 Vtpm1ovf (at F1F0)
Unassigned */
vDummyIsr, /* Int.no. 25 Vtpm1ch2 (at F1F2)
Unassigned */
vDummyIsr, /* Int.no. 26 Vtpm1ch1 (at F1F4)
Unassigned */
vDummyIsr, /* Int.no. 27 Vtpm1ch0 (at F1F6)
Unassigned */
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XBee®/XBee‐PRO® ZB RF Modules
vDummyIsr, /* Int.no. 28 Vlvd (at F1F8)
Unassigned */
vDummyIsr, /* Int.no. 29 Virq (at F1FA)
Unassigned */
vDummyIsr, /* Int.no. 30 Vswi (at F1FC)
_Startup
/* Int.no. 31 Vreset (at F1FE)
Unassigned */
Reset vector */
};
void vDummyIsr(void){
for(;;){
if(iWriteToSci1("STUCK IN UNASSIGNED ISR\n\r>"));
The interrupt routines themselves can be defined in separate files. The "vDummyIsr" function is used
in conjunction with "iWritetoSci1" for debugging purposes.
Bootloader Menu Commands
The bootloader accepts commands from both the local UART and OTA. All OTA commands sent must be
Unicast with only 1 byte in the payload for each command. A response will be returned to the sender. All
Broadcast and multiple byte OTA packets are dropped to help prevent general OTA traffic from being
interpreted as a command to the bootloader while in the menu.
Bypass Mode - "B"
The bootloader provides a "bypass" mode of operation that essentially connects the SCI1 serial
communications peripheral of the freescale mcu to the EM357's serial Uart channel. This allows direct
communication to the EM357 radio for the purpose of firmware and radio configuration changes. Once
in bypass mode, the X-CTU utility can change modem configuration and/or update EM357 firmware.
Bypass mode automatically handles any baud rate up to 115.2kbps. Note that this command is
unavailable when module is accessed remotely.
Update Firmware - "F"
The "F" command initiates a firmware download for both wired and over-the-air configurations.
Depending on the source of the command (received via Over the Air or local UART), the download will
proceed via wired or over-the-air respectively.
Adjust Timeout for Update Firmware - "T"
The "T" command changes the timeout before sending a NAK by Base-Time*2^(T). The Base-Time for
the local UART is different than the Base-Time for Over the Air. During a firmware update, the
bootloader will automatically increase the Timeout if repeat packets are received or multiple NAKs for
the same packet without success occur.
Application Version String - "A"
The "A" command provides the version of the currently loaded application. If no application is present,
"Unkown" will be returned.
Bootloader Version String - "V"
The "V" command provides the version of the currently loaded bootloader. The version will return a
string in the format BLFFF-HHH-XYZ_DDD where FFF represents the Flash size in kilo bytes, HHH is the
hardware, XYZ is the version, and DDD is the preferred XMODEM packet size for updates. Double the
preferred packet size is also possible, but not guaranteed. For example "BL032-2B0-023_064" will take
64 byte CRC XMODEM payloads and may take 128 byte CRC XMODEM payloads also. In this case, both
64 and 128 payloads are handled, but the 64 byte payload is preferred for better Over the Air
reliability.
Bootloader Version BL032-2x0-025_064 only operates at 9600 baud on the local UART as well as
communications to the EM357 Radio. A newer version of the Bootloader BL032-2x0-033_064 or newer
BL032-2B0-XXX_064 has changed the baud rate to 115200 between the Programmable and the EM357
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XBee®/XBee‐PRO® ZB RF Modules
Radio. The EM357 is also set to 115200 as the default baud rate. The default rate of the programmable
local UART is also set to 115200, however, the local UART has an auto baud feature added to detect if
the UART is at the wrong baud rate. If a single character is sent, it will automatically switch to 115200
or 9600 baud.
Firmware Updates
Wired Updates
A user can update their application using the bootloader in a wired configuration with the following
steps:
a. Plug XBee programmable module into a suitable serial port on a PC.
b. Open a hyperterminal (or similar dumb terminal application) session with 115200 baud, no parity, and 8 data bits with one stop bit.
c. Hit Enter to display the bootloader menu.
d. Hit the "F" key to initiate a wired firmware update.
e. A series of "C" characters Will be displayed within the hyperterminal window. At this point,
select the "transfer->send file" menu item. Select the desired flat binary output file.
f. Select "Xmodem" as the protocol.
g. Click "Send" on the "Send File" dialog. The file will be downloaded to the XBee Programmable
module. Upon a successful update, the bootloader will jump to the newly loaded application.
Over-The-Air updates
A user can update their application using the bootloader in an "over-the-air" configuration with the
following steps…(This procedure assumes that the bootloader is running and not the application. The
EM357 baud rate of the programmable module must be set to 115200 baud. The
bootloader only operates at 115200 baud between the Radio and programmable bootloader. The
application must be programmed with some way to support returning to the bootloader in order to
support Over the Air (OTA) updates without local intervention.)
a. The XBee module sending the file OTA (Host module) should be set up with a series 2 Xbee
module with transparent mode firmware.
b. The XBee Programmable module receiving the update (remote module) is configured with API
firmware.
c. Open a hyperterminal session to the host module with no parity, no hardwareflow control, 8
data bits and 1 stop bit. (The host module does not have to operate at the same baud rate as the
remote module.) For faster updates and less latency due to the UART, set the host module to a
faster baud rate. (i.e. 115200)
d.Enter 3 pluses "+++" to place the EM357 in command mode. (or XCTU’s “Modem Configuration”
tab can be used to set the correct parameters)
e. Set the Host Module destination address to the target module’s 64 bit address that the host
module will update (ATDH aabbccdd, ATDL eeffgghh, ATCN, where aabbccddeeffgghh is the hexadecimal 64 bit address of the target module).
f. Hit Enter and the bootloader command menu will be displayed from the remote module. (Note
that the option "B" doesn't exist for OTA)
g. Hit the "F" key to cause the remote module to request the new firmware file over-the-air.
h. The host module will begin receiving "C" characters indicating that the remote module is
requesting an Xmodem CRC transfer. Using XCTU or another terminal program, Select "XMODEM"
file transfer. Select the Binary file to upload/transfer. Click Send to start the transfer. At the conclusion of a successful transfer, the bootloader will jump to the newly loaded application.
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Output File Configuration
BKGD Programming
P&E Micro provides a background debug tool that allows flashing applications on the MC9S08QE parts
through their background debug mode port. By default, the Codewarrior tool produces an "ABS" output
file for use in programming parts through the background debug interface. The programmable XBee
from the factory has the BKGD debugging capability disabled. In order to debug, a bootloader with the
debug interface enabled needs to be loaded on the secondary processor or a stand-alone app needs to
be loaded.
Bootloader updates
The supplied bootloader requires files in a "flat binary" format which differs from the default ABS file
produced. The Codewarrior tool also produces a S19 output file. In order to successfully flash new
applications, the S19 file must be converted into the flat binary format. Utilities are available on the
web that will convert S19 output to "BIN" outputs. Often times, the "BIN" file conversion will pad the
addresses from 0x0000 to the code space with the same number. (Often 0x00 or 0xFF) These extra
bytes before the APP code starts will need to be deleted from the bin file before the file can be
transferred to the bootloader.
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2. XBee ZigBee RF Module Operation
XBee ZigBee Serial Communications
XBee RF Modules interface to a host device through a serial port. Through its serial port, the module can
communicate with any logic and voltage compatible UART, through a level translator to any serial device (for
example, through a RS-232 or USB interface board), or through a Serial Peripheral Interface, which is a synchronous
interface to be described later.
Two Wire serial Interface (TWI) is also available, but not supported by Digi. For information on the TWI, see the
EM357 specification.
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.
System Data Flow Diagram in a UART‐interfaced environment
(Low‐asserted signals distinguished with horizontal line over signal name.)
DIN (data in)
DIN (data in)
DOUT (data out)
DOUT (data out)
Serial Data
Data enters the module UART through the DIN (pin 4) as an asynchronous serial signal. The signal 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.
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, parity, and stop bits settings on the XBee module can be configured with the BD, NB,
and SB commands respectively. See the command table in chapter 10 for details.
XBee ZigBee SPI Communications
The XBee modules support SPI communications in slave mode. Slave mode receives the clock signal and data
from the master and returns data to the master. The SPI port uses the following signals on the XBee:
• SPI_MOSI (Master Out, Slave In) - inputs serial data from the master
• SPI_MISO (Master In, Slave Out) - outputs serial data to the master
• SPI_SCLK (Serial Clock) - clocks data transfers on MOSI and MISO
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XBee®/XBee‐PRO® ZB RF Modules
• SPI_SSEL (Slave Select) - enables serial communication with the slave
The above four pins are standard for SPI. This module also supports an additional pin, which may be configured
to alert the SPI master when it has data to send. This pin is called SPI_ATTN. If the master monitors this pin
(through polling or interrupts), it can know when it needs to receive data from the module. SPI_ATTN asserts
whenever it has data to send and it remains asserted until all available data has been shifted out to the SPI
master.
In this mode, the following apply:
• Data/Clock rates of up to 5 Mbps are possible
• Data is MSB first
• Frame Format mode 0 is used (see below)
Frame Format for SPI Communications
SPI Operation
When the slave select (SPI_SSEL) signal is asserted by the master, SPI transmit data is driven to the output
pin (SPI_MISO), and SPI data is received from the input pin SPI_MOSI. The SPI_SSEL pin has to be
asserted to enable the transmit serializer to drive data to the output signal SPI_MISO. A rising edge on
SPI_SSEL resets the SPI slave shift registers.
If the SPI_SCLK is present, the SPI_MISO line is always driven whether with or without the SPI_SSEL line
driven. This is a known issue with the Ember EM357 chip, and makes additional hardware necessary if
multiple slaves are using the same bus as the XBee.
If the input buffer is empty, the SPI serializer transmits a busy token (0xFF). Otherwise, all transactions on
the SPI port use API operation. See Chapter 9 - API Operation for more information.
The SPI slave controller must guarantee that there is time to move new transmit data from the transmit
buffer into the hardware serializer. To provide sufficient time, the SPI slave controller inserts a byte of
padding at the start of every new string of transmit data. Whenever the transmit buffer is empty and data
is placed into the transmit buffer, the SPI hardware inserts a byte of padding onto the front of the
transmission as if this byte were placed there by software.
Serial Port Selection
In the default configuration the UART and SPI ports will both be configured for serial port operation.
If DOUT is held low during boot, then only SPI will be used. If both interfaces are configured, serial data will
go out the UART until the SPI_SSEL signal is asserted. Thereafter, all serial communications will operate on
the SPI interface.
If only the UART is enabled, then only the UART will be used, and SPI_SSEL will be ignored. If only the SPI
is enabled, then only the SPI will be used.
If neither serial port is enabled, the module will not support serial operations and all communications must
occur over the air. All data that would normally go to the serial port is discarded.
XBee ZigBee Serial Buffers
The XBee modules maintain small buffers to collect received serial and RF data, which is illustrated in the figure
below. The serial receive buffer collects incoming serial characters and holds them until they can be processed.
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XBee®/XBee‐PRO® ZB RF Modules
The serial transmit buffer collects data that is received via the RF link that will be transmitted out the UART or
SPI port.
Internal Data Flow Diagram
Serial
Receiver
Buffer
DIN or MOSI
CTS
(If D7 is 1 and
UART is in use)
DOUT or MISO
RF TX
Buffer
Transmitter
RF Switch
Antenna
Port
Processor
Serial Transmit
Buffer
RF RX
Buffer
Receiver
RTS
(If UART is in
use, ignored unless D6 is 1)
Serial Receive Buffer
When serial data enters the RF module through the serial port, the data is stored in the serial receive buffer
until it can be processed. Under certain conditions, the module may receive data when the serial receive
buffer is already full. In that case the data is discarded.
The serial receive buffer becomes full when data is streaming into the serial port faster than it can be
processed and sent over the air (OTA). While the speed of receiving the data on the serial port can be
much faster than the speed of transmitting to data for a short period, sustained operation in that mode will
cause data to be dropped due to running out of places in the module to put the data. Some things that
may delay over the air transmissions are address discovery, route discovery, and retransmissions.
Processing received RF data can also take away time and resources for processing incoming serial data.
If the UART is the serial port and CTS flow control is enabled, the external data source is alerted when the
receive buffer is almost full. Then the host holds off sending data to the module until the module asserts
CTS again, allowing more data to come in.
If the SPI is the serial port, no hardware flow control is available. It is the user's responsibility to ensure
that that receive buffer is not overflowed. One reliable strategy is to wait for a TX_STATUS response after
each frame sent to ensure that the module has had time to process it.
Serial Transmit Buffer
When RF data is received, the data is moved into the serial transmit buffer and sent out the UART or SPI
port. If the serial transmit buffer becomes full enough such that all data in a received RF packet won't fit in
the serial transmit buffer, the entire RF data packet is dropped.
Cases in which the serial transmit buffer may become full resulting in dropped RF packets:
If the RF data rate is set higher than the interface data rate of the module, the module could
receive data faster than it can send the data to the host.
If the host does not allow the module to transmit data out from the serial transmit buffer because
of being held off by hardware flow control.
UART Flow Control
The RTS and CTS module pins can be used to provide RTS and/or CTS flow control. CTS flow control provides an
indication to the host to stop sending serial data to the module. RTS flow control allows the host to signal the
module to not send data in the serial transmit buffer out the UART. RTS and CTS flow control are enabled using
the D6 and D7 commands. Please note that serial port flow control is not possible when using the SPI port.
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CTS Flow Control
If CTS flow control is enabled (D7 command), when the serial receive buffer is 17 bytes away from being
full, the module de-asserts CTS (sets it high) to signal to the host device to stop sending serial data. CTS is
re-asserted after the serial receive buffer has 34 bytes of space.
RTS Flow Control
If RTS flow control is enabled (D6 command), data in the serial transmit buffer will not be sent out the
DOUT pin as long as RTS is de-asserted (set high). The host device should not de-assert RTS for long
periods of time to avoid filling the serial transmit buffer. If an RF data packet is received, and the serial
transmit buffer does not have enough space for all of the data bytes, the entire RF data packet will be
discarded.
Note: If the XBee is sending data out the UART when RTS is de-asserted (set high), the XBee could send up to 5 characters out the UART or SPI port after RTS is de-asserted.
XBee ZigBee Break Control
If break is enabled for over five seconds, the XBee will reset. Then it will boot with default baud settings into
command mode.
This break function will be disabled if either P3 or P4 are not enabled.
Serial Interface Protocols
The XBee modules support both transparent and API (Application Programming Interface) serial interfaces.
Transparent Operation
When operating in transparent mode, the modules act as a serial line replacement. All UART or SPI data
received through the DIN or MOSI pin is queued up for RF transmission. When RF data is received, the data
is sent out through the serial port. The module configuration parameters are configured using the AT
command mode interface. Please note that transparent operation is not provided when using the SPI.
Data is buffered in the serial receive buffer until one of the following causes the data to be packetized and
transmitted:
•No serial characters are received for the amount of time determined by the RO (Packetization Timeout) parameter. If RO = 0, packetization begins when a character is received.
•The Command Mode Sequence (GT + CC + GT) is received. Any character buffered in the serial
receive buffer before the sequence is transmitted.
•The maximum number of characters that will fit in an RF packet is received.
API Operation
API operation is an alternative to 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 serial port) include:
•RF Transmit Data Frame
•Command Frame (equivalent to AT commands)
Receive Data Frames (sent out the serial port) 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 application 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, and payload information from received data packets.
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The API operation option facilitates many operations such as the examples cited below:
->
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
A Comparison of Transparent and API Operation
The following table compares the advantages of transparent and API modes of operation:
Transparent Operation Features
Simple Interface
All received serial data is transmitted unless the module is in command mode.
Easy to support
It is easier for an application to support transparent operation and command mode
API Operation Features
Transmitting RF data to multiple remotes only requires changing the address in the API frame. This
process is much faster than in transparent operation where the application must enter AT command
Easy to manage data
transmissions to multiple mode, change the address, exit command mode, and then transmit data.
destinations
Each API transmission can return a transmit status frame indicating the success or reason for
failure.
Received data frames
indicate the sender's
address
All received RF data API frames indicate the source address.
Advanced ZigBee
addressing support
API transmit and receive frames can expose ZigBee addressing fields including source and
destination endpoints, cluster ID and profile ID. This makes it easy to support ZDO commands and
public profile traffic.
Advanced networking
diagnostics
API frames can provide indication of IO samples from remote devices, and node identification
messages.
Remote Configuration
Set / read configuration commands can be sent to remote devices to configure them as needed
using the API.
As a general rule of thumb, API mode is recommended when a device:
• sends RF data to multiple destinations
• sends remote configuration commands to manage devices in the network
• receives RF data packets from multiple devices, and the application needs to know which device sent
which packet
• must support multiple ZigBee endpoints, cluster IDs, and/or profile IDs
• uses the ZigBee Device Profile services.
API mode is required when:
• using Smart Energy firmware
• using SPI for the serial port
• receiving I/O samples from remote devices
• using source routing
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.
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XBee ZigBee 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.
Transmit Mode Sequence
Successful
Transmission
Idle Mode
New
Transmission
16-bit Network
Address Known?
Yes
16-bit Network
Address Discovery
No
Transmit Data
No
No
16-bit Network
Address Discovered?
Yes
Route Known?
Route Discovery
Yes
Route Discovered?
Yes
No
Data Discarded
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XBee®/XBee‐PRO® ZB RF Modules
When data is transmitted from one node to another, a network-level acknowledgement is transmitted back
across the established route to the source node. This acknowledgement packet indicates to the source node that
the data packet was received by the destination node. If a network acknowledgement is not received, the
source node will re-transmit the data.
It is possible in rare circumstances for the destination to receive a data packet, but for the source to not receive
the network acknowledgment. In this case, the source will retransmit the data, which could cause the
destination to receive the same data packet multiple times. The XBee modules do not filter out duplicate
packets. The application should include provisions to address this potential issue
See Data Transmission and Routing in chapter 4 for more information.
Receive Mode
If a valid RF packet is received, the data is transferred to the serial transmit buffer.
Command Mode
To modify or read RF Module parameters, the module must first enter into Command Mode - a state in which
incoming serial characters are interpreted as commands. Command Mode is only available over the UART when
not using the Smart Energy firmware. The API Mode section in Chapter 9 describes an alternate means for
configuring modules which is available with the SPI and with Smart Energy, as well as over the UART with ZB
code.
AT Command Mode
To Enter AT Command Mode:
Send the 3-character command sequence “+++” and observe guard times before and after the command characters. [Refer to the “Default AT Command Mode Sequence” below.]
Default AT Command Mode Sequence (for transition to Command Mode):
•No characters sent for one second [GT (Guard Times) parameter = 0x3E8]
•Input three plus characters (“+++”) within one second [CC (Command Sequence Character) parameter = 0x2B.]
•No characters sent for one second [GT (Guard Times) parameter = 0x3E8]
Once the AT command mode sequence has been issued, the module sends an "OK\r" out the UART pad. The
"OK\r" characters can be delayed if the module has not finished transmitting received serial data.
When command mode has been entered, the command mode timer is started (CT command), and the
module is able to receive AT commands on the UART port.
All of the parameter values in the sequence can be modified to reflect user preferences.
NOTE: Failure to enter AT Command Mode is most commonly due to baud rate mismatch. By default,
the BD (Baud Rate) parameter = 3 (9600 bps).
To Send AT Commands:
Send AT commands and parameters using the syntax shown below.
Syntax for sending AT Commands
“AT”
Prefix
ASCII
Space
Parameter
Command (optional) (optional, HEX)
Carriage
Return
Example: ATDL 1F
To read a parameter value stored in the RF module’s register, omit the parameter field.
The preceding example would change the RF module Destination Address (Low) to “0x1F”. To store the new
value to non-volatile (long term) memory, subsequently send the WR (Write) command.
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For modified parameter values to persist in the module’s registry after a reset, changes must be saved to
non-volatile memory using the WR (Write) Command. Otherwise, parameters are restored to previously
saved values after the module is reset.
Command Response
When a command is sent to the module, the module will parse and execute the command. Upon
successful execution of a command, the module returns an “OK” message. If execution of a command
results in an error, the module returns an “ERROR” message.
Applying Command Changes
Any changes made to the configuration command registers through AT commands will not take effect until
the changes are applied. For example, sending the BD command to change the baud rate will not change
the actual baud rate until changes are applied. Changes can be applied in one of the following ways:
•The AC (Apply Changes) command is issued.
•AT command mode is exited.
To Exit AT Command Mode:
1. Send the ATCN (Exit Command Mode) command (followed by a carriage return).
[OR]
2. If no valid AT Commands are received within the time specified by CT (Command Mode Timeout)
Command, the RF module automatically returns to Idle Mode.
For an example of programming the RF module using AT Commands and descriptions of each configurable parameter, please see the Command Reference Table chapter.
Sleep Mode
Sleep modes allow the RF module to enter states of low power consumption when not in use. XBee RF modules
support both pin sleep (sleep mode entered on pin transition) and cyclic sleep (module sleeps for a fixed time).
XBee sleep modes are discussed in detail in chapter 7.
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3. XBee ZigBee Networks
Introduction to ZigBee
ZigBee is an open global standard built on the IEEE 802.15.4 MAC/PHY. ZigBee defines a network layer above the
802.15.4 layers to support advanced mesh routing capabilities. The ZigBee specification is developed by a growing
consortium of companies that make up the ZigBee Alliance. The Alliance is made up of over 300 members, including
semiconductor, module, stack, and software developers.
ZigBee Stack Layers
The ZigBee stack consists of several layers including the PHY, MAC, Network, Application Support Sublayer (APS),
and ZigBee Device Objects (ZDO) layers. Technically, an Application Framework (AF) layer also exists, but will be
grouped with the APS layer in remaining discussions. The ZigBee layers are shown in the figure below.
A description of each layer appears in the following table:
ZigBee Layer
Description
PHY
Defines the physical operation of the ZigBee device including receive
sensitivity, channel rejection, output power, number of channels, chip
modulation, and transmission rate specifications. Most ZigBee
applications operate on the 2.4 GHz ISM band at a 250kbps data rate.
See the IEEE 802.15.4 specification for details.
MAC
Manages RF data transactions between neighboring devices (point to
point). The MAC includes services such as transmission retry and
acknowledgment management, and collision avoidance techniques
(CSMA-CA).
Network
Adds routing capabilities that allows RF data packets to traverse multiple
devices (multiple "hops") to route data from source to destination (peer to
peer).
APS (AF)
Application layer that defines various addressing objects including
profiles, clusters, and endpoints.
ZDO
Application layer that provides device and service discovery features and
advanced network management capabilities.
XigBee Networking Concepts
Device Types
ZigBee defines three different device types: coordinator, router, and end device.
Node Types / Sample of a Basic ZigBee Network Topology
A coordinator has the following characteristics: It ...
•Selects a channel and PAN ID (both 64-bit and 16-bit) to start the network
•Can allow routers and end devices to join the network
•Can assist in routing data
•Cannot sleep--should be mains powered
•Can buffer RF data packets for sleeping end device children.
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A router has the following characteristics: It ...
•Must join a ZigBee PAN before it can transmit, receive, or route data
•After joining, can allow routers and end devices to join the network
•After joining, can assist in routing data
•Cannot sleep--should be mains powered.
•Can buffer RF data packets for sleeping end device children.
An end device has the following characteristics: It ...
•Must join a ZigBee PAN before it can transmit or receive data
•Cannot allow devices to join the network
•Must always transmit and receive RF data through its parent, and cannot route data.
•Can enter low power modes to conserve power and can be battery-powered.
An example of such a network is shown below:
In ZigBee networks, the coordinator must select a PAN ID (64-bit and 16-bit) and channel to start a network.
After that, it behaves essentially like a router. The coordinator and routers can allow other devices to join the
network and can route data.
After an end device joins a router or coordinator, it must be able to transmit or receive RF data through that
router or coordinator. The router or coordinator that allowed an end device to join becomes the "parent" of the
end device. Since the end device can sleep, the parent must be able to buffer or retain incoming data packets
destined for the end device until the end device is able to wake and receive the data.
A module can only operate as one of the three device types. The device type is selected by configuration rather
than by firmware image as was the case on earlier hardware platforms.
By default, the module operates as a router in transparent mode. To select coordinator operation, set CE to 1.
To select end device operation, set SM to a non-zero value. To select router operation, both CE and SM must be
0.
One complication is that if a device is a coordinator and it needs to be changed into an end device, CE must be
set back to 0 first. If not, the SM configuration will conflict with the CE configuration. Likewise, to change an
end device into a coordinator, it must be changed into a router first.
Another complication is that default parameters for a router build don't always work very well for a coordinator
build. For example:
DH/DL is 0 by default, which allows routers and end devices to send data to the coordinator when they first
come up. If DH/DL is not changed from the default value when the device is changed to a coordinator, then the
device will send data to itself, causing characters to be echoed back to the screen as they are typed. Since this
is probably not the desired operation, DH/DL should be set to the broadcast address or some specific unicast
address when the device is changed to a coordinator.
Another example is EO for smart energy builds. This value should be 08 for routers and end devices and it
should be 02 for the coordinator to designate it as the trust center. Therefore, if using authentication, which is
the normal case for Smart Energy builds, EO should be changed from 02 to 08 when CE is set to 1.
In general, when changing device types, it is the user's responsibility to ensure that parameters are set to be
compatible with the new device type.
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PAN ID
ZigBee networks are called personal area networks or PANs. Each network is defined with a unique PAN
identifier (PAN ID). This identifier is common among all devices of the same network. ZigBee devices are either
preconfigured with a PAN ID to join, or they can discover nearby networks and select a PAN ID to join.
ZigBee supports both a 64-bit and a 16-bit PAN ID. Both PAN IDs are used to uniquely identify a network.
Devices on the same ZigBee network must share the same 64-bit and 16-bit PAN IDs. If multiple ZigBee
networks are operating within range of each other, each should have unique PAN IDs.
The 16-bit PAN ID is used as a MAC layer addressing field in all RF data transmissions between devices in a
network. However, due to the limited addressing space of the 16-bit PAN ID (65,535 possibilities), there is a
possibility that multiple ZigBee networks (within range of each other) could use the same 16-bit PAN ID. To
resolve potential 16-bit PAN ID conflicts, the ZigBee Alliance created a 64-bit PAN ID.
The 64-bit PAN ID (also called the extended PAN ID), is intended to be a unique, non-duplicated value. When a
coordinator starts a network, it can either start a network on a preconfigured 64-bit PAN ID, or it can select a
random 64-bit PAN ID. The 64-bit PAN ID is used during joining; if a device has a preconfigured 64-bit PAN ID,
it will only join a network with the same 64-bit PAN ID. Otherwise, a device could join any detected PAN and
inherit the PAN ID from the network when it joins. The 64-bit PAN ID is included in all ZigBee beacons and is
used in 16-bit PAN ID conflict resolution.
Routers and end devices are typically configured to join a network with any 16-bit PAN ID as long as the 64-bit
PAN ID is valid. Coordinators typically select a random 16-bit PAN ID for their network.
Since the 16-bit PAN ID only allows up to 65,535 unique values, and since the 16-bit PAN ID is randomly
selected, provisions exist in ZigBee to detect if two networks (with different 64-bit PAN IDs) are operating on
the same 16-bit PAN ID. If such a conflict is detected, the ZigBee stack can perform PAN ID conflict resolution to
change the 16-bit PAN ID of the network in order to resolve the conflict. See the ZigBee specification for details.
To summarize, ZigBee routers and end devices should be configured with the 64-bit PAN ID of the network they
want to join. They typically acquire the 16-bit PAN ID when they join a network.
Operating Channel
ZigBee utilizes direct-sequence spread spectrum modulation and operates on a fixed channel. The 802.15.4 PHY
defines 16 operating channels (channels 11 to 26) in the 2.4 GHz frequency band. XBee modules support all 16
channels.
ZigBee Application Layers: In Depth
This section provides a more in-depth look at the ZigBee application stack layers (APS, ZDO) including a discussion
on ZigBee endpoints, clusters, and profiles. Much of the material in this section can introduce unnecessary details of
the ZigBee stack that are not required in many cases.
Skip this section if
•The XBee does not need to interoperate or talk to non-Digi ZigBee devices
•The XBee simply needs to send data between devices.
Read this section if
•The XBee may talk to non-Digi ZigBee devices
•The XBee requires network management and discovery capabilities of the ZDO layer
•The XBee needs to operate in a public application profile (smart energy, home automation, etc.)
Application Support Sublayer (APS)
The APS layer in ZigBee adds support for application profiles, cluster IDs, and endpoints.
Application Profiles
Application profiles specify various device descriptions including required functionality for various devices. The
collection of device descriptions forms an application profile. Application profiles can be defined as "Public" or
"Private" profiles. Private profiles are defined by a manufacturer whereas public profiles are defined, developed,
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XBee®/XBee‐PRO® ZB RF Modules
and maintained by the ZigBee Alliance. Each application profile has a unique profile identifier assigned by the
ZigBee Alliance.
Examples of public profiles include:
•Home Automation
•Smart Energy
•Commercial Building Automation
The Smart Energy profile, for example, defines various device types including an energy service portal, load
controller, thermostat, in-home display, etc. The Smart Energy profile defines required functionality for each
device type. For example, a load controller must respond to a defined command to turn a load on or off. By
defining standard communication protocols and device functionality, public profiles allow interoperable ZigBee
solutions to be developed by independent manufacturers.
Digi XBee ZB firmware operates on a private profile called the Digi Drop-In Networking profile. However, API
mode can be used in many cases to talk to devices in public profiles or non-Digi private profiles. See the API
Operations chapter for details.
Clusters
A cluster is an application message type defined within a profile. Clusters are used to specify a unique
function, service, or action. For example, the following are some clusters defined in the home automation
profile:
•On/Off - Used to switch devices on or off (lights, thermostats, etc.)
•Level Control - Used to control devices that can be set to a level between on and off
•Color Control - Controls the color of color capable devices.
Each cluster has an associated 2-byte cluster identifier (cluster ID). The cluster ID is included in all
application transmissions. Clusters often have associated request and response messages. For example, a
smart energy gateway (service portal) might send a load control event to a load controller in order to
schedule turning on or off an appliance. Upon executing the event, the load controller would send a load
control report message back to the gateway.
Devices that operate in an application profile (private or public) must respond correctly to all required
clusters. For example, a light switch that will operate in the home automation public profile must correctly
implement the On/Off and other required clusters in order to interoperate with other home automation
devices. The ZigBee Alliance has defined a ZigBee Cluster Library (ZCL) that contains definitions or various
general use clusters that could be implemented in any profile.
XBee modules implement various clusters in the Digi private profile. In addition, the API can be used to
send or receive messages on any cluster ID (and profile ID or endpoint). See the Explicit Addressing ZigBee
Command API frame in chapter 3 for details.
Endpoints
The APS layer includes supports for endpoints. An endpoint can be thought of as a running application,
similar to a TCP/IP port. A single device can support one or more endpoints. Each application endpoint is
identified by a 1-byte value, ranging from 1 to 240. Each defined endpoint on a device is tied to an
application profile. A device could, for example, implement one endpoint that supports a Smart Energy load
controller, and another endpoint that supports other functionality on a private profile.
ZigBee Device Profile
Profile ID 0x0000 is reserved for the ZigBee Device Profile. This profile is implemented on all ZigBee
devices. Device Profile defines many device and service discovery features and network management
capabilities. Endpoint 0 is a reserved endpoint that supports the ZigBee Device Profile. This endpoint is
called the ZigBee Device Objects (ZDO) endpoint.
ZigBee Device Objects (ZDO)
The ZDO (endpoint 0) supports the discovery and management capabilities of the ZigBee Device Profile. A
complete listing of all ZDP services is included in the ZigBee specification. Each service has an associated
cluster ID.
The XBee ZB firmware allows applications to easily send ZDO messages to devices in the network using the
API. See the ZDO Transmissions section in chapter 4 for details.
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ZigBee Coordinator Operation
Forming a Network
The coordinator is responsible for selecting the channel, PAN ID (16-bit and 64-bit), security policy, and stack
profile for a network. Since a coordinator is the only device type that can start a network, each ZigBee network
must have one coordinator. After the coordinator has started a network, it can allow new devices to join the
network. It can also route data packets and communicate with other devices on the network.
To ensure the coordinator starts on a good channel and unused PAN ID, the coordinator performs a series of
scans to discover any RF activity on different channels (energy scan) and to discover any nearby operating PANs
(PAN scan). The process for selecting the channel and PAN ID are described in the following sections.
Channel Selection
When starting a network, the coordinator must select a "good" channel for the network to operate on. To do
this, it performs an energy scan on multiple channels (frequencies) to detect energy levels on each channel.
Channels with excessive energy levels are removed from its list of potential channels to start on.
PAN ID Selection
After completing the energy scan, the coordinator scans its list of potential channels (remaining channels after
the energy scan) to obtain a list of neighboring PANs. To do this, the coordinator sends a beacon request
(broadcast) transmission on each potential channel. All nearby coordinators and routers (that have already
joined a ZigBee network) will respond to the beacon request by sending a beacon back to the coordinator. The
beacon contains information about the PAN the device is on, including the PAN identifiers (16-bit and 64-bit).
This scan (collecting beacons on the potential channels) is typically called an active scan or PAN scan.
After the coordinator completes the channel and PAN scan, it selects a random channel and unused 16-bit PAN
ID to start on.
Security Policy
The security policy determines which devices are allowed to join the network, and which device(s) can
authenticate joining devices. See chapter 5 for a detailed discussion of various security policies.
Persistent Data
Once a coordinator has started a network, it retains the following information through power cycle or reset
events:
•PAN ID
•Operating channel
•Security policy and frame counter values
•Child table (end device children that are joined to the coordinator).
•Binding Table
•Group Table
The coordinator will retain this information indefinitely until it leaves the network. When the coordinator leaves
a network and starts a new network, the previous PAN ID, operating channel, and child table data are lost.
XBee ZigBee Coordinator Startup
The following commands control the coordinator network formation process.
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Network formation commands used by the coordinator to form a network.
Command
Description
ID
Used to determine the 64-bit PAN ID. If set to 0 (default), a random 64-bit PAN ID will be selected.
SC
Determines the scan channels bitmask (up to 16 channels) used by the coordinator when forming a
network. The coordinator will perform an energy scan on all enabled SC channels. It will then perform a
PAN ID scan and then form the network on one of the SC channels.
SD
Set the scan duration period. This value determines how long the coordinator performs an energy scan or
PAN ID scan on a given channel.
ZS
Set the ZigBee stack profile for the network.
EE
Enable or disable security in the network.
NK
Set the network security key for the network. If set to 0 (default), a random network security key will be
used.
KY
Set the trust center link key for the network. If set to 0 (default), a random link key will be used.
EO
Set the security policy for the network.
Once the coordinator starts a network, the network configuration settings and child table data persist through
power cycles as mentioned in the "Persistent Data" section.
When the coordinator has successfully started a network, it
• Allows other devices to join the network for a time (see NJ command)
• Sets AI=0
• Starts blinking the Associate LED
• Sends an API modem status frame ("coordinator started") out the serial port when using API mode.
These behaviors are configurable using the following commands:
Command
Description
NJ
Sets the permit-join time on the coordinator, measured in seconds.
D5
Enables the Associate LED functionality.
LT
Sets the Associate LED blink time when joined. Default is 1 blink per
second.
If any of the command values in the network formation commands table changes, the coordinator will leave its
current network and start a new network, possibly on a different channel. Note that command changes must be
applied (AC or CN command) before taking effect.
Permit Joining
The permit joining attribute on the coordinator is configurable with the NJ command. NJ can be configured to
always allow joining, or to allow joining for a short time.
Joining Always Enabled
If NJ=0xFF (default), joining is permanently enabled. This mode should be used carefully. Once a network
has been deployed, the application should strongly consider disabling joining to prevent unwanted joins
from occurring.
Joining Temporarily Enabled
If NJ < 0xFF, joining will be enabled only for a number of seconds, based on the NJ parameter. The timer is
started once the XBee joins a network. Joining will not be re-enabled if the module is power cycled or reset.
The following mechanisms can restart the permit-joining timer:
• Changing NJ to a different value (and applying changes with the AC or CN commands)
• Pressing the commissioning button twice
• Issuing the CB command with a parameter of 2
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The last two cases enable joining for one minute if NJ is 0x0 or 0xFF. Otherwise, the commissioning button
and the CB2 command enable joining for NJ seconds.
Resetting the Coordinator
When the coordinator is reset or power cycled, it checks its PAN ID, operating channel and stack profile against
the network configuration settings (ID, CH, ZS). It also verifies the saved security policy against the security
configuration settings (EE, NK, KY). If the coordinator's PAN ID, operating channel, stack profile, or security
policy is not valid based on its network and security configuration settings, then the coordinator will leave the
network and attempt to form a new network based on its network formation command values.
To prevent the coordinator from leaving an existing network, the WR command should be issued after all
network formation commands have been configured in order to retain these settings through power cycle or
reset events.
Leaving a Network
There are a couple of mechanisms that will cause the coordinator to leave its current PAN and start a new
network based on its network formation parameter values. These include the following:
•Change the ID command such that the current 64-bit PAN ID is invalid.
•Change the SC command such that the current channel (CH) is not included in the channel mask.
•Change the ZS or any of the security command values (excluding NK).
•Issue the NR0 command to cause the coordinator to leave.
•Issue the NR1 command to send a broadcast transmission, causing all devices in the network to leave and
migrate to a different channel.
•Press the commissioning button 4 times or issue the CB command with a parameter of 4.
•Issue a network leave command.
Note that changes to ID, SC, ZS, and security command values only take effect when changes are applied (AC
or CN commands).
Replacing a Coordinator (Security Disabled Only)
In rare occasions, it may become necessary to replace an existing coordinator in a network with a new physical
device. If security is not enabled in the network, a replacement XBee coordinator can be configured with the
PAN ID (16-bit and 64-bit), channel, and stack profile settings of a running network in order to replace an
existing coordinator.
NOTE: Having two coordinators on the same channel, stack profile, and PAN ID (16-bit and 64-bit) can cause
problems in the network and should be avoided. When replacing a coordinator, the old coordinator should be
turned off before starting the new coordinator.
To replace a coordinator, the following commands should be read from a device on the network:
AT Command
Description
OP
Read the operating 64-bit PAN ID.
OI
Read the operating 16-bit PAN ID.
CH
Read the operating channel.
ZS
Read the stack profile.
Each of the commands listed above can be read from any device on the network. (These parameters will be the
same on all devices in the network.) After reading these commands from a device on the network, these
parameter values should be programmed into the new coordinator using the following commands.
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AT Command
Description
ID
Set the 64-bit PAN ID to match the read OP value.
II
Set the initial 16-bit PAN ID to match the read OI value.
SC
Set the scan channels bitmask to enable the read operating channel (CH
command). For example, if the operating channel is 0x0B, set SC to
0x0001. If the operating channel is 0x17, set SC to 0x1000.
ZS
Set the stack profile to match the read ZS value.
Note: II is the initial 16-bit PAN ID. Under certain conditions, the ZigBee stack can change the 16-bit PAN ID of the network. For this reason, the II command cannot be saved using the WR command. Once II is set, the coordinator leaves the
network and starts on the 16-bit PAN ID specified by II.
Example: Starting a Coordinator
1. Set CE (Coordinator Enable) to 1, and use the WR command to save the changes.
2. Set SC and ID to the desired scan channels and PAN ID values. (The defaults should suffice.)
3. If SC or ID is changed from the default, issue the WR command to save the changes.
4. If SC or ID is changed from the default, apply changes (make SC and ID changes take effect)
either by sending the AC command or by exiting AT command mode.
5. The Associate LED will start blinking once the coordinator has selected a channel and PAN ID.
6. The API Modem Status frame ("Coordinator Started") is sent out the serial port when using API
mode.
7. Reading the AI command (association status) will return a value of 0, indicating a successful
startup.
8. Reading the MY command (16-bit address) will return a value of 0, the ZigBee-defined 16-bit
address of the coordinator.
After startup, the coordinator will allow joining based on its NJ value.
Example: Replacing a Coordinator (Security Disabled)
1. Read the OP, OI, CH, and ZS commands on the running coordinator.
2. Set the CE, ID, SC, and ZS parameters on the new coordinator, followed by WR command to
save these parameter values.
3. Turn off the running coordinator.
4. Set the II parameter on the new coordinator to match the read OI value on the old coordinator.
5. Wait for the new coordinator to start (AI=0).
ZigBee Router Operation
Routers must discover and join a valid ZigBee network before they can participate in a ZigBee network. After a
router has joined a network, it can allow new devices to join the network. It can also route data packets and
communicate with other devices on the network.
Discovering ZigBee Networks
To discover nearby ZigBee networks, the router performs a PAN (or active) scan, just like the coordinator does
when it starts a network. During the PAN scan, the router sends a beacon request (broadcast) transmission on
the first channel in its scan channels list. All nearby coordinators and routers operating on that channel (that are
already part of a ZigBee network) respond to the beacon request by sending a beacon back to the router. The
beacon contains information about the PAN the nearby device is on, including the PAN identifier (PAN ID), and
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whether or not joining is allowed. The router evaluates each beacon received on the channel to determine if a
valid PAN is found. A router considers a PAN to be valid if the PAN:
•Has a valid 64-bit PAN ID (PAN ID matches ID if ID > 0)
•Has the correct stack profile (ZS command)
•Is allowing joining.
If a valid PAN is not found, the router performs the PAN scan on the next channel in its scan channels list and
continues scanning until a valid network is found, or until all channels have been scanned. If all channels have
been scanned and a valid PAN was not discovered, all channels will be scanned again.
The ZigBee Alliance requires that certified solutions not send beacon request messages too frequently. To meet
certification requirements, the XBee firmware attempts 9 scans per minute for the first 5 minutes, and 3 scans
per minute thereafter. If a valid PAN is within range of a joining router, it should typically be discovered within a
few seconds.
Joining a Network
Once the router discovers a valid network, it sends an association request to the device that sent a valid beacon
requesting a join on the ZigBee network. The device allowing the join then sends an association response frame
that either allows or denies the join.
When a router joins a network, it receives a 16-bit address from the device that allowed the join. The 16-bit
address is randomly selected by the device that allowed the join.
Authentication
In a network where security is enabled, the router must then go through an authentication process. See the
Security chapter for a discussion on security and authentication.
After the router is joined (and authenticated, in a secure network), it can allow new devices to join the network.
Persistent Data
Once a router has joined a network, it retains the following information through power cycle or reset events:
•PAN ID
•Operating channel
•Security policy and frame counter values
•Child table (end device children that are joined to the coordinator).
•Binding Table
•Group Table
The router will retain this information indefinitely until it leaves the network. When the router leaves a network,
the previous PAN ID, operating channel, and child table data are lost.
XBee ZB Router Joining
When the router is powered on, if it is not already joined to a valid ZigBee network, it immediately attempts to
find and join a valid ZigBee network.
Note: The DJ command can be set to 1 to disable joining. The DJ parameter cannot be written with WR, so a
power cycle always clears the DJ setting.
The following commands control the router joining process.
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Command
Description
ID
Sets the 64-bit PAN ID to join. Setting ID=0 allows the router to join any
64-bit PAN ID.
SC
Set the scan channels bitmask that determines which channels a router
will scan to find a valid network. SC on the router should be set to match
SC on the coordinator. For example, setting SC to 0x281 enables
scanning on channels 0x0B, 0x12, and 0x14, in that order.
SD
Set the scan duration, or time that the router will listen for beacons on
each channel.
ZS
Set the stack profile on the device.
EE
Enable or disable security in the network. This must be set to match the
EE value (security policy) of the coordinator.
KY
Set the trust center link key. If set to 0 (default), the link key is expected to
be obtained (unencrypted) during joining.
Once the router joins a network, the network configuration settings and child table data persist through power
cycles as mentioned in the "Persistent Data" section previously. If joining fails, the status of the last join
attempt can be read in the AI command register.
If any of the above command values change, when command register changes are applied (AC or CN
commands), the router will leave its current network and attempt to discover and join a new valid network.
When a ZB router has successfully joined a network, it:
•Allows other devices to join the network for a time
•Sets AI=0
•Starts blinking the Associate LED
•Sends an API modem status frame ("associated") out the serial port when using API mode.
These behaviors are configurable using the following commands:
Command
Description
NJ
Sets the permit-join time on the router, or the time that it will allow new
devices to join the network, measured in seconds. If NJ=0xFF, permit
joining will always be enabled.
D5
Enables the Associate LED functionality.
LT
Sets the Associate LED blink time when joined. Default is 2 blinks per
second (router).
Permit Joining
The permit joining attribute on the router is configurable with the NJ command. NJ can be configured to always
allow joining, or to allow joining for a short time.
Joining Always Enabled
If NJ=0xFF (default), joining is permanently enabled. This mode should be used carefully. Once a network has
been deployed, the application should strongly consider disabling joining to prevent unwanted joins from
occurring.
Joining Temporarily Enabled
If NJ < 0xFF, joining will be enabled only for a number of seconds, based on the NJ parameter. The timer is
started once the XBee joins a network. Joining will not be re-enabled if the module is power cycled or reset. The
following mechanisms can restart the permit-joining timer:
• Changing NJ to a different value (and applying changes with the AC or CN commands)
• Pressing the commissioning button twice
• Issuing the CB command with a parameter of 2 (software emulation of a 2 button press)
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• Causing the router to leave and rejoin the network.
The middle two cases enable joining for one minute if NJ is 0x0 or 0xFF. Otherwise, the commissioning button
and the CB2 command enable joining for NJ seconds.
Router Network Connectivity
Once a router joins a ZigBee network, it remains connected to the network on the same channel and PAN ID as
long as it is not forced to leave. (See “Leaving a Network” section for details.) If the scan channels (SC), PAN ID
(ID) and security settings (EE, KY) do not change after a power cycle, the router will remain connected to the
network after a power cycle.
If a router may physically move out of range of the network it initially joined, the application should include
provisions to detect if the router can still communicate with the original network. If communication with the
original network is lost, the application may choose to force the router to leave the network (see Leaving a
Network section below for details). The XBee firmware includes two provisions to automatically detect the
presence of a network, and leave if the check fails.
Power-On Join Verification
The JV command (join verification) enables the power-on join verification check. If enabled, the XBee will
attempt to discover the 64-bit address of the coordinator when it first joins a network. Once it has joined, it
will also attempt to discover the 64-bit address of the coordinator after a power cycle event. If 3 discovery
attempts fail, the router will leave the network and try to join a new network. Power-on join verification is
disabled by default (JV defaults to 0).
Network Watchdog
The NW command (network watchdog timeout) can be used for a powered router to periodically check for
the presence of a coordinator to verify network connectivity. The NW command specifies a timeout in
minutes where the router must receive communication from the coordinator or data collector. The following
events restart the network watchdog timer:
•RF data received from the coordinator
•RF data sent to the coordinator and an acknowledgment was received
•Many-to-one route request was received (from any device)
•Changing the value of NW.
If the watchdog timer expires (no valid data received for NW time), the router will attempt to discover the
64-bit address of the coordinator. If the address cannot be discovered, the router records one watchdog
timeout. Once three consecutive network watchdog timeouts have expired (3 * NW) and the coordinator
has not responded to the address discovery attempts, the router will leave the network and attempt to join
a new network. Anytime a router receives valid data from the coordinator or data collector, it will clear the
watchdog timeouts counter and restart the watchdog timer. The watchdog timer (NW command) is settable
to several days. The network watchdog feature is disabled by default (NW defaults to 0).
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Network Watchdog Behavior
Clear Network Watchdog Failure Count
Restart Network Watchdog Timer
Yes
Received RF
Communication from
Coordinator or Data
Collector
No
No
Network Watchdog
Timer Expired?
Yes
Discover Coordinator
Network
Watchdog
Failure Count
=3?
Yes
Coordinator
Found?
No
Network Watchdog Failure
Count +=1
No
Yes
Leave
Leaving a Network
There are a couple of mechanisms that will cause the router to leave its current PAN and attempt to discover
and join a new network based on its network joining parameter values.
These include the following:
• Change the ID command such that the current 64-bit PAN ID is invalid.
• Change the SC command such that the current channel (CH) is not included in the channel mask.
• Change the ZS or any of the security command values.
• Issue the NR0 command to cause the router to leave.
• Issue the NR1 command to send a broadcast transmission, causing all devices in the network to leave and
migrate to a different channel.
• Press the commissioning button 4 times or issue the CB command with a parameter of 4.
• Issue a network leave command.
Note that changes to ID, SC, ZS, and security command values only take effect when changes are applied (AC
or CN commands).
Network Locator Option
The Device Options Network Locator option is provided to support the swapping or replacement of a Coordinator
in a running network. The Network Locator option, if enabled (ATDO80), modifies the behavior of the JV and NW
options. Failure to communicate with the Coordinator does not result in the radio leaving the network, but
instead the radio starts a search for the network across the channels of the Search Channel mask (SC). If the
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network is found on the old channel with the same OI (operating ID) the search mode ends and if NW is
enabled, NW is rescheduled. If the network is found with a new OI but satisfies the radio's search for a matching
ID and ZS, the radio leaves the old network and joins the new network with the new OI.
Resetting the Router
When the router is reset or power cycled, it checks its PAN ID, operating channel and stack profile against the
network configuration settings (ID, SC, ZS). It also verifies the saved security policy is valid based on the
security configuration commands (EE, KY). If the router's PAN ID, operating channel, stack profile, or security
policy is invalid, the router will leave the network and attempt to join a new network based on its network
joining command values.
To prevent the router from leaving an existing network, the WR command should be issued after all network
joining commands have been configured in order to retain these settings through power cycle or reset events.
Example: Joining a Network
After starting a coordinator (that is allowing joins), the following steps will cause a router to join the network:
1. Set ID to the desired 64-bit PAN ID, or to 0 to join any PAN.
2. Set SC to the list of channels to scan to find a valid network.
3. If SC or ID is changed from the default, apply changes (make SC and ID changes take effect)
by issuing the AC or CN command.
4. The Associate LED will start blinking once the router has joined a PAN.
5. If the Associate LED is not blinking, the AI command can be read to determine the cause of join
failure.
6. Once the router has joined, the OP and CH commands will indicate the operating 64-bit PAN ID
and channel the router joined.
7. The MY command will reflect the 16-bit address the router received when it joined.
8. The API Modem Status frame ("Associated") is sent out the serial port when using API mode.
9. The joined router will allow other devices to join for a time based on its NJ setting.
End Device Operation
Similar to routers, end devices must also discover and join a valid ZigBee network before they can participate in a
network. After an end device has joined a network, it can communicate with other devices on the network. Since
end devices are intended to be battery powered and therefore support low power (sleep) modes, end devices cannot
allow other devices to join, nor can they route data packets.
Discovering ZigBee Networks
End devices go through the same process as routers to discover networks by issuing a PAN scan. After sending
the broadcast beacon request transmission, the end device listens for a short time in order to receive beacons
sent by nearby routers and coordinators on the same channel. The end device evaluates each beacon received
on the channel to determine if a valid PAN is found. An end device considers a PAN to be valid if the PAN:
•Has a valid 64-bit PAN ID (PAN ID matches ID if ID > 0)
•Has the correct stack profile (ZS command)
•Is allowing joining
•Has capacity for additional end devices (see End Device Capacity section below).
If a valid PAN is not found, the end device performs the PAN scan on the next channel in its scan channels list
and continues this process until a valid network is found, or until all channels have been scanned. If all channels
have been scanned and a valid PAN was not discovered, the end device may enter a low power sleep state and
scan again later.
If scanning all SC channels fails to discover a valid PAN, XBee ZB modules will attempt to enter a low power
state and will retry scanning all SC channels after the module wakes from sleeping. If the module cannot enter
a low power state, it will retry scanning all channels, similar to the router. To meet ZigBee Alliance
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requirements, the end device will attempt up to 9 scans per minute for the first 5 minutes, and 3 scans per
minute thereafter.
Note: The XBee ZB end device will not enter sleep until it has completed scanning all SC channels for a valid
network.
Joining a Network
Once the end device discovers a valid network, it joins the network, similar to a router, by sending an
association request (to the device that sent a valid beacon) to request a join on the ZigBee network. The device
allowing the join then sends an association response frame that either allows or denies the join.
When an end device joins a network, it receives a 16-bit address from the device that allowed the join. The 16bit address is randomly selected by the device that allowed the join.
Parent Child Relationship
Since an end device may enter low power sleep modes and not be immediately responsive, the end device relies
on the device that allowed the join to receive and buffer incoming messages in its behalf until it is able to wake
and receive those messages. The device that allowed an end device to join becomes the parent of the end
device, and the end device becomes a child of the device that allowed the join.
End Device Capacity
Routers and coordinators maintain a table of all child devices that have joined called the child table. This table is
a finite size and determines how many end devices can join. If a router or coordinator has at least one unused
entry in its child table, the device is said to have end device capacity. In other words, it can allow one or more
additional end devices to join. ZigBee networks should have sufficient routers to ensure adequate end device
capacity.
The initial release of software on this platform supports up to 20 end devices when configured as a coordinator
or a router.
In ZB firmware, the NC command (number of remaining end device children) can be used to determine how
many additional end devices can join a router or coordinator. If NC returns 0, then the router or coordinator
device has no more end device capacity. (Its child table is full.)
Also of note, since routers cannot sleep, there is no equivalent need for routers or coordinators to track joined
routers. Therefore, there is no limit to the number of routers that can join a given router or coordinator device.
(There is no "router capacity" metric.)
Authentication
In a network where security is enabled, the end device must then go through an authentication process. See
chapter 5 for a discussion on security and authentication.
Persistent Data
The end device can retain its PAN ID, operating channel, and security policy information through a power cycle.
However, since end devices rely heavily on a parent, the end device does an orphan scan to try and contact its
parent. If the end device does not receive an orphan scan response (called a coordinator realignment
command), it will leave the network and try to discover and join a new network. When the end device leaves a
network, the previous PAN ID and operating channel settings are lost.
Orphan Scans
When an end device comes up from a power cycle, it performs an orphan scan to verify it still has a valid parent.
The orphan scan is sent as a broadcast transmission and contains the 64-bit address of the end device. Nearby
routers and coordinator devices that receive the broadcast check their child tables for an entry that contains the
end device's 64-bit address. If an entry is found with a matching 64-bit address, the device sends a coordinator
realignment command to the end device that includes the end device's 16-bit address, 16-bit PAN ID, operating
channel, and the parent's 64-bit and 16-bit addresses.
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If the orphaned end device receives a coordinator realignment command, it is considered joined to the network.
Otherwise, it will attempt to discover and join a valid network.
XBee ZigBee End Device Joining
When an end device is powered on, if it is not joined to a valid ZigBee network, or if the orphan scan fails to find
a parent, it immediately attempts to find and join a valid ZigBee network.
Note: The DJ command can be set to 1 to disable joining. The DJ parameter cannot be written with WR, so a
power cycle always clears the DJ setting.
Similar to a router, the following commands control the end device joining process.
Network joining commands used by an end device to join a network.
Command
Description
ID
Sets the 64-bit PAN ID to join. Setting ID=0 allows the router to join any
64-bit PAN ID.
SC
Set the scan channels bitmask that determines which channels an end
device will scan to find a valid network. SC on the end device should be
set to match SC on the coordinator and routers in the desired network.
For example, setting SC to 0x281 enables scanning on channels 0x0B,
0x12, and 0x14, in that order.
SD
Set the scan duration, or time that the end device will listen for beacons
on each channel.
ZS
Set the stack profile on the device.
EE
Enable or disable security in the network. This must be set to match the
EE value (security policy) of the coordinator.
KY
Set the trust center link key. If set to 0 (default), the link key is expected to
be obtained (unencrypted) during joining.
Once the end device joins a network, the network configuration settings can persist through power cycles as
mentioned in the "Persistent Data" section previously. If joining fails, the status of the last join attempt can be
read in the AI command register.
If any of these command values changes, when command register changes are applied, the end device will
leave its current network and attempt to discover and join a new valid network.
When a ZB end device has successfully started a network, it
• Sets AI=0
• Starts blinking the Associate LED
• Sends an API modem status frame ("associated") out the serial port when using API mode
• Attempts to enter low power modes.
These behaviors are configurable using the following commands:
Command
Description
D5
Enables the Associate LED functionality.
LT
Sets the Associate LED blink time when joined. Default is 2 blinks per
second (end devices).
SM, SP, ST, SN,
SO
Parameters that configure the sleep mode characteristics. (See
Managing End Devices chapter for details.)
Parent Connectivity
The XBee ZB end device sends regular poll transmissions to its parent when it is awake. These poll
transmissions query the parent for any new received data packets. The parent always sends a MAC layer
acknowledgment back to the end device. The acknowledgment indicates whether the parent has data for the
end device or not.
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If the end device does not receive an acknowledgment for 3 consecutive poll requests, it considers itself
disconnected from its parent and will attempt to discover and join a valid ZigBee network. See "Managing End
Devices" chapter for details.
Resetting the End Device
When the end device is reset or power cycled, if the orphan scan successfully locates a parent, the end device
then checks its PAN ID, operating channel and stack profile against the network configuration settings (ID, SC,
ZS). It also verifies the saved security policy is valid based on the security configuration commands (EE, KY). If
the end device's PAN ID, operating channel, stack profile, or security policy is invalid, the end device will leave
the network and attempt to join a new network based on its network joining command values.
To prevent the end device from leaving an existing network, the WR command should be issued after all
network joining commands have been configured in order to retain these settings through power cycle or reset
events.
Leaving a Network
There are a couple of mechanisms that will cause the router to leave its current PAN and attempt to discover
and join a new network based on its network joining parameter values. These include the following:
• The ID command changes such that the current 64-bit PAN ID is invalid.
• The SC command changes such that the current operating channel (CH) is not included in the channel
mask.
• The ZS or any of the security command values change.
• The NR0 command is issued to cause the end device to leave.
• The NR1 command is issued to send a broadcast transmission, causing all devices in the network to leave
and migrate to a different channel.
• The commissioning button is pressed 4 times or the CB command is issued with a parameter of 4.
• The end device's parent is powered down or the end device is moved out of range of the parent such that
the end device fails to receive poll acknowledgment messages.
Note that changes to command values only take effect when changes are applied (AC or CN commands).
Example: Joining a Network
After starting a coordinator (that is allowing joins), the following steps will cause an XBee end device to join the
network:
1. Set ID to the desired 64-bit PAN ID, or to 0 to join any PAN.
2. Set SC to the list of channels to scan to find a valid network.
3. If SC or ID is changed from the default, apply changes (make SC and ID changes take effect)
by issuing the AC or CN command.
4. The Associate LED will start blinking once the end device has joined a PAN.
5. If the Associate LED is not blinking, the AI command can be read to determine the cause of join
failure.
6. Once the end device has joined, the OP and CH commands will indicate the operating 64-bit
PAN ID and channel the end device joined.
7. The MY command will reflect the 16-bit address the router received when it joined.
8. The API Modem Status frame ("Associated") is sent out the serial port when using API mode.
9. The joined end device will attempt to enter low power sleep modes based on its sleep
configuration commands (SM, SP, SN, ST, SO).
ZigBee Channel Scanning
As mentioned previously, routers and end devices must scan one or more channels to discover a valid network to
join. When a join attempt begins, the XBee sends a beacon request transmission on the lowest channel specified in
the SC (scan channels) command bitmask. If a valid PAN is found on the channel, the XBee will attempt to join the
PAN on that channel. Otherwise, if a valid PAN is not found on the channel, it will attempt scanning on the next
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higher channel in the SC command bitmask. The XBee will continue to scan each channel (from lowest to highest) in
the SC bitmask until a valid PAN is found or all channels have been scanned. Once all channels have been scanned,
the next join attempt will start scanning on the lowest channel specified in the SC command bitmask.
For example, if the SC command is set to 0x400F, the XBee would start scanning on channel 11 (0x0B) and scan
until a valid beacon is found, or until channels 11, 12, 13, 14, and 25 have been scanned (in that order).
Once an XBee router or end device joins a network on a given channel, if the XBee is told to leave (see "Leaving a
Network" section), it will leave the channel it joined on and continue scanning on the next higher channel in the SC
bitmask.
For example, if the SC command is set to 0x400F, and the XBee joins a PAN on channel 12 (0x0C), if the XBee
leaves the channel, it will start scanning on channel 13, followed by channels 14 and 25 if a valid network is not
found. Once all channels have been scanned, the next join attempt will start scanning on the lowest channel
specified in the SC command bitmask.
Managing Multiple ZigBee Networks
In some applications, multiple ZigBee networks may exist in proximity of each other. The application may need
provisions to ensure the XBee joins the desired network. There are a number of features in ZigBee to manage
joining among multiple networks. These include the following:
•PAN ID Filtering
•Preconfigured Security Keys
•Permit Joining
•Application Messaging
PAN ID Filtering
The XBee can be configured with a fixed PAN ID by setting the ID command to a non-zero value. If the PAN ID
is set to a non-zero value, the XBee will only join a network with the same PAN ID.
Pre-configured Security Keys
Similar to PAN ID filtering, this method requires a known security key be installed on a router to ensure it will
join a ZigBee network with the same security key. If the security key (KY command) is set to a non-zero value,
and if security is enabled (EE command), an XBee router or end device will only join a network with the same
security key.
Permit Joining
The Permit Joining parameter can be disabled in a network to prevent unwanted devices from joining. When a
new device must be added to a network, permit-joining can be enabled for a short time on the desired network.
In the XBee firmware, joining is disabled by setting the NJ command to a value less than 0xFF on all routers and
coordinator devices. Joining can be enabled for a short time using the commissioning push-button (see Network
Commissioning chapter for details) or the CB command.
Application Messaging
If the above mechanisms are not feasible, the application could build in a messaging framework between the
coordinator and devices that join its network. For example, the application code in joining devices could send a
transmission to the coordinator after joining a network, and wait to receive a defined reply message. If the
application does not receive the expected response message after joining, the application could force the XBee
to leave and continue scanning (see NR parameter).
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4. Transmission, Addressing, and Routing
Addressing
All ZigBee devices have two different addresses, a 64-bit and a 16-bit address. The characteristics of each are
described below.
64-bit Device Addresses
The 64-bit address is a unique device address assigned during manufacturing. This address is unique to each
physical device. The 64-bit address includes a 3-byte Organizationally Unique Identifier (OUI) assigned by the
IEEE. The 64-bit address is also called the extended address.
16-bit Device Addresses
A device receives a 16-bit address when it joins a ZigBee network. For this reason, the 16-bit address is also
called the "network address". The 16-bit address of 0x0000 is reserved for the coordinator. All other devices
receive a randomly generated address from the router or coordinator device that allows the join. The 16-bit
address can change under certain conditions:
• An address conflict is detected where two devices are found to have the same 16-bit address
• A device leaves the network and later joins (it can receive a different address)
All ZigBee transmissions are sent using the source and destination 16-bit addresses. The routing tables on
ZigBee devices also use 16-bit addresses to determine how to route data packets through the network.
However, since the 16-bit address is not static, it is not a reliable way to identify a device.
To solve this problem, the 64-bit destination address is often included in data transmissions to guarantee data is
delivered to the correct destination. The ZigBee stack can discover the 16-bit address, if unknown, before
transmitting data to a remote.
Application Layer Addressing
ZigBee devices can support multiple application profiles, cluster IDs, and endpoints. (See "ZigBee Application
Layers - In Depth" in chapter 3.) Application layer addressing allows data transmissions to be addressed to
specific profile IDs, cluster IDs, and endpoints. Application layer addressing is useful if an application must
• Interoperate with other ZigBee devices outside of the Digi application profile
• Utilize service and network management capabilities of the ZDO
• Operate on a public application profile such as Home Controls or Smart Energy.
API mode provides a simple yet powerful interface that can easily send data to any profile ID, endpoint, and
cluster ID combination on any device in a ZigBee network.
Data Transmission
ZigBee data packets can be sent as either unicast or broadcast transmissions. Unicast transmissions route data from
one source device to one destination device, whereas broadcast transmissions are sent to many or all devices in the
network.
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Broadcast Transmissions
Broadcast transmissions within the ZigBee protocol are intended to be propagated throughout the entire
network such that all nodes receive the transmission. To accomplish this, the coordinator and all routers that
receive a broadcast transmission will retransmit the packet three times.
Note: when a router or coordinator delivers a broadcast transmission to an end device child, the transmission is only sent
once (immediately after the end device wakes and polls the parent for any new data). See Parent Operation section in
chapter 6 for details.
Broadcast Data Transmission
Legend
C=Coordinator
R=Router
E=End Device
Each node that transmits the broadcast will also create an entry in a local broadcast transmission table. This
entry is used to keep track of each received broadcast packet to ensure the packets are not endlessly
transmitted. Each entry persists for 8 seconds. The broadcast transmission table holds 8 entries.
For each broadcast transmission, the ZigBee stack must reserve buffer space for a copy of the data packet. This
copy is used to retransmit the packet as needed. Large broadcast packets will require more buffer space. This
information on buffer space is provided for general knowledge; the user does not and cannot change any buffer
spacing. Buffer spacing is handled automatically by the XBee module.
Since broadcast transmissions are retransmitted by each device in the network, broadcast messages should be
used sparingly.
Unicast Transmissions
Unicast transmissions are sent from one source device to another destination device. The destination device
could be an immediate neighbor of the source, or it could be several hops away. Unicast transmissions that are
sent along a multiple hop path require some means of establishing a route to the destination device. See the
"RF Packet Routing" section in chapter 4 for details.
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Address Resolution
As mentioned previously, each device in a ZigBee network has both a 16-bit (network) address and a 64-bit
(extended) address. The 64-bit address is unique and assigned to the device during manufacturing, and the
16-bit address is obtained after joining a network. The 16-bit address can also change under certain
conditions.
When sending a unicast transmission, the ZigBee network layer uses the 16-bit address of the destination
and each hop to route the data packet. If the 16-bit address of the destination is not known, the ZigBee
stack includes a discovery provision to automatically discover the destination device's 16-bit address before
routing the data.
To discover a 16-bit address of a remote, the device initiating the discovery sends a broadcast address
discovery transmission. The address discovery broadcast includes the 64-bit address of the remote device
whose 16-bit address is being requested. All nodes that receive this transmission check the 64-bit address
in the payload and compare it to their own 64-bit address. If the addresses match, the device sends a
response packet back to the initiator. This response includes the remote's 16-bit address. When the
discovery response is received, the initiator will then transmit the data.
Address Table
Each ZigBee device maintains an address table that maps a 64-bit address to a 16-bit address. When a
transmission is addressed to a 64-bit address, the ZigBee stack searches the address table for an entry
with a matching 64-bit address, in hopes of determining the destination's 16-bit address. If a known 16-bit
address is not found, the ZigBee stack will perform address discovery to discover the device's current 16bit address.
Sample Address Table
64-bit Address
16-bit Address
0013 A200 4000 0001 0x4414
0013 A200 400A 3568 0x1234
0013 A200 4004 1122
0xC200
0013 A200 4002 1123
0xFFFE (unknown)
The XBee modules can store up to 10 address table entries. For applications where a single device (e.g.
coordinator) may send unicast transmissions to more than 10 devices, the application should implement an
address table to store the 16-bit and 64-bit addresses for each remote device. Any XBee that will send data
to more than 10 remotes should also use API mode. The application can then send both the 16-bit and 64bit addresses to the XBee in the API transmit frames which will significantly reduce the number of 16-bit
address discoveries and greatly improve data throughput.
If an application will support an address table, the size should ideally be larger than the maximum number
of destination addresses the device will communicate with. Each entry in the address table should contain a
64-bit destination address and its last known 16-bit address.
When sending a transmission to a destination 64-bit address, the application should search the address
table for a matching 64-bit address. If a match is found, the 16-bit address should be populated into the
16-bit address field of the API frame. If a match is not found, the 16-bit address should be set to 0xFFFE
(unknown) in the API transmit frame.
The API provides indication of a remote device's 16-bit address in the following frames:
• All receive data frames
Rx Data (0x90)
Rx Explicit Data (0x91)
I/O Sample Data (0x92)
Node Identification Indicator (0x95)
Route Record Indicator (0xA1)
etc.
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• Transmit status frame (0x8B)
Group Table
Each router and the coordinator maintain a persistent group table. Each entry contains an endpoint value,
a two byte group ID, and an optional name string of zero to 16 ASCII characters, and an index into the
binding table. More than one endpoint may be associated with a group ID, and more than one group ID
may be associated with a given endpoint. The capacity of the group table is 16 entries.
The application should always update the 16-bit address in the address table when one of these frames is
received to ensure the table has the most recently known 16-bit address. If a transmission failure occurs,
the application should set the 16-bit address in the table to 0xFFFE (unknown).
Binding Transmissions
Binding transmissions use indirect addressing to send one or more messages to other destination devices. An
Explicit Addressing ZigBee Command Frame (0x11) using the Indirect Tx Option (0x04) is treated as a binding
transmission request.
Address Resolution
The source endpoint and cluster ID values of a binding transmission are used as keys to lookup matching
binding table entries. For each matching binding table entry, the type field of the entry indicates whether a
unicast or a multicast message should be sent.
In the case of a unicast entry, the transmission request is updated with the Destination Endpoint and MAC
Address, and unicast to its destination. In the case of a multicast entry, the message is updated using the
two least significant bytes of the Destination MAC Address as the groupID, and multicast to its
destination(s).
Binding Table
Each router and the coordinator maintain a persistent binding table to map source endpoint and cluster ID
values into 64 bit destination address and endpoint values. The capacity of the binding table is 16 entries.
Multicast Transmissions
Multicast transmissions are used to broadcast a message to destination devices which have active endpoints
associated with a common group ID. An explicit transmit request frame (0x11) using the Multicast Tx Option
(0x08) is treated as a multicast transmission request.
Address Resolution
The 64 bit destination address value does not matter and it is recommended it be set to
0xFFFFFFFFFFFFFFFF. The 16 bit destination address value should be set to the destination groupID.
Fragmentation
Each unicast transmission may support up to 84 bytes of RF payload. (Enabling security or using source
routing can reduce this number. See the NP command for details.) However, the XBee ZB firmware supports
a ZigBee feature called fragmentation that allows a single large data packet to be broken up into multiple
RF transmissions and reassembled by the receiver before sending data out its serial port. This is shown in
the image below.
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The transmit frame can include up to 255 bytes of data, which will be broken up into multiple transmissions
and reassembled on the receiving side. If one or more of the fragmented messages are not received by the
receiving device, the receiver will drop the entire message, and the sender will indicate a transmission
failure in the Tx Status API frame.
Applications that do not wish to use fragmentation should avoid sending more than the maximum number
of bytes in a single RF transmission. See the "Maximum RF Payload Size" section for details.
If RTS flow control is enabled on the receiving module (using the D6 command) and a fragmented message
is received, then RTS flow control will be ignored.
Note: Broadcast transmissions do not support fragmentation. Maximum payload size = up to 84 bytes.
Data Transmission Examples
AT Firmware
To send a data packet in transparent mode, the DH and DL commands must be set to match the 64-bit
address of the destination device. DH must match the upper 4-bytes, and DL must match the lower 4
bytes. Since the coordinator always receives a 16-bit address of 0x0000, a 64-bit address of
0x0000000000000000 is defined as the coordinator's address (in ZB firmware). The default values of DH
and DL are 0x00, which sends data to the coordinator.
Example 1: Send a transmission to the coordinator.
(In this example, a '\r' refers to a carriage return character.)
A router or end device can send data in two ways. First, set the destination address (DH and DL
commands) to 0x00.
1. Enter command mode ('+++')
2. After receiving an OK\r, issue the following commands:
a. ATDH0\r
b. ATDL0\r
c. ATCN\r
3. Verify that each of the 3 commands returned an OK\r response.
4. After setting these command values, all serial characters will be sent as a unicast transmission
to the coordinator.
Alternatively, if the coordinator's 64-bit address is known, DH and DL can be set to the coordinator's 64-bit
address. Suppose the coordinator's address is 0x0013A200404A2244.
1. Enter command mode ('+++')
2. After receiving an OK\r, issue the following commands:
a. ATDH13A200\r
b. ATDL404A2244\
c. ATCN\r
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3. Verify that each of the 3 commands returned an OK\r response.
4. After setting these command values, all serial characters will be sent as a unicast transmission
to the coordinator.
API Firmware
Use the transmit request, or explicit transmit request frame (0x10 and 0x11 respectively) to send data to
the coordinator. The 64-bit address can either be set to 0x0000000000000000, or to the 64-bit address of
the coordinator. The 16-bit address should be set to 0xFFFE when using the 64-bit address of all 0x00s.
To send an ascii "1" to the coordinator's 0x00 address, the following API frame can be used:
7E 00 0F 10 01 0000 0000 0000 0000 FFFE 00 00 31 C0
If the explicit transmit frame is used, the cluster ID should be set to 0x0011, the profile ID to 0xC105, and
the source and destination endpoints to 0xE8 (recommended defaults for data transmissions in the Digi
profile.) The same transmission could be sent using the following explicit transmit frame:
7E 00 15 11 01 0000 0000 0000 0000 FFFE E8 E8 0011 C105 00 00 31 18
Notice the 16-bit address is set to 0xFFFE. This is required when sending to a 64-bit address of 0x00s.
Now suppose the coordinator's 64-bit address is 0x0013A200404A2244. The following transmit request API
frame (0x10) will send an ASCII "1" to the coordinator:
7E 00 0F 10 01 0013 A200 404A 2244 0000 0000 31 18
Example 2: Send a broadcast transmission.
(In this example, a '\r' refers to a carriage return character.)
Perform the following steps to configure a broadcast transmission:
1. Enter command mode ('+++')
2. After receiving an OK\r, issue the following commands:
a. ATDH0\r
b. ATDLffff\r
c. ATCN\r
3. Verify that each of the 3 commands returned an OK\r response
4. After setting these command values, all serial characters will be sent as a broadcast
transmission.
API Firmware
This example will use the transmit request API frame (0x10) to send an ASCII "1" in a broadcast
transmission.
To send an ascii "1" as a broadcast transmission, the following API frame can be used:
7E 00 0F 10 01 0000 0000 0000 FFFF FFFE 00 00 31 C2
Notice the destination 16-bit address is set to 0xFFFE for broadcast transmissions.
Example 3: Send an indirect (binding) transmission.
This example will use the explicit transmit request frame (0x11) to send a transmission using indirect
addressing through the binding table. It assumes the binding table has already been set up to map a source
endpoint of 0xE7 and cluster ID of 0x0011 to a destination endpoint and 64 bit destination address. The
message data is a manufacturing specific profile message using profile ID 0xC105, command ID 0x00, a
ZCL Header of 151E10, transaction number EE, and a ZCL payload of 000102030405.
7E 001E 11 e4 FFFFFFFFFFFFFFFF FFFE E7 FF 0011 C105 00 04 151E10EE000102030405 14
Note: The 64 bit destination address has been set to all 0xFF values, and the destination endpoint set to 0xFF. The Tx
Option 0x04 indicates indirect addressing is to be used. The 64 bit destination address and destination endpoint will be
filled in by looking up data associated with binding table entries which match Example 5: Send a multicast (group ID)
broadcast.
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Example 4: Send a multicast (group ID) broadcast.
This example will use the explicit transmit request frame (0x11) to send a transmission using multicasting.
It assumes the destination devices already have their group tables set up to associate an active endpoint
with the group ID (0x1234) of the multicast transmission. The message data is a manufacturing specific
profile message using profile ID 0xC105, command ID 0x00, a ZCL Header of 151E10, transaction number
EE, and a ZCL payload of 000102030405.
7E 001E 11 01 FFFFFFFFFFFFFFFF 1234 E6 FE 0001 C105 00 08 151E10EE000102030405 BC
Note: The 64 bit destination address has been set to all 0xFF values, and the destination endpoint set to 0xFE. The Tx
Option 0x08 indicates multicast (group) addressing is to be used.
RF Packet Routing
Unicast transmissions may require some type of routing. ZigBee includes several different ways to route data, each
with its own advantages and disadvantages. These are summarized in the table below.
Routing Approach Description
When to Use
Ad hoc On-demand
Routing paths are created between source and Use in networks that will not scale beyond about
Distance Vector (AODV) destination, possibly traversing multiple nodes 40 destination devices.
Mesh Routing
(“hops”). Each device knows who to send data
to next to eventually reach the destination
Many-to-One Routing
A single broadcast transmission configures
Useful when many remote devices must send
reverse routes on all devices into the device that data to a single gateway or collector device.
sends the broadcast
Source Routing
Data packets include the entire route the packet Improves routing efficiency in large networks
should traverse to get from source to
(over 40 remote devices)
destination
Note – End devices do not make use of these routing protocols. Rather, an end device sends a unicast transmission to its
parent and allows the parent to route the data packet in its behalf.
Note - A network cannot revert from Many-to-One routing to AODV routing without first doing a network reset (NR).
Link Status Transmission
Before discussing the various routing protocols, it is worth understanding the primary mechanism in ZigBee for
establishing reliable bi-directional links. This mechanism is especially useful in networks that may have a
mixture of devices with varying output power and/or receiver sensitivity levels.
Each coordinator or router device periodically sends a link status message. This message is sent as a 1-hop
broadcast transmission, received only by one-hop neighbors. The link status message contains a list of
neighboring devices and incoming and outgoing link qualities for each neighbor. Using these messages,
neighboring devices can determine the quality of a bi-directional link with each neighbor and use that
information to select a route that works well in both directions.
For example, consider a network of two neighboring devices that send periodic link status messages. Suppose
that the output power of device A is +18dBm, and the output power of device B is +3dBm (considerably less
than the output power of device A). The link status messages might indicate the following:
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This mechanism enables devices A and B to recognize that the link is not reliable in both directions and select a
different neighbor when establishing routes. (Such links are called asymmetric links, meaning the link quality is
not similar in both directions.)
When a router or coordinator device powers on, it sends link status messages every couple seconds to attempt
to discover link qualities with its neighbors quickly. After being powered on for some time, the link status
messages are sent at a much slower rate (about every 3-4 times per minute).
AODV Mesh Routing
ZigBee employs mesh routing to establish a route between the source device and the destination. Mesh routing
allows data packets to traverse multiple nodes (hops) in a network to route data from a source to a destination.
Routers and coordinators can participate in establishing routes between source and destination devices using a
process called route discovery. The Route discovery process is based on the AODV (Ad-hoc On-demand Distance
Vector routing) protocol.
Sample Transmission Through a Mesh Network
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AODV (Ad-hoc On-demand Distance Vector) Routing Algorithm
Routing under the AODV protocol is accomplished using tables in each node that store the next hop
(intermediary node between source and destination nodes) for a destination node. If a next hop is not known,
route discovery must take place in order to find a path. Since only a limited number of routes can be stored on
a Router, route discovery will take place more often on a large network with communication between many
different nodes.
Node
R3
R5
Destination Address
Next Hop Address
Router 6
Coordinator
Router 6
Router 5
Router 6
Router 6
When a source node must discover a route to a destination node, it sends a broadcast route request command.
The route request command contains the source network address, the destination network address and a path
cost field (a metric for measuring route quality). As the route request command is propagated through the
network (refer to the Broadcast Transmission), each node that re-broadcasts the message updates the path
cost field and creates a temporary entry in its route discovery table.
Sample Route Request (Broadcast) Transmission Where R3 is Trying to Discover a Route to R6
When the destination node receives a route request, it compares the ‘path cost’ field against previously received
route request commands. If the path cost stored in the route request is better than any previously received, the
destination node will transmit a route reply packet to the node that originated the route request. Intermediate
nodes receive and forward the route reply packet to the source node (the node that originated route request).
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Sample Route Reply (Unicast) Where R6 Sends a Route Reply to R3.
Note: R6 could send multiple replies if it identifies a better route.
Retries and Acknowledgments
ZigBee includes acknowledgment packets at both the Mac and Application Support (APS) layers. When data is
transmitted to a remote device, it may traverse multiple hops to reach the destination. As data is transmitted
from one node to its neighbor, an acknowledgment packet (Ack) is transmitted in the opposite direction to
indicate that the transmission was successfully received. If the Ack is not received, the transmitting device will
retransmit the data, up to 4 times. This Ack is called the Mac layer acknowledgment.
In addition, the device that originated the transmission expects to receive an acknowledgment packet (Ack)
from the destination device. This Ack will traverse the same path that the data traversed, but in the opposite
direction. If the originator fails to receive this Ack, it will retransmit the data, up to 2 times until an Ack is
received. This Ack is called the ZigBee APS layer acknowledgment.
Refer to the ZigBee specification for more details.
Many-to-One Routing
In networks where many devices must send data to a central collector or gateway device, AODV mesh routing
requires significant overhead. If every device in the network had to discover a route before it could send data to
the data collector, the network could easily become inundated with broadcast route discovery messages.
Many-to-one routing is an optimization for these kinds of networks. Rather than require each device to do its
own route discovery, a single many-to-one broadcast transmission is sent from the data collector to establish
reverse routes on all devices. This is shown in the figure below. The left side shows the many broadcasts the
devices can send when they create their own routes and the route replies generated by the data collector. The
right side shows the benefits of many-to-one routing where a single broadcast creates reverse routes to the
data collector on all routers.
The many-to-one broadcast is a route request message with the target discovery address set to the address of
the data collector. Devices that receive this route request create a reverse many-to-one routing table entry to
create a path back to the data collector. The ZigBee stack on a device uses historical link quality information
about each neighbor to select a reliable neighbor for the reverse route.
When a device sends data to a data collector, and it finds a many-to-one route in its routing table, it will
transmit the data without performing a route discovery. The many-to-one route request should be sent
periodically to update and refresh the reverse routes in the network.
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Applications that require multiple data collectors can also use many-to-one routing. If more than one data
collector device sends a many-to-one broadcast, devices will create one reverse routing table entry for each
collector.
In ZB firmware, the AR command is used to enable many-to-one broadcasting on a device. The AR command
sets a time interval (measured in 10 second units) for sending the many to one broadcast transmission. (See
the command table for details.)
Source Routing
In applications where a device must transmit data to many remotes, AODV routing would require performing
one route discovery for each destination device to establish a route. If there are more destination devices than
there are routing table entries, established AODV routes would be overwritten with new routes, causing route
discoveries to occur more regularly. This could result in larger packet delays and poor network performance.
ZigBee source routing helps solve these problems. In contrast to many-to-one routing that establishes routing
paths from many devices to one data collector, source routing allows the collector to store and specify routes for
many remotes.
To use source routing, a device must use the API mode, and it must send periodic many-to-one route request
broadcasts (AR command) to create a many-to-one route to it on all devices. When remote devices send RF
data using a many-to-one route, they first send a route record transmission. The route record transmission is
unicast along the many-to-one route until it reaches the data collector. As the route record traverses the manyto-one route, it appends the 16-bit address of each device in the route into the RF payload. When the route
record reaches the data collector, it contains the address of the sender, and the 16-bit address of each hop in
the route. The data collector can store the routing information and retrieve it later to send a source routed
packet to the remote. This is shown in the images below.
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The data collector sends a
Many-to-One route request
broadcast to create reverse
routes on all devices.
A remote
device sends an RF data packet to the
data collector. (This is prefaced by a
route record transmission to the data
collector.)
After
obtaining a source route, the data
collector sends a source routed
transmission to the remote device.
Acquiring Source Routes
Acquiring source routes requires the remote devices to send a unicast to a data collector (device that sends
many-to-one route request broadcasts). There are several ways to force remotes to send route record
transmissions.
1. If the application on remote devices periodically sends data to the data collector, each transmission will
force a route record to occur.
2. The data collector can issue a network discovery command (ND command) to force all XBee devices to
send a network discovery response. Each network discovery response will be prefaced by a route record.
3. Periodic IO sampling can be enabled on remotes to force them to send data at a regular rate. Each IO
sample would be prefaced by a route record. (See chapter 8 for details.)
4. If the NI string of the remote device is known, the DN command can be issued with the NI string of the
remote in the payload. The remote device with a matching NI string would send a route record and a DN
response.
Storing Source Routes
When a data collector receives a route record, it sends it out the serial port as a Route Record Indicator API
frame (0xA1). To use source routing, the application should receive these frames and store the source
route information.
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Sending a Source Routed Transmission
To send a source routed transmission, the application should send a Create Source Route API frame (0x21)
to the XBee to create a source route in its internal source route table. After sending the Create Source
Route API frame, the application can send data transmission or remote command request frames as needed
to the same destination, or any destination in the source route. Once data must be sent to a new
destination (a destination not included in the last source route), the application should first send a new
Create Source Route API frame. The XBee can buffer one source route that includes up to 11 hops
(excluding source and destination).
For example, suppose a network exists with a coordinator and 5 routers (R1, R2, R3, R4, R5) with known
source routes as shown below.
To send a source-routed packet to R3, the application must send a Create Source Route API frame (0x21)
to the XBee, with a destination of R3, and 2 hops (R1 and R2). If the 64- bit address of R3 is 0x0013A200
404a1234 and the 16-bit addresses of R1, R2, and R3 are:
Device 16-bit address
R1
0xAABB
R2
0xCCDD
R3
0xEEFF
Then the Create Source Route API frame would be:
7E 0012 21 00 0013A200 404A1234 EEFF 00 02 CCDD AABB 5C
Where:
0x0012 - length
0x21 - API ID (create source route)
0x00 - frame ID (set to 0 always)
0x0013A200 404A1234 - 64-bit address of R3 (destination)
0xEEFF - 16-bit address of R3 (destination)
0x00 - Route options (set to 0)
0x02 - Number of intermediate devices in the source route
0xCCDD - Address of furthest device (1-hop from target)
0xAABB - Address of next-closer device
0x5C - Checksum (0xFF - SUM (all bytes after length))
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Repairing Source Routes
It is possible in a network to have an existing source route fail (i.e. a device in the route moves or goes
down, etc.). If a device goes down in a source routed network, all routes that used the device will be
broken.
As mentioned previously, source routing must be used with many-to-one routing. (A device that uses
source routing must also send a periodic many-to-one broadcast in order to keep routes fresh). If a source
route is broken, remote devices must send in new route record transmissions to the data collector to
provide it with a new source route. This requires that remote devices periodically send data transmissions
into the data collector. See the earlier "Acquiring Source Routes" section for details.
Retries and Acknowledgments
ZigBee includes acknowledgment packets at both the Mac and Application Support (APS) layers. When data
is transmitted to a remote device, it may traverse multiple hops to reach the destination. As data is
transmitted from one node to its neighbor, an acknowledgment packet (Ack) is transmitted in the opposite
direction to indicate that the transmission was successfully received. If the Ack is not received, the
transmitting device will retransmit the data, up to 4 times. This Ack is called the Mac layer
acknowledgment.
In addition, the device that originated the transmission expects to receive an acknowledgment packet (Ack)
from the destination device. This Ack will traverse the same path that the data traversed, but in the
opposite direction. If the originator fails to receive this Ack, it will retransmit the data, up to 2 times until an
Ack is received. This Ack is called the ZigBee APS layer acknowledgment.
Refer to the ZigBee specification for more details.
Encrypted Transmissions
Encrypted transmissions are routed similar to non-encrypted transmissions with one exception. As an encrypted
packet propagates from one device to another, each device decrypts the packet using the network key, and
authenticates the packet by verifying packet integrity. It then re-encrypts the packet with its own source address
and frame counter values, and sends the message to the next hop. This process adds some overhead latency to
unicast transmissions, but it helps prevent replay attacks. See chapter 5 for details.
Maximum RF Payload Size
XBee ZB firmware includes a command (ATNP) that returns the maximum number of RF payload bytes that can be
sent in a unicast transmission. Querying the NP command, like most other commands, returns a hexadecimal value.
This number will change based on whether security is enabled or not. If security is enabled (EE command), the
maximum number of RF payload bytes decreases since security requires additional overhead.
After reading the NP value, the following conditions can affect the maximum number of data bytes in a single RF
transmission:
•Broadcast transmissions can support 8 bytes more than unicast transmissions.
•If source routing is used, the 16-bit addresses in the source route are inserted into the RF payload space. For
example, if NP returns 84 bytes, and a source route must traverse 3 intermediate hops (3 16-bit addresses),
the total number of bytes that can be sent in one RF packet is 78.
•Enabling APS encryption (API tx option bit set) will reduce the number of payload bytes by 4.
Note: Broadcast transmissions do not support fragmentation. Maximum payload size = up to 84 bytes.
Throughput
Throughput in a ZigBee network can vary by a number of variables, including: number of hops, encryption enabled/
disabled, sleeping end devices, failures/route discoveries. Our empirical testing showed the following throughput
performance in a robust operating environment (low interference).
Data Throughput*
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Configuration
Data Throughput
1 hop, RR, SD
58kbps
1 hop, RR, SE
34kbps
1 hop, RE, SD
Not yet available
1 hop, RE, SE
Not yet available
1 hop, ER, SD
Not yet available
1 hop, ER, SE
Not yet available
4 hops, RR, SD
Not yet available
4 hops, RR, SE
Not yet available
RR = router to router,
RE = router to end device (non-sleeping),
ER = end device (non-sleeping) to router,
SD = security disabled,
SE = security enabled.
4 hops = 5 nodes total, 3 intermediate router nodes
* Data throughput measurements were made setting the serial interface rate to 115200 bps, and measuring the
time to send 100,000 bytes from source to destination. During the test, no route discoveries or failures occurred.
Latency Timing Specifications
Timing Specifications
Network Depth
100 Node Network
200 Node Network
1-byte packet:
32-byte packet:
1-byte packet:
32-byte packet:
1-byte packet:
32-byte packet:
1-byte packet:
32-byte packet:
1-byte packet:
32-byte packet:
1-byte packet:
32-byte packet:
ZDO Transmissions
ZigBee defines a ZigBee Device Objects layer (ZDO) that can provide device and service discovery and network
management capabilities. This layer is described below.
ZigBee Device Objects (ZDO)
The ZigBee Device Objects (ZDO) is supported to some extent on all ZigBee devices. The ZDO is an endpoint
that implements services described in the ZigBee Device Profile in the ZigBee specification. Each service has an
assigned cluster ID, and most service requests have an associated response. The following table describes some
common ZDO services.
Cluster Name Cluster ID Description
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Network Address
Request
0x0000
Request a 16-bit address of the
radio with a matching 64-bit
address (required parameter).
Active Endpoints
Request
0x0005
Request a list of endpoints from a
remote device.
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LQI Request
0x0031
Request data from a neighbor table
of a remote device.
Routing Table
Request
0x0032
Request to retrieve routing table
entries from a remote device.
Network Address
Response
0x8000
Response that includes the 16-bit
address of a device.
LQI Response
0x8031
Response that includes neighbor
table data from a remote device.
Routing Table
Response
0x8032
Response that includes routing
table entry data from a remote
device.
Refer to the ZigBee specification for a detailed description of all ZigBee Device Profile services.
Sending a ZDO Command
To send a ZDO command, an explicit transmit API frame must be used and formatted correctly. The source and
destination endpoints must be set to 0, and the profile ID must be set to 0. The cluster ID must be set to match
the cluster ID of the appropriate service. For example, to send an active endpoints request, the cluster ID must
be set to 0x0005.
The first byte of payload in the API frame is an application sequence number (transaction sequence number)
that can be set to any single byte value. This same value will be used in the first byte of the ZDO response. All
remaining payload bytes must be set as required by the ZDO. All multi-byte values must be sent in little endian
byte order.
Receiving ZDO Commands and Responses
In XBee ZB firmware, ZDO commands can easily be sent using the API. In order to receive incoming ZDO
commands, receiver application addressing must be enabled with the AO command. (See examples later in this
section.) Not all incoming ZDO commands are passed up to the application.
When a ZDO message is received on endpoint 0 and profile ID 0, the cluster ID indicates the type of ZDO
message that was received. The first byte of payload is generally a sequence number that corresponds to a
sequence number of a request. The remaining bytes are set as defined by the ZDO. Similar to a ZDO request,
all multi-byte values in the response are in little endian byte order.
Example 1: Send a ZDO LQI Request to read the neighbor table contents of a remote.
Looking at the ZigBee specification, the cluster ID for an LQI Request is 0x0031, and the payload only
requires a single byte (start index). This example will send an LQI request to a remote device with a 64-bit
address of 0x0013A200 40401234. The start index will be set to 0, and the transaction sequence number
will be set to 0x76
API Frame
7E 0016 11 01 0013A200 40401234 FFFE 00 00 0031 0000 00 00 76 00 CE
0x0016 - length
0x11 - Explicit transmit request
0x01 - frame ID (set to a non-zero value to enable the transmit status message, or set to 0 to disable)
0x0013A200 40401234 - 64-bit address of the remote
0xFFFE - 16-bit address of the remote (0xFFFE = unknown). Optionally, set to the 16-bit address of the
destination if known.
0x00 - Source endpoint
0x00 - Destination endpoint
0x0031 - Cluster ID (LQI Request, or Neighbor table request)
0x0000 - Profile ID (ZigBee Device Profile)
0x00 - Broadcast radius
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0x00 - Tx Options
0x76 - Transaction sequence number
0x00 - Required payload for LQI request command
0xCE - Checksum (0xFF - SUM (all bytes after length))
Description
This API frame sends a ZDO LQI request (neighbor table request) to a remote device to obtain data from its
neighbor table. Recall that the AO command must be set correctly on an API device to enable the explicit
API receive frames in order to receive the ZDO response.
Example 2: Send a ZDO Network Address Request to discover the 16-bit address of a remote.
Looking at the ZigBee specification, the cluster ID for a network Address Request is 0x0000, and the
payload only requires the following:
[64-bit address] + [Request Type] + [Start Index]
This example will send a Network Address Request as a broadcast transmission to discover the 16-bit
address of the device with a 64-bit address of 0x0013A200 40401234. The request type and start index will
be set to 0, and the transaction sequence number will be set to 0x44
API Frame
7E 001F 11 01 00000000 0000FFFF FFFE 00 00 0000 0000 00 00 44 34124040 00A21300 00 00 33
0x001F - length
0x11 - Explicit transmit request
0x01 - frame ID (set to a non-zero value to enable the transmit status message, or set to 0 to disable)
0x00000000 0000FFFF - 64-bit address for a broadcast transmission
0xFFFE - Set to this value for a broadcast transmission.
0x00 - Source endpoint
0x00 - Destination endpoint
0x0000 - Cluster ID (Network Address Request)
0x0000 - Profile ID (ZigBee Device Profile)
0x00 - Broadcast radius
0x00 - Tx Options
0x44 - Transaction sequence number
0x34124040 00A21300 00 00 - Required payload for Network Address Request command
0x33 - Checksum (0xFF - SUM (all bytes after length))
Description
This API frame sends a broadcast ZDO Network Address Request to obtain the 16-bit address of a device
with a 64-bit address of 0x0013A200 40401234. Note the bytes for the 64-bit address were inserted in
little endian byte order. All multi-byte fields in the API payload of a ZDO command must have their data
inserted in little endian byte order. Also recall that the AO command must be set correctly on an API device
to enable the explicit API receive frames in order to receive the ZDO response.
Transmission Timeouts
The ZigBee stack includes two kinds of transmission timeouts, depending on the nature of the destination device.
For destination devices such as routers whose receiver is always on, a unicast timeout is used. The unicast timeout
estimates a timeout based on the number of unicast hops the packet should traverse to get data to the destination
device. For transmissions destined for end devices, the ZigBee stack uses an extended timeout that includes the
unicast timeout (to route data to the end device's parent), and it includes a timeout for the end device to finish
sleeping, wake, and poll the parent for data.
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The ZigBee stack includes some provisions for a device to detect if the destination is an end device or not. The
ZigBee stack uses the unicast timeout unless it knows the destination is an end device.
The XBee API includes a transmit options bit that can be set to specify if the extended timeout should be used for a
given transmission. If this bit is set, the extended timeout will be used when sending RF data to the specified
destination. To improve routing reliability, applications should set the extended timeout bit when sending data to end
devices if:
•The application sends data to 10 or more remote devices, some of which are end devices, AND
•The end devices may sleep longer than the unicast timeout
Equations for these timeouts are computed in the following sections.
Note: The timeouts in this section are worst-case timeouts and should be padded by a few hundred milliseconds.
These worst-case timeouts apply when an existing route breaks down (e.g. intermediate hop or destination device
moved).
Unicast Timeout
The unicast timeout is settable with the NH command. The actual unicast timeout is computed as ((50 * NH) +
100). The default NH value is 30 which equates to a 1.6 second timeout.
The unicast timeout includes 3 transmission attempts (1 attempt and 2 retries). The maximum total timeout is
about:
3 * ((50 * NH) + 100).
For example, if NH=30 (0x1E), the unicast timeout is about
3 * ((50 * 30) + 100), or
3 * (1500 + 100), or
3 * (1600), or
4800 ms, or
4.8 seconds.
Extended Timeout
The worst-case transmission timeout when sending data to an end device is somewhat larger than when
transmitting to a router or coordinator. As described later in chapter 6, RF data packets are actually sent to the
parent of the end device, who buffers the packet until the end device wakes to receive it. The parent will buffer
an RF data packet for up to (1.2 * SP) time.
To ensure the end device has adequate time to wake and receive the data, the extended transmission timeout
to an end device is:
(50 * NH) + (1.2 * SP)
This timeout includes the packet buffering timeout (1.2 * SP) and time to account for routing through the mesh
network (50 * NH).
If an acknowledgment is not received within this time, the sender will resend the transmission up to two more
times. With retries included, the longest transmission timeout when sending data to an end device is:
3 * ((50 * NH) + (1.2 * SP))
The SP value in both equations must be entered in millisecond units. (The SP command setting uses 10ms units
and must be converted to milliseconds to be used in this equation.)
For example, suppose a router is configured with NH=30 (0x1E) and SP=0x3E8 (10,000 ms), and that it is
either trying to send data to one of its end device children, or to a remote end device. The total extended
timeout to the end device is about:
3 * ((50 * NH) + (1.2 * SP)), or
3 * (1500 + 12000), or
3 * (13500), or
40500 ms, or
40.5 seconds.
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Transmission Examples
Example 1: Send a unicast API data transmission to the coordinator using 64-bit address 0, with payload "TxData".
API Frame
7E 0014 10 01 00000000 00000000 FFFE 00 00 54 78 44 61 74 61
AB
Field Composition
0x0014 - length
0x10 - API ID (tx data)
0x01 - frame ID (set greater than 0 to enable the tx-status response)
0x00000000 00000000 - 64-bit address of coordinator (ZB definition)
0xFFFE - Required 16-bit address if sending data to 64-bit address of 0.
0x00 - Broadcast radius (0 = max hops)
0x00 - Tx options
0x54 78 44 61 74 61 - ASCII representation of "TxData" string
0xAB - Checksum (0xFF - SUM (all bytes after length))
Description
This transmission sends the string "TxData" to the coordinator, without knowing the coordinator device's
64-bit address. A 64-bit address of 0 is defined as the coordinator in ZB firmware. If the coordinator's 64bit address was known, the 64-bit address of 0 could be replaced with the coordinator's 64-bit address, and
the 16-bit address could be set to 0.
Example 2 - Send a broadcast API data transmission that all devices can receive (including sleeping
end devices), with payload "TxData".
API Frame
7E 0014 10 01 00000000 0000FFFF FFFE 00 00 54 78 44 61 74 61
AD
Field Composition
0x0014 - length
0x10 - API ID (tx data)
0x01 - frame ID (set to a non-zero value to enable the tx-status response)
0x00000000 0000FFFF - Broadcast definition (including sleeping end devices
0xFFFE - Required 16-bit address to send broadcast transmission.
0x00 - Broadcast radius (0 = max hops)
0x00 - Tx options
0x54 78 44 61 74 61 - ASCII representation of "TxData" string
0xAD - Checksum (0xFF - SUM (all bytes after length))
Description
This transmission sends the string "TxData" as a broadcast transmission. Since the destination address is
set to 0xFFFF, all devices, including sleeping end devices can receive this broadcast.
If receiver application addressing is enabled, the XBee will report all received data frames in the explicit
format (0x91) to indicate the source and destination endpoints, cluster ID, and profile ID that each packet
was received on. (Status messages like modem status and route record indicators are not affected.)
To enable receiver application addressing, set the AO command to 1 using the AT command frame (0x08).
Here's how to do this:
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API Frame
7E 0005 08 01 414F 01 65
Field Composition
0x0005 - length
0x08 - API ID (at command)
0x01 - frame ID (set to a non-zero value to enable AT command response frames)
0x414F - ASCII representation of 'A','O' (the command being issued)
0x01 - Parameter value
0x65 - Checksum (0xFF - SUM (all bytes after length))
Description
Setting AO=1 is required for the XBee to use the explicit receive API frame (0x91) when RF data packets
are received. This is required if the application needs indication of source or destination endpoint, cluster
ID, and/or profile ID values used in received ZigBee data packets. ZDO messages can only be received if
AO=1.
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5. XBee ZigBee Security
ZigBee supports various levels of security that can be configured depending on the needs of the application. Security
provisions include:
• 128-bit AES encryption
• Two security keys that can be preconfigured or obtained during joining
• Support for a trust center
• Provisions to ensure message integrity, confidentiality, and authentication.
The first half of this chapter describes various security features defined in the ZigBee specification, while the last half
illustrates how the XBee modules can be configured to support these features
Security Modes
The ZigBee standard supports three security modes – residential, standard, and high security. Residential security
was first supported in the ZigBee 2006 standard. This level of security requires a network key be shared among
devices. Standard security adds a number of optional security enhancements over residential security, including an
APS layer link key. High security adds entity authentication, and a number of other features not widely supported.
XBee ZB modules primarily support standard security, although end devices that support residential security can join
and interoperate with standard security devices. The remainder of this chapter focuses on material that is relevant
to standard security.
ZigBee Security Model
ZigBee security is applied to the Network and APS layers. Packets are encrypted with 128-bit AES encryption. A
network key and optional link key can be used to encrypt data. Only devices with the same keys are able to
communicate together in a network. Routers and end devices that will communicate on a secure network must
obtain the correct security keys.
Network Layer Security
The network key is used to encrypt the APS layer and application data. In addition to encrypting application
messages, network security is also applied to route request and reply messages, APS commands, and ZDO
commands. Network encryption is not applied to MAC layer transmissions such as beacon transmissions, etc. If
security is enabled in a network, all data packets will be encrypted with the network key.
Packets are encrypted and authenticated using 128-bit AES. This is shown in the figure below.
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Frame Counter
The network header of encrypted packets includes a 32-bit frame counter. Each device in the network maintains
a 32-bit frame counter that is incremented for every transmission. In addition, devices track the last known 32bit frame counter for each of its neighbors. If a device receives a packet from a neighbor with a smaller frame
counter than it has previously seen, the packet is discarded. The frame counter is used to protect against replay
attacks.
If the frame counter reaches a maximum value of 0xFFFFFFFF, it does not wrap to 0 and no more transmissions
can be sent. Due to the size of the frame counters, reaching the maximum value is a very unlikely event for
most applications. The following table shows the required time under different conditions, for the frame counter
to reach its maximum value.
Average Transmission Rate Time until 32-bit frame counter expires
1 / second
136 years
10 / second
13.6 years
To clear the frame counters without compromising security, the network key can be changed in the network.
When the network key is updated, the frame counters on all devices reset to 0. (See the Network Key Updates
section for details.)
Message Integrity Code
The network header, APS header, and application data are all authenticated with 128-bit AES. A hash is
performed on these fields and is appended as a 4-byte message integrity code (MIC) to the end of the packet.
The MIC allows receiving devices to ensure the message has not been changed. The MIC provides message
integrity in the ZigBee security model. If a device receives a packet and the MIC does not match the device’s
own hash of the data, the packet is dropped.
Network Layer Encryption and Decryption
Packets with network layer encryption are encrypted and decrypted by each hop in a route. When a device
receives a packet with network encryption, it decrypts the packet and authenticates the packet. If the device is
not the destination, it then encrypts and authenticates the packet, using its own frame counter and source
address in the network header section.
Since network encryption is performed at each hop, packet latency is slightly longer in an encrypted network
than in a non-encrypted network. Also, security requires 18 bytes of overhead to include a 32-bit frame counter,
an 8-byte source address, 4-byte MIC, and 2 other bytes. This reduces the number of payload bytes that can be
sent in a data packet.
Network Key Updates
ZigBee supports a mechanism for changing the network key in a network. When the network key is changed,
the frame counters in all devices reset to 0.
APS Layer Security
APS layer security can be used to encrypt application data using a key that is shared between source and
destination devices. Where network layer security is applied to all data transmissions and is decrypted and reencrypted on a hop-by-hop basis, APS security is optional and provides end-to-end security using an APS link
key that only the source and destination device know. APS security can be applied on a packet-by-packet basis.
APS security cannot be applied to broadcast transmissions.
If APS security is enabled, packets are encrypted and authenticated using 128-bit AES. This is shown in the
figure below:
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Message integrity Code
If APS security is enabled, the APS header and data payload are authenticated with 128-bit AES. A hash is
performed on these fields and appended as a 4-byte message integrity code (MIC) to the end of the packet.
This MIC is different than the MIC appended by the network layer. The MIC allows the destination device to
ensure the message has not been changed. If the destination device receives a packet and the MIC does not
match the destination device’s own hash of the data, the packet is dropped.
APS Link Keys
There are two kinds of APS link keys – trust center link keys and application link keys. A trust center link key is
established between a device and the trust center, where an application link key is established between a device
and another device in the network where neither device is the trust center.
APS Layer Encryption and Decryption
Packets with APS layer encryption are encrypted at the source and only decrypted by the destination. Since APS
encryption requires a 5-byte header and a 4-byte MIC, the maximum data payload is reduced by 9 bytes when
APS encryption is used.
Network and APS Layer Encryption
Network and APS layer encryption can both be applied to data. The following figure demonstrates the
authentication and encryption performed on the final ZigBee packet when both are applied.
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Trust Center
ZigBee defines a trust center device that is responsible for authenticating devices that join the network. The
trust center also manages link key distribution in the network.
Forming and Joining a Secure Network
The coordinator is responsible for selecting a network encryption key. This key can either be preconfigured or
randomly selected. In addition, the coordinator generally operates as a trust center and must therefore select
the trust center link key. The trust center link key can also be preconfigured or randomly selected.
Devices that join the network must obtain the network key when they join. When a device joins a secure
network, the network and link keys can be sent to the joining device. If the joining device has a pre-configured
trust center link key, the network key will be sent to the joining device encrypted by the link key. Otherwise, if
the joining device is not pre-configured with the link key, the device could only join the network if the network
key is sent unencrypted (“in the clear”). The trust center must decide whether or not to send the network key
unencrypted to joining devices that are not pre-configured with the link key. Sending the network key
unencrypted is not recommended as it can open a security hole in the network. To maximize security, devices
should be pre-configured with the correct link key.
Implementing Security on the XBee
If security is enabled in the XBee ZB firmware, devices acquire the network key when they join a network. Data
transmissions are always encrypted with the network key, and can optionally be end-to-end encrypted with the APS
link key. The following sections discuss the security settings and options in the XBee ZB firmware.
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Enabling Security
To enable security on a device, the EE command must be set to 1. If the EE command value is changed and
changes are applied (e.g. AC command), the XBee module will leave the network (PAN ID and channel) it was
operating on, and attempt to form or join a new network.
If EE is set to 1, all data transmissions will be encrypted with the network key. When security is enabled, the
maximum number of bytes in a single RF transmission will be reduced. See the NP command for details.
Note: The EE command must be set the same on all devices in a network. Changes to the EE command should
be written to non-volatile memory (to be preserved through power cycle or reset events) using the WR
command.
Setting the Network Security Key
The coordinator must select the network security key for the network. The NK command (write-only) is used to
set the network key. If NK=0 (default), a random network key will be selected. (This should suffice for most
applications.) Otherwise, if NK is set to a non-zero value, the network security key will use the value specified
by NK. NK is only supported on the coordinator.
Routers and end devices with security enabled (ATEE=1) acquire the network key when they join a network.
They will receive the network key encrypted with the link key if they share a pre-configured link key with the
coordinator. See the following section for details.
Setting the APS Trust Center Link Key
The coordinator must also select the trust center link key, using the KY command. If KY=0 (default), the
coordinator will select a random trust center link key (not recommended). Otherwise, if KY is set greater than 0,
this value will be used as the pre-configured trust center link key. KY is write-only and cannot be read.
Note: Application link keys (sent between two devices where neither device is the coordinator) are not
supported in ZB firmware at this time.
Random Trust Center Link Keys
If the coordinator selects a random trust center link key (KY=0, default), then it will allow devices to join
the network without having a pre-configured link key. However, this will cause the network key to be sent
unencrypted over-the-air to joining devices and is not recommended.
Pre-configured Trust Center Link Keys
If the coordinator uses a pre-configured link key (KY > 0), then the coordinator will not send the network
key unencrypted to joining devices. Only devices with the correct pre-configured link key will be able to join
and communicate on the network.
Enabling APS Encryption
APS encryption is an optional layer of security that uses the link key to encrypt the data payload. Unlike network
encryption that is decrypted and encrypted on a hop-by-hop basis, APS encryption is only decrypted by the
destination device. The XBee must be configured with security enabled (EE set to 1) to use APS encryption.
APS encryption can be enabled in API mode on a per-packet basis. To enable APS encryption for a given
transmission, the "enable APS encryption" transmit options bit should be set in the API transmit frame. Enabling
APS encryption decreases the maximum payload size by 9 bytes.
Using a Trust Center
The EO command can be used to define the coordinator as a trust center. If the coordinator is a trust center, it
will be alerted to all new join attempts in the network. The trust center also has the ability to update or change
the network key on the network.
In ZB firmware, a secure network can be established with or without a trust center. Network and APS layer
encryption are supported if a trust center is used or not.
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Updating the Network Key with a Trust Center
If the trust center has started a network and the NK value is changed, the coordinator will update the
network key on all devices in the network. (Changes to NK will not force the device to leave the network.)
The network will continue to operate on the same channel and PAN ID, but the devices in the network will
update their network key, increment their network key sequence number, and restore their frame counters
to 0.
Updating the Network Key without a Trust Center
If the coordinator is not running as a trust center, the network reset command (NR1) can be used to force
all devices in the network to leave the current network and rejoin the network on another channel. When
devices leave and reform then network, the frame counters are reset to 0. This approach will cause the
coordinator to form a new network that the remaining devices should join. Resetting the network in this
manner will bring the coordinator and routers in the network down for about 10 seconds, and will likely
cause the 16-bit PAN ID and 16-bit addresses of the devices to change.
XBee Security Examples
This section covers some sample XBee configurations to support different security modes. Several AT commands are
listed with suggested parameter values. The notation in this section includes an '=' sign to indicate what each
command register should be set to - for example, EE=1. This is not the correct notation for setting command values
in the XBee. In AT command mode, each command is issued with a leading 'AT' and no '=' sign - for example ATEE1.
In the API, the two byte command is used in the command field, and parameters are populated as binary values in
the parameter field.
Example 1: Forming a network with security (pre-configured link keys)
1. Start a coordinator with the following settings:
a. ID=2234 (arbitrarily selected)
b. EE=1
c. NK=0
d. KY=4455
e. WR (save networking parameters to preserve them through power cycle)
2. Configure one or more routers or end devices with the following settings:
a. ID=2234
b. EE=1
c. KY=4455
d. WR (save networking parameters to preserve them through power cycle)
3. Read the AI setting on the coordinator and joining devices until they return 0 (formed or joined 
a network).
In this example, EE, ID, and KY are set the same on all devices. After successfully joining the secure network,
all application data transmissions will be encrypted by the network key. Since NK was set to 0 on the
coordinator, a random network key was selected. And since the link key (KY) was configured the same on all
devices, to a non-zero value, the network key was sent encrypted by the pre-configured link key (KY) when the
devices joined.
Example 2: Forming a network with security (obtaining keys during joining)
1. Start a coordinator with the following settings:
a. ID=2235
b. EE=1
c. NK=0
d. KY=0
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e. WR (save networking parameters to preserve them through power cycle)
2. Configure one or more routers or end devices with the following settings:
a. ID=2235
b. EE=1
c. KY=0
d. WR (save networking parameters to preserve them through power cycle)
3. Read the AI setting on the coordinator and joining devices until they return 0 (formed or joined
a network).
In this example, EE, ID, and KY are set the same on all devices. Since NK was set to 0 on the coordinator, a
random network key was selected. And since KY was set to 0 on all devices, the network key was sent
unencrypted ("in the clear") when the devices joined. This approach introduces a security vulnerability into the
network and is not recommended.
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6. Network Commissioning and Diagnostics
Network commissioning is the process whereby devices in a mesh network are discovered and configured for operation.
The XBee modules include several features to support device discovery and configuration. In addition to configuring
devices, a strategy must be developed to place devices to ensure reliable routes.
To accommodate these requirements, the XBee modules include various features to aid in device placement,
configuration, and network diagnostics.
Device Configuration
XBee modules can be configured locally through serial commands (AT or API), or remotely through remote API
commands. API devices can send configuration commands to set or read the configuration settings of any device in
the network.
Device Placement
For a mesh network installation to be successful, the installer must be able to determine where to place individual
XBee devices to establish reliable links throughout the mesh network.
Link Testing
A good way to measure the performance of a mesh network is to send unicast data through the network from
one device to another to determine the success rate of many transmissions. To simplify link testing, the
modules support a loopback cluster ID (0x12) on the data endpoint (0xE8). Any data sent to this cluster ID on
the data endpoint will be transmitted back to the sender. This is shown in the figure below:
The configuration steps to send data to the loopback cluster ID depend on the serial port mode as determined
by the AP command.
Transparent Mode
To send data to the loopback cluster ID on the data endpoint of a remote device, set the CI command value
to 0x12. The SE and DE commands should be set to 0xE8 (default value). The DH and DL commands should
be set to the address of the remote (0 for the coordinator, or the 64-bit address of the remote). After
exiting command mode, any received serial characters will be transmitted to the remote device, and
returned to the sender.
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API Mode
Send an Explicit Addressing ZigBee Command API frame (0x11) using 0x12 as the cluster ID and 0xE8 as
the source and destination endpoint. Data packets received by the remote will be echoed back to the
sender.
RSSI Indicators
It is possible to measure the received signal strength on a device using the DB command. DB returns the RSSI
value (measured in –dBm) of the last received packet. However, this number can be misleading. The DB value
only indicates the received signal strength of the last hop. If a transmission spans multiple hops, the DB value
provides no indication of the overall transmission path, or the quality of the worst link – it only indicates the
quality of the last link and should be used sparingly.
The DB value can be determined in hardware using the RSSI/PWM module pin (pin 6). If the RSSI PWM
functionality is enabled (P0 command), when the module receives data, the RSSI PWM is set to a value based
on the RSSI of the received packet. (Again, this value only indicates the quality of the last hop.) This pin could
potentially be connected to an LED to indicate if the link is stable or not.
Device Discovery
Network Discovery
The network discovery command can be used to discover all Digi modules that have joined a network. Issuing
the ND command sends a broadcast node discovery command throughout the network. All devices that receive
the command will send a response that includes the device’s addressing information, node identifier string (see
NI command), and other relevant information. This command is useful for generating a list of all module
addresses in a network.
When a device receives the node discovery command, it waits a random time before sending its own response.
The maximum time delay is set on the ND sender with the NT command. The ND originator includes its NT
setting in the transmission to provide a delay window for all devices in the network. Large networks may need
to increase NT to improve network discovery reliability. The default NT value is 0x3C (6 seconds).
ZDO Discovery
The ZigBee Device Profile includes provisions to discover devices in a network that are supported on all ZigBee
devices (including non-Digi products). These include the LQI Request (cluster ID 0x0031) and the Network
Update Request (cluster ID 0x0038). The LQI Request can be used to read the devices in the neighbor table of
a remote device, and the Network Update Request can be used to have a remote device do an active scan to
discover all nearby ZigBee devices. Both of these ZDO commands can be sent using the XBee Explicit API
transmit frame (0x11). See the API chapter for details. Refer to the ZigBee specification for formatting details of
these two ZDO frames.
Joining Announce
All ZigBee devices send a ZDO Device Announce broadcast transmission when they join a ZigBee network (ZDO
cluster ID 0x0013). These frames will be sent out the XBee's serial port as an Explicit Rx Indicator API frame
(0x91) if AO is set to 1. The device announce payload includes the following information:
[ Sequence Number] + [16-bit address] + [64-bit address] + [Capability]
The 16-bit and 64-bit addresses are received in little-endian byte order (LSB first). See the ZigBee specification
for details.
Commissioning Pushbutton and Associate LED
The XBee modules support a set of commissioning and LED behaviors to aid in device deployment and
commissioning. These include the commissioning pushbutton definitions and associate LED behaviors. These
features can be supported in hardware as shown below.
Commissioning Pushbutton and Associate LED Functionalities
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A pushbutton and an LED can be
connected to module pins 33 and
28 respectively to support the
commisioning pushbutton and
Associate LED functionalities.
Commissioning Pushbutton
The commissioning pushbutton definitions provide a variety of simple functions to aid in deploying devices in a
network. The commissioning button functionality on pin 33 is enabled by setting the D0 command to 1 (enabled
by default).
Button
Presses
If module is joined to a network
If module is not joined to a network
• Wakes an end device for
30 seconds
• Wakes an end device for
30 seconds
• Sends a node identification broadcast transmission
• Blinks a numeric error
code on the Associate pin
indicating the cause of
join failure (see section
6.4.2).
• Sends a broadcast transmission to enable joining
on the coordinator and all
devices in the network for
1 minute. (If joining is
permanently enabled on a
device (NJ = 0xFF), this
action has no effect on
that device.)
• N/A
• Causes the device to leave
the PAN.
• Issues ATRE to restore
module parameters to
default values, including
ID and SC.
• Issues ATRE to restore
module parameters to
default values, including
ID and SC.
• The device attempts to
join a network based on
its ID and SC settings.
• The device attempts to
join a network based on
its ID and SC settings.
Button presses may be simulated in software using the ATCB command. ATCB should be issued with a
parameter set to the number of button presses to execute. (e.g. sending ATCB1 will execute the action(s)
associated with a single button press.)
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The node identification frame is similar to the node discovery response frame – it contains the device’s address,
node identifier string (NI command), and other relevant data. All API devices that receive the node identification
frame send it out their serial port as an API Node Identification Indicator frame (0x95).
Associate LED
The Associate pin (pin 28) can provide indication of the device’s network status and diagnostics information. To
take advantage of these indications, an LED can be connected to the Associate pin as shown in the figure above.
The Associate LED functionality is enabled by setting the D5 command to 1 (enabled by default). If enabled, the
Associate pin is configured as an output and will behave as described in the following sections.
Joined Indication
The Associate pin indicates the network status of a device. If the module is not joined to a network, the
Associate pin is set high. Once the module successfully joins a network, the Associate pin blinks at a regular
time interval. This is shown in the following figure.
Joined Status of a Device
Associate
Device Not Joined
∆t
Device has joined a network
The associate pin can indicate the joined status of a device . Once the device has joined a
network, the associate pin toggles state at a regular interval (∆t). The time can be set by
using the LT command.
The LT command defines the blink time of the Associate pin. If set to 0, the device uses the default blink time
(500ms for coordinator, 250ms for routers and end devices).
Diagnostics Support
The Associate pin works with the commissioning pushbutton to provide additional diagnostics behaviors to aid in
deploying and testing a network. If the commissioning push button is pressed once, and the device has not
joined a network, the Associate pin blinks a numeric error code to indicate the cause of join failure. The number
of blinks is equal to (AI value – 0x20). For example, if AI=0x22, 2 blinks occur.
If the commissioning push button is pressed once, and the device has joined a network, the device transmits a
broadcast node identification packet. If the Associate LED functionality is enabled (D5 command), a device that
receives this transmission will blink its Associate pin rapidly for 1 second.
The following figures demonstrate these behaviors.
AI = 0x22
Associate
(D5 = 1
Device not joined)
AD0/DIO0
A single comm issioning button press when the device has not joined a network that
causes the associate pin to blink to indicate the AI Code where : AI = # blinks + 0x20.
In this example, AI = 0x22.
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Broadcast Node Identification Transmission
Associate Pin
(D5 = 1)
AD0/DIO0 Pin
(Remote Device)
A single button press on a remote device causes a broadcast node identification transmission
to be sent. All devices that receive this transmission blink their associate pin rapidly for one
second if the associate LED functionality is enabled. (D5 = 1)
Binding
There are three binding request messages supported by the Digi XBee firmware: End Device Bind, Bind, and
Unbind.
End_Device_Bind_req
The End Device Bind request (ZDO cluster 0x0020) is described in the ZigBee Specification in section
2.4.3.2.1.
During a deployment, an installer may need to bind a switch to a light. He presses a commissioning button
sequence on each device. This causes them to send End_Device_Bind_req messages to the Coordinator
within a time window (60 s). The payload of each message is a simple descriptor which lists input and
output clusterIDs. The Coordinator matches the requests by pairing complementary clusterIDs. After a
match has been made, it sends messages to bind the devices together. When the process is over, both
devices will have entries in their binding tables which support indirect addressing of messages between
their bound endpoints.
R1->C End_Device_Bind_req
R2->C End_Device_Bind_req
R1, R2 send End_Device_Bind_req within 60 s of each other to C
C matches the requests.
C tests one to see if binding is already in place:
R2<-C Unbind_req
R2->C Unbind-rsp (status code - NO_ENTRY)
C proceeds to create binding table entries on the two devices.
R1<-C Bind_req
R1->C Bind_rsp
R2<-C Bind_req
R2->C Bind_rsp
C sends responses to the original End_Device_Bind_req messages.
R1-C End_Device_Bind_req
R2->C End_Device_Bind_req
R1, R2 send End_Device_Bind_req within 60 s of each other to C
C matches the requests.
C tests one to see if binding is already in place:
R2<-C Unbind_req
R2->C Unbind-rsp (status code - SUCCESS)
C proceeds to remove binding table entries from the two devices.
R1<-C Unbind_req
R1->C Unbind_rsp
R2<-C Unbind_req
R2->C Unbind_rsp
C sends responses to the original End_Device_Bind_req messages.
R1-Server direction(0x00). The second field is a transaction sequence number which is used to
associate the response with the command request. The third field is the command identifier for "Add
Group" ( 0x00)[2].
ZCL_payload = "3412 04 41 42 43 44"
The first two bytes is the group Id to add in little endian representation. The next byte is the string name
length (00 if no string is wanted). The other bytes are the descriptive ASCII string name ("ABCD") for the
group table entry. Note the string is represented with its length in the first byte, and the other bytes
containing the ASCII characters.
The example packet in raw hex byte form:
7e001e11010013a2004047b55cfffee6e70006c105000001ee0034120441424344c7
The response in raw hex byte form, consisting of two packets:
7e0018910013a2004047b55cfffee7e68006c1050009ee0000341238
7e00078b01fffe00000076
The response in decoded form:
ZigBee Explicit Rx Indicator
API 0x91 64DestAddr 0x0013A2004047B55C 16DestAddr 0xFFFE
ClusterID 0x8006 ProfileID 0xC105
SrcEP 0xE7
DestEP 0xE6
Options 0x00
RF_Data 0x09EE00003412
The response in terms of Preamble, ZCL Header, and ZCL payload:
Preamble = "910013a2004047b55cfffee7e68006c10500"
The packet has its endpoint values reversed from the request, and the clusterID is 0x8006 indicating a
Group cluster response.
ZCL_header = "09 ee 00"
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The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Server->
Client direction. The second field is a transaction sequence number which is used to associate the response
with the command request. The third field is the command identifier "Add Group" (0x00)[2].
ZCL_payload = "00 3412"
The first byte is a status byte (SUCCESS=0x00)[3][4]. The next two bytes hold the group ID (0x1234) in
little endian form.
And here is the decoded second message, which is a Tx Status for the original command request. If the
FrameId value in the original command request had been zero, or if no space was available in the transmit
UART buffer, then no Tx Status message would occur.
ZigBee Tx Status
API 0x8B
FrameID 0x01
16DestAddr 0xFFFE
Transmit Retries 0x00 Delivery Status 0x00 Discovery Status 0x00 Success
View Group
The purpose of the View Group command is to get the name string which is associated with a particular
endpoint and groupID.
The intent of the example is to get the name string associated with the endpoint E7 and groupID 1234.
The packet:
Preamble = "11 01 "+LocalDevice64Addr+"FFFE E6 E7 0006 C105 00 00"
The packet is addressed to the local node, using a source endpoint of 0xE6, clusterID of 0x0006, and
profileID of 0xC105. The destination endpoint E7 is the endpoint parameter for the "View Group" command.
ZCL_header = "01 ee 01"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Client>Server direction(0x00). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "View Group" (0x01) [5].
ZCL_payload = "3412"
The two byte value is the groupID in little-endian representation.
The packet in raw hex byte form:
7e001911010013a2004047b55cfffee6e70006c105000001ee013412d4
The response in raw hex byte form, consisting of two packets:
7e001d910013a2004047b55cfffee7e68006c1050009ee01003412044142434424
7e00078b01fffe00000076
The command response in decoded form:
ZigBee Explicit Rx Indicator
API 0x91 64DestAddr 0x0013A2004047B55C 16DestAddr 0xFFFE
ClusterID 0x8006 ProfileID 0xC105
SrcEP 0xE7
DestEP 0xE6
Options 0x00
RF_Data 0x09EE010034120441424344
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The response in terms of Preamble, ZCL Header, and ZCL payload:
Preamble = "910013a2004047b55cfffee7e68006c10500"
The packet has its endpoint values reversed from the request, and the clusterID is 0x8006 indicating a
Group cluster response.
ZCL_header = "09 ee 01"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Server>Client direction (0x08). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "View Group" (0x01) [6].
ZCL_payload = "00 3412 0441424344"
The first byte is a status byte (SUCCESS=0x00)[6][4]. The next two bytes hold the groupID (0x1234) in
little-endian form. The next byte is the name string length (0x04). The remaining bytes are the ASCII name
string characters ("ABCD").
And here is the decoded second message, which is a Tx Status for the original command request. If the
FrameId value in the original command request had been zero, or if no space was available in the transmit
UART buffer, then no Tx Status message would occur.
ZigBee Tx Status
API 0x8B
FrameID 0x01
16DestAddr 0xFFFE
Transmit Retries 0x00 Delivery Status 0x00 Discovery Status 0x00 Success
Get Group Membership (1 of 2)
The purpose of this first form of the Get Group Membership command is to get all the groupIDs associated
with a particular endpoint.
The intent of the example is to get all the groupIDs associated with endpoint E7.
The example packet is given in three parts, the preamble, ZCL Header, and ZCL payload:
Preamble = "11 01 "+LocalDevice64Addr+"FFFE E6 E7 0006 C105 00 00"
The packet is addressed to the local node, using a source endpoint of 0xE6, clusterID of 0x0006, and
profileID of 0xC105. The destination endpoint E7 holds the endpoint parameter for the "Get Group
Membership" command.
ZCL_header = "01 ee 02"
The first field (byte) is a frame control field which specifies a Cluster Specific command (0x02) using a
Client->Server direction(0x00). The second field is a transaction sequence number which is used to
associate the response with the command request. The third field is the command identifier for "Get Group
Membership" (0x02) [7].
ZCL_payload = "00"
The first byte is the group count. If it is zero, then all groupIDs with an endpoint value which matches the
given endpoint parameter will be returned in the response.
The example packet in raw hex byte form:
7e001811010013a2004047b55cfffee6e70006c105000001ee020019
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The response in raw hex byte form, consisting of two packets:
7e0019910013a2004047b55cfffee7e68006c1050009ee02ff01341235
7e00078b01fffe00000076
The response in decoded form:
ZigBee Explicit Rx Indicator
API 0x91 64DestAddr 0x0013A2004047B55C 16DestAddr 0xFFFE
ClusterID 0x8006 ProfileID 0xC105
SrcEP 0xE7
DestEP 0xE6
Options 0x00
RF_Data 0x09EE02FF013412
The response in terms of Preamble, ZCL Header, and ZCL Payload:
Preamble = "910013a2004047b55cfffee7e68006c10500"
The packet has the endpoints reversed from the request, and the clusterID is 0x8006 indicating a Group
cluster response.
ZCL_header = "09 ee 02"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Server>Client direction (0x08). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "Get Group Membership"
(0x02) [8].
ZCL_payload = "FF 01 3412"
The first byte is the remaining capacity of the group table. 0xFF means unknown. The XBee returns this
value because the capacity of the group table is dependent on the remaining capacity of the binding table,
thus the capacity of the group table is unknown. The second byte is the group count (0x01). The remaining
bytes are the groupIDs in little-endian representation.
And here is the decoded second message, which is a Tx Status for the original command request. If the
FrameId value in the original command request had been zero, or if no space was available in the transmit
UART buffer, then no Tx Status message would occur.
ZigBee Tx Status
API 0x8B
FrameID 0x01
16DestAddr 0xFFFE
Transmit Retries 0x00 Delivery Status 0x00 Discovery Status 0x00 Success
Get Group Membership (2 of 2)
The purpose of this second form of the Get Group Membership command is to get the set of groupIDs
associated with a particular endpoint which are a subset of a list of given groupIDs.
The intent of the example is to get the groupIDs associated with endpoint E7 which are a subset of a given
list of groupIDs (0x1234, 0x5678).
The example packet is given in three parts, the preamble, ZCL Header, and ZCL payload:
Preamble = "11 01 "+LocalDevice64Addr+"FFFE E6 E7 0006 C105 00 00"
The packet is addressed to the local node, using a source endpoint of 0xE6, clusterID of 0x0006, and
profileID of 0xC105. The destination endpoint E7 is the endpoint parameter for the "Get Group
Membership" command.
ZCL_header = "01 ee 02"
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The first field (byte) is a frame control field which specifies a Cluster Specific command (0x02) using a
Client->Server direction(0x00). The second field is a transaction sequence number which is used to
associate the response with the command request. The third field is the command identifier for "Get
Group Membership" (0x02) [7].
ZCL_payload = "02 34127856"
The first byte is the group count. The remaining bytes are a groupIDs which use little-endian
representation.
The example packet in raw hex byte form:
7e001c11010013a2004047b55cfffee6e70006c105000001ee02023412785603
The response in raw hex byte form, consisting of two packets:
7e0019910013a2004047b55cfffee7e68006c1050009ee02ff01341235
7e00078b01fffe00000076
The response in decoded form:
ZigBee Explicit Rx Indicator
API 0x91 64DestAddr 0x0013A2004047B55C 16DestAddr 0xFFFE
ClusterID 0x8006 ProfileID 0xC105
SrcEP 0xE7
DestEP 0xE6
Options 0x00
RF_Data 0x09EE02FF013412
The response in terms of Preamble, ZCL Header, and ZCL Payload:
Preamble = "910013a2004047b55cfffee7e68006c10500"
The packet has the endpoints reversed from the request, the clusterID is 0x8006 indicating a Group cluster
response.
ZCL_header = "09 ee 02"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Server>Client direction (0x08). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "Get Group Membership"
(0x02) [8].
ZCL_payload = "FF 01 3412"
The first byte is the remaining capacity of the group table. 0xFF means unknown. The XBee returns this
value because the capacity of the group table is dependent on the remaining capacity of the binding table,
thus the capacity of the group table is unknown. The second byte is the group count (0x01). The remaining
bytes are the groupIDs in little-endian representation.
And here is the decoded second message, which is a Tx Status for the original command request. If the
FrameId value in the original command request had been zero, or if no space was available in the transmit
UART buffer, then no Tx Status message would occur.
ZigBee Tx Status
API 0x8B
FrameID 0x01
16DestAddr 0xFFFE
Transmit Retries 0x00 Delivery Status 0x00 Discovery Status 0x00 Success
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Remove Group
The purpose of the Remote Group command is to remove a Group Table entry which associates a given
endpoint with a given groupID.
The intent of the example is to remove the association of groupID [TBD] with endpoint E7.
The example packet is given in three parts, the preamble, ZCL Header, and ZCL payload:
Preamble = "11 01 "+LocalDevice64Addr+"FFFE E6 E7 0006 C105 00 00"
The packet is addressed to the local node, using a source endpoint of 0xE6, clusterID of 0x0006, and
profileID of 0xC105. The destination endpoint E7 is the endpoint parameter for the "Remove Group"
command.
ZCL_header = "01 ee 03"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Client>Server direction(0x00). The second field is a transaction sequence number which is used to associate
the response with the command request. The third field is the command identifier "Remove Group" (0x03)
[9].
ZCL_payload = "3412"
The two bytes value is the groupID to be removed in little-endian representation.
The packet in raw hex byte form:
7e001911010013a2004047b55cfffee6e70006c105000001ee033412d2
The response in raw hex byte form, consisting of two packets:
7e0018910013a2004047b55cfffee7e68006c1050009ee0300341235
7e00078b01fffe00000076
The command response in decoded form:
ZigBee Explicit Rx Indicator
API 0x91 64DestAddr 0x0013A2004047B55C 16DestAddr 0xFFFE
ClusterID 0x8006 ProfileID 0xC105
SrcEP 0xE7
DestEP 0xE6
Options 0x00
RF_Data 0x09EE03003412
The response in terms of Preamble, ZCL Header, and ZCL payload:
Preamble = "910013a2004047b55cfffee7e68006c10500"
The packet has its endpoint values reversed from the request, and the clusterID is 0x8006 indicating a
Group cluster response.
ZCL_header = "09 ee 03"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Server>Client direction (0x08). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "Remove Group" (0x03)
[10].
ZCL_payload = "00 3412"
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The first byte is a status byte (SUCCESS=0x00)[10][4]. The next two bytes is the groupID (0x1234) value
in little-endian form.
And here is the decoded second message, which is a Tx Status for the original command request. If the
FrameId value in the original command request had been zero, or if no space was available in the transmit
UART buffer, then no Tx Status message would occur.
ZigBee Tx Status
API 0x8B
FrameID 0x01
16DestAddr 0xFFFE
Transmit Retries 0x00 Delivery Status 0x00 Discovery Status 0x00 Success
Remove All Groups
The purpose of the Remove All Groups command is to clear all entries from the group table which are
associated with a target endpoint.
The intent of the example is to remove all groups associated with endpoint E7.
The packet:
Preamble = "11 01 "+LocalDevice64Addr+"FFFE E6 E7 0006 C105 00 00"
The packet is addressed to the local node, using a source endpoint of 0xE6, clusterId of 0x0006, and
profileID of 0xC105. The destination endpoint E7 is the endpoint parameter for the "Remove All Groups"
command.
ZCL_header = "01 ee 04"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Client>Server direction(0x00). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "Remove All Groups" (0x04)
[11].
ZCL_payload = ""
No payload is needed for this command.
The packet in raw hex byte form:
7e001711010013a2004047b55cfffee6e70006c105000001ee0417
The response in raw hex byte form, consisting of two packets:
7e0016910013a2004047b55cfffee7e68006c1050009ee04007c
7e00078b01fffe00000076
The command response in decoded form:
ZigBee Explicit Rx Indicator
API 0x91 64DestAddr 0x0013A2004047B55C 16DestAddr 0xFFFE
ClusterID 0x8006 ProfileID 0xC105
SrcEP 0xE7
DestEP 0xE6
Options 0x00
RF_Data 0x09ee0400
The response in terms of Preamble, ZCL Header, and ZCL payload.
Preamble = "910013a2004047b55cfffee7e68006c10500"
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The packet has its endpoints values reversed from the request, and the clusterID is 0x8006 indicating a
Group cluster response.
ZCL_header = "09 ee 04"
The first field is a frame control field which specifies a Cluster Specific command (0x01) using a Server>Client direction (0x08). The second field is a transaction sequence number which is used to associate the
response with the command request. The third field is the command identifier "Remove All Groups" (0x04)
[10].
ZCL_payload = "00"
The first byte is a status byte (SUCCESS=0x00)[4].
And here is the decoded second message, which is a Tx Status for the original command request. If the
FrameID value in the original command request had been zero, or if no space was available in the transmit
UART buffer, then no Tx Status message would occur.
ZigBee Tx Status
API 0x8B
FrameID 0x01
16DestAddr 0xFFFE
Transmit Retries 0x00 Delivery Status 0x00 Discovery Status 0x00 Success
Default Responses
Many errors are returned as a default response. For example, a RFData payload of a response containing
08010b788b would be decoded as:
ZCL_header = "08 01 03" - general command/server-to-client, transseqnum=1,
default_response_command(0x03)
ZCL_payload = "78 8b" - original cmdID, status code (0x8b) EMBER_ZCL_STATUS_NOT_FOUND
Common Status Codes
This section lists some of the more frequently occuring status codes.
0x00 EMBER_ZCL_STATUS_SUCCESS: Command request was successful
0x01 EMBER_ZCL_STATUS_FAILURE: Command request failed - for example, a call to remove an entry
from the group table returned an error
0x80 EMBER_ZCL_STATUS_MALFORMED_COMMAND: no RFData in the API frame; ZCL Payload appears
truncated from what is expected
0x81 EMBER_ZCL_STATUS_UNSUP_CLUSTER_COMMAND: unexpected direction in the Frame Control Field
of the ZCL Header; unexpected command identifier code value in the ZCL header
0x82 EMBER_ZCL_STATUS_UNSUP_GENERAL_COMMAND: unexpected frametype in the Frame Control
Field of the ZCL Header
0x84 EMBER_ZCL_STATUS_UNSUP_MANUF_GENERAL_COMMAND: unexpected manufacturer specific
indication in the Frame Control Field of the ZCL Header
0x8b EMBER_ZCL_STATUS_NOT_FOUND: An attempt at Get Group Membership or Remove Group could not
find a matching entry in the group table
A full set of status codes appears in the documentation [4].
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Bibliography
[1] ZigBee Cluster Library, document 075123r02, section 3.6.
The following cross references all appear in the ZCL document:
[2] Add Group Command, section 3.6.2.2.3.
[3] Add Group Response, section 3.6.2.3.1.
[4] Status Enumerations, section 2.5.3.
[5] View Group Command, section 3.6.2.2.4.
[6] View Group Response, section 3.6.2.3.2.
[7] Get Group Membership Command, section 3.6.2.2.5.
[8] Get Group Membership Response, section 3.6.2.3.3.
[9] Remove Group Command, section 3.6.2.2.6.
[10] Remove Group Response, section 3.6.2.3.4.
[11] Remove All Groups Command, section 3.6.2.2.7.
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7. Managing End Devices
ZigBee end devices are intended to be battery-powered devices capable of sleeping for extended periods of time. Since
end devices may not be awake to receive RF data at a given time, routers and coordinators are equipped with additional
capabilities (including packet buffering and extended transmission timeouts) to ensure reliable data delivery to end
devices.
End Device Operation
When an end device joins a ZigBee network, it must find a router or coordinator device that is allowing end devices
to join. Once the end device joins a network, a parent-child relationship is formed between the end device and the
router or coordinator that allowed it to join. See chapter 3 for details.
When the end device is awake, it sends poll request messages to its parent. When the parent receives a poll request,
it checks a packet queue to see if it has any buffered messages for the end device. It then sends a MAC layer
acknowledgment back to the end device that indicates if it has data to send to the end device or not.
If the end device receives the acknowledgment and finds that the parent has no data for it, the end device can
return to idle mode or sleep. Otherwise, it will remain awake to receive the data. This polling mechanism allows the
end device to enter idle mode and turn its receiver off when RF data is not expected in order to reduce current
consumption and conserve battery life.
The end device can only send data directly to its parent. If an end device must send a broadcast or a unicast
transmission to other devices in the network, it sends the message directly to its parent and the parent performs
any necessary route or address discoveries to route the packet to the final destination.
Parent Operation
Each router or coordinator maintains a child table that contains the addresses of its end device children. A router or
coordinator that has unused entries in its child table is said to have end device capacity, or the ability to allow new
end devices to join. If the child table is completely filled (such that the number of its end device children matches
the number of child table entries), the device cannot allow any more end devices to join to it.
Since the end device children are not guaranteed to be awake at a given time, the parent is responsible for
managing incoming data packets in behalf of its end device children. If a parent receives an RF data transmission
destined for one of its end device children, and if the parent has enough unused buffer space, it will buffer the
packet. The data packet will remain buffered until a timeout expires, or until the end device sends a poll request to
retrieve the data.
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The parent can buffer one broadcast transmission for all of its end device children. When a broadcast transmission is
received and buffered, the parent sets a flag in its child table when each child polls and retrieves the packet. Once all
children have received the broadcast packet, the buffered broadcast packet is discarded. If all children have not
received a buffered broadcast packet and a new broadcast is received, the old broadcast packet is discarded, the
child table flags are cleared, and the new broadcast packet is buffered for the end device children. This is
demonstrated in the figure below.
When an end device sends data to its parent that is destined for a remote device in the network, the parent buffers
the data packet until it can establish a route to the destination. The parent may perform a route or 16-bit address
discovery in behalf of its end device children. Once a route is established, the parent sends the data transmission to
the remote device.
End Device Poll Timeouts
To better support mobile end devices (end devices that can move around in a network), parent router and
coordinator devices have a poll timeout for each end device child. If an end device does not send a poll request
to its parent within the poll timeout, the parent will remove the end device from its child table. This allows the
child table on a router or coordinator to better accommodate mobile end devices in the network.
Packet Buffer Usage
Packet buffer usage on a router or coordinator varies depending on the application. The following activities can
require use of packet buffers for up to several seconds:
• Route and address discoveries
• Application broadcast transmissions
• Stack broadcasts (e.g. ZDO "Device Announce" messages when devices join a network)
• Unicast transmissions (buffered until acknowledgment is received from destination or retries exhausted)
• Unicast messages waiting for end device to wake.
Applications that use regular broadcasting or that require regular address or route discoveries will use up a
significant number of buffers, reducing the buffer availability for managing packets for end device children.
Applications should reduce the number of required application broadcasts, and consider implementing an
external address table or many-to-one and source routing if necessary to improve routing efficiency.
Non-Parent Device Operation
Devices in the ZigBee network treat data transmissions to end devices differently than transmissions to other
routers and coordinators. Recall that when a unicast transmission is sent, if a network acknowledgment is not
received within a timeout, the device resends the transmission. When transmitting data to remote coordinator or
router devices, the transmission timeout is relatively short since these devices are powered and responsive.
However, since end devices may sleep for some time, unicast transmissions to end devices use an extended timeout
mechanism in order to allow enough time for the end device to wake and receive the data transmission from its
parent.
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If a non-parent device does not know the destination is an end device, it will use the standard unicast timeout for
the transmission. However, provisions exist in the Ember ZigBee stack for the parent to inform the message sender
that the destination is an end device. Once the sender discovers the destination device is an end device, future
transmissions will use the extended timeout. See the XBee Router / Coordinator Configuration section in this chapter
for details.
XBee End Device Configuration
XBee end devices support three different sleep modes:
• Pin Sleep
• Cyclic Sleep
• Cyclic Sleep with pin wake-up
Pin sleep allows an external microcontroller to determine when the XBee should sleep and when it should wake by
controlling the Sleep_RQ pin. In contrast, cyclic sleep allows the sleep period and wake times to be configured
through the use of AT commands. Cyclic sleep with pin wake-up is the same as cyclic sleep except that the module
can be awakened before the sleep period expires by lowering the Sleep_Rq line. The sleep mode is configurable with
the SM command.
In both pin and cyclic sleep modes, XBee end devices poll their parent every 100ms while they are awake to retrieve
buffered data. When a poll request has been sent, the end device enables the receiver until an acknowledgment is
received from the parent. (It generally takes less than 10ms from the time the poll request is sent until the
acknowledgment is received.) The acknowledgment indicates if the parent has buffered data for the end device child
or not. If the acknowledgment indicates the parent has pending data, the end device will leave the receiver on to
receive the data. Otherwise, the end device will turn off the receiver and enter idle mode (until the next poll request
is sent) to reduce current consumption (and improve battery life).
Once the module enters sleep mode, the On/Sleep pin (pin 26) is de-asserted (low) to indicate the module is
entering sleep mode. If CTS hardware flow control is enabled (D7 command), the CTS pin (pin 12) is de-asserted
(high) when entering sleep to indicate that serial data should not be sent to the module. If the Associate LED pin is
configured (D5 command), the associate pin will be driven low to avoid using power to light the LED. Finally, the
Sleep_Rq pin will be configured as a pulled-down input so that an external device must drive it high to wake the
module. All other pins will be left unmodified during sleep so that they can operate as previously configured by the
user. The module will not respond to serial or RF data when it is sleeping. Applications that must communicate
serially to sleeping end devices are encouraged to observe CTS flow control.
When the XBee wakes from sleep, the On/Sleep pin is asserted (high), and if flow control is enabled, the CTS pin is
also asserted (low). The associate LED and all other pins resume their former configured operation. If the module
has not joined a network, it will scan all SC channels after waking to try and find a valid network to join.
Pin Sleep
Pin sleep allows the module to sleep and wake according to the state of the Sleep_RQ pin (pin 9). Pin sleep
mode is enabled by setting the SM command to 1.
When Sleep_RQ is asserted (high), the module will finish any transmit or receive operations and enter a low
power state. For example, if the module has not joined a network and Sleep_RQ is asserted (high), the module
will sleep once the current join attempt completes (i.e. when scanning for a valid network completes). The
module will wake from pin sleep when the Sleep_RQ pin is de-asserted (low).
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In the figure above, t1, t2, t3 and t4 represent the following events:
• t1 - Time when Sleep_RQ is asserted (high)
• t2 - Time when the XBee enters sleep (CTS state change only if hardware flow control is enabled)
• t3 - Time when Sleep_RQ is de-asserted (low) and the module wakes.
• t4 - Time when the module sends a poll request to its parent.
The time between t1 and t2 varies depending on the state of the module. In the worst case scenario, if the end
device is trying to join a network, or if it is waiting for an acknowledgment from a data transmission, the delay
could be up to a few seconds. the time between t3 and t4 is 1-2 ms for a regular module and about 6 ms for a
PRO module.
When the XBee is awake and is joined to a network, it sends a poll request to its parent to see if the parent has
any buffered data for it. The end device will continue to send poll requests every 100ms while it is awake.
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Demonstration of Pin Sleep
Parent and remote devices must be configured to buffer data correctly and to utilize adequate transmission
timeouts. See the XBee Router / Coordinator Configuration section in this chapter for details.
Cyclic Sleep
Cyclic sleep allows the module to sleep for a specified time and wake for a short time to poll its parent for any
buffered data messages before returning to sleep again. Cyclic sleep mode is enabled by setting the SM
command to 4 or 5. SM5 is a slight variation of SM4 that allows the module to be woken prematurely by
asserting the Sleep_RQ pin (pin 10). In SM5, the XBee can wake after the sleep period expires, or if a high-tolow transition occurs on the Sleep_RQ pin. Setting SM to 4 disables the pin wake option.
In cyclic sleep, the module sleeps for a specified time, and then wakes and sends a poll request to its parent to
discover if the parent has any pending data for the end device. If the parent has buffered data for the end
device, or if serial data is received, the XBee will remain awake for a time. Otherwise, it will enter sleep mode
immediately.
The On/Sleep line is asserted (high) when the module wakes, and is de-asserted (low) when the module sleeps.
If hardware flow control is enabled (D7 command), the CTS pin will assert (low) when the module wakes and
can receive serial data, and de-assert (high) when the module sleeps.
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In the figure above, t1, t2, and t3 represent the following events:
•T1 - Time when the module wakes from cyclic sleep
•T2 - Time when the module returns to sleep
•T3 - Later time when the module wakes from cyclic sleep.
The wake time and sleep time are configurable with software commands as described in the sections below.
Wake Time (Until Sleep)
In cyclic sleep mode (SM=4 or 5), if serial or RF data is received, the module will start a sleep timer (time
until sleep). Any data received serially or over the RF link will restart the timer. The sleep timer value is
settable with the ST command. While the module is awake, it will send poll request transmissions every
100ms to check its parent for buffered data messages. The module returns to sleep when the sleep timer
expires, or if the SI command is sent to it. The following image shows this behavior.
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DIN
ST = Time Awake
On/Sleep
A cyclic sleep end device enters sleep mode when no serial or RF data is received for ST time .
Legend
On/Sleep
Transmitting Poll
Request
Sleep Period
The sleep period is configured based on the SP, SN, and SO commands. The following table lists the
behavior of these commands.
Command
Range
Description
SP
0x20 - 0xAF0 (x 10 ms)
(320 - 28,000 ms)
Configures the sleep period of the module.
SN
1 - 0xFFFF
Configures the number of sleep periods
multiplier.
SO
0 - 0xFF
Defines options for sleep mode behavior.
0x02 - Always wake for full ST time
0x04 - Enable extended sleep (sleep for full
(SP * SN) time)
The XBee module supports both a short cyclic sleep and an extended cyclic sleep that make use of these
commands. These two modes allow the sleep period to be configured according to the application
requirements.
Short Cyclic Sleep
In short cyclic sleep mode, the sleep behavior of the module is defined by the SP and SN commands, and
the SO command must be set to 0x00 (default) or 0x02. In short cyclic sleep mode, the SP command
defines the sleep period and is settable up to 28 seconds. When the XBee enters short cyclic sleep, it
remains in a low power state until the SP time has expired.
After the sleep period expires, the XBee sends a poll request transmission to its parent to determine if its
parent has any buffered data waiting for the end device. Since router and coordinator devices can buffer
data for end device children up to 30 seconds, the SP range (up to 28 seconds) allows the end device to poll
regularly enough to receive buffered data. If the parent has data for the end device, the end device will
start its sleep timer (ST) and continue polling every 100ms to receive data. If the end device wakes and
finds that its parent has no data for it, the end device can return to sleep immediately.
The SN command can be used to control when the On/Sleep line is asserted (high). If SN is set to 1
(default), the On/Sleep line will be set high each time the XBee wakes from sleep. Otherwise, if SN is
greater than 1, the On/Sleep line will only be set high if RF data is received, or after SN wake cycles occur.
This allows an external device to remain powered off until RF data is received, or until a number of sleep
periods have expired (SN sleep periods). This mechanism allows the XBee to wake at regular intervals to
poll its parent for data without waking an external device for an extended time (SP * SN time). This is
shown in the figure below.
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On/Sleep
(SN = 3)
On/Sleep
(SN = 1)
∆t = SP * SN
Transmitting poll request to parent
∆t = SP
∆t = SP * SN
Transmitting poll request to parent
∆t = SP
Setting SN > 1 allows the XBee to silently poll for data without asserting On /Sleep. If RF data is received
when polling, On/Sleep will immediately assert .
Legend
Sleep_RQ
Transmitting Poll
Request
Note: SP controls the packet buffer time on routers and coordinators. SP should be set on all router and coordinator
devices to match the longest end device SP time. See the XBee Router / Coordinator Configuration section for details.
Extended Cyclic Sleep
In extended cyclic sleep operation, an end device can sleep for a multiple of SP time which can extend the
sleep time up to several days. The sleep period is configured using the SP and SN commands. The total
sleep period is equal to (SP * SN) where SP is measured in 10ms units. The SO command must be set
correctly to enable extended sleep.
Since routers and coordinators can only buffer incoming RF data for their end device children for up to 30
seconds, if an end device sleeps longer than 30 seconds, devices in the network need some indication when
an end device is awake before they can send data to it. End devices that use extended cyclic sleep should
send a transmission (such as an IO sample) when they wake to inform other devices that they are awake
and can receive data. It is recommended that extended sleep end devices set SO to wake for the full ST
time in order to provide other devices with enough time to send messages to the end device.
Similar to short cyclic sleep, end devices running in this mode will return to sleep when the sleep timer
expires, or when the SI command is received.
Transmitting RF Data
An end device may transmit data when it wakes from sleep and has joined a network. End devices transmit
directly to their parent and then wait for an acknowledgment to be received. The parent will perform any
required address and route discoveries to help ensure the packet reaches the intended destination before
reporting the transmission status to the end device.
Receiving RF Data
After waking from sleep, an end device sends a poll request to its parent to determine if the parent has any
buffered data for it. In pin sleep mode, the end device polls every 100ms while the Sleep_RQ pin is de-asserted
(low). In cyclic sleep mode, the end device will only poll once before returning to sleep unless the sleep timer
(ST) is started (serial or RF data is received). If the sleep timer is started, the end device will continue to poll
every 100ms until the sleep timer expires.
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This firmware includes an adaptive polling enhancement where, if an end device receives RF data from its
parent, it sends another poll after a very short delay to check for more data. The end device continues to poll at
a faster rate as long as it receives data from its parent. This feature greatly improves data throughput to end
devices. When the end device no longer receives data from its parent, it resumes polling every 100ms.
I/O Sampling
End devices can be configured to send one or more I/O samples when they wake from sleep. To enable I/O
sampling on an end device, the IR command must be set to a non-zero value, and at least one analog or digital
I/O pin must be enabled for sampling (D0 - D9, P0-P4 commands). If I/O sampling is enabled, an end device
sends an I/O sample when it wakes and starts the ST timer. It will continue sampling at the IR rate until the
sleep timer (ST) has expired. See chapter 8 for details.
Waking End Devices with the Commissioning Pushbutton
If the commissioning pushbutton functionality is enabled (D0 command), a high-to-low transition on the AD0/
DIO0 pin (pin 33) will cause an end device to wake for 30 seconds. See the Commissioning Pushbutton section
in chapter 7 for details.
Parent Verification
Since an end device relies on its parent to maintain connectivity with other devices in the network, XBee end
devices include provisions to verify its connection with its parent. End devices monitor their link with their
parent when sending poll messages and after a power cycle or reset event as described below.
When an end device wakes from sleep, it sends a poll request to its parent. In cyclic sleep, if RF or serial data is
not received and the sleep timer is not started, the end device polls one time and returns to sleep for another
sleep period. Otherwise, the end device continues polling every 100ms. If the parent does not send an
acknowledgment response to three consecutive poll request transmissions, the end device assumes the parent
is out of range, and attempts to find a new parent.
After a power-up or reset event, the end device does an orphan scan to locate its parent. If the parent does not
send a response to the orphan scan, the end device attempts to find a new parent.
Rejoining
Once all devices have joined a ZigBee network, the permit-joining attribute should be disabled such that new
devices are no longer allowed to join the network. Permit-joining can be enabled later as needed for short
times. This provides some protection in preventing other devices from joining a live network.
If an end device cannot communicate with its parent, the end device must be able to join a new parent to
maintain network connectivity. However, if permit-joining is disabled in the network, the end device will not find
a device that is allowing new joins.
To overcome this problem, ZigBee supports rejoining, where an end device can obtain a new parent in the same
network even if joining is not enabled. When an end device joins using rejoining, it performs a PAN ID scan to
discover nearby networks. If a network is discovered that has the same 64-bit PAN ID as the end device, it will
join the network by sending a rejoin request to one of the discovered devices. The device that receives the
rejoin request will send a rejoin response if it can allow the device to join the network (i.e. child table not full).
The rejoin mechanism can be used to allow a device to join the same network even if permit-joining is disabled.
To enable rejoining, NJ should be set less than 0xFF on the device that will join. If NJ < 0xFF, the device
assumes the network is not allowing joining and first tries to join a network using rejoining. If multiple rejoining
attempts fail, or if NJ=0xFF, the device will attempt to join using association.
XBee Router/Coordinator Configuration
XBee routers and coordinators may require some configuration to ensure the following are set correctly:
• RF packet buffering timeout
• Child poll timeout
• Transmission timeout.
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The value of these timeouts depends on the sleep time used by the end devices. Each of these timeouts are
discussed below.
RF Packet Buffering Timeout
When a router or coordinator receives an RF data packet intended for one of its end device children, it buffers
the packet until the end device wakes and polls for the data, or until a packet buffering timeout occurs. This
timeout is settable using the SP command. The actual timeout is (1.2 * SP), with a minimum timeout of 1.2
seconds and a maximum of 30 seconds. Since the packet buffering timeout is set slightly larger than the SP
setting, SP should be set the same on routers and coordinators as it is on cyclic sleep end devices. For pin sleep
devices, SP should be set as long as the pin sleep device can sleep, up to 30 seconds.
Note: In pin sleep and extended cyclic sleep, end devices can sleep longer than 30 seconds. If end devices sleep
longer than 30 seconds, parent and non-parent devices must know when the end device is awake in order to
reliably send data. For applications that require sleeping longer than 30 seconds, end devices should transmit
an IO sample or other data when they wake to alert other devices that they can send data to the end device.
Child Poll Timeout
Router and coordinator devices maintain a timestamp for each end device child indicating when the end device
sent its last poll request to check for buffered data packets. If an end device does not send a poll request to its
parent for a certain period of time, the parent will assume the end device has moved out of range and will
remove the end device from its child table. This allows routers and coordinators to be responsive to changing
network conditions. The NC command can be issued at any time to read the number of remaining (unused) child
table entries on a router or coordinator.
The child poll timeout is settable with the SP and SN commands. SP and SN should be set such that SP * SN
matches the longest expected sleep time of any end devices in the network. The actual timeout is calculated as
(3 * SP * SN), with a minimum of 5 seconds. For networks consisting of pin sleep end devices, the SP and SN
values on the coordinator and routers should be set such that SP * SN matches the longest expected sleep
period of any pin sleep device. The 3 multiplier ensures the end device will not be removed unless 3 sleep cycles
pass without receiving a poll request. The poll timeout is settable up to a couple of months.
Adaptive Polling
The PO command determines the regular polling rate. However, if RF data has been recently received by an
end device, it is likely that yet more RF data could be on the way. Therefore, the end device will poll at a
faster rate, gradually decreasing its adaptive poll rate until polling resumes at the regular rate as defined by
the PO command.
Transmission Timeout
As mentioned in chapter 4, when sending RF data to a remote router, since routers are always on, the timeout
is based on the number of hops the transmission may traverse. This timeout it settable using the NH command.
(See chapter 4 for details.)
Since end devices may sleep for lengthy periods of time, the transmission timeout to end devices also includes
some allowance for the sleep period of the end device. When sending data to a remote end device, the
transmission timeout is calculated using the SP and NH commands. If the timeout occurs and an
acknowledgment has not been received, the source device will resend the transmission until an
acknowledgment is received, up to two more times.
The transmission timeout per attempt is:
3 * ((unicast router timeout) + (end device sleep time)), or
3 * ((50 * NH) + (1.2 * SP)), where SP is measured in 10ms units.
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Putting It All Together
Short Sleep Periods
Pin and cyclic sleep devices that sleep less than 30 seconds can receive data transmissions at any time since
their parent device(s) will be able to buffer data long enough for the end devices to wake and poll to receive the
data. SP should be set the same on all devices in the network. If end devices in a network have more than one
SP setting, SP on the routers and coordinators should be set to match the largest SP setting of any end device.
This will ensure the RF packet buffering, poll timeout, and transmission timeouts are set correctly.
Extended Sleep Periods
Pin and cyclic sleep devices that might sleep longer than 30 seconds cannot receive data transmissions reliably
unless certain design approaches are taken. Specifically, the end devices should use IO sampling or another
mechanism to transmit data when they wake to inform the network they can receive data. SP and SN should be
set on routers and coordinators such that (SP * SN) matches the longest expected sleep time. This configures
the poll timeout so end devices are not expired from the child table unless a poll request is not received for 3
consecutive sleep periods.
As a general rule of thumb, SP and SN should be set the same on all devices in almost all cases.
Sleep Examples
This section covers some sample XBee configurations to support different sleep modes. Several AT commands are
listed with suggested parameter values. The notation in this section includes an '=' sign to indicate what each
command register should be set to - for example, SM=4. This is not the correct notation for setting command values
in the XBee. In AT command mode, each command is issued with a leading 'AT' and no '=' sign - for example ATSM4.
In the API, the two byte command is used in the command field, and parameters are populated as binary values in
the parameter field.
Example 1: Configure a device to sleep for 20 seconds, but set SN such that the On/Sleep line will
remain de-asserted for up to 1 minute.
The following settings should be configured on the end device.
SM = 4 (cyclic sleep) or 5 (cyclic sleep, pin wake)
SP = 0x7D0 (2000 decimal). This causes the end device to sleep for 20 seconds since SP is measured in
units of 10ms.
SN = 3. (With this setting, the On/Sleep pin will assert once every 3 sleep cycles, or when RF data is
received)
SO = 0
All router and coordinator devices on the network should set SP to match SP on the end device. This
ensures that RF packet buffering times and transmission timeouts will be set correctly.
Since the end device wakes after each sleep period (ATSP), the SN command can be set to 1 on all routers
and the coordinator.
Example 2: Configure an end device to sleep for 20 seconds, send 4 IO samples in 2 seconds, and return to sleep.
Since SP is measured in 10ms units, and ST and IR are measured in 1ms units, configure an end device
with the following settings:
SM = 4 (cyclic sleep) or 5 (cyclic sleep, pin wake)
SP = 0x7D0 (2000 decimal). This causes the end device to sleep for 20 seconds.
SN = 1
SO = 0
ST = 0x7D0 (2000 decimal). This sets the sleep timer to 2 seconds.
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IR = 0x258 (600 decimal). Set IR to a value greater than (2 seconds / 4) to get 4 samples in 2 seconds.
The end device sends an IO sample at the IR rate until the sleep timer has expired.
At least one analog or digital IO line must be enabled for IO sampling to work. To enable pin 32 (AD1/DIO1)
as a digital input line, the following must be set:
D1 = 3
All router and coordinator devices on the network should set SP to match SP on the end device. This
ensures that RF packet buffering times and transmission timeouts will be set correctly.
Example 3: Configure a device for extended sleep: to sleep for 4 minutes.
SP and SN must be set such that SP * SN = 4 minutes. Since SP is measured in 10ms units, the following
settings can be used to obtain 4 minute sleep.
SM = 4 (cyclic sleep) or 5 (cyclic sleep, pin wake)
SP = 0x7D0 (2000 decimal, or 20 seconds)
SN = 0x0B (12 decimal)
SO = 0x04 (enable extended sleep)
With these settings, the module will sleep for SP * SN time, or (20 seconds * 12) = 240 seconds = 4
minutes.
For best results, the end device should send a transmission when it wakes to inform the coordinator (or
network) when it wakes. It should also remain awake for a short time to allow devices to send data to it.
The following are recommended settings.
ST = 0x7D0 (2 second wake time)
SO = 0x06 (enable extended sleep and wake for ST time)
IR = 0x800 (send 1 IO sample after waking). At least one analog or digital IO sample should be enabled for
IO sampling.
With these settings, the end device will wake after 4 minutes and send 1 IO sample. It will then remain
awake for 2 seconds before returning to sleep.
SP and SN should be set to the same values on all routers and coordinators that could allow the end device
to join. This will ensure the parent does not timeout the end device from its child table too quickly.
The SI command can optionally be sent to the end device to cause it to sleep before the sleep timer
expires.
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8. XBee Analog and Digital I/O Lines
XBee ZB firmware supports a number of analog and digital I/O pins that are configured through software commands.
Analog and digital I/O lines can be set or queried. The following table lists the configurable I/O pins and the
corresponding configuration commands.
Module Pin Names
Module Pin
AT Command
Command Range
DOUT/DIO13
P3
0, 1, 3-5
DIN/CONFIG/DIO14
P4
0, 1, 3-5
PWM RSSI/DIO10
P0
0, 1, 3-5
PWM1/DIO11
P1
0, 1, 3-5
DTR/Slp_Rq/DIO8
10
D8
0, 1, 3-5
PTI_DATA/SPI_Attn/ADC5/
12
DIO19
P9
0, 1, 6
SPI_SClk/DIO18
14
P8
0, 1
SPI_SSel/DIO17
15
P7
0, 1
SPI_MOSI/DIO16
16
P6
0, 1
SPI_MISO/DIO15
17
P5
0,1
JTMS/SWDIO/DIO12/CD
21
P2
0, 3-5
JTRst/DIO4
24
D4
0, 3-5
CTS/DIO7
25
D7
0, 1, 3-7
JTDO/On_SLP/DIO9
26
D9
0, 1, 3-5
JTDI/Assoc/DIO5
28
D5
0, 1, 3-5
RTS/DIO6/SClk2
29
D6
0, 1, 3-5
AD3/DIO3
30
D3
0, 2-5
AD2/DIO2
31
D2
0, 2-5
PTI_En/AD1/DIO1
32
D1
0, 2-6
AD0/DIO0/Comm
33
D0
0-5
XBee ZB Through Hole RF Module
Module Pin Names Module Pin AT Command Command Range
Module Pin Names
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Module Pin
AT Command
Command Range
DIO13/DOUT
P3
0, 1, 3-5
DIO14/DIN/nCONFIG
P4
0, 1, 3-5
DIO12/PWM2/SWDIO/
SPI_MISO
P2
0, 1, 3-5
DIO10/PWM RSSI/DAC0
P0
0, 1, 3-5
DIO11/PWM1/DAC1
P1
0, 1, 3-5
DIO8/nDTR/SLP_RQ
D8
0, 1, 3-5
DIO4/SPI_MOSI
11
D4
0, 1, 3-5
DIO7/nCTS
12
D7
0, 1, 3-7
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Module Pin Names
Module Pin
AT Command
Command Range
DIO9/On/nSLEEP/SWO
13
D9
0, 1, 3-5
DIO5/ASSOC/JTDI
15
D5
0, 1, 3-5
DIO6/nRTS
16
D6
0, 1, 3-5
DIO3/AD3/SPI_nSSEL
17
D3
0-5
DIO2/AD2/SPI_SCLK
18
D2
0-5
DIO1/AD1/SPI_nATTN
19
D1
0-6
DIO0/AD0/CommBtn
20
D0
0-5
I/O Configuration
To enable an analog or digital I/O function on one or more XBee module pin(s), the appropriate configuration
command must be issued with the correct parameter. After issuing the configuration command, changes must
be applied on the module for the I/O settings to take effect.
Pin Command Parameter
Description
Disabled. (See below)
Peripheral control
Analog
Data in monitored. (See below)
Data out default low
Data out default high
RS485 enable low / packet trace interface
RS485 enable high
>7
Unsupported
When the pin command parameter is a 0 or a 3, it operates the same on this platform, except that the pin will not be
monitored by I/O sampling if the parameter is 0.
Inputs have three variations:
• floating
• pulled-up
• pulled-down
A floating input is appropriate if the pin is attached to an output that always drives the line. In this case, a pull-up
or pull-down resistor would cause more current to be drawn.
A pulled-up input is useful where there might not always be an external source to drive the pin and it is desirable to
have the line read high in the absence of an external driver.
Likewise, a pulled-down input is useful when there is not always an external source to drive the pin and it is desirable to have the line read low in the absence of an external driver.
Two commands are available to configure the input type:
• PR determines whether or not an input is pulled. If the corresponding bit in PR is set, then the signal will be
pulled. If it is clear, then the signal will be floating.
• PD determines the pull direction. It only applies when the corresponding bit in PR is set. The bit in PD should
be set to enable an internal pull-up resistor. It should be cleared to enable an internal pull-down resistor.
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I/O Sampling
The XBee ZB modules have the ability to monitor and sample the analog and digital I/O lines. I/O samples can be
read locally or transmitted to a remote device to provide indication of the current I/O line states. API mode must be
enabled on the receiving device in order to send I/O samples out the serial port. If this mode is not enabled, then
remote I/O samples will be discarded
There are three ways to obtain I/O samples, either locally or remotely:
• Queried Sampling
• Periodic Sampling
• Change Detection Sampling.
IO sample data is formatted as shown in the table below
Bytes
Name
Sample Sets
Description
Number of sample sets in the packet. (Always set to 1.)
Indicates which digital IO lines have sampling enabled. Each bit corresponds to one
digital IO line on the module.
• bit 0 = AD0/DIO0
• bit 1 = AD1/DIO1
• bit 2 = AD2/DIO2
• bit 3 = AD3/DIO3
• bit 4 = DIO4
• bit 5 = ASSOC/DIO5
• bit 6 = RTS/DIO6
Digital Channel Mask
• bit 7 = CTS/GPIO7
• bit 8 = Slp_Rq/DIO8
• bit 9 = On_Slp/DIO9
• bit 10 = RSSI/DIO10
• bit 11 = PWM/DIO11
• bit 12 = CD/DIO12
• bit 13 = DOUT/DIO13
• bit 14 = DIN/DIO14
For example, a digital channel mask of 0x002F means DIO0,1,2,3, and 5 are enabled
as digital I/O.
Indicates which lines have analog inputs enabled for sampling. Each bit in the analog
channel mask corresponds to one analog input channel.
• bit 0 = AD0/DIO0
Analog Channel Mask
Variable Sampled Data Set
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•
bit 1 = AD1/DIO1
•
bit 2 = AD2/DIO2
•
bit 3 = AD3/DIO3
•
bit 7 = Supply Voltage
A sample set consisting of 1 sample for each enabled ADC and/or DIO channel,
which has voltage inputs of 1143.75 and 342.1875mV.
If any digital I/O lines are enabled, the first two bytes of the data set indicate the state
of all enabled digital I/O. Only digital channels that are enabled in the Digital Channel
Mask bytes have any meaning in the sample set. If no digital I/O are enabled on the
device, these 2 bytes will be omitted.
Following the digital I/O data (if any), each enabled analog channel will return 2 bytes.
The data starts with AIN0 and continues sequentially for each enabled analog input
channel up to AIN3, and the supply voltage (if enabled) at the end.
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The sampled data set will include 2 bytes of digital I/O data only if one or more I/O lines on the device are
configured as digital I/O. If no pins are configured as digital IO, these 2 bytes will be omitted. Pins are configured as
digital I/O by setting them to a value of 3, 4, or 5.
The digital I/O data is only relevant if the same bit is enabled in the digital I/O mask.
Analog samples are returned as 10-bit values. The analog reading is scaled such that 0x0000 represents 0 V, and
0x3FF = 1.2 V. (The analog inputs on the module cannot read more than 1.2 V.) Analog samples are returned in
order starting with AIN0 and finishing with AIN3, and the supply voltage. Only enabled analog input channels return
data as shown in the figure below.
To convert the A/D reading to mV, do the following:
AD(mV) = (A/D reading * 1200mV) / 1024
The reading in the sample frame represents voltage inputs of 1143.75 and 342.1875 mV for AD0 and AD1
respectively.
Queried Sampling
The IS command can be sent to a device locally, or to a remote device using the API remote command frame
(see chapter 8 for details). When the IS command is sent, the receiving device samples all enabled digital IO
and analog input channels and returns an IO sample. If IS is sent locally, the IO sample is sent out the serial
port. If the IS command was received as a remote command, the IO sample is sent over-the-air to the device
that sent the IS command.
If the IS command is issued in command mode, the module returns a carriage return-delimited list containing
the above-listed fields. If the IS command is issued in API mode, an API command response contains the same
information.
The following table shows an example of the fields in an IS response.
Example
Sample AT Response
0x01
[1 sample set]
0x0C0C
[Digital Inputs: DIO 2, 3, 10, 11 low]
0x03
[Analog Inputs: A/D 0, 1]
0x0408
[Digital input states: DIO 3, 10 high, DIO 2, 11 low]
0x03D0
[Analog input ADIO 0= 0x3D0]
0x0124
[Analog input ADIO 1=0x120]
Periodic I/O Sampling
Periodic sampling allows an XBee module to take an I/O sample and transmit it to a remote device at a periodic
rate. The periodic sample rate is set by the IR command. If IR is set to 0, periodic sampling is disabled. For all
other values of IR, data will be sampled after IR milliseconds have elapsed and transmitted to a remote device.
The DH and DL commands determine the destination address of the I/O samples. DH and DL can be set to 0 to
transmit to the coordinator, or to the 64-bit address of the remote device (SH and SL). Only devices running in
API mode can send I/O data samples out their serial port. Devices running in transparent mode will discard
received I/O data samples.
A sleeping end device will transmit periodic IO samples at the IR rate until the ST timer expires and the device
can resume sleeping.
Change Detection Sampling
Modules can be configured to transmit a data sample immediately whenever a monitored digital I/O pin changes
state. The IC command is a bitmask that can be used to set which digital I/O lines should be monitored for a
state change. If one or more bits in IC is set, an I/O sample will be transmitted as soon as a state change is
observed in one of the monitored digital IO lines. Change detection samples are transmitted to the 64-bit
address specified by DH and DL.
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RSSI PWM
The XBee module features an RSSI/PWM pin (pin 7) that, if enabled, will adjust the PWM output to indicate the
signal strength of the last received packet. The P0 (P-zero) command is used to enable the RSSI pulse width
modulation (PWM) output on the pin. If P0 is set to 1 (and P1 is not set to 1), the RSSI/PWM pin will output a pulse
width modulated signal where the frequency is adjusted based on the received signal strength of the last packet.
Otherwise, for all other P0 settings, the pin can be used for general purpose IO.
When a data packet is received, if P0 is set to enable the RSSI/PWM feature, the RSSI PWM output is adjusted based
on the RSSI of the last packet. The RSSI/PWM output will be enabled for a time based on the RP command. Each
time an RF packet is received, the RSSI/PWM output is adjusted based on the RSSI of the new packet, and the RSSI
timer is reset. If the RSSI timer expires, the RSSI/PWM pin is driven low. RP is measured in 100ms units and
defaults to a value of 40 (4 seconds).
The RSSI PWM runs at 12MHz and has 2400 total counts (200us period).
RSSI (in dBm) is converted to PWM counts using the following equation:
PWM counts = (41 * RSSI_Unsigned) - 5928
I/O Examples
Example 1: Configure the following I/O settings on the XBee.
Configure AD1/DIO1 as a digital input with pullup resistor enabled
Configure AD2/DIO2 as an analog input
Configure DIO4 as a digital output, driving high.
To configure AD1/DIO1 as an input, issue the ATD1 command with a parameter of 3 ("ATD13"). To enable
pull-up resistors on the same pin, the PR command should be issued with bit 3 set (e.g. ATPR8, ATPR1FFF,
etc.).
The ATD2 command should be issued with a parameter of 2 to enable the analog input ("ATD22"). Finally,
DIO4 can be set as an output, driving high by issuing the ATD4 command with a parameter value of 5
("ATD45").
After issuing these commands, changes must be applied before the module IO pins will be updated to the
new states. The AC or CN commands can be issued to apply changes (e.g. ATAC).
Example 2: Calculate the PWM counts for a packet received with an RSSI of -84dBm.
RSSI = -84 = 0xAC = 172 decimal (unsigned)
PWM counts = (41 * 172) - 5928
PWM counts = 1124
With a total of 2400 counts, this yields an ON time of (1124 / 2400) = 46.8%
Example 3: Configure the RSSI/PWM pin to operate for 2 seconds after each received RF
packet.
First, ensure the RSSI/PWM functionality is enabled by reading the P0 (P-zero) command. It should be set
to 1 (default).
To configure the duration of the RSSI/PWM output, set the RP command. To achieve a 2 second PWM
output, set RP to 0x14 (20 decimal, or 2 seconds) and apply changes (AC command).
After applying changes, all received RF data packets should set the RSSI timer for 2 seconds.
PWM1
When P1 is configured for peripheral operation by setting the value to 1, it outputs a 50% duty cycle PWM with a
clock rate of 32,787 Hz, which is a period of 30.5 s. The main purpose of the PWM output is to provide a clock for
the PLUS processor, although it may also be used for other purposes.
*When this feature is enabled, the RSSI PWM output is automatically disabled, even if it is configured.
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9. XBee ZigBee API Operation
As an alternative to Transparent Operation, API (Application Programming Interface) Operations are available. API
operation requires that communication with the module be done through a structured interface (data is communicated in
frames in a defined order). The API specifies how commands, command responses and module status messages are sent
and received from the module using a serial port Data Frame.
Please note that Digi may add new API frames to future versions of firmware, so please build into your software interface
the ability to filter out additional API frames with unknown Frame Types.
API Frame Specifications
Two API modes are supported and both can be enabled using the AP (API Enable) command. Use the following AP
parameter values to configure the module to operate in a particular mode:
•AP = 1: API Operation
•AP = 2: API Operation (with escaped characters)
API Operation (AP parameter = 1)
When this API mode is enabled (AP = 1), the serial port data frame structure is defined as follows:
Serial Port Data Frame Structure:
Start Delimiter
(Byte 1)
0x7E
Length
(Bytes 2-3)
MSB
LSB
Frame Data
(Bytes 4-n)
Checksum
(Byte n + 1)
API-specific Structure
1 Byte
MSB = Most Significant Byte, LSB = Least Significant Byte
Any data received prior to the start delimiter is silently discarded. If the frame is not received correctly or if
the checksum fails, the module will reply with a module status frame indicating the nature of the failure.
API Operation - with Escape Characters (AP parameter = 2)
This mode is only available on the UART, not on the SPI serial port. When this API mode is enabled (AP =
2), the UART data frame structure is defined as follows:
UART Data Frame Structure ‐ with escape control characters:
Start Delimiter
(Byte 1)
0x7E
Length
(Bytes 2-3)
MSB
LSB
Frame Data
(Bytes 4-n)
Checksum
(Byte n + 1)
API-specific Structure
1 Byte
Characters Escaped If Needed
MSB = Most Significant Byte, LSB = Least Significant Byte
Escape characters. When sending or receiving a UART data frame, specific data values must be escaped
(flagged) so they do not interfere with the data frame sequencing. To escape an interfering data byte,
insert 0x7D and follow it with the byte to be escaped XOR’d with 0x20.
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XBee®/XBee‐PRO® ZB RF Modules
Data bytes that need to be escaped:
•0x7E – Frame Delimiter
•0x7D – Escape
•0x11 – XON
•0x13 – XOFF
Example - Raw UART Data Frame (before escaping interfering bytes): 
0x7E 0x00 0x02 0x23 0x11 0xCB
0x11 needs to be escaped which results in the following frame: 
0x7E 0x00 0x02 0x23 0x7D 0x31 0xCB
Note: In the above example, the length of the raw data (excluding the checksum) is 0x0002 and the
checksum of the non-escaped data (excluding frame delimiter and length) is calculated as:
0xFF - (0x23 + 0x11) = (0xFF - 0x34) = 0xCB.
Length
The length field has a two-byte value that specifies the number of bytes that will be contained in the frame
data field. It does not include the checksum field.
Frame Data
Frame data of the serial port data frame forms an API-specific structure as follows:
Serial Port Data Frame & API‐specific Structure:
Start Delimiter
(Byte 1)
0x7E
Length
(Bytes 2-3)
MSB
LSB
Frame Data
(Bytes 4-n)
Checksum
(Byte n + 1)
API-specific Structure
1 Byte
API Identifier
Identifier-specific Data
cmdID
cmdData
The cmdID frame (API-identifier) indicates which API messages will be contained in the cmdData frame
(Identifier-specific data). Note that multi-byte values are sent big endian.The XBee modules support the
following API frames:
API Frame Names and Values
API Frame Names
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API ID
AT Command
0x08
AT Command - Queue Parameter Value
0x09
ZigBee Transmit Request
0x10
Explicit Addressing ZigBee Command Frame
0x11
Remote Command Request
0x17
Create Source Route
0x21
AT Command Response
0x88
Modem Status
0x8A
ZigBee Transmit Status
0x8B
ZigBee Receive Packet (AO=0)
0x90
ZigBee Explicit Rx Indicator (AO=1)
0x91
ZigBee IO Data Sample Rx Indicator
0x92
XBee Sensor Read Indicator (AO=0)
0x94
Node Identification Indicator (AO=0)
0x95
Remote Command Response
0x97
Over-the-Air Firmware Update Status
0xA0
Extended Modem Status
0x98
Route Record Indicator
0xA1
Many-to-One Route Request Indicator
0xA3
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Checksum
To test data integrity, a checksum is calculated and verified on non-escaped data.
To calculate: Not including frame delimiters and length, add all bytes keeping only the lowest 8 bits of the
result and subtract the result from 0xFF.
To verify: Add all bytes (include checksum, but not the delimiter and length). If the checksum is correct,
the sum will equal 0xFF.
API Examples
Example: Create an API AT command frame to configure an XBee to allow joining (set NJ to 0xFF).
The frame should look like:
0x7E 0x00 0x05 0x08 0x01 0x4E 0x4A 0xFF 5F
Where 0x0005 = length
0x08 = AT Command API frame type
0x01 = Frame ID (set to non-zero value)
0x4E4A = AT Command ('NJ')
0xFF = value to set command to
0x5F = Checksum
The checksum is calculated as [0xFF - (0x08 + 0x01 + 0x4E + 0x4A + 0xFF)]
Example: Send an ND command to discover the devices in the PAN.
The frame should look like:
0x7E 0x00 0x04 0x08 0x01 0x4E 0x44 0x64
Where 0x0004 = length
0x08 = AT Command API frame type
0x01 = Frame ID (set to non-zero value)
0x4E44 = AT command ('ND')
0x64 = Checksum
The checksum is calculated as [0xFF - (0x08 + 0x01 + 0x4E + 0x44)]
Example: Send a remote command to the coordinator to set AD1/DIO1 as a digital input (D1=3) and
apply changes to force the IO update.
The API remote command frame should look like:
0x7E 0x00 0x10 0x17 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0xFF 0xFE 0x02 0x44
0x31 0x03 0x70
Where
0x10 = length (16 bytes excluding checksum)
0x17 = Remote Command API frame type
0x01 = Frame ID
0x0000000000000000 = Coordinator's address (can be replaced with coordinator's actual 64-bit
address if known)
0xFFFE = 16- bit Destination Address
0x02 = Apply Changes (Remote Command Options)
0x4431 = AT command ('D1')
0x03 = Command Parameter (the parameter could also be sent as 0x0003 or 0x00000003)
0x70 = Checksum
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API Serial Port Exchanges
AT Commands
The following image shows the API frame exchange that takes place at the serial port when sending an AT
command request to read or set a module parameter. The response can be disabled by setting the frame ID to
0 in the request.
Transmitting and Receiving RF Data
The following image shows the API exchanges that take place at the serial port when sending RF data to another
device. The transmit status frame is always sent at the end of a data transmission unless the frame ID is set to
0 in the transmit request. If the packet cannot be delivered to the destination, the transmit status frame will
indicate the cause of failure. The received data frame (0x90 or 0x91) is set by the AP command.
Remote AT Commands
The following image shows the API frame exchanges that take place at the serial port when sending a remote AT
command. A remote command response frame is not sent out the serial port if the remote device does not
receive the remote command.
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Source Routing
The following image shows the API frame exchanges that take place at the serial port when sending a source
routed transmission.
Supporting the API
Applications that support the API should make provisions to deal with new API frames that may be introduced in
future releases. For example, a section of code on a host microprocessor that handles received serial API frames
(sent out the module's DOUT pin) might look like this:
void XBee_HandleRxAPIFrame(_apiFrameUnion *papiFrame){
switch(papiFrame->api_id){
case RX_RF_DATA_FRAME:
//process received RF data frame
break;
case RX_IO_SAMPLE_FRAME:
//process IO sample frame
break;
case NODE_IDENTIFICATION_FRAME:
//process node identification frame
break;
default:
//Discard any other API frame types that are not being used
break;
API Frames
The following sections illustrate the types of frames encountered while using the API.
AT Command
Frame Type: 0x08
Used to query or set module parameters on the local device. This API command applies changes after executing
the command. (Changes made to module parameters take effect once changes are applied.) The API example
below illustrates an API frame when modifying the NJ parameter value of the module
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Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
P Frame-specific Data Frame Type
Frame ID
AT Command
LSB 2 0x04
3 0x08
4 0x52 (R)
5 0x4E (N)
6 0x4A (J)
Identifies the serial port data frame for the host to
correlate with a subsequent ACK (acknowledgement). If
set to 0, no response is sent.
Command Name - Two ASCII characters that identify the
AT Command.
If present, indicates the requested parameter
value to set the given register.
If no characters present, register is queried.
Parameter Value
(optional)
Checksum
Number of bytes between the length and the checksum
7 0x0D
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
The above example illustrates an AT command when querying an NJ value.
AT Command - Queue Parameter Value
Frame Type: 0x09
This API type allows module parameters to be queried or set. In contrast to the “AT Command” API type, new
parameter values are queued and not applied until either the “AT Command” (0x08) API type or the AC (Apply
Changes) command is issued. Register queries (reading parameter values) are returned immediately.
Example: Send a command to change the baud rate (BD) to 115200 baud, but don't apply
changes yet. (Module will continue to operate at the previous baud rate until changes are applied.)
Frame Fields
Start Delimiter
MSB 1 0x00
P Frame-specific Data Frame Type
Frame ID
AT Command
Parameter Value
(ATBD7 = 115200
baud)
Checksum
Example
Description
0 0x7E
Length
Offset
LSB 2 0x05
Number of bytes between the length and the checksum
3 0x09
4 0x01
5 0x42 (B)
6 0x44 (D)
Identifies the serial port data frame for the host to
correlate with a subsequent ACK (acknowledgement). If
set to 0, no response is sent.
Command Name - Two ASCII characters that identify the
AT Command.
7 0x07
If present, indicates the requested parameter
value to set the given register.
If no characters present, register is queried.
8 0x68
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Note: In this example, the parameter could have been sent as a zero-padded 2-byte or 4-byte value.
ZigBee Transmit Request
Frame Type: 0x10
A Transmit Request API frame causes the module to send data as an RF packet to the specified destination.
The 64-bit destination address should be set to 0x000000000000FFFF for a broadcast transmission (to all
devices). The coordinator can be addressed by either setting the 64-bit address to all 0x00s and the 16-bit
address to 0xFFFE, OR by setting the 64-bit address to the coordinator's 64-bit address and the 16-bit address
to 0x0000. For all other transmissions, setting the 16-bit address to the correct 16-bit address can help improve
performance when transmitting to multiple destinations. If a 16-bit address is not known, this field should be
set to 0xFFFE (unknown). The Transmit Status frame (0x8B) will indicate the discovered 16-bit address, if
successful.
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The broadcast radius can be set from 0 up to NH. If set to 0, the value of NH specifies the broadcast radius
(recommended). This parameter is only used for broadcast transmissions.
The maximum number of payload bytes can be read with the NP command.
Note: if source routing is used, the RF payload will be reduced by two bytes per intermediate hop in the source route.
This example shows if escaping is disabled (AP=1).
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x16
Frame-specific Data Frame Type
Frame ID
Number of bytes between the length and the checksum
3 0x10
4 0x01
Identifies the serial port data frame for the host to
correlate with a subsequent ACK (acknowledgement). If
set to 0, no response is sent.
MSB 5 0x00
6 0x13
64-bit Destination
Address
7 0xA2
8 0x00
9 0x40
10 0x0A
Set to the 64-bit address of the destination device. The
following addresses are also supported:
0x0000000000000000 - Reserved 64-bit address for the
coordinator
0x000000000000FFFF - Broadcast address
11 0x01
LSB 12 0x27
16-bit Destination
Network Address
Broadcast Radius
MSB 13 0xFF
LSB 14 0xFE
15 0x00
Set to the 16-bit address of the destination device, if
known. Set to 0xFFFE if the address is unknown, or if
sending a broadcast.
Sets maximum number of hops a
broadcast transmission can occur.
If set to 0, the broadcast radius will
be set to the maximum hops value.
Bitfield of supported transmission options. Supported
values include the following:
0x01 - Disable retries
0x20 - Enable APS encryption (if EE=1)
0x40 - Use the extended transmission timeout for this
destination
Options
16 0x00
Enabling APS encryption decreases the maximum
number of RF payload bytes by 4 (below the value
reported by NP).
Setting the extended timeout bit causes the stack to set
the extended transmission timeout for the destination
address. (See chapter 4.)
All unused and unsupported bits must be set to 0.
17 0x54
18 0x78
19 0x44
RF Data
20 0x61
21 0x74
Data that is sent to the destination device
22 0x61
23 0x30
24 0x41
Checksum
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25 0x13
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
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XBee®/XBee‐PRO® ZB RF Modules
Example: The example above shows how to send a transmission to a module where escaping is disabled (AP=1)
with destination address 0x0013A200 40014011, payload "TxData1B". If escaping is enabled (AP=2), the frame
should look like:
0x7E 0x00 0x16 0x10 0x01 0x00 0x7D 0x33 0xA2 0x00 0x40 0x0A 0x01 0x27
0xFF 0xFE 0x00 0x00 0x54 0x78 0x44 0x61 0x74 0x61 0x30 0x41 0x7D 0x33
The checksum is calculated (on all non-escaped bytes) as [0xFF - (sum of all bytes from API frame type through
data payload)].
Example: Send a transmission to the coordinator without specifying the coordinator's 64-bit address. The API
transmit request frame should look like:
0x7E 0x00 0x16 0x10 0x01 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0xFF 0xFE 0x00 0x00 0x54
0x78 032 0x43 0x6F 0x6F 0x72 0x64 0xFC
Where 0x16 = length (22 bytes excluding checksum)
0x10 = ZigBee Transmit Request API frame type
0x01 = Frame ID (set to non-zero value)
0x0000000000000000 = Coordinator's address (can be replaced with coordinator's actual 64-bit address
if known
0xFFFE = 16-bit Destination Address
0x00 = Broadcast radius
0x00 = Options
0x547832436F6F7264 = Data payload ("Tx2Coord")
0xFC = Checksum
Explicit Addressing ZigBee Command Frame
Frame Type: 0x11
Allows ZigBee application layer fields (endpoint and cluster ID) to be specified for a data transmission.
Similar to the ZigBee Transmit Request, but also requires ZigBee application layer addressing fields to be
specified (endpoints, cluster ID, profile ID). An Explicit Addressing Request API frame causes the module to
send data as an RF packet to the specified destination, using the specified source and destination endpoints,
cluster ID, and profile ID.
The 64-bit destination address should be set to 0x000000000000FFFF for a broadcast transmission (to all
devices). The coordinator can be addressed by either setting the 64-bit address to all 0x00s and the 16-bit
address to 0xFFFE, OR by setting the 64-bit address to the coordinator's 64-bit address and the 16-bit address
to 0x0000. For all other transmissions, setting the 16-bit address to the correct 16-bit address can help improve
performance when transmitting to multiple destinations. If a 16-bit address is not known, this field should be
set to 0xFFFE (unknown). The Transmit Status frame (0x8B) will indicate the discovered 16-bit address, if
successful.
The broadcast radius can be set from 0 up to NH. If set to 0, the value of NH specifies the broadcast radius
(recommended). This parameter is only used for broadcast transmissions.
The maximum number of payload bytes can be read with the NP command. Note: if source routing is used, the
RF payload will be reduced by two bytes per intermediate hop in the source route.
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Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x1A
Frame-specific Data Frame Type
Frame ID
Number of bytes between the length and the checksum
3 0x11
4 0x01
Identifies the serial port data frame for the host to
correlate with a subsequent ACK (acknowledgement). If
set to 0, no response is sent.
MSB 5 0x00
6 0x00
64-bit Destination
Address
7 0x00
8 0x00
9 0x00
10 0x00
Set to the 64-bit address of the destination device. The
following addresses are also supported:
0x0000000000000000 - Reserved 64-bit address for the
coordinator
0x000000000000FFFF - Broadcast address
11 0x00
12 0x00
16-bit Destination
Network Address
Source Endpoint
Destination Endpoint
Cluster ID
Profile ID
Broadcast Radius
MSB 13 0xFF
LSB 14 0xFE
Set to the 16-bit address of the destination device, if
known. Set to 0xFFFE if the address is unknown, or if
sending a broadcast.
15 0xA0
Source endpoint for the transmission.
16 0xA1
Destination endpoint for the
transmission.
17 0x15
18 0x54
19 0xC1
20 0x05
21 0x00
Cluster ID used in the transmission
Profile ID used in the transmission
Sets the maximum number of hops a broadcast
transmission can traverse. If set to 0, the transmission
radius will be set to the network maximum hops value.
Bitfield of supported transmission options. Supported
values include the following:
0x01 - Disable retries
0x04- Indirect Addressing
0x08- Multicast Addressing
0x20 - Enable APS encryption (if EE=1)
0x40 - Use the extended transmission timeout for this
destination
Transmit Options
22 0x00
Enabling APS encryption decreases the maximum
number of RF payload bytes by 4 (below the value
reported by NP).
Setting the extended timeout bit causes the stack to set
the extended transmission timeout for the destination
address. (See chapter 4.)
All unused and unsupported bits must be set to 0.
23 0x54
24 0x78
Data Payload
25 0x44
26 0x61
Data that is sent to the destination device
27 0x74
28 0x61
Checksum
29 0x3A
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Send a data transmission to the coordinator (64-bit address of 0x00s) using a source endpoint
of 0xA0, destination endpoint 0xA1, cluster ID =0x1554, and profile ID 0xC105. Payload will be "TxData".
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Remote AT Command Request
Frame Type: 0x17
Used to query or set module parameters on a remote device. For parameter changes on the remote device to
take effect, changes must be applied, either by setting the apply changes options bit, or by sending an AC
command to the remote.
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x10
Frame-specific Data Frame Type
Frame ID
Number of bytes between the length and the checksum
3 0x17
4 0x01
Identifies the serial port data frame for the host to
correlate with a subsequent ACK (acknowledgement). If
set to 0, no response is sent.
MSB 5 0x00
6 0x13
64-bit Destination
Address
7 0xA2
8 0x00
9 0x40
10 0x40
Set to the 64-bit address of the destination device. The
following addresses are also supported:
0x0000000000000000 - Reserved 64-bit address for the
coordinator
0x000000000000FFFF - Broadcast address
11 0x11
LSB 12 0x22
16-bit Destination
Network Address
Remote Command
Options
AT Command
Command Parameter
Checksum
MSB 13 0xFF
LSB 14 0xFE
Set to the 16-bit address of the destination device, if
known. Set to 0xFFFE if the address is unknown, or if
sending a broadcast.
Bitfield to enable various remote command options.
Supported values include:
0x01 - Disable ACK
0x02 - Apply changes on remote. (If
not set, AC command must be sent
0x02 (apply before changes will take effect.)
15
changes)
0x40 - Use the extended transmission timeout for this
destination.
Setting the extended timeout bit causes the stack to set
the extended transmission timeout for the destination
address (see chapter 4).
All unused and unsupported bits must be set to 0.
16 0x42 (B)
17 0x48 (H)
Name of the
command
18 0x01
If present, indicates the requested
parameter value to set the given
register. If no characters present,
the register is queried.
19 0xF5
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Send a remote command to change the broadcast hops register on a remote device to 1 (broadcasts go to 1-hop neighbors only), and apply changes so the new configuration value immediately takes
effect. In this example, the 64-bit address of the remote is 0x0013A200 40401122, and the destination 16bit address is unknown.
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XBee®/XBee‐PRO® ZB RF Modules
Create Source Route
Frame Type: 0x21
This frame creates a source route in the module. A source route specifies the complete route a packet should
traverse to get from source to destination. Source routing should be used with many-to-one routing for best
results.
Note: Both the 64-bit and 16-bit destination addresses are required when creating a source route. These are
obtained when a Route Record Indicator (0xA1) frame is received.
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x14
Frame-specific Data Frame Type
Frame ID
Number of bytes between the length and the checksum
3 0x21
4 0x00
The Frame ID should always be set to 0.
MSB 5 0x00
6 0x13
64-bit Destination
Address
7 0xA2
8 0x00
9 0x40
10 0x40
Set to the 64-bit address of the destination device. The
following addresses are also supported:
0x0000000000000000 - Reserved 64-bit address for the
coordinator
0x000000000000FFFF - Broadcast address
11 0x11
LSB 12 0x22
16-bit Destination
Network Address
Route Command
Options
Number of Addresses
Address 1
Address 2 (closer hop
MSB 13 0x33
LSB 14 0x44
15 0x00
Set to 0.
16 0x03
The number of addresses in the
source route (excluding source
and destination). If this number is 0 or greater than the
source route table size (40), this API frame will be silently
discarded. However, there is no use in including more
than 11 intermediate hops because a frame with more
hops than that will be discarded.
17 0xEE
18 0xFF
19 0xCC
20 0xDD
Address 3
Checksum
Set to the 16-bit address of the destination device, if
known. Set to 0xFFFE if the address is unknown, or if
sending a broadcast.
21 0xAA
22 0xBB
23 0x01
(neighbor of
destination)
Address of intermediate hop
(neighbor of source)
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Intermediate hop addresses must be ordered starting with the neighbor of the destination, and
working closer to the source. For example, suppose a route is found between A and E as shown below.
A'B'C'D'E
If device E has the 64-bit and 16-bit addresses of 0x0013A200 40401122 and 0x3344, and if devices B, C, and
D have the following 16-bit addresses:
B = 0xAABB
C = 0xCCDD
D = 0xEEFF
The example above shows how to send the Create Source Route frame to establish a source route between A
and E.
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XBee®/XBee‐PRO® ZB RF Modules
AT Command Response
Frame Type: 0x88
In response to an AT Command message, the module will send an AT Command Response message. Some
commands will send back multiple frames (for example, the ND (Node Discover) command).
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x05
Frame Type
3 0x88
Frame ID
4 0x01
AT Command
a Frame-specific Data
Command Status
5 ‘B’ = 0x42
6 ‘D’ = 0x44
7 0x00
Identifies the serial port data frame being reported. Note:
If Frame ID = 0 in AT Command Mode, no AT Command
Response will be given.
Command Name - Two ASCII characters that identify the
AT Command.
0 = OK
1 = ERROR
2 = Invalid Command
3 = Invalid Parameter
4 = Tx Failure
Register data in binary format. If the register was set,
then this field is not returned, as in this example.
Command Data
Checksum
Number of bytes between the length and the checksum
8 0xF0
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Suppose the BD parameter is changed on the local device with a frame ID of 0x01. If successful
(parameter was valid), the above response would be received.
Modem Status
Frame Type: (0x8A)
RF module status messages are sent from the module in response to specific conditions.
Example: The following API frame is returned when an API coordinator forms a network.
Frame Fields
Start Delimiter
MSB 1 0x00
LSB 2 0x02
Frame Type
t Checksum
Example
Description
0 0x7E
Length
I Frame-specific Data
Offset
Status
Number of bytes between the length and the checksum
3 0x8A
4 0x06
0 = Hardware reset
1 = Watchdog timer reset
2 =Joined network (routers and end devices)
3 =Disassociated
6 =Coordinator started
7 = Network security key was updated
0x0D = Voltage supply limit exceeded (PRO only)
0x11 = Modem configuration changed while join in
progress
0x80+ = Ember ZigBee stack error
5 0x6F
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Note: New modem status codes may be added in future firmware releases.
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XBee®/XBee‐PRO® ZB RF Modules
ZigBee Transmit Status
Frame Type: 0x8B
When a TX Request is completed, the module sends a TX Status message. This message will indicate if the
packet was transmitted successfully or if there was a failure.
Frame Fields
Start Delimiter
Offset
Example
Length
MSB 1 0x00
LSB 2 0x07
Number of bytes between the length and the checksum
Frame Type
3 0x8B
Frame ID
4 0x01
16-bit address of
destination
5 0x7D
Transmit Retry Count
7 0x00
The number of application transmission retries that took
place.
8 0x00
0x00 = Success
0x01 = MAC ACK Failure
0x02 = CCA Failure
0x15 = Invalid destination endpoint
0x21 = Network ACK Failure
0x22 = Not Joined to Network
0x23 = Self-addressed
0x24 = Address Not Found
0x25 = Route Not Found
0x26 = Broadcast source failed to hear a neighbor relay
the message
0x2B = Invalid binding table index
0x2C = Resource error lack of free buffers, timers, etc.
0x2D = Attempted broadcast with APS transmission
0x2E = Attempted unicast with APS transmission, but
EE=0
0x32 = Resource error lack of free buffers, timers, etc.
0x74 = Data payload too large
0x75 = Indirect message unrequested
9 0x01
0x00 = No Discovery Overhead
0x01 = Address Discovery
0x02 = Route Discovery
0x03 = Address and Route
0x40 = Extended Timeout Discovery
6 0x84
a Frame-specific Data
Delivery Status
Discovery Status
Checksum
Description
0 0x7E
10 0x71
Identifies the serial port data frame being reported. Note:
If Frame ID = 0 in AT Command Mode, no AT Command
Response will be given.
16-bit Network Address the packet was delivered to (if
successful). If not successful, this address will be
0xFFFD: Destination Address Unknown.
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Suppose a unicast data transmission was sent to a destination device with a 16-bit address of
0x7D84. (The transmission could have been sent with the 16-bit address set to 0x7D84 or 0xFFFE.)
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XBee®/XBee‐PRO® ZB RF Modules
ZigBee Receive Packet
Frame Type: (0x90)
When the module receives an RF packet, it is sent out the serial port using this message type.
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x11
Frame Type
Number of bytes between the length and the checksum
3 0x90
MSB 4 0x00
5 0x13
64-bit Source
Address
6 0xA2
7 0x00
8 0x40
9 0x52
64-bit address of sender. Set to 0xFFFFFFFFFFFFFFFF
(unknown 64-bit address) if the sender's 64-bit address is
unknown.
10 0x2B
LSB 11 0xAA
16-bit Source
Network Address
a Frame-specific Data
Receive Options
MSB 12 0x7D
LSB 13 0x84
14 0x01
16-bit address of sender
0x01 - Packet Acknowledged
0x02 - Packet was a broadcast packet
0x20 - Packet encrypted with APS encryption
0x40 - Packet was sent from an end device (if known)
Note: Option values can be combined. For example, a
0x40 and a 0x01 will show as a 0x41.
Other possible values 0x00, 0x21, 0x22, 0x41, 0x42,
0x60, 0x61, 0x62.
15 0x52
16 0x78
Received Data
17 0x44
18 0x61
Received RF data
19 0x74
20 0x61
Checksum
21 0x0D
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Suppose a device with a 64-bit address of 0x0013A200 40522BAA, and 16-bit address 0x7D84
sends a unicast data transmission to a remote device with payload "RxData". If AO=0 on the receiving
device, it would send the above example frame out its serial port.
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XBee®/XBee‐PRO® ZB RF Modules
ZigBee Explicit Rx Indicator
Frame Type:0x91
When the modem receives a ZigBee RF packet it is sent out the serial port using this message type (when
AO=1).
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
Number of bytes between the length and the checksum
LSB 2 0x18
Frame Type
3 0x91
MSB 4 0x00
5 0x13
64-bit Source
Address
6 0xA2
7 0x00
8 0x40
64-bit address of sender. Set to 0xFFFFFFFFFFFFFFFF
(unknown 64-bit address) if the sender's 64-bit address is
unknown.
9 0x52
10 0x2B
LSB 11 0xAA
16-bit Source
Network Address
MSB 12 0x7D
Source Endpoint
14 0xE0
Endpoint of the source that initiated the
transmission
15 0xE0
Endpoint of the destination the message is
addressed to.
c Frame-specific Data Destination Endpoint
Cluster ID
Profile ID
Receive Options
LSB 13 0x84
16 0x22
17 0x11
18 0xC1
19 0x05
20 0x02
16-bit address of sender.
Cluster ID the packet was addressed
to.
Profile ID the packet was
addressed to.
0x01 – Packet Acknowledged
0x02 – Packet was a broadcast packet
0x20 - Packet encrypted with APS encryption
0x40 - Packet was sent from an end device (if known)
21 0x52
22 0x78
Received Data
23 0x44
24 0x61
Received RF data
25 0x74
26 0x61
Checksum
27 0x52
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Suppose a device with a 64-bit address of 0x0013A200 40522BAA, and 16-bit address 0x7D84
sends a broadcast data transmission to a remote device with payload "RxData". Suppose the transmission
was sent with source and destination endpoints of 0xE0, cluster ID=0x2211, and profile ID=0xC105. If
AO=1 on the receiving device, it would send the above frame out its serial port.
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XBee®/XBee‐PRO® ZB RF Modules
ZigBee IO Data Sample Rx Indicator
Frame Type: 0x92
When the module receives an I/O sample frame from a remote device, it sends the sample out the serial port
using this frame type (when AO=0). Only modules running in API mode will send I/O samples out the serial
port.
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
Number of bytes between the length and the checksum
LSB 2 0x14
Frame Type
3 0x92
MSB 4 0x00
5 0x13
64-bit Source
Address
6 0xA2
7 0x00
8 0x40
64-bit address of sender
9 0x52
10 0x2B
LSB 11 0xAA
16-bit Source
Network Address
Receive Options
Number of Samples
a Frame-specific Data
Digital Channel Mask*
Analog Channel
Mask**
MSB 12 0x7D
LSB 13 0x84
14 0x01
0x01 - Packet Acknowledged
0x02 - Packet was a broadcast packet
15 0x01
Number of sample sets
included in the payload.
(Always set to 1)
16 0x00
17 0x1C
18 0x02
19 0x00
Digital Samples (if
included)
20 0x14
21 0x02
Analog Sample
Checksum
Š 2014 Digi International Inc.
16-bit address of sender.
22 0x25
23 0xF5
Bitmask field that indicates
which digital IO lines on the
remote have sampling
enabled (if any).
Bitmask field that indicates
which analog IO lines on the
remote have sampling
enabled (if any).
If the sample set includes any digital IO lines
(Digital Channel Mask > 0), these two bytes
contain samples for all enabled digital IO lines.
DIO lines that do not have sampling enabled
return 0. Bits in these 2 bytes map the same as
they do in the Digital Channels Mask field.
If the sample set includes any analog input lines
(Analog Channel Mask > 0), each enabled analog input
returns a 2-byte value indicating the A/D measurement
of that input. Analog samples are ordered sequentially
from AD0/DIO0 to AD3/DIO3, to the supply voltage.
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
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**
N/A
N/A
N/A
CD/DIO
12
CTS/DI RTS/DI ASSOC/ DIO4
O7
O6
DIO5
PWM/DI RSSI/DI N/A
N/A
O11
O10
AD3/DI AD2/DI AD1/DI AD0/DI
O3
O2
O1
O0
Supply
Voltage
N/A
N/A
AD3
N/A
AD2
AD1
AD0
Example: Suppose an IO sample is received with analog and digital IO, from a remote with a 64-bit
address of 0x0013A200 40522BAA and a 16-bit address of 0x7D84. If pin AD1/DIO1 is enabled as an
analog input, AD2/DIO2 and DIO4 are enabled as a digital inputs (currently high), and AD3/DIO3 is
enabled as a digital output (low) the IO sample is shown in the API example in the table above.
XBee Sensor Read Indicator
Frame Type: 0x94
When the module receives a sensor sample (from a Digi 1-wire sensor adapter), it is sent out the serial port
using this message type (when AO=0).
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
Number of bytes between the length and the checksum
LSB 2 0x17
Frame Type
3 0x94
MSB 4 0x00
5 0x13
64-bit Source
Address
6 0xA2
7 0x00
8 0x40
64-bit address of sender
9 0x52
10 0x2B
LSB 11 0xAA
16-bit Source
Network Address
Receive Options
a Frame-specific Data
1-Wire
Sensors
MSB 12 0xDD
LSB 13 0x6C
16-bit address of sender.
14 0x01
0x01 - Packet Acknowledged
0x02 - Packet was a broadcast packet
15 0x03
0x01 = A/D Sensor Read
0x02 = Temperature Sensor Read
0x60 = Water present (module CD pin low)
16 0x00
17 0x02
18 0x00
A/D Values
19 0xCE
20 0x00
21 0xEA
Indicates a two-byte value for each of four A/D sensors
(A, B, C, D)
Set to 0xFFFFFFFFFFFFFFFF if no A/Ds are found.
22 0x00
23 0x52
Temperature
Read
24 0x01
25 0x6A
Checksum
Š 2014 Digi International Inc.
26 0x8B
Indicates the two-byte value read from a digital
thermometer if present. Set to 0xFFFF if not found.
0xFF - the 0x8 bit sum of bytes from offset 3 to this byte.
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XBee®/XBee‐PRO® ZB RF Modules
Example: Suppose a 1-wire sensor sample is received from a device with a 64-bit address of 0x0013A200
40522BAA and a 16-bit address of 0xDD6C. If the sensor sample was taken from a 1-wire humidity sensor,
the API frame could look like this (if AO=0):
For convenience, let's label the A/D and temperature readings as AD0, AD1, AD2, AD3, and T. Using the data in
this example:
AD0 = 0x0002
AD1 = 0x00CE
AD2 = 0x00EA
AD3 = 0x0052
T = 0x016A
To convert these to temperature and humidity values, the following equations should be used.
Temperature (°C) = (T / 16), for T < 2048
= - (T & 0x7FF) / 16, for T >= 2048
Vsupply = (AD2 * 5.1) / 255
Voutput = (AD3 * 5.1) / 255
Relative Humidity = ((Voutput / Vsupply) - 0.16) / (0.0062)
True Humidity = Relative Humidity / (1.0546 - (0.00216 * Temperature (°C)))
Looking at the sample data, we have:
Vsupply = (234 * 5.1 / 255) = 4.68
Voutput = (82 * 5.1 / 255) = 1.64
Temperature = (362 / 16) = 22.625°C
Relative H = (161.2903 * ((1.64/4.68) - 0.16)) = 161.2903 * (0.19043) = 30.71%
True H = (30.71 / (1.0546 - (0.00216 * 22.625))) = (30.71 / 1.00573) = 30.54%
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Node Identification Indicator
Frame Type: 0x95
This frame is received when a module transmits a node identification message to identify itself (when AO=0).
The data portion of this frame is similar to a network discovery response frame (see ND command).
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
Number of bytes between the length and the checksum
LSB 2 0x20
Frame Type
3 0x95
MSB 4 0x00
5 0x13
64-bit Source
Address
6 0xA2
7 0x00
8 0x40
64-bit address of sender
9 0x52
10 0x2B
LSB 11 0xAA
16-bit Source
Network Address
Frame-specific Data
MSB 12 0x7D
LSB 13 0x84
Receive Options
14 0x02
Source 16-bit
address
15 0x7D
16 0x84
16-bit address of sender.
0x01 - Packet Acknowledged
0x02 - Packet was a broadcast packet
Set to the 16-bit network address of the remote. Set to
0xFFFE if unknown.
17 0x00
18 0x13
19 0xA2
64-bit Network
address
20 0x00
21 0x40
Indicates the 64-bit address of the remote module that
transmitted the node identification frame.
22 0x52
23 0x2B
24 0xAA
NI String
25 0x20
26 0x00
Parent 16-bit
address
27 0xFF
Device Type
29 0x01
0 = Coordinator
1 = Router
2 = End Device
30 0x01
1 = Frame sent by node identification pushbutton event
(see D0 command)
2 = Frame sent after joining event occurred (see JN
command).
3 = Frame sent after power cycle event occurred (see JN
command).
Source Event
Digi Profile ID
Manufacturer ID
Checksum
Node identifier string on the remote device. The NI-String
is terminated with a NULL byte (0x00).
28 0xFE
31 0xC1
32 0x05
33 0x10
34 0x1E
35 0x1B
Indicates the 16-bit address of the remote's parent or
0xFFFE if the remote has no parent.
Set to Digi's application profile ID.
Set to Digi's Manufacturer ID.
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: If the commissioning push button is pressed on a remote router device with 64-bit address
0x0013A200 40522BAA, 16-bit address 0x7D84, and default NI string, the following node identification
indicator would be received.
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XBee®/XBee‐PRO® ZB RF Modules
Remote Command Response
Frame Type: 0x97
If a module receives a remote command response RF data frame in response to a Remote AT Command
Request, the module will send a Remote AT Command Response message out the serial port. Some commands
may send back multiple frames--for example, Node Discover (ND) command.
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
MSB 1 0x00
Length
LSB 2 0x13
Frame Type
3 0x97
Frame ID
4 0x55
Number of bytes between the length and the checksum
This is the same value passed in to the request.
MSB 5 0x00
6 0x13
7 0xA2
64-bit Source
(remote) Address
8 0x00
9 0x40
The address of the remote radio returning this response.
10 0x52
11 0x2B
c Frame-specific Data 16-bit Source
(remote) Address
AT Commands
Command Status
LSB 12 0xAA
MSB 13 0x7D
LSB 14 0x84
15 0x53
16 0x4C
17 0x00
Set to the 16-bit network
address of the remote.
Set to 0xFFFE if
unknown.
Name of the command
0 = OK
1 = ERROR
2 = Invalid Command
3 = Invalid Parameter
4 = Remote Command Transmission Failed
18 0x40
Command Data
19 0x52
20 0x2B
Register data in binary format. If the register was set,
then this field is not returned.
21 0xAA
Checksum
22 0xF0
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: If a remote command is sent to a remote device with 64-bit address 0x0013A200 40522BAA and
16-bit address 0x7D84 to query the SL command, and if the frame ID=0x55, the response is shown in the
example API frame in the table above.
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Over-the-Air Firmware Update Status
Frame Type: 0xA0
The Over-the-Air Firmware Update Status frame provides a status indication of a firmware update transmission
attempt. If a query command (0x01 0x51) is sent to a target with a 64-bit address of 0x0013A200 40522BAA
through an updater with 64-bit address 0x0013A200403E0750 and 16-bit address 0x0000, the following is the
expected response.
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
MSB 1 0x00
Length
LSB 2 0x16
Frame Type
Number of bytes between the length and the checksum
3 0xA0
MSB 4 0x00
5 0x13
6 0xA2
64-bit Source
(remote) Address
7 0x00
8 0x40
The address of the remote radio returning this response.
9 0x3E
10 0x07
LSB 11 0x50
16-bit Destination
Address
Receive Options
a Frame-specific Data
Bootloader Message
Type
Block Number
12 0x00
13 0x00
16-bit address of the updater device
14 0x01
0x01 - Packet Acknowledged.
0x02 - Packet was a broadcast.
15 0x52
0x06 - ACK
0x15 - NACK
0x40 - No Mac ACK
0x51 - Query (received if the bootloader is not active on
the target)
0x52 - Query Response
16 0x00
Block number used in the update request. Set to 0 if not
applicable.
17 0x00
18 0x13
19 0xA2
64-bit Target Address
20 0x00
21 0x40
64-bit Address of remote device that is being updated
(target).
22 0x52
23 0x2B
24 0xAA
Checksum
25 0x66
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
If a query request returns a 0x15 (NACK) status, the target is likely waiting for a firmware update image. If no
messages are sent to it for about 75 seconds, the target will timeout and accept new query messages.
If a query returns a 0x51 (QUERY) status, then the target's bootloader is not active and will not respond to
query messages.
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XBee®/XBee‐PRO® ZB RF Modules
Route Record Indicator
Frame Type: 0xA1
The route record indicator is received whenever a device sends a ZigBee route record command. This is used
with many-to-one routing to create source routes for devices in a network.
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x13
Frame Type
Number of bytes between the length and the checksum
3 0xA1
MSB 4 0x00
5 0x13
64-bit Source
Address
6 0xA2
7 0x00
8 0x40
64-bit address of the device that
initiated the route record.
9 0x40
10 0x11
LSB 11 0x22
Source (updater)
c Frame-specific Data 16-bit Address
Receive Options
Number of Addresses
Address 1
Address 2 (closer hop
Address n (neighbor
of source)
Checksum
12 0x33
13 0x44
16-bit address of the
device that initiated the
route record.
14 0x01
0x01 - Packet Acknowledged.
0x02 - Packet was a broadcast.
15 0x03
The number of addresses in the
source route (excluding source
and destination).
16 0xEE
17 0xFF
18 0xCC
19 0xDD
20 0xAA
21 0xBB
22 0x80
(neighbor of
destination)
Address of intermediate hop
Two bytes per 16-bit address.
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Suppose device E sends a route record that traverses multiple hops en route to data collector
device A as shown below.
A B C D E
If device E has the 64-bit and 16-bit addresses of 0x0013A200 40401122 and 0x3344, and if devices B, C, and
D have the following 16-bit addresses:
B = 0xAABB
C = 0xCCDD
D = 0xEEFF
The data collector will send the above API frame out its serial port.
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Many-to-One Route Request Indicator
Frame Type: 0xA3
The many-to-one route request indicator frame is sent out the serial port whenever a many-to-one route
request is received
Frame Fields
Start Delimiter
Offset
Example
Description
0 0x7E
MSB 1 0x00
Length
LSB 2 0x0C
Frame Type
Number of bytes between the length and the checksum
3 0xA3
MSB 4 0x00
5 0x13
c Frame-specific Data
64-bit Source
Address
7 0x00
8 0x40
64-bit address of the device that sent the many-to-one
route request
9 0x40
10 0x11
LSB 11 0x22
Source 16-bit Address
Reserved
Checksum
6 0xA2
MSB 12 0x00
LSB 13 0x00
16-bit address of the device that initiated the many-to-one
route request.
14 0x00
Set to 0.
15 0xF4
0xFF - the 8 bit sum of bytes from offset 3 to this byte.
Example: Suppose a device with a 64-bit address of 0x0013A200 40401122 and 16-bit address of 0x0000
sends a many-to-one route request. All remote routers operating in API mode that receive the many-to-one
broadcast would send the above example API frame out their serial port.
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XBee®/XBee‐PRO® ZB RF Modules
Sending ZigBee Device Objects (ZDO) Commands with the API
ZigBee Device Objects (ZDOs) are defined in the ZigBee Specification as part of the ZigBee Device Profile. These
objects provide functionality to manage and map out the ZigBee network and to discover services on ZigBee
devices. ZDOs are typically required when developing a ZigBee product that will interoperate in a public profile such
as home automation or smart energy, or when communicating with ZigBee devices from other vendors. The ZDO
can also be used to perform several management functions such as frequency agility (energy detect and channel
changes - Mgmt Network Update Request), discovering routes (Mgmt Routing Request) and neighbors (Mgmt LQI
Request), and managing device connectivity (Mgmt Leave and Permit Join Request).
The following table shows some of the more prominent ZDOs with their respective cluster identifier. Each ZDO
command has a defined payload. See the "ZigBee Device Profile" section of the ZigBee Specification for details.
ZDO Command
Network Address Request
Cluster ID
0x0000
IEEE Address Request
0x0001
Node Descriptor Request
0x0002
Simple Descriptor Request
0x0004
Active Endpoints Request
0x0005
Match Descriptor Request
0x0006
Mgmt LQI Request
0x0031
Mgmt Routing Request
0x0032
Mgmt Leave Request
0x0034
Mgmt Permit Joining Request
0x0036
Mgmt Network Update Request
0x0038
The Explicit Transmit API frame (0x11) is used to send ZigBee Device Objects commands to devices in the network.
Sending ZDO commands with the Explicit Transmit API frame requires some formatting of the data payload field.
When sending a ZDO command with the API, all multiple byte values in the ZDO command (API payload) (e.g. u16,
u32, 64-bit addresses) must be sent in little endian byte order for the command to be executed correctly on a
remote device.
For an API XBee to receive ZDO responses, the AO command must be set to 1 to enable the explicit receive API
frame.
The following table shows how the Explicit API frame can be used to send an "Active Endpoints" request to discover
the active endpoints on a device with a 16-bit address of 0x1234.
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XBee®/XBee‐PRO® ZB RF Modules
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x17
Frame Type
3 0x11
Frame ID
4 0x01
Number of bytes between the length and the checksum
Identifies the serial port data frame for the host to
correlate with a subsequent transmit status. If set to 0, no
transmit status frame will be sent out the serial port.
MSB 5 0x00
6 0x00
7 0x00
64-bit Destination
Address
8 0x00
9 0x00
10 0x00
64-bit address of the destination device (big endian byte
order). For unicast transmissions, set to the 64-bit
address of the destination device, or to
0x0000000000000000 to send a unicast to the
coordinator. Set to 0x000000000000FFFF for broadcast.
11 0xFF
12 0xFF
MSB 13 0xFF
16-bit Destination
Network Address
LSB 14 0xFE
Source Endpoint
a Frame-specific Data
Destination Endpoint
Cluster ID
Set to 0x00 for ZDO transmissions (endpoint 0 is the
ZDO endpoint).
16 0x00
Set to 0x00 for ZDO transmissions (endpoint 0 is the
ZDO endpoint).
LSB 18 0x05
MSB 19 0x00
LSB 20 0x00
Broadcast Radius
Transmit Options
Data Payload
15 0x00
MSB 17 0x00
Profile ID
Š 2014 Digi International Inc.
Set to the cluster ID that corresponds to the ZDO
command being sent.
0x0005 = Active Endpoints Request
Set to 0x0000 for ZDO transmissions (Profile ID 0x0000
is the ZigBee Device Profile that supports ZDOs).
21 0x00
Sets the maximum number of hops a broadcast
transmission can traverse. If set to 0, the transmission
radius will be set to the network maximum hops value.
22 0x00
All bits must be set to 0.
Transaction Sequence
Number
23 0x01
ZDO Payload
24 0x34
25 0x12
Checksum
16-bit address of the destination device (big endian byte
order). Set to 0xFFFE for broadcast, or if the 16-bit
address is unknown.
26 0xA6
The required payload for a ZDO command. All multi-byte
ZDO parameter values (u16, u32, 64-bit address) must
be sent in little endian byte order.
The Active Endpoints Request includes the following
payload:
[16-bit NwkAddrOfInterest]
Note the 16-bit address in the API example (0x1234) is
sent in little endian byte order (0x3412).
0xFF minus the 8 bit sum of bytes from offset 3 to this
byte.
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Sending ZigBee Cluster Library (ZCL) Commands with the API
The ZigBee Cluster Library defines a set of attributes and commands (clusters) that can be supported in multiple
ZigBee profiles. The ZCL commands are typically required when developing a ZigBee product that will interoperate in
a public profile such as home automation or smart energy, or when communicating with ZigBee devices from other
vendors. Applications that are not designed for a public profile or for interoperability applications can skip this
section.
The following table shows some prominent clusters with their respective attributes and commands.
Cluster (Cluster ID)
Attributes (Attribute ID)
Cluster ID
Basic (0x0000)
Application Version (0x0001)
Hardware Version (0x0003)
Model Identifier (0x0005)
-Reset to defaults
(0x00)
Identify (0x0003)
Identify Time (0x0000)
Identify (0x00)
Identify Query (0x01)
Time (0x000A)
Time (0x0000)
Time Status (0x0001)
Time Zone (0x0002)
Thermostat (0x0201)
Local Temperature (0x0000)
Occupancy (0x0002)
-Setpoint raise / lower
(0x00)
The ZCL defines a number of profile-wide commands that can be supported on any profile, also known as general
commands. These commands include the following.
Command (Command ID)
Description
Read Attributes (0x00)
Used to read one or
more attributes on a
remote device.
Read Attributes Response (0x01)
Generated in
response to a read
attributes command.
Write Attributes (0x02)
Used to change one
or more attributes on
a remote device.
Write Attributes Response (0x04)
Sent in response to a
write attributes
command.
Configure Reporting (0x06)
Used to configure a
device to
automatically report
on the values of one
or more of its
attributes.
Report Attributes (0x0A)
Used to report
attributes when report
conditions have been
satisfied.
Discover Attributes (0x0C)
Used to discover the
attribute identifiers on
a remote device.
Discover Attributes Response (0x0D)
Sent in response to a
discover attributes
command.
The Explicit Transmit API frame (0x11) is used to send ZCL commands to devices in the network. Sending ZCL
commands with the Explicit Transmit API frame requires some formatting of the data payload field.
When sending a ZCL command with the API, all multiple byte values in the ZCL command (API Payload) (e.g. u16,
u32, 64-bit addresses) must be sent in little endian byte order for the command to be executed correctly on a
remote device.
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XBee®/XBee‐PRO® ZB RF Modules
Note: When sending ZCL commands, the AO command should be set to 1 to enable the explicit receive API frame. This
will provide indication of the source 64- and 16-bit addresses, cluster ID, profile ID, and endpoint information for each
received packet. This information is required to properly decode received data.
The following table shows how the Explicit API frame can be used to read the hardware version attribute from a
device with a 64-bit address of 0x0013A200 40401234 (unknown 16-bit address). This example uses arbitrary
source and destination endpoints. Recall the hardware version attribute (attribute ID 0x0003) is part of the basic
cluster (cluster ID 0x0000). The Read Attribute general command ID is 0x00.
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x19
Frame Type
3 0x11
Frame ID
4 0x01
Number of bytes between the length and the checksum
Identifies the serial port data frame for the host to
correlate with a subsequent transmit status. If set to 0, no
transmit status frame will be sent out the serial port.
MSB 5 0x00
6 0x13
7 0xA2
64-bit
Destination
Address
8 0x00
9 0x40
10 0x40
64-bit address of the destination device (big endian byte
order). For unicast transmissions, set to the 64-bit
address of the destination device, or to
0x0000000000000000 to send a unicast to the
coordinator. Set to 0x000000000000FFFF for broadcast.
11 0x12
12 0x34
16-bit
Destination
Network
Address
MSB 13 0xFF
LSB 14 0xFE
16-bit address of the destination device (big endian byte
order). Set to 0xFFFE for broadcast, or if the 16-bit
address is unknown.
Source
Endpoint
15 0x41
Set to the source endpoint on the sending device. (0x41
arbitrarily selected).
Destination
Endpoint
16 0x42
Set to the destination endpoint on the remote device.
(0x42 arbitrarily selected)
MSB 17 0x00
P Frame-specific
Cluster ID
a Data
Profile ID
LSB 18 0x00
MSB 19 0xD1
LSB 20 0x23
Set to the cluster ID that corresponds to the ZCL
command being sent.
0x0000 = Basic Cluster
Set to the profile ID supported on the device. (0xD123
arbitrarily selected).
Broadcast
Radius
21 0x00
Sets the maximum number of hops a broadcast
transmission can traverse. If set to 0, the transmission
radius will be set to the network maximum hops value.
Transmit
Options
22 0x00
All bits must be set to 0.
Frame Control
23 0x00
Bitfield that defines the command type and other relevant
information in the ZCL command. See the ZCL
specification for details.
Transaction
Sequence
Number
24 0x01
A sequence number used to correlate a ZCL command
with a ZCL response. (The hardware version response
will include this byte as a sequence number in the
response.) The value 0x01 was arbitrarily selected.
Command ID
25 0x00
Since the frame control "frame type" bits are 00, this byte
specifies a general command. Command ID 0x00 is a
Read Attributes command.
Attribute ID
26 0x03
Data Payload
ZCL Frame
Header
ZCL Payload
27 0x00
Checksum
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28 0xFA
The payload for a "Read Attributes" command is a list of
Attribute Identifiers that are being read.
Note the 16-bit Attribute ID (0x0003) is sent in little
endian byte order (0x0300). All multi-byte ZCL header
and payload values must be sent in little endian byte
order.
0xFF minus the 8 bit sum of bytes from offset 3 to this
byte.
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XBee®/XBee‐PRO® ZB RF Modules
In the above example, the Frame Control field (offset 23) was constructed as follows:
Name
Bits Example Value Description
Frame Type
0-1
00 - Command acts across the entire profile
Manufacturer Specific
0 - The manufacturer code field is omitted from the ZCL Frame Header.
Direction
0 - The command is being sent from the client side to the server side.
Disable Default Response
0 - Default response not disabled
Reserved
5-7
Set to 0.
See the ZigBee Cluster Library specification for details.
Sending Public Profile Commands with the API
Commands in public profiles such as Smart Energy and Home Automation can be sent with the XBee API using the
Explicit Transmit API frame (0x11). Sending public profile commands with the Explicit Transmit API frame requires
some formatting of the data payload field. Most of the public profile commands fit into the ZigBee Cluster Library
(ZCL) architecture as described in the previous section.
The following table shows how the Explicit API frame can be used to send a demand response and load control
message (cluster ID 0x701) in the smart energy profile (profile ID 0x0109) in the revision 14 Smart Energy
specification. The message will be a "Load Control Event" (command ID 0x00) and will be sent to a device with 64bit address of 0x0013A200 40401234 with a 16-bit address of 0x5678. The event will start a load control event for
water heaters and smart appliances, for a duration of 1 minute, starting immediately.
Note: When sending public profile commands, the AO command should be set to 1 to enable the explicit receive API
frame. This will provide indication of the source 64- and 16-bit addresses, cluster ID, profile ID, and endpoint information for each received packet. This information is required to properly decode received data.
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XBee®/XBee‐PRO® ZB RF Modules
Frame Fields
Offset
Start Delimiter
Example
Description
0 0x7E
Length
MSB 1 0x00
LSB 2 0x19
Frame Type
3 0x11
Frame ID
4 0x01
Number of bytes between the length and the checksum
Identifies the serial port data frame for the host to
correlate with a subsequent transmit status. If set to 0, no
transmit status frame will be sent out the serial port.
MSB 5 0x00
6 0x13
7 0xA2
64-bit
Destination
Address
8 0x00
9 0x40
10 0x40
64-bit address of the destination device (big endian byte
order). For unicast transmissions, set to the 64-bit
address of the destination device, or to
0x0000000000000000 to send a unicast to the
coordinator. Set to 0x000000000000FFFF for broadcast.
11 0x12
12 0x34
16-bit
Destination
Network
Address
MSB 13 0x56
LSB 14 0x78
Source
Endpoint
a Frame-specific Destination
c Data
Endpoint
Cluster ID
15 0x41
Set to the source endpoint on the sending device. (0x41
arbitrarily selected).
16 0x42
Set to the destination endpoint on the remote device.
(0x42 arbitrarily selected)
MSB 17 0x07
LSB 18 0x01
MSB 19 0x01
Profile ID
16-bit address of the destination device (big endian byte
order). Set to 0xFFFE for broadcast, or if the 16-bit
address is unknown.
LSB 20 0x09
Set to the cluster ID that corresponds to the ZCL
command being sent.
0x0701 = Demand response and load control cluster ID
Set to the profile ID supported on the device.
0x0109 = Smart Energy profile ID.
Broadcast
Radius
21 0x00
Sets the maximum number of hops a broadcast
transmission can traverse. If set to 0, the transmission
radius will be set to the network maximum hops value.
Transmit
Options
22 0x00
All bits must be set to 0.
23 0x09
Bitfield that defines the command type and other relevant
information in the ZCL command. See the ZCL
specification for details.
24 0x01
A sequence number used to correlate a ZCL command
with a ZCL response. (The hardware version response
will include this byte as a sequence number in the
response.) The value 0x01 was arbitrarily selected.
25 0x00
Since the frame control "frame type" bits are 01, this byte
specifies a cluster-specific command. Command ID 0x00
in the Demand Response and Load Control cluster is a
Load Control Event command. (See Smart Energy
specification.)
Data Payload
Frame Control
ZCL Frame
Header
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Transaction
Sequence
Number
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XBee®/XBee‐PRO® ZB RF Modules
Frame Fields
Offset
Example
26 0x78
27 0x56
Issuer Event ID
28 0x34
29 0x12
30 0x14
Device Class
Utility
Enrollment
Group
31 0x00
32 0x00
Description
4-byte unique identifier.
Note the 4-byte ID is sent in little endian byte order
(0x78563412).
The event ID in this example (0x12345678) was
arbitrarily selected.
to apply the load control event.
A bit value of 0x0014 enables smart appliances and
water heaters.
Note the 2-byte bit field value is sent in little endian byte
order.
Used to identify sub-groups of devices in the deviceclass. 0x00 addresses all groups.
33 0x00
Start Time
34 0x00
35 0x00
UTC timestamp representing when the event should
start. A value of 0x00000000 indicates "now".
36 0x00
ZCL Payload Load Control
Event Data
Duration in
Minutes
37 0x01
Criticality Level
39 0x04
Indicates the criticality level of the event. In this example,
the level is "voluntary".
Cooling
Temperature
40 0xFF
Requested offset to apply to the normal cooling set point.
A value of 0xFF indicates the temperature offset value is
not used.
Heating
Temperature
Offset
41 0xFF
Requested offset to apply to the normal heating set point.
A value of 0xFF indicates the temperature offset value is
not used.
38 0x00
42 0x00
Cooling
Temperature
Set Point
Heating
Temperature
Set Point
Checksum
43 0x80
44 0x00
45 0x80
This 2-byte value must be sent in little endian byte order.
Requested cooling set point in 0.01 degrees Celsius.
A value of 0x8000 means the set point field is not used in
this event.
Note the 0x80000 is sent in little endian byte order.
Requested heating set point in 0.01 degrees Celsius.
A value of 0x8000 means the set point field is not used in
this event.
Note the 0x80000 is sent in little endian byte order.
Maximum energy usage limit.
A value of 0x80 indicates the field is not used.
Average Load
Adjustment
Percentage
46 0x80
Duty Cycle
47 0xFF
Defines the maximum "On" duty cycle.
A value of 0xFF indicates the duty cycle is not used in this
event.
Duty Cycle
Event Control
48 0x00
A bitmap describing event options.
49 0x5B
0xFF minus the 8 bit sum of bytes from offset 3 to this
byte.
In the above example, the Frame Control field (offset 23) was constructed as follows:
Name
Bits Example Value Description
Frame Type
0-1
01 - Command is specific to a cluster
Manufacturer Specific
0 - The manufacturer code field is omitted from the ZCL Frame Header.
Direction
1 - The command is being sent from the server side to the client side.
Disable Default Response
0 - Default response not disabled
Reserved
5-7
Set to 0.
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10. XBee Command Reference Tables
Addressing
Addressing Commands
AT
Name and Description
Command
Parameter Range
Default
DH
Destination Address High.Set/Get the upper 32 bits of the 64-bit destination address.
When combined with DL, it defines the 64-bit destination address for data transmission.
0 - 0xFFFFFFFF
Special definitions for DH and DL include 0x000000000000FFFF (broadcast) and
0x0000000000000000 (coordinator).
DL
Destination Address Low. Set/Get the lower 32 bits of the 64-bit destination address.
When combined with DH, it defines the 64-bit destination address for data
0 - 0xFFFFFFFF
transmissions. Special definitions for DH and DL include 0x000000000000FFFF
(broadcast) and 0x0000000000000000 (coordinator).
0xFFFF(Coordinator)
0 (Router/End Device)
MY
16-bit Network Address. Read the 16-bit network address of the module. A value of
0xFFFE means the module has not joined a ZigBee network
0 - 0xFFFE
[read-only]
0xFFFE
MP
16-bit Parent Network Address. Read the 16-bit network address of the module's
parent. A value of 0xFFFE means the module does not have a parent.
0 - 0xFFFE
[read-only]
0xFFFE
NC
Number of Remaining Children. Read the number of end device children that can join 0 - MAX_CHILDREN
the device. If NC returns 0, then the device cannot allow any more end device children
(maximum varies)
to join.
SH
Serial Number High. Read the high 32 bits of the module's unique 64-bit address.
0 - 0xFFFFFFFF 
[read-only]
factory-set
SL
Serial Number Low. Read the low 32 bits of the module's unique 64-bit address.
0 - 0xFFFFFFFF
[read-only]
factory-set
NI
Node Identifier. Stores a string identifier. The register only accepts printable ASCII
data. In AT Command Mode, a string can not start with a space. A carriage return ends
the command. Command will automatically end when maximum bytes for the string
20-Byte printable 
have been entered. This string is returned as part of the ND (Node Discover) command. ASCII string
This identifier is also used with the DN (Destination Node) command. In AT command
mode, an ASCII comma (0x2C) cannot be used in the NI string
ASCII space
character (0x20)
SE
Source Endpoint. Set/read the ZigBee application layer source endpoint value. This
value will be used as the source endpoint for all data transmissions. SE is only used in 0 - 0xFF
transparent mode.The default value 0xE8 (Data endpoint) is the Digi data endpoint
0xE8
DE
Destination Endpoint. Set/read Zigbee application layer destination ID value. This
value will be used as the destination endpoint all data transmissions. DE is only used in 0 - 0xFF
transparent mode.The default value (0xE8) is the Digi data endpoint.
0xE8
CI
Cluster Identifier. Set/read Zigbee application layer cluster ID value. This value will be
used as the cluster ID for all data transmissions. CI is only used in transparent
0 - 0xFFFF
mode.The default value0x11 (Transparent data cluster ID).
0x11
NP
Maximum RF Payload Bytes. This value returns the maximum number of RF payload
bytes that can be sent in a unicast transmission. If APS encryption is used (API transmit
option bit enabled), the maximum payload size is reduced by 9 bytes. If source routing
0 - 0xFFFF
is used (AR < 0xFF), the maximum payload size is reduced further.
Note: NP returns a hexadecimal value. (e.g. if NP returns 0x54, this is equivalent to 84
bytes)
[read-only]
DD
Device Type Identifier. Stores a device type value. This value can be used to
differentiate different XBee-based devices. Digi reserves the range 0 - 0xFFFFFF.
For the XBee ZB SMT module, the device type is 0xA0000.
0xA0000
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0 - 0xFFFFFFFF
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XBee®/XBee‐PRO® ZB RF Modules
Networking
Networking Commands
AT
Name and Description
Command
Parameter Range
Default
CH
XBee
0, 0x0B - 0x1A
Operating Channel. Read the channel number used for transmitting and receiving
between RF modules. Uses 802.15.4 channel numbers. A value of 0 means the device XBee-PRO
has not joined a PAN and is not operating on any channel.
0, 0x0B - 0x19
(Channels 11-25)
CE
Coordinator Enable. Set/read whether module is a coordinator.
ID
Extended PAN ID. Set/read the 64-bit extended PAN ID. If set to 0, the coordinator will
0select a random extended PAN ID, and the router / end device will join any extended
PAN ID. Changes to ID should be written to non-volatile memory using the WR
0xFFFFFFFFFFFFFFFF
command to preserve the ID setting if a power cycle occurs.
OP
Operating Extended PAN ID. Read the 64-bit extended PAN ID. The OP value reflects 0x01 the operating extended PAN ID that the module is running on. If ID > 0, OP will equal ID. 0xFFFFFFFFFFFFFFFF
[read-only]
NH
Maximum Unicast Hops. Set / read the maximum hops limit. This limit sets the
maximum broadcast hops value (BH) and determines the unicast timeout. The timeout
0 - 0xFF
is computed as (50 * NH) + 100 ms. The default unicast timeout of 1.6 seconds
(NH=0x1E) is enough time for data and the acknowledgment to traverse about 8 hops.
0x1E
BH
Broadcast Hops. Set/Read the maximum number of hops for each broadcast data
transmission. Setting this to 0 will use the maximum number of hops.
OI
Operating 16-bit PAN ID. Read the 16-bit PAN ID. The OI value reflects the actual 160 - 0xFFFF
bit PAN ID the module is running on.
[read-only]
NT
Node Discovery Timeout. Set/Read the node discovery timeout. When the network
discovery (ND) command is issued, the NT value is included in the transmission to
provide all remote devices with a response timeout. Remote devices wait a random
time, less than NT, before sending their response.
0x20 - 0xFF [x 100 msec]
0x3C (60d)
0 - 0x03 [bitfield]
XBee
1 - 0xFFFF [bitfield]
XBee-PRO
1-0x7FFF
(bit 15 is not allowed)
7FFF
NO
Network Discovery options. Set/Read the options value for the network discovery
command. The options bitfield value can change the behavior of the ND (network
discovery) command and/or change what optional values are returned in any received
ND responses or API node identification frames. Options include:
0x01 = Append DD value (to ND responses or API node identification frames)
002 = Local device sends ND response frame when ND is issued.
[read-only]
0 - Not a coordinator
1 - Coordinator
(SM must be 0 in order to
set CE to 1.)
0 - 0x1E
SC
Scan Channels. Set/Read the list of channels to scan.
Coordinator - Bit field list of channels to choose from prior to starting network.
Router/End Device - Bit field list of channels that will be scanned to find a Coordinator/
Router to join.
Changes to SC should be written using WR command to preserve the SC setting if a
power cycle occurs.
Bit (Channel):
0 (0x0B)
4 (0x0F)
8 (0x13)
12 (0x17)
1 (0x0C)
5 (0x10)
9 (0x14)
13 (0x18)
2 (0x0D)
6 (0x11)
10 (0x15)
14 (0x19)
3 (0x0E)
7 (0x12)
11 (0x16)
15 (0x1A)
SD
Scan Duration. Set/Read the scan duration exponent. Changes to SD should be
written using WR command.
Note: If channel 26 (0x8000) is enabled in the search channel mask (SC), transmit
power on all channels will be capped at 3 dBm during network formation or joining.
Coordinator - Duration of the Active and Energy Scans (on each channel) that are
used to determine an acceptable channel and Pan ID for the Coordinator to startup on.
Router / End Device - Duration of Active Scan (on each channel) used to locate an
available Coordinator / Router to join during Association.
Scan Time is measured as:(# Channels to Scan) * (2 ^ SD) * 15.36ms - The number of
channels to scan is determined by the SC parameter. The XBee can scan up to 16
0 - 7 [exponent]
channels (SC = 0xFFFF).
Sample Scan Duration times (13 channel scan):
If SD = 0, time = 0.200 sec

SD = 2, time = 0.799 sec

SD = 4, time = 3.190 sec

SD = 6, time = 12.780 sec
Note: SD influences the time the MAC listens for beacons or runs an energy scan on a
given channel. The SD time is not a good estimate of the router/end device joining time
requirements. ZigBee joining adds additional overhead including beacon processing on
each channel, sending a join request, etc. that extend the actual joining time.
ZS
ZigBee Stack Profile. Set / read the ZigBee stack profile value. This must be set the
same on all devices that should join the same network.
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XBee®/XBee‐PRO® ZB RF Modules
Networking Commands
AT
Name and Description
Command
Parameter Range
Default
0 - 0xFF 
[x 1 sec]
0xFF 
(always allows joining)
NJ
Node Join Time. Set/Read the time that a Coordinator/Router allows nodes to join.
This value can be changed at run time without requiring a Coordinator or Router to
restart. The time starts once the Coordinator or Router has started. The timer is reset
on power-cycle or when NJ changes.
For an end device to enable rejoining, NJ should be set less than 0xFF on the device
that will join. If NJ < 0xFF, the device assumes the network is not allowing joining and
first tries to join a network using rejoining. If multiple rejoining attempts fail, or if
NJ=0xFF, the device will attempt to join using association.
JV
Channel Verification. Set/Read the channel verification parameter. If JV=1, a router or
end device will verify the coordinator is on its operating channel when joining or coming
up from a power cycle. If a coordinator is not detected, the router or end device will
leave its current channel and attempt to join a new PAN. If JV=0, the router or end
device will continue operating on its current channel even if a coordinator is not
detected.
NW
Network Watchdog Timeout. Set/read the network watchdog timeout value. If NW is
0 - 0x64FF
set > 0, the router will monitor communication from the coordinator (or data collector)
and leave the network if it cannot communicate with the coordinator for 3 NW periods. [x 1 minute]
The timer is reset each time data is received from or sent to a coordinator, or if a many- (up to over 17 days)
to-one broadcast is received.
0 (disabled)
JN
Join Notification. Set / read the join notification setting. If enabled, the module will
transmit a broadcast node identification packet on power up and when joining. This
action blinks the Associate LED rapidly on all devices that receive the transmission, and 0 - 1
sends an API frame out the serial port of API devices. This feature should be disabled
for large networks to prevent excessive broadcasts.
AR
Aggregate Routing Notification. Set/read time between consecutive aggregate route
broadcast messages. If used, AR should be set on only one device to enable many-to- 0 - 0xFF
one routing to the device. Setting AR to 0 only sends one broadcast
0xFF
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0 - Channel verification
disabled
1 - Channel verification
enabled
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XBee®/XBee‐PRO® ZB RF Modules
Security
Security Commands
AT
Name and Description
Command
Parameter Range
Default
EE
Encryption Enable. Set/Read the encryption enable setting.
0 - Encryption disabled
1 - Encryption enabled
EO
Encryption Options. Configure options for encryption. Unused option bits should be set
to 0. Options include:
0 - 0xFF
0x01 - Send the security key unsecured over-the-air during joins
0x02 - Use trust center (coordinator only
NK
Network Encryption Key. Set the 128-bit AES network encryption key. This command
is write-only; NK cannot be read. If set to 0 (default), the module will select a random
network key.
128-bit value
KY
Link Key. Set the 128-bit AES link key. This command is write only; KY cannot be read.
Setting KY to 0 will cause the coordinator to transmit the network key in the clear to
128-bit value
joining devices, and will cause joining devices to acquire the network key in the clear
when joining.
RF Interfacing
RF Interfacing Commands
AT
Name and Description
Command
Parameter Range
Default
PL
XBee
(boost mode disabled)
0 = -5 dBm
1 = -1 dBm
Power Level. Select/Read the power level at which the RF module transmits conducted 2 = +1 dBm
power. For XBee-PRO (S2B) Power Level 4 is calibrated and the other power levels are 3 = +3 dBm
4 = +5 dBm
approximate. Calibration occurs every 15 seconds based on radio characteristics
determined at manufacturing time, the ambient temperature, and how far off the voltage
is from the typical 3.3 V. If the input voltage is too high, the module will reset.
XBee-PRO
For the regular XBee, when operating on channel 26, no PL/PM selection will allow
(Boost mode enabled)
greater than +3 dBm output.
4 =+18 dBM
3 = +16 dBm (approx.)
2 = +14 dBm (approx.)
1 = +12 dBm (approx.)
0 = 0 dBm (approx.)
PM
Power Mode (XBee only). Set/read the power mode of the device. Enabling boost mode
0-1, 
will improve the receive sensitivity by 2dB and increase the transmit power by 3dB
0= -Boost mode disabled,
Note:This command is disabled on the XBee-PRO. It is forced on by the software to
1= Boost mode enabled. 1
provide the extra sensitivity. Boost mode imposes a slight increase in current draw. See
section 1.2 for details.
DB
Received Signal Strength. This command reports the received signal strength of the
last received RF data packet or APS acknowledgment. The DB command only indicates
the signal strength of the last hop. It does not provide an accurate quality measurement
for a multihop link. DB can be set to 0 to clear it. The DB command value is measured in
-dBm. For example if DB returns 0x50, then the RSSI of the last packet received was
-80dBm.
0 - 0xFF
Observed range for
XBee-PRO:
0x1A - 0x58
For XBee:
0x 1A - 0x5C
PP
Peak Power. Read the dBm output when maximum power is selected (PL4).
0x0-0x12
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XBee®/XBee‐PRO® ZB RF Modules
Serial Interfacing (I/O)
Serial Interfacing Commands
AT
Name and Description
Command
AP
AO
API Enable. Enable API Mode. This command is ignored when using SPI. API mode 1 is
always used.
API Options. Configure options for API. Current options select the type of receive API
frame to send out the Uart for received RF data packets.
Parameter Range
Default
0 = API-disabled
(operate in 
transparent mode)
1 = API-enabled
2 = API-enabled 
(w/escaped control
characters)
0 - Default receive API
indicators enabled
1 - Explicit Rx data
indicator API frame
enabled (0x91)
3 - enable ZDO
passthrough of ZDO
requests to the serial port
which are not supported
by the stack, as well as
Simple_Desc_req,
Active_EP_req, and
Match_Desc_req.
BD
0 - 0x0A
(standard baud rates)
0 = 1200 bps
1 = 2400
Interface Data Rate. Set/Read the serial interface data rate for communication between
2 = 4800
the module serial port and host.
3 = 9600
Any value above 0x0A will be interpreted as an actual baud rate.
4 = 19200
Standard baud rates are supported.
5 = 38400
Non-standard baud rates are permitted but their performance is not guaranteed.
6 = 57600
7 = 115200
8 = 230400
9 = 460800
A = 921600
NB
Serial Parity. Set/Read the serial parity setting on the UART.
0 = No parity
1 = Even parity
2 = Odd parity
3 = Mark parity
SB
Stop Bits. Set/read the number of stop bits for the UART. (Two stop bits are not
supported if mark parity is enabled.)
0 = 1 stop bit
1 = 2 stop bits
RO
Packetization Timeout. Set/Read number of character times of inter-character silence
required before packetization. Set (RO=0) to transmit characters as they arrive instead of 0 - 0xFF
buffering them into one RF packet The RO command is only supported when operating [x character times]
in transparent mode.
D7
D6
DIO7 Configuration. Select/Read options for the DIO7 line of the RF module.
0 = Unmonitored digital
input
1 = CTS Flow Control
3 = Digital input
4 = Digital output, low
5 = Digital output, high
6 = RS-485 transmit
enable (low enable)
7 = RS-485 transmit
enable (high enable)
DIO6 Configuration. Configure options for the DIO6 line of the RF module.
0 = Unmonitored digital
input
1 = RTS flow control
3 = Digital input
4 = Digital output, low
5 = Digital output, high
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XBee®/XBee‐PRO® ZB RF Modules
I/O Commands
I/O Commands
AT
Name and Description
Command
Parameter Range
Default
0, 0x32:0xFFFF (ms)
IR
I/O Sample Rate. Set/Read the I/O sample rate to enable periodic sampling. For
periodic sampling to be enabled, IR must be set to a non-zero value, and at least one
module pin must have analog or digital I/O functionality enabled (see D0-D9, P0-P4
commands). The sample rate is measured in milliseconds.
IC
I/O Digital Change Detection. Set/Read the digital I/O pins to monitor for changes in
the I/O state. IC works with the individual pin configuration commands (D0-D9, P0-P4). If
a pin is enabled as a digital input/output, the IC command can be used to force an
immediate I/O sample transmission when the DIO state changes. IC is a bitmask that
can be used to enable or disable edge detection on individual channels. Unused bits
: 0 - 0xFFFF
should be set to 0.
Bit (IO pin): 0 (DIO0)4 (DIO4)8 (DIO8)
1 (DIO1) 5 (DIO5) 9 (DIO9)
2 (DIO2) 6 (DIO6) 10 (DIO10)
3 (DIO3) 7 (DIO7) 11 (DIO11)
PWM0 Configuration. Select/Read function for PWM0.
0 = Unmonitored digital
input
1 = RSSI PWM
3 - Digital input,
monitored
4 - Digital output, default
low
5 - Digital output, default
high
PWM1 / DIO11 Configuration. Configure options for the DIO11 line of the RF module.
0 - Unmonitored digital
input
1 - Output 50% duty
cycle clock at 32.787 kHz
3- Digital input,
monitored
4- Digital output, default
low
5- Digital output, default
high
P2
DIO12 Configuration. Configure options for the DIO12 line of the RF module.
0 - Unmonitored digital
input
1 - SPI_MISO*
3- Digital input,
monitored
4- Digital output, default
low
5- Digital output, default
high
P3
0 – Unmonitored digital
input
1 – Data out for UART
DIO13 / DOUT Configuration. Set/Read function for DIO13. Configure options for the
3 – Monitored digital
DIO13 line of the RF module.
input
4 – Digital output low
5 – Digital output high
P4
DIO14 / DIN. Set/read function for DIO14.
0 – Unmonitored digital
input
1 – Data in for UART
3 – Digital input
4 – Digital output low
5 – Digital output high
P5**
DIO15 / SPI_MISO. Set/read function for DIO15.
0 – Unmonitored digital
input
1 – Output from SPI port
P6**
DIO16 / SPI_MOSI. Set/read function for DIO16.
0 – Unmonitored digital
input
1 – Input to SPI port
P7**
DIO17 / SPI_SSEL. Set/read function for DIO17.
0 – Unmonitored digital
input
1 – Input to to select the
SPI port
P0
P1
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XBee®/XBee‐PRO® ZB RF Modules
I/O Commands
AT
Name and Description
Command
Parameter Range
Default
P8**
DIO18 / SPI_SClk. Set/read function for DIO18.
0 – Unmonitored digital
input
1 – SPI clock input
DIO19 / SPI_Attn / PTI_DATA. Set/read function for DIO19.
0 – Unmonitored digital
input
1 - SPI data available
indicator
6 – Packet trace interface
data output. Must be set
along with D1=6 to output
traces for OTA sniffing.
AD0/DIO0 Configuration. Select/Read function for AD0/DIO0.
0 - Unmonitored digital
input
1 - Commissioning button
enabled
2 - Analog input, single
ended
3 - Digital input
4 - Digital output, low
5 - Digital output, high
P9**
D0
D1
AD1/DIO1 / PTI_En Configuration. Select/Read function for AD1/DIO1.
0 – Unmonitored digital
input
1 – SPI_nATTN*
2 – Analog input, single
ended
3 – Digital input
4 – Digital output, low
5 – Digital output, high
6 - Packet trace interface
enable. Must be set
along with P9=6 to output
traces for OTA sniffing.
AD2/DIO2 Configuration. Select/Read function for AD2/DIO2.
0 – Unmonitored digital
input
1 – SPI_SCLK*
2 – Analog input, single
ended
3 – Digital input
4 – Digital output, low
5 – Digital output, high
AD3/DIO3 Configuration. Select/Read function for AD3/DIO3.
0 – Unmonitored digital
input
1 – SPI_nSSEL*
2 – Analog input, single
ended
3 – Digital input
4 – Digital output, low
5 – Digital output, high
D4
DIO4 Configuration. Select/Read function for DIO4.
0 – Unmonitored digital
input
1 – SPI_MOSI*
3 – Digital input
4 – Digital output, low
5 – Digital output, high
D5
0 - Unmonitored digital
input
1 - Associated indication
LED
DIO5 / Associate Configuration. Configure options for the DIO5 line of the RF module. 3 - Digital input
4 - Digital output, default
low
5 - Digital output, default
high
D2
D3
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I/O Commands
AT
Name and Description
Command
Parameter Range
D8
DIO8 / DTR / Slp_Rq. Set/Read function for DIO8.
0 – Unmonitored digital
input
1 – Input to sleep and
wake module
3 – Digital input
4 – Digital output, low
5 – Digital output, high
LT
Assoc LED Blink Time. Set/Read the Associate LED blink time. If the Associate LED
functionality is enabled (D5 command), this value determines the on and off blink times
0, 0x0A - 0xFF (100 for the LED when the module has joined a network. If LT=0, the default blink rate will be
2550 ms)
used (500ms coordinator, 250ms router/end device). For all other LT values, LT is
measured in 10ms.
PR
Pull-up/down Resistor. Set/read the bit field that configures the internal pull-up/down
resistor status for the I/O lines. "1" specifies the pull-up/down resistor is enabled. "0"
specifies no internal resistors are used. The input will be floating.
Bits:"
0 - DIO4 (Pin 24)
1 - AD3 / DIO3 (Pin 30)
2 - AD2 / DIO2 (Pin 31)
3 - AD1 / DIO1 (Pin 32)
4 - AD0 / DIO0 (Pin 33)
5 - RTS / DIO6 (Pin 29)
6 - DTR / Sleep Request / DIO8 (Pin 10)
7 - DIN / Config (Pin 4)
8 - Associate / DIO5 (Pin 28)
9 - On/Sleep / DIO9 (Pin 26)
10 - DIO12 (Pin 5)
11 - PWM0 / RSSI / DIO10 (Pin 7)
12 - PWM1 / DIO11 (Pin 8)
13 - CTS / DIO7 (Pin 25)
14 - DOUT / DIO13 (Pin 3)
0 - 0x7FFF
0x1FFF
PD
Pull-up / down direction. Set/read an internal pull-up or pull-down resistor for the
corresponding bits in the PR command. If the bit is set, an internal pull-up resistor is
0 - 0x7FFF
used. If it is clear, an internal pull-down resistor is used. See the PR command for the bit
order.
0x1FBF
RP
RSSI PWM Timer. Time the RSSI signal will be output on the PWM after the last RF data
0 - 0xFF [x 100 ms]
reception or APS acknowledgment.. When RP = 0xFF, output will always be on.
0x28 (40d)
DO
Device Options.
Bit0 - Reserved.
Bit1 - Reserved for Smart Energy devices.
Bit2 - 0/1 = First or Best Join. First join means the device will join the network
through the first acceptable Beacon response it receives. Best join means the device will
join the network through the strongest Beacon response it receives after searching all
search mask channels.
0x00-0xFF
Bit3 - Disable NULL Transport Key (Coordinator Only).
Bit4 - Disable Tx Packet Extended Timeout.
Bit5 - Disable ACK for End Device I/O Sampling.
Bit6 - Enable High Ram Concentrator.
Bit7 - Enable ATNW to find new network before leaving the network.
Bit8 - Verbose Join. See XBee ZigBee API Operation frame type 0x98, Extended
Modem Status, for a full description.
0x00
%V
Supply Voltage. Reads the voltage on the Vcc pin in mV.
V+
Voltage Supply Monitoring. The voltage supply threshold is set with the V+ command.
If the measured supply voltage falls below or equal to this threshold, the supply voltage
will be included in the IO sample set. V+ is set to 0 by default (do not include the supply 0-0xFFFF
voltage).The units of this command are mV. For example, to include a measurement of
the supply voltage when it exceeds 3.3 V, set V+ to 3300 = 0xCE4.
TP
Reads the module temperature in Degrees Celsius. Accuracy +/- 7 degrees.
1° C = 0x0001 and -1° C = 0xFFFF. Command is only available on PRO module.
-0x-0xFFFF [read only]
0x0-0xFFFF
Default
• * indicates that the option is available on the TH module, but not the SMT module.
• ** indicates that the command is available on the SMT module, but not the TH module.
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Diagnostics
Diagnostics Commands
AT
Name and Description
Command
Parameter Range
Default
VR
Firmware Version. Read firmware version of the module as a 4-digit hex number.
0 - 0xFFFF [read-only]
Factory-set
VL
Version Long. Shows detailed version information, module type, a time stamp for the
build, Ember stack version, and bootloader version.
N/A
N/A
HV
Hardware Version. Read the hardware version of the module.version of the module.
This command can be used to distinguish among different hardware platforms. The
upper byte returns a value that is unique to each module type. The lower byte indicates
0 - 0xFFFF [read-only]
the hardware revision.
The regular XBee returns a value of 0x22xx for this command. the XBee-PRO returns a
value of 0x21xx.
Factory-set
AI
Association Indication. Read information regarding last node join request:
0x00 - Successfully formed or joined a network. (Coordinators form a network, routers
and end devices join a network.)
0x21 - Scan found no PANs
0x22 - Scan found no valid PANs based on current SC and ID settings
0x23 - Valid Coordinator or Routers found, but they are not allowing joining (NJ expired)
0x24 - No joinable beacons were found
0x25 - Unexpected state, node should not be attempting to join at this time
0x27 - Node Joining attempt failed (typically due to incompatible security settings)
0x2A - Coordinator Start attempt failed‘
0 - 0xFF
0x2B - Checking for an existing coordinator
[read-only]
0x2C - Attempt to leave the network failed
0xAB - Attempted to join a device that did not respond.
0xAC - Secure join error - network security key received unsecured
0xAD - Secure join error - network security key not received
0xAF - Secure join error - joining device does not have the right preconfigured link key
0xFF - Scanning for a ZigBee network (routers and end devices)
Note: New non-zero AI values may be added in later firmware versions. Applications
should read AI until it returns 0x00, indicating a successful startup (coordinator) or join
(routers and end devices)
--
AT Command Options
AT Command Options Commands
AT
Name and Description
Command
Parameter Range
Default
CT
Command Mode Timeout. Set/Read the period of inactivity (no valid commands
received) after which the RF module automatically exits AT Command Mode and returns 2 - 0x028F [x 100 ms]
to Idle Mode.
0x64 (100d)
CN
Exit Command Mode. Explicitly exit the module from AT Command Mode.
--
GT
Guard Times. Set required period of silence before and after the Command Sequence
1 - 0x0CE4 [x 1 ms]
0x3E8
Characters of the AT Command Mode Sequence (GT + CC + GT). The period of silence
(max of 3.3 decimal sec) (1000d)
is used to prevent inadvertent entrance into AT Command Mode.
CC
Command Sequence Character. Set/Read the ASCII character value to be used
between Guard Times of the AT Command Mode Sequence (GT + CC + GT). The AT
Command Mode Sequence enters the RF module into AT Command Mode.
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--
0 - 0xFF
0x2B 
(‘+’ ASCII)
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XBee®/XBee‐PRO® ZB RF Modules
Sleep Commands
Sleep Commands
AT
Name and Description
Command
Parameter Range
Default
SM
Sleep Mode Sets the sleep mode on the RF module. When SM>0, the module operates
as an end device. However, CE must be 0 before SM can be set to a value greater than
0 to turn the module into an end device. Changing a device from a router to an end
device (or vice versa) forces the device to leave the network and attempt to join as the
new device type when changes are applied.
SN
Number of Sleep Periods. Sets the number of sleep periods to not assert the On/Sleep
pin on wakeup if no RF data is waiting for the end device. This command allows a host 1 - 0xFFFF
application to sleep for an extended time if no RF data is present
SP
Sleep Period. This value determines how long the end device will sleep at a time, up to
28 seconds. (The sleep time can effectively be extended past 28 seconds using the SN 0x20 - 0xAF0 x 10ms
command.) On the parent, this value determines how long the parent will buffer a
(Quarter second
message for the sleeping end device. It should be set at least equal to the longest SP
resolution)
time of any child end device.
0x20
ST
Time Before Sleep Sets the time before sleep timer on an end device.The timer is reset
each time serial or RF data is received. Once the timer expires, an end device may enter 1 - 0xFFFE (x 1ms)
low power operation. Applicable for cyclic sleep end devices only.
0x1388 (5
seconds)
SO
Command
Sleep Options. Configure options for sleep. Unused option bits should be set to 0.
Sleep options include:
0x02 - Always wake for ST time
0x04 - Sleep entire SN * SP time
Sleep options should not be used for most applications. See chapter 6 for more
information.
WH
Wake Host. Set/Read the wake host timer value. If the wake host timer is set to a nonzero value, this timer specifies a time (in millisecond units) that the device should allow
0 - 0xFFFF (x 1ms)
after waking from sleep before sending data out the serial port or transmitting an I/O
sample. If serial characters are received, the WH timer is stopped immediately.
SI
Sleep Immediately. See Execution Commands table below..
PO
Polling Rate. Set/Read the end device poll rate. Setting this to 0 (default) enables
polling at 100 ms (default rate), advancing in 10 msec increments. Adaptive polling may 0 - 0x3E8
allow the end device to poll more rapidly for a short time when receiving RF data.
0-Sleep disabled (router)
0 - Router
1-Pin sleep enabled
4 - End
4-Cyclic sleep enabled
Device
5 - Cyclic sleep, pin wake
0 - 0xFF
0x00 (100
msec)
Execution Commands
Where most AT commands set or query register values, execution commands cause an action to
be executed on the module. Execution commands are executed immediately and do not require
changes to be applied.
AT
Name and Description
Command
Parameter Range Default
AC
Apply Changes. Applies changes to all command registers causing queued command
register values to be applied. For example, changing the serial interface rate with the BD
command will not change the UART interface rate until changes are applied with the AC
command. The CN command and 0x08 API command frame also apply changes.
AS
Active Scan. Scans the neighborhood for beacon responses. Response frames are
structured as:
AS_type – unsigned byte = 2 - ZB firmware uses a different format than WiFi XBee,
which is type 1
Channel – unsigned byte
PAN – unsigned word in big endian format
Extended PAN – eight unsigned bytes in bit endian format
Allow Join – unsigned byte – 1 indicates join is enabled, 0 that it is disabled
Stack Profile – unsigned byte
LQI – unsigned byte, higher values are better
RSSI – signed byte, lower values are better
WR
Write. Write parameter values to non-volatile memory so that parameter modifications
persist through subsequent resets.
-Note: Once WR is issued, no additional characters should be sent to the module until
after the "OK\r" response is received. The WR command should be used sparingly. The
EM357 supports a limited number of write cycles.
--
RE
Restore Defaults. Restore module parameters to factory defaults.
--
--
FR
Software Reset. Reset module. Responds immediately with an OK status, and then
performs a software reset about 2 seconds later.
--
--
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AT
Name and Description
Command
Parameter Range Default
NR
Network Reset. Reset network layer parameters on one or more modules within a PAN.
Responds immediately with an “OK” then causes a network restart. All network
configuration and routing information is consequently lost.
0-1
If NR = 0: Resets network layer parameters on the node issuing the command.
If NR = 1: Sends broadcast transmission to reset network layer parameters on all nodes
in the PAN.
--
SI
Sleep Immediately. Cause a cyclic sleep module to sleep immediately rather than wait
for the ST timer to expire.
CB
Commissioning Pushbutton. This command can be used to simulate commissioning
button presses in software. The parameter value should be set to the number of button
presses to be simulated. For example, sending the ATCB1 command will execute the
action associated with 1 commissioning button press.
&X
Clear Binding and Group Tables. This command resets the binding and group tables.
ND
Node Discover. Discovers and reports all RF modules found. The following information
is reported for each module discovered.
MY
SH
SL
NI (Variable length)
PARENT_NETWORK ADDRESS (2 Bytes)
DEVICE_TYPE (1 Byte: 0=Coord, 1=Router, 2=End Device)
STATUS (1 Byte: Reserved)
PROFILE_ID (2 Bytes)
MANUFACTURER_ID (2 Bytes)
optional 20-Byte 

After (NT * 100) milliseconds, the command ends by returning a . ND also accepts NI or MY value
a Node Identifier (NI) as a parameter (optional). In this case, the first module with a
matching NI identifier to respond will be returned. If no module matches, then "ERROR"
will be returned.
If ND is sent through the API, each response is returned as a separate
AT_CMD_Response packet. The data consists of the above listed bytes without the
carriage return delimiters. The NI string will end in a "0x00" null character. The radius of
the ND command is set by the BH command.
--
Refer to the description of the NO command for options which affect the behavior of the
ND command.
DN
Destination Node. Resolves an NI (Node Identifier) string to a physical address (casesensitive). The following events occur after the destination node is discovered:

1. DL & DH are set to the extended (64-bit) address of the module with the matching 
NI (Node Identifier) string.
2. OK (or ERROR)\r is returned. 
3. Command Mode is exited to allow immediate communication
up to 20-Byte printable
-ASCII string

1. The 16-bit network and 64-bit extended addresses are returned in an API 
Command Response frame.
If there is no response from a module within (NT * 100) milliseconds or a parameter is
not specified (left blank), the command is terminated and an “ERROR” message is
returned. In the case of an ERROR, Command Mode is not exited. The radius of the DN
command is set by the BH command.
IS
Force Sample Forces a read of all enabled digital and analog input lines.
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--
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11. XBee ZigBee Module Support
This chapter provides customization information for the XBee. In addition to providing an extremely flexible and powerful
API, XBee modules are a robust development platform that have passed FCC and ETSI testing. Developers can customize
default parameters, or even write or load custom firmware for Ember's EM357 chip.
X-CTU Configuration Tool
Digi provides a Windows X-CTU configuration tool for configuring module parameters and updating firmware. The
XCTU has the capability to do the following:
•Discover all XBee devices in the network
•Update firmware on a local module (requires USB or serial connection)
•Read or write module configuration parameters on a local or remote device
•Save and load configuration profiles containing customized settings.
Contact Digi support for more information about the X-CTU.
Customizing XBee ZB Firmware
Once module parameters are tested in an application and finalized, Digi can manufacture modules with specific,
customer-defined configurations for a nominal fee. These custom configurations can lock in a firmware version or set
command values when the modules are manufactured, eliminating the need for customers to adjust module
parameters on arrival. Alternatively, Digi can program custom firmware, including Ember's EZSP UART image, into
the modules during manufacturing. Contact Digi to create a custom configuration.
Design Considerations for Digi Drop-In Networking
XBee RF modules contain a variety of features that allow for interoperability with Digi's full line of Drop-in
Networking products. Interoperability with other "DIN" products can offer these advantages:
•Add IP-connectivity to your network via Cellular, Ethernet or WiFi with a ConnectPort X Gateway.
•Extend the range of your network with the XBee Wall Router.
•Make deployment easy by enabling the Commissioning Pushbutton (pin 20) and AssociateLED (pin 15) to operate with the Network Commissioning Tool software.
•Interface with standard RS-232, USB, Analog & Digital I/O, RS-485, and other industrial devices using XBee
Adapters.
•Monitor and manage your network securely from remote locations with Device Cloud by Etherios™.
•We encourage you to contact our technical representatives for consideration, implementation, or design review
of your product for interoperability with Digi's Drop-in Networking solutions.
XBee Bootloader
XBee modules use a modified version of Ember’s bootloader. This bootloader version supports a custom entry
mechanism that uses module pins DIN (pin 4), DTR / SLEEP_RQ (pin 10), and RTS (pin 29). To invoke the bootloader,
do the following:
1. Set DTR / SLEEP_RQ low (TTL 0V) and RTS high.
2. Send a serial break to the DIN pin and power cycle or reset the module.
3. When the module powers up, DTR / SLEEP_RQ and DIN should be low (TTL 0V) and RTS should be high.
4. Terminate the serial break and send a carriage return at 115200bps to the module.
5. If successful, the module will send the Ember bootloader menu out the DOUT pin at 115200bps.
6. Commands can be sent to the bootloader at 115200bps.
Note: Hardware flow control should be disabled when entering and communicating with the Ember 357 bootloader.
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Programming XBee Modules
Firmware on the XBee modules can be updated serially.
Serial Firmware Updates
Serial firmware updates make use of the XBee custom bootloader which ships in all units. This modified
bootloader is based on Ember's standalone bootloader, but with a modified entry mechanism. The modified
entry mechanism uses module pins 4, 10, and 29 (DIN, DTR, and RTS respectively).
The X-CTU program can update firmware serially on the XBee. Contact Digi support for details.
If an application requires custom firmware to update the XBee firmware serially, the following steps are
required.
Invoke XBee Bootloader
See the "XBee Bootloader" section above for steps to invoke the bootloader using RS-232 signals. The
bootloader may also be invoked by issuing a command via X-CTU. Then the application makes an explicit call to
the bootloader, which does not return.
If there is no valid application, the bootloader will always run.
Send Firmware Image
After invoking the bootloader, the Ember bootloader will send the bootloader menu characters out the serial
port, which may be the UART at 115200 bps or the SPI, where the attached SPI master provides the clock rate.
The application should do the following to upload a firmware image.
1. Look for the bootloader prompt "BL >" to ensure the bootloader is active
2. Send an ASCII "1" character to initiate a firmware update
3. After sending a "1", the EM357 waits for an XModem CRC upload of an .ebl image over the serial line at
115200 bps. The .ebl file must be sent to the EM357 in order.
If the firmware image is successfully loaded, the bootloader will output a “complete” string. Then the newly
loaded firmware can be invoked by sending a ‘2’ to the module.
If the firmware image is not successfully loaded, the bootloader will output an “aborted” string. Then it will
return to the main bootloader menu. Some causes for failure are:
• Over 1 minute passes after the command to send the firmware image and the first block of the image has
not yet been sent.
• A power cycle or reset event occurs during the firmware load.
• A file error or a flash error occurs during the firmware load.
Writing Custom Firmware
The XBee module can be used as a hardware development platform for the EM357. Custom firmware images can be
developed around the EmberZNet 4.2.xx mesh stacks (for the EM357) and uploaded to the XBee.
Warning: If programming firmware through the JTAG interface, please be aware that doing so can potentially
erase the XBee bootloader. If this occurs, serial firmware updates will not work.
Regulatory Compliance
XBee modules are FCC and ETSI certified for operation on all 16 channels. The EM357 output power can be
configured up to 8 dBm with boost mode enabled.
XBee-PRO modules are certified for operation on 15 of the 16 band channels (channels 11 - 25). The scan
channels mask of XBee-PRO devices must be set in the application to disable the upper channel (e.g.
0x03FFF800). The XBee-PRO contains a power compensation method to adjust the output power near 18 dBm.
For best results, the EM357 should be configured with an output power level of -4 dBm with Boost mode is
enabled. The end product is responsible to adhere to these requirements.
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Enabling GPIO 1 and 2
Most of the remaining sections in this chapter describe how to configure GPIOs to function correctly in custom
applications that run on the XBee modules. In order for GPIO pins to be configurable, the application must set
the GPIO_PxCFG registers to enable the appropriate GPIO. The following table lists values for configuring the
GPIO pins. Other functionality is affected by these settings. See the EM357 datasheet from Ember for a
complete listing of functionality.
GPIO Mode
GPIO_PxCFGH/L Description
Analog
0x0
Analog input or output. When in analog mode, the digital input
(GPIO_PxIN) always reads 1.
Input (floating)
0x4
Digital input without an internal pull-up or pull-down. Output is disabled.
Input (pull-up or
pull-down)
0x8
Digital input with an internal pull-up or pull-down. A set bit in
GPIO_PxOUT selects pull-up and a cleared bit selects pull-down.
Output is disabled
Output (pushpull)
0x1
Push-pull output. GPIO_PxOUT controls the output.
Output (opendrain)
0x5
Open-drain output. GPIO_PxOUT controls the output. If a pull-up is
required, it must be external.
Alternate Output
(push-pull)
0x9
Push-pull output. An on-board peripheral controls the output.
Alternate Output
(open-drain)
0xD
Open-drain output. An on-board peripheral controls the output. If a pullup is required, it must be external.
For more information on configuring and setting GPIOs, consult the EM357 specification.
Detecting XBee vs. XBee-PRO
For some applications, it may be necessary to determine if the code is running on an XBee or an XBee-PRO
device. The PC7 pin on the EM357 is used to identify the module type (see Chapter 1). PC7 is connected to
ground on the XBee module. The following code could be used to determine if a module is an XBee or XBeePRO:
GPIO_PCSET = 0x80; // Enable pullup resistor
GPIO_PCCFGH &= 0x0fff; // Clear PC7 config
GPIO_PCCFGH |= 0x8000;// Set PC7 as input with pullup/pulldown
if (GPIO_PCIN & 0x80) {
ModuleIsXBeePro = true;
} else {
ModuleIsXBeePro = false;
Special Instructions For Using the JTAG Interface
There are four JTAG programming pins on the XBee through which firmware can be loaded onto the EM357
processor. Three of these pins are also connected to a second pin on the XBee and are used for separate
functions. The following table indicates the JTAG signal name, the primary connection pin on the XBee, the
secondary connection pin, and the secondary signal name.
It is important that the secondary pins specifically are not loaded with circuitry that might interfere with JTAG
programming (for example, an LED tied directly to the ASSOCIATE / DIO5 line). Any loading circuitry should be
buffered to avoid conflicts (for example, connecting ASSOCIATE / DIO5 to the gate of a MOSFET which drives
the LED).
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XBee®/XBee‐PRO® ZB RF Modules
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JTAG pin name
Primary XBee pin Secondary XBee pin
Secondary pin name
JTCK
18
N/A
N/A
JTDO
19
26
ON / SLEEP / DIO9
JTDI
20
28
ASSOCIATE / DIO5
JTMS
21
DIO12
155
Appendix A: Agency Certifications
United States FCC
The XBee RF Module complies with Part 15 of the FCC rules and regulations. Compliance with the labeling
requirements, FCC notices and antenna usage guidelines is required.
To fulfill FCC Certification, the OEM must comply with the following regulations:
1.The system integrator must ensure that the text on the external label provided with this
device is placed on the outside of the final product.
2.XBee RF Module may only be used with antennas that have been tested and approved for use
with this module [refer to the antenna tables in this section].
OEM Labeling Requirements
WARNING: The Original Equipment Manufacturer (OEM) must ensure that FCC labeling
requirements are met. This includes a clearly visible label on the outside of the final product
enclosure that displays the contents shown in the figure below.
Required FCC Label for OEM products containing the XBee S2C SMT RF Module
Contains FCC ID: MCQ-XBS2C
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1.) this device may not cause harmful interference and (2.) this device must accept any interference
received, including interference that may cause undesired operation.
Required FCC Label for OEM products containing the XBee-PRO S2C RF Module
Contains FCC ID:MCQ-XBPS2C
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1.) this device may not cause harmful interference and (2.) this device must accept any interference
received, including interference that may cause undesired operation.
Required FCC Label for OEM products containing the XBee S2C TH RF Module
Contains FCC ID:MCQ-S2CTH
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1.) this device may not cause harmful interference and (2.) this device must accept any interference
received, including interference that may cause undesired operation.
FCC Notices
IMPORTANT: The XBee and XBee-PRO RF Module have been certified by the FCC for use with other
products without any further certification (as per FCC section 2.1091). Modifications not expressly
approved by Digi could void the user's authority to operate the equipment.
IMPORTANT: OEMs must test final product to comply with unintentional radiators (FCC section 15.107 &
15.109) before declaring compliance of their final product to Part 15 of the FCC Rules.
IMPORTANT: The RF module has been certified for remote and base radio applications. If the module will
be used for portable applications, the device must undergo SAR testing.
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to
Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference in a residential installation. This equipment generates, uses and can radiate radio frequency
energy and, if not installed and used in accordance with the instructions, may cause harmful interference to
radio communications. However, there is no guarantee that interference will not occur in a particular
installation.
If this equipment does cause harmful interference to radio or television reception, which can be determined
by turning the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures: Re-orient or relocate the receiving antenna, Increase the separation
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XBee®/XBee‐PRO® ZB RF Modules
between the equipment and receiver, Connect equipment and receiver to outlets on different circuits, or
Consult the dealer or an experienced radio/TV technician for help.
FCC-Approved Antennas (2.4 GHz)
The XBee and XBee-PRO RF Module can be installed utilizing antennas and cables constructed with
standard connectors (Type-N, SMA, TNC, etc.).
The modules are FCC approved for fixed base station and mobile applications for the channels indicated in
the tables below. If the antenna is mounted at least 20cm (8 in.) from nearby persons, the application is
considered a mobile application. Antennas not listed in the table must be tested to comply with FCC Section
15.203 (Unique Antenna Connectors) and Section 15.247 (Emissions).
XBee RF Modules: XBee RF Modules have been tested and approved for use with all the antennas listed in
the tables below. (Cable-loss IS required when using gain antennas as shown below.)
The antennas in the tables below have been approved for use with this module. Digi does not carry all of
these antenna variants. Contact Digi Sales for available antennas.
Antennas approved for use with the XBee®/XBee‐PRO® Surface Mount RF Modules
Part Number
Type (Description)
Gain
Application*
Min Separation
Minimum Cable
Loss/Power Reduction/Attenuation
Required
Channels 11-25
Internal Antennas
29000313
Integral PCB antenna
0.0 dBi
Fixed/Mobile
20 cm
N/A
A24-QI
Monopole (Integrated whip)
1.5 dBi
Fixed/Mobile
20 cm
N/A
Dipole Antennas
A24-HASM-450
Dipole (Half-wave articulated RPSMA - 4.5”)
2.1 dBi
Fixed
20 cm
N/A
A24-HABSM
Dipole (Articulated RPSMA)
2.1 dBi
Fixed
20 cm
N/A
29000095
Dipole (Half-wave articulated RPSMA - 4.5”)
2.1 dBi
Fixed/Moblie
20 cm
N/A
A24-HABUF-P5I
Dipole (Half-wave articulated bulkhead mount U.FL. w/ 5” pigtail)
2.1 dBi
Fixed/Mobile
20 cm
N/A
A24-HASM-525
Dipole (Half-wave articulated RPSMA - 5.25")
2.1 dBi
Fixed
20 cm
N/A
N/A
Omni-directional Antennas
A24-F2NF
Omni-directional (Fiberglass base station)
2.1 dBi
Fixed/Mobile
20 cm
A24-F3NF
Omni-directional (Fiberglass base station)
3.0 dBi
Fixed/Mobile
20 cm
N/A
A24-F5NF
Omni-directional (Fiberglass base station)
5.0 dBi
Fixed
20 cm
N/A
A24-F8NF
Omni-directional (Fiberglass base station)
8.0 dBi
Fixed
2m
N/A
A24-F9NF
Omni-directional (Fiberglass base station)
9.5 dBi
Fixed
2m
N/A
A24-F10NF
Omni-directional (Fiberglass base station)
10 dBi
Fixed
2m
N/A
A24-F12NF
Omni-directional (Fiberglass base station)
12 dBi
Fixed
2m
N/A
A24-W7NF
Omni-directional (Fiberglass base station)
7.2 dBi
Fixed
2m
N/A
A24-M7NF
Omni-directional (Mag-mount base station)
7.2 dBi
Fixed
2m
N/A
A24-F15NF
Omni-directional (Fiberglass base station)
15.0 dBi
Fixed
2m
1 dB
Panel Antennas
A24-P8SF
Flat Panel
8.5 dBi
Fixed
2m
N/A
A24-P8NF
Flat Panel
8.5 dBi
Fixed
2m
N/A
A24-P13NF
Flat Panel
13.0 dBi
Fixed
2m
4.3 dB
A24-P14NF
Flat Panel
14.0 dBi
Fixed
2m
5.3 dB
A24-P15NF
Flat Panel
15.0 dBi
Fixed
2m
6.3 dB
A24-P16NF
Flat Panel
16.0 dBi
Fixed
2m
7.3 dB
A24-P19NF
Flat Panel
19.0 dBi
Fixed
2m
10.3 dB
A24-Y6NF
Yagi (6-element)
8.8 dBi
Fixed
2m
N/A
A24-Y7NF
Yagi (7-element)
9.0 dBi
Fixed
2m
N/A
A24-Y9NF
Yagi (9-element)
10.0 dBi
Fixed
2m
N/A
A24-Y10NF
Yagi (10-element)
11.0 dBi
Fixed
2m
0.1 dB
A24-Y12NF
Yagi (12-element)
12.0 dBi
Fixed
2m
1.1 dB
Yagi Antennas
Š 2014 Digi International Inc.
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XBee®/XBee‐PRO® ZB RF Modules
Part Number
Type (Description)
Gain
Application*
Min Separation
Minimum Cable
Loss/Power Reduction/Attenuation
Required
Channels 11-25
A24-Y13NF
Yagi (13-element)
12.0 dBi
Fixed
2m
1.1 dB
A24-Y15NF
Yagi (15-element)
12.5 dBi
Fixed
2m
1.6 dB
A24-Y16NF
Yagi (16-element)
13.5 dBi
Fixed
2m
2.6 dB
A24-Y16RM
Yagi (16-element, RPSMA connector)
13.5 dBi
Fixed
2m
2.6 dB
A24-Y18NF
Yagi (18-element)
15.0 dBi
Fixed
2m
4.1 dB
Antennas approved for use with the XBee ZB Surface Mount RF Module
Part Number
Type (Description)
Integral Antennas
29000313
Integral PCB antenna
A24-QI
Monopole (Integrated whip)
Dipole Antennas
A24-HASM-450
Dipole (Half-wave articulated RPSMA - 4.5”)
A24-HABSM
Dipole (Articulated RPSMA)
29000095
Dipole (Half-wave articulated RPSMA - 4.5”)
A24-HABUF-P5I
Dipole (Half-wave articulated bulkhead mount U.FL. w/ 5” pigtail)
A24-HASM-525
Dipole (Half-wave articulated RPSMA - 5.25")
Omni-directional Antennas
A24-F2NF
Omni-directional (Fiberglass base station)
A24-F3NF
Omni-directional (Fiberglass base station)
A24-F5NF
Omni-directional (Fiberglass base station)
A24-F8NF
Omni-directional (Fiberglass base station)
A24-F9NF
Omni-directional (Fiberglass base station)
A24-F10NF
Omni-directional (Fiberglass base station)
A24-F12NF
Omni-directional (Fiberglass base station)
A24-W7NF
Omni-directional (Fiberglass base station)
A24-M7NF
Omni-directional (Mag-mount base station)
A24-F15NF
Omni-directional (Fiberglass base station)
Panel Antennas
A24-P8SF
Flat Panel
A24-P8NF
Flat Panel
A24-P13NF
Flat Panel
A24-P14NF
Flat Panel
A24-P15NF
Flat Panel
A24-P16NF
Flat Panel
A24-P19NF
Flat Panel
Yagi Antennas
A24-Y6NF
Yagi (6-element)
A24-Y7NF
Yagi (7-element)
A24-Y9NF
Yagi (9-element)
A24-Y10NF
Yagi (10-element)
A24-Y12NF
Yagi (12-element)
A24-Y13NF
Yagi (13-element)
A24-Y15NF
Yagi (15-element)
A24-Y16NF
Yagi (16-element)
A24-Y16RM
Yagi (16-element, RPSMA connector)
A24-Y18NF
Yagi (18-element)
Š 2014 Digi International Inc.
Gain
Application*
Min. Separation
Minimum Cable Loss/
Power Reduction/Attenuation Required
Channels
11-25
Channel
26
0.0 dBi
1.5 dBi
Fixed/Mobile
Fixed/Mobile
20 cm
20 cm
N/A
N/A
N/A
N/A
2.1 dBi
2.1 dBi
2.1 dBi
2.1 dBi
2.1 dBi
Fixed
Fixed
Fixed/Mobile
Fixed/Mobile
Fixed
20 cm
20 cm
20 cm
20 cm
20 cm
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.1 dBi
3.0 dBi
5.0 dBi
8.0 dBi
9.5 dBi
10.0 dBi
12.0 dBi
7.2 dBi
7.2 dBi
15.0 dBi
Fixed/Mobile
Fixed/Mobile
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
20 cm
20 cm
20 cm
2m
2m
2m
2m
2m
2m
2m
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.0 dB
N/A
N/A
5.0 dB
8.5 dBi
8.5 dBi
13.0 dBi
14.0 dBi
15.0 dBi
16.0 dBi
19.0 dBi
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
2m
2m
2m
2m
2m
2m
2m
N/A
N/A
N/A
N/A
N/A
N/A
N/A
3.0 dB
3.0 dB
7.5 dB
8.5 dB
9.5 dB
10.5 dB
13.5 dB
8.8 dBi
9.0 dBi
10.0 dBi
11.0 dBi
12.0 dBi
12.0 dBi
12.5 dBi
13.5 dBi
13.5 dBi
15.0 dBi
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.8 dB
3.0 dB
4.0 dB
5.0 dB
6.0 dB
6.0 dB
6.5 dB
7.5 dB
7.5 dB
9.0 dB
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XBee®/XBee‐PRO® ZB RF Modules
Antennas approved for use with the XBee ZB Through Hole RF Module
Part Number
Type (Description)
Integral Antennas
29000294
Integral PCB antenna
A24-QI
Monopole (Integrated whip)
Dipole Antennas
A24-HASM-450
Dipole (Half-wave articulated RPSMA - 4.5”)
A24-HABSM
Dipole (Articulated RPSMA)
29000095
Dipole (Half-wave articulated RPSMA - 4.5”)
A24-HABUF-P5I
Dipole (Half-wave articulated bulkhead mount U.FL. w/ 5” pigtail)
A24-HASM-525
Dipole (Half-wave articulated RPSMA - 5.25")
Omni-directional Antennas
A24-F2NF
Omni-directional (Fiberglass base station)
A24-F3NF
Omni-directional (Fiberglass base station)
A24-F5NF
Omni-directional (Fiberglass base station)
A24-F8NF
Omni-directional (Fiberglass base station)
A24-F9NF
Omni-directional (Fiberglass base station)
A24-F10NF
Omni-directional (Fiberglass base station)
A24-F12NF
Omni-directional (Fiberglass base station)
A24-W7NF
Omni-directional (Fiberglass base station)
A24-M7NF
Omni-directional (Mag-mount base station)
A24-F15NF
Omni-directional (Fiberglass base station)
Panel Antennas
A24-P8SF
Flat Panel
A24-P8NF
Flat Panel
A24-P13NF
Flat Panel
A24-P14NF
Flat Panel
A24-P15NF
Flat Panel
A24-P16NF
Flat Panel
A24-P19NF
Flat Panel
Yagi Antennas
A24-Y6NF
Yagi (6-element)
A24-Y7NF
Yagi (7-element)
A24-Y9NF
Yagi (9-element)
A24-Y10NF
Yagi (10-element)
A24-Y12NF
Yagi (12-element)
A24-Y13NF
Yagi (13-element)
A24-Y15NF
Yagi (15-element)
A24-Y16NF
Yagi (16-element)
A24-Y16RM
Yagi (16-element, RPSMA connector)
A24-Y18NF
Yagi (18-element)
Gain
Application*
Min. Separation
Minimum Cable Loss/
Power Reduction/Attenuation Required
Channels
11-25
Channel
26
-0.5 dBi
1.5 dBi
Fixed/Mobile
Fixed/Mobile
20 cm
20 cm
N/A
N/A
N/A
N/A
2.1 dBi
2.1 dBi
2.1 dBi
2.1 dBi
2.1 dBi
Fixed
Fixed
Fixed/Mobile
Fixed/Mobile
Fixed
20 cm
20 cm
20 cm
20 cm
20 cm
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.1 dBi
3.0 dBi
5.0 dBi
8.0 dBi
9.5 dBi
10.0 dBi
12.0 dBi
7.2 dBi
7.2 dBi
15.0 dBi
Fixed/Mobile
Fixed/Mobile
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
20 cm
20 cm
20 cm
2m
2m
2m
2m
2m
2m
2m
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.0 dB
3.5 dB
4.0 dB
6.0 dB
1.2 dB
1.2 dB
9.0 dB
8.5 dBi
8.5 dBi
13.0 dBi
14.0 dBi
15.0 dBi
16.0 dBi
19.0 dBi
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
2m
2m
2m
2m
2m
2m
2m
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.5 dB
2.5 dB
7.0 dB
8.0 dB
9.0 dB
10.0 dB
13.0 dB
8.8 dBi
9.0 dBi
10.0 dBi
11.0 dBi
12.0 dBi
12.0 dBi
12.5 dBi
13.5 dBi
13.5 dBi
15.0 dBi
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
Fixed
2m
2m
2m
2m
2m
2m
2m
2m
2m
2m
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
2.8 dB
3 dB
4 dB
5 dB
6.5 dB
6.5 dB
6.5 dB
7.5 dB
7.5 dB
9.0 dB
* If using the RF module in a portable application (for example - if the module is used in a handheld device and the antenna is less than 20cm from
the human body when the device is in operation): The integrator is responsible for passing additional SAR (Specific Absorption Rate) testing based on
FCC rules 2.1091 and FCC Guidelines for Human Exposure to Radio Frequency Electromagnetic Fields, OET Bulletin and Supplement C. The testing
results will be submitted to the FCC for approval prior to selling the integrated unit. The required SAR testing measures emissions from the module and
how they affect the person.
RF Exposure
WARNING: To satisfy FCC RF exposure requirements for mobile transmitting devices, a separation distance of
20 cm or more should be maintained between the antenna of this device and persons during device operation.
To ensure compliance, operations at closer than this distance are not recommended. The antenna used for this
transmitter must not be co-located in conjunction with any other antenna or transmitter.
The preceding statement must be included as a CAUTION statement in OEM product manuals in order to alert users of FCC RF Exposure compliance.
Europe (ETSI)
The XBee RF Modules (excluding the PRO) have been certified for use in several European countries. For a
complete list, refer to www.digi.com
Š 2014 Digi International Inc.
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XBee®/XBee‐PRO® ZB RF Modules
If the XBee RF Modules are incorporated into a product, the manufacturer must ensure compliance of the
final product to the European harmonized EMC and low-voltage/safety standards. A Declaration of
Conformity must be issued for each of these standards and kept on file as described in Annex II of the
R&TTE Directive.
Furthermore, the manufacturer must maintain a copy of the XBee user manual documentation and ensure
the final product does not exceed the specified power ratings, antenna specifications, and/or installation
requirements as specified in the user manual. If any of these specifications are exceeded in the final
product, a submission must be made to a notified body for compliance testing to all required standards.
OEM Labeling Requirements
The 'CE' marking must be affixed to a visible location on the OEM product.
CE Labeling Requirements
The CE mark shall consist of the initials "CE" taking the following form:
•If the CE marking is reduced or enlarged, the proportions given in the above graduated drawing must
be respected.
•The CE marking must have a height of at least 5mm except where this is not possible on account of
the nature of the apparatus.
•The CE marking must be affixed visibly, legibly, and indelibly.
Restrictions
France: Outdoor use limited to 10 mW EIRP within the band 2454-2483.5 MHz.
Norway: Norway prohibits operation near Ny-Alesund in Svalbard. More information can be found at the
Norway Posts and Telecommunications site (www.npt.no).
Italy: For private use, a general authorization is required if WAS/RLANs are used outside own premises.
For public use, a general authorization is required.
Russian Federation:
• Maximum mean EIRP density is 2 mW/MHz, maximum 100 mW EIRP.
• Maximum mean EIRP density is 20 mW/MHz, maximum 100 mW EIRP permitted to use SRD
for outdoor applications only, for purposes of gathering telemetry information for automated
monitoring and resources accounting systems or security systems.
• Maximum mean EIRP density is 10 mW/MHz, maximum 100 mW EIRP for indoor applications.
Ukraine: EIRP must be less than or equal to 100 mW with built-in antenna, with amplification factor up to
6 dBi.
Declarations of Conformity
Digi has issued Declarations of Conformity for the XBee RF Modules concerning emissions, EMC and safety.
Files can be obtained by contacting Digi Support.
Important Note:
Digi does not list the entire set of standards that must be met for each country. Digi customers assume full
responsibility for learning and meeting the required guidelines for each country in their distribution market.
For more information relating to European compliance of an OEM product incorporating the XBee RF
Module, contact Digi, or refer to the following web sites:
CEPT ERC 70-03E - Technical Requirements, European restrictions and general requirements: Available at
www.ero.dk/.
R&TTE Directive - Equipment requirements, placement on market: Available at www.ero.dk/.
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XBee®/XBee‐PRO® ZB RF Modules
XBee RF Module
The following antennas have been tested and approved for use with the embedded XBee RF Module:
- Dipole (2.1 dBi, Omni-directional, Articulated RPSMA, Digi part number A24-HABSM)
- PCB Antenna (0.0 dBi)
- Monopole Whip (1.5 dBi)
Canada (IC)
Labeling Requirements
Labeling requirements for Industry Canada are similar to those of the FCC. A clearly visible label
the outside of the final product enclosure must display the following text.
on
For XBee ZB Surface Mount:
Contains Model XBee S2C Radio, IC: 1846A-XBS2C
The integrator is responsible for its product to comply with IC ICES-003 & FCC Part 15, Sub. B Unintentional Radiators. ICES-003 is the same as FCC Part 15 Sub. B and Industry Canada accepts FCC
test report or CISPR 22 test report for compliance with ICES-003.
For XBee-PRO ZB Surface Mount:
Contains Model XBee-PRO S2C Radio, IC: 1846A-XBPS2C
The integrator is responsible for its product to comply with IC ICES-003 & FCC Part 15, Sub. B Unintentional Radiators. ICES-003 is the same as FCC Part 15 Sub. B and Industry Canada accepts FCC
test report or CISPR 22 test report for compliance with ICES-003.
For XBee ZB Through Hole:
Contains Model S2CTH Radio, IC: 1846A-S2CTH
The integrator is responsible for its product to comply with IC ICES-003 & FCC Part 15, Sub. B Unintentional Radiators. ICES-003 is the same as FCC Part 15 Sub. B and Industry Canada accepts FCC
test report or CISPR 22 test report for compliance with ICES-003.
Transmitters for Detachable Antennas
This device has been designed to operate with the antennas listed in the previous table and having a
maximum of 19 dB. Antennas not included in this list or having a gain greater than 19 dB are strictly
prohibited for use with this device. The required antenna impedance is 50 ohms.
Detachable Antenna
To reduce potential radio interference to other users, the antenna type and gain should be so chosen that
the equivalent, istropically radiated power (EIRP) is not more than permitted for successful communication.
Australia (C-Tick)
These modules comply with requirements to be used in end products in Australia. All products with EMC
and radio communications must have a registered C-Tick mark. Registration to use the compliance mark
will only be accepted from Australian manufacturers or importers, or their agent, in Australia.
In order to have a C-Tick mark on an end product, a company must comply with a or b below.
a. have a company presence in Australia.
b. have a company/distributor/agent in Australia that will sponsor the importing of the end 
product.
Contact Digi for questions related to locating a contact in Australia.
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Appendix B: Migrating from XBee ZB to XBee
ZB RF Modules
The XBee ZB RF modules are designed to be compatible with the XBee ZB. The ZB SMT modules have all the features of
the ZB modules, and offer the increased feature set described in this user’s guide. For further information on the ZB, see
the XBee/XBee-PRO ZB RF Modules User’s Guide available at www.digi.com.
Pin Mapping
Mapping of the ZB SMT pins to the ZB pins is shown in the table below. The pin names are from the S2C SMT
module.
ZB SMT
Pin #
Name
GND
VCC
DOUT / DIO13
DIN / CONFIG / DIO14
DIO12
RESET
RSSI PWM / DIO10
PWM1 / DIO11
[reserved]
10
DTR / SLEEP_RQ / DIO8
11
GND
10
12
SPI_ATTN / BOOTMODE / DIO19
13
GND
14
SPI_CLK / DIO18
15
SPI_SSEL / DIO17
16
SPI_MOSI / DIO16
17
SPI_MISO / DIO15
18
[reserved]
19
[reserved]
20
[reserved]
21
[reserved]
22
GND
23
[reserved]
24
DIO4
11
25
CTS / DIO7
12
26
ON / SLEEP / DIO9
13
27
VREF
14
Š 2014 Digi International Inc.
ZB Pin #
162
XBee®/XBee‐PRO® ZB RF Modules
ZB SMT
Pin #
Name
ZB Pin #
28
ASSOCIATE / DIO5
15
29
RTS / DIO6
16
30
AD3 / DIO3
17
31
AD2 / DIO2
18
32
AD1 / DIO1
19
33
AD0 / DIO0
20
34
[reserved]
35
GND
36
RF
37
[reserved]
Mounting
One of the important differences between the ZB SMT and the ZB modules is the way they mount to the PCB.
The ZB is designed with through-hole pins, while the ZB SMT is designed with Surface Mount Technology (SMT).
As such, different mounting techniques are required.
Digi International has designed a footprint which will allow either module to be attached to a PCB. The layout is
shown below. All dimensions are in inches.
Š 2014 Digi International Inc.
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XBee®/XBee‐PRO® ZB RF Modules
The round holes in the diagram are for the ZB through-hole design, and the semi-oval pads are for the ZB SMT
design. Pin 1 of the through-hole design is lined up with pin 1 of the ZB SMT design, but the pins are actually
offset by one pad (see Pin Mapping above). By using diagonal traces to connect the appropriate pins, the layout
will work for both modules.
Information on attaching the ZB SMT module is included in Appendix C below.
Š 2014 Digi International Inc.
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Appendix C: Manufacturing Information
The XBee is designed for surface mount on the OEM PCB. It has castellated pads to allow for easy solder attach
inspection. The pads are all located on the edge of the module, so that there are no hidden solder joints on these
modules.
Recommended Solder Reflow Cycle
The recommended solder reflow cycle is shown below. The chart shows the temperature setting and the time to
reach the temperature. The cooling cycle is not shown.
Time (seconds)
Temperature (degrees C)
30
65
60
100
90
135
120
160
150
195
180
240
210
260
The maximum temperature should not exceed 260 degrees Celsius.
The module will reflow during this cycle, and therefore must not be reflowed updside down. Care should be
taken not to jar the module while the solder is molten, as parts inside the module can be removed from their
required locations.
Hand soldering is possible and should be done in accordance with approved standards.
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XBee®/XBee‐PRO® ZB RF Modules
Recommended Footprint
It is recommended that you use the PCB footprint shown below for surface mounting. Dimensions are in inches.
The solder footprint should be matched to the copper pads, but may need to be adjusted depending on the
specific needs of assembly and product standards.


While the underside of the module is mostly coated with solder resist, it is recommended that the copper layer
directly below the module be left open to avoid unintended contacts. Copper or vias must not interfere with the
three exposed RF test points on the bottom of the module (see below). Furthermore, these modules have a
ground plane in the middle on the back side for shielding purposes, which can be affected by copper traces
directly below the module.

&233(5
.((3287
Š 2014 Digi International Inc.
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XBee®/XBee‐PRO® ZB RF Modules
Flux and Cleaning
It is recommended that a “no clean” solder paste be used in assembling these modules. This will eliminate the
clean step and ensure unwanted residual flux is not left under the module where it is difficult to remove. In
addition:
• Cleaning with liquids can result in liquid remaining under the shield or in the gap between the
module and the OEM PCB. This can lead to unintended connections between pads on the module.
• The residual moisture and flux residue under the module are not easily seen during an inspection process.
Factory recommended best practice is to use a “no clean” solder paste to avoid the issues above and ensure
proper module operation.
Reworking
Rework should never be performed on the module itself. The module has been optimized to give the best
possible performance, and reworking the module itself will void warranty coverage and certifications. We
recognize that some customers will choose to rework and void the warranty; the following information is given
as a guideline in such cases to increase the chances of success during rework, though the warranty is still
voided.
The module may be removed from the OEM PCB by the use of a hot air rework station, or hot plate. Care should
be taken not to overheat the module. During rework, the module temperature may rise above its internal solder
melting point and care should be taken not to dislodge internal components from their intended positions.
Š 2014 Digi International Inc.
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Appendix D: Warranty Information
XBee RF Modules from Digi International, Inc. (the “Product”) are warranted against defects in materials and workmanship under normal use, for a period of 1-year from the date of purchase. In the event of a product failure due to
materials or workmanship, Digi will repair or replace the defective product. For warranty service, return the defective product to Digi International, shipping prepaid, for prompt repair or replacement.
The foregoing sets forth the full extent of Digi International’s warranties regarding the Product. Repair or replacement at Digi International’s option is the exclusive remedy. THIS WARRANTY IS GIVEN IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, AND DIGI SPECIFICALLY DISCLAIMS ALL WARRANTIES OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL DIGI, ITS SUPPLIERS OR LICENSORS BE LIABLE FOR
DAMAGES IN EXCESS OF THE PURCHASE PRICE OF THE PRODUCT, FOR ANY LOSS OF USE, LOSS OF TIME, INCONVENIENCE, COMMERCIAL LOSS, LOST PROFITS OR SAVINGS, OR OTHER INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PRODUCT, TO THE FULL EXTENT SUCH MAY
BE DISCLAIMED BY LAW. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES. THEREFORE, THE FOREGOING EXCLUSIONS MAY NOT APPLY IN ALL CASES. This warranty
provides specific legal rights. Other rights which vary from state to state may also apply.
Š 2014 Digi International Inc.
168
Appendix E: Definitions
Definitions
ZigBee Node Types
Coordinator
A node that has the unique function of forming a network. The coordinator is responsible for establishing the operating channel and PAN
ID for an entire network. Once established, the coordinator can form
a network by allowing routers and end devices to join to it. Once the
network is formed, the coordinator functions like a router (it can participate in routing packets and be a source or destination for data
packets).
------
One coordinator per PAN
Establishes/Organizes PAN
Can route data packets to/from other nodes
Can be a data packet source and destination
Mains-powered
Refer to the XBee coordinator section for more information.
Router
A node that creates/maintains network information and uses this
information to determine the best route for a data packet. A router
must join a network before it can allow other routers and end
devices to join to it.
A router can participate in routing packets and is intended to be a
mains-powered node.
-----
Several routers can operate in one PAN
Can route data packets to/from other nodes
Can be a data packet source and destination
Mains-powered
Refer to the XBee router section for more information.
End device
End devices must always interact with their parent to receive or
transmit data. (See ‘joining definition.) They are intended to sleep
periodically and therefore have no routing capacity.
An end device can be a source or destination for data packets but
cannot route packets. End devices can be battery-powered and offer
low-power operation.
-----
Š 2014 Digi International, Inc.
Several end devices can operate in one PAN
Can be a data packet source and destination 
All messages are relayed through a coordinator or router
Lower power modes
169
XBee®/XBee‐PRO® ZB RF Modules
ZigBee Protocol
PAN
Personal Area Network - A data communication network that
includes a coordinator and one or more routers/end devices.
Joining
The process of a node becoming part of a ZigBee PAN. A node
becomes part of a network by joining to a coordinator or a router
(that has previously joined to the network). During the process of
joining, the node that allowed joining (the parent) assigns a 16-bit
address to the joining node (the child).
Network Address
The 16-bit address assigned to a node after it has joined to another
node. The coordinator always has a network address of 0.
Operating Channel
The frequency selected for data communications between nodes. The
operating channel is selected by the coordinator on power-up.
Energy Scan
A scan of RF channels that detects the amount of energy present on
the selected channels. The coordinator uses the energy scan to
determine the operating channel.
Route Request
Broadcast transmission sent by a coordinator or router throughout
the network in attempt to establish a route to a destination node.
Route Reply
Unicast transmission sent back to the originator of the route request.
It is initiated by a node when it receives a route request packet and
its address matches the Destination Address in the route request
packet.
Route Discovery
The process of establishing a route to a destination node when one
does not exist in the Routing Table. It is based on the AODV (Ad-hoc
On-demand Distance Vector routing) protocol.
ZigBee Stack
ZigBee is a published specification set of high-level communication
protocols for use with small, low-power modules. The ZigBee stack
provides a layer of network functionality on top of the 802.15.4 specification.
For example, the mesh and routing capabilities available to ZigBee
solutions are absent in the 802.15.4 protocol.
Š 2014 Digi International, Inc.
170

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