Digi PS2CSM User manual

Digi International Inc.
11001 Bren Road East
Minnetonka, MN 55343
877 912-3444 or 952 912-3444
www.digi.com
XBee®/XBee-PRO®ZB RF Modules
ZigBee RF Modules by Digi International
Models: XBEE S2C, PS2CSM, S2CTH, PS2CTH, Legacy PRO S2C
Hardware: S2C
Firmware: 401x, 402x, 403x, 404x, 405x
90002002_P
10/10/2014

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 2
© 2014 Digi International Inc. All rights reserved.
Digi, Digi International, the Digi logo, XBee®and XBee-PRO®are trademarks or registered trademarks of Digi International
Inc. in the United Sates and other countries worldwide. ZigBee®is a registered trademark of the ZigBee alliance. 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.
For basic information to help get you started on the XBee/XBee-PRO ZB RF Module, navigate to the Getting Started Guide at
digi.com/support. Enter the keyword 'XBee-PRO ZB' and select the Documentation tab. Under the Documentation tab, you
will find the XBee-PRO ZB RF Module Development Kit Getting Started Guide.
Technical Support: Phone: [phone] toll-free U.S.A. & Canada
[phone] Worldwide
8:00 am - 5:00 pm [U.S. Mountain Time]
Online Support: www.digi.com/support/eservice

Contents
XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 3
Overview of the XBee ZigBee RF Module 7
Worldwide Acceptance 7
What’s New in 40xx Firmware 7
Specifications of the XBee ZigBee RF Module 8
Hardware Specifications 8
Agency Approvals 9
Serial Communications Specifications of the XBee
ZigBee RF Module 9
UART 9
SPI 9
GPIO Specifications 9
Hardware Specifications for Programmable Variant
10
Mechanical Drawings of the XBee ZigBee RF Modules
11
Pin Signals for the XBee ZigBee Surface Mount Mod-
ule 14
Pin Signals for the XBee ZigBee Through-hole Module
15
EM357 Pin Mappings 16
Design Notes for the XBee ZigBee RF Module 16
Power Supply Design 16
Recommended Pin Connections 16
Board Layout 17
Module Operation for Programmable Variant 21
XBee Programmable Bootloader 24
Overview 24
Bootloader Software Specifics 24
Bootloader Menu Commands 30
Firmware Updates 31
Output File Configuration 32
XBee ZigBee RF Module Operation 33
XBee ZigBee Serial Communications 33
UART Data Flow 33
XBee ZigBee SPI Communications 33
XBee ZigBee Serial Buffers 35
UART Flow Control 35
XBee ZigBee Break Control 36
Serial Interface Protocols 36
XBee ZigBee Modes of Operation 38
Idle Mode 38
Transmit Mode 38
Receive Mode 39
Command Mode 39
Sleep Mode 40
XBee ZigBee Networks 41
Introduction to ZigBee 41
ZigBee Stack Layers 41
ZigBee Networking Concepts 41
Device Types 41
PAN ID 43
Operating Channel 43
ZigBee Application Layers: In Depth 43
Application Support Sublayer (APS) 43
Application Profiles 43
ZigBee Coordinator Operation 45
Forming a Network 45
Channel Selection 45
PAN ID Selection 45
Security Policy 45
Persistent Data 45
XBee ZigBee Coordinator Startup 45
Permit Joining 46
Resetting the Coordinator 47
Leaving a Network 47
Replacing a Coordinator (Security Disabled Only) 47
Example: Starting a Coordinator 48
Example: Replacing a Coordinator (Security Disabled) 48
ZigBee Router Operation 48
Discovering ZigBee Networks 48
Joining a Network 49
Authentication 49
Persistent Data 49
XBee ZB Router Joining 49
Permit Joining 50
Joining Always Enabled 50
Joining Temporarily Enabled 50
Router Network Connectivity 50
Leaving a Network 52
Network Locator Option 52
Resetting the Router 53
Example: Joining a Network 53
End Device Operation 53
Discovering ZigBee Networks 53
Joining a Network 54
Parent Child Relationship 54
End Device Capacity 54
Authentication 54
Persistent Data 54

Contents
XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 4
Orphan Scans 54
XBee ZigBee End Device Joining 55
Parent Connectivity 55
Resetting the End Device 56
Leaving a Network 56
Example: Joining a Network 56
ZigBee Channel Scanning 56
Managing Multiple ZigBee Networks 57
PAN ID Filtering 57
Pre-configured Security Keys 57
Permit Joining 57
Application Messaging 57
Transmission, Addressing, and Routing 58
Addressing 58
64-bit Device Addresses 58
16-bit Device Addresses 58
Application Layer Addressing 58
Data Transmission 58
Broadcast Transmissions 59
Unicast Transmissions 59
Binding Transmissions 61
Multicast Transmissions 61
Fragmentation 61
Data Transmission Examples 62
RF Packet Routing 64
Link Status Transmission 64
AODV Mesh Routing 65
Many-to-One Routing 67
High/Low Ram Concentrator Mode 68
Source Routing 68
Encrypted Transmissions 71
Maximum RF Payload Size 71
Throughput 72
Latency Timing Specifications 72
ZDO Transmissions 72
ZigBee Device Objects (ZDO) 72
Sending a ZDO Command 73
Receiving ZDO Commands and Responses 73
Transmission Timeouts 75
Unicast Timeout 75
Extended Timeout 75
Transmission Examples 76
XBee ZigBee Security 78
Security Modes 78
ZigBee Security Model 78
Network Layer Security 78
Frame Counter 79
Message Integrity Code 79
Network Layer Encryption and Decryption 79
Network Key Updates 79
APS Layer Security 79
Message integrity Code 80
APS Link Keys 80
APS Layer Encryption and Decryption 80
Network and APS Layer Encryption 80
Trust Center 81
Forming and Joining a Secure Network 81
Implementing Security on the XBee 81
Enabling Security 82
Setting the Network Security Key 82
Setting the APS Trust Center Link Key 82
Enabling APS Encryption 82
Using a Trust Center 82
XBee Security Examples 83
Example 1: Forming a network with security (pre-con-
figured link keys) 83
Example 2: Forming a network with security (obtain-
ing keys during joining) 83
Network Commissioning and Diagnostics 85
Device Configuration 85
Device Placement 85
Link Testing 85
RSSI Indicators 86
Device Discovery 86
Network Discovery 86
ZDO Discovery 86
Joining Announce 86
Commissioning Pushbutton and Associate LED 86
Commissioning Pushbutton 87
Associate LED 88
Binding 89
Group Table API 91
Managing End Devices 101
End Device Operation 101
Parent Operation 101
End Device Poll Timeouts 102
Packet Buffer Usage 102

Contents
XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 5
Non-Parent Device Operation 102
XBee End Device Configuration 103
Pin Sleep 103
Cyclic Sleep 105
Transmitting RF Data 108
Receiving RF Data 108
I/O Sampling 109
Waking End Devices with the Commissioning Pushbut-
ton 109
Parent Verification 109
Rejoining 109
XBee Router/Coordinator Configuration 109
RF Packet Buffering Timeout 110
Child Poll Timeout 110
Transmission Timeout 110
Putting It All Together 111
Short Sleep Periods 111
Extended Sleep Periods 111
Sleep Examples 111
XBee Analog and Digital I/O Lines 113
XBee ZB Through Hole RF Module 113
I/O Configuration 114
I/O Sampling 115
Queried Sampling 116
Periodic I/O Sampling 116
Change Detection Sampling 116
RSSI PWM 117
I/O Examples 117
PWM1 117
XBee ZigBee API Operation 118
API Frame Specifications 118
API Examples 120
API Serial Port Exchanges 121
AT Commands 121
Transmitting and Receiving RF Data 121
Remote AT Commands 121
Source Routing 122
Supporting the API 122
API Frames 122
AT Command 122
AT Command - Queue Parameter Value 123
ZigBee Transmit Request 123
Explicit Addressing ZigBee Command Frame 125
Remote AT Command Request 127
Create Source Route 128
AT Command Response 129
Modem Status 129
ZigBee Transmit Status 130
ZigBee Receive Packet 131
ZigBee Explicit Rx Indicator 132
ZigBee IO Data Sample Rx Indicator 133
XBee Sensor Read Indicator 134
Node Identification Indicator 136
Remote Command Response 137
Extended Modem Status 137
Over-the-Air Firmware Update Status 140
Route Record Indicator 142
Many-to-One Route Request Indicator 143
Sending ZigBee Device Objects (ZDO) Commands
with the API 144
Sending ZigBee Cluster Library (ZCL) Commands
with the API 146
Sending Public Profile Commands with the API 148
XBee Command Reference Tables 151
XBee ZigBee Module Support 162
XCTU Configuration Tool 162
Customizing XBee ZB Firmware 162
Design Considerations for Digi Drop-In Networking
162
XBee Bootloader 162
Programming XBee Modules 163
Serial Firmware Updates 163
Invoke XBee Bootloader 163
Send Firmware Image 163
Writing Custom Firmware 163
Regulatory Compliance 163
Enabling GPIO 1 and 2 164
Detecting XBee vs. XBee-PRO 164
Special Instructions For Using the JTAG Interface 164
Appendix A: Agency Certifications 166
United States FCC 166
OEM Labeling Requirements 166
FCC Notices 166
FCC-Approved Antennas (2.4 GHz) 167
Europe (ETSI) 172
OEM Labeling Requirements 172
Restrictions 172
Declarations of Conformity 172

Contents
XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 6
Antennas 173
Canada (IC) 173
Transmitters for Detachable Antennas 173
Detachable Antenna 173
Australia (RCM/C-Tick) 174
Appendix B:Migrating from XBee Through-hole to
XBee Surface Mount Modules 175
Appendix C:Manufacturing Information 178
Appendix D:Warranty Information 181
Appendix E:Definitions 182

©2014DigiInternationalInc. 7
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.
XBee®and XBee-PRO®ZB embedded RF modules provide wireless connectivity to end-point devices in ZigBee mesh
networks. Utilizing the ZigBee PRO Feature Set, these modules are inter-operable 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 additional development.
The XBee/XBee-PRO ZB modules are compatible with other devices that use XBee ZB technology. These include Connect-
PortX 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/XBee-PRO 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, Australia, Europe (XBee
only) and Japan (XBee only). Contact Digi for a 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 com-
mand 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 dis-
abled 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)

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 8
Specifications of the XBee ZigBee RF Module
Hardware Specifications
SpecificationsoftheXBee®/XBee‐PRO®ZBRFModule
Specification XBee ZB XBee-PRO ZB
Performance
Indoor/Urban Range Up to 200 ft. (60 m) Up to 300 ft. (90 m)
Outdoor RF line-of-sight Range Up to 4000 ft. (1200 m) Up to 2 miles (3200 m)
Transmit Power Output 
(maximum)
6.3mW (+8dBm), Boost mode
3.1mW (+5dBm), Normal mode
Channel 26 max power is +3dBm
63mW (+18 dBm)
RF Data Rate 250,000 bps
Receiver Sensitivity -102 dBm, Boost mode
-100 dBm, Normal mode -101 dBm
Power Requirements
Adjustable Power Yes
Supply Voltage 2.1 - 3.6 V
2.2 - 3.6 V for Programmable Version 2.7 - 3.6 V
Operating Current (Transmit) 45mA (+8 dBm, Boost mode)
33mA (+5 dBm, Normal mode) 120mA @ +3.3 V, +18 dBm
Operating Current (Receive) 31mA (Boost mode)
28mA (Normal mode) 31mA
Power-down Current < 1 µA @ 25°C
General
Operating Frequency Band ISM 2.4 - 2.5 GHz
Form Factor Through-Hole, Surface Mount
Dimensions Through-Hole: 0.960 x 1.087 in (2.438 x 2.761 cm)
SMT: 0.866 x 1.33 x 0.120 in (2.199 x 3.4 x 0.305 cm)
Through-Hole: 0.960 x 1.297 in (2.438 x 3.294 cm)
SMT: 0.866 x 1.33 x 0.120 in (2.199 x 3.4 x 0.305 cm)
Operating Temperature -40 to 85°C (industrial)
Antenna Options Through-Hole: PCB Antenna, U.FL Connector, RPSMA Connector, or Integrated Wire
SMT: RF Pad, PCB Antenna, or U.FL Connector
Networking & Security
Supported Network Topologies Point-to-point, Point-to-multipoint, Peer-to-peer, and Mesh
Number of Channels 16 Direct Sequence Channels 15 Direct Sequence Channels
Interface Immunity DSSS (Direct Sequence Spread Spectrum)
Channels 11 to 26 11 to 25
Addressing Options PAN ID and Addresses, Cluster IDs and Endpoints (optional)
Interface Options
UART 1 Mbps maximum (burst)
SPI 5 Mbps maximum (burst)

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 9
Agency Approvals
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.
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.
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.
AgencyApprovals
Approval XBee (Surface Mount) XBee-PRO (Surface
Mount) XBee (Through-hole) XBee-PRO (Through-hole)
United States (FCC
Part 15.247) FCC ID: MCQ-XBS2C FCC ID: MCQ-PS2CSM FCC ID: MCQ-S2CTH FCC ID: MCQ-PS2CTH
Industry Canada (IC) IC: 1846A-XBS2C IC: 1846A-PS2CSM IC: 1846A-S2CTH IC: 1846A-PS2CTH
FCC/IC Test Transmit
Power Output range -26 to +8 dBm -0.7 to +19.4 dBm -26 to +8 dBm +1 to +19 dBm
Europe (CE) ETSI ETSI
Australia C-Tick RCM RCM RCM
Japan R201WW10215369 Pending
RoHS Compliant
UARTPinAssignments
Specifications Module Pin Number
UART Pins XBee (Surface Mount) XBee (Through-hole)
DOUT 3 2
DIN / CONFIG 43
CTS / DIO7 25 12
RTS / DIO6 29 16
SPIPinAssignments
Specifications Module Pin Number
SPI Pins XBee (Surface Mount) XBee (Through-hole)
SPI_SCLK 14 18
SPI_SSEL 15 17
SPI_MOSI 16 11
SPI_MISO 17 4

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 10
See GPIO section for more information on configuring and using GPIO ports.
Hardware Specifications for Programmable Variant
If the module has the programmable secondary processor, add the following table values to the specifications
listed on page 8. For example, if the secondary processor is running at 20 MHz and the primary processor is in
receive 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 receive current of the primary.
ElectricalSpecificationsforGPIOLines
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)
Output source/sink 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/sink current for pin numbers 2, 3, 4, 9, 12, 13, 15, 16, 17,
and 19 on the TH modules 4 mA
Output source/sink current for pad numbers 7, 8, 24, 31, and 33 on the
SMT modules 8 mA
Output source/sink current for pin numbers 6, 7, 11, 18, and 20 on the TH
modules 8 mA
Total output current (for GPIO pads) 40 mA
Specificationsoftheprogrammablesecondaryprocessor
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
©2014DigiInternationalInc. 11
Mechanical Drawings of the XBee ZigBee RF Modules
MechanicaldrawingsoftheXBee®/XBee‐PRO®ZBRFModules.Alldimensionsareininches.
MechanicaldrawingsoftheXBee/XBee‐PROSMTmodel(antennaoptionsnotshown).
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XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 12
MechanicaldrawingsoftheXBeeTHmodel
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XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 13
MechanicaldrawingsoftheXBee‐PROTHmodel
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XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 14
Pin Signals for the XBee ZigBee Surface Mount Module
• 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
PinAssignmentsforXBeeSurfaceMountModules
(Low‐assertedsignalsaredistinguishedwithahorizontallineabovesignalname.)
Pin # Name Direction Default State Description
1 GND - - Ground
2 VCC - - Power Supply
3 DOUT / DIO13 Both Output UART Data Out / GPIO
4 DIN / CONFIG / DIO14 Both Input UART Data In / GPIO
5 DIO12 Both GPIO
6 RESET Input Module Reset
7 RSSI PWM / DIO10 Both Output RX Signal Strength Indicator / GPIO
8 PWM1 / DIO11 Both Disabled Pulse Width Modulator / GPIO
9 [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 / Commissioning Button
34 [reserved] - Disabled Do Not Connect
35 GND - - Ground
36 RF Both - RF IO for RF Pad Variant
37 [reserved] - Disabled Do Not Connect

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 15
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 Description
1 VCC - - Power Supply
2 DOUT / DIO13 Both Output UART Data Out
3 DIN / CONFIG / DIO14 Both Input UART Data In
4 DIO12 / SPI_MISO Both Disabled GPIO/ SPI slave out
5 RESET Input Input Module Reset
6 RSSI PWM / PWMO DIO10 Both Output RX signal strength indicator / GPIO
7 PWM1 / DIO11 Both Disabled GPIO
8 [reserved] - - Do Not Connect
9DTR
/ SLEEP_RQ / DIO8 Both Input Pin Sleep Control Line / GPIO
10 GND - - Ground
11 SPI_MOSI / DIO4 Both Disabled GPIO/ SPI slave in
12 CTS / DIO7 Both Output Clear-to-Send Flow Control / GPIO
13 ON_SLEEP / DIO9 Both Output Module Status Indicator / GPIO
14 VREF - - Not connected
15 ASSOCIATE / DIO5 Both Output Associate Indicator / GPIO
16 RTS / DIO6 Both Input Request to Send Flow Control / GPIO
17 AD3 / DIO3 / SPI_SSEL Both Disabled Analog Input / GPIO / SPI Slave Select
18 AD2 / DIO2 / SPI_CLK Both Disabled Analog Input / GPIO / SPI Clock
19 AD1 / DIO1 / SPI_ATTN Both Disabled Analog Input / GPIO / SPI Attention
20 AD0 / DIO0 / CB Both Disabled Analog Input / GPIO / Commissioning Button

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 16
EM357 Pin Mappings
The following table shows how the EM357 pins are used on the XBee.
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 (pad 2/SMT, pin 1/TH) 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
(pad 2/SMT, pin 1/TH) of the module. The nearest proximity to (pad 2/SMT, pin 1/TH) 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.
EM357 Pin # EM357 Pin Name XBee (SMT) Pad # XBee (TH) Pin # Other Usage
12 RST 6 5 Programming
18 PA7 8 7
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 4 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 7 6
30 PB1 / SC1TXD 3 2 Used for UART
31 PB2 / SC1RXD 4 3 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 5 4 JTAG (see Writing Custom Firmware section)
36 PB0 10 9
38 PC1 / ADC3 30 17
41 PB7 / ADC2 31 18
42 PB6 / ADC1 33 20
43 PB5 / ADC0 Temperature sensor on PRO version

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 17
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/SMT, pin 15/TH) and the Commissioning pad (pad 33/SMT, pin 20/TH). 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. 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 pin
numbers 2, 3, 4, 9, 12, 13, 15, 16, 17, and 19, and 8mA for pin 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 drawings on the
following pages illustrate important recommendations when designing with PCB antenna modules. 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.

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 18
SMT Keepout Area

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 19
TH Keepout Area

XBee®/XBee‐PRO®ZBRFModules
©2014DigiInternationalInc. 20
Design Notes for SMT 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. 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