AG Electronica XBee 2 Series User manual

XBee ZNet 2.5 (Formerly Series 2) - 1 mW, U.FL antenna
connector, 250000 bps, industrial grade (-40° C to 85° C)
Part Numbers:
North America: XB24-BUIT-004
International: XB24-BUIT-004

DCCharacteristicsoftheXBeeSeries2(VCC=2.8‐3.4VDC)
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355 South 520 West, Suite 180
Lindon, UT 84042
Phone: [phone]
Fax: [phone]
rf-xpert[email protected]
www.MaxStream.net (live chat support)
XBee™ Series 2 OEM RF Modules
XBee Series 2 Series 2 OEM RF Modules
ZigBee™Networks
RF Module Operation
RF Module Configuration
Appendices
Product Manual v1.x.2x - ZigBee Protocol
For OEM RF Module Part Numbers: XB24-BxIT-00x
ZigBee OEM RF Modules by MaxStream, Inc. - a Digi International brand
Firmware Versions: 1.0xx - Coordinator, Transparent Operation
1.1xx - Coordinator, API Operation
1.2xx - Router, End Device, Transparent Operation
1.3xx - Router, End Device, API Operation
90000866_B
2007.07.019
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XBeeSeries2OEMRFModules‐ZigBee‐v1.x2x[2007.07.019]
©2007DigiInternational,Inc. ii
© 2007 Digi International, Inc. All rights reserved
Nopartofthecontentsofthismanualmaybetransmittedorreproducedinany
formorbyanymeanswithoutthewrittenpermissionofDigiInternational,Inc.
ZigBee®isaregisteredtrademarkoftheZigBeeAlliance.
XBee™Series2isatrademarkofDigiInternational,Inc.
TechnicalSupport:Phone:(801)765‐9885
LiveChat:www.maxstream.net
E‐mail:rf‐[email protected]
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Contents
XBeeSeries2OEMRFModules‐ZigBee‐v1.x2x[2007.07.019]
©2007DigiInternaitonal,Inc. iii
1. XBee Series 2 OEM RF Modules 4
1.1. Key Features 4
1.1.1. Worldwide Acceptance 4
1.2. Specifications 5
1.3. Mechanical Drawings 6
1.4. Mounting Considerations 6
1.5. Pin Signals 7
1.6. Electrical Characteristics 8
2. RF Module Operation 9
2.1. Serial Communications 9
2.1.1. UART Data Flow 9
2.1.2. Serial Buffers 9
2.1.3. Serial Flow Control 10
2.1.4. Transparent Operation 12
2.1.5. API Operation 12
2.2. Modes of Operation 13
2.2.1. Idle Mode 13
2.2.2. Transmit Mode 13
2.2.3. Receive Mode 14
2.2.4. Command Mode 14
2.2.5. Sleep Mode 15
3. ZigBee Networks 17
3.1. ZigBee Network Formation 17
3.1.1. Starting a ZigBee Coordinator 17
3.1.2. Joining a Router 17
3.1.3. Joining an End Device 18
3.2. ZigBee Network Communications 19
3.2.1. ZigBee Device Addressing 19
3.2.2. ZigBee Application-layer Addressing 19
3.2.3. Data Transmission and Routing 20
4. XBee Series 2 Networks 25
4.1. XBee Series 2 Network Formation 25
4.1.1. Starting an XBee Series 2 Coordinator 25
4.1.2. Joining an XBee Series 2 Router to an ex-
isting PAN 25
4.1.3. Joining an XBee Series 2 End Device to an
Existing PAN 25
4.1.4. Network Reset 26
4.2. XBee Series 2 Addressing 27
4.2.1. Device Addressing 27
4.2.2. Application-layer Addressing 29
4.2.3. XBee Series 2 Binding Table 29
4.2.4. XBee Series 2 Endpoint Table 31
4.3. Sleep Mode Operation 32
4.3.1. End Device Operation 32
4.3.2. Parent Operation 32
4.4. I/O Line Configuration 32
5. Advanced Features 35
5.1. Device Discovery 35
5.2. Remote Configuration 35
5.3. Loopback Testing 35
5.3.1. AT Firmware 35
5.3.2. API Firmware 35
5.4. Join Indicators 35
5.5. Manual Device Identification 35
5.6. Battery Life Monitoring 36
6. XBee Series 2 Command Reference Tables37
7. API Operation 43
7.0.1. API Frame Specifications 43
7.0.2. API Frames 44
8. Examples 56
8.0.1. Starting an XBee Network 56
8.0.2. AT Command Programming Examples 57
8.0.3. API Programming Examples 57
9. Manufacturing Support 59
9.1. Interoperability with other EM250 Devic-
es 59
9.2. Customizing XBee Default Parameters
59
9.3. XBee Series 2 Custom Bootloader 59
9.4. Programming XBee Series 2 Modules 59
9.5. XBee EM250 Pin Mappings 59
Definitions 61
Agency Certifications 63
Migrating from the 802.15.4 Protocol 67
Development Guide 68
Additional Information 78
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©2007DigiInternational,Inc. 4
1.XBeeSeries2OEMRFModules
The XBee Series 2 OEM RF Modules were engineered to
operate within the ZigBee protocol and support the unique
needs of low-cost, low-power wireless sensor networks.
The modules require minimal power and provide reliable
delivery of data between remote devices.
The modules operate within the ISM 2.4 GHz frequency
band.
1.1. Key Features
1.1.1. Worldwide Acceptance
FCC Approval (USA) Refer to Appendix A [p50] for FCC Requirements.
Systems that contain XBee Series 2 RF Modules inherit MaxStream Certifications.
ISM (Industrial, Scientific & Medical) 2.4 GHz frequency band
Manufactured under ISO 9001:2000 registered standards
XBee Series 2 RF Modules are optimized for use in US, Canada, Australia, Israel
and Europe (contact MaxStream for complete list of agency approvals).
High Performance, Low Cost
• Indoor/Urban: up to 133’ (40 m)
• Outdoor line-of-sight: up to 400’ (120 m)
• Transmit Power: 2 mW (+3 dBm)
• Receiver Sensitivity: -96 dBm
RF Data Rate: 250,000 bps
Advanced Networking & Security
Retries and Acknowledgements
DSSS (Direct Sequence Spread Spectrum)
Each direct sequence channel has over
65,000 unique network addresses available
Point-to-point, point-to-multipoint
and peer-to-peer topologies supported
Self-routing, self-healing and fault-tolerant
mesh networking
Low Power
XBee Series 2
• TX Current: 40 mA (@3.3 V)
• RX Current: 40 mA (@3.3 V)
• Power-down Current: < 1 µA @ 25oC
Easy-to-Use
No configuration necessary for out-of box
RF communications
AT and API Command Modes for
configuring module parameters
Small form factor
Extensive command set
Free X-CTU Software
(Testing and configuration software)
Free & Unlimited Technical Support
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1.2. Specifications
*The ranges specified are typical when using the integrated Whip (1.5 dBi) and Dipole (2.1 dBi) antennas. The Chip
antenna option provides advantages in its form factor; however, it typically yields shorter range than the Whip and Dipole
antenna options when transmitting outdoors. For more information, refer to the “XBee Series 2 Antenna” application note
located on MaxStream’s web site
http://www.maxstream.net/support/knowledgebase/article.php?kb=153
Table1‐01. SpecificationsoftheXBeeSeries2OEMRFModule
Specification XBee Series 2
Performance
Indoor/Urban Range up to 133 ft. (40 m)*
Outdoor RF line-of-sight Range up to 400 ft. (120 m)*
Transmit Power Output
(software selectable) 2mW (+3dBm), boost mode enabled
1.25mW (+1dBm), boost mode disabled
RF Data Rate 250,000 bps
Serial Interface Data Rate
(software selectable) 1200 - 230400 bps (non-standard baud rates also supported)
Receiver Sensitivity -96 dBm, boost mode enabled
-95 dBm, boost mode disabled
Power Requirements
Supply Voltage 2.1 - 3.6 V
Operating Current (Transmit, max
output power) 40mA (@ 3.3 V, boost mode enabled)
35mA (@ 3.3 V, boost mode disabled)
Operating Current (Receive)) 40mA (@ 3.3 V, boost mode enabled)
38mA (@ 3.3 V, boost mode disabled)
Idle Current (Receiver off) 15mA
Power-down Current < 1 uA @ 25oC
General
Operating Frequency Band ISM 2.4 GHz
Dimensions 0.960” x 1.087” (2.438cm x 2.761cm)
Operating Temperature -40 to 85º C (industrial)
Antenna Options Integrated Whip, Chip, RPSMA, or U.FL Connector*
Networking & Security
Supported Network Topologies Point-to-point, Point-to-multipoint, Peer-to-peer & Mesh
Number of Channels
(software selectable) 16 Direct Sequence Channels
Addressing Options PAN ID and Addresses, Cluster IDs and Endpoints (optional)
Agency Approvals
United States (FCC Part 15.247) OUR-XBEE2
Industry Canada (IC) 4214A-XBEE2
Europe (CE) ETSI
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1.3. Mechanical Drawings
Figure1‐01. MechanicaldrawingsoftheXBeeSeries2OEMRFModules(antennaoptionsnotshown)
.
1.4. Mounting Considerations
The XBee Series 2 RF Module (through-hole) was designed to mount into a receptacle (socket) and
therefore does not require any soldering when mounting it to a board. The XBee Series 2
Development Kits contain RS-232 and USB interface boards which use two 20-pin receptacles to
receive modules.
Figure1‐02. XBeeSeries2ModuleMountingtoanRS‐232InterfaceBoard.
The receptacles used on MaxStream development boards are manufactured by Century
Interconnect. Several other manufacturers provide comparable mounting solutions; however,
MaxStream currently uses the following receptacles:
• Through-hole single-row receptacles -
Samtec P/N: MMS-110-01-L-SV (or equivalent)
• Surface-mount double-row receptacles -
Century Interconnect P/N: CPRMSL20-D-0-1 (or equivalent)
• Surface-mount single-row receptacles -
Samtec P/N: SMM-110-02-SM-S
MaxStream also recommends printing an outline of the module on the board to indicate the
orientation the module should be mounted.
XBee
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1.5. Pin Signals
Figure1‐03. XBeeSeries2RFModulePinNumber
(topsidesshown‐shieldsonbottom)
Design Notes:
• Minimum connections: VCC, GND, DOUT & DIN
• Minimum connections to support serial firmware upgrades: VCC, GND, DIN, DOUT, RTS & DTR
• Signal Direction is specified with respect to the module
• Module includes a 30k Ohm resistor attached to RESET
• Several of the input pull-ups can be configured using the PR command
• Unused pins should be left disconnected
Table1‐02. PinAssignmentsfortheXBeeSeries2Modules
(Low‐assertedsignalsaredistinguishedwithahorizontallineabovesignalname.)
Pin # Name Direction Description
1 VCC - Power supply
2 DOUT Output UART Data Out
3 DIN / CONFIG Input UART Data In
4 DIO12 Either Digital I/O 12
5RESET Input Module Reset (reset pulse must be at least 200 ns)
6 PWM0 / RSSI / DIO10 Either PWM Output 0 / RX Signal Strength Indicator / Digital IO
7 PWM / DIO11 Either Digital I/O 11
8 [reserved] - Do not connect
9DTR
/ SLEEP_RQ/ DIO8 Either Pin Sleep Control Line or Digital IO 8
10 GND - Ground
11 DIO4 Either Digital I/O 4
12 CTS / DIO7 Either Clear-to-Send Flow Control or Digital I/O 7
13 ON / SLEEP / DIO9 Output Module Status Indicator or Digital I/O 9
14 [reserved] - Do not connect
15 Associate / DIO5 Either Associated Indicator, Digital I/O 5
16 RTS / DIO6 Either Request-to-Send Flow Control, Digital I/O 6
17 AD3 / DIO3 Either Analog Input 3 or Digital I/O 3
18 AD2 / DIO2 Either Analog Input 2 or Digital I/O 2
19 AD1 / DIO1 Either Analog Input 1 or Digital I/O 1
20 AD0 / DIO0 / ID Button Either Analog Input 0, Digital I/O 0, or Node Identification
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1.6. Electrical Characteristics
Table1‐03. DCCharacteristicsoftheXBeeSeries2(VCC=2.8‐3.4VDC)
Symbol Parameter Condition Min Typical Max Units
VIL Input Low Voltage All Digital Inputs - - 0.2 * VCC V
VIH Input High Voltage All Digital Inputs 0.8 * VCC - 0.18* VCC V
VOL Output Low Voltage IOL = 2 mA, VCC >= 2.7 V - - 0.18*VCC V
VOH Output High Voltage IOH = -2 mA, VCC >= 2.7 V 0.82*VCC - - V
IIIN Input Leakage Current VIN = VCC or GND, all inputs, per pin - - 0.5uA uA
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©2007DigiInternational,Inc. 9
2.RFModuleOperation
2.1. Serial Communications
The XBee Series 2 OEM RF Modules interface to a host device through a logic-level asynchronous
serial port. Through its serial port, the module can communicate with any logic and voltage
compatible UART; or through a level translator to any serial device (For example: Through a
MaxStream proprietary RS-232 or USB interface board).
2.1.1. UART Data Flow
Devices that have a UART interface can connect directly to the pins of the RF module as shown in
the figure below.
Figure2‐01. SystemDataFlowDiagraminaUART‐interfacedenvironment
(Low‐assertedsignalsdistinguishedwithhorizontallineoversignalname.)
Serial Data
Data enters the module UART through the DIN (pin 3) 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.
Figure2‐02. UARTdatapacket0x1F(decimalnumberʺ31ʺ)astransmittedthroughtheRFmodule
ExampleDataFormatis8‐N‐1(bits‐parity‐#ofstopbits)
The module UART performs tasks, such as timing and parity checking, that are needed for data
communications. Serial communications depend on the two UARTs to be configured with
compatible settings (baud rate, parity, start bits, stop bits, data bits).
2.1.2. Serial Buffers
The XBee Series 2 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. The serial transmit buffer collects data that is received via
the RF link that will be transmitted out the UART.
DIN (data in) DIN (data in)
DOUT (data out) DOUT (data out)
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Figure2‐03. InternalDataFlowDiagram
Serial Receive Buffer
When serial data enters the RF module through the DIN Pin (pin 3), the data is stored in the serial
receive buffer until it can be processed. Under certain conditions, the module may not be able to
process data in the serial receive buffer immediately. If large amounts of serial data are sent to
the module, CTS flow control may be required to avoid overflowing the serial receive buffer.
Cases in which the serial receive buffer may become full and possibly overflow:
Serial Transmit Buffer
When RF data is received, the data is moved into the serial transmit buffer and is sent out the
serial 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
2.1.3. Serial 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.
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.
1. If the module is receiving a continuous stream of RF data, the data in the serial receive
buffer will not be transmitted until the module is no longer receiving RF data.
2. If the module is transmitting an RF data packet, the module may need to discover the des-
tination address or establish a route to the destination. After transmitting the data, the
module may need to retransmit the data if an acknowledgment is not received, or if the
transmission is a broadcast. These issues could delay the processing of data in the serial
receive buffer.
1. 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.
2. 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.
Serial
Receiver
Buffer
RF TX
Buffer Transmitter
RF Switch
Antenna
Port
Receiver
Serial Transmit
Buffer RF RX
Buffer
Processor
GND
DIN
VCC
DOUT
CTS
RTS
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RTS Flow Control
If flow RTS 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.
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2.1.4. Transparent Operation
RF modules that contain the following firmware versions will support Transparent Mode:
1.0xx (coordinator) and 1.2xx (router/end device).
When operating in Transparent Mode, the modules act as a serial line replacement. All UART data
received through the DIN pin is queued up for RF transmission. When RF data is received, the data
is sent out the DOUT pin. The module configuration parameters are configured using the AT
command mode interface. (See RF Module Operation --> Command Mode.)
When RF data is received by a module, the data is sent out the DOUT pin.
Serial-to-RF Packetization
Data is buffered in the serial receive buffer until one of the following causes the data to be
packetized and transmitted:
2.1.5. API Operation
API (Application Programming Interface) Operation is an alternative to the default Transparent
Operation. The frame-based API extends the level to which a host application can interact with the
networking capabilities of the module. RF modules that contain the following firmware versions will
support API operation: 1.1xx (coordinator) and 1.3xx (router/end device).
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 DIN pin (pin 3)) include:
• RF Transmit Data Frame
• Command Frame (equivalent to AT commands)
Receive Data Frames (sent out the DOUT pin (pin 2)) include:
• RF-received data frame
• Command response
• Event notifications such as reset, associate, disassociate, etc.
The API provides alternative means of configuring modules and routing data at the host
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.
The API operation option facilitates many operations such as the examples cited below:
To implement API operations, refer to the API Operation chapter 6.
1. No serial characters are received for the amount of time determined by the RO (Packetiza-
tion Timeout) parameter. If RO = 0, packetization begins when a character is received.
2. Maximum number of characters that will fit (72) in an RF packet is received.
3. The Command Mode Sequence (GT + CC + GT) is received. Any character buffered in the
serial receive buffer before the sequence is transmitted.
-> Transmitting data to multiple destinations without entering Command Mode
-> Receive success/failure status of each transmitted RF packet
-> Identify the source address of each received packet
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2.2. Modes of Operation
2.2.1. Idle Mode
When not receiving or transmitting data, the RF module is in Idle Mode. During Idle Mode, the RF
module is also checking for valid RF data. 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)
2.2.2. 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 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.
Figure2‐04. TransmitModeSequence
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. See Data
Transmission and Routing in chapter 3 for more information.
16-bit Network
Address Discovery
Data Discarded
Successful
Transmission
Yes
No
New
Transmission
16-bit Network
Address Discovered?
Route Known?
Route Discovered?
16-bit Network
Address Known?
Route Discovery
Transmit Data Idle Mode
No
Yes
No No
Yes Yes
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2.2.3. Receive Mode
If a valid RF packet is received, the data is transferred to the serial transmit buffer
2.2.4. 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. Refer to the API Mode
section for an alternate means of configuring modules.
AT Command Mode
To Enter AT Command Mode:
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]
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. Ensure the
‘Baud’ setting on the “PC Settings” tab matches the interface data rate of the RF module. By default,
the BD parameter = 3 (9600 bps).
To Send AT Commands:
Figure2‐05.SyntaxforsendingATCommands
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.
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.
System 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.
To Exit AT Command Mode:
For an example of programming the RF module using AT Commands and descriptions of each
configurable parameter, refer to the "Examples" and "XBee Series 2 Command Reference Tables"
chapters.
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.]
Send AT commands and parameters using the syntax shown below.
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.
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Chapter2‐RFModuleOperation
2.2.5. Sleep Mode
Sleep modes allow the RF module to enter states of low-power consumption when not in use. To
enter Sleep Mode, one of the following conditions must be met (in addition to the module having a
non-zero SM parameter value):
• Sleep_RQ (pin 9) is asserted
• The module is idle (no data is transmitted or received) for the time defined by the ST (Time
before Sleep) parameter.
The SM command is central to setting Sleep Mode configurations. By default, sleep modes are
disabled (SM=0) and the module remains in Idle/Receive Mode. When in this state, the module is
constantly ready to respond to serial or RF activity.
Zigbee Protocol: Sleep Modes
Pin/Host Controlled Sleep
Pin sleep puts the module to sleep and wakes it from sleep according to the state of Sleep_RQ
(pin 9). When Sleep_RQ is asserted (high), the module will finish any transmit or receive
operations, and then enter a low power state. The module will not respond to either serial or RF
activity while in sleep.
To wake a module operating in pin sleep, de-assert Sleep_RQ (pin 9). The module will wake when
Sleep_RQ is de-asserted and is ready to transmit or receive when the CTS line is low. When the
module wakes from pin sleep, it sends a transmission to its parent router or coordinator (called a
poll request) to see if it has buffered any data packets for the end device. The module will continue
to poll its parent for data while it remains awake. If the parent receives an RF data packet destined
for one or more of its end device children, it will transmit the packet to the end device upon receipt
of a poll request. See section 4.3, "Sleep Mode Operation" for more information.
Cyclic Sleep
Cyclic sleep allows modules to wake periodically to check for RF data and sleep when idle. When
the SM parameter is set to 4, the module is configured to sleep for the time specified by the SP
parameter. After the SP time expires, the module will wake and check for RF or serial data. To
check for RF data, the module sends a transmission to its parent router or coordinator (called a
poll request) to see if its parent has any buffered data packets for the end device. If the parent
has data for the module, the module will remain awake to receive the data. Otherwise, the module
will return to sleep. (See section 4.3, "Sleep Mode Operation" for more information.)
If serial or RF data is received, the module will start the ST timer and remain awake until the timer
expires. While the module is awake, it will continue to send poll request messages to its parent to
check for additional data. The ST timer will be restarted anytime serial or RF activity occurs. The
module will resume sleep when the ST timer expires.
When the module wakes from sleep, it asserts On/Sleep (pin 13) to provide a wake indicator to a
host device. If a host device wishes to sleep longer than SP time or to wake only when RF data
arrives, the SN command can be used to prevent On/Sleep from asserting for a multiple of SP
time. For example, if SP = 20 seconds, and SN = 5, the On/Sleep pin will remain de-asserted
(low) for up to 100 seconds.
Tab le2‐01. SleepModeConfigurations(Router/EndDeviceFirmwareOnly)
Sleep Mode
Setting
Transition
into Sleep
Mode
Transition out of
Sleep Mode (wake) Characteristics Related Commands Power Consumption
SM=1 Assert (high)
Sleep_RQ (pin 9) De-assert(0V)Sleep_RQ (pin 9) Pin/Host controlled SM < 1uA
SM=4
Automatic
transition to
sleep mode as
defined by the
ST parameter
Transitionoccursafterthe
cyclic sleep time interval
elapses.Thetime interval
is defined by the SP
(Cyclic Sleep Period)
parameter.
RF module wakes
after a pre-
determined time
intervaltodetectifRF
data is present.
SM, ST, SP, SN < 1uA
In the ZigBee protocol, sleep modes are only supported on end devices. See section 4.3, "Sleep
Mode Operation" for more information.
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If CTS flow control is enabled, CTS (pin 12) is asserted (0V) when the module wakes and de-
asserted (high) when the module sleeps, allowing for communication initiated by the host if
desired.
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3.ZigBeeNetworks
3.1. ZigBee Network Formation
A ZigBee Personal Area Network (PAN) consists of one coordinator and one or more routers and/or
end devices. A ZigBee Personal Area Network (PAN) is created when a coordinator selects a
channel and PAN ID to start on. Once the coordinator has started a PAN, it can allow router and
end device nodes to join the PAN.
When a router or end device joins a PAN, it receives a 16-bit network address and can transmit
data to or receive data from other devices in the PAN. Routers and the coordinator can allow other
devices to join the PAN, and can assist in sending data through the network to ensure data is
routed correctly to the intended recipient device. When a router or coordinator allows an end
device to join the PAN, the end device that joined becomes a child of the router or coordinator that
allowed the join.
End devices, however can transmit or receive data but cannot route data from one node to
another, nor can they allow devices to join the PAN. End devices must always communicate
directly to the parent they joined to. The parent router or coordinator can route data on behalf of
an end device child to ensure it reaches the correct destination. End devices are intended to be
battery powered and can support low power modes.
Figure3‐01. NodeTypes/SampleofaBasicZigBeeNetworkTopology
The network address of the PAN coordinator is always 0. When a router joins a PAN, it can also
allow other routers and end devices to join to it. Joining establishes a parent/child relationship
between two nodes. The node that allowed the join is the parent, and the node that joined is the
child. The parent/child relationship is not necessary for routing data.
3.1.1. Starting a ZigBee Coordinator
When a coordinator first comes up, it performs an energy scan on multiple channels (frequencies)
to select an unused channel to start the PAN. After removing channels with high detected energy
levels, the coordinator issues an 802.15.4 beacon request command on the remaining, low energy
level channels. Nearby routers or coordinators that have already joined a PAN respond to the
beacon request frame with a small beacon transmission indicating the PAN identifier (PAN ID) that
they are operating on, and whether or not they are allowing joining. The coordinator will attempt
to start on an unused PAN ID and channel. After starting, the coordinator may allow other devices
to join its PAN.
3.1.2. Joining a Router
When a router first comes up, it must locate and join a ZigBee PAN. To do this, it issues an
802.15.4 beacon request command on multiple channels to locate nearby PANs. Nearby routers
and coordinators that have already joined a PAN respond to the beacon request frame with a small
beacon transmission, indicating which channel and PAN ID they are operating on. The router
listens on each channel for these beacon frames. If a valid PAN is found from one of the received
beacons, the router issues a join request to the device that sent the beacon. If joining succeeds,
the router will then receive a join confirmation from the device, indicating the join was successful.
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Once the router joins the PAN, it can communicate with other devices on the PAN and allow new
devices to join to it.
3.1.3. Joining an End Device
When an end device first comes up, it must also locate and join a PAN. End devices follow the
same process as a router to join a PAN. Once the end device has successfully joined a PAN, it can
communicate with other devices on the PAN. However, since end devices cannot route data, they
must always communicate directly with their parent and allow the parent to route data in its
behalf.
Figure3‐02. DemonstrationofBeaconRequestandBeacontransmissionsthattakeplaceduringjoining.
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Chapter3‐ZigBeeNetworks
3.2. ZigBee Network Communications
Zigbee supports device addressing and application layer addressing. Device addressing specifies
the destination address of the device a packet is destined to. Application layer addressing indicates
a particular application recipient, known as a Zigbee endpoint, along with a message type field
called a Cluster ID.
3.2.1. ZigBee Device Addressing
The 802.15.4 protocol upon which the ZigBee protocol is built specifies two address types:
• 16-bit network addresses
• 64-bit Addresses
16-bit Network Addresses
A 16-bit network address is assigned to a node when the node joins a network. The network
address is unique to each node in the network. However, network addresses are not static - it can
change.
The following two conditions will cause a node to receive a new network address:
ZigBee requires that data be sent to the 16-bit network address of the destination device. This
requires that the 16-bit address be discovered before transmitting data. See 3.2.3 Network
Address Discovery for more information.
64-bit Addresses
Each node contains a unique 64-bit address. The 64-bit address uniquely identifies a node and is
permanent.
3.2.2. ZigBee Application-layer Addressing
The ZigBee application layers define endpoints and cluster identifiers (cluster IDs) that are used to
address individual services or applications on a device. An endpoint is a distinct task or application
that runs on a ZigBee device, similar to a TCP port. Each ZigBee device may support one or more
endpoints. Cluster IDs define a particular function or action on a device. Cluster IDs in the ZigBee
home controls lighting profile, for example, would include actions such as “TurnLightOn”,
“TurnLightOff”, “DimLight”, etc.
Suppose a single radio controls a light dimmer and one or more light switches. The dimmer and
switches could be assigned to different endpoint values. To send a message to the dimmer, a
remote radio would transmit a message to the dimmer endpoint on the radio. In this example, the
radio might support cluster IDs to “TurnLightOn”, “TurnLightOff”, or “DimLight”. Thus, for radio A to
turn off a light on radio B, radio A would send a transmission to the light switch endpoint on radio
B, using cluster ID “TurnLightOff”. This is shown in the figure below.
1. If an end device cannot communicate with its parent it may need to leave the network and
rejoin to find a new parent.
2. If the device type changes from router to end device, or vice-versa, the device will leave
the network and rejoin as the new device type.
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