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ZB2430
User Manual
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AeroComm ZB2430 User Manual

V ERSION 2.0
Technical Support: Phone: 800.492.2320
E-mail: wireless.support@lairdtech.com
Web: www.aerocomm.com/
Sales: Phone: 800.492.2320
E-mail: wireless.sales@lairdtech.com
Web: www.aerocomm.com
Document Information
Copyright © 2008 AeroComm, Inc. All rights reserved.
All brands and product names in this publication are registered trademarks or trademarks of their respective holders.
This material is preliminary
Information furnished by AeroComm in this specification is believed to be accurate. Devices sold by AeroComm are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. AeroComm makes no warranty, express, statutory, and implied or by description, regarding the information set forth herein. AeroComm reserves the right to change specifications at any time and without notice.
AeroComm’s products are intended for use in normal commercial and industrial applications. Applications requiring unusual environmental requirements such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional testing for such application.
Limited Warranty, Disclaimer, Limitation of Liability
For a period of one (1) year from the date of purchase by the OEM customer, AeroComm warrants the OEM transceiver against defects in materials and workmanship. AeroComm will not honor this warranty (and this warranty will be automatically void) if there has been any (1) tampering, signs of tampering; 2) repair or attempt to repair by anyone other than an AeroComm authorized technician.
This warranty does not cover and AeroComm will not be liable for, any damage or failure caused by misuse, abuse, acts of God, accidents, electrical irregularity, or other causes beyond AeroComm’s control, or claim by other than the original purchaser.
In no event shall AeroComm be responsible or liable for any damages arising: From the use of product; From the loss of use, revenue or profit of the product; or As a result of any event, circumstance, action, or abuse beyond the control of AeroComm, whether such damages be direct, indirect, consequential, special or otherwise and whether such damages are incurred by the person to whom this warranty extends or third party.
If, after inspection, AeroComm determines that there is a defect, AeroComm will repair or replace the OEM transceiver at their discretion. If the product is replaced, it may be a new or refurbished product.
Revision History
Revision Description
Version 1.0 7/21/06 - Initial Release Version
Version 1.1 7/25/06 - Updated Pin definitions, corrected status request
command to display 0x00 as firmware version, updated CC 08, CC 21 and EEPROM byte write commands. Corrected PAN ID EEPROM address to address 0x78. Updated Future Enhancements section.
Version 1.2 9/15/06 - Changed Reset to active Low. Changed pin 20 to
Sleep pin and is active Low. Added second mechanical drawing.
Version 1.3 1/18/07 - Corrected Read Temperature command.
Version 1.4 7/6/07 - Internal Release.
Version 1.5 7/17/07 - Added pinout for pluggable module.
Version 1.6 8/24/07 - Added API command set. Added Neighbor, Route, &
Radio Table commands. Added Energy scan command. Added NV with soft reset command. Added static network parameters information. Updated Broadcast section. Updated Serial Interface section. Updated Channel Mask section. Added power-down modes. Corrected status request response. Added MAC retries to EEPROM parameter list.
Version 1.7 Corrected Read Channel Command (was CC 02 00; changed to
CC 02)
Version 1.8 12/17/07 - Updated Compliancy Information. Added approval for
ZB2430-D. Updated Approved Antenna List.
Version 1.9 1/4/08 - Added new EEPROM parameters for firmware version
1.6 - End Device poll rate, Parent Hold Message, End Device Wake Time, End Device Wake Poll rate, Stop Bit Delay, Modify Wake upon RX, Reload Sleep, NV Restore enable/disable, & RS485 DE/RE.
Version 2.0 3/1/08- Updated ZB2430 Features, Updated Current Draw for
High Power module, Updated RF Packet Size in RX Data Buffer and CTS, Updated Write Digital Output, Removed Discover 16-bit NWK Address command, Added Read Voltage cmd, Added Restore Default cmd, Added End-to-End Retries to EEPROM Parameters Table, Updated CTS On/Off Thresholds, Updated Read Neighbor Table Command
Updated Read Digital Input, Updated Read ADC,
Contents
ZB2430 TRANSCEIVER MODULE 1
ZB2430 Features 1 Overview 1
SPECIFICATIONS 2
Pin Definitions 4
HARDWARE INTERFACE 6
Pin Definitions 6
Generic I/O 6 RXD and TXD 6 Test/Sleep Int. 6 UP_Reset 6 Command/Data 6 In Range 6 RTS Handshaking* 6 CTS Handshaking 7 Sleep Ind. 7 AD In 7
TERMS & DEFINITIONS 8
THEORY OF OPERATION 11
IEEE 802.15.4 & ZigBee Overview 11 Creating a Network 12
Mesh 12 Parent/Child Relationship 13 Network Limitations 14
Maximum Network Depth 14
Maximum Number of Children per Parent 15 ZigBee Addressing 15
16-bit Network Address 15
64-bit MAC address 16
Mesh Routing (AODV) 16
Coordinator Addressing 18
Broadcast Transmissions 18
CONFIGURING THE ZB2430 28
AT Commands 29
On-the-Fly Control Commands 29
Command Descriptions 31
EEPROM PARAMETERS 37
API OPERATION 41
API Transmit Packet 41 API Send Data Complete 41 API Receive Packet 42
ZB2430 ADDRESSING 43
ADVANCED NETWORK COMMANDS 45
Read Neighbor Table 45 Read Route Table 47 Perform Scan 49 Read Radio Table 51
DIMENSIONS 53
ZB2430 Mechanical 53
ORDERING INFORMATION 54
Product Part Numbers 54
COMPLIANCY INFORMATION 55
Agency Identification Numbers 55 Approved antenna List 55 FCC / IC Requirements for Modular Approval 55 OEM Equipment Labeling Requirements 56 Antenna Requirements 56 Warnings required in OEM Manuals 56 Channel Warning 56
SERIAL INTERFACE 20
Interface Modes 20
Transparent Mode 20
API Mode 20 Serial Interface Baud Rate 21 Interface Timeout / RF Packet Size 22 Flow Control 22
RXD Data Buffer and CTS 23
TXD Data Buffer and RTS 23 Networking 24 Power Down Modes 26
Cyclic Sleep 26
Deep Sleep 26

ZB2430 TRANSCEIVER MODULE

AeroComm’s ZB2430 module is based on the IEEE 802.15.4 wireless communication standard and the robust ZigBee networking protocol and is one of the most powerful ZigBee compliant solutions on the market today. The ZB2430 provides OEMs with industry leading 2.4 GHz module performance in low power consumption, easy integration, long range, and superior features and functionality. Requiring no additional FCC licensing in the Americas, OEMs can easily make existing systems wireless with little or no RF expertise.
1

ZB2430 FEATURES

• Mesh architecture
• Energy harvester compatible
• Retries and Acknowledgements
• Programmable Network Parameters
•Multiple generic I/O
• 250 kbps RF data stream
• Software selectable interface baud rates from 110 bps to 115.2 kbps
• Non-standard baud rates supported
• Low cost, low power and small size ideal for high volume, portable and battery powered applications
• All modules are qualified for Industrial temperatures (-40°C to 80°C)
• Advanced configuration available using AT commands
• Easy to use Configuration & Test Utility software

OVERVIEW

The ZB2430 is a member of AeroComm's FlexRF OEM transceiver family. The ZB2430 is a cost effective, high performance, Direct Sequence Spread Spectrum (DSSS) transceiver; designed for integration into OEM systems operating under FCC part 15.247 regulations for the 2.4 GHz ISM band.
To boost data integrity and security, the ZB2430 uses DSSS technology featuring optional Advanced-Encryption Standards (AES) Communications include both system and configuration data via an asynchronous serial interface for OEM Host communications. All association and RF system data transmission/reception is performed by the transceiver.
This document contains information about the hardware and software interface between an AeroComm ZB2430 transceiver and an OEM Host. Information includes the theory of operation, specifications, interface definitions, configuration information and mechanical drawings.
Note: Unless mentioned specifically by name, the ZB2430 modules will be referred to as "radio" or "transceiver". Individual naming is used to differentiate product specific features. The host (PC/Microcontroller/Any device to which the ZB2430 module is connected) will be referred to as "OEM Host" or “Host.”
1.Feature not available at the time of this release.
1
. Fully transparent, these transceivers operate seamlessly in serial cable replacement applications.
www.aerocomm.com

SPECIFICATIONS

Table 1: ZB2430 Specifications
General
Interface Connector SMT or Pluggable
Antenna Chip antenna (p/n Laird MAF95029) or U.FL connector
Serial Interface Data Rate Baud rates from 110 bps to 115,200 bps. Non-standard baud rates are also supported.
Channels ZB2430-D: 15 Direct Sequence Channels
Security Channelization, Network Identification and optional 128-bit AES encryption
Frequency Band 2400 - 2483.5 MHz
Channel Bandwidth 3 MHz
Channel Spacing 5 MHz
RF Data Rate (Raw) 250 kbps
Max Throughput 64kbps
ZB2430-Q: 15 Direct Sequence Channels
1
Transceiver
2
RF Technology Direct Sequence Spread Spectrum
Modulation 0-QPSK
Output Power EIRP (2dBi gain antenna) ZB2430-D: -12 dBm to +5 dBm
Supply Voltage 3.0 - 3.5V, ±50mV ripple
Current Draw (mA)
Note: Power down modes are not Coordinator & Router devices.
Sensitivity (1% PER) ZB2430-D:-90 dBm typical
Range, Line of Site (based on 2dBi gain antenna) ZB2430-D: Up to 440 ft.
Temperature (Operating) -40°C to 85°C
Temperature (Storage) -50°C to +85°C
Dimensions 1.0” x 1.35” x 0.22” (25.4 x 34.3 x 5.5 mm)
supported on
ZB2430-Q : +2 dBm to +20 dBm
ZB2430-D: 25 mA 27 mA 0.5 uA 0.5 uA ZB2430-Q: 140 mA 44 mA 7.6 uA 7.6 uA
ZB2430-Q:-100 dBm typical
ZB2430-Q: Up to 440 ft. at +2 dBm / Up to 3.5 miles at +20 dBm
100% TX 100% RX Cyclic Sleep Deep Sleep
Environmental
Physical
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ZB2430 User’s Manual - v1.6
Table 1: ZB2430 Specifications
Certifications
SPECIFICATIONS
3
FCC Part 15.247 ZB2430-D: KQL-ZB2430D
Industry Canada (IC) ZB2430-D: 2268C-ZB2430D
CE ZB2430-D:Approved
1. Feature not available at the time of this release.
ZB2430-Q:KQL-ZB2430-100
ZB2430-Q:2268C-ZB2430
ZB2430-Q:Pending
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SPECIFICATIONS
4

PIN DEFINITIONS

The ZB2430 has a simple interface that allows OEM Host communications with the transceiver. Table 2 below shows the connector pin numbers and associated functions.
Table 2: Pin Definitions for the ZB2430 transceiver
SMT Pin
1 4 O GIO_0 Generic Output Pin
2 6 O GIO_1 Generic Output Pin
3 8 Do not Connect Has internal connection, for Aerocomm use only.
4 7 I GI0_2/ DE-RE Generic Input pin
5 19 I GIO_3 / AD_0 Has Internal connection. Reserved for future GPIO.
6 3 I RXD Asynchronous serial data input to transceiver
7 2 O TXD Asynchronous serial data output from transceiver
8 10 GND GND Signal Ground
9 1 PWR VCC 3.0 - 3.5 V ±50mV ripple (must be connected)
10 - PWR VPA 3.0 - 3.5 V ±50mV ripple (must be connected)
11 - GND GND Signal Ground
12 9 I Test / Sleep Int. Test Mode – When pulled logic Low and then applying power or resetting, the
Pluggable
Pin
Type Signal Name Function
transceiver’s serial interface is forced to a 9600, 8-N-1 rate. To exit Test mode, the transceiver must be reset or power-cycled with Test Mode pulled logic High or disconnected
Note: Because this mode disables some modes of operation, it should not be permanently pulled Low during normal operation.
Sleep mode interrupt - When logic Low, forces End Device to wake up from sleep mode. When logic High, allows End Device to sleep and wake-up according to specified poll rate. Sleep mode interrupt function available on End Devices only.
1
13 18 I/O GIO_4 / AD_1 Has Internal connection. Reserved for future GPIO.
14 5 I UP_Reset RESET – Controlled by the ZB2430 for power-on reset if left unconnected.
15 11 I CMD/Data When logic Low, the transceiver interprets OEM Host data as command data.
16 20 O In Range When logic Low, the transceiver is associated with a parent and has been
17 16 I RTS Request to Send – When enabled in EEPROM, the OEM Host can take this
After a stable power-on reset, a logic Low pulse will reset the transceiver.
When logic High or floating, the transceiver interprets OEM Host data as trans­mit data.
assigned a 16-bit Network Address. The Coordinator will report In Range after selecting a clear channel to operate.
High when it is not ready to accept data from the transceiver. NOTE: Keeping
High for too long can cause data loss due to buffer overflow.
RTS
2
ZB2430 User’s Manual - v1.6
Table 2: Pin Definitions for the ZB2430 transceiver
SPECIFICATIONS
5
SMT Pin
18 12 O CTS Clear to Send - Active Low when the transceiver is ready to accept data for
19 14 I/O GIO_8 / AD_5 Has Internal connection. Reserved for future GPIO.
20 13 O Sleep Ind. Sleep mode indicator. When logic Low, transceiver is in sleep mode. When
21 17 I/O GIO_6 / AD_3 Has Internal connection. Reserved for future GPIO.
22 15 I GIO_7 / AD_4 Has Internal connection. Reserved for future GPIO.
1. May be left disconnected on ZB2430-D devices.
2. Feature not implemented at time of release.
Pluggable
Pin
Type Signal Name Function
transmission. High when input buffer is filling. Contining to send data when CTS is high can cause buffer overflow and the loss of data.
logic High, transceiver is awake.
ENGINEER’S TIP
Design Notes:
• All I/O is 3.3V TTL.
• All inputs are weakly pulled High (20k) and may be left floating during normal operation. When implemented, RTS
• Minimum Connections: VCC, VPA, GND, TXD, & RXD.
• Signal direction is with respect to the transceiver.
• Unused pins should be left disconnected.
will be weakly pulled Low.
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HARDWARE INTERFACE

3

PIN DEFINITIONS

Generic I/O

Both GIn and GOn pins serve as generic input/output pins. Reading and writing of these pins can be performed on­the-fly using CC Commands.

RXD and TXD

The ZB2430 accepts 3.3 VDC TTL level asynchronous serial data from the OEM Host via the RXD pin. Data is sent from the transceiver, at 3.3V levels, to the OEM Host via the TXD pin.

Test/Sleep Int.

Test Mode - When pulled logic Low before applying power or resetting, the transceiver's serial interface is forced to 9600, 8-N-1 (8 data bits, No parity, 1 stop bit): regardless of actual EEPROM setting. The interface timeout is also set to 3 ms and the RF packet size is set to the default size of 0x54 (84 bytes). To exit, the transceiver must be reset or power-cycled with Test
Note: Because this pin disables some modes of operation, it should not operation.
pin logic High or disconnected.
be permanently pulled Low during normal
Sleep Mode Interrupt - When logic Low, forces End Device to wake up from sleep mode. When logic High, allows End Device to sleep and wake-up according to specified poll rate. Sleep Mode interrupt function available on End Devices only.

UP_Reset

UP_Reset provides a direct connection to the reset pin on the ZB2430 microprocessor and is used to force a soft reset. For a valid reset, reset must be asserted Low for an absolute minimum of 250 ns.

Command/Data

When logic High, the transceiver interprets incoming serial data as transmit data to be sent to other transceivers. When logic Low, the transceiver interprets incoming serial data as command data. When logic Low, data packets from the radio will not be transmitted over the RF interface however incoming packets from other radios will still be received.

In Range

The In Range pin will be driven low when the radio is associated with a network. In Range will always be driven low on a Coordinator.

RTS Handshaking*

With RTS mode disabled, the transceiver will send any received data to the OEM Host as soon as it is received. However, some OEM Hosts are not able to accept data from the transceiver all of the time. With RTS enabled, the OEM Host can prevent the transceiver from sending it data by de-asserting RTS (Low), the transceiver will send packets to the OEM Host as they are received.
(High). Once RTS is re-asserted
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ZB2430 User’s Manual - v1.6
Note: Leaving RTS de-asserted for too long can cause data loss once the transceiver's receive buffer reaches capacity.
*Feature not implemented at time of release.
HARDWARE INTERFACE

CTS Handshaking

If the transceiver buffer fills up and more bytes are sent to it before the buffer can be emptied, data loss will occur. The transceiver prevents this loss by deasserting CTS High as the buffer fills up and asserting CTS Low as the buffer is emptied. CTS High.
should be monitored by the Host device and data flow to the radio should be stopped when CTS is

Sleep Ind.

Sleep Indicator output. Sleep Ind. can be used to determine whether or not the transceiver is sleeping. When logic Low, the transceiver is in sleep mode. When logic High, the transceiver is awake.

AD In

AD In can be used as a cost savings to replace Analog-to-Digital converter hardware with the onboard 12-bit ADC.
Reading of this pin can be performed locally using the Read ADC command found in the On-the-Fly Control
Command Reference.
7
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TERMS & DEFINITIONS

Ad-Hoc Network: A wireless network composed of communicating devices without preexisting infrastructure. Typically created in a spontaneous manner and is self-organizing and self-maintaining.
Broadcast: Broadcast packets are sent to multiple radios. The ZB2430 allows several different broadcast types including broadcast to all devices & broadcast to Coordinator & all Routers.
Broadcast jitter: The random delay which is automatically introduced by a device before relaying a broadcast packet to prevent packet collisions.
Channel: The frequency selected for data communications within the PAN. The channel is selected by the Network Coordinator on power-up.
Channel Mask: The Channel Mask is a 32-bit field which specifies the range of allowable channels that the radio has to select from when choosing an RF channel. Valid only when Channel Select mode is enabled in EEPROM.
4
Clear Channel Assessment: An evaluation of the communication channel prior to a transmission to determine if the channel is currently occupied.
Energy Scan: A sweep of the entire frequency band which reports noise readings on every channel & is also capable of detecting Coordinators and reporting their Channel location.
FFD: Full Function Device. The Network Coordinator & Routers are examples of FFD’s.
IEEE 802.15.4: IEEE standard for Low-Power Wireless Personal Area Networks (WPAN’s). Specifies the physical interface between ZigBee devices.
MAC Address: A unique 64-bit address assigned to each radio. This address cannot be modified and never changes. It is used by the network to identify the device when assigning 16-bit Network Addresses.
Maximum Network Depth: The maximum number or Routers (hops) that a device can be away from the Coordinator. The current profile limit is 5.
Maximum Number of Routers: The total number of children that can serve as Routers for a Network device. The current profile limit is 6.
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ZB2430 User’s Manual - v1.6
TERMS & DEFINITIONS
Maximum Number of Children: The total number of children that can be associated with a single Network device. The current profile limit is 20; comprising of up to 6 Routers and 14 End Devices.
Mesh Network: An interconnection of nodes where nodes are permitted to transmit data directly to any other node.
Neighbor Table: A table used by the Coordinator and Router(s) to keep track of other devices operating in the same coverage area.
Network Address: The unique 16-bit address assigned to a device upon joining a PAN. This address is used for routing messages between devices and can be different each time a device is powered on. The Network Coordinator will always
have a Network Address of 0x0000. Note that addresses are not assigned in numerical order.
Operating Channel: The specific frequency selected for data communications. The operating channel is determined by the Coordinator on power-up.
Orphan Device: A device which has lost communication contact with or information about its Parent device.
9
PAN: Personal Area Network. Includes a Network Coordinator and one or more Routers/End Devices. The Network formation is determined by the Maximum Network Depth, Maximum Number of Routers, and Maximum Number of Children.
PAN ID: Similar to a Network ID. Devices which are operating with different PAN ID’s will not be associated to the same network.
Parent/Child: When a device joins the Network, it becomes a child of the device with which it is associated. Similarly, the device with which it associated becomes its parent device. Network devices can have multiple children, but only one parent. End Devices cannot be parents and are always children of the Coordinator or a Router. The Coordinator does not have a parent device.
POS: Personal Operating Space. The area within reception range of a specific device.
Profile: A collection of device descriptions, which together form a coorperative application. Devices utilizing different profiles will only support very basic inter-communications. The ZB2430 uses a private profile as specified by Aerocomm.
RFD: Reduced Function Device. The End Device is an example of an RFD.
Route Discovery: An operation using RREQ and RREP’s in which a ZigBee Coordinator or Router discovers a route to a device outside its POS.
Route Reply (RREP): A ZigBee command used to reply to a Route Request command.
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TERMS & DEFINITIONS
10
Route Request (RREQ): A ZigBee command used to discover paths through the network over which messages may be relayed.
Routing Table: A table in which the Coordinator or Router(s) store information required to participate in the routing of data packets throughout the network. The entire route is not stored, only the first step in the route.
Star Network: A network employing a single, central device through which all communication between devices must pass.
TX Cost: A counter of transmission successes/failures. TX Cost starts at 0x00, increments by one every time a packet fails to be delivered, and decrements by one every time a packet is successfully delivered. TX Cost has a range between 0x00 and 0x04.
Unicast: Unicast packets contain a destination address and are received by a single radio only. Unicast packets are point-to-point and do not include Broadcast packets.
ZigBee Stack: A Network specification based on the IEEE 802.15.4 Standard for Wireless Personal Area Networks (WPANs). The ZB2430 uses the Z-Stack (designed by TI) v.1.4.2 and complies to the ZigBee 2006 specification.
ZigBee Alliance: An association of companies working together to create a low-cost, low power consumption, two­way wireless communications standard (http://www.zigbee.org).

THEORY OF OPERATION

5

IEEE 802.15.4 & ZIGBEE OVERVIEW

The ZB2430 uses the ZigBee protocol stack, a network layer protocol which uses small, low power digital transceivers based on the IEEE 802.15.4 hardware standard. The 802.15.4 standard is a specification for a cost-effective, low data rate (<250 kbps), 2.4 GHz or 868/928 MHz wireless technology designed for personal-area and device-to-device wireless networking.
The IEEE 802.15.4 standard specifies the hardware requirements, including frequency bands, receiver sensitivity, modulation and spreading requirements. The ZigBee layer is the software layer that sits atop the 802.15.4 PHY/MAC layer and performs all packet routing and mesh networking.
There are three device types present in a ZigBee network: Coordinator (Full Function Device), Router (Full Function Device), and End Device (Reduced Function Device). Each network consists of a single Coordinator, optional Router(s), and optional Reduced Function End Device(s).
Coordinator
The Coordinator is responsible for establishing the operating channel and PAN ID for the entire Network. Once the Coordinator has established a Network, it allows Routers and End Devices to join the Network; assigning each device a unique 16-bit Network Address.
The Coordinator is intended to be mains powered (always on).
Router
Routers are responsible for creating and maintaining Network information and determining the optimal route for a data packet. Routers must first associate with the Network before other devices can join through them.
Routers are intended to be mains powered (always on).
• One Coordinator per Network
• Establishes Channel and PAN ID
• Responsible for Network formation and maintenance
• Full Function Device
• Packet routing capabilities
• Mains powered (always on)
• Power down modes are not supported
• Network address of 0x0000
• Multiple Routers can be used
• Allows other Routers/End Devices to join the Network
• Full Function Device
• Packet routing capabilities
• Mains powered (always on)
• Power down modes are not supported
• Unique netowork address dynamically assigned by parent
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THEORY OF OPERATION
12
End Device
While Coordinators and Routers can communicate with any device type, End Devices can communicate only through their parent device. Ideally the End Devices will be in sleep mode all the time. When they have data to send, they wake up, send the data and then go back to sleep. The Parent (Coordinator/Router) of an End Device should be mains powered to allow it to store data to be sent to the sleeping End Device.
• Multiple End Devices can be used
• No packet routing capabilities
• Can communicate with other devices in the Network through its Parent Device
• Reduced Function Device
• Mains or battery powered
• Power down modes are supported
• Unique network address dynamically asssigned by parent

CREATING A NETWORK

The IEEE 802.15.4 MAC provides support for two wireless network topologies: star and mesh. The management of these networks is performed by the ZigBee layer. All devices, regardless of topology, participate in the network using their unique 16-bit address assigned by the Coordinator.

Mesh

The mesh topology allows any Full Function Device (Coordinator or Router) to communicate directly with any other device within its range and to have messages relayed to devices which are out of range via multi-hop routing of messages. While a FFD device can communicate with a Reduced Function Device (RFD), RFD’s cannot directly route messages and must have their messages routed by their parent device (Coordinator or Router). ZigBee mesh enables the formation of more complex networks, including ad-hoc, self-organizing, and self-healing structures.
Figure 1 shows a typical ZigBee network architecture.
ZB2430 User’s Manual - v1.6
Figure 1: ZigBee Network Topologies
THEORY OF OPERATION
13

PARENT/CHILD RELATIONSHIP

ZigBee uses a parent/child relationship between network devices. The network begins with the Coordinator as the first device on the network. When a new device (Router or End Device) associates with the Coordinator, it becomes a child of the Coordinator and similarly, the Coordinator becomes a parent of that device. If a second device joins the network, the Coordinator will once again become the parent and the device will become a child of the Coordinator. If a device is not in range of the Coordinator, it subsequently joins the network through a Router, and becomes a child of that Router. Network devices can have multiple children, but only one parent. By design, End Devices cannot be parents and are always
children of the Coordinator or a Router.
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THEORY OF OPERATION
14
Figure 2: Parent/Child Relationship

NETWORK LIMITATIONS

The ZigBee network structure and ultimate size are specified by Stack profiles. The Stack profiles define the maximum number of Layers, maximum number of Children per Parent, & maximum number of Routers that can be Children. These parameters are set during code compilation and cannot be altered after compilation. The ZB2430 uses the restricitions specified by the Home Lighting & Controls profile.
The ZigBee Coordinator determines the maximum number of children any device within its network is allowed. Of these children, a maximum number can be router-capable devices; while the remainder shall be reserved for end devices. Each device has an associated depth which indicates the minimum number of hops a transmitted packet must travel to reach the ZigBee Coordinator (see Figure 3: "Network Depth" on page 15).

Maximum Network Depth

The Coordinator has a depth of zero and its Children have a depth of 1. Maximum Network Depth specifies the maximum number of hops (Routers) that a node can be away from the Coordinator. The Home Lighting & Controls profile limits the maximum network depth to 5.
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