User's Guide
Table Of Contents
- XBee/XBee-PRO S2C 802.15.4 RF Module User Guide
- Technical specifications
- Hardware
- Configure the XBee/XBee-PRO S2C 802.15.4 RF Module
- Modes
- Operation
- AT commands
- Special commands
- Networking and security commands
- C8 (802.15.4 Compatibility)
- CH (Operating Channel)
- ID (Network ID)
- DH (Destination Address High)
- DL (Destination Address Low)
- MY (Source Address)
- SH (Serial Number High)
- SL (Serial Number Low)
- MM (MAC Mode)
- RR (XBee Retries)
- RN (Random Delay Slots)
- ND (Network Discovery)
- NT (Node Discover Timeout)
- NO (Node Discovery Options)
- DN (Discover Node)
- CE (Coordinator Enable)
- SC (Scan Channels)
- SD (Scan Duration)
- A1 (End Device Association)
- A2 (Coordinator Association)
- AI (Association Indication)
- DA (Force Disassociation)
- FP (Force Poll)
- AS (Active Scan)
- ED (Energy Detect)
- EE (Encryption Enable)
- KY (AES Encryption Key)
- NI (Node Identifier)
- NP (Maximum Packet Payload Bytes)
- RF interfacing commands
- Sleep commands
- Serial interfacing commands
- I/O settings commands
- D0 (DIO0/AD0)
- D1 (DIO1/AD1)
- D2 (DIO2/AD2)
- D3 (DIO3/AD3)
- D4 (DIO4)
- D5 (DIO5/ASSOCIATED_INDICATOR)
- D8 (DIO8/SLEEP_REQUEST)
- P0 (RSSI/PWM0 Configuration)
- P1 (PWM1 Configuration)
- P2 (SPI_MISO)
- M0 (PWM0 Duty Cycle)
- M1 (PWM1 Duty Cycle)
- P5 (SPI_MISO)
- P6 (SPI_MOSI Configuration)
- P7 (SPI_SSEL )
- P8 (SPI_SCLK)
- P9 (SPI_ATTN)
- PR (Pull-up/Down Resistor Enable)
- PD (Pull Up/Down Direction)
- IU (I/O Output Enable)
- IT (Samples before TX)
- IS (Force Sample)
- IO (Digital Output Level)
- IC (DIO Change Detect)
- IR (Sample Rate)
- RP (RSSI PWM Timer)
- I/O line passing commands
- Diagnostic commands
- Command mode options
- Operate in API mode
- API mode overview
- API frame specifications
- Escaped characters in API frames
- Frame descriptions
- TX Request: 64-bit address frame - 0x00
- TX Request: 16-bit address - 0x01
- AT Command frame - 0x08
- AT Command - Queue Parameter Value frame - 0x09
- Remote AT Command Request frame - 0x17
- RX Packet: 64-bit Address frame - 0x80
- Receive Packet: 16-bit address frame - 0x81
- RX (Receive) Packet: 64-bit address IO frame- 0x82
- RX Packet: 16-bit address I/O frame - 0x83
- AT Command Response frame - 0x88
- TX Status frame - 0x89
- Modem Status frame - 0x8A
- Remote Command Response frame - 0x97
- Regulatory information
- Load 802.15.4 firmware on ZB devices
- Migrate from XBee through-hole to surface-mount devices
- PCB design and manufacturing
Operation Node discovery
XBee/XBee-PRO S2C 802.15.4 RF Module User Guide
63
Indirect transmissions can only occur on a Coordinator. Thus, if all nodes in a network are End Devices,
only direct transmissions occurs. Indirect transmissions are useful to ensure packet delivery to a
sleeping node. The Coordinator currently is able to retain up to five indirect messages.
Direct transmission
A Coordinator can be configured to use only direct transmission by setting the SP (Cyclic Sleep Period)
parameter to 0. Also, a Coordinator using indirect transmissions reverts to direct transmission if it
knows the destination device is awake.
To enable this behavior, the ST (Time before Sleep) value of the Coordinator must be set to match the
ST value of the End Device. Once the End Device either transmits data to the Coordinator or polls the
Coordinator for data, the Coordinator uses direct transmission for all subsequent data transmissions
to that device address until ST time occurs with no activity (at which point it reverts to using indirect
transmissions for that device address). "No activity" means no transmission or reception of messages
with a specific address. Broadcast messages do not reset the ST timer.
Indirect transmission
To configure Indirect Transmissions in a Personal Area Network (PAN), the SP (Cyclic Sleep Period)
parameter value on the Coordinator must be set to match the longest sleep value of any End Device.
The sleep period value on the Coordinator determines how long (time or number of beacons) the
Coordinator retains an indirect message before discarding it.
An End Device must poll the Coordinator once it wakes from Sleep to determine if the Coordinator has
an indirect message for it. For Cyclic Sleep Modes, this is done automatically every time the device
wakes (after SP time). For Pin Sleep Modes, the A1 (End Device Association) parameter value must be
set to enable Coordinator polling on pin wake-up (set in bit 3). Alternatively, an End Device can use the
FP (Force Poll) command to poll the Coordinator as needed.
Acknowledgment
If the transmission is not a broadcast message, the device expects to receive an acknowledgment
from the destination node. If an acknowledgment is not received, the packet is resent up to three
more times. If the acknowledgment is not received after all transmissions, an ACK failure is recorded.
Node discovery
Node discovery has three variations as shown in the following table:
Commands Syntax Description
Node Discovery
ND
Seeks to discover all nodes in the network (on the current PAN
ID).
Directed Node
Discovery
ND <NI
String>
Seeks to discover if a particular node named <NI String> is found
in the network.
Destination Node
DN
<NI
String>
Sets DH/DL to point to the MAC address of the node whose <NI
String> matches.
Node discovery
The node discovery command (without an NI string designated) sends out a broadcast to every node
in the PAN ID. Each node in the PAN sends a response back to the requesting node.