Digi XBPSX, XBSX User Manual
XBee/XBee-PRO XTC
Radio Frequency (RF) Module
User Guide
Revision history
900001476 A
Revision Date Description
A December, 2015 Baseline release of the document.
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Digi, Digi International, and the Digi logo are trademarks or registered trademarks in the United States
and other countries worldwide. All other trademarks mentioned in this document are the property of their
respective owners.
© 2015 Digi International Inc. All rights reserved.
Disclaimers
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.
Warranty
To view the product's warranty information, go to the following website:
http://www.digi.com/howtobuy/terms
Customer support
Telephone (8:00 am — 5:00 pm U.S. Central Time):
Toll-free US and Canada: 866.912.3444
Worldwide: +1 952.912.3456
Online: www.digi.com/support/eservice
Mail:
Digi International Inc.
11001 Bren Road East
Minnetonka, MN 55434
USA
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 2
Contents
Revision history 2
The XBee/XBee-PRO XTend Compatible (XTC) RF module
About the XTCRF module 9
Applicable firmware 9
Technical specifications 10
Performance specifications 10
Power requirements 11
Networking and security specifications 11
Physical specifications 12
Regulatory approvals 12
Hardware
Mechanical drawings 14
Pin signals 16
Recommended pin connections 18
XTC RF Module Modes
Transparent and API operating modes 19
Transparent operating mode 19
API operating mode 19
Additional modes 20
Command mode 20
Binary Command mode 20
Idle mode 20
Receive mode 20
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 3
Sleep modes 21
Shutdown mode 21
Transmit mode 21
Enter Command mode 21
Send AT commands 22
Exit Command mode 22
Enter Binary Command mode 23
Exit Binary Command mode 23
Binary Command mode FAQs 23
Sleep modes 25
Pin Sleep (SM = 1) 26
Serial Port Sleep (SM = 2) 27
Cyclic Sleep Mode (SM = 4-8) 27
Operation
Serial interface 29
UART data flow 29
Serial data 29
Flow control 30
Data In (DIN) buffer and flow control 30
Data Out (DO) buffer and flow control 31
Configure the XTC RF Module
Configure the device using XCTU 33
Program the XTC RF Module
XTC RF Module programming examples 34
Connect the device to a PC 34
Modify a device address 35
Restore device defaults 35
Send binary commands 35
Query binary commands 36
XTC RF Module commands
Command mode options 41
AT (Guard Time After) 41
BT (Guard Time Before) 41
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 4
CC (Command Sequence Character) 42
CF (Number Base) 42
CN (Exit Command Mode) 43
CT (Command Mode Timeout) 44
E0 (Echo Off) 44
E1 (Echo On) 45
Diagnostic commands 45
%V (Board Voltage) 45
DB (Received Signal Strength) 46
GD (Receive Good Count) 47
HV (Hardware Version) 48
RC (Ambient Power - Single Channel) 48
RE (Restore Defaults) 49
RM (Ambient Power) 50
RP (RSSI PWM Timer) 51
SH (Serial Number High) 52
SL (Serial Number Low) 52
TP (Board Temperature) 53
TR (Transmit Error Count) 53
VL (Firmware Version - Verbose) 54
VR (Firmware Version - Short) 54
WA (Active Warning Numbers) 55
WN (Warning Data) 56
WS (Sticky Warning Numbers) 58
MAC/PHY commands 58
AM (Auto-set MY) 58
DT (Destination Address) 59
HP (Preamble ID) 60
ID (Network ID) 60
MK (Address Mask) 61
MT (Multi-transmit) 61
MY (Source Address) 62
RN (Delay Slots) 63
RR (Retries) 64
TT (Streaming Limit) 64
RF interfacing commands 65
BR (RF Data Rate) 65
FS (Forced Synch Time) 66
MD (RF Mode) 66
PB (Polling Begin Address) 67
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 5
PD (Minimum Polling Delay) 68
PE (Polling End Address) 68
PK (Maximum RF Packet Size) 69
PL (TX Power Level) 71
TX (Transmit Only) 72
Security commands 73
KY (AES Encryption Key) 73
Serial interfacing commands 73
AP (API Enable) 74
BD (Interface Data Rate) 74
CD (GP02 Configuration) 76
CS (GP01 Configuration) 77
FL (Software Flow Control) 78
FT (Flow Control Threshold) 79
NB (Parity) 79
RB (Packetization Threshold) 80
RO (Packetization Timeout) 81
RT (GPI1 Configuration) 82
SB (Stop Bits) 82
Sleep commands 83
FH (Force Wakeup Initializer) 83
HT (Time before Wake-up Initializer) 84
LH (Wakeup Initializer Timer) 84
PW (Pin Wakeup) 85
SM (Sleep Mode) 86
ST (Time before Sleep) 87
XTC RF ModuleSpecial commands 88
WR (Write) 88
XTC RF Module API operation
API mode overview 89
API frame specifications 89
Calculate and verify checksums 91
Escaped characters in API frames 92
XTC RF ModuleAPI frame overview 93
RF Module Status 0x8A 93
Transmit Request: 16-bit address 0x01 94
Transmit Status frame 0x89 96
Receive Packet: 16-bit address 0x81 97
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 6
Network configurations
network topologies 100
Point-to-point networks 100
Point-to-multipoint networks 101
Peer to peer networks 102
Addressing 103
Address recognition 103
Basic communications 104
Streaming mode (default) 104
Multi-transmit mode 105
Repeater mode 106
Polling mode (basic) 111
Acknowledged communications: Acknowledged mode 113
Acknowledged mode connection sequence 114
Polling mode (acknowledged) 115
Certifications
FCC (United States) 117
OEM labeling requirements 117
FCC notices 118
FCC antenna certifications 118
XBee-PRO XTC Antenna options 119
XBee XTC antenna options 127
Industry Canada (IC) 135
Labeling requirements 135
Transmitters for detachable antennas 136
Detachable antennas 136
ACMA (Australia) 137
Power requirements 137
PCB design and manufacturing
Recommended footprint and keepout 138
Design notes 140
Host board design 140
Improve antenna performance 141
RF pad version 141
Recommended solder reflow cycle 143
Flux and cleaning 144
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 7
Rework 144
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 8
The XBee/XBee-PRO XTend Compatible (XTC) RF module
About the XTCRF module
The XBee/XBee-PRO XTend Compatible (XTC) RF module provides a radio frequency (RF) solution for the
reliable delivery of critical data between remote devices. It is a 30 dBm (1 Watt) long-range original
equipment manufacturer (OEM) device. We also offer a low power version of this module that offers
transmit power adjustable up to 13 dBm.
The XTC module uses Frequency Hopping Spread Spectrum (FHSS) agility to avoid interference by hopping
to a new frequency on every packet transmission or re-transmission. Its transmit power is software
adjustable up to 30 dBm, which is the maximum output power allowable by governments that use 900
MHz as a license-free band. The XTC module is approved for use in the United States, Canada, Australia
and other countries.
The XTC transfers a standard asynchronous serial data stream, operates within the ISM 900 MHz
frequency band and offers two RF data rates of 10 kb/s and 125 kb/s.
As the name suggests, the XTC is over-the-air compatible with Digi's XTend module. The XTC is not a drop-
in replacement for the XTend. If you require form factor compatibility, you must use the XTend vB RF
Module.
For new applications, we recommend that you use the XBee/XBee-Pro SX module. It uses the same
hardware as the XTC but we optimize the firmware for the best range and interference immunity.
However, it is not over-the-air compatible with the XTend.
Applicable firmware
This manual supports the following firmware:
l 0x200X for XTC Hopping
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 9
Technical specifications
Technical specifications
The following tables provide the device's technical specifications.
When operating at 1 W power output, observe a minimum separation distance of 6 ft (2 m)
between devices. Transmitting in close proximity of other devices can damage the device's
front end.
Performance specifications
The following table provides the performance specifications for the device. They cover the standard (XBee-
PRO) and low-power (XBee) versions of the device.
Specification XBee XTC XBee-PRO XTC
Frequency range ISM 902 to 928 MHz
RF data rate (software selectable) 10 kb/s to 125 kb/s
Transmit power (software selectable) Up to 13 dBm Up to 30 dBm
1
Channels 10 hopping sequences share 50 frequencies
Available channel frequencies 50
Receiver sensitivity 10 kb/s -110 dBm
125 kb/s -100 dBm
Outdoor range (line of sight) 10 kb/s Up to 5 miles up to 40 miles
2
125 kb/s Up to 1.5 miles Up to 7 miles
Indoor range 10 kb/s Up to 360 feet (110 m) Up to 1,000 feet (300 m)
125 kb/s Up to 180 feet (55 m) Up to 500 feet (150 m)
1
30 dBm guaranteed at 3.3 V and above. Maximum transmit power will reduce at lower voltages. See PL (TX Power
Level) on page 71 for more information on adjustable power levels.
2
Estimated based on a 9 mile range test with dipole antennas.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 10
Technical specifications
Power requirements
The following table provides the power requirements for the device.
Specification XBee XTC XBee-PRO XTC
Supply voltage 2.4 to 3.6 VDC, 3.3 V typical 2.6 to 3.6 VDC, 3.3 V typical
Receive current VCC = 3.3 V 40 mA 40 mA
Transmit current VCC = 3.3 V 55 mA @ 13 dBm 900 mA @ 30 dBm
VCC = 3.3 V 45 mA @ 10 dBm 640 mA @ 27 dBm
VCC = 3.3 V 35 mA @ 0 dBm 330 mA @ 20 dBm
Sleep current 2.5 µA 2.5 µA
Networking and security specifications
The following table provides the networking and security requirements for the device.
Specification Value
Frequency 902-928 MHz, 915-928 MHz for the International variant
Spread spectrum Frequency Hopping Spread Spectrum (FHSS)
Modulation Frequency Shift Keying (FSK/GFSK)
Supported network
topologies
Peer-to-peer (master/slave relationship not required), point-to-point, and
point-to-multipoint
1
Channel capacity 10 hop sequences share 50 frequencies
1
We do not recommend the 20 dBm power level when operating at temperatures below 0°C. Output power may
vary significantly when operating below 0°C.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 11
Technical specifications
Specification Value
Encryption 256-bit or 128-bit AES depending on region, not software selectable
256-bit is only available on the North American variant
128-bit is only available on the Australian and international variants
The KY command enables and disables encryption. The KY command sets
the key
Physical specifications
The following table provides the physical specifications for the device.
Specification Value
Dimensions 1.33 x 0.87 x 0.12" (3.38 x 2.21 x 1.29 cm)
Weight 3 g
RoHS Compliant
Manufacturing ISO 9001:2000 registered standards
Connector 37 castellated SMT pads
Antenna connector options U.FL or RF pad
Antenna impedance 50 ohms unbalanced
Maximum input RF level at antenna port 6 dBm
Operating temperature -40°C to 85°C
Regulatory approvals
The following table provides the regulatory approvals for the device.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 12
Country XBee XTC XBee-PROXTC
United States FCC ID: MCQ-XBSX (pending) FCC ID: MCQ-XBPSX (pending)
Canada IC: 1846A-XBSX (pending) IC: 1846A-XBPSX (pending)
Australia RCM (pending) RCM (pending)
Technical specifications
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 13
Hardware
Mechanical drawings
The following images show the XTC mechanical drawings. The XTC has the same form factor as other Digi
surface mount (SMT) XBee devices, except there is an additional copper ground pad on the bottom.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 14
Mechanical drawings
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 15
Pin signals
Pin signals
The following table describes the pin signals. Low-asserted signals have a horizontal line over the signal
name.
Pin Designation I/O Function
1 GND - Ground
2 VCC I Power supply
3 DOUT O UART Data Out
4 DIN I UART Data In
5 GPO2/RX LED O General Purpose Output / RX LED
RESET
6
I Module reset
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 16
Pin Designation I/O Function
7 RSSI O RX Signal Strength Indicator
8 - Disabled
9 Reserved NC Do not connect
10 SLEEP (DTR) I Pin Sleep Control Line
11 GND - Ground
12 - Disabled
13 GND - Ground
Pin signals
14 - Disabled
15 - Disabled
16 - Disabled
17 - Disabled
18 Reserved NC Do not connect
19 Reserved NC Do not connect
20 Reserved NC Do not connect
21 Reserved NC Do not connect
22 GND - Ground
23 Reserved NC Do not connect
24 - Disabled
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 17
Pin Designation I/O Function
Pin signals
25 GPO1/CTS/RS-
485 TX_EN
26 ON/SLEEP O Module sleep status indicator
27 Reserved NC Do not connect
28 TX_PWR O Transmit power
29 RTS/CMD I Request-to-Send Flow Control / Binary Command Control
30 - Disabled
31 - Disabled
CONFIG
32
33 - Disabled
O General Purpose Output / Clear-to-Send Flow Control /
RS-485 Transmit Enable
I Configuration
34 Reserved NC
35 GND - Ground
36 RF I/O RF IO for RF pad variant
37 NC NC
38 GND - Ground pad for heat transfer to host PCB
Note If you integrate the XTC with a host PC board, leave all lines you do not use disconnected
(floating).
Recommended pin connections
The only required pin connections are VCC, GND, DOUT and DIN. To support serial firmware updates, you
should connect VCC, GND, DOUT, DIN, RTS, and SLEEP (DTR).
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 18
XTC RF Module Modes
Transparent and API operating modes
The firmware operates in several different modes. Two top-level modes establish how the device
communicates with other devices through its serial interface: Transparent operating mode and API
operating mode.
Transparent operating mode
Devices operate in this mode by default. We also call this mode “AT operating mode.” The device acts as a
serial line replacement when it is in Transparent operating mode. The device queues all UART data it
receives through the DIN pin for RF transmission. When a device receives RF data, it sends the data out
through the DOUT pin. You can set the configuration parameters using the AT Command interface.
API operating mode
API operating mode is an alternative to Transparent mode. API mode is a frame-based protocol that
allows you to direct data on a packet basis. It can be particularly useful in large networks where you need
to control the route a data packet takes or when you need to know which node a data packet is from. The
device communicates UART data in packets, also known as API frames. This mode allows for structured
communications with serial devices. It is helpful in managing larger networks and is more appropriate for
performing tasks such as collecting data from multiple locations or controlling multiple devices remotely.
There are two types of API operating modes: one with escaped characters and another without escaped
characters.
l Without escaped characters (AP = 1). This mode eliminates escaping character sequences.
This makes it simpler to create code and libraries, but runs a minor risk of lost frames or
errors due to the possibility that payload data can be confused with frame structure. We
do not recommend this mode for noisy radio environments and where payload data may
include special characters (specifically 0x7E, 0x7D, 0x11, and 0x13).
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 19
Additional modes
l With escaped characters (AP = 2). API escaped operating mode works similarly to API
mode. The only difference is that when working in API escaped mode, the software must
escape any payload bytes that match API frame specific data, such as the start-of-frame
byte (0x7E).
Additional modes
In addition to the serial communication modes, several modes apply to how to configure devices and how
devices communicate with each other.
Command mode
Command mode is a state in which the firmware interprets incoming characters as commands. Command
mode allows you to modify the device’s firmware using parameters you can set using AT commands. When
you want to read or set any setting of the device, you have to send it an AT command. Every AT command
starts with the letters "AT" followed by the two characters that identify the command the device issues
and then by some optional configuration values. For more details, see Enter Command mode on the next
page.
Binary Command mode
Binary Command mode allows you to configure a device at a faster rate than AT commands will allow.
Using binary commands to send and receive parameter values is the fastest way to change the operating
parameters of the device. Use binary commands to:
l Sample signal strength and/or error counts;
l Change device addresses and channels for polling systems when a quick response is
necessary.
For more details, see Enter Binary Command mode on page 23 and DB (Received Signal Strength) on page
46.
Idle mode
When not receiving or transmitting data, the device is in Idle mode. During Idle mode, the device listens for
valid data on the serial port.
Receive mode
If a destination node receives a valid RF packet, the destination node transfers the data to its serial
transmit buffer. For the serial interface to report receive data on the RF network, that data must meet
the following criteria:
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 20
Additional modes
l ID match
l Channel match
l Address match
Sleep modes
Sleep Modes enable the device to enter states of low-power consumption when not in use. The device
support three software sleep modes:
l Pin Sleep: the host controls this
l Serial Port Sleep: wakes when it detects serial port activity
l Cyclic Sleep: wakes when it detects RF activity
For more information, see Sleep modes on page 25.
Shutdown mode
Shutdown mode offers the lowest power mode available to the device. This is helpful for applications that
must keep power consumption to a minimum during idle periods.
When you drive the SHDN pin (pin 7) low, it forces the device into Shutdown mode. This halts any
communication in progress (transmit or receive) and any buffered data is lost. For any other mode of
operation, you must drive or pull SHDN high.
Immediately after the SHDN pin changes states from low to high, the device resets. After reset, the
application must observe a delay time of <100 ms.
While SHDN is driven low, the device sets the following pins to high impedance: DCD, TX_PWR, RX LED, DO
and CTS. The SHDN line is driven low during shutdown.
The following input pins may continue to be driven by external circuitry when in shutdown mode: RTS, DI
and SHDN.
Because the DO pin is set to high impedance during Shutdown, if the XTC RF Module is connected to a
processor, the UART receive pin could be floating. Place a weak pull-up between the device and the
microcontroller so that the application does not misinterpret noise as data.
Transmit mode
When the device receives serial data and is ready to packetize it, the device exits Idle mode and attempts
to transmit the serial data.
Enter Command mode
There are two ways to enter Command mode:
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 21
Additional modes
1. To get a device to switch into this mode, you must issue a unique string of text in a special
way: +++ (default). When the device sees a full second of silence in the data stream
followed by the string +++ (without Enter or Return) and another full second of silence, it
knows to stop sending data through and start accepting commands locally.
Do not press Return or Enter after typing +++ because it will interrupt the guard time
silence and prevent you from entering Command mode.
2. Assert (low) the CONFIG pin. Turn the power going to the device off and back on.
The device sends the letters OK followed by a carriage return out of the UART to indicate that it entered
Command mode.
You can customize the guard times and timeout in the device’s configuration settings. See CC (Command
Sequence Character) on page 42, BT (Guard Time Before) on page 41 and AT (Guard Time After) on page
41.
Send AT commands
Once the device enters Command mode, use the syntax in the following figure to send AT commands.
To read a parameter value stored in the device’s register, omit the parameter field.
The preceding example would enable software flow control.
To store the new value to non-volatile (long term) memory, send the WR (Write) command. This allows
parameter values that you modify to persist in the device's registry after a reset. Otherwise, the device
restores parameters to the previous values after a reset.
Respond to AT commands
When you send a command to the device, the device parses and runs the command. If the command runs
successfully, the device returns an OK message. If the command errors, the device returns an ERROR
message.
Exit Command mode
1. Send the CN (Exit Command Mode) command followed by a carriage return.
or:
2. If the device does not receive any valid AT commands within the time specified by CT
(Command Mode Timeout), it returns to Idle mode. The default Command Mode Timeout is
20 seconds.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 22
Additional modes
Enter Binary Command mode
To enter Binary Command mode, you must first be in Command mode:
1. Set RT to 1; see RT (GPI1 Configuration) on page 82.
2. Assert CMD by driving pin 1029 high to enter Binary Command mode.
3. Disable hardware flow control.
CTS (pin 25) is high when the firmware executes a command. That is why you must disable hardware flow
control, because CTS holds off parameter bytes.
Exit Binary Command mode
To exit Binary Command mode, de-assert CMD by driving pin 2910 low.
Binary Command mode FAQs
Since sending and receiving binary commands takes place through the same serial data path as live data,
interference between the two types of data can be a concern. Some common questions about using binary
commands are:
l What are the implications of asserting CMD while the device is sending or receiving live
data?
You must assert the CMD pin (pin 2910) in order to send binary commands to the device. You can assert
the CMD pin to recognize binary commands anytime during the transmission or reception of data.
The device only checks the status of the CMD signal at the end of the stop bit as the byte shifts into the
serial port.
The firmware does not allow control over when the device receives data, except by waiting for dead
time between bursts of communication.
If the command is sent in the middle of a stream of payload data, the device executes the command in
the order it is received. If the device is continuously receiving data, it waits for a break in the data it
receives before executing the command.
In the following figure, the host writes a value to a register and then reads it out of the device to verify
it. While not in the middle of other received data, the CTS signal outlines the data response out of the
device.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 23
Additional modes
Signal number Pin name
1 DIN (Pin 4)
2 DOUT (Pin 3)
3 CTS (Pin 259)
4 CMD (Pin 2910)
l After sending serial data, is there a minimum time delay before you can assert CMD?
l Is a time delay required after CMD is de-asserted before payload data can be sent?
The host must observe a minimum time delay of 100 µs after sending the stop bit of the command byte
before the host de-asserts the CMD pin. The command executes after the host sends all of its
associated parameters. If the device does not receive all of these parameters within 0.5 seconds, the
device returns to Idle mode.
Note When a host sends parameters, they are two bytes long with the least significant byte sent first.
Binary commands that return one parameter byte must be written with two parameter bytes.
Example: to set PL to 3, send the following data: 0x3A 0x03 0x00 (Binary Command, LSB, MSB).
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 24
Sleep modes
l How does one discern between live data and data received in response to a command?
To query command parameters using Binary Command mode, set the most significant bit of the binary
command. This can be accomplished by logically ORing (bit-wise) the binary command with
hexadecimal 0x80. The parameter bytes are returned in hexadecimal bytes with the least significant
bit first (if multiple bytes are returned).
Example: to query HP in Binary Command mode, instead of setting it, send 0x11 (HP binary command)
as 0x91 with no parameter bytes.
The device must be in Binary Command mode in order for the device to recognize a binary command;
see Enter Binary Command mode on page 23.
If the device is not in Binary Command mode (the RT parameter value is not 1), the device does not
recognize that the CMD pin is asserted and therefore does not recognize the data as binary
commands.
For an example of binary programming, see Send binary commands on page 35.
Sleep modes
For the device to enter one of the sleep modes, SM must have a non-zero parameter value, and it must
meet one of the following conditions:
1. The device is idle (no data transmission or reception) for the amount of time defined by
the ST parameter. ST is only active when SM = 4-5.
2. The host asserts SLEEP (pin 10). This only applies to the Pin Sleep option.
When in Sleep mode, the device does not transmit or receive data until it transitions to Idle mode.
Use the SM command to enable or disable all Sleep modes. The following table shows the transitions into
and out of Sleep modes.
Sleep
mode
(setting)
Pin Sleep
(SM = 1)
Transition into
Sleep mode
Assert (high) SLEEP pin. A
microcontroller can shut
down and wake devices via
the SLEEP pin.
The device completes a
transmission or reception
before activating Pin Sleep.
Transition out of Sleep
mode (wake)
Related
commands
De-assert (low) SLEEP pin SM
Power
consumption
< 147 µA
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 25
Sleep modes
Sleep
mode
(setting)
Serial
Port
Sleep
(SM = 2)
Cyclic
Sleep
(SM = 4 -
8)
Transition into
Sleep mode
Automatic transition to Sleep
Mode occurs after a user-
Transition out of Sleep
mode (wake)
When a serial byte is
received on the DI pin
defined period of inactivity
(no transmitting or receiving
of data).
Period of inactivity is defined
by the ST command.
The device transitions in and out of Sleep Mode in cycles
(you set the sleep interval of time using the SM command).
The cyclic sleep interval of time must be shorter than the
interval of time that is defined by the LH command.
You can for the device into Idle Mode using the SLEEP pin if
you issue the PW command.
Related
commands
Power
consumption
(SM), ST 7.3 mA
(SM), ST,
HT, LH, PW
See Power
requirements
The SM (Sleep Mode) command is central to setting all Sleep Mode configurations. By default, Sleep Modes
are disabled (SM = 0) and the device remains in Idle/Receive Mode. When in this state, the device remains
constantly ready to respond to serial or RF activity.
Pin Sleep (SM = 1)
l Pin/Host-controlled
l Typical sleep current: 2.5 µA
When the host asserts the SLEEP pin, the device finishes any transmitting or receiving activity, enters Idle
mode, then enters a sleep state. When in Pin Sleep mode, the device does not respond to serial or RF
activity.
After enabling Pin Sleep, the SLEEP pin controls whether the device is active or sleeping. When the host de-
asserts SLEEP, the device is fully operational. When the host asserts SLEEP, the device transitions to Sleep
mode and remains in its lowest power-consuming state until the host de-asserts the pin. This pin is only
active if the device is setup to operate in this mode; otherwise the firmware ignores the pin.
Once in Pin Sleep, the device de-asserts (high) CTS (pin 259) , indicating that other devices should not send
data to the device. The device also de-asserts (low) the TX_PWR line (pin 284) when the device is in Pin
Sleep mode.
Note The device completes a transmission or reception before activating Pin Sleep.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 26
Sleep modes
Serial Port Sleep (SM = 2)
l Wake on serial port activity
l Typical sleep current: 6.3 mA
Serial Port Sleep is a Sleep mode in which the device runs in a low power state until it detects serial data
on the DI pin.
The ST command determines the period of time that the device sleeps. Once it receives a character
through the DI pin, the device returns to Idle mode and is fully operational.
Cyclic Sleep Mode (SM = 4-8)
l Typical sleep Current: 2.5 µA (when asleep)
Cyclic Sleep modes allow device wakes according to the times designated by the cyclic sleep settings. If
the device detects a wake-up initializer during the time it is awake, the device synchronizes with the
transmitting device and receives data after the wake-up initializer runs its duration. Otherwise, the device
returns to Sleep mode and continues to cycle in and out of activity until a wake-up initializer is detected.
While the device is in Cyclic Sleep mode, it de-asserts (high) CTS (pin 259) to indicate not to send data to
the device. When the device awakens to listen for data, it asserts CTS and transmits any data received on
the DI pin. The device also de-asserts (low) the TX_PWR (pin 284) when it is in Cyclic Sleep mode.
The device remains in Sleep mode for a user-defined period of time ranging from 1 second to 16 seconds
(SM parameters 4 through 8). After this interval of time, the device returns to Idle mode and listens for a
valid data packet. The listen time depends on the BR parameter setting. The default BR setting of 1
requires at least a 35 ms wake time, while the BR setting of 0 requires a wake time of up to 225 ms. If the
device does not detect valid data on any frequency, it returns to Sleep mode. If it detects valid data, it
transitions into Receive mode and receives the incoming RF packets. The device then returns to Sleep
mode after a period of inactivity determined by the ST parameter.
You can also configure the device to wake from cyclic sleep when the SLEEP pin is de-asserted. To
configure a device to operate in this manner, you must issue the PW (Pin Wake-up) command. When you
de-assert the SLEEP pin, it forces the device into Idle mode and it can begin transmitting or receiving data.
It remains active until it no longer detects data for the time that ST specifies, at which point it resumes its
low-power cyclic state.
Cyclic scanning
Each RF transmission consists of an RF initializer and payload. The RF initializer contains initialization
information and all receiving devices must wake during the wake-up initializer portion of data
transmission in order to synchronize with the transmitting device and receive the data.
The cyclic interval time defined by the SM (Sleep Mode) command must be shorter than the interval time
defined by LH (Wake-up Initializer Timer) command.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 27
Sleep modes
Correct configuration (LH > SM)
In the following figure, the length of the wake-up initializer exceeds the time interval of Cyclic Sleep. The
receiver is guaranteed to detect the wake-up initializer and receive the accompanying payload data.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 28
Operation
When operating at 1 W power output, observe a minimum separation distance of 6 ft (2 m)
between devices. Transmitting in close proximity of other devices can damage the device's
front end.
Serial interface
The XTC RF Module provides a serial interface to an RF link. The XTC RF Module converts serial data to RF
data and sends that data to any over-the-air compatible device in an RF network. The device can
communicate through its serial port with any logic and voltage compatible universal asynchronous
receiver/transmitter (UART), or through a level translator to any serial device.
UART data flow
Devices that have a UART interface can connect directly to the pins of the XTC RF Module as the following
figure shows. The figure shows system data flow in a UART-interfaced environment. Low-asserted signals
have a horizontal line over the signal name.
Serial data
A device sends data to the device's UART through pin 4 (DIN) as an asynchronous serial signal. When the
device is not transmitting data, the signal idles high.
For serial communication to occur, you must configure the UART of both devices with compatible settings
for the baud rate, parity, start bits, stop bits, and data bits. Each data byte consists of a start bit (low), 8
data bits (least significant bit first) and a stop bit (high). The following diagram illustrates the serial bit
pattern of data passing through the device. It shows UART data packet 0x1F (decimal number 31) as
transmitted through the device.
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 29
Flow control
Flow control
The RTS and CTS device pins provide RTS and/or CTS flow control. CTS flow control signals the host to
stop sending serial data to the device. RTS flow control lets the host signal the device so it will not send
the data in the serial transmit buffer out the UART. The following diagram shows the internal data flow,
with the five most common pin signals.
The firmware has Hardware flow control (CTS) configured by default. You must configure CTSflow control
on the host side for it to work.
You must configure Software flow control (XON) on both the host and device side for it to work.
If you change the CS command from 0, then CTSflow control will not work even if you have it configured
on the host.
Data In (DIN) buffer and flow control
When serial data enters the device through the DIN pin (pin 4), it stores the data in the DIN buffer until it
can process the data.
When the firmware satisfies the RB and RO parameter thresholds, the device attempts to initialize an RF
transmission. If the device is already receiving RF data, it stores the serial data in the device's DIN buffer.
The device creates and transmits data packets when it meets one of the following conditions:
XBee/XBee-PRO XTend Compatible (XTC) RF Module User Guide 30
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