Murata DNT24 Series Quick setup guide

Revision History
Revision
Date
Author
Change Description
1.0
10/19/11
F. Perkins
Initial Issue
2.0
10/27/14
R. Willett
Reformatted for new Murata V.I.
RFM products are now
Murata products.
DNT24 Series
2.4 GHz
Spread Spectrum
Wireless Transceivers
Integration Guide
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Important Regulatory Information
Murata Product FCC ID: HSW-DNT24
IC 4492A-DNT24
Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant
to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interfer-
ence in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if
not installed and used in accordance with the instructions, may cause harmful interference to radio communica-
tions. If this equipment does cause harmful interference to radio or television reception, which can be deter-
mined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
1) Re-orientate or relocate the receiving antenna,
2) Increase the separation between the equipment and the radiator,
3) Connect the equipment into an outlet on a circuit different from that to which the receiver is connected,
4) Consult the dealer or an experienced radio/TV technician for help.
FCC Antenna Gain Restriction:
The DNT24 has been designed to operate with any dipole antenna of up to 12 dBi of gain, any corner reflector antenna of
up to 14 dBi gain, any patch antenna of up to 12 dBi gain, or any chip antenna of up to 0 dBi gain. The antenna(s) used
for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be
co-located or operating in conjunction with any other antenna or transmitter.
IC RSS-210 Detachable Antenna Gain Restriction:
This radio transmitter, IC 4492A-DNT24, has been approved by the Industry Canada to operate with the antenna types
listed below with the maximum permissible gain and the required antenna impedance for each antenna type indicated.
Antenna types not included in this list, having a gain greater than the maximum gain indicated for that type, are strictly
prohibited for use with this device.
Le présent émetteur radio IC 4492A-DNT24 a été approuvé par Industrie Canada pour fonctionner
avec les types d'antenne énumérés ci-dessous et ayant un gain admissible maximal et l'impédance requise pour chaque
type d'antenne. Les types d'antenne non inclus dans cette liste, ou dont le gain est supérieur au gain maximal indiqué,
sont strictement interdits pour l'exploitation de l'émetteur.
Type
Model Number
Gain
Impedance
Omnidirectional OD12-2400 12 dBi 50 ohm
Corner SCR14-2400CT 14 dBi 50 ohm
Patch PA2412 12 dBi 50 ohm
Chip FR05-S1-N-0-102 1.7 dBi 50 ohm
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Under Industry Canada regulations, this radio transmitter may only operate using an antenna of a type and maximum (or
lesser) gain approved for the transmitter by Industry Canada. To reduce potential radio interference to other users, the
antenna type and its gain should be so chosen that the equivalent isotropically radiated power (e.i.r.p.) is not more than
that permitted for successful communication.
Conformément à la réglementation d'Industrie Canada, le présent émetteur radio peut fonctionner
avec une antenne d'un type et d'un gain maximal (ou inférieur) approuvé pour l'émetteur par Industrie Canada. Dans le
but de réduire les risques de brouillage radioélectrique à l'intention des autres utilisateurs, il faut choisir le type d'antenne
et son gain de sorte que la puissance isotrope rayonnée équivalente (p.i.r.e.) ne dépasse pas l'intensité nécessaire à
l'établissement d'une communication satisfaisante.
This device complies with Industry Canada licence-exempt RSS standard(s). Operation is subject to the following two
conditions: (1) this device may not cause interference, and (2) this device must accept any interference, including interfer-
ence that may cause undesired operation of the device.
Le présent appareil est conforme aux CNR d'Industrie Canada applicables aux appareils radio exempts de licence. L'ex-
ploitation est autorisée aux deux conditions suivantes : (1) l'appareil ne doit pas produire de brouillage, et (2) l'utilisateur
de l'appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d'en compromettre le
fonctionnement.
See Section 6.8 of this manual for regulatory notices and labeling requirements. Changes or modifications to a DNT24 not
expressly approved by MURATA may void the user’s authority to operate the module.
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Table of Contents
1.0 DNT24 Introduction.....................................................................................................................7
1.1 Why Spread Spectrum?...........................................................................................................7
1.2 Frequency Hopping versus Direct Sequence...........................................................................8
2.0 DNT24 System Overview............................................................................................................9
2.1 Point-to-Point Systems ............................................................................................................9
2.2 Point-to-Multipoint Systems...................................................................................................10
2.3 Store-and-Forward Systems..................................................................................................10
2.4 RF Channel Access...............................................................................................................11
2.5 DNT24 Addressing.................................................................................................................12
2.6 Network Linking and Slot Registration...................................................................................12
2.6.1 Fast Linking Techniques .................................................................................................13
2.7 Transparent and Protocol-formatted Serial Data ...................................................................13
3.0 DNT24 Application Interfaces....................................................................................................14
3.1 Serial Ports............................................................................................................................14
3.2 SPI Port .................................................................................................................................14
3.3 Digital I/O...............................................................................................................................17
3.4 Analog I/O..............................................................................................................................17
3.5 I/O Event Reporting and I/O Binding......................................................................................18
4.0 DNT24 System Configuration....................................................................................................18
4.1 Configuration Parameters......................................................................................................18
4.2 Configuring a Basic Point-to-Point System ............................................................................18
4.3 Configuring a Basic Point-to-Multipoint Point System............................................................19
4.4 Configuring a Customized Point-to-Point or Point-to-Multipoint System................................19
4.5 Configuring a Store-and-Forward System..............................................................................21
4.6 Slot Buffer Sizes, Number of Slots, Messages per Hop and Hop Duration............................21
5.0 DNT24 Application Interface Configuration...............................................................................23
5.1 Configuring the Serial Port.....................................................................................................24
5.2 Configuring the SPI Port........................................................................................................24
5.3 Configuring Digital I/O............................................................................................................25
5.4 Configuring Analog I/O...........................................................................................................25
5.5 Configuring I/O Event Reporting and I/O Binding ..................................................................26
5.6 Configuring Sleep Mode ........................................................................................................27
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

6.0 DNT24 Hardware......................................................................................................................28
6.1 Specifications.........................................................................................................................29
6.2 Module Pin Out......................................................................................................................30
6.3 Antenna Connector................................................................................................................31
6.4 Power Supply and Input Voltages..........................................................................................32
6.5 ESD and Transient Protection ...............................................................................................32
6.6 Interfacing to 5 V Logic Systems ...........................................................................................32
6.7 Mounting and Enclosures ......................................................................................................32
6.8 Labeling and Notices .............................................................................................................33
7.0 DNT24 Protocol-formatted Messages.......................................................................................34
7.1 Protocol Formats....................................................................................................................34
7.2 Message Types .....................................................................................................................34
7.3 Message Format Details........................................................................................................35
7.4 Configuration Parameter Registers........................................................................................42
7.4.1 Bank 0x00 - Transceiver Setup.......................................................................................42
7.4.2 Bank 0x01 - System Settings ..........................................................................................45
7.4.3 Bank 0x02 - Status Parameters.......................................................................................47
7.4.4 Bank 0x03 - Serial and SPI Settings ...............................................................................48
7.4.5 Bank 0x04 - Host Protocol Settings.................................................................................49
7.4.6 Bank 0x05 - I/O Parameters............................................................................................50
7.4.7 Bank 0x06 - I/O Settings .................................................................................................52
7.4.8 Bank 0xFF - Special Functions........................................................................................57
7.5 Protocol-formatted Message Examples.................................................................................58
7.5.1 Data Message.................................................................................................................58
7.5.2 Configuration Messages..................................................................................................58
7.5.3 Sensor Message .............................................................................................................59
7.5.4 Event Message................................................................................................................60
8.0 DNT24DK/DNT24ADK Developer’s Kits...................................................................................61
8.1 Kit Contents...........................................................................................................................61
8.2 Additional Items Needed........................................................................................................61
8.3 Developer’s Kit Default Operating Configuration ...................................................................61
8.4 Developer’s Kit Hardware Assembly......................................................................................62
8.5 Utility Program .......................................................................................................................63
8.6 Initial Kit Operation.................................................................................................................63
8.6.1 Serial Communication and Radio Configuration..............................................................66
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

8.7 Interface Board Features.......................................................................................................73
9.0 Troubleshooting ........................................................................................................................75
9.1 Diagnostic Port Commands...................................................................................................75
10.0 Appendices...............................................................................................................................76
10.1 Ordering Information..............................................................................................................76
10.2 Technical Support..................................................................................................................76
10.3 DNT24 Mechanical Specifications.........................................................................................77
10.4 DNT24 Development Board Schematic.................................................................................81
11.0 Warranty ...................................................................................................................................84
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

1.0 DNT24 Introduction
DNT24 transceivers provide highly-reliable wireless connectivity for point-to-point, point-to-multipoint and store-and-
forward radio applications. Frequency hopping spread spectrum (FHSS) technology ensures maximum resistance to mul-
tipath fading and robustness in the presence of interfering signals, while
operation in the 2.4 GHz ISM band allows license-free use in most regions of the world. The DNT24 supports serial data
rates for host communications from 1.2 to 250.0 kbps, plus three SPI data rates from 125 to 500 kbps. On-board data
buffering plus an error-correcting radio protocol provide smooth data flow and simplify the task of integration with existing
applications. Key DNT24 features include:
•Multipath fading resistant frequency hopping
technology with up to 24 frequency chan-
nels, 2406 to 2475 MHz
•Receiver protected by low-loss SAW filter,
providing excellent receiver sensitivity and
interference rejection important in outdoor
applications
•Ad Hoc TDMA operating mode supports a
large number of remotes with low latency
for burst data streaming
•Simple interface handles both data and con-
trol at up to 250.0 kbps on the serial port or
500 kbps on the SPI port
•Support for point-to-point, point-to-multipoint,
peer-to-peer and store & forward networks
•AES encryption provides protection from
eavesdropping
•FCC 15.247,IC RSS-210 and ETSI certified
for license-free operation
•Nonvolatile memory stores DNT24 configura-
tion when powered off
•Five mile plus range with omnidirectional
antennas (antenna height dependent)
•Selectable 10 or 63 mW transmit power levels
•Transparent ARQ protocol with data
buffering ensures data integrity
•Automatic I/O event reporting mode simplifies
application development
•Analog and Digital I/O supports wireless
sensing applications
•I/O binding mode provides wireless transmis-
sion of analog and digital values
1.1 Why Spread Spectrum?
A radio channel can be very hostile, corrupted by noise, path loss and interfering transmissions from other radios. Even in
an interference-free environment, radio performance faces serious degradation from a phenomenon known as multipath
fading. Multipath fading results when two or more reflected rays of the transmitted signal arrive at the receiving antenna
with opposing phases, thereby partially or completely canceling the signal. This problem is particularly prevalent in indoor
installations. In the frequency
domain, a multipath fade can be described as a frequency-selective notch that shifts in location and
intensity over time as reflections change due to motion of the radio or objects within its range. At any given time, multipath
fades will typically occupy 1% - 2% of the band. From a probabilistic viewpoint, a conventional radio system faces a 1% -
2% chance of signal impairment at any given time due to multipath fading.
Spread spectrum reduces the vulnerability of a radio system to both multipath fading and jammers by distributing the
transmitted signal over a larger region of the frequency band than would otherwise be necessary to send the information.
This allows the signal to be reconstructed even though part of it may be lost or corrupted in transmission.
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Narrow-band versus spread spectrum transmission
Figure 1.1.1
1.2 Frequency Hopping versus Direct Sequence
The two primary approaches to spread spectrum are direct sequence spread spectrum (DSSS) and frequency hopping
spread spectrum (FHSS), either of which can generally be adapted to a given application. Direct sequence spread spec-
trum is produced by multiplying the transmitted data stream by a much faster, noise-like repeating pattern. The ratio by
which this modulating pattern exceeds the bit rate of the base-band data is called the processing gain, and is equal to the
amount of rejection the system affords against narrow-band interference from multipath and jammers. Transmitting the
data signal as usual, but varying the carrier frequency rapidly according to a pseudo-random pattern over a broad range
of channels produces a frequency hopping spectrum system.
Forms of spread spectrum - direct sequence and frequency hopping
Figure 1.1.2
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

One disadvantage of direct sequence systems is that due to design issues related to broadband transmitters and receiv-
ers, they generally employ only a minimal amount of spreading, often no more than the minimum required by the regulat-
ing agencies. For this reason, the ability of DSSS systems to overcome fading and in-band jammers is relatively weak. By
contrast, FHSS systems are capable of hopping throughout the entire band, statistically reducing the chances that a
transmission will be affected by fading or interference. This means that a FHSS system will degrade gracefully as the
band gets noisier, while a DSSS system may exhibit uneven coverage or work well until a certain point and then give out
completely.
Because it offers greater immunity to interfering signals, FHSS is often the preferred choice for co-located systems. Since
direct sequence signals are very wide, they can offer only a few non-overlapping channels, whereas multiple hoppers can
interleave, minimizing interference. Frequency hopping systems do carry some disadvantages, in that they require an ini-
tial acquisition period during which the receiver must lock on to the moving carrier of the transmitter before any data can
be sent, which typically takes several seconds. In summary, frequency hopping systems generally feature greater cover-
age and channel utilization than comparable direct sequence systems. Of course, other implementation factors such as
size, cost, power consumption and ease of implementation must also be considered before a final radio design choice can
be made.
2.0 DNT24 System Overview
A DNT24 radio can be configured to operate in one of three modes - base, remote or router. A base controls a DNT24
system, and interfaces to an application host such as a PC or Internet gateway. A remote functions to transmit or receive
serial, digital (state) and analog data. A router alternates between functioning as a remote on one hop and a network base
on the next hop. When acting as a remote, the router stores messages it receives from its parent, and then repeats the
messages to its child radios when acting as a network base. Likewise, a router will store messages received from its child
radios when acting as a base, and repeat them to its parent when acting as a remote. Any message addressed directly to
a router is processed by the router rather than being repeated.
2.1 Point-to-Point Systems
A DNT24 system contains at least one network. The simplest DNT24 topology is a point-to-point system, as shown in Fig-
ure 2.1.1. This system consists of a base and one remote forming a single network. Point-to-point systems are often used
to replace wired serial connections. Point-to-point systems are also used to transmit switch positions or analog signals
from one location to another.
Figure 2.1.1
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DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

2.2 Point-to-Multipoint Systems
Figure 2.2.1 shows the topology of a point-to-multipoint (star) system, which consists of a base and more than one remote
in a single network. Point-to-multipoint systems are typically used for data, sensor and alarm systems. While most traffic
in a point-to-multipoint system is between the base and the remotes, DNT24 technology also allows for peer-to-peer
communication from one remote to another.
Figure 2.2.1
2.3 Store-and-Forward Systems
Figure 2.3.1 shows the topology of a store-and-forward system, which consists of a base, one or more routers, one or
more remotes, and two or more networks. Networks in a store-and-forward system form around the base and each router.
The base and the routers are referred to as the parents of the networks they form. The rest of the radios in each network
are referred to as child radios. Note that a router is a child of the base or another router while being the parent of its own
network. Each network parent transmits beacons to allow child radios to synchronize with its hopping pattern and join its
network. Different frequency hopping patterns are used by the parent radios in a system, minimizing interference between
networks.
Store-and-forward systems are used to cover larger areas than is possible with point-to-point or point-to-multipoint sys-
tems. The trade-off in store-and-forward systems is longer delivery times due to receiving and retransmitting a message
several times. Store-and-forward systems are especially useful in applications such as agriculture where data is only col-
lected periodically.
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Figure 2.3.1
2.4 RF Channel Access
The time a DNT24 network stays on each frequency in its hopping pattern is called the hop duration or dwell time, which
can be configured from 8 to 100 ms. Radio communication during each dwell is organized as a time division multiple ac-
cess (TDMA) frame. A DNT24 frame begins with a base-mode beacon, followed by 1 to 8 time slots used by the network
children to transmit to their parent, as shown in Figure 2.4.1. A base-mode beacon can include up to 8 messages ad-
dressed to one or more child radios. The number of slots is chosen accommodate the number of children that need to
send messages each hop.
Figure 2.4.1
Each beacon includes the status of all slots - either registered (assigned) or open. When a child radio has information to
transmit to its parent, it randomly selects one of the open slots and transmits all or the first part of its data. If the parent
successfully receives the transmission, it includes the child’s MAC address in the next beacon. This signals the child radio
that the slot is temporarily registered to it, allowing the child to efficiently stream any remaining data to the base hop-by-
hop until it is all sent.
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

If a child radio does not see its address in the next beacon following its transmission, it again randomly selects an open
slot and retransmits its data. During times when there are no open slots, a child radio keeps its data queued and contin-
ues to look for an open slot in each beacon until at least one slot
becomes available. The access method the DNT24 uses is referred to as Ad Hoc TDMA.
2.5 DNT24 Addressing
Each DNT24 has a unique MAC address. The MAC address can be read or bar-code scanned from the label on top of
each radio. A DNT24 radio in any mode (base/router/remote) can be addressed using its MAC address. A DNT24 base
can be addressed using either its MAC address or address 0x000000. A DNT24 can send a message to all other DNT24’s
in its system by using the broadcast address 0xFFFFFF.
The base and all routers (parents) hold base-mode network IDs, which are transmitted in every beacon. All routers and
remotes hold parent network IDs and optionally alternate parent network IDs to compare against the base-mode network
IDs in the beacons they receive. A child router or remote is allowed to join a parent if its parent network ID or alternate
parent network ID matches the parent’s base-mode network ID, or with any parent when its parent network ID is set to
0xFF (wildcard).
In a point-to-point or point-to-multipoint system, the default base-mode network ID of 0xFF (wildcard) can be used. In a
store-and-forward system, however, the base-mode network IDs of all routers must be set to different values between
0x00 to 0x3F. If the base-mode network ID of 0x00 is assigned to a router, the base must be assigned an unused base-
mode network ID between 0x01 and 0x3F. Leaving all parent network IDs in a store-and-forward system set to the default
value of 0xFF allows networks to automatically form, and self-repair if a parent router fails. Enabling the alternate parent
network ID also provides self-repairing message routing.
All DNT24 radios hold a system ID that can be used to distinguish systems that physically overlap. In a DNT24 system,
the system ID must be different from those used by overlapping systems to provide message filtering. Also, using different
base-mode network IDs for all networks in overlapping systems helps reduce hopping pattern collisions.
The store-and-forward path between the base and any other radio in a system can be determined by reading the radio’s
ParentMacAddress parameter. If this address is not the base, then reading the Parent-MacAddress parameter of its par-
ent, grandparent, etc., in succession reveals the complete path to the base. Path determination is useful in optimizing and
troubleshooting systems during commissioning and maintenance.
2.6 Network Linking and Slot Registration
When first turned on, a DNT24 router or remote rapidly scans all frequency channels in its operating band to acquire syn-
chronization and link to a parent based on a system ID match plus a base-mode network ID to parent network ID/alternate
parent network ID match (or by using a wildcard (0xFF) parent network ID).
In addition to the slot status and the MAC addresses of child radios holding slot registrations, each base-mode beacon
includes one of a number of cycled control parameters. The cycled parameters are collected by child radios, allowing
them to register with a parent, and to later follow any control parameter changes. When a router or remote has collected a
full set of cycled parameters, it can issue an optional initial heartbeat message and then optional periodic heartbeat mes-
sages which allow an application to maintain the status of all routers and remotes in its DNT24 system.
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DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

When a router/remote has data to send to its parent, it picks an open slot at random and transmits. It then looks for its
MAC address in the next beacon. If its MAC address is present in the beacon, it is temporarily registered to the slot and
continues to use it until all current data is sent, or its MAC address drops off the beacon.
2.6.1Fast Linking Techniques
Minimizing linking time is important in certain applications. For example, when the remotes in a system are battery pow-
ered and wake from sleep occasionally to report data. Minimizing linking time increases the operating battery life of the
remotes. The basic techniques to reduce linking time include:
- use no more hop duration (dwell time) than necessary
- use no more slots than necessary for the application
- use no larger base slot size (BSS) than necessary
- use no more hops in the hopping pattern than are necessary
- transmit only dynamic cycle parameters once system nodes have static parameters
In the United States and Canada, the DNT24 complies with DTS (DSSS) regulations based on the bandwidth of its trans-
mitted spectrum. In this case, frequency hopping is optional and when frequency hopping is used there is no minimum
requirement on the number of hopping channels that can be used. As discussed in Section 7.4.2., there are two 5-channel
hopping patterns that can be used to help minimize linking time. All DNT24’s in a system must be preset to one of these
5-channel hopping patterns in order to achieve fast linking. Note that the 5-channel hopping patterns cannot be used in
Europe.
Once a complete set of cycled parameters has been receive by all routers and remotes in a system and stored in memory,
it is not necessary to send all of them again during a re-linking, as long as the system configuration remains stable.
As discussed in Section 7.4.1, the base station in a DNT24 system can be configured to transmit “fast beacons” for a pe-
riod of time when powered up, reset or triggered with the FastBeaconTrig parameter. Fast beacons are sent using a very
short hop dwell time, facilitating fast system linking.
2.7 Transparent and Protocol-formatted Serial Data
A DNT24 remote can directly input and output data bytes and data strings on its serial port. This is referred to as trans-
parent serial port operation. In a point-to-point system or in multi-point systems when broadcast addressing is used, the
base can also be configured for transparent serial port operation.
In all other cases, serial data will be protocol formatted:
- configuration commands and replies
- I/O event messages
- announcement messages including heartbeats
Protocol-formatted messages are discussed in detail in Section 7. Briefly, protocol-formatted messages include a start-of-
messages character, message length and message type information, the destination address of the message, and the
message payload.
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DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Transparent data is routed using a remote transparent destination address. In a remote, this address
defaults to the base, 0x000000, and in the base this address defaults to broadcast, 0xFFFFFF. These defaults can be
overridden with specific radio addresses. For example, it is possible to set up transparent peer-to-peer routing between
two remotes in a point-to-multipoint or store-and-forward system by loading specific MAC addresses in each radio’s re-
mote transparent destination address.
3.0 DNT24 Application Interfaces
A DNT24 module provides a variety of application interfaces including two serial ports, an SPI port, six digital I/O ports
(logic state), three 12-bit ADC input ports, and two 12-bit DAC output ports. Each of these interfaces is discussed below.
3.1 Serial Ports
The DNT24 includes two serial ports, one for communication and an optional one for diagnostics. The communication port
is a full-duplex UART interface with hardware flow control on two of the digital I/O pins as an optional feature. One digital
I/O pin can also be configured as an RS485 enable function. The
serial communication port can be configured with baud rates from 1.2 to 250.0 kbps, with 9.6 kbps the default baud rate.
The DNT24 communication port transmits/receives 8-bit data with a choice of even, odd or no parity and 1 or 2 stop bits.
The default configuration is no parity and one stop bit. See Section 5.1 for recommendations on configuring the communi-
cation port, and Section 7.4.4 for detailed information on configuration parameters. The diagnostic port is enabled as an
alternate function on two digital I/O pins, and can be configured with baud rates from 1.2 to 250.0 kbps, with 9.6 kbps the
default baud rate. The diagnostic port transmits/receives 8-bit data with no parity and 1 stop bit. See Section 7.4.8 for di-
agnostic port configuration details.
3.2 SPI Port
The DNT24 serial peripheral interface (SPI) port can operate either as a master or a slave. The port
includes the four standard SPI connections - MISO, MOSI, SCLK and /SS, plus three signals used to support SPI slave
mode operation - /HOST_RTS, /HOST_CTS and DAV. The serial port and SPI master mode can run simultaneously. Se-
rial port operation is disabled when the SPI port is configured for slave mode. Note that all SPI slave mode messages
must be protocol formatted.
Figure 3.2.1
The DNT24 SPI port can run at three clock rates in master mode - 125, 250 or 500 kbps. There are two message sources
available to a DNT24 SPI master, a protocol-formatted RxData message or a stored command. The DNT24 master will
©2009-2014 by Murata Electronics N.A., Inc.
DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

clock a message from either source into its slave and return the bytes clocked out as a protocol-formatted TxData mes-
sage. The DNT24 event timer triggers sending the stored command to the DNT24’s slave. The stored command can be
up to 16 bytes in length. Figure 3.2.1 shows the required SPI master mode-signal connections, and Figure 3.2.2 shows
the SPI master-mode timing.
Figure 3.2.2
In SPI slave mode, the host can stream data into DNT24 at up to 250 kbps, provided the host suspends clocking within 10
bytes following a low-to-high transition on /HOST_CTS. The host can clock data into the DNT24 at up to 4 Mbps for data
bursts of up to 50 bytes, provided the interval from the end of one burst to the start of the next burst is at least 2 ms, and
the host suspends clocking on a low-to-high transition on /HOST_CTS. See Figure 3.2.4
Figure 3.2.3
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DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

Figure 3.2.4
The host should use the following steps to fetch data from a DNT24 SPI slave, as show in Figure 3.2.5:
1. The host sets the /HOST_RTS signal high to allow the DNT24 to signal data available.
2. The DNT24 sets the data available (DAV) high to signal the host it has data.
3. The host set the /SS signal low to enable SPI operation.
4. The host clocks in one dummy byte (ignore the output byte) and then sets /HOST_RTS low.
5. The host begins to clock out the data, which can include several messages.
6. The host continues to clock out data until a 0x00 byte occurs in the byte stream where a 0xFB start-of-message
would be expected.
7. The host has now clocked out all messages and the 0x00 is discarded.
8. The host sets /HOST_RTS and /SS high to allow the DNT24 to signal DAV the next time it
has data.
Note that the DAV signal can go low before the last message is clocked out. It is not a reliable indication that the last byte
of the message(s) has been clocked out. See Section 5.2 for recommendations on configuring the SPI port, and Section
7.4.4 for detailed information on SPI port configuration parameters.
Figure 3.2.5
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3.3 Digital I/O
The DNT24’s six digital (state) I/O ports are labeled GPIO0 through GPIO5. GPIO5 has an alternate function of /HOST_
RTS and GPIO4 of /HOST_CTS, providing hardware handshaking for the serial port and SPI slave mode operation. If se-
rial port hardware handshaking is not required and SPI slave mode is not enabled, GPIO4 and GPIO5 can be used for
other digital I/O functions. When SPI slave mode is enabled, GPIO5 and GPIO4 must be used for /HOST_RTS and
/HOST_CTS respectively, and GPIO3 must be used to provide the DAV signal (SPI slave mode overrides any other con-
figuration for these ports).
Except in SPI slave mode, GPIO0 through GPIO5 are available for customer-defined functions:
- The direction of each GPIO pin can be set for both active and sleep modes.
- The initial state (power on) of all GPIO pins configured as outputs can be set.
- The state of all GPIO pins configured as outputs in sleep mode can be set.
- GPIO triggering of I/O event reporting can be configured.
- GPIO level control of sleep hold-off can be configured.
See Section 5.3 for recommendations on configuring the digital I/O, and Sections 7.4.6 and 7.4.7 for
detailed information on GPIO parameters.
3.4 Analog I/O
The DNT24’s three ADC input channels are labeled ADC0 through ADC2. The ADC can be disabled if unused to reduce
current consumption. The ADC can be operated in either single-ended mode or differential mode. In single-ended mode,
up to three sensor inputs can be measured. The negative sensor
inputs are connected to ground and the positive sensor inputs are connected to ADC0, ADC1 and ADC2 respectively.
Single-ended measurements are unsigned 11-bit values. In differential mode, one or two sensor inputs can be measured
as 12-bit signed values. The first differential measurement is the difference between the voltage on ADC1 and the voltage
on ADC0, and is referred to as the ADC0 differential measurement. The second differential measurement is the difference
between ADC2 and ADC0, and is referred to as the ADC1 differential measurement. Operating the ADC in differential
mode takes advantage of common mode rejection to provide the best measurement stability. Differential mode also incor-
porates a programmable gain preamplifier function, with gains settings from 1 to 64 available.
There are two options for the ADC full-scale reference:
1. The DNT24 regulated supply voltage divided by 1.6, or about 2.06 V
2. A low impedance voltage source applied to the DNT24’s ADC_EXT_REF input pin, 2.7 V maximum. If no connec-
tion is made to this pin, a voltage equal to about 2.7 V will be present.
Note that when differential ADC mode is used, the maximum output voltage available from the preamplifier at any gain
setting is 2.4 V, so the maximum ADC reading that can be made using a 2.7 V ADC reference will be about 88.9% of full
scale. The ADC channels are read each ADC sample interval, which is configurable. High and low measurement thresh-
olds can be set for each ADC channel to trigger I/O event reporting messages.
The DNT24’s two DAC outputs are labeled DAC0 and DAC1. The DACs can be disabled if unused to reduce current con-
sumption. The DAC settings have 12-bit resolution. There are two options for the DAC full-scale reference:
1. The DNT24 regulated supply voltage, about 3.3 V
2. A low impedance voltage source applied to the DNT24’s ADC_EXT_REF input pin, 2.7 V maximum. If no connec-
tion is made to this pin, a voltage equal to about 2.7 V will be present.
See Section 5.4 for recommendations on configuring the analog I/O, and Sections 7.4.6 and 7.4.7 for
detailed information on analog I/O parameters.
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DNT24 Integration Guide R2.0 - 10/27/14 www.murata.com

3.5 I/O Event Reporting and I/O Binding
The DNT24’s I/O event reporting function can generate a protocol-formatted RxEvent message when triggered by one of
the following I/O events:
- A specific state change of GPIO0, GPIO1, GPIO2 or GPIO3.
- Firing of the periodic event report timer.
- A high or low threshold exceeded on a measurement by ADC0, ADC1 or ADC2.
An I/O report message includes:
- The states of GPIO0 through GPIO5.
- The latest measurements made by ADC0 through ADC2 .
- A set of flags indicating which event(s) triggered the I/O report.
- The settings of DAC0 and DAC1.
The I/O binding function works in conjunction with I/O event reporting. When I/O binding is enabled on a DNT24, data re-
ceived in an I/O event report it is mapped as follows:
- GPIO2 will output the state of GPIO0 in the last received event report.
- GPIO3 will output the state of GPIO1 in the last received event report.
- DAC0 will output the voltage read by ADC0 in the last received event report.
- DAC1 will output the voltage read by ADC1 in the last received event report.
I/O binding is used to transmit switch positions or analog signals from one location to another. Note that I/O binding can-
not be used in a DNT24 when SPI slave mode is enabled or differential ADC mode is used. See Section 5.4 for recom-
mendations on configuring I/O event reporting and binding, and Sections 7.4.6 and 7.4.7 for detailed information on I/O
reporting and binding parameters.
4.0 DNT24 System Configuration
DNT24 radios feature an extensive set of configuration options that allows them to be adapted to a wide range of applica-
tions. Configuration defaults have been carefully selected to minimize the configuration effort for most applications, while
providing the ability to individually adjust the configuration of each radio to achieve highly optimized system operation.
4.1 Configuration Parameters
The configuration of a DNT24 is controlled by a set of parameters (registers). Parameters that address a particular aspect
of operation are grouped into a bank. All parameters can be accessed through a module’s serial port and over the radio
link. Most parameters are read/write. Read-only parameters include fixed values such a MAC addresses, firmware version
numbers and parameters that are dynamically
adjusted during system operation such as link status. Write-only parameters include security keys and certain action trig-
gers such as reset. Incorrectly configuring certain parameters can disable a module’s radio link, but the configuration can
always be corrected through the serial port. The organization of the parameter register banks and the details of each pa-
rameter are covered in Section 7.4 of this guide. Sections 4.2 through 5.7 discuss which parameters apply to various as-
pects of configuring a DNT24 system, network or application interface.
4.2 Configuring a Basic Point-to-Point System
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A basic DNT24 point-to-point system is suitable for many serial data applications. The default configuration of a
DNT24 is a remote with the serial port configured for transparent operation at 9.6 kbps, 8N1. To configure a basic
point-to-point system:
1. Configure one of the modules as a base by setting the DeviceMode parameter in Bank 0 to 0x01.
2. Set the MemorySave parameter in Bank 0xFF to 0xD2, which will save the DeviceMode parameter to EEPROM
and reset the module, enabling base operation.
3. All other parameters may be left at their default values.
4.3 Configuring a Basic Point-to-Multipoint Point System
A basic DNT24 point-to-multipoint point systems is suitable for many serial data applications where multiple remotes
are used. The default configuration of a DNT24 is a remote with the serial port configured for transparent operation at
9.6 kbps, 8N1. To configure a basic point-to-multipoint system:
1. Configure one of the modules as a base by setting the DeviceMode parameter in Bank 0 to 0x01.
2. If the host application driving the base will individually communicate each remote, set the ProtocolMode parame-
ter in Bank 4 of the base to 0x01. This step is not required if messages from the base to the remotes will always
be broadcast and/or the base does not need to know the MAC address of the remote sending a message.
3. Set the MemorySave parameter in Bank 0xFF to 0xD2, which will save the DeviceMode parameter to EEPROM
and reset the module, enabling base operation.
4. All other parameters may be left at their default values.
5. If the host application driving the base will individually communicate with each remote, the MAC address for each
remote can be obtained from announce packets, heartbeat packets, a ForceDiscover command, or by reading or
scanning the MAC address from the label on top of each remote.
4.4 Configuring a Customized Point-to-Point or Point-to-Multipoint System
The DNT24 includes many configuration parameters that allow extensive customization of a point-to-point or point-to-
multipoint system. Most applications will require only a few of these parameters be changed from their default values. But
for those applications that need them, MURATA recommends the following configuration sequence. Skip the configuration
steps where the default parameter value is satisfactory.
1. Configure one of the modules as a base by setting the DeviceMode parameter in Bank 0 to 0x01.
2. Set the optional AES security key in all system radios by loading your selected 16-byte string into the SecurityKey
parameter in Bank 0 (the default is 16 bytes of 0x00).
3. Select the frequency band of operation by setting the FrequencyBand parameter in Bank 1 of the base radio as
desired (the default is Band 0).
4. Set the transmitter power level as needed in all radios by setting the TxPower parameter in Bank 0 (the default is
63 mW).
5. Configure the system ID in all radios by setting the SystemID parameter in Bank 0 (the default is OK if there is no
chance of overlapping systems).
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6. Load the parent network ID in all remotes in the ParentNetworkID parameter in Bank 0 as needed (wildcard de-
fault is OK for point-to-point and point-to-multipoint systems).
7. Set the BaseModeNetID parameter in the base to match the ParentNetworkID parameter in the remotes if the de-
fault BaseModeNetID is not used in the base and the wildcard default ParentNetworkID is not used in the remotes.
8. For a point-to-multipoint system where DNT24 MAC addressing will be used, set the ProtocolMode parameter in
Bank 4 of the base to 0x01. Set the protocol mode as needed in the base and remote of a point-to-point system,
and as needed in the remotes in a point-to-multipoint system. If SPI slave mode will be used, protocol mode must
be enabled in all system radios. Note that if the application data includes addressing information for individual re-
mote hosts, the DNT24 broadcast mode can be used instead of the DNT24 protocol mode.
9. If using transparent serial mode in the system:
a. Set the remote transparent destination address in the RmtTransDestAddr parameter, Bank 0, in each re-
mote if the destination is not the base (the base address is the default destination).
b. Set the transparent point-to-point mode to select either the RmtTransDestAddr address (default) or the
address of the originator of the last received message as the remote destination address. The parameter
that controls this destination address is the Trans-PtToPtMode in Bank 4. Set in all remotes as needed.
c. Set the timeout for transmission of transparent data in the remotes as needed. The parameter that con-
trols the timeout is the TxTimeout in Bank 4 (the default is to send as soon as possible).
d. Set the minimum message length for transmission of transparent data in the remotes as needed. The pa-
rameter that controls the length is the MinPacketLength in Bank 4 (the default is one byte).
10. Refer to Section 4.6 below which discusses how to coordinate the values of the following four
parameters:
a. Set the maximum number of messages that can be sent in a hop on each system radio. The parameter
that controls this number is MsgsPerHop in Bank 4. The default is 8 messages.
b. Load the required base slot size into the BaseSlotSize parameter, Bank 1, in the base. The default is 40
bytes.
c. Configure the number of child slots per hop on the base by setting the NumSlots parameter. The default
is 3 slots.
d. Set the required hop duration on the base. The HopDuration parameter in Bank 0 controls hop duration.
The default is 20 ms.
11. Configure the slot lease on the base by setting the SlotLease parameter. The default is 4 hops.
12. Set the heartbeat interval as required in each system radio. The parameter that controls heartbeats is the Heart-
BeatIntrvl in Bank 0. The default is 20 seconds/heartbeat.
13. Enable end-to-end message ACKs where required by setting the EndToEndAckEnable parameter in Bank 0 to 1.
Enabling this parameter provides a confirmation that a message has reached its destination in peer-to-peer or
store-and-forward routing. The default is disabled.
14. Set the message retry limit on the base with the ArqAttemptLimit parameter in Bank 1. The default value is 6 re-
tries.
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