Murata Electronics North America DNT90E User Manual

IC Radio Standards Specification: RSS-247

Manufacturer: Murata Electronics North America

Certification Exhibit

FCC ID: HSW-DNT90E

IC: 4492A-DNT90E

FCC Rule Part: 15.247

ACS Project Number: 16-0152

Models: DNT90EC, DNT90EP

Manual

5015 B.U. Bowman Drive Buford, GA 30518 USA Voice: 770-831-8048 Fax: [phone]

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DNT90E Integration Guide - 04/13/16

DNT90E Series

900 MHz Spread Spectrum

Wireless Transceivers

Integration Guide

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Important Regulatory Information

Murata Product FCC ID: HSW­DNT90E IC 4492A-DNT90E

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 pro- tection against harmful interference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and
used in accordance with the in- structions, may cause harmful interference to radio
communications. If this equipment does cause harmful interference to radio or television
reception, which can be determined 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.

Warning: Changes or modifications to this device not expressly approved by MURATA could void the user’s authority
to operate the equipment.

FCC Antenna Gain Restriction and MPE Statement:

The DNT90E has been designed to operate with any dipole antenna of up to 5 dBi of gain, or any Yagi of
up to 6dBi gain.

This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This
equipment should be installed and operated with minimum distance 21 cm between the radiator and your
body. This transmitter must not be co-located or operating in conjunction with any other antenna or
transmitter.

Cet équipement est conforme aux limites d'exposition aux radiations définies pour un environnement non
contrôlé. Cet équipement doit être installé et utilisé à une distance minimale de 21 cm entre le radiateur et
votre corps. Cet émetteur ne doit pas être situé ou opérant en conjonction avec une autre antenne ou
émetteur.

Notices:

WARNING: This device operates under Part 15 of the FCC rules. Any modification to this device, not
expressly authorized by MURATA, Inc., may void the user’s authority to operate this device.

FCC NOTICE: This device complies with Part 15 of the FCC rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.

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Innovation, Science, and Economic Development (ISED) Canada Notice: This device complies with ISED

Canada’s licence-exempt RSSs. Operation is subject to the following two conditions:

(1) This device may not cause interference; and

(2) This device must accept any interference, including interference that may cause undesired operation of
the device.

Le présent appareil est conforme aux CNR ISED Canada applicables aux appareils radio
exempts de licence. L'exploitation 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.

ISED RSS-247 Detachable Antenna Gain Restriction:

This radio transmitter (DNT90E), has been approved by ISED Canada to operate with the antenna types
listed below with the maximum permissible gain and required antenna impedance for each antenna type
indicated. Antenna types not included in this list, or having a gain greater than the maximum gain indicated
for that type, are strictly prohibited for use with this device.

Le présent émetteur radio (DNT90E ) a été approuvé par ISED 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.

Antennas not included in this list or having a gain greater than 6 dB are strictly prohibited for use with
this device. The required antenna impedance is 50 ohms:

OMNI095 Omnidirectional Dipole Antenna, 5 dBi
YAGI099 Directional Antenna, 6 dBi

See Section 6.8 of this manual for regulatory notices and labeling requirements. Changes or modifica­tions to a DNT90E not expressly approved by MURATA may void the user’s authorityto operate the
module.

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Table of Contents

1.1 DNT90E Introduction........................................................................................................................ 6

1.2 Why Spread Spectrum?.............................................................................................................6

1.3 Frequency Hopping versus Direct Sequence ............................................................................7

2.1 DNT90E System Overview............................................................................................................... 8

2.2 Point-to-Point Systems ..............................................................................................................8

2.3 Point-to-Multipoint Systems....................................................................................................... 9

2.4 Store-and-Forward Systems......................................................................................................9

2.5 RF Channel Access................................................................................................................. 10

2.6 DNT90E Addressing................................................................................................................11

2.7 Network Linking and Slot Registration.....................................................................................11

2.6.1 Fast Linking Techniques ................................................................................................... 12

2.7 Transparent and Protocol-formatted Serial Data.....................................................................12

3.1 DNT90E Application Interfaces ......................................................................................................13

3.2 Serial Ports .............................................................................................................................. 13

3.3 SPI Port....................................................................................................................................13

3.4 Digital I/O.................................................................................................................................16

3.5 Analog I/O................................................................................................................................16

3.6 I/O Event Reporting and I/O Binding........................................................................................17

4.1 DNT90E System Configuration ......................................................................................................18

4.2 Configuration Parameters........................................................................................................ 18

4.3 Configuring a Basic Point-to-Point System..............................................................................18

4.4 Configuring a Basic Point-to-Multipoint System.......................................................................18

4.5 Configuring a Customized Point-to-Point or Point-to-Multipoint System.................................. 19

4.6 Configuring a Store-and-Forward System................................................................................ 20

4.7 Slot Buffer Sizes, Number of Slots, Messages per Hop and Hop Duration .............................21

5.1 DNT90E Application Interface Configuration......................................................................................23

5.2 Configuring the Serial Port....................................................................................................... 23

5.3 Configuring the SPI Port.......................................................................................................... 24

5.4 Configuring Digital I/O.............................................................................................................. 24

5.5 Configuring Analog I/O.............................................................................................................24

5.6 Configuring I/O Event Reporting and I/O Binding ....................................................................25

5.7 Configuring Sleep Mode ..........................................................................................................26

6.1 DNT90E Hardware.........................................................................................................................27

6.2 Electrical Specifications........................................................................................................... 28

6.3 Module Pin Out........................................................................................................................ 29

6.4 Antenna Connector..................................................................................................................30

6.5 Power Supply and Input Voltages............................................................................................31

6.6 ESD and Transient Protection......................................................................................................31

6.7 Interfacing to 5 V Logic Systems .............................................................................................31

6.8 Mounting and Enclosures........................................................................................................ 31

6.9 Labeling and Notices ............................................................................................................... 32

7.1 DNT90E Protocol-formattedMessages.......................................................................................... 33

7.2 Protocol Formats......................................................................................................................33

7.3 Message Types........................................................................................................................33

7.4 Message Format Details.......................................................................................................... 34

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7.5 Configuration Parameter Registers..........................................................................................41

7.5.1 Bank 0x00 - Transceiver Setup......................................................................................... 41

7.5.2 Bank 0x01 - System Settings............................................................................................ 44

7.5.3 Bank 0x02 - Status Parameters ........................................................................................ 45

7.5.4 Bank 0x03 - Serial and SPI Settings.................................................................................47

7.5.5 Bank 0x04 - Host Protocol Settings...................................................................................48

7.5.6 Bank 0x05 - I/O Parameters..............................................................................................49

7.5.7 Bank 0x06 - I/O Settings ...................................................................................................50

7.5.8 Bank 0x0FF - Special Functions........................................................................................ 55

7.5 Protocol-formatted Message Examples...................................................................................56

7.5.1 Data Message................................................................................................................... 56

7.5.2 Configuration Message ..................................................................................................... 57

7.5.3 Sensor Message ............................................................................................................... 57

7.5.4 Event Message..................................................................................................................58

8.1 DNT90EDK Developer’s Kit............................................................................................................ 59

8.2 DNT90EDK Kit Contents..........................................................................................................59

8.3 Additional Items Needed..........................................................................................................59

8.4 Developer’s Kit Default Operating Configuration......................................................................59

8.5 Developer’s Kit Hardware Assembly........................................................................................ 60

8.6 DNT90E Utility Program...........................................................................................................61

8.7 Initial Kit Operation...................................................................................................................62

8.6.1 Serial Communication and Radio Configuration................................................................65

8.7 DNT90E Interface Board Features .......................................................................................... 71

9.1 Troubleshooting.............................................................................................................................. 73

9.2 Diagnostic Port Commands.....................................................................................................73

10.1 Appendices..................................................................................................................................... 74

10.2 Ordering Information................................................................................................................ 74

10.3 Technical Support....................................................................................................................74

10.4 DNT90E Mechanical Specifications......................................................................................... 75

10.5 DNT90E Development Board Schematic................................................................................. 77

11.0

Warranty.........................................................................................................................................80

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1.1

DNT90EIntroduction

DNT90E 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 multipath fading and robustness in the presence of interfering signals, while oper­ation in the 900 MHz ISM band allows license-free use in North America, South America and Australia.
The DNT90E supports serial data rates for host communications from 1.2 to 250 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 DNT90E features in­clude:

 Multipath fading resistant frequency hopping

technology with up to 52 frequency chan­nels, 902.76 to 927.24 MHz

 Receiver protected by low-loss SAW filter,

providing excellent receiver sensitivity and
interference rejection important in outdoor
applications

 Support for point-to-point, point-to-multipoint,

peer-to-peer and store & forward networks

 FCC 15.247 and ISED RSS-247 certified

for license-free operation

 Five mile plus range with omnidirectional

antennas (antenna height dependent)

 Transparent ARQ protocolwith data

buffering ensures data integrity

 Analog and Digital I/O supports wireless

sensing 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 kbps on the serial port or
500 kbps on the SPI port

 AES encryption provides protection from

eavesdropping

 Nonvolatile memory stores DNT90E

configura- tion when powered off

 Selectable +16 dBm (40 mW) or +25 dBm

(316 mW) transmit power levels

 Automatic I/O event reporting mode simplifies

application development

 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
phenomenonknown 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.

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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 spectrum is produced by multiplying the transmitted data stream bya 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-bandinterference 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

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One disadvantage of direct sequence systems is that due to design issues related to broadband transmit­ters and receivers, they generally employ only a minimal amount of spreading, often no more than the
minimum required by the regulating 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 onlya few non-overlappingchan­nels, whereas multiple hoppers can interleave, minimizing interference. Frequency hopping systems do
carry some disadvantages, in that they require an initial 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 coverage 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 DNT90E System Overview

A DNT90E radio can be configured to operate in one of three modes - base, remote or router. A base
con- trols a DNT90E 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
func- tioning 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 act- ing 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 bythe router rather than being repeated.

2.1 Point-to-Point Systems

A DNT90E system contains at least one network. The simplest DNT90Etopology is a point-to-point
system, as shown in Figure 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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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,
DNT90E technology also allows for peer-to-peer communication from one remote to another.

Figure 2.2.1

2.3 Store-and-ForwardSystems

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 to­multipoint systems. 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 collected periodically.

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S y s t e m / N e t w o r k

M e s s a

M e s
s a g e

O

O

2.4 RF Channel Access

Figure 2.3.1

The time a DNT90E 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 access (TDMA) frame. A DNT90E frame begins with a base-mode
beacon, followed by 1 to 8 time slots used bythe network children to transmit to their parent, as shown in
Figure

2.4.1. A base-mode beacon can include up to 8 messages addressed to one or more child radios. The
number of slots is chosen accommodate the number of children that need to send messages each hop.

E x a m p l e D N T 9 0 C o m m u n i c a t i o n F
r a m e

B a s e -

p

n

s s i g n e d

p e n

B e a c

S

S l o

S l

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.

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

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keeps its data queued and continues to look for an open slot in each beacon until at least one slot be­comes available. The access method the DNT90E uses is referred to as Ad Hoc TDMA.

2.5 DNT90E Addressing

Each DNT90E has a unique MAC address. The MAC address can be read or bar-code scanned from
the label on top of each radio. A DNT90E radio in any mode (base/router/remote) can be addressed
using its MAC address. A DNT90E base can be addressed using either its MAC address or address
0x000000. A DNT90E can send a message to all other DNT90E’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 net-
work 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 DNT90E radios hold a system ID that can be used to distinguish systems that physically overlap. In a
DNT90E system, the system ID must be different from those used by overlapping systems to provide
mes- sage 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
ParentMacAddress parameter of its parent, 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 DNT90E router or remote rapidly scans all frequency channels in its operating
band to acquire synchronization 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 base­mode 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 messages which allow an application to
maintain the status of all routers and remotes in its DNT90E system.

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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.

2.6.1 Fast Linking Techniques

Minimizing linking time is important in certain applications. For example, when the remotes in a system
are battery powered 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

- transmit only dynamic cycle parameters once system nodes have static parameters

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 DNT90E system can be configured to transmit “fast
beacons” for a period 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 DNT90E remote can directly input and output data bytes and data strings on its serial port. This is re­ferred to as transparent serial port operation. In a point-to-point system, the base can also be configured
for transparent serial port operation.

In all other cases, serial data must 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.

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 remote transparent destination address.

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3.0 DNT90E Application Interfaces

A DNT90E 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 DNT90E 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 an optionalfeature. 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 kbps, with 9.6 kbps the default
baud rate. The DNT90E 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 5.1for rec­ommendations on configuring the communication 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 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 diagnostic port
configuration details.

3.2 SPI Port

The DNT90E 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. Serial port operation is disabled when the SPI port is configured for slave
mode. Note that all SPI slave mode messages must be protocol formatted.

D N T 9 0 S P I M a s t e r M o d e S i g n a l i n
g

Figure 3.2.1
The DNT90E SPI port can run at three clock rates in master mode - 125, 250 or 500 kbps. There are two
message sources available to a DNT90E SPI master, a protocol-formatted RxData message or a stored
command. The DNT90E master will clock a message from either source into its slave and return the bytes
clocked out as a protocol-formatted TxData message. The DNT90E event timer triggers sending the
stored command to the DNT90E’s slave. The stored command can be up to 16 bytes in length. Figure

P e r i p h
e r a l

D N T 9
0

M O S I

S C L K

/ S S

M

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3.2.1

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shows the required SPI master mode-signal connections, and Figure 3.2.2 shows the SPI master-mode
timing.

D N T 9 0 S P I M a s t e r M o d e O p e r a t i o n

/ S S

S C L K

M O S I

M I S O

Figure 3.2.2
In SPI slave mode, the host can stream data into DNT90E 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 DNT90E 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

D N T 9 0 S P I S l a v e M o d e S i g n a l i n
g

H o s t

M

I

O

D N T
9 0

M

O

S I

S

C

K

/ S S

/ H

OTR

S

/ H

OTC

S

D

A V

Figure 3.2.3

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D N T 9 0 S P I S l a v e M o d e M e s s a g e L o a d

/ S S

/ H O S T C T S

S C L K

M O S I

Figure 3.2.4

The host should use the following steps to fetch data from a DNT90E SPI slave, as show in Figure 3.2.5:

1. The host sets the /HOST_RTS signal high to allow the DNT90E to signal data available.

2. The DNT90E 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 DNT90E 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.

D N T 9 0 S P I S l a v e M o d e R X M e s s a g e R e t r i e v a l

D A V

/ S S

/ H O S T R T S

S C L K

M I S O

Figure 3.2.5

S P I B it C l o c k

M e s s a g e t o D N

S P I C l o c k

P r o t o c o l F o r m a t t e d R X M e s

L e n g t h B y t e
0 x F B S t a r t o f M e s s a g e

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3.3 Digital I/O

The DNT90E’s six digital (state) I/O ports are labeled GPIO0 through GPIO5. GPIO5 has an alternate
func- tion of /HOST_ RTS and GPIO4 of /HOST_CTS, providing hardware handshaking for the serial
port and SPI slave mode operation. If serial 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 configuration for
these ports). Ex- cept 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 DNT90E’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-endedmode, up to three sensor inputs can bemeasured. 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-bitsigned 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 differentialmeasurement 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 in­corporates 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 DNT90E regulated supply voltage divided by 1.6, or about 2.06 V

2. A low impedance voltage source applied to the DNT90E’s ADC_EXT_REF input pin, 2.7 V
maxi- mum. If no connection 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 thresholds can be set for each ADC channel to trigger I/O event
reporting messages.

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The DNT90E’s two DAC outputs are labeled DAC0 and DAC1. The DACs can be disabled if unused to
re- duce current consumption. The DAC settings have 12-bit resolution. There are two options for the
DAC full-scale reference:

1. The DNT90E regulated supply voltage, about 3.3 V

2. A low impedance voltage source applied to the DNT90E’s ADC_EXT_REF input pin, 2.7 V
maxi- mum. If no connection 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.

3.5 I/O Event Reporting and I/O Binding

The DNT90E’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 ameasurement 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
DNT90E, data received 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 analogsignals from one location to another. Note that
I/O binding cannot be used in a DNT90E when SPI slave mode is enabled or differential ADC mode is
used. See Section 5.4 for recommendations 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.

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4.0 DNT90E System Configuration

DNT90E radios feature an extensive set of configuration options that allows them to be adapted to a wide
range of applications. 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 DNT90E 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 triggers 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 parameter are covered in Section 7.4 of this guide. Sections

4.2 through 5.7 discuss which parameters apply to various aspects of configuring a DNT90E system, net­work or application interface.

4.2 Configuring a BasicPoint-to-Point System

A basic DNT90E point-to-point system is suitable for many serial data applications. The default
config- uration of a DNT90E 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 oneof 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 willsave 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 DNT90E point-to-multipoint point systems is suitable for many serial data applications where
multiple remotes are used. The default configuration of a DNT90E 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 oneof 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 Proto-
colMode parameter 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 willsave the DeviceMode parame­ter to EEPROM and reset the module, enabling base operation.

4. All other parameters may be left at their default values.

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5. If the host application driving the base will individually communicate each remote, read or scan
the MAC addresses from the label on top of each remote and load the addresses in the host ap­plication data base.

4.4 Configuring a Customized Point-to-Pointor Point-to-Multipoint System

The DNT90E includes many configuration parameters that allow extensive customization of a point-to­point 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 con- figuration sequence. Skip the configuration steps where the default parameter value is
satisfactory.

1. Configure oneof 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 158 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).

6. Load the parent network ID in all remotes in the ParentNetworkID parameter in Bank 0 as needed
(wildcard default is OK for point-to-point and point-to-multipoint systems).

7. Set the BaseModeNetID parameter in the base to match the ParentNetworkID parameter inthe
remotes if the default BaseModeNetID is not used in the base and the wildcard default Parent-
NetworkID is not used in the remotes.

8. For a point-to-multipoint system where DNT90E MAC addressing will be used, set the Proto-
colMode 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 willbe used, protocol mode must be enabled in all system radios. Note
that if the application data includes addressing information for individual remote hosts, the
DNT90E broadcast mode can be used instead of the DNT90E protocol mode.

9. If using transparent serialmode in the system:

a. Set the remote transparent destination address in the RmtTransDestAddr parameter,

Bank 0, in each remote 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 inthe remotes as needed. The pa-

rameter that controls the timeout is the TxTimeout in Bank 4 (the default is no timeout).

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d. Set the minimum message length for transmission of transparent data in the remotes as

needed. The parameter 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 parame-

ter. The default is 3 slots.

d. Set the required hop duration on the base. The HopDuration parameter in Bank 0 con-

trols 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 HeartBeatIntrvl 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 retries.

15. Set the link drop threshold on the base by setting the LinkDropThreshold in Bank 1. This parame­ter sets the number of sequential hops without receiving a beacon that will trigger a child to re­synchronize and re-link to its parent. The default is 10 hops.

16. Set the point-to-point reply timeout on the base in the P2PReplyTimeout parameter in Bank 1.
The default is 16 hops. See Section 7.4.2 for parameter details.

17. Configure the registration timeout on the base by setting the RegistryTimeout parameter in
Bank 1. The default timeout is 50 hops. See Section 7.4.2 for a discussion of this parameter.

18. Load an optional “friendly description” in each system radio in the UserTag parameter, Bank 0.

4.5 Configuring a Store-and-Forward System

The following additional parameters must be set to configure a DNT90E store-and-forward system:

1. Configure the DNT90E radios designated to be routers by setting the DeviceMode
parameter in Bank 0 to 0x02.

2. Enable store-and-forward operation on all system radios by setting the Store&ForwardEn
parameter in Bank 0 to 0x01.

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3. In each router, load a unique base-mode network ID into the BaseModeNetID parameter in Bank
0, and into the base if a router is set to 0x00.

4. To configure a specific system topology, set the parent network ID parameter, ParentNwkID, and
optionally the alternate parent network ID parameter, AltParentNwkID, in all routers and remotes.
Note that a store-and-forward system topology can be formed either automatically or
manually, based on the settings of the ParentNetworkID and optionally the AltParentNwkID
parameters:

- Setting the ParentNwkID parameter to 0xFF in all routers and remotes allows each
router and remote to automatically link to a parent, causing the system to form
automatically (child routers picking each other as a parent cannot occur). In this case, the
AltParent-NwkID parameter should be set to 0xFF, which disables it.

- Setting the ParentNwkID and optionallythe AltParentNwkID parameters to specific val­ues in each router and remote allows full manual control of the network topology.

The benefit of automatic system formation is self-healing. If a parent router fails, its child nodes
can re-link to any other parent router they can receive. However, automatic topology formation
can result in an unnecessarynumber of hops between routers or remotes and the base.

The benefit of manual system topology formation is to avoid unnecessary extra hops in the sys­tem, and to balance the number of children supported by each parent router. If a parent router
fails and an active alternate parent network ID has not been assigned, all children downstream
from the failure will be off the system until the failed router is repaired or replaced.

4.6 Slot Buffer Sizes, Number of Slots, Messages per Hop and Hop Duration

The base slot size (BSS) sets the maximum number of payload bytes the base can transmit during a sin­gle hop when the base is sending one message per hop. The maximum BSS is 105 bytes when a
DNT90E system is configured for one slot. Adding additional slots reduces the maximum BSS by three
bytes per slot. The BSS buffer is set nine bytes larger than the BSS, to a maximum of 114 bytes. The
base can po- tentially send more than one message per beacon, up to the limit set by its MsgsPerHop
parameter value. Each message in the BSS buffer occupies nine header bytes plus the payload.

For example, the base can send three messages per hop when the BSS is 90 bytes, provided the total
payload bytes in the three messages is 72 bytes or less:

slot size = 90
buffer

= 90 + 9 = 99
3 headers = 3*9 = 27
net for payload = 99 - 27 = 72

The BSS must be large enough to accommodate any protocol-formatted message that may be sent over
the wireless link, as each protocol-formatted message must be sent in a single transmission.

The remote slot size (RSS) is the maximum number of payload bytes a child can transmit during a single
hop when it is sending one message per hop. The RSS is the same for all slots. The maximum RSS is
109 bytes. The RSS buffer is set nine bytes larger than the RSS, to a maximum of 118 bytes. A child can
potentially send more than one messagein a slot, up to the limit set by its MsgsPerHop parameter value.
Each message in the transmit buffer occupies nine header bytes plus the payload. For example, a child

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can send two messages per hop when the RSS is 73 bytes, provided the total payload in the two mes­sages is 64 bytes or less:

slot size = 73
buffer

= 73 + 9 = 82
2 headers = 2*9 = 18
net for payload = 82 - 18 = 64

Note that the RSS is calculated by all DNT90Es in a system, rather than being a user configured parame­ter. The slot size depends on the current values of the following parameters:

- base slot size

- hop duration

- number of slots in a frame

The system must be configured such that the RSS is big enough to hold the longest protocol message a
remote will send. This is done by setting the appropriate hop duration for the chosen BSS and number of
slots. The required hop duration for a specific number of slots, base slot size and remote slot size is cal­culated as follows:

HD hop duration in µs
NS number of slots
BSS base slot size in bytes
RSS remote slot size in bytes

HD = NS*(80*RSS + 2440) + 80*BSS + 3280 (round HD up to an even multiple of 500 µs)

Example:

NS = 4
BSS = 96
RSS = 109

HD = 4*(80*109 + 2440) + 80*96 + 3280
HD = 44640 + 7680 + 3280
HD = 55600 round to 56000 µs = 56 ms

ExcelFormatted Equations (load the Excelanalysis ToolPak add-in for the QUOTIENT function):

ABC

D

E

1

Slots

BSS

RSS

Hop Duration in µs

Hop Duration in ms,Rounded

2

Up to the next 0.5 ms Step

3

12020

=A3*(80*C3+2440) + 80*B3 + 3280

=0.5*QUOTIENT((D3+499),500)

For transparent serial port operation without using hardware flow control, the BSS and RSS must be large
enough to accommodate all message bytes that can accumulate between transmissions. The required
BSS and RSS for protocol-formatted messages sent over the wireless link are shown in Table 7.3.1. For
example, the BSS and RSS size required for a TxData protocol-formatted message is three bytes less
than the value in the length byte field of the formatted message.

The default BSS is 40 bytes, number of slots is 3 and hop duration is 20 ms. These parameter settings
provide a 25 byte RSS. These default settings are suitable for point-to-point and small to medium point­to-multipoint systems operating with protocol-formatted and/or transparent messages. To accommodate

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all configuration commands, replies, event messages and announce messages, a 20 byte minimum slot
size is required.

The NumSlots and the MsgsPerHop parameters both affect the number of messages that can be sent on
each hop. The distinction between these parameters is as follows:

- The NumSlots parameter controls the maximum number of individual children that can send

messages to a parent on each hop.

- The MsgsPerHop parameter controls the maximum number of messages a parent or child can

send on each hop.

The NumSlots parameter is configurable only for the base. The base then communicates the NumSlots
value to all other radios in its system. The NumSlots parameter can be set to one for a point-to-point sys­tem, as there is only one child radio. The NumSlots parameter can be set to allow up to eight children to
send messages to their parent during a hop. As discussed above, the hop duration must be increased as
the number of slots are increased to achieve a specific RSS. The default NumSlots parameter value of
three is suitable for manyapplications.

De facto TDMA operation (guaranteed bandwidth) can be implemented for up to 8 remotes by setting the
SlotLease parameter to a value greater than any gaps in data being sent to a remote by its local host.

This will insure that the base keeps each remote’s slot reserved for it even when there is a gap in the da­ta.

The MsgsPerHop parameter is configurable for each DNT90E in a system. This parameter is usually set
to a high value in the base and the routers, allowing traffic between a parent and multiple children on
each hop. The MsgsPerHop parameter has little effect in remotes except when a remote needs to send
multi- ple peer-to-peer messages during a hop. To support sending multiple messages on each hop, the
BSS and RSS must be sized accordingly, requiring a longer hop duration. Note that the messages must
be protocol messages and all messages to be sent on a single hop must be in the module before the
module begins to transmit.

5.0 DNT90E Application Interface Configuration

DNT90E modules include a comprehensive set of application interfaces and related options that support
a wide range of applications including wireless RS232/485 cable replacements, wireless sensor
networks, wireless alarm systems and industrial remote control applications. Recommended
configuration steps for each application interface are discussed in Sections 5.1 through 5.7 below.

5.1 Configuring the Serial Port

The default serial port configuration is 9.6 kbps, 8-bit data, no parity and 1 stop bit.

1. Configure the serial data rate as required from 1.2 to 250 kbps by setting the SerialRate
parameter in Bank 3.

2. Configure the parity and number of stop bits by setting the SerialParams parameter in Bank 3.

3. Enable/disable serial port hardware flow control as required by setting the GpioAlt parameter in
Bank 6. Hardware flow control is disabled by default, but is recommended when operating at
higher baud rates and/or sending large blocks of data.