Murata Electronics North America DNT90 User Manual

IC Radio Standards Specification: RSS-210

ACS Report Number: 10-0314.W06.11.A

Certification Exhibit

FCC ID: HSW-DNT90

IC: 4492A-DNT90

FCC Rule Part: 15.247

Manufacturer: RFM/Cirronet

Model: DNT90C, DNT90P

Manual

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

DNT90 Series

900 MHz Spread Spectrum

Wireless Transceivers

Integration Guide

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Important Regulatory Information

RFM Product FCC ID: HSW-DNT90

IC 4492A-DNT90

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 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 in­structions, 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.

FCC Antenna Gain Restriction and MPE Statement:

The DNT90 has been designed to operate with any dipole antenna of up to 5.1 dBi of gain, or any Yagi of
up to 6.1 dBi gain.

The antenna(s) used for this transmitter must be installed to provide a separation distan ce of at least
20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or
transmitter.

Industry Canada Specific Statements:

The term “IC:” before the radio certification number only signifies that Industry Canada technical specifica­tions were met.

This Class B digital apparatus meets all requirements of the Canadian Interference Causing Equipment
Regulations. 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.

Cet appareillage numérique de la classe B répond à toutes les exigences de l'interférence canadienne
causant des règlements d'équipement. L'opération est sujette aux deux conditions suivantes: (1) ce dis­positif peut ne pas causer l'interférence nocive, et (2) ce dispositif doit accepter n'importe quelle interfé­rence reçue, y compris l'interférence qui peut causer l'opération peu désirée.

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IC RSS-210 Detachable Antenna Gain Restriction:

This device has been designed to operate with the antennas listed below, and having a maximum gain of

6.1 dB. Antennas not included in this list or having a gain greater than 6.1 dB are strictly prohibited for
use with this device. The required antenna impedance is 50 ohms:

RFM RWA092R Omnidirectional Dipole Antenna, 2 dBi
RFM OMNI095 Omnidirectional Dipole Antenna, 5 dBi
RFM YAGI099 Directional Antenna, 6.1 dBi

To reduce potential radio interference to other users, the antenna type and its gain should be so ch osen
that the equivalent isotropically radiated power (e.i.r.p.) is not more than that permitted for successful
communication.

See Section 6.8 of this manual for regulatory notices and labeling requirements. Changes or modifica­tions to a DNT90 not expressly approved by RFM may void the user’s authority to operate the module.

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Table of Contents

1.0 DNT90 Introduction .......................................................................................................................... 5

1.1 Why Spread Spectrum? ............................................................................................................ 5

1.2 Frequency Hopping versus Direct Sequence ............................................................................ 6

2.0 DNT90 System Overview ................................................................................................................. 7

2.1 Point-to-Point Systems .............................................................................................................. 7

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

2.3 Store-and-Forward Systems ...................................................................................................... 8

2.4 RF Channel Access ................................................................................................................... 9

2.5 DNT90 Addressing .................................................................................................................... 9

2.6 Network Linking and Slot Registration .................................................................................... 10

2.7 Transparent and Protocol-formatted Serial Data ..................................................................... 10

3.0 DNT90 Application Interfaces ........................................................................................................ 11

3.1 Serial Port ................................................................................................................................ 11

3.2 SPI Port ................................................................................................................................... 11

3.3 Digital I/O ................................................................................................................................. 14

3.4 Analog I/O ................................................................................................................................ 14

3.5 I/O Event Reporting and I/O Binding ....................................................................................... 14

4.0 DNT90 System Configuration ........................................................................................................ 15

4.1 Configuration Parameters ........................................................................................................ 15

4.2 Configuring a Basic Point-to-Point System ............................................................................. 15

4.3 Configuring a Custom Point-to-Point or Point-to-Multipoint System ....................................... 16

4.4 Configuring a Store-and-Forward System ............................................................................... 17

4.5 Coordinating Slot Sizes and Hop Duration .............................................................................. 18

5.0 DNT90 Application Interface Configuration.................................................................................... 19

5.1 Configuring the Serial Port ...................................................................................................... 20

5.2 Configuring the SPI Port .......................................................................................................... 20

5.3 Configuring Digital I/O ............................................................................................................. 20

5.4 Configuring Analog I/O ............................................................................................................ 21

5.5 Configuring I/O Event Reporting and I/O Binding .................................................................... 21

5.6 Configuring Sleep Mode .......................................................................................................... 21

6.0 DNT90 Hardware ........................................................................................................................... 23

6.1 Electrical Specifications ........................................................................................................... 24

6.2 Module Pin Out ........................................................................................................

6.3 Antenna Connector .................................................................................................................. 26

6.4 Power Supply and Input Voltages ........................................................................................... 27

6.5 ESD and Transient Protection ................................................................................................. 27

6.6 Interfacing to 5 V Logic Systems ............................................................................................. 27

6.7 Mounting and Enclosures ........................................................................................................ 27

6.8 Labeling and Notices ............................................................................................................... 28

7.0 DNT90 Protocol-formatted Messages ............................................................................................ 29

7.1 Protocol Formats ..................................................................................................................... 29

7.2 Message Types ....................................................................................................................... 29

7.3 Message Format Details .......................................................................................................... 30

................ 25

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7.4 Configuration Parameter Registers ......................................................................................... 37

7.4.1 Bank 0 - Transceiver Setup .............................................................................................. 37

7.4.2 Bank 1 - System Settings .................................................................................................. 39

7.4.3 Bank 2 - Status Parameters .............................................................................................. 40

7.4.4 Bank 3 - Serial and SPI Settings ....................................................................................... 42

7.4.5 Bank 4 - Host Protocol Settings ........................................................................................ 43

7.4.6 Bank 5 - I/O Parameters ................................................................................................... 44

7.4.7 Bank 6 - I/O Settings ......................................................................................................... 45

7.4.8 Bank FF - Special Functions ............................................................................................. 48

7.5 Protocol-formatted Message Examples .................................................................................. 49

7.5. 1 Data Message ................................................................................................................... 49

7.5.2 Configuration Message ..................................................................................................... 49

7.5.3 Event Message ................................................................................................................. 50

7.5.4 Sensor Message ............................................................................................................... 50

8.0 DNT90DK Developer’s Kit ............................................................................................................. 52

8.1 DNT90DK Kit Contents ......................................................................................................... TBD

8.2 Additional Items Needed ...................................................................................................... TBD

8.3 Developer’s Kit Default Operating Configuration .................................................................. TBD

8.4 Developer’s Kit Hardware Assembly .................................................................................... TBD

8.5 DNT90 Utility Program .......................................................................................................... TBD

8.6 Initial Kit Operation ............................................................................................................... TBD

8.6.1 Serial Communication and Radio Configuration ............................................................ TBD

8.7 DNT90 Wizard Program ....................................................................................................... TBD

8.8 DNT90 Interface Board Features ......................................................................................... TBD

9.0 Troubleshooting .......................................................................................................................... TBD

9.1 Diagnostic Port Commands .................................................................................................. TBD

10.0 Appendices ................................................................................................................................. TBD

10.1 Ordering Information ............................................................................................................. TBD

10.2 Technical Support ................................................................................................................. TBD

10.3 DNT90 Mechanical Specifications ........................................................................................ TBD

10.4 DNT90 Development Board Schematic ............................................................................... TBD

11.0 Warranty ...................................................................................................................................... TBD

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1.0 DNT90 Introduction

DNT90 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 the US, Canada, South America, Israel, Austral­ia and New Zealand. The DNT90 supports serial data rates for host communications from 1.2 to

230.4 kbps, plus three SPI data rates from 125 to 500 kbps. On-board data buffering plus an error­correcting radio protocol provide smooth data flow and simplify the task of integration with existing appli­cations. Key DNT90 features include:

 Multipath fading resistant frequency hopping

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

 Ad Hoc TDMA operating mode supports a

large number of remotes with low latency for
burst data streaming

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

and store-and-forward networks

 FCC 15.247 and IC RSS-210 certified for

license-free operation

 5 mile plus range with omnidirectional anten-

nas (antenna height dependent)

 Transparent ARQ protocol with data

buffering ensures data integrity

 AES encryption provides protection from ea-

vesdropping

 Nonvolatile memory stores DNT90 configura-

tion when powered off

 Selectable +16 or +22 dBm transmit power

levels

 Simple interface handles both data and con-

trol at up to 230.4 kbps on the serial port or
500 kbps on the SPI port

 Analog and Digital I/O simplifies wireless

sensing

 Automatic event reporting mode for I/O

simplifies application development

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.

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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 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

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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 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 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 DNT90 System Overview

A DNT90 radio can be configured to operate in one of three modes - base, remote or router. A base con­trols a DNT90 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 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 by the router rather than being repeated.

2.1 Point-to-Point Systems

A DNT90 system contains at least one network. The simplest DNT90 topology 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. Point­to-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 [replace with DNT90 graphics]

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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,

DNT90 technology also allows for peer-to-peer communication from one remote to another.

Figure 2.2.1 [replace with DNT90 graphics]

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 can be

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 every hour or so.

Figure 2.3.1 [replace with DNT90 graphics]

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2.4 RF Channel Access

The time a DNT90 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 orga-

nized as a time division multiple access (TDMA) frame. A DNT90 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 addressed to one or more child radios.

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

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

C o n t r o l

B a s e - M o d e

M e s s a g e s t o

N e t w o r k C h i l d r e n

B e a c o n

O p e n

S l o t

A s s i g n e d

S l o t

S l o t s

O p e n

S l o t

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 retransmit its data. During times when there are no open slots, a child radio
keeps its data queued and continues to look for an open slot in each beacon until at least one slot be-

comes available. The access method the DNT90 uses is referred to as Ad Hoc TDMA or hybrid
CSMA/TDMA.

2.5 DNT90 Addressing

Each DNT90 has a unique MAC address. The MAC address can be read or bar-code scanned from the

label on top of each radio. A DNT90 radio in any mode (base/router/remote) can be addressed using its
MAC address. A DNT90 base can be addressed using either its MAC address or address 0x000000. A
DNT90 can send a message to all other DNT90’s in its system by using the broadcast address
0xFFFFFF.

The base and all routers (parents) hold a base-mode network ID, which is transmitted in every beacon. All
routers and remotes hold a parent network ID and optionally an alternate parent network ID 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.

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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 DNT90 radios hold a system ID that can be used to distinguish systems that physically overlap. In a
DNT90 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 Pa-
rentMacAddress 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 DNT90 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 base-

mode beacon includes one of a number of cycled control parameters. The cycled parameters are col-

lected 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 DNT90 system.

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 (link lost).

2.7 Transparent and Protocol-formatted Serial Data

A DNT90 remote can directly input and output data bytes and data strings on its serial port. This is re-

ferred 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.

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Transparent data is routed using a remote transparent destination address. In a remote, this address de-

faults 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.

3.0 DNT90 Application Interfaces

A DNT90 module provides a variety of application interfaces including a serial port, 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 Port

The DNT90 serial port is a full-duplex UART interface with hardware flow control on two of the digital I/O
pins as a default feature. One digital I/O pin can also be configure as an RS485 enable function. The
serial port can be configured with baud rates from 1.2 to 230.4 kbps, with 9.6 kbps the default baud rate.
The DNT90 serial port transmits/receives 8-bit data with a choice of even/odd/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 serial port, and Section 7.4.4 for detailed information on serial port configuration parameters.

3.2 SPI Port

The DNT90 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 configure 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

M I S O

M O S I

S C L K

/ S S

D N T 9 0P e r i p h e r a l

Figure 3.2.1

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The DNT90 SPI port can run at three clock rates in master mode - 125, 250 or 500 kbps. There are two

message sources available to a DNT90 SPI master, a protocol-formatted RxData message, or a stored

command. The DNT90 master will clock a message from either source into its slave and return the bytes

clocked out as a protocol-formatted TxData message. The DNT90 event timer triggers sending the stored

command to the DNT90’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.

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 I S O

M O S I

S P I B i t C l o c k

C o m m a n d t o S l a v e

D a t a f r o m S l a v e

Figure 3.2.2

In SPI slave mode, the host can stream data into DNT90 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 DNT90 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

M I S O

M O S I

S C L K

/ S S

/ H O S T _ R T S

/ H O S T _ C T S

D A V

D N T 9 0H o s t

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

S P I B i t C l o c k

M e s s a g e t o D N T 9 0

Figure 3.2.4

The host should use the following steps to fetch data from a DNT90 SPI slave, as show in Figure 3.2.5:

1. The host sets the /HOST_RTS signal high to allow the DNT90 to signal data available.

2. The DNT90 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 DNT90 to signal DAV the next time it

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.

has data.

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

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

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 s a g e

Figure 3.2.5

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3.3 Digital I/O

The DNT90’s six digital (state) I/O ports are labeled GPIO0 through GPIO5. GPIO5 defaults to /HOST_
RTS and GPIO4 defaults to /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). Ex­cept in SPI slave mode, GPIO0 through GPIO3 and optionally GPIO4 and 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 DNT90’s three ADC inputs are labeled ADC0 through ADC2. The ADCs can be disabled if unused to
reduce current consumption. ADC measurements are made with 12-bit resolution. There are three op­tions for the ADC full-scale reference:

1. The DNT90 regulated buss voltage divided by 1.6 or about 2.06 V

2. An internal band-gap reference voltage, 1.00 V nominal

3. A voltage supplied to the DNT90’s ADC_EXT_REF input pin, 2.70 V maximum. If no connection
is made to this pin, a voltage equal to about 1/2 the buss voltage will be present.

The three ADCs are read each ADC sample interval, which is configurable. High and low measurement
thresholds can be set for each ADC input to trigger I/O event reporting messages.

The DNT90’s two DAC outputs are labeled DAC0 and DAC1. The DACs can be disabled if unused to re­duce current consumption. The DAC settings have 12-bit resolution. There are three options for the DAC
full-scale reference:

1. The DNT90 regulated buss voltage, about 3.3 V

2. An internal band-gap reference voltage, 1.00 V nominal

3. A voltage supplied to the DNT90’s ADC_EXT_REF input pin, 2.70 V maximum. If no connection
is made to this pin, a voltage equal to about 1/2 the buss voltage 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 DNT90’s I/O event reporting function can generate a protocol-formatted RxEvent message when

triggered by one of the following I/O events:

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- 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
DNT90, 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 analog signals from one location to another. Note that
I/O binding cannot be used in a DNT90 when SPI slave mode is enabled. 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.

4.0 DNT90 System Configuration

DNT90 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 DNT90 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 mod-

ule’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 DNT90 system, net­work or application interface.

4.2 Configuring a Basic Point-to-Point System

A basic DNT90 point-to-point systems is suitable for many serial data applications. The default confi­guration of a DNT90 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.

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2. Set the MemorySave parameter in Bank 0xFF to 0xD2, which will save the DeviceMode parame-

ter to EEPROM and reset the module, enabling base operation.

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

4.3 Configuring a Custom Point-to-Point or Point-to-Multipoint System

To configure a customized point-to-point system or a point-to-multipoint system, RFM recommends the
following configuration sequence:

1. Configure one of the modules as a base by setting the DeviceMode parameter in Bank 0 to 0x01.

2. Set the 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 Bank 0).

4. Set the transmitter power level as needed in all radios by setting the TxPower parameter in

Bank 0 (the default is 40 mW).

5. Configure the system ID in all radios by setting the SystemID parameter in Bank 0 (the default 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 in the

remotes.

8. For a point-to-multipoint system, 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.

9. If using transparent serial mode in the system:

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

Bank 0, in each remote (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 des-

tination 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 pa-

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

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. Set the maximum number of messages that can be sent in a frame in each system radio. The pa-

rameter that controls this number is MaxDataPackets in Bank 4 (the default is 8 messages ).

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11. Load the required base slot size into the BaseSlotSize parameter, Bank 1, in the base. The de-

fault is 40 bytes. See Section 4.5 below.

12. Configure the number of slots per frame on the base by setting the NumSlots parameter (the de-

fault is 3 slots). See Section 4.5 below.

13. Set the required hop duration on the base. The HopDuration parameter in Bank 0 controls hop

duration. The default is 20 ms. See Section 4.5 below.

14. Configure the slot lease on the base by setting the SlotLease parameter. The default is 4 hops.

15. Set the heartbeat interval as required in each system radio. The parameter that controls heart-

beats is the HeartBeatIntrvl in Bank 0. The default is 20 seconds/heartbeat.

16. Enable message ACKs where required by setting the AckEnable parameter in Bank 0 to 1. The

default is ACKs disabled.

17. Set the message retry limit on the base with the ArqAttemptLimit parameter in Bank 1. The de-

fault value is 4 retries.

18. Configure the link drop threshold on the base by setting the LinkDropThreshold in Bank 1 (the de-

fault is 10 hops).

19. Set the point-to-point reply timeout on the base in the P2PReplyTimeout parameter in Bank 1.

The default is 16 hops.

20. Configure the registration timeout on the base by setting the RegistryTimeout parameter in
Bank 1 (the default timeout is 50 hops).

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

4.4 Configuring a Store-and-Forward System

The following additional parameters must be set to configure a DNT90 store-and-forward system:

1. Configure the DNT90 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.

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 the system topology manually, 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 rou-

ter and remote to automatically link to a parent, causing the system to form

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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 optionally the AltParentNwkID parameters to specific val-

ues 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 unnecessary number 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.

4.5 Coordinating Slot Sizes and Hop Duration

The base slot size (BSS) is 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 DNT90
system is configured for one slot. Adding additional slots reduces the maximum BSS by three bytes per
slot. The base transmit buffer is set nine bytes larger than the BSS, to a maximum of 114 bytes. The base

can potentially send more than one message per beacon. Each message in the transmit 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
TX buffer = 90 + 9 = 99
3 headers = 3*9 = 27
net for payload = 99 - 27 = 72

The BSS must be large enough to accommodate all protocol-formatted messages that may be sent over

the wireless link, as these messages must be sent in a single transmission.

The size of all (child) slots in a hop frame is the same, and is referred to as the remote slot size (RSS).
The RSS is calculated by all DNT90s in a system. The slot size depends on the current values of the fol-

lowing parameters:

- base slot size

- hop duration

The user must be able to configure the system so that the RSS will accommodate all protocol-formatted
message that may be sent over the wireless link. 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:

-number of slots in a frame

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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:

A B C 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 1 20 20 =A3*(80*C3+2440) + 80*B3 + 3280

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

For transparent serial port operation, the BSS and RSS must be large enough to accommodate all mes­sage bytes that can accumulate between transmissions. As discussed above, the number of message

bytes is controlled by the MinPacketLength parameter setting. 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
all configuration commands, replies, event messages and announce messages, a 20 byte minimum slot
size is required.

5.0 DNT90 Application Interface Configuration

DNT90 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.

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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 230.4 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 handshaking as required by setting the GpioAlt parameter in Bank 6.

Handshaking is enabled by default, and is recommended for data rates 9.6 kbps and higher.

5.2 Configuring the SPI Port

1. Enable either SPI master mode or SPI slave mode by setting the SpiMode parameter in Bank 3.

Note that SPI slave mode disables serial port operation.

2. If using SPI master mode:

a. Select the SPI clock rate by setting the SpiRateSel parameter in Bank 3 (default

is 125 kbps)

b. Set the SPI master command string and string length by setting the SpiMasterCmdStr

and SpiMasterCmdLen parameters respectively in Bank 3.

3. Configure the edge trigger direction, bit-sampling edge and bit-order options by setting the

SpiOptions parameter in Bank 3.

5.3 Configuring Digital I/O

1. GPIO2 through GPIO 5 have configurable alternate functions as discussed in Section 7.4.7. Se­lect either digital (state) functionality or alternate functionality for each of these pins by setting the

GpioAlt parameter in Bank 6. Note that selecting SPI slave mode overrides the GpioAlt parameter

setting for GPIO3 though GPIO5.

2. Configure the direction of each GPIO pin as needed by setting the GpioDir parameter in Bank 6

(the default is all inputs).

3. Configure the direction of each GPIO pin for sleep mode as needed by setting the GpioSleepDir

parameter in Bank 6 (the default is all inputs).

4. Set the initial state (power on) of all GPIO pins configured as outputs by setting the GpioInit pa-

rameter in Bank 6 (the default is all logic low).

5. Set the state of all GPIO pins configured as outputs in sleep mode by setting the GpioSleepState

parameter in Bank 6 (the default is all logic low).

6. GPIO0 through GPIO3 can trigger I/O event reporting when functioning as digital inputs. Enable

event report triggering and optional sleep hold-off for these pins by setting the GpioEdgeTrigger

parameter in Bank 6.

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5.4 Configuring Analog I/O

1. Select the ADC full scale reference by setting the AdcReference parameter in Bank 6. This set-

ting applies to all ADC channels. The default is the ADC_EXT_REF input. If ADC operation is not
needed, setting this parameter to 0x03 disables ADC operation, reducing current consumption.

2. Configure the ADC measurement interval by setting the AdcSampleIntvl parameter. The default is

10 ms, and applies to all ADC channels.

3. Measurements on each ADC input can be compared to high/low threshold values, triggering an
I/O event report if the measurements go above/below the respective thresholds. The thresholds

for each ADC channel are set by loading the AdcXThresholdLo and AdcXThresholdHi, where X

refers to the ADC channel designator, 0 through 2.

4. Select the DAC full scale reference by setting the DacReference parameter in Bank 6. This set-

ting applies to both DAC channels. The default is the ADC_EXT_REF input. If DAC operation is
not needed, setting this parameter to 0x03 will disable DAC operation, reducing current consump­tion.

5. Configure the initial (power on) output level for DAC0 and DAC1 by loading the initial settings in

the Dac0Init and Dac1Init parameters respectively.

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

1. Select the analog, digital and timing events that will trigger an I/O event report by setting the

respective bits in the IoReportTrigger parameter in Bank 6. The default is no triggers set.

2. Configure the trigger behavior bits in the GpioEdgeTrigger parameter, Bank 6, for each GPIO

input selected to generate an I/O event report.

3. For each ADC channel selected to generate an I/O event, set the high and low measurement

threshold values. The AdcThreshold parameters are in Bank 6 at register offsets 15, 17, 19, 21,

23 and 25.

4. If the periodic timer has been selected to generate an event report, load the required timer report

interval into the IoReportInterval parameter in Bank 6. The default timer interval is 30 seconds.

5. The ReportHoldoff parameter in Bank 6 sets the delay following an event to take ADC readings

for the I/O event report. The parameter scaling is in milliseconds, and the default is 0. Set this pa­rameter as required to avoid transient interference with the ADC measurements.

6. If I/O binding operation is desired, set the IoBindingEnable parameter in Bank 6 to 0x01. I/O

binding is disabled by default.

5.6 Configuring Sleep Mode

Sleep mode can be used in conjunction with I/O reporting to greatly extend battery life on DNT90 re-

motes. At least one I/O report trigger must be enabled to allow sleep mode to be used. Note that the
base and routers cannot be configured for sleep mode.

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1. Enable sleep mode as desired in each remote by setting the SleepModeEn parameter in Bank 0 to 1.

2. Configure the timeout for a remote to attempt to link to its parent when triggered awake. This is done

by setting the WakeLinkTimeout parameter in Bank 0. The default timeout is 5 seconds.

3. Configure the maximum time a remote in sleep mode will remain awake following linking, receiving an
ACK, processing a message addressed to it, or receiving a serial or SPI message by setting the

Wake-ResponseTime parameter. The default response time is 500 ms. Note that the setting of this
parameter is overridden by some GpioEdgeTrigger parameter settings.

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6.0 DNT90 Hardware

D N T 9 0 B l o c k D i a g r a m

+ 3 . 3 V

1

2

3

4

5

6

7

8

9

F i l t e r

1 0

1 1

1 2

1 3

F i l t e r

1 4

1 5

R e g

G N D

/ R E S E T

M i c r o c o n t r o l l e r

1 8 1 9 2 0 2 1 2 2 2 31 71 6 2 4 2 5 2 6

M I S O

A D C 0

M O S I

A D C 1

3 . 3 V _ O U T

S C L K

/ S S

A D C _ E X T _ R E F

2 7

2 8 2 9 3 0

R S V D

G N D

R S V D

R S V D

n S S _ C O N F I G

G N D

I R Q 0

I R Q 1 / D C L K

D A T A

P L L _ L O C K

S C K

S D I

S D O

n S S _ D A T A

T R C 1 0 3

S A W F i l t e r

a n d

P o w e r A m p

G N D

/ D C D

A C T

G P I O 0

R A D I O _ T X D

R A D I O _ R X D

/ H O S T _ C T S

/ H O S T _ R T S

D A C 0

G P I O 2

G P I O 1

D A V ( G P I O 3 )

D A C 1

V C C

G N D

Figure 6.0.1

The major components of the DNT90 include an RFM TRC103 900 MHz FHSS transceiver and a low cur­rent 8-bit microcontroller. The DNT90 operates in the 902 to 928 MHz ISM band. There are three selecta­ble hopping patterns providing compatibility with frequency allocations in the US, Canada, South America,
Israel, Australia and New Zealand. The DNT90 also has two selectable RF output power levels: +16 dBm
(40 mW) and +22 dBm (158 mW).

The DNT90 receiver is protected by a low-loss SAW filter, providing an excellent blend of receiver sensi­tivity and out-of-band interference rejection that is especially important in outdoor applications.

The DNT90 provides a variety of hardware interfaces. There are two serial ports plus one SPI port. Either
the primary serial port or the SPI port can be selected for data communications. The second serial port is
dedicated to diagnostics. The primary and diagnostic serial ports support most standard baud rates up to

230.4 kbps. The SPI port supports data rates up to 500 kbps. Also included are three 12-bit ADC inputs,

two 12-bit DAC outputs, and six general-purpose digital I/O ports. Two of the digital I/O ports support an
optional interrupt-from-sleep mode when configured as inputs. The radio is available in two mounting con­figurations. The DNT90C is designed for solder reflow mounting. The DNT90P is designed for plug-in
connector mounting.

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6.1 Specifications

Absolute Maximum Rating Value Units

Power Supply Input -0.5 to +6.5 V

All Input/Output Pins -0.5 to +3.3 V

Input Power to RFIO Port 0 dBm

Non-operating Ambient Temperature Range -40 to +85

Table 6.1.1

Operating Characteristic Sym Minimum Typical Maximum Units

Operating Frequency Range 902.76 927.24 MHz

Hop Dwell Time 8 100 ms

Number of RF Channels 25 52

Modulation FSK

RF Data Transmission Rate 100 kbps

Receiver Sensitivity, 10-5 BER -100 dBm

Transmitter RF Output Power Levels 40, 158 mW

Optimum Antenna Impedance 50 Ω

RF Connection U.FL Connector

Network Topologies

Point-to-Point, Point-to-Multipoint,

Store and Forward

Access Scheme Hybrid TDMA/CSMA

Number of Access Slots 1 8

ADC Input Range 0 2.5 V

ADC Input Resolution 12 bits

ADC Sample Rate 100 Hz

Signal Source Impedance for ADC Reading 10 KΩ

ADC External Reference Voltage Range 1.0 2.7 V

DAC Output Range 0 3.3 V

DAC Output Resolution 12 bits

Primary and Diagnostic Serial Port Baud Rates

1.2, 2.4, 4.8, 9.6, 19.2, 14.4 28.8, 38.4,

57.6, 115.2, 230.4

Serial Peripheral Interface Data Rate 125 250 500 kbps

Digital I/O:

Logic Low Input Level -0.5 0.8 V

Logic High Input Level 2.45 3.3 V

Logic Input Internal Pull-up Resistor 20 KΩ

Power Supply Voltage Range VCC +3.3 +5.5 Vdc

Power Supply Voltage Ripple 10 mV

Peak Transmit Mode Current, 158 mW Output 150 mA

Average Operating Receive Current:

Base, Continuous Data Stream 25 mA

Remote, Linked, No Data 12 mA

Remote, Continuous Data Stream 25 mA

Sleep Current 3 TBD µA

Operating Temperature Range -40 85

Operating Relative Humidity Range (non condensing) 10 90 %

Table 6.1.2

o

C

kbps

P-P

o

C

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6.2 Module Pin Out

Electrical connections to the DNT90C are made through the I/O pads and through the I/O pins on the
DNT90P. The hardware I/O functions are detailed in the table below:

Pin Name I/O Description

1 GND -

2

3

4 GPIO0 I/O

5 RADIO_TXD O

6 RADIO_RXD I

7

8

9 DAC0 O

10 GPIO2 I/O

11 GPIO1 I/O

12

13 DAC1 O

14 VCC I

15 GND -

16 GND -

17 /RESET I

18 ADC0 I

19 ADC1 I

20 MISO I/O

21 MOSI I/O

22 /SS I/O

23 SCLK I/O

/DCD

(DIAG_TX) O (O)

ACT

(DIAG_RX) O (I)

GPOI4

(/HOST_CTS) O (I/O)

GPIO5

(/HOST_RTS) I (I/O)

DAV

(GPIO3)

Power supply and signal ground. Connect to the host circuit board ground.

This pin’s default configuration is a “data carrier detect” output. On a base, this signal is asserted
when any valid packet is received, and is cleared if no packets are heard for the configured rou­ter/remote registration time-out interval. On a router or remote, this signal is asserted when the
radio obtains hopping pattern synchronization, and remains asserted until no beacons are heard
for 50 hops. Alternate pin function is the diagnostic serial port output.

Data activity output. On a base, this signal blinks when a valid packet is received. On a remote,
this signal blinks when a packet is transmitted. On a router, this signal blinks when a valid up­stream packet is received or a downstream packet is transmitted. Alternate pin function is the di­agnostic serial port input.

Configurable digital I/O port 0. When configured as an input, an internal pull-up resistor can be
selected and direct interrupt from sleep can be invoked. When configured as an output, the power­on state is configurable. In sleep mode the pin direction, input pull-up selection or output state are
also separately configurable.

Serial data output from the radio.

Serial data input to the radio.

GPIO4 with the same configuration options as GPIO2. Alternate pin function is UART/SPI flow
control output. The module sets this line low when it is ready to accept data from the host on the
RADIO_RXD or MOSI input. When the line goes high, the host must stop sending data.

GPIO5 with the same configuration options as GPIO2. Alternate pin function is UART/SPI flow
control input. The host sets this line low to allow data to flow from the module on the RADIO_TXD
pin. When the host sets this line high, the module will stop sending data to the host.

12-bit DAC 0 output with an internal first-order lowpass filter with a 159 Hz 3 dB bandwidth, 10K
output resistance. DAC full scale output can be referenced to the voltage at pin 25, the internal 1 V
band-gap reference, or the 3.3 V regulated module bus voltage.

Configurable digital I/O port 2. Same configuration options as GPIO0 except interrupt from sleep is
only tested at the sleep mode ADC sampling interval.

Configurable digital I/O port 1. Same configuration options as GPIO0.

When SPI slave mode operation is enabled, a logic high on this pin indicates when data is availa-

O

ble to be clocked out by the SPI master. Alternate pin function is GPIO3 with the same configura-

I/O

tion options as GPIO2.

12-bit DAC 1 output. Same specifications and configuration options as DAC0.

Power supply input, +3.3 to +5.5 Vdc.

Power supply and signal ground. Connect to the host circuit board ground.

Power supply and signal ground. Connect to the host circuit board ground.

Active low module hardware reset.

12-bit ADC input 0. Full-scale reading can be referenced to Pin 25 for ratiometric measurements.
For absolute measurements, the ADC can use either an internal 1 V band-gap reference, the regu­lated buss voltage divided by 1.6 (about 2.06 V), or an external voltage applied to Pin 25. The ADC
full-scale reading is equal to 4095 - calibration offset or nominally 2.5 V when referenced to a 2.7 V
input on Pin 27.

12-bit ADC input 1. Same configuration options as ADC0.

This pin is the SPI master mode input or slave mode output.

This pin is the SPI master mode output or slave mode input.

SPI active low slave select. This pin is an output when the module is operating as a master, and an
input when it is operating as a slave.

SPI clock signal. This pin is an output when operating as a master, and an input when operating as
a slave.

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DNT90 Integration Guide - 10/25/10