FCC ID: HSW-DNT500P Modular 900 MHz Transceiver

 

DNT500 Series 900 MHz Spread Spectrum Wireless Industrial Transceivers Integration Guide 3079 Premiere Pkwy Ste 140 Norcross, Georgia 30097 www.rfm.com

+1 (678) 684-2000 Important Regulatory Information RFM Product FCC ID: HSW-DNT500P IC 4492A-DNT500P Note: This unit 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 when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communica-

tions. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at their expense. The DNT500 has been designed to operate with the RWA092R 2 dBi reverse-pin (polarity) SMA sleeved dipole antenna (U.FL female to reverse-pin SMA female adaptor or equivalent required). See section 3.10 of this manual for regulatory notices and labeling requirements. Changes or modifica-

tions not expressly approved by RFM may void the users authority to operate the module. TABLE OF CONTENTS 1. INTRODUCTION................................................................................................................ 1 1.1 Why Spread Spectrum?................................................................................................... 1 Frequency Hopping versus Direct Sequence .................................................................. 2 1.2 2. 2.1 2.2 2.3 2.4 2.5 2.6 2.7 DNT500 RADIO OPERATION .......................................................................................... 4 Network Synchronization and Registration .................................................................... 4 Transparent and Protocol Serial Port Modes................................................................... 4 RF Data Communications ............................................................................................... 5 RF Transmission Error Control....................................................................................... 5 Network Configurations.................................................................................................. 6 2.5.1 Point-to-Point Network Operation .......................................................................... 6 2.5.2 Point-to-Multipoint Network Operation.................................................................. 7 Full-Duplex Serial Data Communications ...................................................................... 7 Channel Access ............................................................................................................... 7 2.7.1 CSMA Modes.......................................................................................................... 8 2.7.2 TDMA Modes ......................................................................................................... 9 2.7.3 Network Configuration Planning .......................................................................... 10 2.7.4 Serial Port Operation............................................................................................. 12 2.7.5 Sleep Mode............................................................................................................ 13 3. DNT500 HARDWARE...................................................................................................... 14 3.1 Specifications ................................................................................................................ 15 3.2 Module Interface ........................................................................................................... 16 3.3 Input Voltages ............................................................................................................... 17 ESD and Transient Protection....................................................................................... 17 3.4 Interfacing to 5 V Logic Systems.................................................................................. 18 3.5 3.6 Power-On Reset Requirements ..................................................................................... 18 3.7 Analog RSSI Output...................................................................................................... 18 3.8 Mounting and Enclosures.............................................................................................. 18 3.9 Connecting Antennas .................................................................................................... 19 3.10 Labeling and Notices..................................................................................................... 19 4. 4.1 4.2 PROTOCOL MESSAGES ................................................................................................. 20 Protocol Message Formats ............................................................................................ 20 4.1.1 Serial message types.............................................................................................. 20 4.1.2 Escape sequence.................................................................................................... 22 4.1.3 CFG select pin....................................................................................................... 23 4.1.4 Flow control .......................................................................................................... 23 4.1.5 Protocol mode data message example................................................................... 23 Configuration Registers................................................................................................. 23 4.2.1 Bank 0 - Transceiver Setup ................................................................................... 24 4.2.2 Bank 1 - System Settings ...................................................................................... 26 4.2.3 Bank 2 - Status Registers (read only)................................................................... 28 4.2.4 Bank 3 - Serial...................................................................................................... 30 4.2.5 Bank 4 - Host Protocol Settings ........................................................................... 31 4.2.6 Bank 5 - I/O Peripheral Registers ........................................................................ 33 4.2.7 Bank 6 - I/O setup ................................................................................................ 33 4.2.8 Bank FF - Special function................................................................................... 36 4.2.9 Protocol Mode Configuration/Sensor Message Examples.................................... 36 4.2.10 Protocol Mode Event Message Examples............................................................. 37 5. 5.1 5.2 5.3 5.4 5.5 5.6 DNT500 DEVELOPERS KIT .......................................................................................... 38 DNT500DK Kit Contents.............................................................................................. 38 Additional Items Needed............................................................................................... 38 Developers Kit Default Operating Configuration........................................................ 39 Development Kit Hardware Assembly ......................................................................... 39 DNT500 Wizard Utility Program.................................................................................. 41 DNT500 Interface Board Features ................................................................................ 47 6. 7. 8. 8.1 8.2 8.3 Demonstration Procedure ................................................................................................... 50 Troubleshooting.................................................................................................................. 51 APPENDICES.................................................................................................................... 52 Ordering Information .................................................................................................... 52 Technical Support ......................................................................................................... 52 DNT500 Mechanical Specifications ............................................................................. 53 9. Warranty............................................................................................................................. 55 1. INTRODUCTION DNT500 The DNT500 series transceivers provide highly reliable wireless connectivity for either point-to-point or point-to-multipoint 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, Australia and New Zealand. The DNT500 supports all standard serial data rates for host communications from 1.2 to 460.8 kb/s. On-board data buffering and an error-correcting air protocol provide smooth data flow and sim-

plify the task of integration with existing applications. Key DNT500 features include:

- Multipath fading impervious fre-

quency hopping technology with up to 50 frequency channels

(902 to 928 MHz).

- Supports point-to-point or multi-

point applications.

- Meets FCC rules 15.247 for li-

cense-free operation.

- 20 mile plus range with omni-

directional antennas.

- Transparent ARQ protocol with buffering ensures data integrity.

- Selectable 0, 10, 19, 24, 27 or 28 dBm transmit power with a firmware interlock of 19 dBm maxi-

mum for 500 kb/s operation.

- Built-in data scrambling reduces possibility of eavesdropping.

- Nonvolatile memory stores configu-

ration when powered off.

- Dynamic TDMA slot assignment that maximizes throughput.

- Simple serial interface handles both data and control at up to 460.8 kb/s. 1.1 Why Spread Spectrum?

A radio transmission 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 through a phenomenon known as multi-

path fading. Multipath fading results when two or more reflected rays of the transmit-

ted signal arrive at the receiving antenna with opposing phases, thereby partially or completely canceling the signal. This is a problem particularly prevalent in indoor in-

stallations. In the frequency domain, a multipath fade can be described as a fre-

quency-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, mul-

tipath fades will typically occupy 1% - 2% of the band. This means that from a prob-

abilistic viewpoint, a conventional radio system faces a 1% - 2% chance of signal im-

pairment at any given time due to multipath. Spread spectrum reduces the vulnerability of a radio system to interference from both jammers and multipath fading by distributing the transmitted signal over a larger re-

gion of the frequency band than would otherwise be necessary to send the informa-

tion. This allows the signal to be reconstructed even though part of it may be lost or corrupted in transit. 2008 by RF Monolithics, Inc. 1 M-0500-0000 Rev D DNT500 Figure1 Narrowband vs. spread spectrum in the presence of interference 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 gener-

ally 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 pat-

tern. 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 narrowband 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. Figure 2 Forms of spread spectrum 2008 by RF Monolithics, Inc. 2 M-0500-0000 Rev D DNT500 One disadvantage of direct sequence systems is that due to spectrum constraints and the design difficulties of broadband receivers, they generally employ only a minimal amount of spreading (typically 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 probing the entire band if necessary to find a channel free of interference. Essentially, this means that a FHSS system will degrade gracefully as the channel 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 tend to offer few non-overlapping channels, whereas multiple hoppers may interleave with less interference. Frequency hopping does carry some disadvantage in that as the transmitter cycles through the hopping pattern it is nearly certain to visit a few blocked channels where no data can be sent. If these channels are the same from trip to trip, they can be memorized and avoided. Unfortunately, this is generally not the case, as it may take several seconds to completely cover the hop sequence during which time the multipath delay profile may have changed substantially. To ensure seamless operation throughout these outages, a hopping radio must be capable of buffering its data until a clear channel can be found. A second consideration of fre-

quency hopping systems is 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 hop-

ping systems generally feature greater coverage and channel utilization than compa-

rable 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. DNT500 series modules achieve regulatory certification under FHSS rules at air data rates of 38.4, 115.2 and 200 kb/s. At 500 kb/s, the DNT500 series modules achieve regulatory certification under digital modulation or DTS rules. At 500 kb/s DNT500 series modules still employ frequency hopping to mitigate the effects of in-

terference and multipath fading, but hop on fewer, more widely spaced frequencies than at lower data rates. 2008 by RF Monolithics, Inc. 3 M-0500-0000 Rev D DNT500 2. DNT500 RADIO OPERATION 2.1 Network Synchronization and Registration As discussed above, frequency hopping radios such as the DNT500 periodically change the frequency at which they transmit. In order for the other radios in the network to re-

ceive the transmission, they must be listening to the frequency over which the current transmission is being sent. To do this, all the radios in the network must be synchronized and must be set to the same hopping pattern. In point-to-point or point-to-multipoint networks, one radio module is designated as the base station. All other radios are designated remotes. One of the responsibilities of the base station is to transmit a synchronization signal to the remotes to allow them to syn-

chronize with the base station. Since the remotes know the hopping pattern, once they are synchronized with the base station, they know which frequency to hop to and when. Every time the base station hops to a different frequency, it immediately transmits a syn-

chronizing signal. When a remote is powered on, it rapidly scans the frequency band for the synchronizing signal. Since the base station is transmitting up to 50 frequencies and the remote is scan-

ning up to 50 frequencies, it can take several seconds for a remote to synchronize with the base station. Once a remote has synchronized with the base station, it will request registration informa-

tion to allow it to join the network. Registration can be handled automatically by the base station, or it can be controlled by allowing the base station host application to authenti-

cate the remote for registration. When a remote is registered, it receives several network parameters from the base station, including HopDuration, Nwk_ID, FrequencyBand and Nwk_Key (see Section 5.2 for parameter details). Note that if a registration parameter is changed at the base station, it will update the parameter in the remotes over the air. Among other things, registration allows the tracking of remotes entering and leaving a network, up to a limit of 255 remotes. The base station builds a table of serial numbers of registered remotes using their three-byte serial numbers (MAC addresses). To detect if a remote has gone offline or out of range, the registration is leased must be renewed once every 250 hops. Any transmission from a remote running on a leased registration will renew its lease with the base station. 2.2 Transparent and Protocol Serial Port Modes DNT500 radios can work in two serial port data modes: transparent and packet protocol. Transparent formatting is simply the raw user data. Packet protocol formatting uses a framing character, length byte, addressing, command bytes, etc. Transparent mode opera-

tion is especially useful in point-to-point systems that act as simple cable replacements. In point-to-multipoint systems where the base station needs to send data specifically to each remote, protocol formatting must be used. Protocol formatting is also required for configuration commands and responses, and sensor I/O commands and responses. Proto-

col formatting details are covered in Section 5. 2008 by RF Monolithics, Inc. 4 M-0500-0000 Rev D DNT500 The DNT500 provides two ways to switch between transparent and protocol modes. If CFG input Pin 18 on the DNT500 is switched from logic high to low, protocol mode is invoked. Or if the ASCII escape sequence DNT500 is sent (without quotation marks) to the primary serial input following at least a 20 ms pause in data flow, the DNT500 will switch to the protocol mode. When input Pin 18 is switched from logic low to high, or an ExitProtocolMode command is sent to the primary serial input, the DNT500 will switch to transparent operation. Note that if the escape sequence is used to switch to protocol mode, the sequence will be transmitted before protocol mode is invoked. When operating in transparent mode, two configuration parameters control when a DNT500 radio will send the data in its transmit buffer. The MinPacketLength parameter sets the minimum number of bytes that must be present in the transmit buffer to trigger a transmission. The TxTimeout parameter sets the maximum time data in the transmit buffer will be held before transmitting it, even if the number of data bytes is less than MinPacketLength. The default value for both the MinPacketLength and the TxTimeout parameters is zero, so that any bytes that arrive in the DNT500 transmit buffer will be sent on the next hop. As discussed in Section 2.7.3, it is useful to set these parameters to non-zero values in point-to-multipoint systems where some or all the remotes are in transparent mode. 2.3 RF Data Communications At the beginning of each hop, the base station transmits a synchronizing signal. After the synchronizing signal has been sent, the base will transmit any user data in its transmit buffer, unless in transparent mode the MinPacketLength and/or TxTimeout parameters have been set to non-zero. The maximum amount of user data that the base station can transmit per hop is limited by the BaseSlotSize parameter, which has a maximum value of 232 bytes. If there is no user data or reception acknowledgements (ACKs) to be sent on a hop, the base station will only transmit the synchronization signal. The operation for remotes is similar to the base station, but without the synchronizing signal. The RemoteSlotSize parameter sets the maximum number of user bytes a remote can transmit on one hop, up to a limit of 243 bytes per hop. The RemoteSlotSize must be coordinated with the HopDuration and BaseSlotSize parameters and the number of regis-

tered remotes, as discussed in Section 2.5.3. The MinPacketLength and TxTimeout pa-

rameters operate in a remote in the same manner as in the base station. 2.4 RF Transmission Error Control The DNT500 supports two error control modes: redundant transmissions and automatic transmission repeats (ARQ). In both modes, the radio will detect and discard any dupli-

cates of messages it receives so that the host application will only receive one copy of a given packet. Packet IDs are included in each transmission to allow recipients to identify if the packet is new or has been received before. In the redundant transmission mode, packets are repeated a fixed number of times with-

out any acknowledgement (ACK) from the recipient. This error control method is useful in latency-critical applications such as voice, video and real-time telemetry, where only a 2008 by RF Monolithics, Inc. 5 M-0500-0000 Rev D DNT500 few transmission repeats can be made before the current data is replaced with new data. It is wasteful of bandwidth to send ACKs in these types of applications. Redundant trans-

missions are also used where messages are broadcast to multiple recipients and it is not practical to receive ACKs from each one. In ARQ mode, a packet is sent and an acknowledgement is expected on the next hop. If an acknowledgement is not received, the packet is transmitted again on the next available hop until either an ACK is received or the maximum number of attempts is exhausted. If the AttemptLimit parameter is set to its maximum value, a packet transmission will be re-

tried without limit until the packet is acknowledged. This is useful in some point-to-point cable replacement applications where it is important that data truly be 100% error-free, even if the destination remote goes out of range temporarily. 2.5 Network Configurations The DNT500 supports two network configurations: point-to-point and point-to-

multipoint. In a point-to-point network, one radio is set up as the base station and the other radio is set up as a remote. In a point-to-multipoint network, a star topology is used with the radio set up as a base station acting as the central communications point and all other radios in the network set up as remotes. In this configuration, all communications take place between the base station and any one of the remotes. Remotes cannot commu-

nicate directly with each other. It should be noted that point-to-point operation is a subset of the point-to-multipoint operation, so there is no need to specify one or the other. 2.5.1 Point-to-Point Network Operation Most point-to-point networks act as serial cable replacements and both the base station and the remote use transparent mode. Unless the MinPacketLength and TxTimeout pa-

rameters have been set to non-zero, the base station will send the data in its transmit buffer on each hop, up to the limit set by the BaseSlotSize parameter, less ACK bytes. If the base station is buffering more data than can be sent on one hop, the remaining data will be sent on subsequent hops. The base station adds the address of the remote, a packet sequence number and error checking bytes to the data when it is transmitted. These addi-

tional bytes are not output at the remote in transparent mode. The sequence number is used in acknowledging successful transmissions and in retransmitting corrupted transmis-

sions. A two-byte CRC and a one-byte checksum allows a received transmission to be checked for errors. When a transmission is received by the remote, it will be acknowl-

edged if it checks error free. If no acknowledgment is received, the base station will re-

transmit the same data on the next hop. In point-to-point operation, by default the remote will send the data in its transmit buffer on each hop, up to the limit set by its RemoteSlotSize parameter. If desired, the MinPack-

etLength and TxTimeout parameters can be set to non-zero values, which configures the remote to wait until the specified amount of data is available or the specified delay had expired before transmitting. If the remote is buffering more data than can be sent on one hop, it will send the remaining data in subsequent hops. The remote adds its own address, a packet sequence number and error checking bytes to the data when it is transmitted. These additional bytes are not output at the base station if the base station is in transpar-

ent mode. When a transmission is received by the base station, it will be acknowledged if 2008 by RF Monolithics, Inc. 6 M-0500-0000 Rev D DNT500 it checks error free. If no acknowledgment is received, the remote will retransmit the same data on the next hop. 2.5.2 Point-to-Multipoint Network Operation In a point-to-multipoint network, the base station is usually configured for protocol for-

matting, unless the applications running on each remote can determine the datas destina-

tion from the data itself. Protocol formatting adds the address of the destination (remote) and other overhead bytes to the user data. If the addressed remote is using transparent for-

matting, the destination address and the other overhead bytes are removed. If the remote is using protocol formatting, the destination address and the other overhead bytes are out-

put with the user data. A remote can operate in a point-to-multipoint network using either transparent or proto-

col formatting, as the base station is always the destination. In transparent operation, a remote will add addressing, a packet sequence number and error checking bytes as in a point-to-point network. When the base station receives the transmission, it will format the data to its host according to its formatting configuration. A remote running in transparent mode in a point-to-multipoint network will often have the MinPacketLength and TxTime-

out parameters set to non-zero values to reduce the chance of transmission collisions. This is covered in more detail in section 2.6.3. 2.6 Full-Duplex Serial Data Communications From an host applications perspective, DNT500 serial communications appear full du-

plex. Both the base station host application and each remote host application can send and receive serial data at the same time. At the radio level, the base station and remotes do not actually transmit at the same time. If they did, the transmissions would collide. As discussed earlier, the base station transmits a synchronization signal at the beginning of each hop followed by its user data. After the base station transmission, the remotes can transmit. Each base station and remote transmission may contain all or part of a complete message from its host application. From an applications perspective, the radios are communicating in full duplex since the base station can receive data from a remote before it completes the transmission of a message to the remote and visa versa. 2.7 Channel Access The DNT500 provides two methods of channel access: CSMA or TDMA. Each method supports several options as shown in the table below. The channel access setting is dis-

tributed to all remotes in the base station status packet, so changing it at the base station sets the entire network. Carrier Sense Multiple Access (CSMA) is very effective at han-

dling packets with varying amounts of data and/or packets sent at random times from a large number of remotes. The DNT500 includes a CSMA polling mode for coordinated remotes and a CSMA contention mode for uncoordinated and/or reporting remotes. Time Division Multiple Access (TDMA) provides a scheduled time slot for each remote to transmit on each hop. The default DNT500 access mode is CSMA polling. 2008 by RF Monolithics, Inc. 7 M-0500-0000 Rev D Max # of Remotes Remote Slot Size DNT500 Access Mode Description 0 1 2 (default) TDMA dynamic slots 3 4 CSMA polling CSMA contention TDMA fixed slots TDMA with PTT 1024 1024 up to 15 up to 15 1024 manual manual automatic automatic automatic 2.7.1 CSMA Modes When using CSMA, each remote with data to send listens to see if the channel is clear and then transmits. If the channel is not clear, a remote will wait a random period of time and listen again. CSMA works best when a large or variable number of remotes transmit infrequent bursts of data. There is no absolute to the number of remote radios that can be supported in this mode. For a DNT500 network, a maximum of 255 remotes can be sup-

ported if base station join-leave tracking is required, or a maximum of 1024 remotes is suggested if base station join-leave tracking is not required. The illustration below com-

pares TDMA to CSMA operation. There are two important parameters related to CSMA operation. The CSMA_MaxBackoff parameter defines the maximum time that a remote will wait after a collision before at-

tempting to send the packet again (back-off interval). The CSMA_Persistence parameter sets the probability that a remote will transmit immediately rather than first waiting for a pre-transmit delay interval. Persistence is a one-byte parameter with a range of 0x00 to 0xFF:

0xFF = 100% probability 0x00 = 0% probability CSMA polling (Mode 0) is used for point-to-point systems and point-to-multipoint sys-

tems where only one remote at a time can receive data to transmit (ModBus, etc.). Since only one remote will attempt to transmits at a time, the CSMA_Persistence parameter is fixed at 0xFF for minimum latency. This mode provides maximum throughput since there is no contention between remotes and the entire portion of the hop frame following the base station transmission is available for a remote to transmit. The user can set 2008 by RF Monolithics, Inc. 8 M-0500-0000 Rev D DNT500 CSMA_MaxBackoff, BaseSlotSize and RemoteSlotSize parameters when using this mode. Note that a CSMA_Persistence parameter setting of 0xFF would lead to collisions if more than one remote tried to transmit. Applications where more than one remote can receive serial data to transmit at the same time, or where periodic reporting and/or event report-

ing are enabled should not use this mode. CSMA Contention (Mode 1) provides classical CSMA channel access, and gives the user control over both the CSMA_MaxBackoff and CSMA_Persistence parameters. This mode is well-suited for large numbers of uncoordinated remotes, and/or where periodic/event reporting is used. In addition to CSMA_MaxBackoff and CSMA_Persistence, the user can set the BaseSlotSize and RemoteSlotSize parameters when using this mode. The following guidelines are suggested for setting CSMA_Persistence:

For lightly loaded CSMA contention networks, increase CSMA_Persistence to 0x80 or higher to reduce latency. For heavily loaded CSMA contention networks, reduce CSMA_Persistence to 0x20 or lower for better throughput. CSMA modes can optionally track remotes entering and leaving the network for up to 255 remotes. The base station is operated in protocol mode and is configured to generate a CONNECT message for its host when a remote registers, and a DISCONNECT mes-

sage when the remotes registration lease expires. The base station in a CSMA network can generate CONNECT messages for more than 255 remotes. This allows the host application to track remotes entering and leaving a large CSMA network by creating a table of MAC addresses and periodically sending a ping to each remote in the table. Failure to answer the ping indicates the remote is no longer active in the network. The CSMA modes work well in many applications, but CSMA does have some limita-

tions, as summarized below:

Bandwidth is not guaranteed to any remote. Marginal RF links to some remotes can create a relatively high chance of collisions in heavily loaded networks. 2.7.2 TDMA Modes The TDMA modes provide guaranteed bandwidth to some or all of the remotes in the network. Remotes that register with the base station receive several special parameters, including ranging information and a specific channel access slot assignment. TDMA reg-

istrations are always leased and must be renewed every 250 hops. The DNT500 provides three different modes of TDMA access, as discussed below. TDMA Dynamic Slots (Mode 2) is used for general-purpose TDMA applications where scaling the capacity per slot to the number of active remotes is automatic. Each remote that registers with the base receives an equal time slice. As new remotes join, the size of the TDMA slots shrink accordingly. The number of slots, individual slot start times, and 2008 by RF Monolithics, Inc. 9 M-0500-0000 Rev D DNT500 the RemoteSlotSize are computed automatically by the DNT500 network in this mode. The user should note that the bandwidth to each remote will change immediately as re-

motes join and leave the network. TDMA Fixed Slots (Mode 3) is used for applications that have fixed data throughput re-

quirements, such as isochronous voice or streaming telemetry. The slot start time and the RemoteSlotSize are computed automatically by the DNT500 network in this mode. The user must set the number of slots. TDMA with PTT (Mode 4) supports remotes with a "push-to-talk" feature, also referred to as "listen-mostly" remotes. This mode uses fixed slot allocations. Remotes can be reg-

istered for all but the last slot. The last slot reserved for the group of remotes that are usu-

ally listening, but occasionally need to transmit. In essence, the last slot is a shared chan-

nel for this group of remotes. When one of them has data to send it keys its transmitter much like a walkie-talkie, hence the name push-to-talk (PTT). The slot start time and the RemoteSlotSize are computed automatically by the DNT500 network in this mode. The user must specify the number of slots. The last slot is reserved for the PTT remotes. The user must configure PTT remotes individually to select Mode 4 operation. The network makes no guarantee that PTT remote transmissions will not col-

lide in the shared slot. The user's application must ensure that no more than one PTT re-

mote is using the slot at a time. 2.7.3 Network Configuration Planning Value Useable Range Parameter RF_DataRate HopDuration TDMA_MaxNumSlots BaseSlotSize RemoteSlotSize Some planning is necessary for a DNT500 network to coordinate the RF_DataRate, HopDuration, BaseSlotSize, RemoteSlotSize, MinPacketLength, TxTimeout and TDMA_MaxNumSlots parameters to achieve a practical configuration. This is true even for modes that automatically compute some of these parameters. Each parameter has a limited range of usable values, as shown in the table below:

MinPacketLength The highest RF data rate, 500 kb/s, provides the highest throughput and the most flexibil-

ity with respect to the other parameters. The maximum RF power that can be used at 500 kb/s is 19 dBm. The three lower data rates can run up to 28 dBm of RF power, and the receiver becomes progressively more sensitive as the data rate is lowered. So for greatest operating range, one of the three lower RF data rates should be used. The maximum DNT500 HopDuration setting is about 200 ms regardless of the RF data rate chosen. For a given data rate, FHSS operation tends to become more robust as hop duration is reduced. However, running with a shorter hop duration may require setting the 500, 200, 115.2 and 38.4 kb/s 2..204.75 ms (0.05 ms/count) max number of TDMA slots (MNS) for remotes max number of user data bytes transmitted per hop max number of user data bytes transmitted per hop 0..255 bytes 0..255 ms (1 ms/count) 0..3 40..4095 1..15 6..232 3..243 0..255 0..255 TxTimeOut 2008 by RF Monolithics, Inc. 10 M-0500-0000 Rev D DNT500 BaseSlotSize and RemoteSlotSize parameters well below their maximum values at the lower RF data rates. The equation below calculates the minimum hop duration needed at a given RF data rate for a specific number of remote slots and BaseSlotSize and Re-

moteSlotSize parameter settings. Support for optimizing a DNT500 configuration for a specific application is also available from RFMs Technical Support Group. See Section 10.3. for technical support contact information. The minimum required hop duration for a DNT500 configuration is:

THD = TBRO + NRS*TRO + TRFB*(BBSS + NRS*BRSS) Where:

THD TBRO NRS TRO TRFB BBSS BRSS is the minimum required hop duration in milliseconds is the base and registration request overhead time for each hop (RF data rate dependent) is the number of remote slots is the remote overhead time for each hop (RF data rate dependent) is the transmission time for one user byte (RF data rate dependent) is the BaseSlotSize parameter in bytes is the RemoteSlotSize parameter in bytes The constants in the equation for each RF data rate are given in the following table:

RF Data Rate kb/s 38.40 115.2 200 500 TBRO ms 11.620 4.953 3.540 2.388 TRO ms 4.817 2.039 1.450 0.970 TRFB ms 0.2080 0.0694 0.0400 0.0160 For Example 1, consider a point-to-point CSMA Mode 0 system operating at 38.4 kb/s with the BaseSlotSize parameter set to 133 bytes and the RemoteSlotSize parameter set to 128 bytes. The minimum hop duration needed to support one-hop transmissions of full slot size messages in both directions for this configuration is:

= 11.620 + 1*4.817 + 0.2080*(133 + 1*128)

= 16.437 + 0.2080*261

= 70.725 ms The closest programmable hop duration is 70.750 ms. It should be noted that the base station operating system will commandeer 5 bytes from the BaseSlotSize allocation in Mode 0 and up to 13 bytes in Mode 1 to send reception ac-

knowledgements (ACKs) back to the remotes. The BaseSlotSize should be sized accord-

ingly. In the above example, the BaseSlotSize parameter is set five bytes larger than the RemoteSlotSize parameter to accommodate the ACK bytes. When running a point-to-multipoint network with uncoordinated remotes using CSMA Mode 1, it is useful to set NRS to a value of 3 or higher in the equation. Although CSMA 2008 by RF Monolithics, Inc. 11 M-0500-0000 Rev D DNT500 does not create reserved time slots for remotes, extending the hop duration this way al-

lows several uncoordinated transmissions of user data and/or periodic/event reports to ar-

rive in the same slot with a relatively few collisions. The performance of a CSMA Mode 1 system can often be helped by setting the Min-

PacketLength and TxTimeout parameters on any remotes running transparent mode to non-zero values, especially if host messages only contain a few bytes each and transmis-

sion latency is not critical. For starting point values, set the MinPacketLength equal to the RemoteSlotSize and TxTimeout to at least three times the hop duration. This will help avoid excessive transmission collisions due to having many packets transmitted, each car-

rying only a small amount of user data on top of the relatively large packet overhead structure. For Example 2, consider a TDMA Mode 2 or 3 system operating at 500 kb/s. Up to 10 registered remotes need to be accommodated. A BaseSlotSize of 138 bytes is needed, and each remote needs enough slot time to support a RemoteSlotSize of 64 bytes. The mini-

mum hop duration needed to support this configuration is:

= 2.388 + 10*0.970 + 0.0160*(138 + 10*64)

= 12.088 + 0.0160*778

= 24.536 ms The closest programmable hop duration is 24.550 ms. In all TDMA modes, the base station operating system will commandeer one byte from the BaseSlotSize allocation for each registered remote to send ACKs to the remotes. The BaseSlotSize and MinPacketLength should be sized accordingly. 2.7.4 Serial Port Operation DNT500 networks are often used for wireless communication of serial data. The DNT500 supports serial baud rates from 1.2 to 460.8 kb/s. Listed in the table below are the supported data rates and their related byte data rates and byte transmission times for an 8N1 serial port configuration:

Baud Rate Byte Data Rate Byte Transmission Time kb/s 1.2 2.4 4.8 9.6 19.2 38.4 115.2 230.4 460.8 kB/s 0.12 0.24 0.48 0.96 1.92 3.84 11.52 23.04 46.08 ms 8.3333 4.1667 2.0833 1.0417 0.5208 0.2604 0.0868 0.0434 0.0217 To support continuous full-duplex serial port data flow, an RF data rate much higher than the serial port baud rate is required for FHSS. Radios transmissions are half duplex, and 2008 by RF Monolithics, Inc. 12 M-0500-0000 Rev D DNT500 there are overheads related to hopping frequencies, assembling packets from the serial port data stream, transmitting them, sending ACKs to confirm error-free reception, and occasional transmission retries when errors occur. For Example 3, consider a CSMA Mode 0 transparent data system operating at 500 kb/s with the BaseSlotSize parameter set to 133 bytes (128 bytes net after the five byte alloca-

tion for sending ACKs) and the RemoteSlotSize parameters set to 128 bytes. The mini-

mum hop duration needed to efficiently support this configuration is:

= 2.388 + 1*0.970 + 0.0160*(133 +1*128)

= 3.358 + 0.0160*261

= 7.534 ms Setting the hop duration to 7.55 ms, the average full-duplex serial port byte rate that can be supported under error free conditions is:

128 Bytes /7.55 ms = 16.942 kB/s, or 169.42 kb/s for 8N1 Continuous full-duplex serial port data streams at a baud rate of 115.2 k/bs can be sup-

ported by this configuration, provided only occasional RF transmission errors occur. Plan on an average serial port data flow of 75% of the calculated error-free capacity for gen-

eral-purpose applications, and 50% of the calculated error-free capacity for RF challeng-

ing applications such as vehicle telemetry and heavy industrial process environments. Most applications do not require continuous serial port data flow. The DNT500 transmit and receive buffers hold at least 1024 bytes and will accept brief bursts of data at high baud rates, provided the average serial port data flow such as shown in Example 3 is not exceeded. It is strongly recommended that the DNT500 host use hardware flow control. The host must send no more than 32 bytes additional bytes to the DNT500 when the DNT500 de-asserts the hosts CTS line. In turn, the DNT500 will send no more than one byte following the host de-asserting its RTS line. Three-wire serial port operation is al-

lowed by connecting the DNT500 CTS output to its RTS input. However, three-wire op-

eration should be limited to applications that send small bursts of data occasionally at an average serial port data flow less than 50% of the calculated error-free capacity. Data loss is possible under adverse RF channel conditions when using three-wire serial operation. 2.7.5 Sleep Mode To save power in applications where a remote transmits infrequently, the DNT500 sup-

ports a Sleep Mode. Sleep Mode is entered by switching DTR Pin 11 on the DNT500 from logic low to high. While in Sleep Mode, the DNT500 consumes less than 0.5 mA. This mode allows a DNT500 to be powered off while its host device remains powered. After leaving Sleep Mode (Pin 11 low to high), the radio must re-synchronize with the base station and re-register. 2008 by RF Monolithics, Inc. 13 M-0500-0000 Rev D 3. DNT500 HARDWARE DNT500 The major components of the DNT500 include a 900 MHz FHSS transceiver and a 32-bit microcontroller. The DNT500 operates in the frequency band of 902 to 928 MHz. There are 32 selectable hopping patterns including patterns compatible the frequency alloca-

tions in the US, Canadian, Australian and New Zealand. The DNT500 has six selectable RF output power levels: 0, 10, 19, 24, 27 and 28 dBm. Also, there are four selectable RF transmission rates: 38.4, 115.2, 200 and 500 kb/s. The power level is firmware inter-

locked to a maximum of 19 dBm at 500 kb/s to assure regulatory compliance. The DNT500 includes a low-noise preamplifier protected by two SAW filters, providing an excellent blend of receiver sensitivity and out-of-band interference rejection. The DNT500 provides a variety of hardware interfaces. There are two UART serial ports, one for data and a second for diagnostics. The data port supports baud rates from 1.2 to 460.8 kb/s and the diagnostic port supports baud rates from 38.4 to 460.8 kb/s. Other hardware interfaces include an SPI interface, three 10-bit ADC inputs, two 8-bit resolu-

tion PWM (DAC) outputs, and six general purpose digital I/O ports. Four of the digital I/O ports support an optional interrupt-from-sleep mode when configured as inputs. A 3.6 Vdc signal can be switched on the RF output port for diversity antenna control. The radio is available in two mounting configurations. The DNT500 is designed for solder re-

flow mounting. The DNT500P is designed for plug-in connector mounting. 2008 by RF Monolithics, Inc. 14 M-0500-0000 Rev D

6

, E

C H

E

H

J H

A H

4 A C

. E

J A H

. E

J A H 8

2 9

) 2 9

2 1

2 1

2 1

2 1

4

E

1

6

5

4

. 1

, 7

) 4 6

4

, 7

) 4 6

6

4

5

6 5 2 1

5 5 5 2 1

5 1 5 2 1

1 5

6

4 6

4 2 9 4 2 4

. E

J A H

5 1 5

2

6

6 4 A C

8

8 4 5 8

, 4 5 8

4

. 4 5 5 1

, 6 4

5

7

) 4 6

4

, 7

) 4 6

6

7

) 4 6

4 6 5 7

) 4 6

6 5

2 1

2 1

4 5 8

6

, 4 5 8

, 4 5 8

, 4 5 8

, 8

, 5 2 1

5

6

, DNT500 3.1 Specifications The DNT500 specifications are listed in the table below:

Characteristic Sym Notes Minimum Typical Maximum Units Operating Frequency Range FCC 15.247 FHSS FCC 15.247 Digital Modulation (DSS) Number of Hopping Patterns Hop Dwell Time Number of RF Channels RF Data Transmission Rates Receiver Sensitivity 10-5 BER @ 38.4 kb/s 10-5 BER @ 500 kb/s Transmitter RF Output Power Levels Optimum Antenna Impedance RF Connection Network Topologies Access Schemes Number of Network Nodes TDMA CSMA ADC Input Range ADC Input Resolution Signal Source Impedance for ADC Reading PWM (DAC) Output Range PWM (DAC) Output Resolution Primary Serial Port Baud Rates Diagnostic Serial Port Baud Rates Digital I/O:

Logic Low Input Level Logic High Input Level Logic Input Internal Pull-up Resistor Logic Input Internal Pull-down Resistor Power Supply Voltage Range Power Supply Voltage Ripple Receive Mode Current Transmit Mode Current DTR High Sleep Current Operating Temperature Range 1 1 1 1 VCC 902.75 927.25 MHz 38.4, 115.2 and 200 kb/s, up to 28 dBm 500 kb/s, up to 19 dBm 5 32 38.4, 115.2, 200 and 500

-108

-94 0, 10, 19, 24, 27, 28 50 200 50 U.FL Connector or PCB Pad Point-to-Point, Point-to-Multipoint, Mesh TDMA and CSMA 0 0 10 15 1024 3.3 10 3.3 8 1.2, 2.4, 4.8, 9.6, 19.2, 38.4, 115.2, 230.4, 460.8 38.4, 115.2, 230.4, 460.8

-0.5 2 50 50

+3.3

-40 50 0.8 3.3 200 180

+5.5 10 900 0.5 85 ms kb/s dBm dBm dBm V bits K V bits kb/s kb/s V V K K Vdc mVP-P mA mA mA oC Operating Relative Humidity Range 1. RF output power is interlocked in firmware to a maximum of 19 dBm at the 500 kb/s RF data rate to assure compliance with regulatory requirements. 10 90

2008 by RF Monolithics, Inc. 15 M-0500-0000 Rev D 3.2 Module Interface DNT500 Electrical connections to the DNT500 are made through the I/O pads and through the I/O pins on the DNT500P. The hardware I/O functions are detailed in the table below:

Pad Description Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 RSVD RSVD ADC_REF RSSI GPIO0 GPIO1 GPIO2 GPIO3 PWM0 PWM1 SLEEP ADC0 ADC1 ADC2 Reserved pad. Leave unconnected. Reserved pad. Leave unconnected. ADC supply and external full scale reference voltage input. Voltage range is 2.4 to 3.3 Vdc. Connect pad 34 to this input to reference the ADC full scale reading to the modules 3.3 V regulated supply. Analog voltage proportional to received signal strength, range 0 to 3.3 V. Configurable digital I/O port 0. When configured as an input, an internal pull-up resistor can be selected and interrupt from sleep can be invoked. When configured as an output, the power-on state is also configurable. Configurable digital I/O port 1. Same configuration options as GPIO0. Configurable digital I/O port 2. Same configuration options as GPIO0. Configurable digital I/O port 3. Same configuration options as GPIO0. Pulse-width modulated output 0 with internal low-pass filter. Provides an 8-bit DAC resolution. Pulse-width modulated output 1 with internal low-pass filter. Provides an 8-bit DAC resolution. Default functionality is active high module sleep input. When switched low after sleep, the module executes a power-on reset. 10-bit ADC input 0. Full scale reading is referenced to the ADC_REF input. 10-bit ADC input 1. Full scale reading is referenced to the ADC_REF input. 10-bit ADC input 2. Full scale reading is referenced to the ADC_REF input. EX_SYNC Optional rising-edge triggered input for synchronizing co-located base stations. See External-

SyncEn on Page 25 for additional details. DIAG_TX Diagnostic output (for factory use). DIAG_RX Diagnostic input (for factory use).

/CFG VCC GND GND GPIO4 GPIO5 RSVD ACT

/DCD Protocol selection input. Leave unconnected when using software commands to select trans-

parent/protocol mode (default is transparent mode). Logic low selects protocol mode, logic high selects transparent mode. 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. Configurable digital I/O port 4. When configured as an input, an internal pull-up resistor can be selected. When configured as an output, the power-on state is configurable. Configurable digital I/O port 5. Same configuration options as GPIO4. Reserved pad. Leave unconnected. Data activity output, logic high when data is being transmitted or received. Default functionality is data carrier detect output, which provides a logic low on a remote when the module is locked to FHSS hopping pattern and logic low on a base station when at least one remote is connected to it. 2008 by RF Monolithics, Inc. 16 M-0500-0000 Rev D Pad Name Description DNT500 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 RSVD RSVD RSVD Reserved pad. Leave unconnected. Reserved pad. Leave unconnected. Reserved pad. Leave unconnected.

/UART0_RTS Default functionality is UART flow control input for the modules host. A logic low allows data flow from the module to the host; a logic high blocks data flow from the module to the host. UART0_RXD UART received data output to host from module. UART0_TXD UART host data input to be transmitted by module.

/UART0_CTS UART flow control output from the module to the host. A logic low should allow data flow from the host; a logic high should block data flow from the host. Modules +3.3 V regulated supply output. Connect to pad 3 to support 3.3 V full scale and/or ratiometric ADC readings, etc. Current drain on this output should be no greater than 5 mA. Active low SPI enable (slave). This input must be held low for the duration of an SPI transmis-

sion. VMOD SPI_NSS SPI_MOSI SPI port data output. SPI_MISO SPI port data input. SPI_SCLK SPI port clock signal.

/RESET Active low module hardware reset. BOOT_LOAD Logic high at power up enables module boot loader. Hold low for normal operation. GND RFIO GND RF ground (DNT500 only). Connect to the host circuit board ground plane. Alternate RF port to the U.FL connector (DNT500 only). The antenna can be connected to this port with a 50 stripline or coaxial cable. Leave unconnected when using the U.FL connector. RF ground (DNT500 only). Connect to the host circuit board ground plane. 3.3 Input Voltages DNT500 radio modules can operated from an unregulated DC input (Pad/Pin 19) in the range of 3.3 (trough) to 5.5 V (peak) with a maximum ripple of 5% over the temperature range of -40 to 85 C. Applying AC, reverse DC, or a DC voltage outside the range given above can cause damage and/or create a fire and safety hazard. Further, care must be taken so logic inputs applied to the radio stay within the voltage range of 0 to 3.3 V. Sig-

nals applied to the analog inputs must be in the range of 0 to ADC_REF(Pad/Pin 3). Ap-

plying a voltage to a logic or analog input outside of its operating range can damage the DNT500 module. 3.4 ESD and Transient Protection The DNT500 and DNT500P circuit boards are electrostatic discharge (ESD) sensitive. ESD precautions must be observed when handling and installing these components. In-

stallations must be protected from electrical transients on the power supply and I/O lines. This is especially important in outdoor installations, and/or where connections are made to sensors with long leads. Inadequate transient protection can result in damage and/or create a fire and safety hazard. 2008 by RF Monolithics, Inc. 17 M-0500-0000 Rev D DNT500 3.5 Interfacing to 5 V Logic Systems All logic signals including the serial ports on the DNT500 are 3.3 V signals. To interface to 5 V signals, the resistor divider network shown below must be placed between the 5 V signal outputs and the DNT500 signal inputs. The output voltage swing of the DNT500 3.3 V signals is sufficient to drive 5 V logic inputs. 3.6 Power-On Reset Requirements The DNT500 has an internal reset circuit that generates and maintains the DNT500 in a reset state until the power supply voltage reaches 3.3 volts for 100 milliseconds. This re-

set circuit protects the radio and non-volatile memory from brown-out voltage conditions. If devices that communicate with the DNT500 have shorter reset periods, an allowance must be made to allow the DNT500 to come out of reset. Commands and data sent before the DNT500 is out of reset will be ignored. 3.7 Analog RSSI Output Pin 4 on the DNT500 provides a 0.3 to 3.0 V output proportional to received signal strength in dB, as follows:

VRSSI = 0.03*SRF + 3.6 Where:

The analog RSSI output on a DNT500 remote represents the signal strength of the last base station transmission received. The RSSI output on a base station represents the sig-

nal strength of the last remote transmission heard. is the RSSI output in volts, over the range of 0.3 to 3.0 V is the RF signal strength in dBm, over the range of -110 to -20 dBm VRSSI SRF 3.8 Mounting and Enclosures DNT500 radio modules are mounted by reflow soldering them to a host circuit board. DNT500P modules are mounted by plugging their pins into a set of mating connectors on the host circuit board. Refer to the DNT500 data sheet for a suitable solder reflow profile and details of the connectors for the DNT500P. DNT500 radio module enclosures must be made of plastics or other materials with low RF attenuation to avoid compromising antenna performance. Metal enclosures are not suitable as they will block antenna radiation and reception. Outdoor enclosures must be water tight, such as a NEMA 4X enclosure. 2008 by RF Monolithics, Inc. 18 M-0500-0000 Rev D

8

C E

6

DNT500 3.9 Connecting Antennas A U.FL miniature coaxial connector is the primary RF connection point on the DNT500, and the only RF connection point on the DNT500P. On the DNT500, it is also possible to connect an antenna using a stripline from pad 42 instead of the U.FL connector. It is im-

portant that this connection be implemented as a 50 ohm stripline trace. A short coaxial jumper cable should be used to connect to between the U.FL connector on the DNT500P and the host circuit board U.FL connector. The host PCB U.FL connector should connect to the antenna or antenna connector with a 50 ohm stripline trace. The design details of the stripline are covered in the DNT500 Data Sheet. 3.10 Labeling and Notices DNT500 FCC Certification - The DNT500 hardware has been certified for operation un-

der FCC Part 15 Rules, Section 15.247. The antenna(s) used for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co-located or operating in conjunction with any other antenna or transmitter. DNT500 FCC Notices and Labels - This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause harm-

ful interference, and (2) this device must accept any interference received, including in-

terference that may cause undesired operation. A clearly visible label is required on the outside of the users (OEM) enclosure stating that this product contains a DNT500 transceiver assembly, FCC ID: HSW-DNT500P. WARNING: This device operates under Part 15 of the FCC rules. Any modification to this device, not expressly authorized by RFM, Inc., may void the users authority to oper-

ate this device. Canadian Department of Communications Industry Notice - IC: 4492A-DNT500P This apparatus complies with Health Canadas Safety Code 6 / IC RSS 210. ICES-003 This digital apparatus does not exceed the Class B limits for radio noise emissions from digital apparatus as set out in the radio interference regulations of Industry Canada. Le present appareil numerique nemet pas de bruits radioelectriques depassant les limites applicables aux appareils numeriques de Classe B prescrites dans le reglement sur le brouillage radioelectrique edicte par Industrie Canada. 2008 by RF Monolithics, Inc. 19 M-0500-0000 Rev D DNT500 4. PROTOCOL MESSAGES 4.1 Protocol Message Formats The DNT500 is configured and controlled through a series of protocol mode messages. All protocol mode messages have a common header format:

0 1 2 3 N SOP Length PktType variable number of arguments LRC*

The scale above is in bytes. General comments:

The Start-of-Packet (SOP) character, 0xFB, is used to distinguish the beginning of a message and to assure synchronization in the event of a glitch on the serial port at startup. The Length byte is defined as the length of the remainder of the message following the length byte itself (or the length of the entire message - 2). If the LRC is enabled, it is included in the length. The Packet Type (PktType) byte specifies the type of message. It is a bitfield-oriented Bits 7-6 Reserved for future use Event - set to indicate this message is an event Bit 5 Bit 4 Reply - set to indicates this message is a reply Bits 3-0 Type - indicates the message type/command specifier, decoded as follows:

As indicated, the lower 4 bits (3-0) specify a message type. Bit 4 is a modifier indicat-

ing that the message is a command or a reply. A reply message has the original com-

mand type in bits 3:0, with bit 4 set to one. Arguments vary in size and number depending on the type of message and whether it is a message sent from the host or is a reply from the radio; see the table provided be-

low for reference. The LRC is an optional checksum byte that verifies the integrity of the message re-

ceived. It is the two's complement of the sum of all the bytes in the message. If the sum is larger than 1 byte, only the LSB is used. For example, 0xFB 0x05 0x04 0x01 0x0A 0x00 0x01 LRC = 0xF0. Messages that are generated on the serial interface by the user are referred to as host messages. Messages that are generated by the radio are referred to as reply messages. For many message types, there is a reply message that corresponds to a host message. For example, when the host sends a TxData message, the radio will reply to indicate the status of the transmission, whether it succeeded or failed. Some message types are host-only or reply-only; please refer to the table for specifics. 4.1.1 Serial message types Each message generally has two forms, a command from the host and a reply from the radio. Depending on the direction, they have different arguments as shown in the table 2008 by RF Monolithics, Inc. 20 M-0500-0000 Rev D DNT500 below. Event messages from the radio such as receive data packets or status announce-

ments make up a third category of messages. To assist in interpreting the command-reply data flow, the direction is indicated by Bit 4 in the message type. For example, an Enter-

ProtocolMode command from the host is message type 0x00, and the EnterProtocol-

ModeReply from the radio is message type 0x10. Event messages, including RxData, RxEvent and ANNOUNCE, packets are indicated by setting Bit 5 high in the type byte. If multiple arguments are to be provided, they are to be concatenated in the order shown. Little-Endian byte format is used for all multi-byte arguments, where the lowest order byte is the left byte of the argument and the highest order byte in the right byte of the ar-

gument. Message Type Code Reply Event Description Direction Arguments Com-

mand 0x00

0x10 0x01

0x11 0x02

0x12 0x03

0x13 0x04

0x14 0x05

0x0A 0x15

0x1A 0x0B

0x1B

EnterProtocolMode EnterProtocolModeReply ExitProtocolMode ExitProtocolModeReply SoftwareReset SoftwareResetReply GetRegister GetRegisterReply SetRegister SetRegisterReply TxData TxDataReply 0x26 RxData 0x27 Announce 0x28 RxEvent

GetRemoteRegister GetRemoteRegisterReply SetRemoteRegister SetRemoteRegisterReply Instrumentation

"DNT500"

none none none BootSelect none Reg, Bank, Span from Host from Radio from Host from Radio from Host from Radio from Host from Radio Reg, Bank, Span,Val Reg, Bank, Span, Val from Host none from Radio Addr, Data from Host from Radio TxStatus, Addr, RSSI from Radio Addr, RSSI, Data from Radio AnnStatus, add'l fields Addr, RSSI, Reg, Bank, Span,Val Addr, Reg, Bank, Span TxStatus, Addr, RSSI, Reg, Bank, Span, Val*

Addr, Reg, Bank, Span, Val from Host from Radio TxStatus, Addr, RSSI from Radio DiagInfo from Radio from Radio from Host

0x2F

*If TxStatus is non-zero in a GetRemoteRegisterReply, the Reg, Bank, Span and Val bytes will not be present in the message

= Register location (1 byte). Arguments:

Reg Bank = Register bank, which provides logical isolation from other data regions (1 byte). Span = Number of bytes of register data to get or set; must align to a parameter boundary (1 byte). Val

= Value to read/write to/from register (see table for size and acceptable range). 2008 by RF Monolithics, Inc. 21 M-0500-0000 Rev D DNT500 0 = Acknowledgement received. 1 = No acknowledgement received. 2 = (Remote) Not linked. 3 = Recipient holding for flow control. Data = User data (variable size, 0 to 128 bytes). Addr = MAC address of the sender for a reply or event, or recipient for a command (3 bytes). TxStatus = Result of last TxData operation (1 byte). RSSI = RSSI, range 0x01 to 0xFE. Values 0x00 & 0xFF have special meanings (1 byte). NwkID = Network identifier of network joined (1 byte). BaseMacAddr = MAC address of base that the remote joined (3 bytes). BootSelect = Code indicating whether to do a normal reset or a reset to the bootloader (1 byte). 0x00 = No RSSI measured because no ACK was received. 0xFF = No RSSI measured because packet was relayed.

(0 = normal reset, 1 = reset to bootloader) AnnStatus = Status announcement (1 byte). Additional fields are also reported depending on the status code:

Status code Add'l fields A0 = Radio has completed startup initialization. A1 = Base: Network formed, ready for data. A2 = Base: A remote has joined me. MacAddr (0xFF if none) A3 = Remote: Joined a network, ready for data. A4 = Remote: Exited network (base is out of range). NwkID A5 = Remote: Base has restarted. A7 = Base: Remote has left the network. none NwkID none Addr NwkID, BaseMacAddr, Range Status codes for error conditions JoinAddr = MAC address of radio joining (3 bytes). Range = Range measurement of radio joining. (1 byte). E0 = Protocol error -- invalid message type. E1 = Protocol error -- invalid argument. E2 = Protocol error -- general error. E3 = Protocol error -- parser timeout. E4 = Protocol error -- register is read-only. E8 = UART receive buffer overflow. E9 = UART receive overrun. EA = UART framing error. Add'l fields none none none none none none none none 4.1.2 Escape sequence The escape sequence is a sequence of bytes that the user can input in transparent mode to switch the radio to configuration mode. In the DNT500, we define the EnterProtocol-

Mode command as the ASCII escape sequence DNT500 (quotation marks are not part of the sequence). A radio that is already in protocol mode will respond to this command the same way as a radio that is in transparent mode. For the escape sequence to be recog-

nized, byte flow must pause at least 20 ms before the escape sequence is sent. 2008 by RF Monolithics, Inc. 22 M-0500-0000 Rev D DNT500 4.1.3 CFG select pin A falling edge on the CFG pin is the equivalent of entering the escape sequence to invoke the protocol mode. A rising edge on the CFG pin is the equivalent to sending the exit pro-

tocol command. 4.1.4 Flow control There are two flow control signals between the radio and the host, RTS and CTS. See Section 2.7.4 for flow control details. 4.1.5 Protocol mode data message example For Example 4, ASCII text Hello World is sent from the base station to a remote using a TxData command. The MAC address of the remote is 0x000102. The protocol format-

ting for the host message is:

0xFB 0x0F 0x05 0x02 0x01 0x00 0x48 0x65 0x6C 0x6C 0x6F 0x20 0x57 0x6F 0x72 0x6C 0x64 There are 15 bytes following the length byte, so the length byte is set to 0x0F. Note that the 0x000102 MAC address is entered in Little-Endian byte order 0x02 0x01 0x00. When an ACK to this message is received from the remote, the base station outputs a TxDataReply message to its host:

0xFB 0x06 0x15 0x00 0x02 0x01 0x00 0x80 The 0x00 TxStatus byte value indicates the ACK reception from the remote. The RSSI value is 0x80. If the remote is in protocol mode, the received message is output in the following format:

The message is output as an 0x26 event. Note that the RSSI value 0x8A is inserted be-

tween the remotes MAC address and the Hello World user data. 0xFB 0x10 0x26 0x02 0x01 0x00 0x8A 0x48 0x65 0x6C 0x6C 0x6F 0x20 0x57 0x6F 0x72 0x6C 0x64 4.2 Configuration Registers The configuration registers supported by the DNT500 are described below. Registers are sorted into banks according to similarity of function. 2008 by RF Monolithics, Inc. 23 M-0500-0000 Rev D 4.2.1 Bank 0 - Transceiver Setup DNT500 Bank Loc'n 00 00 00 01 00 02 04 00 05 00 15 00 00 16 18 00 19 00 1A 00 00 1B 1C 00 Name Size in R/W bytes Range Default, Options R/W1 DeviceMode R/W RF_DataRate R/W HopDuration R/W InitialNwkID R/W SecurityKey R/W SleepMode R/W SleepInterval R/W TxPower ExternalSyncEn R/W DiversityMode R/W JoinPermit R/W R/W UserTag 0 = Remote, 1= Base, 2 = PTT Remote 0 = 500, 1 = 200, 2 = 115.2, 3 = 38.4 kb/s, 0xFF = auto 0..2 0..4 4..4000 10 ms (0x00C8) 0..255 0xFF = broadcast 1 1 2 1 16 0..2128 0 = security disabled 1 2 1 1 1 1 16 0..1 0..216 0..5 0..1 0..1 0..1 0 = off, 1 = timer, 2 = interrupt 0 = off 1 = 10 dBm; 0 = 1, 2 = 19, 3 = 24, 4 = 27, 5 = 28 dBm 0 = disabled, 1 = input, 2 = output 0 = 0 V 0 = no join, 1 = remotes (default), 2 =any

"DNT500"

Note: These settings are individual to each module. DeviceMode Selects the operating mode for the radio: remote, base, or PTT remote (listen mostly re-

mote). Note that the setting takes effect immediately. RF_DataRate This sets the over-the-air RF data rate. Radios with different RF rates cannot intercom-

municate. The following codes are defined:

A setting of "auto" will cause a remote to scan all 4 possible RF rates for a network to join. A base set to "auto" will run at the maximum rate of 500 kb/s. A change to this set-

ting on the base will trigger an epoch change to reboot the network. 0x00 = 500 kb/s 0x01 = 200 kb/s 0x02 = 115.2 kb/s 0x03 = 38.4 kb/s 0xff = auto (default) HopDuration This sets the duration of the hop frame. The duration is set as a 12-bit value, 0.05 ms/count. InitialNwkID Selects the initial network ID that the radio will start (if a base) or join (if a remote). A value of 0xFF instructs a remote to operate in 'promiscuous mode' and join any network it finds (if set for a base, this will select the default network of 0x00.) The network ID also sets the base frequency at which the hopping pattern starts, as illustrated by the following equation:

2008 by RF Monolithics, Inc. 24 M-0500-0000 Rev D DNT500 FrequencyIndex[n] = HoppingPattern[n + 2*NetworkID mod 32]

This allows the user to coordinate frequency spacing of co-located networks to maintain a constant separation as they hop. SecurityKey This sets the 128-bit AES encryption key that will be used. The intent is for this to act like a password that all radios in the network are configured with. To protect the key, this is a write-only parameter for the user, unless the manufacturing write enable is set, in which case it is also readable. Refer to the section on Encryption for further information. SleepMode Sets the sleep mode. SleepInterval Sets the sleep interval as the number of superframes that a remote will sleep between wake intervals. A superframe interval is 64 hops. TxPower Sets the transmit power level:

0 = 0 dBm or 1 mW 1 = 10 dBm or 10 mW (default) 2 = 19 dBm or 79.4 mW 3 = 24 dBm or 250 mW 4 = 27 dBm or 500 mW 5 = 28 dBm or 1000 mW (1 W) When the data rate is set to 500 kb/s, the firmware interlocks the transmit power level to 19 dBm or less to comply with FCC regulations. ExternalSyncEn Enables the external sync input. This option allows a base radio's hopframes to be trig-

gered by an external synchronization signal. Valid settings are 0 = disabled, 1 = sync pin is input, 2 = sync pin is an output. This last mode allows a base radio to source the sync signal for another radio. DiversityMode The DNT500 supports the following diversity antenna switching options:

0 = 0 V on the diversity pin (default) 1 = 3.3 V on the diversity pin 2 = 0 - 3.3 V toggle on every hop frame 2008 by RF Monolithics, Inc. 25 M-0500-0000 Rev D DNT500 JoinPremit Valid parameter on a base only. Controls whether remote nodes are permitted to join the base. Parameter values are 0 = no joining permitted, 1 = remotes only may join, 2 = re-

motes or routers may join (future function). UserTag This is a user definable field intended for use as a location description or other identify-

ing tag such as a friendly name. 4.2.2 Bank 1 - System Settings Bank Loc'n Size in Name R/W bytes Range Default; Options 0x00 = North America;

0x01 = Australia, 0xFF = auto 2 = TDMA Dynamic Slots 00 01 02 03 04 05 06 07 08 09 0A 0..1 01 0..4 01 6..232 20 bytes 01 0..250 5 s (0 to disable) 01 0 = ARQ, 1 = redundant TX 0..1 01 5 attempts 0..16 01 0..15 8 slots 01 0..255 0xFF 01 0..255 5 ms 01 0..255 50 s (~4 miles) 01 0..1 01 Note: The base station propagates these setting to all remotes. R/W FrequencyBand AccessMode R/W BaseSlotSize R/W LeasePeriod R/W R/W ARQ_Mode ARQ_AttemptLimit R/W TDMA_MaxSlots R/W CSMA_Persistence R/W CSMA_MaxBackoff R/W R/W R/W MaxPropDelay 0 = use previous; 1 = increment 2 = random 1 1 1 1 1 1 1 1 1 1 1 EpochMode FrequencyBand This sets the range of frequencies over which the radio will operate. Two settings are de-

fined: North America (902-928 MHz) and Australia-New Zealand (915-928 MHz). AccessMode This sets the channel access mode that remotes will use to communicate with the base:

Access Mode Description 0 1 2 (default) TDMA dynamic slots 3 4 manual manual automatic automatic automatic 1024 1024 up to 15 up to 15 1024 Max # of Remotes Remote Slot Size CSMA polling CSMA contention TDMA fixed slots TDMA with PTT BaseSlotSize This sets the size of the base slot. This number is specified in terms of the number of ap-

plication payload bytes that can be supported. This value excludes the message length byte, the BASE_STATUS packet, the checksum and CRC bytes, and a presumed REG_REPLY packet. The BaseSlotSize indicates the number of bytes that are available for MAC and network ACKs, plus user data packets. This number does not include the 2008 by RF Monolithics, Inc. 26 M-0500-0000 Rev D DNT500 overhead required for headers of these packets, which must be factored into the slot size budget. To ensure that there is never a restriction on when registration or renewal may take place, space for a registration reply packet is always assumed. If this packet is not needed on a given hop, this space is unused. LeasePeriod This sets the duration for network address leases that remotes may receive from the base. If a period of zero is specified, then lease and network address functions are disabled. ARQ_Mode This sets the ARQ mode for delivery of application messages. In full ARQ mode, an ACK is expected from the receiving radio for each message addressed and sent to it. If no ACK is received, up to ARQ_AttemptLimit, efforts to send the data will be made, after which the message is discarded. In redundant transmit mode, each message is sent ex-

actly ARQ_AttemptLimit times. No ACKS are sent or expected. This is primarily useful in cases where the number of attempts is 2 or 3, the data flow is time-critical, and the overhead of sending ACKs is not desired. ARQ_AttemptLimit This sets the maximum number of attempts that will be made to send a data packet on the RF link. Setting this parameter to the maximum value of 15 is a flag value indicating that there should be no limit to the number of attempts to send each packet (infinite number of attempts). This mode is intended for point-to-point networks in serial data cable replace-

ment applications where absolutely no packets can be lost. TDMA_MaxNumSlots In TDMA access modes, this sets the number of slots that are allowed. In fixed slot mode, this allocates the number of slots directly. In dynamic slot mode, this sets the maximum number of slots that may be allocated according to the number of remotes that are registered. CSMA_Persistence In CSMA mode, this sets the 'persistence' parameter, or probability that a remote will transmit when it senses an open channel. Please refer to the section on Channel Access for more information. CSMA_MaxBackoff In CSMA mode, this sets the maximum length of time that a remote will back off for af-

ter a failed transmit attempt. Please refer to the section on Channel Access for more in-

formation. MaxPropDelay This is the maximum propagation delay that remotes and base will use in their slot timing calculations, in units of microseconds. This is used to pad the amount of time dedicated 2008 by RF Monolithics, Inc. 27 M-0500-0000 Rev D DNT500 to the signup slot. Increasing this value will subtract slightly from the overall slot time available to remotes for sending data. EpochMode This is a base-only parameter that governs how the base will select an epoch number at startup when it creates a network. In mode 0, the base will read the epoch number from NVRAM. In mode 1, it reads the value from NVRAM and increments it (and stores the result). In mode 2, it will generate a random epoch number at every startup. 4.2.3 Bank 2 - Status Registers (read only) Name Bank Loc'n 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 02 00 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F 10 11 12 14 15 MacAddress R/W R CurrNwkAddress R CurrNwkID R CurrRF_DataRate R CurrFreqBand R LinkStatus R RemoteSlotSize R TDMA_NumSlots R TDMA_SlotStart R TDMA_CurrSlot R HardwareVersion R FirmwareVersion R FirmwareBuildNum R Epoch R SuperframeCount R RSSI_Idle R RSSI_Last R R CurrAttemptLimit CurrRangeDelay R Size in bytes 3 1 1 1 1 1 1 1 1 1 1 1 2 1 1 1 1 1 1 as set fixed value Range Default 0..224 0..255 as set 0..255 as set 0..4 as set as set 0..1 0..1 current status 0..255 current size 0..15 0..255 current setting 0..15 0..255 0x00 = DNT500 rev A 0..255 current firmware load 0..216 current firmware load 0..255 as set 0..255 current value 0..255 as set 0..255 as set 0..255 as set 0..255 as set current slot MacAddress Returns the radio's unique 24-bit MAC address. CurrNwkAddress Returns the radio's current network address, if any. Some special values should be noted. The base always reports 0x00. If a remote does not have a network address, either be-

cause lease mode is not enabled or it has not yet received one, it reports 0xFF. This re-

turns the network ID of the network that the radio is currently assigned to or connected to. A value of 0xFF means the radio is in promiscuous mode and scanning for a network but has not yet joined one. CurrNwkID This returns the network ID of the network that the radio is currently assigned to or con-

nected to. A value of 0xFF means the radio is in promiscuous mode and scanning for a network but has not yet joined one. 2008 by RF Monolithics, Inc. 28 M-0500-0000 Rev D DNT500 CurrRF_DataRate This returns the RF data rate of the network that the radio is currently assigned to or con-

nected to. A value of 0xFF means the radio is scanning for a network but has not yet joined one. CurrFreqBand This returns the frequency band of the network that the radio is currently assigned to or connected to. A value of 0xFF means the radio is scanning for a network but has not yet joined one. LinkStatus This returns the radio's current connection status to the network. The following codes are defined:

0 = initializing 1 = unlinked, scanning for network 2 = linked RemoteSlotSize This returns the current remote slot size, defined as the maximum possible user data pay-

load size in bytes. In TDMA modes where the slot size is automatically computed, this value is read-only. In manual TDMA mode and CSMA mode, this value must be set by the user. This value excludes the message length byte, REMT_STATUS packet, and checksum and CRC bytes. It indicates the number of bytes available for REMT_DATA and/or REMT_DATA_EXTs. It does not include the overhead bytes required for these packets, which must be figured into the slot size budget. TDMA_NumSlots In TDMA access modes, this returns the number of slots currently allocated. TDMA_CurrSlot This returns the current TDMA slot number. in modes where the slot position is auto-

matically computed. In modes where this number is not applicable, the value is read as 0xFF. TDMA_SlotStart This returns the current TDMA slot position. In TDMA modes where the slot position is automatically computed, this value is read-only. HardwareVersion This returns an identifier indicating the type of radio. A value of 0x00 is defined for the DNT500 Rev A hardware. FirmwareVersion This returns the firmware version of the radio in 2-digit BCD format. 2008 by RF Monolithics, Inc. 29 M-0500-0000 Rev D DNT500 FirmwareBuildNum This returns the firmware build number, in binary format. Epoch Returns the current epoch number. SuperframeCount Returns the current superframe count. The superframe counter increments every 64 hops. RSSI_Idle Returns the last measurement of RSSI made during a time when the RF channel was idle. May be used to detect interferers. Read-only. RSSI_Last Returns the last measurement of RSSI made during receipt of an RF packet with valid CRC. Used for network commissioning and diagnostic purposes. CurrAttemptLimit This returns the value of ARQ_AttemptLimit currently in use (depending on the selected ARQ_Mode, it may not always match the local EEPROM value). CurrRangeDelay This returns the current propagation delay for this remote as measured from the base. 4.2.4 Bank 3 - Serial Bank Loc'n 03 03 03 00 01 03 R/W Name SerialRate R/W SerialParams R/W SerialControls R/W Size in bytes Range Default 0..216 0..7 0..7 2 1 1 115.2 kb/s (0x0004) 8N1 0X07 Serial rate in b/s = 460800/SerialRate SerialRate This sets the serial rate divisor according to the following formula:

Serial rate division setting for commonly used baud rates are:

Serial rate 460.8 kb/s 460.8 kb/s 230.4 kb/s 115.2 kb/s (default) 76.8 kb/s 57.6 kb/s 38.4 kb/s 28.8 kb/s Setting 0x0000 0x0001 0x0002 0x0004 0x0006 0x0008 0x000C 0x0010 2008 by RF Monolithics, Inc. 30 M-0500-0000 Rev D DNT500 0x0018 0x0030 0x0060 0x00C0 0x0180 19.2 kb/s 9.6 kb/s 4.8 kb/s 2.4 kb/s 1.2 kb/s Note that if a value of 0x0000 is specified, the maximum data rate of 460.8 kb/s will be selected. SerialParams This sets the serial mode options for parity and stop bits:

Mode Setting 0x00 0x01 0x02-03 0x04 0x05 0x06 0x07 No parity, 8 data bits, 1 stop bit No parity, 8 data bits, 2 stop bits Reserved Even parity, 8 data bits, 1 stop bit Even parity, 8 data bits, 2 stop bits Odd parity, 8 data bits, 1 stop bit Odd parity, 8 data bits, 2 stop bits Note that 8-bit data with no parity is capable of carrying 7-bit data with parity for com-

patibility without loss of generality for legacy applications that may require it. SerialControls This register affects the way the radio responds to the various serial control lines. Ena-

bling or disabling response to some serial control signals can facilitate communicating with devices that support only a reduced serial interface. The register is defined as a bit-

mask, with the following options:

bits 7..3 Reserved bit 2 bit 1 Base DCD mode. 1 = The base will only assert DCD when at least one remote is registered (default). 0 = The base always asserts DCD, regardless of whether any remotes are attached. RTS enable. 1 = Radio will respond to changes on the RTS control line (default). 0 = Radio ignores the RTS pin and assumes flow control is always asserted. SLEEP enable. 1 = Radio will respond to changes on the SLEEP (DTR) control line (default) 0 = Radio ignores the SLEEP (DTR) pin and is always in the awake state. bit 0 4.2.5 Bank 4 - Host Protocol Settings Bank Loc'n Name ProtocolMode 04 ProtocolOptions 04 04 TxTimeout MinPacketLength 04 04 00 01 02 03 04 StartupAnnEn R/W R/W R/W R/W R/W R/W Size in bytes 1 1 1 1 1 Range Default; Options 0..1 0 = transparent; 1 = protocol 0..255 5 ms 0..255 1 byte 0..1 0 = disabled; 1 = enabled 2008 by RF Monolithics, Inc. 31 M-0500-0000 Rev D DNT500 04 04 04 05 06 07 TransLinkAnnEn R/W EscapeSequenceEn R/W TransPtToPtMode R/W 1 1 1 0..1 0..2 0..1 0 = disabled; 1 = LINK announce 0 = enabled; 1 = startup, 2 = anytime 0 = multipoint, 1 = point-to-point ProtocolMode Selects the host protocol mode. The default is 0, which is transparent mode, meaning the radio conveys whatever characters that are sent to it transparently, without requiring the host to understand or conform to the DNT500's built-in protocol. This setting is recom-

mended for point-to-point applications for legacy applications such as wire replacements where another serial protocol may already exist. Setting this parameter to 1 enables the DNT500 host protocol, which is recommended for point-to-multipoint applications and is preferred for new designs. It is not necessary to define the same protocol mode for all ra-

dios in a network. For example, it is frequently useful to configure all the remotes for transparent mode and the base for protocol mode. Note that it is possible for the host to switch the radio from transparent mode to protocol mode and back if desired by transmit-

ting a special "escape sequence" code. See the section on the serial host protocol for more information. ProtocolOptions This is a bitmask that selects various options for the protocol mode. Default is 0x01. Enable output of Instrumentation packets. reserved Enable LRC checksum byte in serial protocol. Enable output of Announce packets. bit 7 bits 2..6 bit 1 bit 0 TxTimeout This sets the transmit timeout used for determining message boundaries in transparent data mode. Units are in milliseconds. The default is that a message boundary is deter-

mined whenever there is more than a 5 ms gap detected between consecutive characters. MinPacketLength This sets the minimum message length used for determining packet boundaries in trans-

parent data mode. The default is one byte. TransLinkAnnEn This enables a link announcement function for transparent mode. Whenever link is ac-

quired or dropped, the strings "<LINK>" or "<DROP>" are sent to the host. EscapeSequenceEn Enables or disables the escape sequence which can be used to switch from transparent mode to protocol mode. Enabled by default. Valid settings are 0 = disabled, 1 = one chance at startup, 2 = enabled at any time. TransPtToPtMode This controls the behavior for addressing packets in transparent mode. When this setting is zero (default), in transparent mode the base will direct packets to the broadcast address. This is useful for point-to-multipoint where the base is sending data to multiple remotes, 2008 by RF Monolithics, Inc. 32 M-0500-0000 Rev D DNT500 for instance in applications where a wireless link is replacing an RS-485 serial bus. When this setting is one, in transparent mode the base will direct packets to the last remote that registered with it. This is useful for point-to-point networks where there are only two endpoints, for instance in applications where a simple serial cable is being replaced. 4.2.6 Bank 5 - I/O Peripheral Registers Bank Loc'n 05 05 05 05 05 05 05 05 05 05 05 00 01 02 03 04 05 06 07 08 09 0A Name GPIO0 GPIO1 GPIO2 GPIO3 GPIO2 GPIO3 ADC0 ADC1 ADC2 PWM0 PWM1 R/W R/W R/W R/W R/W R/W R/W R R R R/W R/W in bits Default Size in Range bytes 1 1 1 1 1 1 2 2 2 2 2 1 1 1 1 1 1 10 10 10 9 9 0 0 0 0 0 0 N/A N/A N/A 0 0 GPIO0..5 Writing to these registers sets the corresponding driver for pins that are enabled outputs. Writing to pins that are enabled as inputs enables or disables the internal pull-up. Reading these registers returns the current level detected on the corresponding pin. ADC0..2 Read-only, returns the current 10-bit ADC reading for the selected register. See the dis-

cussion of the ADC_SampleIntvl parameter below. PWM0..1 Sets the PWM (DAC) outputs. The DC voltage derived from the integrated low-pass fil-

ters on the PWM output provides and effective DAC resolution of 8 bits. The range of this parameter is 0x0000 to 0x0100. 4.2.7 Bank 6 - I/O setup R/W bytes in bits Default; Options Size in Range Name Bank Loc'n 06 06 06 06 06 06 06 06 06 06 06 00 01 02 03 04 05 06 07 09 0B 0D GPIO_Dir R/W GPIO_Init R/W GPIO_Alt R/W GPIO_MessageMode R/W GPIO_SleepMode R/W GPIO_SleepDDR R/W GPIO_SleepState R/W PWMA_Init R/W PWMB_Init R/W ADC_SampleIntvl R/W ADC0 ThresholdLo R/W 1 4 1 4 1 4 1 8 1 1 1 6 1 6 2 10 2 10 2 16 2 10 0 (all inputs) 0 (all zeros) 0x08 = use GPIO3 for RS485 enable GPIO messages disabled 0 = off; 1 = use sleep I/O states 0 (all inputs) 0 (all zeros) 0x0000 0x0000 0x0001 (10 ms) 0x0000 2008 by RF Monolithics, Inc. 33 M-0500-0000 Rev D DNT500 06 06 06 06 06 06 06 06 0F 11 13 15 17 19 1A 1E ADC0_ThresholdHi R/W ADC1_ThresholdLo R/W ADC1_ThresholdHi R/W ADC2_ThresholdLo R/W ADC2_ThresholdHi R/W IO_ReportEnable R/W IO_ReportInterval R/W IO_ReportAddress R/W 2 10 2 10 2 10 2 10 2 10 1 0..1 4 32 3 24 0x03FF 0x0000 0x03FF 0x0000 0x03FF 0 = off 0x00007530 (every 30,000 hops) 0x000000 GPIO_DIR This is a bitmask that sets whether the GPIOs are inputs (0) or outputs (1). The default is all inputs. GPIO_Init This is a bitmask that sets the initial value for any GPIOs which are enabled as outputs. For GPIOs enabled as inputs, this sets the initial pull-up setting. PWM0_Init This sets the initial value for PWM0 at startup. PWM1_Init This sets the initial value for PWM1 at startup. GPIO_Alt Provides and alternate function for GPIO3 as an RS-485 driver enable. GPIO_MessageMode This register enables a message to be sent to the base station whenever one of the GPIOs is triggered. If the radio is asleep, it will be awakened while the particular GPIO is as-

serted. Bit Option 7-6 Message type for GPIO_3 5-4 Message type for GPIO_2 3-2 Message type for GPIO_1 1-0 Message type for GPIO_0 Message options:

0b00: Disabled 0b01: Button Message Events are ignored and the radio is not awakened from sleep An event message is sent reporting the state of the corresponding GPIO input. The state will be 0b0 since I/Os are triggered on logic low. 2008 by RF Monolithics, Inc. 34 M-0500-0000 Rev D DNT500 0b10: Module I/O Message An event message is sent reporting the states of the entire I/O register bank 0b11: Registration Message A registration packet is sent to the base station. GPIO_SleepMode Enables setting of GPIOs to the designated direction and state whenever a device is asleep. GPIO_SleepDDR When GPIO_SleepMode is enabled, the three LSBs of this byte are used to set the direc-

tion of the GPIOs during a device's sleep period. This enables the user to provide alter-

nate configurations during sleep that will help minimize current consumption. Bits 0..2 correspond to GPIO0..GPIO2. GPIO_SleepState When GPIO_SleepMode is enabled, the three LSBs of this byte are used to set the output state of the GPIOs during a device's sleep period. This enables the user to provide alter-

nate configurations during sleep that will help minimize current consumption. Bits 0..2 correspond to GPIO0..GPIO2. ADC_SampleIntvl The ADC_SampleIntvl sets the interval between the beginning of one ADC read cycle and the next ADC read cycle. The three ADC inputs are read on each ADC read cycle. An ADC_SampleIntvl count equals 10 ms. ADC0..2_ThresholdLo/Hi These values define thresholds to trigger an I/O report based on ADC measurements. If I/O reporting is enabled, single EVENT report containing the contents of the I/O bank is generated when a threshold is crossed. Reporting is "edge-triggered" with respect to threshold boundaries, not "level-triggered"; i.e., if the measurement remains there, addi-

tional reports are not triggered until the value crosses the threshold again. The thresholds are met whenever one of the following inequalities are satisfied:

ADCx < ADCx_ThresholdLo ADCx > ADCx_ThresholdHi IO_ReportEnable When enabled, this causes a remote to periodically send an EVENT message to its base containing the contents of the I/O bank. IO_ReportInterval When periodic I/O reporting is enabled, this sets the interval between reports. The default is once every 30000 hops (every 5 minutes, at the default 10 ms hop duration). 2008 by RF Monolithics, Inc. 35 M-0500-0000 Rev D IO_ReportAddress Address to send I/O reports. Usually the base station address. 4.2.8 Bank FF - Special function DNT500 This bank contains two user functions, UcReset and MemorySave. Bank Loc'n R/W bytes Range Description Name FF 00 FF FF UcReset MemorySave W W 1 1 0..90 0..1 00 = reset, 1 = clear status/address and reset, 0x5A = reset with factory defaults 0 = load factory defaults, 1 = save settings to EEPROM UcReset Writing a value of 0x00 to this location forces a software reset of the microcontroller. Writing a value of 0x01 resets the Link Status and erases any assigned Network Address before resetting. Writing a value of 0x5A forces a factory default before resetting. Writ-

ing any other value returns an error. MemorySave Writing a zero to this location clears all registers back to factory defaults. Writing a one to this location commits the current register settings to EEPROM. When programming registers, all changes are considered temporary until this command is executed. 4.2.9 Protocol Mode Configuration/Sensor Message Examples 0xFB 0x05 0x04 0x18 0x00 0x01 0x03 For Example 5, the host configures the base station to transmit 24 dBm of RF power us-

ing the SetRegister command, 0x04. The TxPower parameter is stored in bank 0x00, reg-

ister 0x18. A one-byte parameter value of 0x03 selects the 24 dBm power level. The pro-

tocol formatting for the command is:

Note the order of the bytes in the command argument: register, bank, span, parameter value. When the base station receives the command it updates the parameter setting and return a SetRegisterReply message as follows:

In order for this new RF power setting to persist through a base station power down, MemorySave must be invoked. This is done by setting a one-byte parameter in register 0xFF of bank 0xFF to 0x01 with another SetRegister command:

The base station will write the current parameter values to EEPROM and return a SetReg-

isterReply message:

0xFB 0x05 0x04 0xFF 0xFF 0x01 0x01 0xFB 0x02 0x17 0x14 0xFB 0x01 0x14 2008 by RF Monolithics, Inc. 36 M-0500-0000 Rev D DNT500 For Example 6, the base station host requests an ADC1 reading from a remote using the GetRemoteRegister command, 0x0A. The MAC address of the remote is 0x000102. The current ADC1 measurement is read from register 0x07 in bank 0x05. The ADC reading spans two bytes. The protocol formatting for this command is:

0xFB 0x07 0x0A 0x02 0x01 0x00 0x07 0x05 0x02 Note the remote MAC address 0x000102 is entered in Little-Endian byte order, 0x02 0x01 0x00. The ADC reading is returned in a GetRemoteRegisterReply message:

0xFB 0x0B 0x1A 0x00 0x02 0x01 0x00 0x80 0x07 0x05 0x02 0xFF 0x02 Substantial information is returned in the message. The last two byes of the message give the ADC reading in Little-Endian format, 0xFF 0x02. The ADC reading is thus 0x02FF. The RSSI value is the byte following the address, 0x80. The TxStatus byte to the right of the GetRemoteRegisterReply Packet Type is 0x00, showing the packet was acknowledged on the RF channel. 4.2.10 Protocol Mode Event Message Examples For Example 4, input GPIO2 (only) is configured to initiate an event message on remote 0x000102. This is done by configuring one-byte parameter GPIO_MessageMode with a SetRemoteRegister command. GPIO_MessageMode is register 0x03 of bank 0x06. Bits 4-5 control GPIO2 event messaging. Button Message mode is chosen, which sends the state of GPIO2, located in register 0x02 of bank 0x05, when a high-to-low transition oc-

curs on GPIO2 (Button Message always reports a low state). The required GPIO_Mes-

sageMode bit pattern is 00010000b or 0x10. The protocol formatting for this command is:

0xFB 0x08 0x0B 0x02 0x01 0x00 0x03 0x06 0x01 0x10 The GPIO_MessageMode parameter is updated and SetRemoteRegisterReply is returned:

0xFB 0x06 0x1B 0x00 0x02 0x01 0x00 0x8F The RSSI value is the byte following the address, 0x8F. The TxStatus byte to the right of the GetRemoteRegisterReply Packet Type is 0x00, showing the packet was acknowledged on the RF channel. In order for this new GPIO_MessageMode setting to persist through a base station power down, MemorySave must be invoked, as discussed in Example 5. When a high-to-low button push transition occurs on GPIO2, remote 0x001002 will send the following RxEvent message to the base station host:

The message is output as a PktType 0x28 RxEvent. Note that the RSSI value 0x8E is in-

serted between the remotes MAC address and the register address byte. Register 0x02 in bank 0x05 uniquely identifies GPIO2 as the source of the event message. 0xFB 0x09 0x28 0x02 0x01 0x00 0x8E 0x02 0x05 0x01 0x00 2008 by RF Monolithics, Inc. 37 M-0500-0000 Rev D 5. DNT500 DEVELOPERS KIT Figure 5.1 shows the main contents of a DNT500DK Developers kit:

DNT500 Figure 5.1 5.1 DNT500DK Kit Contents The kit contains the following items:

Two DNT500P Radios Two DNT500 Interface Boards Two 9 V Wall Plug Power Suppliers, 120/240 VAC Two U.FL RF Jumper Cables Two RJ-45 to DB-9F Cable Assemblies Two A/B USB Cables One RJ-11 to DB-9F Cable Assembly Two 900 MHz Dipole Antennas One DNT500 Documentation and Software CD 5.2 Additional Items Needed To operate the kit, the following additional items are needed:

Two PCs with Microsoft Windows XP or Vista Operating System To fully test the kits functionality, the PCs should be equipped with high-speed serial ports capable of operation at 460.8 kb/s. 2008 by RF Monolithics, Inc. 38 M-0500-0000 Rev D DNT500 5.3 Developers Kit Default Operating Configuration The default operating configuration of the DNT500DK developers kit is TDMA Mode 2, point-to-point, with transparent serial data at 115.2 kb/s, 8N1. One DNT500P is precon-

figured as a base station and the other as a remote. The defaults can be overridden to test other operating configurations using the DNT500 Wizard utility discussed in Section 5.5. The default RF power setting is 10 dBm, which is suitable for side-by-side operation. The RF power level should be set higher as needed for longer range operation. Note that set-

ting the RF power to a high level when doing side-by-side testing will overload the DNT500P receiver and cause erratic operation. 5.4 Development Kit Hardware Assembly Observe ESD precautions when handling the kit circuit boards. Referring to Figure 5.4.1, confirm each DNT500P is correctly plugged into an interface board, with the radio ori-

ented so that its U.FL connector is next to the U.FL connector on the interface board. Check each radios alignment in the socket on the interface board. No pins should be hanging out over the ends of the connector. Next, install the U.FL jumper cables between the U.FL connectors on the radios and the interface boards. Then install the dipole anten-

nas. As shown in Figure 5.4.2, confirm there is a jumper on pins J14. The interface boards can now be powered by the 9 V wall plug transformer power supplies (the inter-

face boards can also be run for a short time from the 9 V batteries for range testing, etc.). Figure 5.4.1 2008 by RF Monolithics, Inc. 39 M-0500-0000 Rev D

 

 

DNT500 Figure 5.4.2 There are three serial connectors on the interface boards, as shown in Figure 5.4.3. The RJ-45 connector provides a high-speed RS232 interface to the DNT500Ps main serial port. The USB connector provides an optional interface to the radios main serial port. The RJ-11 connector provides a high-speed RS232 interface to the radios diagnostic port. The DNT500 Wizard utility program runs on the radios main port. Figure 5.4.3 2008 by RF Monolithics, Inc. 40 M-0500-0000 Rev D DNT500 The preferred PC interface is a serial port card capable of operating up to 460.8 kb/s. Many desktop PCs have a built-in serial port capable of operation at 115.2 kb/s. The kit can be run satisfactorily at the 115.2 kb/s data rate, but not at its fastest throughput. Use the RJ-45 to DB-9F cable assemblies for serial port operation. Optionally, the kit can be run from the USB port. Plugging in the USB cable automati-

cally switches operation from the RJ-45 connector. The USB interface is based on an FT232RL serial-to-USB converter IC manufactured by FTDI. The driver files for the FT232RL are located in the USB Driver folder on the kit CD, and the latest version of the driver can downloaded from the FTDI website, www.ftdichip.com. The driver creates a virtual COM port on the PC. Power up an interface board with an installed DNT500P us-

ing one of the supplied wall plug power supplies. Next connect the interface board to the PC with a USB cable. The PC will find the new USB hardware and open up a driver in-

stallation dialog box. Click on the Browse button in the dialog box and point to the folder with the FT232R driver files. The driver installation dialog will run twice to complete the FT232R driver installation. 5.5 DNT500 Wizard Utility Program The DNT500 Wizard utility program is located in the PC Programs folder on the kit CD. The Wizard requires no installation and can simply be copied to the PC and run. The Wizard start-up window is shown in Figure 5.5.1. Figure 5.5.1 Press the Connect button to open the serial port dialog box, as shown in Figure 5.5.2. Set the data rate to 115.2 kb/s (DNT500 default), select the COM port connected to the DNT500 interface board and press OK. 2008 by RF Monolithics, Inc. 41 M-0500-0000 Rev D DNT500 Figure 5.5.2 At this point the Wizard will collect configuration parameters from the DNT500. This data is organized under the first seven tabs, each corresponding to a Bank of register pa-

rameters as discussed in Section 4.2. The Transceiver Setup Tab as shown if Figure 5.5.3, and corresponds to Bank 0. The current values of each Bank 0 parameter are displayed and can be updated by selecting from the drop down menus or entering data from the keyboard, and then pressing the Apply button. Note that data is displayed and entered into the Wizard in Big-Endian order. The Wizard automatically reorders multi-byte data to and from Little-Endian order when building or interpreting protocol messages. In Figure 5.5.3 below, TX Power has been modified from its default value of 0 dBm to 18 dBm. Figure 5.5.3 In addition to conventional mouse and keyboard inputs, the Wizard supports two special function keys, F1 and F2. F1 toggles the serial port DTR line off and on. Pressing F1 the 2008 by RF Monolithics, Inc. 42 M-0500-0000 Rev D DNT500 first time after the Wizard is started will place the DNT500 in power down mode. Press-

ing the F1 key again will reboot and restart the DNT500. The current status of the DTR line is seen in the lower left corner of the Wizard window. F2 toggles the RTS line. Pressing F2 the first time after the Wizard is started will halt the flow of data from the DNT500. Pressing the F2 key again will re-enable data flow. The current status of the RTS line is also seen in the lower left corner of the Wizard window. Figure 5.5.4 shows the DNT500 Wizard System tab contents, corresponding to parameter Bank 1. The default parameters under this tab have been modified to change from CDMA to TDMA operation. Figure 5.5.4 2008 by RF Monolithics, Inc. 43 M-0500-0000 Rev D Figure 5.5.5 shows the DNT500 Wizard Status tab contents, corresponding to parameter Bank 2. Note the Status tab contains read-only parameters. DNT500 Figure 5.5.5 Figure 5.5.6 shows the DNT500 Wizard Serial tab contents corresponding to parameter Bank 3. The values shown below are the defaults for serial port operation. Figure 5.5.6 2008 by RF Monolithics, Inc. 44 M-0500-0000 Rev D Figure 5.5.7 shows the DNT500 Wizard Protocol tab contents, corresponding to parame-

ter Bank 4. Transparent data serial communication is currently chosen. DNT500 Figure 5.5.7 Figure 5.5.8 shows the DNT500 Wizard I/O Peripherals tab contents, corresponding to parameter Bank 5. GPIO ports 0 - 2 are logic high, GPIO port 3 is logic low. The 10-bit ADC inputs and PWM outputs are given in Big-Endian byte order. Figure 5.5.8 2008 by RF Monolithics, Inc. 45 M-0500-0000 Rev D DNT500 Figure 5.5.9 shows the DNT500 Wizard I/O Setup tab contents, corresponding to parame-

ter Bank 6. This tab allows the direction of the GPIO ports to be set both for active and sleep mode. The power-up initial values of the GPIO outputs can also be specified, and whether an input can generate a wake-up interrupt. GPIO event messaging and/or peri-

odic reporting and reporting interval can also be specified under this tab. The ADC sam-

pling interval and the high and low thresholds for event reporting on each ADC channel can be set, along with the start-up output values for each PWM (DAC) channel. Figure 5.5.9 Figure 5.5.10 shows the DNT500 Wizard RF Tests tab contents. A message placed in the Transmit Window is sent to the specified MAC address each time the Apply button is pressed. Messages received are displayed in the lower text box. The receive message text box can be cleared with the Clear button. Note that a base station will accept a message from a remote with the MAC address 0x000000 regardless of the base stations actual MAC address. 2008 by RF Monolithics, Inc. 46 M-0500-0000 Rev D

 

 

DNT500 5.6 DNT500 Interface Board Features Figure 5.5.10 The location of LEDs D1 through D4 and jumper pin sets J14 and J17 are shown in Fig-

ure 5.6.1. Figure 5.6.1 2008 by RF Monolithics, Inc. 47 M-0500-0000 Rev D DNT500 Amber DCD LED D4 illuminates on a remote to indicate it is registered with the base station and can participate in RF communications. LED D4 illuminates on the base sta-

tion when one or more remotes are registered to it. Green Activity LED D1 illuminates on a remote when transmitting data, and illuminates on a base when receiving data. Red Receive LED D3 illuminates when sending received data through the serial port to the PC. Green Transmit LED D2 illuminates when the PC sends data through the serial port to be transmitted. Jumper pin set J14 is provided to allow measurement of the DNT500P current. For nor-

mal operation J14 has a shorting plug installed. Jumper pin set J17 allows the DNT500P CFG pin to be grounded by installing a shorting plug. This places the DNT500P in proto-

col mode. Figure 5.6.2 Figure 5.6.2 shows the connectors to the right of the DNT500P mounting socket. Jumper pin set J9 allow the DNT500P reset line to be routed to JTAG interface connector J10. J18 allows the DNT500P reset line to be grounded. Note that the JTAG operation is usu-

ally limited to factory testing. For normal operation pin sets J9 and J18 should not have a shorting block installed. Jumper pin sets J12 and J13 normally have shorting plugs in-

stalled as shown in Figure 5.6.2, which connects the DNT500P UART0_TXD and UART0_RXD pins to the respective serial data lines on the evaluation board. It is possi-

ble to connect directly to UART0_TXD and UART0_RXD by moving the jumpers over. In this case, J11-1 is the input for transmitted data and J11-2 is the output for received data. Note this a 3 V logic interface. Placing a shorting plug on jumper pin set J6 allows 2008 by RF Monolithics, Inc. 48 M-0500-0000 Rev D DNT500 the DNT500P to be powered up in boot loader mode. This is used for factory code loads and functional testing. The DNT500 has its own boot loader utility that allows the proto-

col firmware to be installed with a terminal program that supports YMODEM. Pin strip J7 provides access to various DNT500 pins as shown on the silkscreen. Pressing switch SW2 will reset the DNT500P. Figure 5.6.3 Figure 5.6.3 shows the connectors to the left of the DNT500P mounting socket. Pressing switch SW2 switches GPIO0 from logic high to logic low. Pin strip J8 provides access to various DNT500 pins as shown on the silkscreen. The wiper of pot R10 drives the input of ADC1. Clockwise rotation of the pot wiper increases the voltage. Thermistor RT1 is part of a voltage divider that drives ADC0. LED D5 illuminates when GPIO1 is set as a logic high output. LED D10 illuminates when GPIO3 is set as a logic high. The DNT500P interface board includes a 5 V regulator to regulate the input from the 9 V wall transformer power supply. Note: do not attempt to use the 9 V wall transformer power supply to power the DNT500P directly. The maximum allowed voltage input to the DNT500P is 5.5 V. 2008 by RF Monolithics, Inc. 49 M-0500-0000 Rev D DNT500 6. Demonstration Procedure The procedure below provides a quick demonstration of the DNT500 using a DNT500DK development kit:

1. Confirm that each DNT500P is installed correctly in an interface board, and that the U.FL jumpers between the DNT500P radios and the interface boards are in-

stalled. Also confirm that a dipole antenna is installed on each interface board, and that J14 has a jumper block installed on each interface board. See Figures 5.4.1, 5.4.2 and 5.4.3 above. 2. Attach each transceiver/interface board to a computer with the DNT500 Wizard utility program installed. Place the transceivers at least 3 feet (one meter) apart. 3. Start the DNT500 Wizard utility program on both computers. 4. On each computer, press the Connect button on the Wizard window. This will open a serial port setup dialog box. Set the baud rate to 115.2 kb/s and select the COM port the DNT500 is connected to. Parameter values on the left of the Wiz-

ard main window and on the Transceiver Setup tab will fill in. 5. Select the RF Test tab on the Wizard. A message placed in the Transmit Window is sent to the specified MAC address each time the Apply button is pressed. Mes-

sages received are displayed in the lower text box. The receive message text box can be cleared with the Clear button. 2008 by RF Monolithics, Inc. 50 M-0500-0000 Rev D 7. Troubleshooting DNT500 DNT500 not responding:

Make sure DTR is asserted (logic low) to bring the radio out of sleep mode. Cannot enter protocol mode:

Make sure the host data rate is correct. The DNT500 defaults to 115.2 kb/s. If using the escape sequence command, make sure a pause of at least 20 ms precedes the escape se-

quence. A remote never detects carrier (DCD):

Check that the base station is running, and that the remote InitialNwkID parameter is the same as the base station, or is set to 0xFF. Also check that remote is receiving an ade-

quate signal from the base station. Carrier is detected, but no data appears to be received:

Make sure that RTS is asserted to enable receive character flow. Make sure the RF transmit power is not on a high settings if the nodes are close together. The DNT500 is interfering with other nearby circuits:

It is possible for the RF energy from the DNT500 to be rectified by nearby circuits that are not shielded for RF, manifesting as a lower frequency pulse noise signal. If possible, place the antenna at least 1 foot away from the transceiver module, and 3 feet from other system circuit boards. Place sensitive circuits in a grounded metal casing to keep out RFI. Range is extremely limited:

This is usually a sign of a poor antenna connection or the wrong antenna. Check that the antenna is firmly connected. If possible, remove any obstructions in the near field of the antenna (nominal 3 ft radius). Transmitting terminal flashes (drops) CTS occasionally:

This indicates that the transmitter is unable to reliably get its data across. This may be the result of an interfering signal, but most often is caused by overloading of the network. Adjusting the protocol parameters may increase the network efficiency. Receiving terminal drops characters periodically:

Set the number of retries to a high number and send a few characters. Check that the transmitted data can get through under these conditions. Sometimes this symptom is caused by an application that is explicitly dependent on the timing of the received data stream. The nature of the RF channel imposes a degree of unpredictability in the end-to-

end transmission delay. 2008 by RF Monolithics, Inc. 51 M-0500-0000 Rev D DNT500 8. APPENDICES 8.1 Ordering Information DNT500 OEM Transceiver Module (solder pad mounting) DNT500P OEM Transceiver Module (pin-socket mounting) 8.2 Technical Support For DNT500 technical support call RFM at (678) 684-2000 between the hours of 8:30AM and 5:30PM Eastern Time. 2008 by RF Monolithics, Inc. 52 M-0500-0000 Rev D 8.3 DNT500 Mechanical Specifications DNT500 2008 Cirronet Inc 53 M-0500-0000 Rev B

6

K J

E

A

K

J E

C

, E

A

I E

I

, E

A

I E

I

E

E

D A I

6

2

K J

E

A

K

J E

C

, E

A

I E

I

, E

A

I E

I

E

E

D A I

DNT500 2008 Cirronet Inc 54 M-0500-0000 Rev B

6

2

1

J A H B

A

A

J

H 2

O

K J

, A J

E

A

J

H I

H A

1

A

J H

E

I

H

A G K E L

A

J

, E

A

I E

I

E

E

D A I

E

E

K

F

J A

2

D

A

E

A J A H

DNT500 9. Warranty Seller warrants solely to Buyer that the goods delivered hereunder shall be free from de-

fects in materials and workmanship, when given normal, proper and intended usage, for twelve (12) months from the date of delivery to Buyer. Seller agrees to repair or replace at its option and without cost to Buyer all defective goods sold hereunder, provided that Buyer has given Seller written notice of such warranty claim within such warranty period. All goods returned to Seller for repair or replacement must be sent freight prepaid to Sellers plant, provided that Buyer first obtain from Seller a Return Goods Authorization before any such return. Seller shall have no obligation to make repairs or replacements which are required by normal wear and tear, or which result, in whole or in part, from ca-

tastrophe, fault or negligence of Buyer, or from improper or unauthorized use of the goods, or use of the goods in a manner for which they are not designed, or by causes ex-

ternal to the goods such as, but not limited to, power failure. No suit or action shall be brought against Seller more than twelve (12) months after the related cause of action has occurred. Buyer has not relied and shall not rely on any oral representation regarding the goods sold hereunder, and any oral representation shall not bind Seller and shall not be a part of any warranty. THE PROVISIONS OF THE FOREGOING WARRANTY ARE IN LIEU OF ANY OTHER WARRANTY, WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL (INCLUDING ANY WARRANTY OR MERCHANT ABILITY OR FITNESS FOR A PARTICULAR PURPOSE). SELLERS LIABILITY ARISING OUT OF THE MANUFACTURE, SALE OR SUPPLYING OF THE GOODS OR THEIR USE OR DISPOSITION, WHETHER BASED UPON WARRANTY, CONTRACT, TORT OR OTHERWISE, SHALL NOT EXCEED THE ACTUAL PURCHASE PRICE PAID BY BUYER FOR THE GOODS. IN NO EVENT SHALL SELLER BE LIABLE TO BUYER OR ANY OTHER PERSON OR ENTITY FOR SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING, BUT NOT LIMITED TO, LOSS OF PROFITS, LOSS OF DATA OR LOSS OF USE DAMAGES ARISING OUT OF THE MANUFACTURE, SALE OR SUPPLYING OF THE GOODS. THE FOREGOING WARRANTY EXTENDS TO BUYER ONLY AND SHALL NOT BE APPLICABLE TO ANY OTHER PERSON OR ENTITY INCLUDING, WITHOUT LIMITATION, CUSTOMERS OF BUYERS. 2008 Cirronet Inc 55 M-0500-0000 Rev B