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Page 13 of 90

CCT24

Figure 2.10.1

2.10.1  Polling Mode

Polling channel access is used for point-to-point and point-to-multipoint systems where only one remote
will attempt to transmit data at a time, usually in response to a command from the base.

Polling (mode 0) is a special case of CSMA mode 1. The user can set the

BaseSlotSize

and

CSMA_

RemtSlotSize

parameters when using this mode. Since only one remote will attempt to transmit at a time,

to minimize latency, the

CSMA_Predelay

and

CSMA_Backoff

parameters are not used. Lease renewals

are also not used, again to minimize latency. Thus, when the base is operated in protocol mode with
Announce messages enabled, only join messages are generated. This mode provides high throughput as
there is no contention between remotes and the entire portion of the hop frame following the base trans-
mission is available for a remote to transmit. Applications where more than one remote may attempt to
transmit at a time, where event and/or periodic I/O reporting are enabled, and/or tree-routing operation is
required should not use this mode.

2.10.2 CSMA Mode

When using CSMA channel access, each remote/router with data to send listens to see if the channel is
clear and then transmits. If the channel is not clear, a radio will wait a random period of time and listen
again. CSMA works best when a large or variable number of radios transmit infrequent bursts of data.
There is no absolute upper limit on the number of radios that can be supported in this mode - it depends
on message density. A maximum of 126 radios can be supported if base-managed join/leave tracking is
required, or an unlimited number of remotes if base join-leave tracking is not required or will be handled
by the host application.

There are two important parameters related to CSMA operation. The

CSMA_Backoff

parameter defines

the initial time that a radio will wait when it determines the channel is busy before again checking to see if
the channel is clear (back-off interval). If, after finding the channel busy and backing off, the radio finds

Summary of Contents for CCT24 Series

Page 1: ...Page 1 of 90 CCT24 CCT24 Series 2 4 GHz Spread Spectrum Wireless Transceivers Integration Guide ...

Page 2: ...RFM could void the user s authority to operate the equipment RF Exposure Information For mobile operating conditions 20 cm to the body This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment This equipment should be installed and operated with minimum distance 20 cm between the radiator and your body This transmitter must not be co located or operating ...

Page 3: ...olling Mode 13 2 10 2 CSMA Mode 13 2 10 3 TDMA Modes 14 2 11 Transmission Configuration Planning 15 2 11 1 TDMA Throughput 15 2 11 2 Polling Throughput 16 2 11 3 CSMA Throughput 16 2 11 4 Latency 17 2 11 5 Configuration Validation 18 2 12 Tree Routing Systems 20 2 12 1 Example Tree Routing System 20 2 12 2 Tree Routing System Networks 22 2 12 3 Tree Routing System Addressing 22 2 12 4 Tree Routing...

Page 4: ...tive Router ID Table 59 4 2 10 Bank 9 Registered MAC Addresses 59 4 2 11 Bank FF Special Functions 60 4 2 12 Protocol Mode Configuration Example 61 4 2 13 Protocol Mode Sensor Message Example 61 4 2 14 Protocol Mode Event Message Example 61 5 0 CCT24DK Developer s Kit 62 5 1 CCT24DK Kit Contents 62 5 2 Additional Items Needed 62 5 3 Developer s Kit Operational Notes 62 5 4 Developer s Kit Default ...

Page 5: ...tocol with data buffering ensures data integrity Simple interface handles both data and control at up to 460 8 kb s on the serial port or 80 64 kb s on the SPI port Analog and digital I O simplifies wireless sensing Auto reporting I O mode simplifies applica tion development 1 1 Why Spread Spectrum A radio channel can be very hostile corrupted by noise path loss and interfering transmissions from ...

Page 6: ...e transmitted data stream by a much faster noise like repeating pattern The ratio by which this modulating pattern exceeds the bit rate of the base band data is called the processing gain and is equal to the amount of rejection the system affords against narrow band interference from multipath and jammers Transmitting the data signal as usual but varying the carrier frequency rapidly according to ...

Page 7: ...adios in the network to receive the transmission they must be listening to the frequency on which the current transmission is being sent To do this all the radios in the network must be synchronized to the same hopping pattern In all CCT24 networks one radio is designated as the base All other radios are designated as remotes or routers The base transmits a beacon each time it hops to a different ...

Page 8: ...ort larger networks mode 2 must be used When the AuthMode parameter is set to 2 the address of a radio attempting to register with the base is sent to the host for authentication in a JoinRequest message The host application determines if the radio should be allowed to register and returns a JoinReply message to the base containing a PermitStatus parameter that allows or blocks the radio from regi...

Page 9: ...to values greater than their defaults in point to multipoint systems where some or all the remotes are in transparent mode 2 4 SPI Port Modes CCT24 radios can be configured to transmit and receive data through the serial peripheral interface SPI port instead of the primary serial UART port A CCT24 can operate as either an SPI Master or Slave Messages routed through the SPI port must be protocol fo...

Page 10: ...level set by the TxPower parameter Remotes and routers automatically adjust their transmitter power to deliver packets to the base at an adequate but not excessive signal level while not transmitting more power than set by their TxPower parameter Remotes and routers make transmitter power adjustments using the strength of the signals received from the base and the base transmitter power setting wh...

Page 11: ... tions running on each remote can determine the data s destination from the data itself Protocol formatting adds addressing and other overhead bytes to the user data If the addressed remote is using transparent formatting the source originator address and the other overhead bytes are removed If the remote is using protocol formatting the source address and the other overhead bytes are output with ...

Page 12: ...ning of each hop followed by its user data After the base transmission the remotes routers can transmit Each trans mission may contain all or part of a complete message from its host application From an application s perspective the radios are communicating in full duplex since the base can receive data from a re mote router before it completes the transmission of a message to the remote router an...

Page 13: ...ay attempt to transmit at a time where event and or periodic I O reporting are enabled and or tree routing operation is required should not use this mode 2 10 2 CSMA Mode When using CSMA channel access each remote router with data to send listens to see if the channel is clear and then transmits If the channel is not clear a radio will wait a random period of time and listen again CSMA works best ...

Page 14: ...ages to its host when a remote joins and when the remote s registration lease expires While a base in a CSMA network can track a maximum of 126 remotes entering and leaving the network it can generate join Announce messages for an unlimited number of remotes This allows the host appli cation to track remotes entering and leaving a CSMA network with more than 126 remotes by creating its own table o...

Page 15: ... user must configure PTT remotes individually to select mode 4 operation The user s application must ensure that only one PTT remote at a time is using the slot Mode 4 does not support tree routing operation 2 11 Transmission Configuration Planning Because frequency hopping radios change frequency periodically a single message may be sent in one or more RF transmissions The length of time the radi...

Page 16: ...rameters Sending 160 bits at 38 4 kb s takes 4 2 ms Add 1 ms for the host device to process the command and begin sending the 32 byte response The 32 byte response takes 8 4 ms to send at 38 4 kb s for a total turnaround time of 13 6 ms This amount of time could be added to the base and remote slot times to allow the entire transaction to take place in a single hop However except at the 38 4 kb s ...

Page 17: ... detects that the channel is busy it will increase the amount of time it waits until it checks again Every subsequent time it detects a busy channel it will in crease the amount of time it will wait in a geometric fashion This continues until it detects an idle chan nel So while a short CSMA_Backoff can decrease the time between when one remote transmits and the next remote transmits it can actual...

Page 18: ...ameters are usually set to accommodate the number of data bytes in a maximum size transmission This con figuration provides low latency for polled messages 5 When operating in CSMA mode 1 with multiple remotes the CSMA_RemtSlotSize and HopDura tion parameters are usually set to accommodate three times the number of data bytes in one maximum size transmission to allow time for more than one remote ...

Page 19: ...m number of data bytes in a transmission Next determine the RemoteSlotSize required to accommodate the maximum number of data bytes in a remote transmission Then set the number of remote slots Use the slot sizes the number of remotes the RF data rate and maximum operating range as inputs to the Calculator to determine the minimum valid hop duration TDMA PTT mode 4 use the same procedure as for TDM...

Page 20: ... R3 and R6 have direct communi cations with either R2 or R5 both of which have direct communications with the base radio R7 has direct communications with R6 and can use R6 to route messages to and from the base through R5 Using the tree routing function of the CCT24 all nodes will be able to send and receive data to and from the centrally located base R2 R5 and R6 which are configured to relay da...

Page 21: ...he same tree routing ID and have tree routing option enabled In addition R2 R5 and R6 must be assigned individual BaseModeNetID parameters and then configured for router operation The network IDs and network addresses will be automatically assigned as the system forms Figure 2 12 1 2 shows one way that the network IDs and system addresses could be assigned Note that the routing nodes R2 R5 and R6 ...

Page 22: ...C addresses tree routing system addresses contain three bytes However the most significant byte of a system address is currently unused and can be assigned any value typically 0xFF The middle byte of a system address is the network ID or NwkID of a base or router The NwkID is always 0x00 for the base and will have a value in the range of 0x01 to 0x3F for a router The least significant byte of the ...

Page 23: ...follows 0xFF NwkID NwkAddr 2 12 4 Tree Routing System Implementation Options There are three ways to assign parent network IDs and system addresses to the routers and remotes in a tree routing system dynamic router parent and remote system address assignment manual router parent assignment with dynamic remote address assignment and manual router parent and remote address assignment Dynamic router ...

Page 24: ... 0x3F specifies parent 0x01 0x7E sent to parent 0x01 0x3F router NwkID Remote 0x00 0x3F specifies parent 0x01 0x07 sent to parent 0xFF not used by remote Table 2 12 4 1 Tree routing networks can support peer to peer communications However the value of the P2PReply Timeout parameter see Section 4 2 2 is interpreted differently in a tree routing system compared to a point to multipoint network In a ...

Page 25: ...84 0 2604 57 6 5 76 0 1736 76 8 7 68 0 1302 115 2 11 52 0 0868 230 4 23 04 0 0434 460 8 46 08 0 0217 Table 2 13 1 To support continuous full duplex serial port data flow an RF data rate higher than the serial port baud rate is required for FHSS Radios transmissions are half duplex and there are overheads related to hopping frequencies assembling packets from the serial port data stream transmittin...

Page 26: ... to time SPI Select SS sampling etc Where possible devices connected to the CCT24 SPI port should be configured to match the 80 64 kb s data rate In any event the SPI data rate used by the CCT24 and the connected device should be matched within a few percent for efficient data transfers SPI port operation is full duplex in the sense that a single clock signal simultaneously shifts data into and ou...

Page 27: ...and out of the SPI port remain byte framed Less frequent SS line toggling is also acceptable in most applications It is recommended that SS be toggled at the start and end of each transmit message and after every 256 null bytes when clocking to output a received message The SS line should also be toggled at the end of each received message Figure 2 14 4 shows the signals a CCT24 uses in SPI Master...

Page 28: ... cessful it will scan and record the entire broadcast system parameter list before it goes back to sleep Otherwise in order to conserve battery life a sleeping remote will update any values that it may hear while it is awake but is not required to listen to the entire list If a remote is linking for the first time or if its last attempt to acquire and synchronize was unsuc cessful it will send a r...

Page 29: ...e the remote will remain awake The remote will remain awake while it still has any ARQ attempts left for a queued transmit pack et of any type The remote will remain awake while it is has serial characters in its buffer left to transmit to its local host Sleep functions are controlled by the following registers see Section 4 2 SleepMode enables disables sleep mode WakeResponseTime sets the amount ...

Page 30: ...nged but it cannot be read back 2 17 Synchronizing Co located Bases The EX_SYNC input Pin 15 on the CCT24 allows co located bases to synchronize their transmissions so they all transmit at the same time This prevents the situation where one base is transmitting while another nearby base is trying to hear a distant remote Even though the base radios may be on different frequencies because of their ...

Page 31: ...ent to reset all base patterns to their first frequency following the reset or power up of any of the co located bases Thereafter a cycle of N 1 narrow pulses and then 1 wide pulse should be sent where N is the number of frequencies in the subband being used For example if the frequency subband contains 15 frequencies a repeating cycle containing 1 wide pulse followed by 14 nar row pulses should b...

Page 32: ...iciency transmitter amplifier providing excellent range in outdoor applications The CCT24 provides a variety of hardware interfaces There are two serial ports plus one SPI port Either the primary serial port or the SPI port can be selected for data communications The second serial port is dedicated to diagnostics The primary and diagnostic serial ports support standard baud rates up to 460 8 kb s ...

Page 33: ...bits Signal Source Impedance for ADC Reading 10 KΩ PWM DAC Output Range 0 3 3 V PWM DAC Output Resolution 8 bits PWM Output Period 20 µs Primary and Diagnostic Serial Port Baud Rates 1 2 2 4 4 8 9 6 19 2 28 8 38 4 57 6 76 8 115 2 230 4 460 8 kb s Serial Peripheral Interface Data Rate 6 35 80 64 kb s Digital I O Logic Low Input Level 0 5 0 8 V Logic High Input Level 2 3 3 V Power Supply Voltage Ran...

Page 34: ...z 3 dB BW 10 PWM1 O 8 bit pulse width modulated output 1 with internal low pass filter Filter is 1st order 159 Hz 3 dB BW 11 SLEEP DTR I Default functionality is active high module sleep input active low DTR When switched low after sleep the module executes a power on reset Usually connected to host DTR 12 ADC2 I 10 bit ADC input 0 Full scale reading is referenced to the ADC_REF input 13 ADC1 I 10...

Page 35: ...s 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 35 SS SPI active low slave select This pin is an output when the CCT24 operating as a master and an input when it is operating as a slave 36 MOSI SPI master out slave in function This pin is an output when the CCT24 is operatin...

Page 36: ...de 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 Signals applied to the analog inputs must be in the range of 0 to ADC_REF Pad Pin 3 Applying a voltage to a logic or analog input outside of its operating range can damage the CCT24 module 3 5 ESD and Transient ...

Page 37: ...owing Contains FCC ID HSW CCT24 Contains IC 4492A CCT24 Notices 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 user s authority to operate this device FCC NOTICE This device complies with Part 15 of the FCC rules Operation is subject to the following two conditions 1 this device may not cause harmful inte...

Page 38: ...cluded in this list or having a gain greater than the maximum gain indicated for that type are strictly prohibited for use with this device Le présent émetteur radio identifier le dispositif par son numéro de certification ou son numéro de modèle s il fait partie du matériel de catégorie I a été approuvé par Industrie Canada pour fonctionner avec les types d antenne énumérés ci dessous et ayant un...

Page 39: ...age and whether it is a message sent from the host or is a reply from the radio see Table 4 1 2 1 below 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 ...

Page 40: ...lds 0x28 RxEvent from Radio Addr RSSI Reg Bank Span Val 0x0A GetRemoteRegister from Host Addr Reg Bank Span 0x1A GetRemoteRegisterReply from Radio If command successful TxStatus Addr RSSI Reg Bank Span Val If command failed TxStatus Addr 0x0B SetRemoteRegister from Host Addr Reg Bank Span Val 0x1B SetRemoteRegisterReply from Radio TxStatus Addr RSSI 0x2C JoinRequest from Radio MacAddr Addr DeviceM...

Page 41: ...has completed startup initialization none 0xA2 Base a child has joined the network MacAddr Reserved Range 0xA3 Remote joined a network ready for data NwkID BaseMacAddr Range 0xA4 Remote exited network base is out of range NwkID 0xA5 Remote the base has rebooted none 0xA7 Base remote has left the network MacAddr 0xA8 Base heartbeat received from router or remote MacAddr NwkAddr NwkID ParentNwkID Be...

Page 42: ...01 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 outputs a TxDataReply message to its host 0xFB 0x06 0x15 0x00 0x02 0x01 0x00 0xC4 The 0x00 TxStatus byte...

Page 43: ... auto 00 02 HopDuration R W 2 4 4000 10 ms 0x00C8 00 04 InitialParent NwkID R W 1 0 255 0xFF join any network 00 05 SecurityKey R W 16 0 2128 all null bytes 0x00 security disabled 00 15 SleepMode R W 1 0 1 0 off 1 on 2 on after reset 00 16 WakeResponseTime R W 1 0 255 1 50 ms 0 to disable 00 17 WakeLinkTimeout R W 1 0 255 5 s 00 18 TxPower R W 1 0 2 0 1 mW 1 10 mW 2 63 mW 00 19 ExtSyncEnable R W 1...

Page 44: ...ing system networks with the same hopping pattern must be physically separated by enough distance that they cannot receive transmissions from each other It is often convenient to set the InitialParentNwkID parameter value on remotes to 0xFF to allow them to connect to any parent device However setting the InitialParentNwkID parameter value to 0xFF on a system with a large number of routers can be ...

Page 45: ...location description or other identifying tag such as a friendly name RegDenialDelay when a remote has been removed from a network through a RemoteLeave the RegDenialDelay parameter sets the length of time the remote will wait before considering that network a candidate for joining again Units are in seconds the default is 10 s RmtTransDestAddr this parameter sets the destination address that a re...

Page 46: ...k conges tion causing heartbeats from routers to be delayed or lost The base treats router heartbeat packets differently than remote heartbeat packets Heartbeat packets from remotes are not ACKed while ACKs are sent to a routers originating a heartbeat packets to indicate reception This prevents additional heartbeat transmissions by a router until the next heartbeat interval If a router does not r...

Page 47: ...t be set by the user for all access modes The default value is 50 bytes LeasePeriod this sets the duration in seconds for leases that remotes receive from the base If a period of zero is specified then lease functions are disabled The minimum valid lease period is two seconds Remotes will attempt to renew their leases at an interval equal to half the lease period For example if the lease period is...

Page 48: ... their slot timing calculations in units of 3 1 µs This is used to increase the amount of time dedicated to the regis tration slot Increasing this value will subtract slightly from the overall slot time available to remotes for sending data Note that the free space round trip propagation delay for one mile is 10 72 µs Each incre ment of MaxPropDelay thus corresponds to a maximum radius from the re...

Page 49: ...artbeat interval in seconds is less than the P2PReplyTimeout in hop pairs it is possi ble that a router will not repeat an un ACKed heartbeat packet quickly enough to prevent the base from timing that router out heartbeats are repeated only when an ACK is not received within the P2PReplyTimeout interval Thus setting the P2PReplyTimeout to a very large value relative to the heartbeat interval could...

Page 50: ...l be discarded In the three TDMA modes the remote slot size is automatically computed and this value is read only In polling and CSMA modes the remote slot size must be set by the user The parameter to set this is CSMA_RemtSlotSize in Bank 1 TDMA_NumSlots in TDMA access modes this returns the number of slots currently allocated TDMA_CurrSlot returns the current TDMA slot number assigned to the rem...

Page 51: ...bytes Range Default 0x03 0x00 SerialRate R W 2 1 384 0x0030 9 6 kb s 0x03 0x02 SerialParams R W 1 0 7 0x00 8N1 0x03 0x03 SerialControls R W 1 0 7 0X07 0x03 0x04 SPI_Mode R W 1 0 2 0x00 SPI disabled 0x03 0x05 SPI_Divisor R W 1 1 27 0x0A 80 64 kb s 0x03 0x06 SPI_Options R W 1 0 3 0x00 standard SPI configuration 0x03 0x07 SPI_MasterCmdLen R W 1 0 25 0x00 0x03 0x08 SPI_MasterCmdStr R W 32 ASCII all 0x...

Page 52: ...r mode When a CCT24 is configured for SPI Slave mode operation all messages are routed through the SPI port in lieu of the primary serial UART port The HOST_CTS signal provides the same flow control function for the MOSI input that it provides for the RADIO_RXD serial input The Master host can clock transmit messages into the CCT24 SPI Slave whenever HOST_CTS is set to a logic low state The Master...

Page 53: ...ts SS high after clocking the last message bit When the CCT24 is operating in SPI Slave mode the Master host must set SS low at least one SPI bit period before clocking data in out of the CCT24 See the SPI_Divisor description below Changes to the SPI_Mode setting must be saved and the CCT24 reset to take effect This avoids the possibility of setting SPI mode inadvertently and being unable to commu...

Page 54: ...ferred for new designs It is not necessary to define the same protocol mode for all radios 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 transmitting an Enter ProtocolMode command ProtocolOptions ...

Page 55: ...on each frequency hop The default value is 3 the range is 1 to 3 4 2 6 Bank 5 I O Peripheral Registers Size in Range Bank Loc n Name R W bytes in bits Default 0x05 0x00 GPIO0 R W 1 1 0 0x05 0x01 GPIO1 R W 1 1 0 0x05 0x02 GPIO2 R W 1 1 0 0x05 0x03 GPIO3 R W 1 1 0 0x05 0x04 GPIO4 R W 1 1 0 0x05 0x05 GPIO5 R W 1 1 0 0x05 0x06 ADC0 R 2 10 N A 0x05 0x08 ADC1 R 2 10 N A 0x05 0x0A ADC2 R 2 10 N A 0x05 0x...

Page 56: ...his parameter is a bitmask that sets the initial value for any GPIOs which are enabled as outputs GPIO_Alt this parameter is a bitmask to select alternate functions for GPIO3 GPIO4 and GPIO5 as shown below Bit Alternate function 3 GPIO3 functions as an RS 485 driver enable output 4 GPIO4 functions as an SPI_RX_AVL SPI RX data available flag 5 GPIO5 functions as an antenna diversity control output ...

Page 57: ...e increased PWM0_Init this parameter sets the initial value for PWM0 at startup PWM1_Init this parameter sets the initial value for PWM1 at startup ADC_SampleIntvl this parameter 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 Each ADC_SampleIntvl count equals 10 ms This interval will be the worst case l...

Page 58: ... ApprovedAddr11 R W 3 0x07 0x24 ApprovedAddr12 R W 3 0x07 0x27 ApprovedAddr13 R W 3 0x07 0x2A ApprovedAddr14 R W 3 0x07 0x2D ApprovedAddr15 R W 3 ApprovedAdd0 15 the three byte parameters in Bank 7 are the MAC addresses of the remotes author ized to join the network The addresses are entered in little endian format such that a radio with MAC address 012345 would be entered 0x452301 4 2 9 Bank 8 Tr...

Page 59: ...of the microcontroller This will enable those changes which require a reset If this is written to before 0x01 is written to the MemorySave parameter the last parameter values saved before the reset will be in effect A reply packet either local or over the air may not be received when writing a value to this register Writing 0x5A to this location will reset the radio and load the factory default se...

Page 60: ... In order for this new RF power setting to persist through a base 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 0xFB 0x05 0x04 0xFF 0xFF 0x01 0x01 The base will write the current parameter values to EEPROM and return a SetRegisterReply message 0xFB 0x01 0x14 4 2 13 Protocol Mode Sensor Messa...

Page 61: ...o is 0xFB 0x08 0x0B 0x56 0x34 0x12 0x19 0x06 0x01 0x10 The periodic report timer bit in IO_ReportTrigger is located in bit position four 00010000b or 0x10 The IO_ReportTrigger parameter is updated and SetRemoteRegisterReply is returned 0xFB 0x06 0x1B 0x00 0x56 0x34 0x12 0xC4 The remote will start sending event messages on 10 second intervals as shown in the log records below FB 16 28 56 34 12 CB 0...

Page 62: ...24DK documentation and software CD 5 2 Additional Items Needed To operate the kit the following additional items are needed One PC with Microsoft Windows XP or Vista Operating System The PC must be equipped with a USB port or a serial port capable of operation at 9 6 kb s 5 3 Developer s Kit Operational Notes CCT24DK kits are preconfigured to run at a 500 kb s RF data rate with 1 mW of RF transmit...

Page 63: ...or longer range operation Note that setting the RF power to a high level when doing testing at 2 m can overload the CCT24 receiver and cause erratic operation See Section 5 3 5 5 Developer s Kit Hardware Assembly Observe ESD precautions when handling the kit circuit boards The components that make up a devel opment board are shipped with the CCT24 radios and U FL coax jumper cables installed in th...

Page 64: ...f 90 CCT24 As shown in Figure 5 5 1 there is a jumper on pins J14 This jumper can be removed and a current meter connected across J14 to measure just the CCT24 s current consumption during operation Figure 5 5 1 ...

Page 65: ...an FT232RL serial to USB converter IC manufactured by FTDI The FT232RL driver files are located in the i386 and AMD64 folders on the kit CD and the latest version of the drivers can downloaded from the FTDI website www ftdichip com The drivers create a virtual COM port on the PC Power the Base using one of the supplied wall plug power supplies Next connect the Base to the PC with a USB cable The P...

Page 66: ...of operating at 9 6 kb s or faster As discussed above the USB interface can also be used Connect the Base to the PC and power up the Base and the Remote development boards using the wall plug power supplies The DNT Demo utility program is located in the PC Programs folder The DNT Demo requires no installation and can be simply copied to the PC and run Start the DNT Demo on the PC The start up wind...

Page 67: ...board labeled Ext_TX and Ext_RX to connect the center and right header pins This disconnects the module s TX and RX pins from the USB and RS 232C circuits Use a banana clip or other short jumper to connect together the two pins on the header labeled J11 Ext_MICRO Attempting loop back testing by connecting Pins 2 and 3 of the DB9 serial connector can cause erratic behavior due to noise coupling fro...

Page 68: ...ted MAC Address Note that the MAC address a remote uses for the base is always 0x000000 Data sent to the local radio is displayed in the Received Data text box Received data can be displayed as ASCII default or in Hexadecimal format by checking the Hex Mode check box When the Transmit Interval is set to zero Data to Transmit is sent once when the Transmit button is clicked When the Transmit Interv...

Page 69: ...b corresponding to Bank 9 Figure 5 6 2 2 The Transceiver Setup Tab is shown in Figure 5 6 2 2 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 Changes button Note that data is displayed and entered in Big Endian order The Demo automatically reor...

Page 70: ...y except for ARQ_Mode which applies to both the base and the remotes Figure 5 6 2 4 Figure 5 6 2 4 shows the Status tab contents corresponding to Bank 2 Note the Status tab contains read only parameters Figure 5 6 2 5 Figure 5 6 2 5 shows the Serial tab contents corresponding to Bank 3 The values shown are the defaults for serial port operation ...

Page 71: ... munication is currently chosen Figure 5 6 2 7 Figure 5 6 2 7 shows the I O Peripherals tab contents corresponding to Bank 5 GPIO ports 1 through 5 are logic low GPIO port 0 is logic high The 10 bit ADC input readings and PWM output settings are given in Big Endian byte order Event flags are presented on the right side of the window ...

Page 72: ...rupt trigger is selected from the drop down boxes to the right of the check boxes GPIO alternate function periodic I O reporting reporting interval and enable disable sleep I O states can also be specified under this tab Figure 5 6 2 9 Figure 5 6 2 9 shows the second I O Setup tab contents corresponding to Bank 6 ADC input and PWM output parameters The ADC sampling interval high and low thresholds...

Page 73: ...nk 7 Figure 5 6 2 11 Figure 5 6 2 11 shows the first Routing Table tab which displays part of the contents of Bank 8 This bank contains the tree routing active router ID table which is maintained by a base for its system It describes the organization of all active routers in the system This table is used by the base and the routers to determine which direction to send a packet ...

Page 74: ...s the first seven parameters in Bank 9 This bank holds the MAC addresses of all radios registered to a base or router Up to 126 MAC addresses can be registered Each bank parameter can hold up to five MAC addresses with each MAC address containing three bytes Three byte segments in a parameter not holding a MAC address with hold a null address 0x000000 In a remote this bank will contain only null a...

Page 75: ...This allows the CCT24 to be reset F2 toggles the RTS input to the CCT24 on and off providing manual flow control F6 toggles test transmissions on and off The test message is This is a test DNT Wizard also includes the ability to log messages to and from the CCT24 This feature is especially useful in confirming the format of protocol command and reply messages Control of the log file is under the V...

Page 76: ... match the serial port connected to the Base either the hardware port or the USB virtual serial port Then click OK to activate the serial connection Figure 5 7 2 At this point the Wizard will collect data from the Base filling in data under Current Settings as shown in Figure 5 7 3 The Status Window should also show that the Remote has joined the Base Figure 5 7 3 ...

Page 77: ... DNT Wizard main window Receive Data Transmit Data and Wincom Figure 5 7 4 Received messages are displayed in the Receive Data tab along with the MAC address of the sender and the RSSI signal strength of the received message in dBm See Figure 5 7 4 ...

Page 78: ...e base is always 0x000000 If the Transmit Interval is set to 0 the message is sent once each time the Transmit button is clicked When the Transmit Interval is set to an integer greater than zero the message will sent at the beginning of each interval until the Stop button was Transmit button is clicked The status of each transmission is shown below TX Data Reply Figure 5 7 5 shows that the transmi...

Page 79: ...CT24 Figure 5 7 6 As shown in Figure 5 7 6 the Wincom tab provides the basic functionality of a serial terminal program Messages typed in are sent and messages received are appended to the bottom of the on screen text ...

Page 80: ...bove with the data on the next two tabs corresponding to configuration register Bank 6 the data on the next tab corresponding to Bank 7 the data on the following two tabs corresponding to Bank 8 and the data on the last tab corresponding to Bank 9 Figure 5 7 7 The Configuration window in the DNT Wizard is identical the Configuration window in the DNT Demo See Figures 5 6 2 2 through 5 6 2 13 for C...

Page 81: ...e 5 7 8 The Tools menu contains two very useful items Packet Builder opens the window shown in Figure 5 7 9 On the left the Packet Type drop down box provides a selection of all packet types used in the CCT24 protocol On the right the reply packet types are presented Figure 5 7 9 Figure 5 7 10 ...

Page 82: ...eply Sent Data FB 04 03 00 04 08 Get Register Recv Data FB 0C 13 00 04 08 00 05 00 01 07 00 02 00 Get Register Reply Sent Data FB 04 03 00 05 12 Get Register Recv Data FB 16 13 00 05 12 01 00 00 00 00 00 19 02 78 02 1D 02 00 00 00 00 00 00 Get Register Reply Sent Data FB 04 03 00 06 1E Get Register Recv Data FB 22 13 00 06 1E 00 00 00 01 00 00 C0 00 00 00 00 01 00 00 00 FF 03 00 00 FF 03 00 00 FF ...

Page 83: ...nfigured to assert DCD on power up In this case it will be on as long as the dev board is powered Green Activity LED D1 illuminates when transmitting or receiving RF data Red Receive LED D3 illuminates when sending received data through the serial port to the PC Green Trans mit LED D2 illuminates when the PC sends data through the serial port to be transmitted Jumper pin set J14 is provided to all...

Page 84: ...col firmware to be installed with a terminal program that supports YMODEM Pin strip J7 provides access to various CCT24 pins as shown on the silkscreen Pressing switch SW2 will reset the CCT24 Pressing switch SW1 switches GPIO0 from logic high to logic low Pin strip J8 provides access to various CCT24 pins as shown on the silkscreen The wiper of pot R10 drives the input of ADC1 Clockwise rota tion...

Page 85: ...rds at least 6 feet two meters apart 4 Start the DNT Demo program 5 Click the Connect button on the Demo window This will open a serial port setup dialog box Set the baud rate to 9600 9 6 kb s and select the COM port where the Base is connected 6 At this point the Demo will collect data from the Base filling in data in the Local Radio column on the Demo window The Status Window should also show th...

Page 86: ...Make sure the RF transmit power is not on a high settings if the nodes are close together 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 near the antenna Transmitting terminal flashes drops CTS occasionally this indicates that the transmit buffer is filling up This mo...

Page 87: ...nt is 100 µs The time stamp rolls over to 0x000 after count 0xCE5 The content of the seven data values are detailed below ASCII representations of the hexadecimal value of each byte are output separated by space characters Byte 0 current channel 0 to 36 Byte 1 same data as FSTAT 1 except no activity is 0x30 Byte 2 RSSI_Last RSSI of last RF packet received in dBm 8 bit signed value Byte 3 RSSI_Idle...

Page 88: ...el of operation is 33 decimal Byte 1 0x01 is the same status data as FSTAT data above In this case DataTx activity only Byte 2 0xDA is the last RSSI value 38 dBm Byte 3 0x98 is the RSSI idle value 100 dBm Byte 4 0x00 is the range delay estimate remote only The remote is very close to the base Byte 5 0x01 provides the serial port status HOST_CTS is high Byte 6 0x01 provides the communication status...

Page 89: ...4 8 0 Appendices 8 1 Ordering Information CCT24 transceiver module for pin socket mounting 8 2 Technical Support For CCT24 technical support call RFM at 678 684 2000 between the hours of 8 30 AM and 5 30 PM Eastern Time ...

Page 90: ... which they are not de signed or by causes external 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 oc curred Buyer has not relied and shall not rely on any oral representation regarding the goods sold here under and any oral representation shall not bind Seller and shall not be...

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