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AC4790 User`s Manual v1.4.fm

1. Ack RadioD Hop 1 R dioD RF TX 0 1 Session Count 1 Retries 1 Radios TID H H H Radioh E Radioh Session Sk RadioA Ack H Radios Rediok RE RedioB TED Radio WED RadioB Sexxion RadioB Ack RadioB Hop RedioB RF TX TED Redict Session Radiot Radio RedioC RF TK RedioD TXD RadioD FID RadioD Session Rsdiob Ack RadioD Hop Rediob RF TX 1 58 AEROCOMM Version
2. Take Pin 17 Low Software Hardware Configuration Configuration Send CC Commands Send CC Command Send Exit AT Command Mode Take Pin 17 High Command Send Another CC Command Receive Mode 6 26 CONFIGURING THE 4790 AT Commands AT COMMANDS The AT Command mode implemented in the AC4790 creates a virtual version of the Command Data pin The Enter AT Command Mode Command asserts this virtual pin Low to signify Command Mode and the Exit AT Command Mode Command asserts this virtual pin High to signify Data Once this pin has been asserted Low all On the Fly CC Commands documented in the manual are supported On the Fly Control Commands The AC4790 transceiver contains static memory that holds many of the parameters that control the transceiver operation Using the CC command set allows many of these parameters to be changed during system operation Because the memory these commands affect is static when the transceiver is reset these parameters will revert back to the settings stored in the EEPROM While in CC Command mode using pin 17 Command Data the RF interface of the transceiver is still active Therefore it can receive packets from remote transceivers while in CC Command mode and forward these to the OEM Host While in CC Command mode using AT Commands the RF interface of the transceiver is
3. 0 220 2 This GND pin to be used for RF ground 0 080 3 Operating temperature 40 to 80C H t H 0 000 3 Storage temperature 60C to 140C 0 860 EH 0 000 0 080 0220 _ 0 260 1 000 1 080 8 40 AEROCOMM Version 14 DIMENSIONS Mechanical Drawings Figure 9 AC4790 1x1 PCB Considerations Note Keep distance between 1x1 Module and antenna connector as short as possible for better performance Use several large vias 0 030 hole to tie top side ground to the bottom layer ground plane N Note Must provide solid copper Ground plane on the bottom side of pc board in this area x 1206 SMT Chip Capacitors can use 0805 0603 or even 0402 F parts Shunt parts should be symetrical about series part and close as possible AEROCOMM PN AC4790X 1X1 Terminate at RF Antenna Connector Customer s PC Boat Must continue microstrip width and grounds along the entire length PCB THickness Notes For 0 062 thick PC board microstrip width and spacing is 0 110 inches For 0 031 thick PC board microstrip width and spacing is 0 055 inches DAEROCOMM 8 41 Version 1 4 ORDERING INFORMATION PRODUCT PART NUMBER TREE 4790 Interface 485
4. 10 50 100 100 AC4790 1x1 33mA 54mA 80mA 28mA 4790 200 38mA 68mA 106mA 30mA 4790 1000 130mA 650mA 1300mA 30mA Channels Security Interface Buffer Size Frequency Band 3 Channel Sets comprising 56 total channels One byte System ID 56 bit DES encryption key Input Output 256 bytes each Transceiver 902 928 MHz RF Data Rate 76 8 kbps fixed RF Technology Frequency Hopping Spread Spectrum Output Power Conducted no antenna EIRP SdBi gain antenna 4790 1 1 10mW typical 20mW typical AC4790 200 100mW typical 200mW typical 4790 1000 743mW typical 1486mW typical Supply Voltage 4790 1 1 3 3V x50mv ripple 4790 200 3 3 5 5V x 50mvV ripple 4790 1000 Pin 10 3 3 5 5V x50mv ripple Pin 11 3 3 3 100mV ripple Pins 10 and 11 may be tied together provided the supply voltage never falls below 3 3 V and is capable of supplying 1 5 A of current Sensitivity 100dBm typical 76 8kbps RF Data Rate EEPROM write cycles 20000 Initial Transceiver Sync time Hop period 25ms 50 ms DAEROCOMM 2 5 Version 1 4 SPECIFICATIONS Pin Definitions Table 1 AC4790 Specifications antenna Temperature Operating Range Line of Site based on gain Transceiver Cont d AC4790 1x1 Up to 1 mile AC4790 200 Up to 4 miles AC4790 1000 Up to 20 miles Environmental 40 C
5. Hop MT BE RadioC RF TX RI LH RedicD TXD E Bishi AN Seat Exo i RadioD Session 1 _ RadioD Hop TENI RadioD RF TX Session Count 3 Retries 3 Radiok TED Redioh Session RedioA Ack Radiok Hop Radioj RE TX j nie ee dI z a E ume massae TTO T RedioP RF TX pesi wuc m iim nim CTT CSO Td Radiot RF TK Se 1 IA ELT OE aS RedioD TXO RadioD Session I Do RsdioD Ack E R dioD Rediob RF TX LIT D JG AEROCOMM 1 57 Version 1 4 APPENDIX IV TIMING DIAGRAMS Timing Diagrams Session Count 2 Retries 2 Radios TED H ee a Radioh Hop Radio RE TX pev rm eS ae Radio Hama NU NEM RadioB Ack H H H j H 7 RedioP TX rapa I i n s AM a Masi dd E EE PEU RETE CERIS GESTIS Radio T a RedioD e een
6. 2 Wire RS485 Blank 3 3V TTL Antenna Option A Integral Antenna 200 Only M MMCX Connector Blank AC4790 1x1 No Antenna Output Power 200 200 mW US Canada Only 1000 1000 mW 3 3V MMCX Only 1x1 Multichip Module 10 mW DEVELOPER KIT PART NUMBERS All of the above part numbers can be ordered as a development kit by prefacing the part number with SDK As an example part number AC4790 200A can be ordered as a development kit using the part number SDK AC4790 200A All developer s kits include 2 transceivers 2 development boards 2 7 5 VDC unregulated power supplies 2 serial cables 2 USB cables 2 antennas configuration testing software and integration engineering support 9 42 COMPLIANCY INFORMATION AC4790 1X1 Due to the RF antenna trace residing on the OEM Host PCB the FCC will not grant modular approval for the AC4790 1x1 and requires the OEM to submit their completed design for approval Contact AeroComm for the approval procedure AGENCY IDENTIFICATION NUMBERS Agency compliancy is a very important requirement for any product development AeroComm has obtained modular approval for its products so the OEM only has to meet a few requirements to be eligible to use that approval The corresponding agency identification numbers and approved antennas are listed below Table 13 Agency Identification Numbers Part Number US FCC 4790 200 KQLAC4490 100 2
7. 49 OxOE 82 0x84 52 0x11 86 Ox9A 56 0x17 89 OxAD 59 Ox1C 92 OxBD 6 31 AEROCOMM Version 14 Read ADC The OEM Host issues this command to read any of the three onboard 10 bit A D converters Because the RF is still active in On the Fly Command Mode the transceiver will not process the command until there is no activity on the network The Read RSSI command is therefore useful for detecting interfering sources but will not report the RSSI from a remote transceiver on the network The equations for converting these 10 bits into analog values are as follows Analog Voltage 10 bits Ox3FF 3 3V Temperature 9C Analog Voltage 0 3 0 01 30 RSSI value dBm 105 0 22 Ox3FF 10 bits Write Digital Outputs The OEM Host issues this command to write both digital output lines to particular states Note This command should only be used when Protocol Status 0xC2 is not set to OxE3 Probe Enabling bit 6 of API Control will enable this command When the OEM Host issues this command the transceiver sends out a query every 500 ms The transceivers upon receiving the query randomly choose a query to respond to After responding to a Probe the transceiver will wait at least 10 seconds before responding to another probe Apart from the transceiver response there are two other responses that provide crucial information to the OEM Host This information can be used to
8. 8 10 RTS 9 19 GO1 10 2 PWR VCC1 11 11 PWR VCC2 12 23 13 12 RSSI 14 212 Gi 15 16 _ 16 13 GND GND 17 17 CMD Data Non inverted RS 485 representation of serial data Data input to the transceiver Mirror image of RS 485 A Generic Input pin Signal Ground Has internal connection for AeroComm use only Clear to Send Active Low when the transceiver is ready to accept data for transmission Request to Send When enabled in EEPROM the OEM Host can take this High when it is not ready to accept data from the transceiver NOTE Keeping RTS High for too long can cause data loss Received Acknowledge status pin if Protocol Status is enabled Otherwise generic output 4790 1 1 3 3V 50mV ripple 4790 200 3 3 5 5V 50 ripple Pin 10 is internally connected to Pin 11 AC4790 1000 3 3 5 5V 50mV ripple 4790 1 1 3 3V x50mvV ripple 4790 200 3 3 5 5V x50mV ripple Pin 11 connected to Pin 10 4790 1000 3 3V 3 100mV ripple is internally Test Mode When pulled logic Low and then applying power or resetting the transceiver s serial interface is forced to a 9600 8 N 1 rate To exit the transceiver must be reset or power cycled with Test Mode logic High Received Signal Strength An analog output giving an instantaneous indication of received signal strength Only valid while in Receive Mode Generic Input pin RESET Controlled
9. CTS On specifies the amount of bytes that must be in the buffer for CTS to be disabled logic High Even while CTS is disabled the OEM Host can still send data to the transceiver but it should do so carefully Note The CTS On Off bytes of the EEPROM can be set to 1 in which case CTS will go high as data is sent in and low when buffer is empty 5 23 HARDWARE INTERFACE Pin Definitions RTS With RTS disabled the transceiver will send any received data to the OEM Host as soon as it is received However some OEM Hosts are not able to accept data from the transceiver all of the time With RTS enabled the OEM Host can prevent the transceiver from sending it data by disabling RTS logic High Once RTS is enabled logic Low the transceiver can send packets to the OEM Host as they are received Note Leaving RTS disabled for too long can cause data loss once the transceiver s 256 byte receive buffer fills up Test 9600 Baud When pulled logic Low before applying power or resetting the transceiver s serial interface is forced to a 9600 8 N 1 8 data bits No parity 1 stop bit To exit the transceiver must be reset or power cycled with Test pin logic High This pin is used to recover transceivers from unknown baud rates only It should not be used in normal operation Instead the transceiver Interface Baud Rate should be programmed to 9600 baud if that rate is desired for normal operation The Test 9600 pin should be used for recov
10. Software selectable interface baud rates from 1200 bps to 115 2 kbps Low cost low power and small size ideal for high volume portable and battery powered applications All modules are qualified for Industrial temperatures 40 C to 80 C Advanced configuration available using AT commands OVERVIEW The 4790 is a member of AeroComm s OEM transceiver family The 4790 is a cost effective high performance frequency hopping spread spectrum transceiver designed for integration into OEM systems operating under FCC part 15 247 regulations for the 900 MHz ISM band 4790 transceivers operate in a Masterless architecture The unique feature of this architecture is its dynamic Session extension and Collision Avoidance mechanism which uses a proprietary scoring system to promote contention free communication and ensure that each node has fair access to the network This instinctive dynamic peer to peer networking architecture enables Several transceiver pairs to carry on simultaneous conversations on the same network 1 3 AC4790 TRANSCEIVER MODULE Overview To boost data integrity and security the AC4790 uses AeroComm s field proven FHSS technology featuring optional Data Encryption Standards DES Fully transparent these transceivers operate seamlessly in serial cable replacement applications Communications include both system and configuration data via an asynchronous TTL or optional RS 485 serial interface
11. Broadcast Attempts how often you send data non delivery network timeouts and interface data rate Polled type networks where the Server host requests data from the Client host and the Client host responds are good candidates for avoiding the use of CTS This is because no one transceiver can monopolize the RF link Asynchronous type networks where any radio can send to another radio at any point in time are much more difficult to implement without the use of CTS HALF DUPLEX FULL DUPLEX When Half Duplex communication is chosen the AC4790 will send a packet out over the RF whenever it can This can cause packets sent by multiple transceivers at the same time to collide with each other over the RF To prevent this Full Duplex communication can be chosen Full Duplex shares the bandwidth intelligently to enable two way collision free communication without any collision This is done by calculating the amount of time until the next hop to ensure that it has time to send the packet if there is enough time it will send the packet and if not it will wait until its next appropriate hop The radio which initiates the session transmits during the even hops while the remaining radio s will transmit during the odd hops Although the RF hardware is still technically half duplex the bandwidth sharing it makes the transceiver seem full duplex Enabling Full Duplex can cause overall throughputs to be cut in half 4 19 AEROCOMM Version 14 SERIA
12. Data Length 4 This continues until all radios have successfully been polled by the SAP Broadcast Transmit API To send out a universal poll request or data packet the OEM may wish to utilize the broadcast portion of the Transmit command The Broadcast command is similar to the addressed command only with the Destination MAC Address set to all OxFF DAEROCCOMM ves APPENDIX III API Polling Network 81 06 08 04 FF FF FF 73 74 61 74 75 73 Payload Data STATUS Broadcast Packet Number of Transmit Retries Session Count Refresh Payload Data Length The remote response is dependent on the OEM s specific needs and equipment In many cases remote radios are connected to dumb devices without the intelligence to filter out or append specific portions of a packet that is transmitted or received Since the 7 bytes of overhead in the Transmit command are not sent over the RF the remotes will receive only the payload data STATUS If auto destination is enabled on the remote radio the transceiver will automatically change its destination address to that of the radio it last received a packet from When the remote device sends its response it will therefore automatically be routed back to the SAP Depending on the API configuration of the SAP the packet will be received in one of two formats Receive API When Receive API is enabled the transceiver will receive the reply data the MAC address of the source radio an
13. Session and begin receiving data While in Receive Mode subsequent data of up to 128 bytes can be received every hop 50 ms When a transceiver is in Session its Session Count is decremented by one every hop When the Session Count reaches zero the transceiver exits the Session In order to continue receiving data the transceivers update their Session Count every time data or an RF acknowledge is received SLockO SLock1 settings control Session Count as shown below Table 5 Session Count Truth Table Slock1 Transceiver Receiving an Transceiver Receiving a Addressed Packet Broadcast Packet 1 0 0 Radio loads its Current Session Radio loads its Current Session Count Count with its Session Count with its Session Count Refresh Refresh 2 0 1 Radio loads its Current Session Radio loads its Current Session Count Count with its Transmit Retries with its Broadcast Attempts its its Session Count Refresh Session Count Refresh 3 1 0 Radio loads its Current Session Radio loads its Current Session Count Count with the remote radio s with the remote radio s Session Count Session Count 4 1 1 Radio loads its Current Session Radio loads its Current Session Count Count with the remote radio s with the remote radio s Current Session Current Session Count Count EEPROM Default Note 1 For Broadcast Addressed packets the Session Count for Full Duplex is 2x the value of Session Count in Half Du
14. for OEM Host communications Configuration data is stored in an on board EEPROM and most parameters can be changed on the fly All frequency hopping synchronization and RF system data transmission reception is performed by the transceiver This document contains information about the hardware and software interface between an AeroComm AC4790 transceiver and an OEM Host Information includes the theory of operation specifications interface definition configuration information and mechanical drawings The OEM is responsible for ensuring the final product meets all appropriate regulatory agency requirements listed herein before selling any product Note Unless mentioned specifically by name the AC4790 modules will be referred to as the radio or transceiver Individual naming is used to differentiate product specific features The host PC Microcontroller Any device to which the AC4790 module is connected will be referred to as OEM Host 1 4 AEROCOMM Version 14 SPECIFICATIONS Table 1 AC4790 Specifications General 20 Pin Interface Connector Molex 87759 0030 mates with Samtec SMM 110 02 S D RF Connector Johnson Components 135 3711 822 Antenna AC4790 1x1 Customer must provide AC4790 200 MMCX Connector or integral antenna AC4790 1000 MMCX Connector Serial Interface Data Rate Baud rates from 1200 bps to 115 200 bps Power Consumption typical Duty Cycle TX Transmit RX Receive
15. monitor the network and determine alternate routing paths Probe Report Remote transceiver s response to its OEM host upon receiving a Probe query Note Only valid when Probe Report address OxC9 is set to OxE3 Transceiver s Response Upon hearing the remote transceivers probe acknowledge the transceiver sends a response to the OEM Host DAEROCOMM CONFIGURING THE AC4790 Command Descriptions Command OxCC 0x21 Data1 Number of Bytes Returned 3 Response OxCC Data2 Data3 Parameter Range Data1 0x00 AD In 0x01 Temperature 0x02 RSSI Data2 MSB of requested 10 bit ADC value Data3 LSB of requested 10 bit ADC value Command OxCC 0x23 Data1 Number of Bytes Returned 2 Response OxCC Data1 Parameter Range Data1 bit 0 GOO bit 1 GO1 Command OxCC Ox8E Data1 Number of Bytes Returned 2 Response OxCC 1 Parameter Range 0x00 Disable Probe Ox01 Enable Probe Command N A Number of Bytes Returned 5 Response 0x86 RSSI MAC2 MAC1 Parameter Range MAC2 MAC1 3 LSB s of radio sending the Probe query Command N A Number of Bytes Returned 6 Response 0x87 RSSI RSSI 2 MAC1 Parameter Range RSSI How strong remote heard local transceiver RSSI How strong local heard remote transceiver 6 32 Version 1 4 EEPROM Byte Read Upon receiving this command a transceiver will
16. respond with the desired data from the addresses requested by the OEM Host EEPROM Byte Write Upon receiving this command a transceiver will write the data byte to the specified address but will not echo it back to the OEM Host until the EEPROM write cycle is complete up to 10 ms Multiple byte writes of up to 128 bytes are allowed An EEPROM boundary exists between addresses Ox7F and 0x80 No single EEPROM write command shall write to addresses on both sides of that EEPROM boundary Reset The OEM Host issues this command to perform a soft reset of the transceiver Any transceiver settings modified by CC commands will revert to the values stored in the EEPROM DAEROCOMM CONFIGURING THE AC4790 Command Descriptions Command OxCC 0 0 Data1 Data2 Number of Bytes Returned 4 Response 0 Data1 Data2 Data3 Parameter Range Data1 EEPROM address Data2 Length 0x00 0x80 Data3 Requested data Command OxCC OxC1 Data1 Data2 Number of Bytes Returned 4 Response Data1 Data2 Data Parameter Range Data1 EEPROM address Data2 Length 0x00 0x80 Data3 Data written Command OxCC OxFF Number of Bytes Returned None Response None 6 33 Version 1 4 EEPROM PARAMETERS The OEM Host can program various parameters that are stored in EEPROM which become active after a power on reset The table below gives the locations and descriptions o
17. 0 Number of Bytes Returned 3 Response OxCC Version XX Parameter Range XX 0x00 0x03 Ignore Command OxCC 0x01 Channel Number of Bytes Returned 2 Response OxCC Channel Command OxCC 0x08 Data1 Number of Bytes Returned 2 Response OxCC Data1 Parameter Range Data1 0 00 for Addressed 0x01 for Broadcast Command OxCC 0x10 MAC3 2 MAC1 Number of Bytes Returned 4 Response 0xCC MAC2 MAC1 Parameter Range 0x00 OxFF corresponding to LSB s of destination MAC Address 6 29 Version 1 4 Read Destination Address The OEM Host issues this command to the transceiver to read the destination address Note Only the three Least Significant Bytes of the MAC Address are used for packet delivery Auto Destination The Host issues this command to change the Auto Destination setting When issuing this command the Auto Destination setting will only be changed if the corresponding enable bit is set Controli Parameter EEPROM address 0x56 bit 4 Read API Control The OEM Host issues this command to read the API Control byte Write API Control The OEM Host issues this command to write the API Control byte Set Max Power The OEM Host issues this command to limit the maximum transmit power emitted by the transceiver This can be useful to minimize current consumption and satisfy certain regulatory requirements The radios are shipp
18. 1 3 3 0 0 99 2 5 5 0 0 8 V GIO 2 31 3 3 0 0 99 2 5 5 0 0 8 V RTS 2 31 3 3 0 0 99 2 5 5 0 0 8 V Test 2 31 3 3 0 0 99 2 5 5 0 0 8 V GH 2 31 3 3 0 0 99 2 5 5 0 0 8 V UP RESET 0 8 3 3 0 0 6 0 8 5 0 0 6 V Command Data 2 31 3 3 0 0 99 2 55 0 0 8 V AD In N A 3 3 0 N A N A 3 3 0 N A V Table 4 Output Voltage Characteristics Signal Name i GOO 1 19 2 5 8mA 0 4 8mA V TXD 2 6 2 5 2mA 0 4 2 V RS485A B 2 3 N A 1 0 3 3 1 8 Unit Load N A CTS 7 9 2 5 2 0 4 2 V GO1 9 19 2 5 2mA 0 4 2 V RSSI 13 12 See Figure 1 See Figure 1 V Session Status 20 18 2 5 9 2mA 0 4 2 V GOO 1 19 2 5 8mA 0 4 8mA V 3 2 9 THEORY OF OPERATION MASTERLESS ARCHITECTURE The Masterless architecture is a true peer to peer architecture where any module that has data to transmit will initiate a communication Session with a transceiver s within its range transmit data and exit the Session This architecture eliminates the need for a master which dictates data flow control hence reducing additional system overhead and greatly improving efficiency MODES OF OPERATION The AC4790 has three different operating modes Receive Transmit amp Command Mode If the transceiver is not communicating with another radio it will be in Receive Mode actively listening for a sync pulse from another transceiver If the radio determines t
19. 268C AC4490 AC4790 1000 KQL AC4490 1000 2268C AC44901000 APPROVED ANTENNA LIST The following antennas are approved for use with the AC4790 as identified The OEM is free to choose another vendor s antenna of like type and equal or lesser gain as a listed antenna and still maintain compliance Table 14 AC4790 Approved Antennas Aer mm goso Manufacturer Part Part Manufacturer Number Number 0600 00019 S467 FL 5 RMM 915S Nearson 1 2 Wave Dipole 2 X X 0600 00025 S467 FL 5 RMM 915 Nearson 1 2 Wave Dipole 2 X X 0600 00024 467 915 1 2 Wave Dipole 2 X X 0600 00027 5467 915 Nearson 1 2 Wave Dipole 2 X X 0600 00028 5161 915 Nearson 1 2 Wave Dipole 2 5 X X 10 43 COMPLIANCY INFORMATION Requirements for Modular Approval Table 14 AC4790 Approved Antennas AeroComm Manufacturer Part Part Manufacturer Type Number Number 0600 00029 161 915 Nearson 1 2 Wave Dipole 2 5 X X 0600 00030 S331 AH 915 Nearson 1 4 Wave Dipole 1 X X 1020B5812 04 Flavus gigaAnt Microstrip 0 5 X IC REQUIREMENTS FOR MODULAR APPROVAL In general there are two agency classifications of wireless applications portable and mobile Portable Portable is a classification of equipment where the user in general will be within 20 cm of the transmitting antenna Portable equipment is further broken down
20. 6 packet times then retry Ox1F Wait 1 32 packet times then retry Ox3F Wait 1 64 packet times then retry Ox7F Wait 1 128 packet times then retry OxFF Wait 1 256 packet times then retry Sesnse Adjust OxC8 1 Ox00 Set in The minimum RSSI required by a transceiver to OxFF Production establish a session upon hearing a long beacon and can vary Probe Report 0 9 1 0x00 OxES When set to OxE3 upon receiving a probe the OxFF transceiver sends a Probe Report to the OEM Host DES Key OxDO 7 0x00 56 bit Data Encryption key OxFF 1537 AEROCOMM Version 14 MMENSIONS MECHANICAL DRAWINGS Interface Connector 20 pin OEM Interface connector Molex 87759 0030 mates with Samtec SMM 110 02 S D Jack Antenna Connector Johnson Components 135 3711 822 AC4790 with MMCX connector Mechanical Figure 6 AC4790 with MMCX connector Mechanical 20 pin header 0 020 sq posts on 0 079 inch 2mm centers 0 157 0 180 EE AN 0 062 0 067 0 000 E jack 0 125 dia non plated holes 0 100 dia non plated hole 2 places 1 place under shield 1 650 1 650 O 1 550 o 1 320 pins 12 10 O 1 010 O 5 0 825 21 O gt O O O O jack 0 145 dia O O O 0200529009 O O O 0 000 0 000 e x DAERO
21. 7 14 18 2 i 1Y2 lt Yo Input A 8 13 16 4 143 2M1 Y ATI InputB 9 12 14 6 2 0 lt 2 A21 InputC 10 11 12 8 Gnd 2A0 e va Input D 74LVC244 74LVC244 Passive Resistor Voltage Divider While a resistor voltage divider can successfully drop the 5V to the required 3 3V it will draw static current all of the time Typically this method is only suitable for one way 5V to 3 3V conversion When choosing the resistor values one needs to include the radio s internal 10 kohm resistors on the input signals 1 49 APPENDIX III The API feature set of the AC4790 provides powerful packet routing capabilities to the OEM Host The number of API configurations is endless as individual radios can all be configured differently to suit the OEM Host s varying needs Some of the most common implementations are described in the following pages POLLING NETWORK Many applications require multiple locations to report back to a single access point One solution would be to enter Command mode change the transceiver s destination address and then exit Command mode to resume normal operation When it is time to communicate with another transceiver the process would be repeated costing time and inevitably reduction in throughput as unnecessary commands are issued As an alternative the Transmit API command can be used to control packet routing on a packet by packet bas
22. 8 Diode MELF LL4148 Switch Diodes Inc LL4148 Diode L1 15uH Xfmr 2P SMT 15uH 2A Coiltronics UP2 8B150 U1 CS51413 IC CS51413 8P SO Switch Reg On Semi CS51413 Ctrl cond 1 46 Version 1 4 APPENDIX I SAMPLE POWER SUPPLY Schematic SCHEMATIC Switching Power Supply 3 4V V_OUT 15A C6 3300pF 65 V INPUT 46V to 18V C2 TUF 35 35 2 1 47 DAEROCOMM vial APPENDIX I SAMPLE POWER SUPPLY PCB Layout PCB LAYOUT VIN GND VOUT 1 48 DAEROCOMM ves APPENDIX 5V TO 3 3V LEVELS All inputs on the AC4790 200 amp 4790 1000 are weakly pulled high via 10 kohm resistors 4790 200 has 5V inputs while the AC4790 1000 amp AC4790 1x1 have 3 3V inputs 4790 200 uses an octal buffer to drop the 5V to the required 3 3V level the 1000 and 1x1 leave this to the OEM Some of the most common voltage conversion methods are described below Voltage Level Conversion IC s This is the easiest and most efficient method Aerocomm recommends the SN74LVC244A Octal Buffer Driver Inputs can be driven from either 3 3 or 5V systems allowing the device to be used in a mixed 3 3 5V system 1 20 10E vec 2 19 140 208 3 18 2v3 1Yo 4 17 1 1 2 3 5 16 2v2 6 15 L 142 2 2 1
23. COMM 8 38 Version 1 4 DIMENSIONS Mechanical Drawings Figure 7 AC4790 with integral gigaAnt Antenna on bottom Mechanical 0 157 0 062 0 000 1 650 1 550 1 010 0 100 0 000 20 pin header 0 020 sq posts on 0 079 inch 2mm centers 0 180 0 086 0 000 10152 GigaAnt Snap In Antenna 0 125 dia non plated holes 4 places 1 650 E e 1 180 _ 98559256 0 000 8 39 AEROCOMM Version 1 4 DIMENSIONS Mechanical Drawings Figure 8 AC4790 1x1 Mechanical Module Outline 8 5 21 20 19 18 17 16 15 0 131 RESET 14 RF PORT y gt 0 031 9600_BAUD TST_MODE 13 GND note 2 0 000 N C 12 RSSI N C 11 VCC note 1 N C 10 RTS N C L2 9 CTS cut corner x 3 indicates 1 i 1 000 1 2 3 4 5 e 8 E AEROCOMM RECOMMENDED PAD PATTERN AC4790 1X1 viewed from top TA gt 1 080 005068004503 0 080 x 0 040 pad N H H H H 1 000 ooo 0 000 typical 0 860 m Eu J typ 8 58 8 LE LE x DEN 7 LE LE Notes 1 VCC must not exceed 3 3V DC LE 0 10 typ
24. E8 0x00 0x05 0x39 4800 OxDO 0x00 0x09 Ox7A 2400 OxAO 0x00 0 11 OxFC 1200 0x40 0x00 0 21 0x00 1 57 600 is the default baud rate 2 0x00 will yield a stop bit of 421 uS The stop bit at 1200 baud should actually be 833 uS INTERFACE TIMEOUT RF PACKET SIZE Interface Timeout EEPROM address 0x58 in conjunction with RF Packet Size EEPROM address 0x5B determines when a buffer of data will be sent out over the RF as a complete RF packet based on whichever condition occurs first Interface Timeout Interface Timeout specifies a maximum byte gap between consecutive bytes When that byte gap is exceeded the bytes in the transmit buffer are sent out over the RF as a complete packet Interface Timeout is adjustable in 0 5ms increments and has a tolerance of 0 5ms Therefore the Interface Timeout should be set to a minimum of 2 The default value for Interface Timeout is 0x04 2ms and should be adjusted accordingly when changing the transceiver baud rate RF Packet Size When the number of bytes in the transceiver transmit buffer equals RF Packet Size those bytes are sent out as a complete RF packet It is much more efficient to send a few large packets rather than several short packets as every packet the transceiver sends over the RF contains extra header bytes which are not included in the RF Packet Size RF packet size can 4 18 AEROCOMM Version 14 SERIAL INTERFACE Flow Control be set to a maximum of 0x80 and must be s
25. ENDIX III API Time Division Multiple Access Network MAC 12 34 56 MAC 12 34 A1 MAC 12 34 A2 12 34 Loopback Repeater If radios B amp C in the above picture are not within range of radio A they will not be able to receive or respond to communications from radio A A loopback repeater can be added between the three such that it is in range of both radio A and radios B amp C When the repeater receives a packet from radio A it will transmit the packet out to radios B amp C If the repeater is set to Broadcast mode radio A will receive a copy of each packet that it sends If the repeater has a specific destination address i e 12 34 A2 then radio A will not receive the packet as its MAC address will not match the specified destination address TIME DIVISION MULTIPLE ACCESS NETWORK For a more intelligent network a TDMA system can be implemented In this system various radios transmit data to a Shared Access Point SAP during an assigned time interval The system is synchronous so that only one radio is transmitting at a time and has full access to the SAP s bandwidth In a TDMA network each radio must store its data for the amount of time between its transmissions or bursts A typical format for data passing through a SAP is shown below A frame consists of arriving bursts from remote radios and each frame is then divided into multiple time slots The bursts can be of varying lengths and can be longer for heavy traff
26. Figure 4 RSSI Voltage vs Received Signal Strength 1 2 0 8 0 6 Voltage VDC 0 4 0 2 105 100 95 90 85 80 75 70 65 60 55 50 Signal at Receiver dBm UP_Reset UP_Reset provides a direct connection to the reset pin on the AC4790 microprocessor and is used to force a soft reset For a valid reset reset must be asserted High for a minimum of 10ms Command Data When logic High the transceiver interprets incoming OEM Host data as transmit data to be sent to other transceivers and their OEM Hosts When logic Low the transceiver interprets OEM Host data as command data AD In AD In can be used as a Cost savings to replace Analog to Digital converter hardware Reading of this pin can be performed locally using the Read ADC command found in the On the Fly Control Command Reference Session Status Reports logic Low during a Session and logic High when not in Session The inverse of this pin can be obtained from pin GOO when Protocol Status is enabled 5 25 DAEROCOMM vein CONFIGURING THE AC4790 The AC4790 can be configured using the CC Configuration Commands The CC Commands can be issued using either Hardware or Software Configuration To use Hardware Configuration pin 17 of a transceiver must be asserted Low Software Configuration can be used by entering AT Command Mode before issuing the CC Commands Figure 5 AC4790 Configuration Flow Receive Mode Use AT Commands
27. L INTERFACE System Timing amp Latency SYSTEM TIMING amp LATENCY Care should be taken when selecting transceiver architecture as it can have serious effects on data rates latency and overall system throughput The importance of these three characteristics will vary from system to system and should be a strong consideration when designing the system ENGINEER S TIP In High density applications what amount of latency should be expected It is not easy to predict the exact amount of latency in high density applications There are many variables that affect system latency The three variables that most affect the latency are the network load the distance between transceivers and whether the transceivers are operating in a broadcast or addressed mode There is no fixed answer as to how much latency will be introduced in the system when considering high density applications In these cases we can just offer qualitative analysis of the latency in high density applications As the network load increases then the number of collisions that will occur increases As the number of collisions increase then the system latency increases As the distance between the transceivers increases so to does the system latency Finally when transceivers operate in addressed mode they will retry sending a packet up to the number of time specified in the transmit retry parameter specified in the EEPROM As the number of retries increases the system latency
28. Mode Signal START bit STOP bit e e e e e The UART outputs and inputs logic level signals on the TX and RX pins The signal is high when no data is being transmitted and goes low when transmission begins The signal stays low for the duration of the START bit and is followed by the data bits LSB first The STOP bit follows the last data bit and is always high After the STOP bit has completed the START bit of the next transmission can occur Parity A parity bit is used to provide error checking for a single bit error When a single bit is used parity can be either even or odd Even parity means that the number of ones in the data and parity sum to an even number and vice versa The ninth data bit can be used as a parity bit if the data format requires eight data bits and a parity bit as shown below Figure 3 Even Parity Bit 4 16 SERIAL INTERFACE OEM Host Data Rate 5 5 8 zB E N Qo CQ 1 0 1 7 0 0 4 O 0 1 Note Enabling parity cuts throughput and the interface buffer in half OEM HOST DATA RATE The OEM Host Data Rate is the rate with which the OEM Host and transceiver communicate over the serial interface This rate is independent of the RF baud rate which is fixed at 76 8 kbps Possible values range from 1200 bps to 115 200 bps Note Enabling Parity cuts throughput in half and the Interface Buffer size in half The following asy
29. OTOCOL STATUS When the GOO pin is configured as the Session Status pin GOO is normally Low GOO will go High when a Session is initiated and remain High until the end of the Session When the GO1 pin is configured as the Receive Acknowledge Status GO1 is normally Low and GO1 will go High upon receiving a valid RF Acknowledgement and will remain High until the end rising edge of the next hop TXD amp RXD SERIAL TTL The AC4790 200 accepts 3 3 or 5VDC TTL level asynchronous serial data on the RXD pin and interprets that data as either Command Data or Transmit Data Data is sent from the transceiver at 3 3V levels to the OEM Host via the TXD pin Note The 4790 1000 amp 4790 1 1 transceivers ONLY accept 3 3V level signals RS 485 When equipped with an onboard RS 485 interface chip TXD and RXD become the half duplex 5 485 pins The transceiver interface will be in Receive Mode except when it has data to send to the OEM Host TXD is the non inverted representation of the data RS485A and RXD is a mirror image of TXD RS485B The transceiver will still use RTS if enabled CTS The 4790 has an interface buffer size of 256 bytes If the buffer fills up and more bytes are sent to the transceiver before the buffer can be emptied data loss will occur The transceiver prevents this loss by asserting CTS High as the buffer fills up and taking CTS Low as the buffer is emptied CTS On and CTS Off control the operation of CTS
30. PI Receive Packet is enabled when bit 0 of the API Control byte is enabled Upon receiving a packet the radio sends its OEM Host the packet in the following format Payload Data 0x81 Length RSSI RSSI Source MAC Payload 0x01 0x80 2 1 0 Data ENGINEER S When both API Send Data Complete and API Receive Packet are enabled the Send Data Complete will be received before the transceiver sees the Receive API Packet This order may get reversed when the API Send Data Complete is missed and is being resent after the API Receive Packet is received 3 15 DAEROCOMM SERIAL INTERFACE In order for the OEM Host and a transceiver to communicate over the serial interface they need to have the same serial data rate Refer to the following sections to ensure that the OEM Host data rate matches the serial interface baud rate SERIAL COMMUNICATIONS The AC4790 is a TTL device which can be interfaced to a compatible UART microcontroller or level translator to allow connection to serial devices UART stands for Universal Asynchronous Receiver Transmitter and its main function is to transmit or receive serial data Asynchronous Operation Since there is no seperate clock in asynchronous operation the receiver needs a method of synchronizing with the transmitter This is achieved by having a fixed baud rate and by using START and STOP bits A typical asynchronous mode signal is shown below Figure 2 Asynchronous
31. RESSES OUR COMM ME T 57 oo Version 1 4 YAEROCCOMM DOCUMENT INFORMATION Copyright 2006 AeroComm Inc All rights reserved The information contained in this manual and the accompanying software programs are copyrighted and all rights are reserved by AeroComm Inc AeroComm Inc reserves the right to make periodic modifications of this product without obligation to notify any person or entity of such revision Copying duplicating selling or otherwise distributing any part of this product or accompanying documentation software without the prior consent of an authorized representative of AeroComm Inc is strictly prohibited All brands and product names in this publication are registered trademarks or trademarks of their respective holders This material is preliminary Information furnished by AeroComm in this specification is believed to be accurate Devices sold by AeroComm are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only AeroComm makes no warranty express statutory and implied or by description regarding the information set forth herein AeroComm reserves the right to change specifications at any time and without notice AeroComm s products are intended for use in normal commercial and industrial applications Applications requiring unusual environmental requirements such as military medical life support or life sustaining
32. acters CTS Off Ox5D 1 Ox00 OxAC Once CTS has been deasserted CTS will be OxFE reasserted Low when the transmit buffer is contains this many or less characters Max Power 0x63 1 0 00 Set in Used to increase decrease the output power The 0x60 Production transceivers are shipped at maximum allowable amp can vary power Parity Ox6F 1 OxES OxFF 0 Enable Parity OxFF OxFF Disable Parity Note Enabling parity cuts throughput and the interface buffer size in half Destination ID 0x70 6 Ox00 Specifies destination for RF packets OxFF System ID 0x76 1 Ox00 0x01 Similar to network password Radios must have the OxFF same system ID to communicate with each other RS 485 DE Ox7F 1 OxE3 OxFF 0 GOO is active Low DE for control of external OxFF RS 485 hardware OxFF Disable RS 485 DE MAC ID 0x80 6 Ox00 Factory programmed unique IEEE MAC address OxFF DAEROCOMM 7 35 Version 1 4 EEPROM PARAMETERS Command Descriptions Table 12 EEPROM Parameters EEPROM Address Length Bytes Default Parameter Ox8E 1 Set in Production and can vary Original Max Power Description Copy of original max power EEPROM setting This address may be referenced but should not be modified Product ID 0x90 15 0x90 0x93 Product ID 0x94 0x95 Prefix CL CN or AC 0x96 0x99 Power 200M 200A 1000 1x1 Note There will be a period in front of the 1x1 to keep the field at f
33. active but packets sent from other transceivers will not be received The transceiver uses Interface Timeout RF Packet Size to determine when a CC Command is complete Therefore there should be no delay between each character as it is sent from the OEM Host to the transceiver or the transceiver will not recognize the command If the OEM Host has sent a CC Command to the transceiver and an RF packet is received by the transceiver the transceiver will send the CC Command response to the OEM Host before sending the packet However if an RF packet is received before the Interface Timeout expires on a CC Command the transceiver will send the packet to the OEM Host before sending the CC Command response When an invalid command is sent the radio scans the command to see if it has a valid command followed by bytes not associated with the command in which case the radio discards the invalid bytes and accepts the command In all other cases the radio returns the first byte of the invalid command back to the user and discards the rest 6 27 AEROCOMM Version 1 4 CONFIGURING THE 4790 AT Commands Table 10 Command Quick Reference Command Name Command All Bytes in Hex Return All Bytes in Hex AT Enter 0x41 0x54 0x2B 0x2B 0x2B OxOD OxCC 0x43 0x4F 0x4D CommandMode Exit AT Command OxCC Ox41 0x54 0x4F 0x0D OxCC 0 44 0 41 0 54 Mode Status Request OxCC 0x00 0x00 OxCC Firmware Ver 0x00 sion 0x03 Change Channel OxCC 0x01 New Cha
34. ad Data FIND 0 Destination MAC Address Number of Transmit Retries Session Count Refresh Payload Data Length 1 53 DAEROCOMM vein APPENDIX III API Loopback Repeater 2 Radio receives the packet FIND D and stores it in the buffer until the current session with Radio A has ended Once the current session ends Radio B forwards the packet from its buffer to Radio C 81 06 08 04 12 34 A2 66 69 6E 64 20 64 Payload Data FIND 0 Destination MAC Address Number of Transmit Retries Session Count Refresh Payload Data Length 3 Radio C receives the packet FIND D and stores it in the buffer until the current session with Radio B has ended Once the current session ends Radio C forwards the packet from its buffer to Radio D 81 06 08 04 12 34 A3 66 69 6E 64 20 64 Payload Data FIND 0 Destination MAC Address Number of Transmit Retries Session Count Refresh Payload Data Length 4 Radio D receives the packet FIND D and sends the appropriate response back down the line to Radio A LOOPBACK REPEATER The simplest repeater to implement is a loopback repeater A loopback repeater can be created by connecting the transceiver s RXD and TXD lines together When the radio receives data it will retransmit the data to all available transceivers on the network It is important not to have two loopback repeaters in range of each other as they will continuously transmit data back and forth 1 54 AEROCOMM Version 1 4 APP
35. ansceiver on the network To increase the odds of successful delivery Broadcast attempts are utilized Transparent to the OEM Host the sending radio will send the RF packet to the intended receiver s Unlike transmit retries all broadcast attempts are used regardless of when the RF packet is actually received and without RF acknowledgements If the packet is received on the first attempt the receiver will ignore the remaining broadcast attempts The received packet will only be sent to the OEM Host if and when it is received free of errors 3 10 THEORY OF OPERATION Modes of Operation When a radio has data to transmit it sends out a sync pulse to initiate a session with one or more radios This 25 ms sync pulse is sent during the first half of each 50 ms hop and transparent to the OEM Host Once a Session has been established the radio transmits the data during the remaining 25 ms of the current hop The radio will stay in Transmit mode until its Session Count expires When sending addressed packets Session Count is defined as Session Count Refresh EEPROM address 0 4 number of transmit retries EEPROM address 0x4C When sending broadcast packets Session Count is equal to Session Count Refresh EEPROM address 0 4 number of broadcast attempts EEPROM address Ox4D Once the radio exits the Session it returns to the default Receive Mode Receive Mode If a transceiver detects a sync pulse while in Receive Mode it will join the
36. ard Packet Mode BN Pa E b P N Fi S d 72 DEEST IEEE 22 22 y LIN pA S d NS pd SS _ Receive lt packet and Addressed Packet E AT gt check CRC 2 Y Yes X N gt p lt N Yes 2 Duplicate Matching s pa lt Packet lt Destination 5 4 RF Data gt M 4 S MAC 4 hw v di 5 F N ae 9 V Y Y Yes YO N Send Packetovar lt Validate CRC gt Broadcast Packet gt Addressed Packet E A ES X Yes 1 oN yt y lt Duplicate Yes Transmit Packet Transmit Packet ee N Send Packet over Send RF Decrement Broadcast lt Receive ACK gt Attempts PS x H Pt gi N Broadcast NS Decrement V Attempts 0 42 Transmit Attempts EN Mw Transmit N lt att mpts Atte 5 gt ES y e API CONTROL API Control is a powerful feature that the Masterless Protocol offers When enabled the API Transmit Packet API Send Data Complete and API Receive Packet features provide dynamic packet routing and packet accounting ability to the OEM Host thereby eliminating the need for extensive programming on the OEM Host side This ability of the protocol makes it ideal for any legacy system operation utilizes specific packet formats specifying various vital parameters used to control radio settings and pack
37. by the 4790 for power on reset if left unconnected After a stable power on reset a logic High pulse will reset the transceiver Signal Ground When logic Low the transceiver interprets OEM Host data as command data When logic High the transceiver interprets OEM Host data as transmit data DAEROCOMM 2 7 Version 1 4 SPECIFICATIONS Pin Definitions Table 2 AC4790 Pin Definitions Module 3 Function Pin 18 153 AD In 10 bit Analog Data Input 19 1 8 20 N C Do Not Has internal connection for AeroComm use only 24 28 Connect 20 18 Session When logic Low the transceiver is in Session Status N A 14 RF RF Port RF Interface N A 22 Reset Active Low version of UP RESET If RESET is used UP RESET should be left floating and if UP RESET is used RESET should be left floating 1 When ordered with a RS 485 interface not available on the AC4790 1x1 2 Must be tied to VCC or GND if not used Should never be permitted to float 3 If used requires a shunt 0 1uF capacitor at pin 15 followed by a series 1k resistor 2 8 AEROCOMM Version 14 SPECIFICATIONS Electrical Specifications ELECTRICAL SPECIFICATIONS Table 3 Input Voltage Characteristics 47901 1 AC4790 1000M AC4790 200X Signal Name High Low Low High High Low Low Min Min Min RS485A B N A 12 7 N A N A 12 7 N A RXD 2 3
38. d two RSSI values RSSI is how strong the remote transceiver heard the local transceiver and RSSI is how strong the local heard the remote transceiver 81 07 XX XX 12 34 A1 61 6C 6C 67 6F 6F 64 Payload Data ALL GOOD Source MAC Address RSSI RSSI Payload Data Length It may be useful to the OEM Host to determine which radio each packet originated from When Receive API is enabled every packet received by the transceiver will be received in the above format 1 52 AEROCOMM Version 14 APPENDIX III API Daisy Chain Repeater Network Normal Receive Mode If Receive API is not enabled the transceiver will receive the reply data only i e from each transceiver 61 6C 6C 67 6F 6F 64 Received Dala GOOD DAISY CHAIN REPEATER NETWORK For applications spanning long distances and cases where the desired radio is not within range of the sending radio a daisy chaing type network can be implemented With the use of API commands a processor and external buffer a daisy chain or repeater can easily be implemented to store and forward the data to the desired radio The example below assumes that radio A has a packet which needs to be received by radio D far right V y V 4 WV Vy MAC 12 34 56 MAC 12 34 A1 MAC 12 34 A2 MAC 12 34 A3 1 Radio A transmits the string FIND D to Radio B using the Transmit API command 81 06 08 04 12 34 1 66 69 GE 64 20 64 Paylo
39. e large enough to be readiily legible consistent with the dimensions of the equipment and the label However the type size for the text is not required to be larger than eight point 10 44 AEROCOMM Version 14 COMPLIANCY INFORMATION Antenna Requirements ANTENNA REQUIREMENTS WARNING This device has been tested with an MMCX connector with the above listed antennas When integrated into the OEM s product these fixed antennas require professional installation preventing end users from replacing them with non approved antennas Any antenna not listed in the above table must be tested to comply with FCC Section 15 203 for unique antenna connectors and Section 15 247 for emissions Contact AeroComm for assistance Caution Any change or modification not expressly approved by AeroComm could void the user s authority to operate the equipment WARNINGS REQUIRED IN OEM MANUALS WARNING This equipment has been approved for mobile applications where the equipment should be used at distances greater than 20 cm from the human body with the exception of hands feet wrists and ankles Operation at distances of less than 20 cm is strictly prohibited and requires additional SAR testing CHANNEL WARNING The OEM must prevent the end user from selecting a channel not approved for use by the FCC 10 45 AEROCOMM Version 14 APPENDIX SAMPLE POWER SUPPLY Below is a simple switching power supply that provides enough current to easily
40. ed at maximum allowable power Read Temperature The OEM Host issues this command to read the onboard temperature sensor The transceiver reports the temperature in C where 0x00 0 80 corresponds to 0 80 C and where OxD8 0x00 corresponds to 40 0 C DAEROCOMM CONFIGURING THE AC4790 Command Descriptions Command OxCC 0x11 Number of Bytes Returned 4 Response 0xCC MAC2 MAC1 Parameter Range 0x00 OxFF corresponding to LSB s of destination MAC Address Command OxCC 0x15 Data1 Number of Bytes Returned 2 Response 0xCC Data2 Parameter Range Data1 bit 0 Auto Destination bit 4 Enable Auto Destination modification Data2 bit 0 New Auto Destination setting bits 2 7 0 Command OxCC 0x16 Number of Bytes Returned 2 Response 0 API Control Command OxCC 0x17 Number of Bytes Returned 2 Response API Control Command OxCC 0x25 Max Power Number of Bytes Returned 2 Response OxCC Max Power Command OxCC 4 Number of Bytes Returned 2 Response OxCC Temperature Parameter Range Temperature OxD8 0x80 6 30 Version 1 4 CONFIGURING THE 4790 Command Descriptions Read Digital Inputs The OEM Host issues this command to read the state of Command 0 0x20 both digital input lines Number of Bytes Returned 2 Response 0xCC Data1 Parameter Ra
41. equipment are specifically not recommended without additional testing for such application Limited Warranty Disclaimer Limitation of Liability For a period of one 1 year from the date of purchase by the OEM customer AeroComm warrants the OEM transceiver against defects in materials and workmanship AeroComm will not honor this warranty and this warranty will be automatically void if there has been any 1 tampering signs of tampering 2 repair or attempt to repair by anyone other than an AeroComm authorized technician This warranty does not cover and AeroComm will not be liable for any damage or failure caused by misuse abuse acts of God accidents electrical irregularity or other causes beyond AeroComm s control or claim by other than the original purchaser In no event shall AeroComm be responsible or liable for any damages arising From the use of product From the loss of use revenue or profit of the product or As a result of any event circumstance action or abuse beyond the control of AeroComm whether such damages be direct indirect consequential special or otherwise and whether such damages are incurred by the person to whom this warranty extends or third party If after inspection AeroComm determines that there is a defect AeroComm will repair or replace the OEM transceiver at their discretion If the product is replaced it may be a new or refurbished product DAEROCOMM hes DOCUMENT INFORMATION Revisi
42. ery purposes only as some functionality is disabled in this mode RSSI INSTANTANEOUS RSSI Received Signal Strength Indicator is used by the OEM Host as an indication of instantaneous signal strength at the receiver The OEM Host must calibrate RSSI without an RF signal being presented to the receiver Calibration is accomplished by following the steps listed below 1 Power up only one transceiver in the coverage area 2 Measure the RSSI signal to obtain the minimum value with no other signal present 3 Power up another transceiver and begin sending data from that transceiver to the transceiver being measured Make sure the two transceivers are separated by approximately ten feet 4 Measure the peak RSSI while the transceiver is in Session to obtain a maximum value at full signal strength VALIDATED RSSI As RSSI is only valid when the local transceiver is receiving an RF packet from a remote transceiver instantaneous RSSI can be very tricky to use Therefore the transceiver stores the most recent valid RSSI value The OEM Host issues the Report Last Good RSSI command to request that value Additionally validated RSSI can be obtained from Receive Packet and Send Data Complete API commands and from the Probe command Validated RSSI is not available at the RSSI pin The following equation approximates the RSSI curve Signal Strength dBm 46 9 x VRSSI 53 9 5 24 AEROCOMM Version 14 HARDWARE INTERFACE Pin Definitions
43. et routing on a packet by packet basis The API features can be used in any combination that suits the OEM s specific needs 3 13 AEROCOMM Version 14 THEORY OF OPERATION API CONTROL API Transmit Packet API Transmit Packet is a powerful command that allows the OEM Host to send data to a single or multiple broadcast transceivers on a packet by packet basis This can be useful for many applications including polling and or mesh networks Refer to the API Appendix for further details API Transmit Packet is enabled when bit 1 of the API Control byte is enabled The OEM Host should use the following format to transmit a packet over the RF Payload Data Session Transmit T 0x81 Length Count Retries Broadcast MAG eto ie 0x01 0x80 Refresh Attempts pu 1 Ifthe OEM Host does not encode the header correctly the transceiver will send the entire string up to 0x80 bytes and will look for the header in the next data 2 Although the 7 bytes of overhead are not sent over the RF they are kept in the buffer until the packet is sent Keep this in mind so as not to overrun the 256 byte buffer 3 Setting the MAC to OxFF OxFF OxFF will broadcast the packet to all available transceivers API Send Data Complete API Send Data complete can be used as a software acknowledgement indicator When a radio sends an addressed packet it will look for a received acknowledgement transparent to OEM Host If an acknowledgement is not received
44. et to a minimum of 0x06 in order to send the Enter AT Command mode command FLOW CONTROL Flow control refers to the control of data flow between transceivers It is the method used to handle data in the transmit receive buffer and determines how data flow between the transceivers is started and stopped Often one transceiver is capable of sending data much faster than the other can receive and flow control allows the slower device to tell the faster device when to pause and resume data transmission When a transceiver has data to send it sends a Ready To Send signal and waits for a Clear To Send response from the receiving unit If the receiving radio is ready to accept data it will assert its CTS low CTS will be reasserted when the buffer contains the number of bytes specified by CTS OFF EEPROM address Ox5D These signals are sent apart from the data itself on separate wires ENGINEER S TIP Can implement a design using just Txd Rxd and Gnd Three wire Interface Yes However it is strongly recommended that your hardware monitor the CTS pin of the radio CTS is taken High by the radio when its interface buffer is getting full Your hardware should stop sending at this point to avoid a buffer overrun and subsequent loss of data You can perform a successful design without monitoring CTS However you need to take into account the amount of latency the radio adds to the system any additional latency caused by Transmit Retries or
45. f the parameters that can be read written by the OEM Host Factory default values are also shown Do not write to any EEPROM addresses other than those listed below Do not copy one transceivers EEPROM to another transceiver as doing so may cause the transceiver to malfunction EEPROM Length Table 12 EEPROM Parameters Parameter Default Description Address Bytes 9 Product ID 0x00 40 40 bytes Product identifier string Includes revision information for software and hardware Stop Bit Delay 0x3F 1 0x00 OxFF For systems employing the RS 485 interface or Parity OxFF the serial stop bit might come too early Stop bit delay controls the width of the last bit before the stop bit occurs OxFF Disable Stop Bit Delay 12 us 0x00 256 1 6 us 12 us 0x01 OxFE value 1 6 us 12 us Channel Number 0x40 1 0x00 1x1 0x00 Set 0 0x00 05 1x1 200 Ox37 200 0x00 Set 1 0x10 Ox2F US Canada 1x1 1000 1000 0x10 Set 2 0x30 0x37 US Canada 1x1 200 Australia 1x1 200 1000 Baud Rate Low 0x42 1 Ox00 OxFC Low byte of the interface baud rate Default baud rate OxFF is 57 600 Baud Rate High 0x43 1 0x00 0x00 High byte of interface baud Always 0x00 Control 0 0x45 1 0x00 Settings are bit 7 0 bit 6 DES Enable 0 Disable 1 Enable bits 5 0 0 Transmit Retries 0x4C 1 0x01 0x10 Maximum number of times a packet is sent out when OxFF Addressed packets are
46. hat it is a broadcast or addressed sync pulse it will respond by going into session with the radio A transceiver will enter Transmit or Command mode when the OEM Host sends data over the serial interface The state of the Command Data pin Pin 17 or the data contents determine which of the two modes will be entered Transmit Mode All packets sent over the RF are either Addressed or Broadcast packets Broadcast and Addressed delivery can be controlled dynamically with the API Control byte and corresponding on the fly commands To prohibit transceivers from receiving broadcast packets Unicast only can be enabled ADDRESSED PACKETS When sending an addressed packet the RF packet is sent only to the receiver specified in destination address To increase the odds of successful delivery Transmit retries are utilized Transparent to the OEM Host the sending radio will send the RF packet to the intended receiver If the receiver receives the packet free of errors it will return an RF acknowledge within the same 50 ms hop If a receive acknowledgement is not received the radio will use a transmit retry to resend the packet The radio will continue sending the packet until either 1 an acknowledgement is received or 2 all transmit retries have been used The received packet will only be sent to the OEM Host if and when it is received free of errors BROADCAST PACKETS When sending a broadcast packet the RF packet is sent out to every eligible tr
47. ic stations To prevent overlaps guard intervals can be inserted to absorb small timing errors in burst arrivals TDMA Frame GB1 RadioAData GB2 RadioB Data GB3 RadioC Data GB4 1 Timeslot I 55 DAEROCOMM APPENDIX III API Time Division Multiple Access Network Example Shared Access Point SAP sends broadcast packet which includes a sync pulse Remote radios hear the sync pulse and join the session Radio A transmits during time interval t 1 Radio B transmits during time interval t 2 Radio transmits during time interval t 1 This type of implementation requires careful planning and should allow enough time for retries if necessary When full duplex is enabled the radio which initiated the Session SAP will transmit during the even numbered hops and the remote radios will transmit only during odd numbered hops I 56 DAEROCOMM serio t APPENDIX IV API TIMING DIAGRAMS TIMING DIAGRAMS Session Count 8 Retries 3 RadicA TKD zi Radio Session Bea Radic Hop RadioA RF TX TXD mr He o RadioB Session 15 risk RadioB Hop mamme BadioC TxD Radiol RXD mediac DARK RedicC
48. into two classes within 2 5 cm of human contact and beyond 2 5 cm Note Ankles feet wrists and hands are permitted to be within 2 5 cm of the antenna even if the equipment is designated as being greater than 2 5 cm The AC4790 is not agency approved for portable applications The OEM is required to have additional testing performed to receive this classification Contact AeroComm for more details Mobile Mobile defines equipment where the user will be 20 cm or greater from the transmitting equipment The antenna must be mounted in such a way that it cannot be moved closer to the user with respect to the equipment although the equipment may be moved Note Ankles feet wrists and hands are permitted to be within 20 cm of mobile equipment OEM EQUIPMENT LABELING REQUIREMENTS WARNING The OEM must ensure that FCC labeling requirements are met This includes a clearly visible label on the outside of the OEM enclosure specifying the appropriate AeroComm FCC identifier for this product as well as the FCC notice below The FCC identifiers are listed above Contains FCC ID KQLAC4490 100 KQLAC4490 The enclosed device complies with Part 15 of the FCC Rules Operation is subject to the following two conditions 1 This device may not cause harmful interference and 2 This device must accept any interference received including interference that may cause undesired operation Label and text information should be in a size of typ
49. is MAC LAM 34 2 12 34 5 4 MAC 12 34 A4 MAC 12 34 56 Shared Access Point MAC 12 34 AS MAC 12 34 A6 Channel 0x10 System ID 0x01 The simplest implementation consists of a smart Shared Access Point SAP with a microcontroller or processor of some type which has transmit API enabled The SAP controls which transceiver s each packet is routed to Broadcast packets should be used when all remotes are to receive the same message and addressed packets when communication with a single remote only is desired An example of each is shown in the following pages 1 50 APPENDIX III API Polling Network Addressed Transmit API 1 To poll radio 1 the SAP transmits the packet using the following format 81 06 08 04 12 34 A1 73 74 61 74 75 73 Payload Data STATUS Destination MAC Address Number of Transmit Retries Session Count Refresh Payload Data Length 2 To poll radio 2 the SAP transmits the packet using the following format 81 06 08 04 12 34 A2 73 74 61 74 75 73 Payload Data STATUS Destination MAC Address Number of Transmit Retries Session Count Refresh Payload Data Length 3 To poll radio 2 the SAP transmits the packet using the following format 81 06 08 04 12 34 A4 73 74 61 74 75 73 Payload Data STATUS Destination MAC Address Number of Transmit Retries Session Count Refresh Payload
50. lf Duplex 50 ms Number of retries Max random value Worst case latency Full Duplex 100 ms Number of retries Max random value NETWORKING System ID System ID EEPROM address 0x76 is similar to a password character or network number and makes network eavesdropping more difficult A transceiver will not establish a Session or communicate with a transceiver operating on a different System ID or Channel Number RF Channel Number Channels 0x00 OxOF and 0x30 0x37 hop on 26 different frequencies Channels 0x10 Ox2F use 50 different frequencies Table 9 RF Channel Number Settings RF Channel 2 Ch Set Number Range Erequency Details 8 Countries anne Regulatory requirements 0x40 0 AC4790 1x1 0x00 OxOF 902 928 MHz 26 hop bins US Canada AC4790 200 1 AC4790 1x1 0x10 Ox2F 902 928 MHz 50 hop bins US Canada AC4790 1000 2 AC4790 1x1 0x30 0x37 915 928 MHz 22 hop bins US Canada 1 1 200 4790 200 Australia 1x1 200 1000 4790 1000 1 All Channels in a Channel Set use the same frequencies in a different order DES Data Encryption Standard DES Data Encryption Standard Encryption is the process of encoding an information bit stream to secure the data content The DES algorithm is a common simple and well established encryption routine An encryption key of 56 bits is used to encrypt the packet The receiver must use the exact same key to decryp
51. nchronous serial data formats are supported Table 6 Supported Serial Formats Data Bits Transceiver Programming Requirements 8 N 1 Parity Disabled 7 N 2 Parity Disabled 7 1 Parity Disabled 9 N 1 Parity Enabled 8 N 2 Parity Enabled 8 1 Parity Enabled 7 5 2 Parity Enabled Mark corresponds to 1 amp Space S corresponds to 0 SERIAL INTERFACE BAUD RATE This two byte value determines the baud rate used for communicating over the serial interface to a transceiver The Table below lists values for some common baud rates Baud rates below 1200 baud are not supported For a baud rate to be valid the calculated baud rate must be within 3 of the OEM Host baud rate If the Test pin Pin 12 is pulled logic Low at reset the baud rate will be forced to 9 600 The RF baud rate is fixed at 76 8 Kbps and is independent of the interface baud rate For Baud Rate values other than those shown below the following equations can be used 4 17 AEROCOMM Version 1 4 SERIAL INTERFACE Interface Timeout RF Packet Size 14 7456x10 HE 64 x DesiredBaud BaudH Always 0 BaudL Low 8 bits of BAUD base 16 Table 7 Baud Rate Interface Timeout Baud Rate Stop Bit Delay 0x3F 115 200 OxFE 0x00 0x02 OxFF 57 600 OxFC 0x00 0x02 0x03 38 400 OxFA 0x00 0x02 0x08 28 800 OxF8 0x00 0x02 OxOE 19 200 OxF4 0x00 0x03 0x19 14 400 OxFO 0x00 0x04 0x23 9 600 Ox
52. nge Data1 bit 0 GIO bit 1 Gl1 Read Radio Table The OEM Host issues this command to read the Radio Command 0x18 Table that resides on the transceiver The Radio Table stores information for up to the last 8 transceivers that it Number of Bytes Returned Varies received a packet from This information can be useful for Response OxCC Transceivers MAC2 MAC1 determining alternative data paths MACO RSSI RSSI StaleCount MAC2 MAC1 MACO etc Stale Count The Stale Count Reload 0x04 determines the amount of time that a transceiver stays active in the Radio Table Stale Count min 0x00 max dependent on EEPROM setting for a radio is set to 0 when a packet is received and then incremented by one every 100 ms thereafter When the Stale Count of a transceiver reaches the Stale Count Reload 0x04 the transceiver is considered stale A Radio Table can hold information for up to 8 different transceivers however if the table is full and a ninth radio appears the first stale radio is replaced with the new radio If none of the radios are stale the oldest radio is replaced by the new radio Table 11 Received Signal Strength Signal Strength Signal Strength dBm RSSI Value Hex RSSI Value Hex dBm 4 OxOE 62 0x2B 2to1 0x0D 66 0 40 12 to 6 0x0C 69 0 55 36 to 22 0x0B 72 0 62 42 to 39 0x0C 76 0x71 46 0 79 0x78
53. nnel OxCC New Channel Broadcast OxCC 0x08 0x00 Broadcast OxCC 0x00 or 0x01 Packets 0x01 Addressed Write Destination OxCC 0x10 Byte 4 of Byte 5 Byte OxCC Byte 4 of Dest Byte 5 Byte 6 Address Dest MAC 6 MAC Read Destination OxCC 0x11 OxCC Byte 4 of Dest Byte 5 Byte 6 Address MAC Auto Destination OxCC 0x15 bit 0 Auto Destination OxCC bit 0 Auto Destination bit 4 Enable Auto Destination bits 1 7 0 Read API Control OxCC 0x16 OxCC API Control Write API Control OxCC Ox17 API Control OxCC API Control Read Digital Inputs OxCC 0x20 OxCC bit 0 GIO bit 1 Read ADC OxCC 0x21 0x01 AD In OxCC MSB of 10 bit LSB of 10 bit ADC 0x02 Temp ADC 0x03 RSSI Write Digital OxCC 0x23 bit 0 GOO OxCC bit 0 GOO Outputs bit 1 GO1 bit 1 GO1 Set Max Power OxCC 0x25 New Max Power OxCC Max Power Enter Probe OxCC Ox8E 0x00 Enter Probe OxCC 0x00 or 0x01 0x01 Exit Probe Read Temperature OxCC 0 4 OxCC Temp C EEPROM Byte Read OxCC OxCO Start Address Length OxCC Starting Length Data Address EEPROM Byte Write OxCC OxC1 Start Address Length Data Starting Address Length Data written Soft Reset OxCC OxFF 6 28 AEROCOMM Version 14 COMMAND DESCRIPTIONS Enter AT Command Mode Prior to sending this command the OEM Host must ensure that the transceiver s RF transmit buffer is empty If the buffer is not empty the radio will interpret the command a
54. on Description Version 1 0 2 21 05 Initial Release Version Version 1 1 3 4 05 Updated Session Count Truth Table Version 1 2 4 26 05 Updated Transmit Mode Section Version 1 3 3 17 06 Corrected Send Data Complete Added Australian Channels Added 1x1 documentation Added Appendices IV Version 1 4 6 25 06 Updated API Section Added Serial Communications Added Max Power backup EEPROM byte address Ox8E Added Product ID EEPROM bytes addresses 0x90 Ox9F Updated Compliancy Information Updated Appendices IV DAEROCOMM dd AC4790 TRANSCEIVER MODULE The compact AC4790 900 2 transceiver can replace miles of cable in harsh industrial environments Using field proven FHSS technology which needs no additional FCC licensing in the Americas OEMs can easily make existing systems wireless with little or no RF expertise AC4790 FEATURES NETWORKING AND SECURITY Masterless True peer to peer point to multipoint point to point Retries and Acknowledgements API Commands to control packet routing and acknowledgement on a packet by packet basis Frequency Hopping Spread Spectrum for security and interference rejection Customizable RF Channel number and system ID Dynamic link analysis remote radio discovery Software controlled sensitivity Hardware Protocol Status monitoring Two generic input and output digital lines and integrated ADC functions EASY TO USE Continuous 76 8 kbps RF data stream
55. our bytes Ox9A Ox9C Interface 232 485 Ox9D Ox9E Setup script 01 is stock Ox9F Reserved for future use always OxFF API Control OxC1 1 0x10 Settings are bit 7 Broadcast packets 0 Addressed Packets 1 Broadcast Packets bit 6 Probe 0 Disable Probe 1 Enable Probe bit 5 SLock1 0 Disable 1 Enable bit 4 SLockO 0 Disable 1 Enable bit 3 Unicast Packets 0 Broadcast or Addressed delivery 1 Addressed packets only bit 2 Send Data Complete Enable 0 Disable 1 Enable bit 1 API Transmit Packet Enable 0 Disable 1 Enable 0 API Receive Packet Enable 0 Disable 1 Enable 0 2 1 0x00 OxFF Protocol Status Determines if the GOO amp GO1 server as generic output or as protocol status OxC4 1 0x00 OxFF Session Count 0x08 Refresh Specifies the number of hops a transceiver stays in session with another transceiver DAEROCOMM 7 36 Version 1 4 Parameter EEPROM PARAMETERS Command Descriptions Table 12 EEPROM Parameters EEPROM Length Random Back Off Default Description Address Bytes 9 0 1 0x00 0x00 The random amount of time a transceiver waits when OxFF a collision occurs before resending the packet again 0x00 Disable Random Backoff 0x01 Wait 1 2 packet times then retry 0x03 Wait 1 4 packet times then retry 0x07 Wait 1 8 packet times then retry OxOF Wait 1 1
56. plex Note 2 It is best to have all transceivers with the same Session Count Refresh EEPROM Address 0 4 value Session Count Refresh must not be set to 0x00 Case 1 In this case a radio loads its Session Count with its Session Count Refresh This is suitable for Half Duplex communication where immediate response is not received from the remote radio 3 11 DAEROCOMM THEORY OF OPERATION Modes of Operation Case 2 In this case a radio loads its Session Count with its Session Count Refresh its Transmit Retries This case is suitable for applications where there are high levels of interference and it is likely that transmit retries will be necessary to maintain reliable communications When an addressed packet or a response to a broadcast packet is sent the sending radio will listen for a successful acknowledgement If an acknowledgement is not sent the radio will resend the packet until either an acknowledgement is received or it has exhausted all available transmit retries If two radios are on the last hop of the current session and a retry is required it is possible that once the current session has ended the receiving radio could go into session with a different radio and miss the final packet of the previous session Adding the radios Transmit retries to its Current Session Count will ensure that the radio does not exit the session when the remote radio is using a Transmit Retry Case 3 In this case a radio loads its Se
57. power any Aerocomm OEM module It utilizes low cost off the shelf components that fit into a small area This supply has an input voltage range of 6 volts to 18 volts and will output 3 4 volts at 1 5 amps Included is a schematic bill of materials with manufacture s name and part numbers and a sample PCB layout It is important to follow the layout suggestions and use large areas of copper to connect the devices as shown in the layout It is also important to hook up the ground traces as shown and use multiple vias to connect input and output capacitors to the bottom side ground plane If the input voltage will be less than 12 volts then C1 and C2 can be replaced with a single 100uF 20 volt capacitor same part number as C7 This will reduce board space and lower costs further If you are powering an AC5124 module R1 can be changed to a 373 ohm 1 resistor This will change the output to 5 volts at 1 0 amps BILL OF MATERIALS Table 15 Power Supply Bill of Materials Value Description Mfg part number 210 Res 0603 210 1 16W 196 RK73H1JT2100F 127 Res 0603 127 1 16W 1 RK73H1JT1270F 47uF Cap Tant 7343 47uF 35V TPSE476M035R0200 C3 C4 C5 0 1uF Cap Cer 0603 0 1uF 25V Murata GRM39Y5V104Z025AD C6 3300pF Cap Cer 0603 3300pF X7R 50V Murata GRM39X7R332K050AD C7 100uF Cap Tant 7343 100 20V Kemet T491X107K020A5 D1 B230 A Diode SMB B230 A 2A Schott Diodes Inc B230 A key D2 LL414
58. s data and it will be sent over the RF This can be accomplished by waiting up to one second between the last packet and the AT command Exit AT Command Mode The OEM Host should send this command to exit AT Command mode and resume normal operation Firmware Version Request The OEM Host issues this command to request the firmware of the transceiver Change Channel The OEM Host issues this command to change the channel of the transceiver Broadcast Packets The OEM Host issues this command to change the transceiver operation between Addressed Packets and Broadcast Packets If Addressed Packets are selected the transceiver will send all packets to the transceiver designated by the Destination Address programmed in the transceiver If Broadcast Packets are selected the transceiver will send its packets to all transceivers on that network Setting bit 7 of Control to 1 can also enable Broadcast Packets Write Destination Address The OEM Host issues this command to the transceiver to change the Destination Address Note Only the three Least Significant Bytes of the MAC Address are used for packet delivery DAEROCOMM CONFIGURING THE AC4790 Command Descriptions Command 0x41 0x54 Ox2B Ox2B 0x2B 0x0D Number of Bytes Returned 4 Response 0x43 0 4 Ox4D Command OxCC 0x41 0x54 Ox4F 0x0D Number of Bytes Returned 4 Response OxCC 0x44 0x41 0x54 Command 0 0x00 0x0
59. selected Broadcast 0x4D 1 Ox01 0x04 Maximum number of times a packet is sent out when Attempts OxFF Broadcast packets are selected Stale Count Ox4F 1 0x01 0x40 Determines the amount of time that a transceiver will Reload OxFF keep a radio active in its Receive Table This value is reset every time a packet is received from that radio DAEROCOMM 7 34 Version 1 4 EEPROM Table 12 EEPROM Parameters Length EEPROM PARAMETERS Command Descriptions Parameter Default Description Address Bytes 9 ED Control 1 0x56 1 0x43 Settings are bit 7 Aerocomm Use Only bit 6 Aerocomm Use Only bit 5 Aerocomm Use Only bit 4 Auto Destination 0 Use destination address 1 Use auto destination bit 3 Aerocomm Use Only bit 2 RTS Enable 0 Ignore RTS 1 Transceiver obeys RTS bit 1 Duplex 0 Half Duplex 1 Full Duplex bit 0 Auto Config 0 Use EEPROM values 1 Auto Configure values Interface Timeout 0x58 1 0x02 0x04 Specifies a byte gap timeout used in conjunction OxFF with RF Packet Size to determine when a packet coming over the interface is complete 0 5 ms per increment RF Packet Size 0x5B 1 0x01 0x80 Used in conjunction with Interface Timeout specifies 0x80 the maximum size of an RF packet CTS On 0 5 1 0 01 OxD2 CTS will be deasserted High when the transmit OxFF buffer contains at least this many char
60. ssion Count with the remote radio s Session Count This is suitable for full duplex applications as the Session is extended as long as there is communication Note This is the default case with which the radio ships and works well for almost all applications Case 4 In this case a radio loads its Session Count with the remote radio s current Session Count This is suitable for daisy chain applications and large networks in which radios cannot stay in session longer than needed Command Mode A radio will enter Command Mode when data is received over the serial interface from the OEM Host and either the Command Data pin pin 17 is logic Low or the received data contains the Enter AT Command Mode command Once in Command Mode all data received by the radio is interpreted as command data Command Data can be either EEPROM Configuration or On The Fly commands 3 12 DAEROCOMM m THEORY OF OPERATION API CONTROL Figure 1 Pending RF and Data in Buffer Flow b gt Receive Mode 4 Receive Mode N J 4 Y Pending RE Data in Buffer Received oN Pd CIC Va N Yes Broadcast s Command Data Pin boa S Discard Packet X Packet Disc
61. t the packet otherwise garbled data will be produced To enable DES EEPROM Byte 0x45 bit 6 must be set to a value of 1 To disable DES set bit 6 to a value of 0 The 7 byte 56 bits Encryption Decryption Key is located in EEPROM Bytes OxDO OxD6 It is highly recommended that this Key be changed from the default 4 21 AEROCOMM Version 14 SERIAL INTERFACE Max Power MAX POWER Max Power provides a means for controlling the RF output power of the AC4790 Output power and current consumption can vary by as much as 10 per transceiver for a particular Max Power setting Contact AeroComm for assistance in adjusting Max Power ENGINEER S The max power is set during Production and may vary slightly from one transceiver to another The max power can be set as low as desired but should not be set higher than the original factory setting A backup of the original power setting is stored in EEPROM address Ox8E 4 22 DAEROCOMM vein HARDWARE INTERFACE Below is a description of all hardware pins used to control the AC4790 PIN DEFINITIONS Generic 1 0 Both Gln pins serve as generic input pins When Protocol Status byte OxC2 of EEPROM is disabled GOO amp GO1 serve as generic outputs When Protocol Status is enabled pins GOO and GO alternatively serve as the Session Status and Receive Acknowledge Status pins respectively Reading and writing of these pins can be performed using CC Commands HARDWARE PR
62. the packet will be retransmitted until one is received or all retries have been used For applications where data loss is not an option the OEM Host may wish to monitor the acknowledgement process using the API Send Data Complete If an acknowledgement is not received Failure the OEM Host can send the packet to the transceiver once again API Send Data Complete is enabled when bit 2 of the API Control byte is enabled The transceiver sends the OEM Host the following data upon receiving an RF acknowledge or exhausting all attempts 0x00 Failure eee RSSI 0x01 Success 1 RSSI is how strong the remote transceiver heard the local transceiver RSSI is how strong the local transceiver heard the remote transceiver 2 Successful RF Acknowledge updates the Success Failure bit 3 Asuccess will always be displayed when sending broadcast packets after all broadcast attempts have been exhausted API Receive Packet By default the source MAC is not included in the received data string sent to the OEM Host For applications where multiple radios are sending data it may be necessary to determine the origin of a specific data packet When API Receive Packet is enabled all packets received by the transceiver will include the MAC address of the source radio as well as an RSSI indicator which can be used to determine the link quality between the two 3 14 AEROCOMM Version 14 THEORY OF OPERATION API CONTROL A
63. to 80 C Temperature Storage 50 C to 85 C Humidity non condensing Dimensions 10 to 90 Physical Transceiver with MMCX Connector 1 65 x 1 9 x 0 20 Transceiver with Integral Antenna 1 65 x 2 65 x 0 20 AC4790 1x1 1 00 x 1 00 x 0 162 Certifications AC4790 200 AC4790 1000 FCC Part 15 247 KQLAC4490 100 KQLAC4490 Industry Canada IC 2268C AC4490 2268C AC44901000 PIN DEFINITIONS The AC4790 has a simple interface that allows OEM Host communications with the transceiver The table below shows the connector pin numbers and associated functions The I O direction is with respect to the transceiver All outputs are 3 3VDC levels and inputs are 5VDC TTL with the exception of AC4790 1x1 and AC4790 1000 transceivers which have 3 3V inputs All inputs are weakly pulled High and may be left floating during normal operation with the exceptions listed for the AC4790 1x1 Table 2 AC4790 Pin Definitions 1 1 Signal Pin Pin Type Function 1 4 Session status if Protocol Status is enabled Otherwise generic output 2 6 TXD Transmitted data out of the transceiver 2 6 Version 1 4 SPECIFICATIONS Pin Definitions Table 2 AC4790 Pin Definitions Function Module 1 1 1 0 RS485 A True 3 7 1 0 RS485 B Invert 1 4 52 GIO 5 3 GND GND 6 Do Not Connect 7 9 CTS
64. will increase also SYSTEM THROUGHPUT When operating as shown below an AC4790 transceiver is capable of achieving the listed throughput However in the presence of interference or at longer ranges the transceiver may be unable to meet the specified throughput Table 8 Maximum System Throughput Half Duplex TAN De Rf Status TE 6 bna Throughput bps gnp P each way Radio not in continuous session 25k 12 5k Radio continuously in session 45k 22 5k RANDOM BACKOFF Random Back Off The transceivers utilize a Carrier Sense Multiple Access CSMA protocol with random back off and a selectable back off seed In the event of a collision the transceiver will back off and retry the packet Specifically when two transceivers detect a collision each transceiver will choose a random number of packet times that it will wait before retrying the 4 20 AEROCOMM Version 14 SERIAL INTERFACE Networking packet This random number is selected from a pool of numbers defined by the back off seed and consists of a number between 1 and 2 1 and 4 1 and 8 1 16 1 and 32 1 and 64 1 and 128 and 1 and 256 In a very dense network where more than two transceivers could experience a collision it is important to have a higher random back off seed ENGINEER S What effects will Random Backoff have on system latency As the random backoff value increases the overall system latency increases Worst case latency Ha

AC4790 User`s Manual v1.4.fm

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